Northern Watch Air Surveillance with a Rutter 100S6 Radar System – Trials Analysis and Results

Dan Brookes DRDC Ottawa

Defence R&D Canada – Ottawa Technical Memorandum DRDC Ottawa TM 2013-152 November 2013

Northern Watch Air Surveillance with a Rutter 100S6 Radar System - Trials Analysis and Results

Dan Brookes DRDC Ottawa

Defence R&D Canada – Ottawa Technical Memorandum DRDC Ottawa TM 2013-152 November 2013

Principal Author

Original signed by Dan Brookes Dan Brookes Defence Scientist

Approved by

Original signed by Rahim Jassemi Rahim Jassemi Acting Head, Space and ISR Applications Section

Approved for release by

Original signed by Chris McMillan Chris McMillan Chair, Document Review Panel

© Her Majesty the Queen in Right of Canada, as represented by the Minister of National Defence, 2013 © Sa Majesté la Reine (en droit du Canada), telle que représentée par le ministre de la Défense nationale, 2013

Abstract ……..

This document describes an initial assessment of the Rutter 100S6 marine radar system’s ability to perform a useful function as a limited air surveillance asset at a remote test site on Devon Island, overlooking Barrow Strait and Lancaster Sound. As part of the assessment, a set of trials was performed in the Ottawa-Gatineau area to measure the radar system’s ability to detect and track aircraft of opportunity in a land-based setting. The aircraft were of various types and sizes ranging from small general aviation aircraft (fixed and rotary wing) to large commercial jet airliners. Ground-truth of the aircraft classification, identification and course information was provided by a combination of visual means (i.e. naked eye, binoculars, and camera imagery) and, when available, Automatic Dependent Surveillance-Broadcast (ADS-B) reports. Only a few days of actual data collection was accomplished, which was performed intermittently over the period from 29 July to 19 September 2010. The outcome of the assessment was that this radar system has the potential to provide a useful, though limited, air surveillance role as long as the system constraints are respected. It was also determined that a more capable tracker would be needed if automatic surveillance of aircraft, with minimal analyst intervention, is required. The current alpha-beta tracker provided with radar system has difficulty initiating a track or maintaining track continuity on high speed (over 100 kph) manoeuvring targets, especially given their tendency for scintillation.

Résumé ….....

Ce document décrit une première évaluation de la capacité d'un système de radar de marine, le Rutter 100S6, pour remplir une fonction utile comme un atout pour la surveillance limitée des avions sur un site de test à distance sur l'île Devon, avec une vue sur les détroits de Barrow et de Lancaster. Dans le cadre de l'évaluation, une série d'essais a été réalisée dans la région d'Ottawa- Gatineau pour mesurer la capacité du système de radar pour détecter et suivre les avions d'occasion dans un cadre terrestre. Les avions étaient de différents types et tailles allant de petits avions de l'aviation générale (fixe et à voilure tournante) aux grands avions de ligne commerciaux. Rez-de-vérité de l'information pour la classification, l'identification et trajectoires de vol des aéronefs a été fourni par une combinaison de moyens visuels (à savoir l'œil nu, des jumelles, et l'imagerie de la caméra) et, lorsqu'il est disponible, la surveillance dépendante automatique en mode diffusion (ADS-B) rapports. Seulement un peu de jours de collecte de données réelles ont été accomplies; ils ont été réalisés par intermittence au cours de la période allant du 29 Juillet au 19 Septembre 2010. Le résultat de l'évaluation était que ce système radar a le potentiel de fournir un utile, bien que limité, le rôle de surveillance de l'air à condition que les contraintes du système sont respectées. Il a également été déterminé qu'un plus capable algorithme de poursuite serait nécessaire si la surveillance automatique des avions, avec un montant minimal de l'intervention par l'analyste, est nécessaire. Le courant traqueur alpha-bêta fourni avec le système radar a difficulté à initier une piste ou le maintien de la continuité de la piste pour les cibles de manœuvre à grande vitesse (plus de 100 km), en particulier en raison de leur tendance à scintiller.

DRDC Ottawa TM 2013-152 i

This page intentionally left blank.

ii DRDC Ottawa TM 2013-152

Executive summary

Northern Watch: Air Surveillance with a Rutter 100S6 Radar System- Trials Analysis and Results Brookes, D.; DRDC Ottawa TM 2013-152; Defence R&D Canada – Ottawa; November 2013.

Introduction or background: In 2008, at the beginning of the implementation phase of the Northern Watch (NW) Technology Demonstration Program (TDP) project, a Rutter 100S6 maritime navigation radar was purchased. Its main purpose was to be used as an all-weather sensor capable of detecting, localizing, and tracking both cooperative and non-cooperative surface vessels as part of an integrated suite of complementary above water and underwater sensors for local maritime surveillance. The objective of the integrated suite was to be able to detect, track, classify and possibly identify sub-surface, and surface vessels as well as provide limited surveillance of aircraft.

Since the Rutter 100S6 was designed for detecting and tracking marine surface vessels, its effectiveness as an air surveillance asset for Northern Watch needed to be assessed. In order to perform this assessment, experimental trials were performed (over land) at the Gatineau Executive Airport (GEA), in Gatineau, Quebec, during the late summer of 2010.

Results: The following observations and conclusions can be made about the ability of the Rutter 100S6 radar system to detect and track aircraft over land in good weather conditions.

1) The aircraft usually needs to be within the volume scanned by the main beam of the radar (i.e. a vertical angle between -12° and 12° relative to the horizontal boresight, and azimuth angle between 0° and 360°) to be detected and tracked.

2) The detection range of the aircraft depends on the type, size and aspect angle:

a. Small low winged aircraft can be detected and tracked to a maximum range of about 15 km when viewed tail-on.

b. Larger aircraft the size of the PBY-5A Canso or the Lancaster Mark X can be detected and tracked to a range of just over 30 km when viewed tail-on.

c. Large commercial airliners like the Boeing 737-300 can be seen for brief periods at ranges of up to 50 km when viewed at an optimal angle of broadside, and within the main beam of the radar antenna (i.e. up to 36000 ft). At other times it can usually be detected and tracked to ranges between 30 and 35 km.

d. Very large aircraft such as the Boeing 767 and Airbus A320 or A330 can usually be detected to a range of 40 km and to altitudes up to 36000 ft (within the 12°) regardless of aspect angle and up to 50 km when seen broadside.

DRDC Ottawa TM 2013-152 iii

3) Unless the aircraft maintains a relatively straight bearing, the alpha-beta tracker that comes with the radar system has difficulty maintaining a track lock. This is expected since the radar was originally intended as a marine navigation aid to detect and track relatively slow moving marine targets. The aircraft observed in these trials had airspeeds that usually exceeded 150kph and went as high a 600kph. At such speeds, manoeuvring aircraft are difficult to track because the radar only has a maximum update rate of about 1.3 seconds between rotational scans (48 rpm). These problems are exacerbated when the aircraft is at a range and aspect where there are a significant number of missed detections conflicting with the required tracking criteria (e.g. M-of-N detection parameter). A more advanced tracking algorithm would probably provide better results, especially if the tracking was not required to be in real-time.

4) With the current signal processing and tracker, initiating a track in heavy ground clutter (especially in Long Range mode) near the radar site is generally not possible. This can limit the tracking capability to ranges beginning at more than a kilometre from the radar site, in reasonably flat terrain. In general, ground clutter is highly terrain dependent but may be reduced by suitably locating the radar on a summit.

5) Maintaining a track through areas of heavy ground clutter can be problematic, and depends on the speed of the aircraft and the width of the clutter with respect to the track.

6) The results obtained in these experiments are consistent with the prediction software (SIESTA) that a high-winged aircraft the size of a DHC-6 Twin-Otter might be seen by the 100S6 radar to a distance of over 30 km, as long as it is broadside to the radar beam.

It was found that one method of obtaining ground truth course information for the radar, i.e. ADS-B reports from aircraft, was not always acccurate. During the trials, at least one Air Canada B767-38E(ER) passenger aircraft had a positional offset of over 12 km to the West, and 1 km to the South of the true route.

Significance: Based on the outcomes of these experiments, and of ADS-B reports collected from aircraft flying in the vicinity of Cape Liddon during NW sensor trials in August of 2008, the density of trans-polar flights might be great enough for the 100S6 to detect and track several aircraft per week, at least for brief periods of time, depending on their aspect, range and altitude.

Future plans: It would be useful to apply more sophisticated tracking algorithms to the Rutter 100S6 data recorded during the GEA trials to determine whether significantly better performance might be achieved for tracking aircraft. Although some of these algorithms can be computationally intensive, this may not be a problem if the tracks do not need to be reported in real-time. A tracking latency of several minutes to an hour may be acceptable for the Arctic where response times are typically measured in terms of several hours. The next obvious step in this work would be the testing of the radar at its intended site at Gascoyne Inlet or Cape Liddon.

iv DRDC Ottawa TM 2013-152

Table of contents

Abstract ……...... i Résumé …...... i Executive summary ...... iii Table of contents ...... v List of figures ...... vii List of tables ...... xvi Acknowledgements ...... xvii 1 Introduction ...... 1 2 Radar System Performance Prediction for Aircraft ...... 3 2.1 Monostatic RCS Estimates ...... 7 3 Trials Planning, Setup, and Execution ...... 15 4 Analysis and Results ...... 22 4.1 Tracking of Small to Medium Sized Aircraft ...... 22 4.1.1 Small Aircraft Detection and Tracking on 30 July, and 6-11 Aug...... 23 4.1.2 Gatineau Air Show 17-19 Sept. 2010...... 27 4.2 Commercial Flights 29 July to 18 Sept. 2010 ...... 38 4.2.1 Three Dimensional Views of Flight Paths Based on ADS-B Reports...... 38 4.2.1.1 29 July 2010 ...... 39 4.2.1.2 30 July 2010 ...... 41 4.2.1.3 6 August 2010 ...... 44 4.2.1.4 11 August 2010 ...... 45 4.2.1.5 30 July 2010 ...... 52 4.2.1.6 17 Sept. 2010 ...... 52 4.2.1.7 18 Sept. 2010 ...... 57 4.2.2 Two Dimensional Plan Views Comparing the Radar Tracks and ADS-B Reported Flight Paths ...... 61 4.2.2.1 29 July 2010 ...... 62 4.2.2.2 4 August 2010 ...... 63 4.2.2.3 30 July 2010 ...... 63 4.2.2.4 6 August 2010 ...... 67 4.2.2.5 11 August 2010 ...... 68 4.2.3 17 September 2010 ...... 73 4.2.4 18 September 2010 ...... 74 5 Conclusions ...... 88 References ...... 93 Annex A .. Estimation of Aircraft RCS ...... 95

DRDC Ottawa TM 2013-152 v

Annex B. Rutter 100S6 Radar System Specifications and SIESTA Set-up ...... 101 Annex C. Aircraft Observed at the Gatineau Executive Airport from 29 July to 19 Sept. 2010. 104 C.1 Time-stamped Photographs of Small and Medium Sized Aircraft Observed at GEA...... 110 C.1.1 30 July 2010 ...... 110 C.1.2 6 August 2010 ...... 111 C.1.3 11 August 2010 ...... 112 C.1.4 17 September 2010 ...... 114 C.1.5 18 September 2010 ...... 119 Annex D .. Aircraft Specifications ...... 130 List of abbreviations/acronyms ...... 133 Distribution list ...... Error! Bookmark not defined.

vi DRDC Ottawa TM 2013-152

List of figures

Figure 1: Photographs of the DHC-6 Twin Otter (top row) and ATR42-300 (bottom row) that, with the exception of the upper left (by K. Kollenberg), were taken by the author while on a trip to Devon Island in July 2007...... 3 Figure 2: Assumed vertical antenna gain for the Rutter 100S6 based on a 3 dB elevation 2 2 beamwidth of 24° and a typical beampattern of sin x/x (x=6.7 sin(el)) associated with a rectangular aperture. (Note: the importance of the intersection point at 37° will be made apparent later in Section 4.2.4.) ...... 4 Figure 3: Geometry of a low flying aircraft with respect to a Rutter 100S6 radar if placed on top of Cape Liddon at an altitude of 320 m above sea level (ASL)...... 5 Figure 4: Geometry and assumptions used to estimate the pattern propagation factor, F, for the radar equation. Here E is the electric field vector for a horizontally polarized radar signal, rD is the length of the direct signal path, rI is the length of the reflected signal path, ρ is the reflection coefficient,  is the phase change on reflection, Ro is the target’s horizontal range, h is the antenna height and z is the target height...... 6 Figure 5: Pattern Propagation Factor “F” for four different scenarios. On the left, the antenna and target heights were 10m and 100m respectively, with the blue and black curves representing reflection coefficients of 0.9 and 0.3 respectively. On the right, the same reflection coefficients were used but the antenna and target heights were changed to 50m and 400m respectively...... 7 Figure 6: Measured backscatter (RCS) from a one-fifteenth scale model of a Boeing 737 at 10 GHz, vertical polarization [6][7][8]. This is equivalent to a radar frequency of 667MHz for a full scale aircraft...... 8 Figure 7: Contribution to the RCS profile of a Boeing 737-600 based on a cylindrical model for the main portion of the aircraft fuselage. The plot on the right is an expanded portion of the image on the left...... 9 Figure 8: Azimuth dependence of the dihedral corner formed by the main wing joining the fuselage, based on the simple model shown in Annex A. In most instances, this dihedral wouldn’t be visible to the radar unless the B-737 made a banking turn such that the upper surfaces of the airframe faced the antenna...... 10 Figure 9: Examples of a dihedral and trihedral corner reflector are shown in the upper frame. The areas where the aircraft wings meet the fuselage, as shown in the stylized air frame at the bottom, are examples of a dihedral corner reflector...... 11 Figure 10: The DHC-6 Twin Otter shown in the lower right is a typical size expected for low flying aircraft in the Arctic. While its RCS profile is not known, it is expected, based on its dimensions, to be similar to that of the B-26 Marauder [12][13]shown on the left...... 12 Figure 11: SIESTA radar coverage prediction for low flying air contacts at altitudes of 400 m ASL (1300 ft). The cross at 33 km represents the maximum range for an aircraft the size of the B-26 when it is broadside to the Rutter 100S6 radar beam...... 13

DRDC Ottawa TM 2013-152 vii

Figure 12: Example of a 300m CAPPI plot from SIESTA when the antenna height was only 110 m ASL. The ring structure due to coherent specular multipath interference from sea surface reflections is very evident at the longer ranges. This is despite assuming a sea state of 4 (waves 1.25 to 2.5 m high)...... 14 Figure 13: As shown in the above series of maps and aerial photographs from Google Earth, the Shirley’s Bay campus of DRDC Ottawa is within about 30 km to three small airports for small aircraft, as well as one large international airport...... 16 Figure 14: This aerial photograph from Google Earth shows where the radar system would have been located on the Shirley’s Bay campus of DRDC Ottawa if that plan had gone forward. It also shows the directions and distances to four local airports of greatest significance...... 17 Figure 15: MRL truck “architecture”. The stabilizer shown in the diagram was necessary to minimize the swaying of the cargo box from swaying in windy conditions. Note: despite the location of its antenna, the ADS-B receiver was not adversely affected by its proximity to the radar transmitter...... 18 Figure 16: Various perspectives of the MRL truck and its location relative to the runway shown in the Google Earth picture in the lower right. The red lines show the directions toward the Shirley’s Bay Campus (upper) and the Ottawa International Airport (lower). (Photos by the author) ...... 19 Figure 17: Kinetic SBS-1 ADS-B receiver and data logging system used to collect ground truth data during the trials at the GEA. The “Virtual Radar” display in the upper right corner shows some of the air traffic observed in the Ottawa area on 18 Sept. 2010 within a range of 209.5Nm. (Photos by the author) ...... 20 Figure 18: Beaver float plane (upper photo, with inset) and the corresponding radar track (bottom two images). The track in the radar display is a mosaic generated from multiple overlapping radar images (radar system operating in long range mode)...... 23 Figure 19: Track (lower images) of the Bell 206 helicopter shown in the upper photograph (with inset). The track in the radar display is a mosaic generated from multiple overlapping radar images (radar system operating in long range mode)...... 24 Figure 20: A Diamond DA-20-A1 Katana (based on wing ID, C-FWSH, in upper photo) and the corresponding radar track (bottom images). The track in the radar display is a mosaic generated from multiple overlapping radar images (radar system operating in long range mode)...... 25 Figure 21: Radar track (red ellipses) of a small aircraft (type unknown) landing at the Rockcliffe Airport on 6 Aug. 2010 at approximately 5 pm EDT. The maximum range where the aircraft was first detected was approximately 27km using the radar system’s long range mode...... 26 Figure 22: Small low-winged aircraft tracked to a range of just over 13.8km with the radar in Long Range mode...... 28 Figure 23: Three photographs of the Beech twin engine aircraft at the air show plus a similar aircraft (lower right) in flight. The two in the upper row were taken by the author at the air show (just prior to the radar sequence in Figure 24) and the lower left is courtesy of Adam Mooz (www.flickr.com/photos/adammooz/5038812759)...... 29 viii DRDC Ottawa TM 2013-152

Figure 24: Tracking sequence of the low-winged Beech TC-45G “GTMO-Bay-086” (see Figure 23) while in Long Range mode, from take-off until the track was lost at 21.6 km. For this sequence, the aircraft’s aspect with respect to the radar antenna was tail-on and receding...... 30 Figure 25: Small single- engine low-winged Mooney 20E aircraft during take-off; photographed by the author. Although the initial direction was westward, it quickly made a clockwise turn and headed east...... 31 Figure 26: Screen captures of the radar display while tracking the Mooney 20E in Long Range mode. The most western arrow (N is 0°) in the image at 17:45:20 points to the aircraft echo before the tracker has locked on. The remaining three images show the aircraft track (#113) until it was lost just after reaching a range of 17.1 km...... 32 Figure 27: Several views of the PBY-5A Canso. The two photos in the upper row and at the bottom were taken by the author at the GAS, whereas the central image is from a book on World War II aircraft by B. Gunston [17]. The bottom photo also shows the Lancaster taking off behind the Canso...... 33 Figure 28: Series of screen captures of the radar display while tracking the PBY-5A Canso in Long Range mode as it left the air-show and flew westward until out of detection range at just over 30.3 km. The upper row show the display with the track markers displayed, whereas the bottom row shows the display at approximately the same time with the markers suppressed to allow the radar echo to be seen. For the track sequence shown here, the aircraft‘s aspect with respect to the radar antenna was tail-on and receding...... 34 Figure 29: Pictures of the Lancaster Mark X flying in formation with a Corsair during the WOG air show. The quality of the upper photo is somewhat degraded due to magnification and cropping of the original picture...... 35 Figure 30: Screen captures of the radar display in Short Range mode while tracking the Lancaster and Corsair flying in formation doing a circuit around the airport. The third image (lower left) shows two new aircraft joining the formation (note: track markers are turned off in some of the images)...... 36 Figure 31: Screen captures of the radar display comparing the resolution in all three modes: Short, Medium and Long. In Short range mode all five aircraft (Lancaster plus four fighter escorts) in formation can just be resolved, but in Long range mode all five aircraft merge into a single “blob”...... 37 Figure 32: Two dimensional plan view of the ADS-B tracks for 29 July 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential to be detected by the radar system are shown in colour, the others are in white...... 40 Figure 33: Three dimensional views of the 29July ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 45 km range “limit” indicated by the yellow cone and cylinder respectively...... 41 Figure 34: Two dimensional plan views of the ADS-B tracks for 30 July 2010 showing the (ICAO24) identity and Callsign of each aircraft. Only one track was not expected

DRDC Ottawa TM 2013-152 ix

to be detected by the radar, and it is shaded white in the upper image. Notice the 900 m offset for the blue track...... 42 Figure 35: Three dimensional views of the 30 July ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 45 km range “limit” indicated by the yellow cone and cylinder respectively...... 43 Figure 36: Two dimensional plan view of the ADS-B tracks for 6 August 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential to be detected by the radar system are shown in colour, the others are in white...... 44 Figure 37: Two 3Dl views of the 6 August ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 45 km range “limit” indicated by the yellow cone and cylinder respectively...... 45 Figure 38: The incorrectly reported track of a Korean Airlines (Republic of Korea) Boeing 777-2B5ER, flight KAL09, on 11 Aug. 2010 from 14:18:35 EDT to 14:36:42 EDT...... 47 Figure 39: Two dimensional plan view of the ADS-B tracks for 11 Aug. 2010 showing the (ICAO24) identity and Callsign of each aircraft. Only tracks from aircraft with the potential of being detected by the radar system are shown. Notice the significant error offset for the C01766_564 track (light blue, left of centre) compared to the C051E2_ACA889 (green) track...... 48 Figure 40: Three dimensional views of the 11 Aug. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam indicated by the yellow cone. The 40km range “limit” is omitted in these views to allow the tracks to be seen under the radar cone...... 49 Figure 41: Three dimensional views of the 11 Aug. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “limit” indicated by the yellow cone and cylinder respectively...... 50 Figure 42: Additional three dimensional views of the 11 Aug. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “limit” indicated by the yellow cone and cylinder respectively...... 51 Figure 43: Two dimensional plan view of the ADS-B tracks for 17 Sept. 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential of being detected by the radar system are shown...... 52 Figure 44: Three dimensional views of the 17 Sept. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “limit” indicated by the yellow cone and cylinder respectively. The 40km range “limit” is omitted in these views to allow the tracks to be seen under the radar cone. The look direction is provided by the compass in the upper right corner of each image...... 53 x DRDC Ottawa TM 2013-152

Figure 45: Three dimensional views of the 17 Sept. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam indicated by the yellow cone. The 40km range “limit” is omitted in these views to allow the tracks to be seen under the radar cone. The look direction is provided by the compass in the upper right corner of each image...... 54 Figure 46: Three dimensional perspective of the ADS-B tracks from aircraft in the vicinity of Ottawa International Airport and the Gatineau Executive Airport on 17 Sept. 2010. This view is looking toward the Northwest. The “silver” track is actually bypassing the OIA...... 55 Figure 47: Three dimensional perspective of the ADS-B tracks from aircraft in the vicinity of Ottawa International Airport and the Gatineau Executive Airport on 17 Sept. 2010. This view is looking toward the West...... 55 Figure 48: Three dimensional view overlooking the Ottawa International Airport from the perspective of aircraft approaching a landing from the Southwest. ADS-B reports from all of the aircraft except one (green) are aligned with their respective runways...... 56 Figure 49: Three dimensional view overlooking the Ottawa International Airport from the perspective of an aircraft approaching a landing from the Southeast on 17 Sept. 2010...... 56 Figure 50: Two dimensional plan views of the ADS-B tracks for 18 Sept. 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential of being detected by the radar system are shown. The lower image is an expanded view of the area centred on the OIA...... 57 Figure 51: Three dimensional views of the 18 Sept. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “limit” indicated by the yellow cone and cylinder respectively. The 40km range “limit” is omitted in these views to allow the tracks to be seen under the radar cone. The look direction is provided by the compass in the upper right corner of each image ...... 58 Figure 52: Additional three dimensional views of the 18 Sept. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “limit” indicated by the yellow cone and cylinder respectively...... 59 Figure 53: Three dimensional views of the 18 Sept. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam indicated by the yellow cone. The 40km range “limit” is omitted in these views to allow the tracks to be seen under the radar cone...... 60 Figure 54: Some offsets may occur between the ADS-B reported range and the Radar range when plotting the results on a map if all of the geometry is not accounted for. The latitude and longitude of the aircraft is projected to the surface directly beneath it, whereas the location based on the radar range and azimuth approximates R0 by using Rt...... 61

DRDC Ottawa TM 2013-152 xi

Figure 55: Comparison of corrupted radar data collected on the 29 July (left) with good data collected on 30 July (right) 2010. The corrupted data sectors (outlined in red) were not stationary, but varied in an apparently random fashion with respect to width, number and direction. The precise origin of the corruption was uncertain...... 63 Figure 56: ADS-B (blue) and radar tracks (red) for an Air Canada Boeing 767-375 observed landing at Ottawa International Airport on 30 July. 2010. The radar tracked it between 16:23:39 EDT and 16:29:04 EDT to a maximum range of about 27.2 km. .. 64 Figure 57: ADS-B (yellow) and radar tracks (red) for an Air Canada Airbus A330-343X observed landing at Ottawa International Airport on 30 July. 2010. The radar tracked it between 15:28:47 EDT and 15:35:55 EDT to a maximum range of about 38.7 km...... 65 Figure 58: ADS-B (light blue) and radar tracks (red) for an WestJet Boeing 737-7CT/W observed taking off from Ottawa International Airport on 30 July. 2010. The radar tracked it between 14:53:16 EDT and 14:56:32 EDT to a maximum range of about 23.8 km...... 66 Figure 59: ADS-B (blue) and radar tracks (white) for a WestJet Boeing-737-6CT observed landing at Ottawa International Airport on 6 Aug. 2010. The radar tracked it between 16:44:06 and 16:50:07 to a maximum range of about 44.7 km. The other tracks are of ADS-B reports from aircraft that weren’t detected by radar...... 67 Figure 60: ADS-B (red) and radar tracks (light blue) for an Air Canada Boeing-767-38E (ER) observed landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 15:27:33 and 15:34:20 to a maximum range of about 39.0 km. In this case the ADS-B track had offset errors of 12 km to the East and 1 km to the South. The green arrow shows the direction to, and orientation of, the runway...... 68 Figure 61: ADS-B (red) and radar tracks (light blue) for an Air Canada Airbus A330-343 observed landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 15:18:24 and 15:29:34 from a maximum range of about 40.1 km...... 69 Figure 62: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 17:39:22 and 17:45:27 from a maximum range of about 40.2 km...... 70 Figure 63: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-6CT observed landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 16:45:33 and 16:48:35 from a maximum range of about 39.3 km...... 71 Figure 64: ADS-B (red) and radar tracks (light blue) for an Air Canada Boeing-767-38E (ER) observed taking off from Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 17:26:39 and 17:32260 to a maximum range of about 39 km...... 72 Figure 65: ADS-B and radar tracks for an Air Canada Boeing-767-375(ER) (ID: C0054A) and a WestJet Boeing 737-7CT (ID: C0669E) on 17 Sept. 2010. The AC and WJ flights were tracked to a maximum range of 29.5 and 28 km respectively...... 73 Figure 66: Additional radar tracks detected but not associated with any ADS-B reports recorded on 17 Sept. 2010. The maximum detected range of any of the aircraft xii DRDC Ottawa TM 2013-152

was 48.9 km but since there was not an associated ADS-B track there was no altitude or identification information...... 74 Figure 67: ADS-B (red) and radar tracks (light blue) for an extended range (ER) Boeing-767- 35H from Ireland (Centennial Aviation) tracked by radar for a brief period between 13:55:21 and 13:56:10 at a range of about 40 km on 18 Sept. 2010...... 76 Figure 68: ADS-B (red) and radar tracks (light blue) for a United Airlines extended range (ER) Boeing-767-322 tracked by radar for a brief period between 14:27:12 and 14:27:50 at a range of about 47 km on 18 Sept. 2010...... 77 Figure 69: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport between 18:53:17 and 18:56:34 on 18 Sept. 2010. The maximum observed radar range was just over 39 km...... 78 Figure 70: ADS-B (dark blue) and radar tracks (red) for a WestJet Boeing-737-7CT/W observed landing at Ottawa International Airport between 17:29:43 and 17:38:37 on 18 Sept. 2010. The maximum observed radar range was 26.3 km. The small circle in the lower image identifies where and when the Rutter 100S6 alpha-beta tracker had difficulty maintaining a lock on a high speed target making a rapid manoeuvre...... 79 Figure 71: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 17:04:02 and 17:07:44 and to a maximum range of about 42.8 km...... 80 Figure 72: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 14:17:47 and 14:19:47 and to a maximum range of about 30.9 km...... 81 Figure 73: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 18:01:23 and 18:04:23 to a maximum range of about 38.6 km .... 82 Figure 74: ADS-B (blue) and radar tracks (white) for an Air Canada Boeing-767-35H (ER) observed taking off from Ottawa International Airport on 18 Sept. 2010. Except for a brief gap (17:37:44 to 17:38:51) the radar tracked it between 17:34:47 and 17:40:40 at a maximum range of about 35.7 km. The gap is probably due to the aircraft being outside the radar’s main beam...... 83 Figure 75: Google Earth views showing where the flight path of the Boeing-767-35H (ER) shown in Figure 74 intersects with the nominal 12° cone swept by the radar beam. .. 84 Figure 76: Flight path (red dashed line) of Air Canada flight 838 (ID: C0584D) relative to the ground clutter in the vicinity of the radar site. The range rings in the image are at increments of 8 km...... 84 Figure 77: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 14:48:57 and 14:52:26 to a maximum range of about 33.6 km .... 85

DRDC Ottawa TM 2013-152 xiii

Figure 78: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-6CT observed for a brief period from 14:34:31 to 14:35:43 on 18 Sept. 2010 at an average range of about 50 km. The aircraft’s probable destination was Montreal...... 86 Figure 79: Miscellaneous radar tracks recorded for 18 Sept. 2010. None of these tracks had an associated ADS-B track so they could not be identified. The maximum range of any detected aircraft was 42.1 km...... 87 Figure 80: ADS-B reports from commercial passenger flights over the Gascoyne Inlet area in Aug. 2008...... 90 Figure A-1: Basic structural elements for estimating an aircraft RCS (not in order of importance). The RCS of a sphere (not shown) is RCS=πD2/4 where D is the diameter and is independent of angle and frequency. Trihedral corners were not expected in an aerodynamic airframe, so were not included...... 95 Figure A-2: Measurements for the Boeing 737-600 passenger aircraft leading to the RCS estimates listed in Table A-.The areas outlined in white show how the RCS elements relate to the actual airframe (nose, wing edges, and engines omitted)...... 96 Figure A-3: RCS model for the B737-600 showing the elements listed in Table A-...... 97 Figure A-4: Measurements for the DHC-6 Twin Otter that lead to the RCS estimates provided in Table A-2. The areas outlined in red show how the RCS elements relate to the actual airframe (nose, wing edges, and engines omitted)...... 98 Figure A-5: Radar Cross Section of a MIG-29 at near nose-on aspect. The images on the left are CAD model perspectives at zero degrees azimuth and a pitch of 0 and five degrees respectively. The plots on the right are the respective RCS predictions from FACETS as a function of azimuth. The jet engine intakes at nose on increases the RCS by at least 10 dBsm ...... 99 Figure B-1: Typical set of parameters for running SIESTA; unless the “ASL” box is checked, the software assumes the antenna height is with respect to the terrain height for that geographic location (latitude and longitude)which, for this specific location on top of Cape Liddon, was about 300m ASL. Also, for the scenarios used in this report, the METEO data, including the HPAC file were not available, and did not factor into the calculations...... 102 Figure B-2: This is an example of the “RF Situational Display Main Control Panel” where additional set-up parameters such as CAPPI height (i.e. “Height ASL”) are input to SIESTA. The image on the extreme right is a “thumbnail” of the terrain elevation (obtained from Digital Terrain Elevation Data (DTED) or Canadian Digital Elevation Data (CDED) files) centred on the specified “RADAR LOCATION”. In general, darker colours represent lower altitudes, with blue representing the ocean, and “red-hot” representing the highest altitudes...... 103 Figure C-1: Photographs of two aircraft observed on 30 July 2010: a Beaver float plane in the upper left, and a fly-over by a Piper Cherokee...... 110 Figure C-2: Photographs of aircraft observed between 9:42:53 and 14:49:25 on 6 Aug. 2010. . 111 Figure C-3: Photographs of a Bell 206A JetRanger helicopter in the vicinity of the GEA throughout the day on 6 Aug. 2010...... 112 xiv DRDC Ottawa TM 2013-152

Figure C-4:: Photographs of aircraft observed between 13:25:34 and 17:39:30 on 11 Aug. 2010...... 113 Figure C-5: Photographs of aircraft observed between 14:17:58 and 14:47:44 on 17 Sep. 2010. This included several photos of a T33 Turbo Jet during flyovers...... 114 Figure C-6: Photographs of aircraft observed between 14:48:03 and 14:51:31 on 17 Sep. 2010 115 Figure C-7: Photographs of aircraft observed between 14:52:19 and 17:46:56 on 17 Sep. 2010...... 116 Figure C-8: Photographs of aircraft observed between 17:47:23 and 17:56:12 on 17 Sep. 2010...... 117 Figure C-9: Photographs of aircraft observed between 18:32:09 and 19:15:58 on 17 Sep. 2010...... 118 Figure C-10: Photographs of aircraft observed between 13:53:20 and 14:34:25 on 18 Sep. 2010 ...... 119 Figure C-11: Photographs of aircraft observed between 14:47:017and 15:11:11 on 18 Sep. 2010 ...... 120 Figure C-12: Photographs of aircraft observed between 15:16:35 and 15:29:01 on 18 Sep. 2010. Most of the photos were of an F86-E Sabre jet except for the one in the upper left where it was flying in formation with a T33 Shooting Star and the second photo of the T33 in the bottom row...... 121 Figure C-13: Photographs of aircraft observed between 15:31:16 and 15:58:408on 18 Sep. 2010. The aircraft included an F86-E Sabre Jet, a Lancaster Mark X bomber and a PBY-5A Canso...... 122 Figure C-14: Photographs of aircraft observed between 15:58:31 and 16:41:32 on 17 Sep. 2010. The aircraft included a Corsair, and a Lancaster flying separately and in formation with other WW II fighters...... 123 Figure C-15: Photographs of aircraft observed between 16:45:00 and 17:29:10 on 18 Sep. 2010 ...... 124 Figure C-16: Photographs of aircraft observed between 17:29:22 and 17:38:44 on 18 Sep. 2010 ...... 125 Figure C-17: Photographs of aircraft observed between 17:38:40 and 17:42:47 on 18 Sep. 2010 ...... 126 Figure C-18: Photographs of aircraft observed between 17:42:51 and 17:45:56 18 Sep. 2010 .. 127 Figure C-19: Photographs of aircraft observed between 17:46:06 and 17:48:08 on 18 Sep. 2010 ...... 128 Figure C-20: Photographs of aircraft observed between 17:48:11 and 18:31:51 on 18 Sep. 2010 ...... 129

DRDC Ottawa TM 2013-152 xv

List of tables

Table 1: Relative dimensions of the Twin Otter and B-26 dimensions...... 12 Table 2: List of Airports and Aerodromes in the Ottawa-Gatineau area...... 17 Table 3: Radar and ADS-B data collected between 29 July and 18 Sept...... 20 Table 4: Aircraft types observed and recorded by ADS-B within 50 km of the Gascoyne Inlet test site during field trials in 2008 ...... 90 Table A-1: Elements contributing to a rough estimate for the RCS of a Boeing 737-600 ...... 97 Table A-2: Elements contributing to a rough estimate for the RCS of DHC-6 Twin Otter ...... 98 Table B-3: System Description ...... 101 Table B-4: Mechanical Dimensions: ...... 101 Table C-1: List of aircraft observed visually, and photos collected, to ground truth the radar data recorded during the trials. Aircraft types were often confirmed by looking up the wing number in internet databases (provided in the last column); otherwise, a best guess was used...... 104 Table D-1: Specifications for aircraft observed during the GEA trials, as well as some “Arctic” aircraft ...... 130

xvi DRDC Ottawa TM 2013-152

Acknowledgements

The author would like to acknowledge the valuable contributions made by Mr. D. Lamothe and Mr. G. Duff to ensure the successful completion of these trials. Without their assistance, and useful ideas (especially Mr. Lamothe), these trials could not have taken place. Mr. Duff’s photographic record of the trials was a valuable addition to the one collected by the author.

The author would also like to thank Dr. Silvester Wong for generating the RCS plot of the MIG- 29 using FACETS.

DRDC Ottawa TM 2013-152 xvii

This page intentionally left blank.

xviii DRDC Ottawa TM 2013-152

1 Introduction

In April 2007 the Northern Watch (NW) Technology Demonstration Program (TDP) Project was given initial approval to begin implementation. The original focus of this project was to show how a suite of underwater (UW) sensors and land-based above-water (AW) sensors could be integrated and used to provide enhanced surveillance of a maritime choke point as part of a layered surveillance capability. The sensors were primarily chosen based on cost estimates and pre-trial assessments of their complementary abilities to detect, track, classify, and possibly identify maritime surface or subsurface vessels as well as the potential to provide limited surveillance of aircraft. The sensors and systems that were chosen to be part of the overall sensor suite were as follows:

 Automatic Identification System (AIS) Receiver – a VHF line of sight (LOS) self reporting anti-collision system for sea going vessels over 300 tons, as well as commercial passenger vessels of any size. The system was implemented as part of the SOLAS (Safety Of Life At Sea) convention. Ships equipped with AIS transceivers continuously broadcast their location (usually based on navigation data provided by a Global Positioning Satellite (GPS) receiver system) to other vessels in the area, as well as such other information as heading, speed, rate of turn, point of departure and destination, ship type and dimensions, and occasionally their cargo (especially if it consists of dangerous materiel).

 Low-cost X-band Navigation Radar System- for reasons that will be explained later, the project decided to purchase a fairly high power (25 kW peak power) low-cost X-band (9.41 GHz) non-coherent navigation radar system as part of the surveillance suite. The radar that was purchased—as a result of open tendering—was the Rutter 100S6 Navigation Radar system. The specifications for this system are provided later in this document.

 Electro-optic/Infrared (EO/IR) Imaging System – In order to provide truly unambiguous information as to the class or identity of a non-cooperative surface vessel or aircraft, an imaging system is required. The Canadian Arctic Night-and-Day Imaging Sensor System (CANDISS) was developed based on requirements specified by project scientists at DRDC-Valcartier. It consists of a suite of integrated imaging sensors including a wide field of view (WFOV) colour camera, and a narrow field of view system incorporating a thermal imager, and an active laser imager.

 Radar Interception and Identification System – A receiver system was developed by scientists at DRDC Ottawa (led by Dr. J. Lee) that is capable of intercepting radar system transmissions from ships and identifying the direction of the signal, the radar type and possibly the associated vessel platform.

 Under Water Sensor (UWS) system – As part of a previous TDP project, a UWS named the Rapidly Deployable System (RDS) was developed by a team (led by Dr. G. Heard) at DRDC Atlantic to provide surveillance of surface and sub-surface vessels. The system consisted of arrays of acoustic, electric and magnetic sensors connected to a “backbone” cable which provided power to the sensors and a communication conduit back to a

DRDC Ottawa TM 2013-152 1

processing computer that could be located on a ship or on shore. This system, which was originally intended for temporary deployments, was modified for the NW project so that it would survive in the Arctic for longer term installations, and for colder temperatures.

 Automatic Dependent Surveillance-Broadcast (ADS-B) – Similar to AIS, this is a self- broadcasting system for collision avoidance that is becoming standard on most long distance (usually over 3 hour) international commercial air passenger flights. It is based on the Mode-S information transmission protocol originally proposed for Secondary Surveillance Radar (SSR) used by civilian Air Traffic Control (ATC) systems at larger airports. The military equivalent of SSR is the Identify Friend or Foe (IFF) system; both systems are interoperable. Unlike the IFF and SSR transponder systems that require an interrogation system (usually on the Earth’s surface) and a corresponding responder transceiver system on the aircraft, ADS-B systems continuously broadcast their location to other receivers (air or ground). These systems have a much higher reporting rate than AIS due to the greater speed and manoeuvrability of aircraft. Some of the important information that is embedded in the Mode-S message are the International Civil Aviation Organization’s 24 bit (ICAO24) hex identifier code (a 6 digit alphanumeric code unique to each aircraft, referred to as the ID throughout this report), the aircraft’s Callsign (often related to the flight number), geographic location (GPS latitude and longitude), altimeter altitude, aircraft speed and heading. The ICAO24 ID can be used to identify the country of origin (e.g. ID numbers beginning with C in the range C00000 to C40000 belong to Canadian aircraft).

While the main purpose of the Rutter 100S6 Navigation Radar system is to provide an all-weather sensor to detect and track both cooperative and non-cooperative surface vessels (e.g. any ships not providing AIS reports or emitting “trackable” radar signals), it might also be capable of limited surveillance of low-flying aircraft. In order to determine its effectiveness for detecting and tracking such aircraft, experimental trials were performed in the Ottawa-Gatineau area at the Gatineau Executive Airport (GEA) during the late summer of 2010 .The purpose of this report is to describe the planning, set-up, execution, analysis and results of these experimental trials.

Throughout this report, units may alternate between SI and Imperial for two reasons: 1) because the original source’s units were not converted; or 2) because Imperial units are still accepted internationally for describing certain aircraft parameters. For example speeds are often provided in terms of knots (1knot=1.852 kph), and altitudes are often expressed in terms of feet above sea level.

The remainder of the report will be divided into four sections: a) radar performance prediction for air targets; b) trials planning, set-up and execution; c) analysis and results; and d) conclusions.

2 DRDC Ottawa TM 2013-152

2 Radar System Performance Prediction for Aircraft

The primary intent of this section is to provide qualitative and quantitative arguments to support the belief that the Rutter 100S6 could potentially provide a limited air surveillance capability for monitoring arctic airspace. Although the physical characteristics of the area surrounding Cape Liddon, and those of the land in the Gatineau Executive Airport (GEA) area are markedly different, some conclusions drawn in this section are applicable to both locations. The main differences between the two locations are that Cape Liddon consists of mostly barren rocky soil overlooking the waters of Barrow Strait, whereas the GEA area lacks any wide expanses of water, and is mostly land with vegetation cover, bordered by some residential areas to the South.

Although the area of interest in this section is focused on the vicinity of Cape Liddon, which is on the southwest corner of Devon Island, many of the results can be generally applied to other areas.

The types of aircraft that are expected to fly through arctic airspace will generally fall into two categories:

1) Small to medium-sized low-flying (below 12500 ft) aircraft typically the size of a DHC-6 Twin Otter (Figure 1 top row), or smaller, and

2) Commercial airliners the size of an ATR42 (Figure 1 bottom row) or larger, that have typical cruising altitudes of 25000 ft or higher. Many of the larger aircraft are large trans- polar commercial airliners typically larger than, a Boeing 737 with normal cruising altitudes of 35000 ft to 40000 ft. While commercial airliners aren’t normally considered as “low-flying”, an emergency situation might force such an aircraft to fly at lower altitudes, especially if it was required to make a forced landing.

DRDC Ottawa TM 2013-152 3

In order to set up the discussion on radar performance prediction, it is appropriate to briefly review the physics and typical characteristics of the system in question. The physics of the system are embodied in one form of the well-known radar equation for a monostatic radar system that is given by equation (1).

422 GP tt σλ F Pr  (1)  3 R4π 4

In this equation “Pt” is the transmit power (at the antenna), “Pr” is the received power (at the antenna), “Gt” is the antenna transmitter gain, “λ” is the radar signal wavelength, “σ” is the target’s radar cross-section (RCS), “R” is the distance between the radar antenna and the target, and “F” is the “pattern propagation factor”. The pattern propagation factor is defined in [1] as the ratio of the electric field of the radar system’s radio frequency carrier signal, at a given point under specified conditions, to the amplitude of the same electric field if it were under free space conditions.

Arguably, the four most influential factors affecting the ability of the 100S6 to detect any aircraft are the radar system’s effective radiated power, its receiver sensitivity, the aircraft’s RCS profile (i.e. function of azimuth and elevation), and the radar antenna-to-target geometry (including the aspect angle of the aircraft). With regard to the geometry, the aircraft should be within the main beam of the radar (i.e. 3dB beamwidth) in order to have a reasonable chance of being detected at any significant distance.

As Briggs states in his book, “Target Detection By Marine Radar” [2], radar manufacturers seldom provide specifics of their radar system’s elevation beampattern; however, it is reasonable to assume that, since the antenna of the Rutter 100S6 is a slotted waveguide (linear) array, the 2 antenna gain will follow the familiar |(sin x)/x| pattern where x=k∙sin(el) and el is the 3 dB elevation beamwidth . For a 3 dB beamwidth of 24° the elevation beampattern (using k= 6.7) of the 100S6 is probably similar to that shown in Figure 2.

Figure 2: Assumed vertical antenna gain for the Rutter 100S6 based on a 3 dB elevation 2 2 beamwidth of 24° and a typical beampattern of sin x/x (x=6.7 sin(el)) associated with a rectangular aperture. (Note: the importance of the intersection point at 37° will be made apparent later in Section 4.2.4.)

4 DRDC Ottawa TM 2013-152

This means that if the Rutter 100S6, with an antenna elevation beamwidth of 24° (12° on either side of the antenna’s horizontal bore-sight) was located near sea level (as in Figure 3), it would require a target at a range of 20 km to be flying at an altitude of less than 4200 m (13800 ft) above sea level (ASL) in order to be detected. This is a reasonable assumption for Twin Otter flights based on the author’s experience. For example, during clear-weather Twin Otter flights between Resolute and Cape Liddon, experienced by the author in July 2007 and in August 2008, the pilot maintained a cruising altitude of less than 1000 m ASL. A typical altitude was usually about 200 m to 300 m above the surrounding terrain that was usually less than 300 m ASL (i.e. for Cornwallis Island and the SW corner of Devon Island). At a range of 40 km, the corresponding maximum altitude that would still be in the antenna’s main beam would be less than 9000 m or under 30000 ft. As will be shown later, only large aircraft, such as long-haul airliners, with a large RCS can be expected to be detected at such ranges.

Figure 3: Geometry of a low flying aircraft with respect to a Rutter 100S6 radar if placed on top of Cape Liddon at an altitude of 320 m above sea level (ASL).

The arguments in the previous paragraph were made by assuming that coherent specular multipath interference could effectively be ignored. This is a reasonable assumption for air targets over land, at grazing angles usually greater than 1°. As discussed by Meek [3], in such a situation the effects of multipath interference due to specular reflection will be greatly reduced because of the lower reflection coefficient of terrain and vegetation, as well as the effects of surface roughness that cause diffuse (i.e. random) reflections to dominate. On the other hand multipath due to reflections from water surfaces, especially during relatively calm conditions, may have a significantly greater effect because of the high reflection coefficient of water. In such cases, for a point target, the strength of the echo will be modulated by a “pattern propagation factor” that traces out a series of peaks and nulls as a function of range and target altitude (assuming constant antenna height) due to constructive or destructive interference. As will be shown later, in an open water setting this presents itself in a radar coverage diagram or Constant (target) Altitude Plan Position Indicator (CAPPI) plot as a series of rings indicating that a target would have either enhanced or reduced ability to be detected. It can easily be shown, using a few simplifying assumptions (e.g. such as assuming a flat Earth, and an omnidirectional antenna as shown in Figure 4) that the pattern propagation factor (F) due to specular multipath interference can be approximated by equation (2). In the definition of F used here, the amplitude of electric field of

DRDC Ottawa TM 2013-152 5

the radar signal is attenuated by a factor F on its way to the target and another factor of F when the reflected target echo reaches the radar receiver, for an overall attenuation of F2. To get the power attenuation, this factor is simply squared (i.e. F4).

In the derivation of equation (2) based on the geometry of Figure 4, the fact that the E field is horizontally polarized simplifies the addition of the two vector components, ED and EI so that they can be treated like complex scalar values. Also, it is assumed that rI≈rD.

Figure 4: Geometry and assumptions used to estimate the pattern propagation factor, F, for the radar equation. Here E is the electric field vector for a horizontally polarized radar signal, rD is the length of the direct signal path, rI is the length of the reflected signal path, ρ is the reflection coefficient,  is the phase change on reflection, Ro is the target’s horizontal range, h is the antenna height and z is the target height.

2 kzh F [1  cos(ρ2ρ )]1/2 (2) R

In equation (2), “ρ” is the reflection coefficient, “z” is the height of the target, “h” is the height of the antenna, “” is the phase change induced in a ray reflected from a surface, k=2/ where  is the radar wavelength, and “R” is the horizontal range to the target. It can be seen in equation (2) that maxima occur when equation (3) holds true.

2π zh 2nπ   1,2,...n; (3) λ R

Based on the realistic assumption that the maximum value of || is unity, then the maximum possible value of F in equation (2) is 2.0. Therefore the largest possible contribution from these constructive interference maxima to the radar’s received echo power is 24 or 12 dB.

6 DRDC Ottawa TM 2013-152

Assuming that only the range changes while all other values remain constant, then the separation between adjacent maxima is given by equation (4)

2 zh 2 R   1,2,...n; (4)  )(2(n-(2n 1)  )-

If the phase change upon reflection is assumed to be π, which is almost true for reflections of horizontally polarized signals from a smooth water surface, then equation (4) simplifies to:

zh 14 R   1,2,...n; (5)  n2 -4( 1)

Examples of the propagation factor for two values of target height and two values of ρ, based on equation (2), are provided in Figure 5. It can easily be seen that the enhancement factor for the received power can be as large as a factor of 16 (i.e. 24, or 12 dB) for a reflection coefficient close to unity. Also, for large values of antenna and target height, the separation between adjacent maxima becomes small enough to look like a continuum. This effect can be seen in Figure 5 as well as later in Figure 11.

Figure 5: Pattern Propagation Factor “F” for four different scenarios. On the left, the antenna and target heights were 10m and 100m respectively, with the blue and black curves representing reflection coefficients of 0.9 and 0.3 respectively. On the right, the same reflection coefficients were used but the antenna and target heights were changed to 50m and 400m respectively.

2.1 Monostatic RCS Estimates

In general the monostatic RCS profile of any aircraft is quite complex. It depends on the frequency and polarization of the electromagnetic wave impinging on the airframe, and is a coherent sum of reflecting/scattering contributions from all surfaces, edges and vertices “seen” by the radar system. As pointed out by Lynch [4]and Fuhs [5], the largest contributions to the RCS are usually due to single or multiple bounce specular (mirror-like) reflections from surfaces

DRDC Ottawa TM 2013-152 7

associated with the wings, fuselage or engines. Usually of less consequence are the contributions due to some edges and vertices that are the result of diffraction or due to a radar beam at low incident angle inducing travelling waves on the surface of the airframe which radiate back into space after meeting a discontinuity. These observations are reflected in the RCS profile example shown in Figure 6 for a one-fifteenth scale model of a Boeing 737 that was originally published by Howell in 1970[6], and subsequently included in publications by Schleher 1999[7], and Yildirim 2008[8]. The profile was generated by using a vertically polarized radar beam and operating at a frequency of 10 GHz.

Figure 6: Measured backscatter (RCS) from a one-fifteenth scale model of a Boeing 737 at 10 GHz, vertical polarization [6][7][8]. This is equivalent to a radar frequency of 667MHz for a full scale aircraft.

Based on the example shown in Figure 6, it can be seen that the largest contributions (dominant scatterers) to the aircraft’s RCS profile are usually due to large scale structures like the fuselage, wings, and engines. These contributions to the RCS are mostly due to specular reflections and are the easiest to model using Physical Optics.

While a number of software suites such as XPATCH (Hazlett et al 1995[9]), RAPPORT (Radar- signature Analysis and Prediction by Physical Optics and Ray Tracing, Brand 1995[10],) and FACETS/FEMAS (described in a report by Wong 2009 [11]) have been developed to generate high fidelity RCS profiles of objects based on models of their three dimensional structure (e.g. computer-aided design or CAD models), the amount of effort required to construct such models and generate their RCS profiles is beyond the scope of this report. However, to provide a rough estimate of the maximum RCS that might be attributable to a specific airframe, it is possible to decompose the structure into a set of simple shapes with known RCS profiles. For example an airframe observed at an elevation angle of close to 0°, and assuming a role, and pitch also of 0°, might be crudely represented by a set of cylinders of different length and diameter to represent the fuselage, flat rectangular plates for the vertical stabilizer wing, a combination of a right

8 DRDC Ottawa TM 2013-152

circular cone and hemisphere to represent the nose-cone, and edges for the wings as seen horizontally. Some results associated with specific classes of surface shapes are provided in Annex A for simple models based on the Boeing 737-600 and the DHC-6 Twin Otter.

It should be noted that the individual contributions to the RCS from most of these large scale structures are highly aspect dependent, tending to fall off rapidly at small angles from the direction of the surface normal. That is why they are referred to as “flashes” in Figure 6. For example, based on the example of a Boeing 737 shown in Annex A, the angular dependence of the contribution from the “main” portion of the fuselage modelled on a cylinder of radius 2.73m and length 19.43 m might look like the multi-lobed example shown in Figure 7.

Figure 7: Contribution to the RCS profile of a Boeing 737-600 based on a cylindrical model for the main portion of the aircraft fuselage. The plot on the right is an expanded portion of the image on the left.

As shown in Annex A, the largest contributor to the RCS for the Boeing 737-600 and the DHC-6 Twin Otter, at broadside, is the vertical stabilizer wing which has a maximum amplitude of 71.6 dBsm or 58.5 dBsm in the two respective cases. However, like the fuselage, the RCS due to this structure is highly aspect dependent, but less easily modelled since it is not a simple rectangle.

Other large contributors to the RCS profile are the dihedral corners formed between the wings and the fuselage. These structures will have a dependence on azimuth similar to that shown in Figure 8.

DRDC Ottawa TM 2013-152 9

Figure 8: Azimuth dependence of the dihedral corner formed by the main wing joining the fuselage, based on the simple model shown in Annex A. In most instances, this dihedral wouldn’t be visible to the radar unless the B-737 made a banking turn such that the upper surfaces of the airframe faced the antenna.

From directly in front of, or from behind, the aircraft, most reflections of any consequence tend to be from surfaces or edges with a normal vector directed toward the radar antenna’s aperture. This includes such structures as ailerons, flaps, elevators, wing edges, propulsion system surfaces (e.g. engine cowlings, and propellers or turbine blades), and the visible portion of the cockpit/nosecone.

While the actual RCS profile of the Twin Otter is not known, it is expected, based on its dimensions (Table 1) and the results of Annex A, to be similar to that of a full-scale B-26 Marauder—a two-engine medium-bomber aircraft used in World War II. The RCS profile of the B-26 Marauder (from Ridenour 1947 [12] and reproduced in Skolnik’s Radar Handbook [13]) for a radar frequency of 3 GHz, and as a function of azimuth angle, is shown in Figure 10 along with photographs comparing it to the Twin Otter. As implied by the B-26 RCS profile, the radar echo is usually stronger at broadside because of reflections from the fuselage, the vertical stabilizer wing and the greater tendency to see dihedral corner reflections (e.g. where wings or engine nacelles meet the fuselage). This is especially true for high-winged aircraft like the Twin Otter. As indicated by Figure 9, at broadside a true dihedral corner reflector has a tendency to act as a retro-reflector. While a trihedral corner reflector, also shown in Figure 9, is less affected by changes in azimuth, there are few examples of these structures on an aerodynamic airframe. Figure 9 also shows how a dihedral corner would be created on a high-winged airframe like the Twin Otter.

10 DRDC Ottawa TM 2013-152

Figure 9: Examples of a dihedral and trihedral corner reflector are shown in the upper frame. The areas where the aircraft wings meet the fuselage, as shown in the stylized air frame at the bottom, are examples of a dihedral corner reflector.

As shown in Figure 10 the maximum RCS from a B-26 at broadside for 3GHz is about 32 dBsm. If one assumes a similar RCS at X-Band (e.g. 9.41 GHz), then an estimate can be made of the maximum detection range that such an aircraft could be seen using the Rutter 100S6, depending on the geometry. This assumption seems reasonable if one simply scales the example shown in Figure 6 to the size (i.e. length, “L”) of the Marauder. This would give a broadside RCS at 10GHz of approximately 34dBsm as shown by equation (6).

LMarauder RCS(Marauder, broadside)  RCS(737model, broadside) 20  10 .)(log L737mod el  17.75m   RCS(737model, broadside) 20  log  . (6) 10 31 /m 15   RCS(737model, broadside) 18 7.  34dBsm

Based on the specifications of the Rutter 100S6 (using a Sperry BridgeMaster transceiver) and a specific environmental scenario (i.e. terrain altitude, land coverage, wind-speed, wind direction, sea state, air and sea temperature, etc. ) provided in Annex B, a radar coverage plot or CAPPI plot, of the minimum detectable target RCS as a function of range and azimuth was generated.

DRDC Ottawa TM 2013-152 11

The CAPPI plot was generated using the “RF”1 component of software developed in-house at DRDC called the Scenario2 Integrated Environment System (software) for Tactics and Awareness (SIESTA). Figure 11shows the minimum detectable RCS predicted by SIESTA as a function of range and azimuth for an aircraft flying at 400 m ASL in the vicinity of a radar system placed on top of Cape Liddon at about 300m ASL. The scenario also assumed that the aircraft acts like a point target. At 400m altitude an aircraft would be at an elevation roughly aligned with the boresight of the radar antenna. The cross, shown at a range of 33 km, represents the best predicted range for detecting an aircraft about the size of a DHC-6 Twin Otter, based on the RCS estimated from an aircraft of similar size (e.g. a B-26 Marauder bomber). Some of the ring structure associated with multipath mentioned earlier in this section can be seen in the plot. However, as was also mentioned, for such high antenna and target altitudes, this ring structure appears as a virtual continuum so that it is difficult to discern the difference between the peaks and nulls.

Another example from SIESTA is shown in Figure 12 where the radar antenna is located on a ridge at about 100 m ASL, in the valley of Gascoyne Inlet, adjacent to Cape Liddon. Because of the lower antenna altitude, the ring structure due to multipath is much more evident, even though the field of view is more restricted by the terrain.

Table 1: Relative dimensions of the Twin Otter and B-26 dimensions.

Aircraft Type Length Wingspan Wing Area Height (ft/m) (ft/m) (ft²/m²) (ft/m) Twin Otter (DHC-6 300 series) 51.75/15.77 65/19.8 420/39.0 19.5/5.94

Martin B-26 Marauder Bomber 58.25/17.75 71/21.64 658/61.13 21.5/6.55

Figure 10: The DHC-6 Twin Otter shown in the lower right is a typical size expected for low flying aircraft in the Arctic. While its RCS profile is not known, it is expected, based on its dimensions, to be similar to that of the B-26 Marauder [12][13]shown on the left.

1 The RF component of SIESTA was developed by Dr. A. Thomson at DRDC Ottawa. 2 An earlier version of SIESTA was the Shipborne Integrated Environment… until it was modified for land based systems

12 DRDC Ottawa TM 2013-152

Figure 11: SIESTA radar coverage prediction for low flying air contacts at altitudes of 400 m ASL (1300 ft). The cross at 33 km represents the maximum range for an aircraft the size of the B- 26 when it is broadside to the Rutter 100S6 radar beam.

DRDC Ottawa TM 2013-152 13

14 DRDC Ottawa TM 2013-152

3 Trials Planning, Setup, and Execution

The planning, setup and execution of the air surveillance trials were accomplished with minimal resources due to financial constraints that were imposed during the scheduled trials period. Some creative thinking was needed to identify a test plan that could provide useful radar data—with adequate ground-truthing—from a variety of low flying aircraft, but at a minimal expense. An ideal solution might have been to hire one or more small to medium sized piloted aircraft for short periods to fly prearranged flight paths, while recording their GPS reported location. However, this solution would probably have cost several thousand dollars and might have involved some logistical uncertainties. For example, scheduling delays due to adverse weather conditions, or other piloting issues, could negatively impact the trials execution by increasing costs. It was decided that a less expensive means to accomplish the objective would be to deploy the radar to somewhere in the Ottawa area to collect data from air traffic of opportunity. Ground-truthing the data would need to be accomplished using a combination of visual sightings and ADS-B reports, when available.

As listed in Table 2 and shown in Figure 13, the Shirley’s Bay campus of DRDC Ottawa is located in close proximity to a number of small airports and aerodromes that cater primarily to General Aviation (GA) aircraft. According to Transport Canada [14] this civil aviation category is a generic term that is associated with small to medium sized aircraft (e.g. small Cessna to Dash 8) used for non-military flights and air travel not related to scheduled airline or regular cargo flights, whether private or commercial. Also shown is the campus’ proximity to the Ottawa International Airport (MacDonald-Cartier) which supports regularly scheduled airliners, cargo flights and some military traffic. Most flights using this airport tend toward significantly larger aircraft than those associated with GA flights. Some basic statistical information on each of the sites is provided in Table 2. The directions, and distances to the four most important Ottawa area airports with respect to the DRDC Ottawa campus are shown in Figure 14. Based on this potential, it was felt that a rooftop site for the radar system at the Shirley’s Bay location might provide sufficient opportunities to observe both small and large aircraft.

The original concept was to mount the radar at an unobstructed site on a third story rooftop of one of the DRDC Ottawa buildings at the location shown in Figure 14. However, after some investigation, it was found that this option would be too expensive, and subject to operational constraints imposed by Site Antenna Committee (SAC) who are responsible for minimizing interference between RF systems on campus. An engineering study that was undertaken to determine the suitability of the proposed rooftop location determined that the cost of lifting and safely mounting the radar scanner into place would cost in excess of $7 k. These two issues made the Shirley’s Bay installation an unattractive solution.

DRDC Ottawa TM 2013-152 15

Figure 13: As shown in the above series of maps and aerial photographs from Google Earth, the Shirley’s Bay campus of DRDC Ottawa is within about 30 km to three small airports for small aircraft, as well as one large international airport.

16 DRDC Ottawa TM 2013-152

Table 2: List of Airports and Aerodromes in the Ottawa-Gatineau area. Airport/ Location Distance Distance Number Maximum Types of Surface Aerodrome Lat./Long. from from of Run- Runway Aircraft SBC GEA ways Length (km) (km) (m) Carp 45.321900°/ 11 40.9 2 1200 Small/ Pavement -76.022642° medium Rockcliff 45.457988°/ 22.6 8.2 1 1006 Small/ Pavement -75.643083° medium GEA 45.518932°/ 30.5 0 1 1830 Small/ Pavement -75.579108° medium Ottawa 45.322470°/ 17.5 23 4 3050 Large Pavement International -75.668852° Manotick 45.190556°/ 22.3 37.8 1 810 Small Turf (Hope Field) -75.708611° Embrun 45.239600°/ 47.3 37.7 1 1100 Small Turf -75.302330° Arnprior 45.413577°/ 38.3 62.6 2 1205 Small/ Pavement -76.367746° medium Pendleton 45.486484°/ 63.7 37.9 3 760 Small Pavement -75.095798° Gatineau 45.464444°/ 20.6 9.9 1 N/A Small Ottawa Water -75.680000° River Constance 45.402807°/ 9.2 33.5 1 N/A Small Constance Lake -75.974584 ° Lake

Figure 14: This aerial photograph from Google Earth shows where the radar system would have been located on the Shirley’s Bay campus of DRDC Ottawa if that plan had gone forward. It also shows the directions and distances to four local airports of greatest significance.

DRDC Ottawa TM 2013-152 17

A more attractive option was suggested by DRDC Ottawa technologist Mr. D. Lamothe. He suggested making minor modifications to Ottawa’s Mobile Radar Lab (MRL) to accommodate the Rutter radar system. The MRL is an air cushioned cargo truck (International 4700 T444E Box Truck) with a large 24 foot dry-cargo box modified to accommodate commercial-off-the-shelf (COTS) and experimental radar systems, support instrumentation, and personnel. A block diagram description of the MRL, as it was configured for the air surveillance trials, is shown in Figure 15 and photographs of the actual system are shown in Figure 16.

Since the MRL has its own diesel generator for electrical power, this solution would enable the radar system to be easily moved to, and tested at, multiple sites for little more than the cost of the diesel fuel. It also meant that the radar system could be easily relocated to remote sites where it would not interfere with other projects or activities. It would therefore be less vulnerable to inconvenient operational constraints that might be imposed at the Shirley’s Bay campus. In order to facilitate these trials, and ensure the timeliness of the results, the small costs of fuel and modifications for the MRL were absorbed by DRDC Ottawa.

While the modifications were being made to the MRL, Mr. Lamothe, with the agreement of the Lead Scientist (Mr. D. Brookes), took the initiative to approach the various small airports in the Ottawa area for permission to operate the Rutter radar system in their vicinity. He was successful in obtaining permission from the authorities at the Gatineau Executive Airport (GEA) and Transport Canada to park the MRL truck, and operate the radar, at a site about 300m from the western end of the runway. The location of the site and the MRL truck are shown in Figure 16.

Figure 15: MRL truck “architecture”. The stabilizer shown in the diagram was necessary to minimize the swaying of the cargo box from swaying in windy conditions. Note: despite the location of its antenna, the ADS-B receiver was not adversely affected by its proximity to the radar transmitter.

18 DRDC Ottawa TM 2013-152

Figure 16: Various perspectives of the MRL truck and its location relative to the runway shown in the Google Earth picture in the lower right. The red lines show the directions toward the Shirley’s Bay Campus (upper) and the Ottawa International Airport (lower). (Photos by the author)

As shown earlier in Figure 13, the GEA had the added benefit of being only 23 km from the Ottawa International Airport (OIA), thus providing the radar system with the opportunity to track larger aircraft using that location. Since some of these larger aircraft would also carry ADS-B transceivers, they could provide useful ground-truth for the radar detection and tracking results.

The DRDC ADS-B receiver model used in the trials was an SBS-1 “Virtual Radar” receiver purchased from Kinetic Avionics in the UK. As shown in Figure 15, the DRDC ADS-B receiver antenna was mounted on top of the truck during the trials and attached to the receiver and data- logging computer inside the truck’s lab area. The RF emissions from the Rutter radar system in such close proximity to the ADS-B’s receiver had no apparent impact on the SBS-1’s operation. A picture of the ADS-B receiver system along with the data logging laptop and a typical display from the trials is shown in Figure 17.

DRDC Ottawa TM 2013-152 19

Figure 17: Kinetic SBS-1 ADS-B receiver and data logging system used to collect ground truth data during the trials at the GEA. The “Virtual Radar” display in the upper right corner shows some of the air traffic observed in the Ottawa area on 18 Sept. 2010 within a range of 209.5Nm. (Photos by the author)

The original plan was to execute the trials intermittently over a period of about a month, from late July to the end of August. However, when it was learned that an air-show was scheduled to take place on the weekend of 18 September, with aircraft arriving on the 17th and leaving on the 19th, these dates were folded into the test plan. This afforded an excellent opportunity to test the radar system against a wide range of aircraft types.

Table 3 provides a listing of the periods during which both Radar and ADS-B data were collected, as well as an indication of the primary mode(s) that the radar system operated in, whether it was Short, Medium, or Long range. As implied by the table, it was not always possible to collect overlapping radar and ADS-B data. Also, for some periods during the GAS, the radar was operated in Short or Medium range mode which, although useful for studying the tracking of aircraft in the immediate vicinity of the GEA, was not conducive to studying the long range tracking of larger commercial aircraft with corresponding ADS-B reports. Table 3: Radar and ADS-B data collected between 29 July and 18 Sept.

Date Radar Radar Radar Mode ADS-B Start ADS-B Stop Start (EDT) Stop (EDT) (S,M,L) (EDT) (EDT)

29 July 14:15:18 15:29:46 L (C) 12:42:29 15:29:53 15:30:16 L(C) 15:30:43 16:16:15 16:16:49 L 17:29:29 18:30:00 L(C)

20 DRDC Ottawa TM 2013-152

Date Radar Radar Radar Mode ADS-B Start ADS-B Stop Start (EDT) Stop (EDT) (S,M,L) (EDT) (EDT) 30 July 09:58:30 16:58:33 L (some M) 13:10:11 17:04:38 6 August 16:11:03 16:36:10 L 16:09:24 16:42:31 17:25:32 L 17:30:44 17:36:45 S 17:39:47

11 Aug. 12:42:19 15:43:08 L 13:43:56 15:47:13 17:48:39 L 17:52:44 19 Aug. 10:06:23 10:50:24 L 10:44:54 12:46:18 17 Sept. 14:12:49 15:04:17 L 15:18:04 17:56:02 L 17:30:24 18:47:41 18:47:55 19:38:37 18 Sept. 13:47:50 14:52:53 L 15:08:37 15:41:10 S,M,L 13:54:57 16:21:49 18:06:17 S,M,L 18:13:03 19:32:08 L 19:30:47

S=Short Range Mode (0-5.56 km (3 Nmi))/ M=Medium Range Mode (0-22.22 km (12 Nmi)) L=Long Range Mode (0-74 km (40 Nmi)) C=(Partly) Corrupted data file

One factor that must be appreciated when looking at any of the results obtained during these trials is that they were all collected during favourable weather conditions. This was necessary during the earlier part of the trials because the protective tarp, shown in Figure 16 covering the trap door opening for the radar antenna, had not been completed and installed until the weekend of the air- show. If trials had been conducted during precipitation, the interior lab area of the MRL’s cargo box would have been compromised and equipment could have been damaged.

For purposes of safety and security the radar antenna needed to be set up and taken down during each day of trials to allow the trap door on the roof to be closed while the radar was not in operation. This mitigated any risks associated with possible unauthorized access to the interior as well as preventing precipitation damage.

DRDC Ottawa TM 2013-152 21

4 Analysis and Results

4.1 Tracking of Small to Medium Sized Aircraft

Over the period of the air surveillance trials at the Gatineau Executive Airport from 30 July to 19 Sept. 2010 a significant number of small to medium sized aircraft were observed in the vicinity of the radar site. Unlike the commercial flights that were observed in the Ottawa-Gatineau area during the same trials period (which are discussed later in Section 4.2), these aircraft did not carry ADS-B transceivers; therefore, the only means of obtaining any ground-truth information on the aircraft types and flight paths was by using visual means, e.g. naked eye, binoculars, and digital hand-held camera recordings (still photographs and videos). Using such means it was often possible to read the wing numbers on the aircraft so that post-trials information about the aircraft could be obtained from relevant sites on the internet (e.g. manufacturers, airline companies, aircraft enthusiasts, or Wikipedia). A compendium of the pictures (still photographs and screen captures from video clips) taken over the course of the trials is provided in Annex C along with a table giving a brief physical description of the aircraft, and the time that each particular photo was obtained. Annex D contains a table providing more detailed specifications—if they were available—for the various aircraft seen during the trials, as well as specifications for some of the aircraft expected to be seen in the Arctic. The pictures and video clip files beginning with the prefix “100_” were taken by the author, whereas those with the prefix IMG_, DSCF or MVI_, were collected by Mr. G. Duff.

As per the manufacturer’s recommendations, the integration window, i.e. the number of pulses integrated over each 1° azimuth scan radial (corresponding to the antenna’s nominal 3dB beamwidth of 1°), for each of the three operational modes, was 10, 7 and 3 pulses for Short, Medium and Long respectively. The integration window is set to a value that should not be greater than nearest integer value calculated according to equation (7), which is based on the radar system’s beamwidth, the pulse repetition frequency (PRF) and the rotation rate.

Window  (pulses/second)  (seconds/scan)  (degrees/s can)-1  beamwidth

 3000 (Short) 60 beamwidth   PRF   beamwidth; ,1 PRF  1800 (Medium) (7) 45 rpm 360  785 (Long) 11 7(Short), (Long)3(Medium),

Note that although value for the integration window in Short Range was calculated to be 11, the default value for the window set by the radar provider was 10, so the latter value was retained.

The analysis and results of tracking these smaller aircraft will be divided up into two periods, before and during the Gatineau Air Show as described in Section 4.1.1 and Section 4.1.2 respectively.

22 DRDC Ottawa TM 2013-152

4.1.1 Small Aircraft Detection and Tracking on 30 July, and 6-11 Aug.

Most of the aircraft observed in the immediate vicinity of the GEA, during the stated time period, were usually the size of a DHC-6 Twin Otter, or smaller. In one instance, on 30 July at 12:24 pm, a Beaver float plane was photographed taking off from the GEA. This would have been an excellent stand-in for a DHC-6 Twin Otter; however, while it was being tracked by radar, it did not maintain a flight path that could effectively exercise the radar. Specifically, after taking off from the west end of the runway, it slowly veered northwest but disappeared from the radar display after about 5.6 km because its low altitude led to it being masked by the local terrain and vegetation. A picture of the Beaver, and its associated radar track are shown in Figure 18

Figure 18: Beaver float plane (upper photo, with inset) and the corresponding radar track (bottom two images). The track in the radar display is a mosaic generated from multiple overlapping radar images (radar system operating in long range mode).

There were also a number of helicopters observed using this airport, including a Bell 206A JetRanger that was seen a number of times (see Annex C). Unfortunately, as shown in Figure 19, the Bell 206A only appeared to be doing small circuits of the airport, at least during those times when it could be positively identified. The maximum range from the radar, in the example shown, was only 4.2 km. These may have simply been student training runs. Therefore, this aircraft didn’t seriously challenge the radar systems capability.

DRDC Ottawa TM 2013-152 23

The pale yellow lines that can be seen in Figure 19 (and in other radar images throughout this report), define polygonal areas where radar detections due to significant land clutter (persistent white areas) are excluded from the radar’s plot extractor and tracker. These areas are “land- masked” to prevent the land-clutter echoes from saturating the radar’s plot extractor and tracker.

Figure 19: Track (lower images) of the Bell 206 helicopter shown in the upper photograph (with inset). The track in the radar display is a mosaic generated from multiple overlapping radar images (radar system operating in long range mode).

Figure 20 shows the radar track of a Diamond DA-20-A1 Katana as it approached the GEA for a landing on the afternoon of 11 Aug. 2010. The photograph at the top left is consistent with the aircraft making a slight turn westward just before turning eastward to line up with the runway. In this case the aircraft was detected at a maximum range of 20 km.

24 DRDC Ottawa TM 2013-152

Figure 20: A Diamond DA-20-A1 Katana (based on wing ID, C-FWSH, in upper photo) and the corresponding radar track (bottom images). The track in the radar display is a mosaic generated from multiple overlapping radar images (radar system operating in long range mode).

In addition to the small aircraft observed using the GEA, there were also many small aircraft observed (via radar) using the Rockcliffe Airport. This is a relatively small uncontrolled airport (single active runway of about 1km in length), which is located roughly 8km southwest of the GEA, and is operated by the Rockcliffe Flying Club. This runway is primarily for the use of small aircraft with wingspans less than 12 m. One example of a track recorded for an aircraft landing at this airport on 6 Aug. 2010 is shown in Figure 21.

DRDC Ottawa TM 2013-152 25

Figure 21: Radar track (red ellipses) of a small aircraft (type unknown) landing at the Rockcliffe Airport on 6 Aug. 2010 at approximately 5 pm EDT. The maximum range where the aircraft was first detected was approximately 27km using the radar system’s long range mode.

26 DRDC Ottawa TM 2013-152

4.1.2 Gatineau Air Show 17-19 Sept. 2010 During the period of 17 to 19 September 2010, “Vintage Wings of Canada” hosted two concurrent events (described online at [15] and [16]) at the GEA, i.e. “Wings Over Gatineau” and “Oskosh North”. These will later be collectively referred to as the “Gatineau Air Show” or GAS. “Wings Over Gatineau” was a one day event held on the 18-Sept. to commemorate Canada’s Victoria Cross recipients from World War I and World War II. The second three day event, referred to as “Oshkosh North”, held from 17-19 September, was to host the first Canadian Experimental Aircraft Association (EAA) convention and fly-in. Over the course of the three days there was a wide variety of fixed wing aircraft types that were landing, taking off and flying circuits around the airport. The sizes of the aircraft ranged from those as small as Cessna 150 to as large as a Lancaster Mark X bomber and a PBY-5A Canso (Flying Boat). There were both high-wing and low-wing types, and although most were propeller driven, there were also two high speed jets: a T-33 Turbo (Shooting Star) and an F86-E Sabre 5. A list and description of the aircraft types that were observed over this period (as well as the rest of the trials period) is provided in Annex C. It is beyond the scope of this report to provide an exhaustive examination of the Rutter 100S6 radar system’s ability to detect and track all of the aircraft seen; however the report will provide a small representative sample of results from the spectrum of sizes and types.

During the period of the GAS, the Rutter 100S6 radar system was operated in all three range modes (Short, Medium and Long, but not simultaneously) in order to determine its relative effectiveness in each mode.

Figures 22 to 31 show some of the typical aircraft that were observed, along with some of the radar system’s detection and tracking results.

Figure 22 shows a small low-winged aircraft that was tracked to a range of just over 13.8km with the radar set to Long Range mode. Unfortunately, it was not possible to get the wing numbers of the aircraft to identify it and thus determine its dimensions.

One of the three largest propeller driven aircraft seen at the GAS was a Beech TC-45G Expeditor twin engine aircraft named the GTMO BAY-086, which is shown in Figure 23. Figure 24 shows some screen captures of the radar results as the aircraft was being tracked in Long Range mode, from take-off until the track was lost at a range of 21.6 km. For the track sequence shown, the aircraft‘s aspect with respect to the radar antenna was tail-on and receding.

Figure 25 shows some photographs of another small, single-engine, low-winged aircraft that was identified after the trials as a Mooney 20E aircraft, based on observing its wing numbers during take-off. Although the initial direction was westward (as indicated by the photos from the MRL looking eastward), it quickly made a clockwise turn and headed east. As shown in Figure 26, the aircraft highlighted by the ellipse was tracked using Long Range mode until it disappeared shortly after reaching a range of 17.1 km.

Figure 27 shows several photographs of the PBY-5A Canso flying boat, one of the two largest propeller aircraft (next to the Lancaster) at the GAS. Figure 28 shows some of the screen captures from the radar display as the aircraft was tracked, in Long Range mode, until the track was lost at a range of 30.3 km. This series of screen captures also compares the display with the track identification activated and deactivated to make it easier to see the strength of the radar echo.

DRDC Ottawa TM 2013-152 27

winged winged aircraft tracked to a range of just over 13.8km with the radar in Long -

: Small low 22 mode. Figure Figure Range

28 DRDC Ottawa TM 2013-152

Figure 23: Three photographs of the Beech twin engine aircraft at the air show plus a similar aircraft (lower right) in flight. The two in the upper row were taken by the author at the air show (just prior to the radar sequence in Figure 24) and the lower left is courtesy of Adam Mooz (www.flickr.com/photos/adammooz/5038812759).

Figures 29 to 31 show the photographs and radar tracking results for the Lancaster Mark X as it flew in formation around the airport with a fighter escort of between one and four World War II fighter aircraft (including a Corsair and a Spitfire). The radar results compare the ability of the radar to resolve the multiple aircraft in each of the three radar range modes (Short, Medium and Long). Unfortunately the formation never flew out to ranges beyond a few km from the radar system, so its ability to detect and track the formation was never seriously challenged. Also, although not shown in any of these sequences, it was obvious during the trials that (unlike slow moving marine targets) scan averaging could not be used to enhance the detection of aircraft. This was because no portions of the aircraft target echoes would overlap between successive scans. Therefore, if scan averaging had been used it would have created N-1 “ghost” images of each fully resolved target where N is the number of scans averaged.

DRDC Ottawa TM 2013-152 29

30 DRDC Ottawa TM 2013-152

Figure 25: Small single- engine low-winged Mooney 20E aircraft during take-off; photographed by the author. Although the initial direction was westward, it quickly made a clockwise turn and headed east.

DRDC Ottawa TM 2013-152 31

Figure 26: Screen captures of the radar display while tracking the Mooney 20E in Long Range mode. The most western arrow (N is 0°) in the image at 17:45:20 points to the aircraft echo before the tracker has locked on. The remaining three images show the aircraft track (#113) until it was lost just after reaching a range of 17.1 km.

32 DRDC Ottawa TM 2013-152

Figure 27: Several views of the PBY-5A Canso. The two photos in the upper row and at the bottom were taken by the author at the GAS, whereas the central image is from a book on World War II aircraft by B. Gunston [17]. The bottom photo also shows the Lancaster taking off behind the Canso.

DRDC Ottawa TM 2013-152 33

show and and show - yed, whereas whereas yed, it left the air the leftit

o allow the radar echo to be seen. For the the For be seen. to echo radar the allow o on and receding. on and - 5A Canso in Long Range mode as mode in Long Range 5A Canso - : Series of screen captures of the radar display while tracking the PBY the tracking while display radar the of captures screen of Series : 28

Figure Figure displa markers track the with the display row show upper 30.3 km. The over just at range detection of out until flew westward t suppressed the markers with same time the approximately at display the row shows the bottom tail was antenna radar to the respect with aspect the aircraft‘s here, shown sequence track

34 DRDC Ottawa TM 2013-152

Figure 29: Pictures of the Lancaster Mark X flying in formation with a Corsair during the WOG air show. The quality of the upper photo is somewhat degraded due to magnification and cropping of the original picture.

DRDC Ottawa TM 2013-152 35

Figure 30: Screen captures of the radar display in Short Range mode while tracking the Lancaster and Corsair flying in formation doing a circuit around the airport. The third image (lower left) shows two new aircraft joining the formation (note: track markers are turned off in some of the images).

36 DRDC Ottawa TM 2013-152

Figure 31: Screen captures of the radar display comparing the resolution in all three modes: Short, Medium and Long. In Short range mode all five aircraft (Lancaster plus four fighter escorts) in formation can just be resolved, but in Long range mode all five aircraft merge into a single “blob”.

DRDC Ottawa TM 2013-152 37

4.2 Commercial Flights 29 July to 18 Sept. 2010

Over the trials period of 29 July to 18 Sept. 2010 a large number of commercial passenger and cargo flights were observed in the Ottawa-Gatineau area. This was accomplished by using a combination of ADS-B reports, radar detection and tracking, or by visual means. The large number of sightings is not surprising given that the Ottawa-Gatineau area is part of a major air corridor linking cities along the Canada-US border. While many of the flights were associated with destinations in Toronto and Montreal, there were still quite a few landing at, or flying out of, the Ottawa International Airport. Also, while a large number of such flights provided ADS-B reports, a significant percentage did not. Most of the aircraft that didn’t broadcast ADS-B reports were often observed visually to be smaller passenger aircraft, such as turboprops like the DASH- 8, or short-haul jets like the ATR42; these are often associated with domestic flights of less than 3hrs duration.

In the analysis which follows, the main focus is devoted to commercial flights that provided ADS-B reports because they provided ground truth information for the radar tracking results that will be shown in Section 4.2.2.

This section is divided into two major subsections. The first subsection, 4.2.1, will only focus on describing the flight paths of aircraft reported via ADS-B, whereas the second subsection, 4.2.2, focuses on the radar detection and tracking results that could be associated with ADS-B tracks. To reflect this separation the results in this section are provided mainly in terms of two visual formats to provide the reader with a reasonable perspective of the following:

1) A three dimensional view of the aircraft flight path (as reported by the ADS-B system) in relation to the main beam of the radar antenna at the GEA site, and the location of the landing strip at Ottawa International Airport.

2) The aircraft flight path from an overhead, or “plan” view —such as that provided by a radar PPI display—so that it could be compared to the two dimensional radar track, and the range relative to the GEA radar site.

It should be noted that the ADS-B data from 29 July in subsection 4.2.1.1 was only included for completeness since most of the radar data collected during that day was corrupted and comparisons between the two sets of tracks could not be made.

4.2.1 Three Dimensional Views of Flight Paths Based on ADS-B Reports.

The intension of this subsection is to show the typical types of aircraft that fly through the Ottawa-Gatineau AOI employing ADS-B systems, as well as their typical flight paths. The totality of the information provided will show the plausibility and the potential utility of the 100S6 system to provide limited surveillance of these aircraft. In most cases only the tracks from aircraft within a radius of about 60km of the GEA are shown because those that are farther away would have virtually no chance of being detected or tracked by the 100S6 radar system.

38 DRDC Ottawa TM 2013-152

The sets of figures that follow in this subsection provide three dimensional perspectives of the commercial aircraft flight paths with respect to the radar site at the GEA, and with respect to the radar antennas 3 dB elevation beamwidth. These plots were generated by converting the flight path information from ADS-B reports into Keyhole Markup Language (KML) files so that they could be displayed in Google Earth (or any similar Geographic Information System (GIS)). They are meant to provide the reader with a visual aid to see when the flight paths tend to be outside the anticipated detection envelope of the radar system. The maximum vertical extent of the radar system’s main beam is represented by the segmented yellow cone centred on the radar system site. The assumed maximum radar detection range of 45 km is indicated by the edge of the cone. In some figures the edge of the cone is extended to the ground so that the relative altitude of aircraft can be seen as they enter or leave the area of interest at that range.

Each set of figures, for each day of trials, starts with an overhead “plan” view showing all of the ADS-B tracks of interest, with each of the tracks labelled according to the aircraft’s ICAO24 ID and Callsign. When feasible, each ADS-B track has a unique colour and/or marker style to help identify it in the subsequent 3D images when labelling each track often becomes too difficult or confusing to label.

4.2.1.1 29 July 2010

In Figure 32 two dimensional plan views of the ADS-B tracks collected during 29 July. 2010 are provided. Only tracks from the four aircraft with a potential to be detected by the radar system are shown in colour, whereas all others are shaded white. The four potential radar candidates are labelled with the ICAO24 identity (i.e. the first six characters) and Callsign (the remaining characters after the underscore) of each aircraft.

In Figure 33 the ADS-B tracks displayed in Figure 32 are provided again, but from three different three dimensional perspectives in relation to the expected radar detection envelope (yellow cone).

DRDC Ottawa TM 2013-152 39

Figure 32: Two dimensional plan view of the ADS-B tracks for 29 July 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential to be detected by the radar system are shown in colour, the others are in white.

40 DRDC Ottawa TM 2013-152

Figure 33: Three dimensional views of the 29July ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 45 km range “limit” indicated by the yellow cone and cylinder respectively.

4.2.1.2 30 July 2010

In Figure 34 two dimensional plan views of the ADS-B tracks collected during 30 July 2010 are displayed. Four tracks from four separate aircraft were observed to have a potential to be detected by the radar system, whereas one was outside the expected radar detection range and is shaded white. All of the five ADS-B tracks are labelled with the ICAO24 identity and Callsign of the corresponding aircraft. The scale of the images decrease from top to bottom; the topmost image gives the broadest overview of the area and the bottom one provides the most surface detail near the OIA. It can be seen from the figure that one ADS-B track shaded blue and labelled C061E9_ACA839 (Air Canada Boeing 767-375 (ER), Flight 839) is misreporting its position by 900 m to the West.

In Figure 35 the ADS-B tracks displayed in Figure 34 are provided again, but from two different 3D perspectives in relation to the expected radar detection envelope (yellow cone).

DRDC Ottawa TM 2013-152 41

Figure 34: Two dimensional plan views of the ADS-B tracks for 30 July 2010 showing the (ICAO24) identity and Callsign of each aircraft. Only one track was not expected to be detected by the radar, and it is shaded white in the upper image. Notice the 900 m offset for the blue track.

42 DRDC Ottawa TM 2013-152

Figure 35: Three dimensional views of the 30 July ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 45 km range “limit” indicated by the yellow cone and cylinder respectively.

DRDC Ottawa TM 2013-152 43

4.2.1.3 6 August 2010

In Figure 36 two dimensional plan views of the ADS-B tracks collected during 6 Aug. 2010 are displayed. Only the track from one aircraft with a potential to be detected by the radar system is shown in colour (i.e. red), whereas the four others are shaded white. All of the five ADS-B tracks are labelled with the ICAO24 identity and Callsign of the corresponding aircraft.

In Figure 37 the ADS-B tracks displayed in Figure 36 are provided again, but from two different 3D perspectives in relation to the expected radar detection envelope (yellow cone).

Figure 36: Two dimensional plan view of the ADS-B tracks for 6 August 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential to be detected by the radar system are shown in colour, the others are in white.

44 DRDC Ottawa TM 2013-152

Figure 37: Two 3Dl views of the 6 August ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 45 km range “limit” indicated by the yellow cone and cylinder respectively.

4.2.1.4 11 August 2010

Figure 38 and Figure 39 show two important examples of the apparent occasional fallibility of ADS-B, a system which is intended as an anti-collision system for aircraft. The first figure shows the incorrectly reported track (denoted by the red triangles) of a Korean Airlines Boeing 777- 2B5ER, flight KAL09, on 11 Aug. 2010 from 14:18:35 EDT to 14:36:42 EDT as it flew somewhere within the vicinity of the Ottawa-Gatineau AOI. It is not possible to know exactly where its true flight path was because, although the latitude looked reasonable, the reported longitude appeared to be random. As shown in the lower half of Figure 38, if a path is drawn between each consecutive time stamped location, the lines criss-cross the Northern Hemisphere above approximately 43°N.

DRDC Ottawa TM 2013-152 45

Figure 39 shows plan views from three different GE map images of ADS-B tracks from at least six different aircraft observed in the Ottawa-Gatineau area on 11 August 2010. The scale of the images decrease from top to bottom; the topmost image gives the broadest overview of the area and the bottom one provides the most surface detail near the OIA. This is an important example because it again shows that the ADS-B reports are not infallible. The light blue track marked C04EB6_ACA829 should be following, and virtually overlapping, the same route as the green track marked C051E2_ACA889 but is incorrectly reporting its location as about 12km west and 1 km south of its true course. A similar but less extreme track offset error can be seen by close examination of track C04EB6_ACA838 in the bottom image of Figure 39. In this case the flight path of the aircraft is misreported by their ADS-B system as being roughly 1 km south of the airport.

The silver track in the bottom image, marked by ADECAB_499AG, is just an international flight that does not land in Ottawa but is probably one flight-leg that links Toronto and Montreal.

Figures 39 to 41 show 3D plots of the same tracks provided in Figure 39 but seen from different perspectives. For comparison, in some cases the maximum range “curtain” is turned on while in others it is switched off. These plots make it easier to see that an aircraft may be within range of the radar system, but not within its main beam.

46 DRDC Ottawa TM 2013-152

Figure 38: The incorrectly reported track of a Korean Airlines (Republic of Korea) Boeing 777- 2B5ER, flight KAL09, on 11 Aug. 2010 from 14:18:35 EDT to 14:36:42 EDT.

DRDC Ottawa TM 2013-152 47

Figure 39: Two dimensional plan view of the ADS-B tracks for 11 Aug. 2010 showing the (ICAO24) identity and Callsign of each aircraft. Only tracks from aircraft with the potential of being detected by the radar system are shown. Notice the significant error offset for the C01766_564 track (light blue, left of centre) compared to the C051E2_ACA889 (green) track.

48 DRDC Ottawa TM 2013-152

mitted mitted

B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to to fromin the B the OIA. vicinity of relative tracks tracks are The aircraft shown - sional views sional of the views Aug. 11 ADS Three dimen Three : views to allow the tracks to be seen under the radar cone. radar the under seen to be tracks the allow to views 40

Figure Figure the nominal maximum edge of the radar antenna’s main elevation beam indicated by the yellow cone. The 40km range “limit” is o in these

DRDC Ottawa TM 2013-152 49

indicated indicated by the yellow

limit” B tracks from aircraft in the vicinity of the OIA. The tracks are shown -

nominal nominal maximum edge of the radar antenna’s main elevation beam and 40km range “ : Three dimensional views of the 11 Aug. ADS 41

Figure relative to the respectively. cylinder cone and

50 DRDC Ottawa TM 2013-152

indicated indicated by the yellow cone

limit” aft aft in the vicinity of the OIA. The tracks are shown B B tracks from aircr -

: : Additional three dimensional views of the 11 Aug. ADS 42

Figure Figure relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “ respectively. and cylinder

DRDC Ottawa TM 2013-152 51

4.2.1.5 30 July 2010

4.2.1.6 17 Sept. 2010

Figure 43 shows a plan view of ADS-B tracks from at least six different aircraft observed in the Ottawa-Gatineau area during 17 September 2010. The flight associated with the dark blue track labelled as C03472_225 was a flight that first landed at, and then later flew out of, the OIA. As in the previous example from 11 August, there was also one over-flight of the airport that was recorded and shown by silver track.

Figures 44 to 49 show 3D plots of the same tracks shown in Figure 43 but seen from different perspectives, with the maximum range “curtain” either on or off. In some cases, such as Figures 46 to 49, the yellow radar coverage cone was removed to allow unobstructed views of the three dimensional ADS-B tracks. This makes it very easy to see that the silver track was just an over- flight and did not land at OIA. Figures 48 and 49show how well the ADS-B tracks (usually) align with the various runways when the aircraft where landing or taking off.

Figure 43: Two dimensional plan view of the ADS-B tracks for 17 Sept. 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential of being detected by the radar system are shown.

52 DRDC Ottawa TM 2013-152

Figure 44: Three dimensional views of the 17 Sept. ADS-B tracks from aircraft in the vicinity of the OIA. The tracks are shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “limit” indicated by the yellow cone and cylinder respectively. The 40km range “limit” is omitted in these views to allow the tracks to be seen under the radar cone. The look direction is provided by the compass in the upper right corner of each image.

DRDC Ottawa TM 2013-152 53

The The tracks are shown rovided by the compass compass by the rovided The look direction is p direction The look

B tracks from aircraft in the vicinity of the OIA. -

: Three dimensional views of the 17 Sept. ADS 45

Figure relative to the nominal maximum edge of the radar antenna’s main elevation beam indicated by the yellow cone. The 40km range cone. the radar be seen under to tracks the allow to views in these omitted “limit” is image. each of right corner upper in the

54 DRDC Ottawa TM 2013-152

Figure 46: Three dimensional perspective of the ADS-B tracks from aircraft in the vicinity of Ottawa International Airport and the Gatineau Executive Airport on 17 Sept. 2010. This view is looking toward the Northwest. The “silver” track is actually bypassing the OIA.

Figure 47: Three dimensional perspective of the ADS-B tracks from aircraft in the vicinity of Ottawa International Airport and the Gatineau Executive Airport on 17 Sept. 2010. This view is looking toward the West.

DRDC Ottawa TM 2013-152 55

Figure 48: Three dimensional view overlooking the Ottawa International Airport from the perspective of aircraft approaching a landing from the Southwest. ADS-B reports from all of the aircraft except one (green) are aligned with their respective runways.

Figure 49: Three dimensional view overlooking the Ottawa International Airport from the perspective of an aircraft approaching a landing from the Southeast on 17 Sept. 2010.

56 DRDC Ottawa TM 2013-152

4.2.1.7 18 Sept. 2010

Figure 50 shows two plan views of tracks generated by ADS-B reports from at least twelve different aircraft in the Ottawa-Gatineau area during 18 September 2010.

Figures 51 to 53 show 3D plots of the same tracks shown in Figure 50 but as seen from different perspectives with the maximum range “curtain” either on or off. These plots make it easier to see that an aircraft may be within range of the radar system, but not within its main beam.

Figure 50: Two dimensional plan views of the ADS-B tracks for 18 Sept. 2010 showing the identity and Callsign of each aircraft. Only tracks from aircraft with the potential of being detected by the radar system are shown. The lower image is an expanded view of the area centred on the OIA.

DRDC Ottawa TM 2013-152 57

limit” 40km range “limit” is omitted in these views to allow the

B tracks from in aircraft the vicinity of the OIA. The tracks are - The The look direction is provided by the compass in the upper right corner of each

s s of the 18 Sept. ADS : Three view dimensional 51

Figure shown relative to the nominal maximum edge of the indicated radar by the antenna’s yellow cone main and cylinder elevation respectively. The beam and 40km range “ tracks to be seen under the radar cone. image

58 DRDC Ottawa TM 2013-152

indicated indicated by the

limit” B tracks from aircraft in the vicinity of the OIA. The tracks are - ws ws of the 18 Sept. ADS

: Additional three dimensional vie 52

Figure shown relative to the nominal maximum edge of the radar antenna’s main elevation beam and 40km range “ respectively. cylinder and cone yellow

DRDC Ottawa TM 2013-152 59

llow llow cone. The 40km range

B tracks from aircraft in the vicinity of the OIA. The tracks are shown - : Three dimensional views of the 18 Sept. ADS 53 Figure relative to the nominal maximum edge of the radar antenna’s main elevation beam cone. radar the under be seen to tracks indicated the to allow views in these is omitted “limit” by the ye

60 DRDC Ottawa TM 2013-152

4.2.2 Two Dimensional Plan Views Comparing the Radar Tracks and ADS-B Reported Flight Paths

This subsection provides results comparing the radar detections and tracks collected by the Rutter 100S6 radar system with their corresponding ADS-B tracks. The sets of figures provide two dimensional, plan views of the commercial aircraft flight paths overlaid with the radar detection and tracking results. In all cases the only radar mode that was being used was the long range mode.

The analysis of the radar data for this report was not intended to be exhaustive, but to provide some indication of the radar system’s capability to detect and track medium to large sized commercial cargo or passenger aircraft. Therefore not all results are shown for every day that radar data was collected.

Aside from misreported ADS-B tracks noted in Subsection 4.2.1, some of the discrepancies between the radar and corresponding ADS-B tracks may be accounted for by the fact that the radar data was not corrected in order to account for the relative differences in altitude between the aircraft and the radar antenna. Typical aircraft altitudes at a range of 40 km were between 3 km and 9 km, which as shown in Figure 54 would introduce offsets of between 100 m and 1 km respectively. The parameters shown in Figure 54 are defined as:

re=Earth’s radius

ha=Antenna height (m)

ht=Target height (m)

Rt=Slant range to target measured by the radar system

R0=actual surface range of the aircraft based on reported latitude and longitude

Rts=overestimated surface range based on the radar measurement without corrections

Figure 54: Some offsets may occur between the ADS-B reported range and the Radar range when plotting the results on a map if all of the geometry is not accounted for. The latitude and longitude of the aircraft is projected to the surface directly beneath it, whereas the location based on the radar range and azimuth approximates R0 by using Rt.

DRDC Ottawa TM 2013-152 61

There may also have been a slight offset in the antenna azimuth pointing direction that was not fully corrected.

The data points which generate each complete radar track generally consist of a combination of track segments that were:

a. Automatically acquired;

b. Manually initiated; and/or

c. Visually observed detections that were recorded manually.

The latter were occasionally required for long range contacts, or when an aircraft executed a manoeuvre that exceeded the trackers ability to keep locked on because of the slow update rate of the radar scanner, the high speeds of the aircraft, and radar echo fades. For some of the flights that caused problems with the tracker, the aircraft was flying at speeds of between 400 and 600 kph while executing a 90° to 180° turn within a turning diameter of less than 10 km. For the long range targets visual tracking was often required for two reasons:

1) The contact was at a long range (e.g. 40-50 km) so only relatively few detections were made by the radar system, while the target was at broadside, before the target was lost; and 2) Because it was often difficult to optimize the radar’s alpha-beta M-of-N tracker to maintain a track when the number of detections (M) for a specific number of scans (N) had too great a variability. The accepted setting for a marine navigation radar system with Advanced Radar Plotting Aids (ARPA) is that the tracker should maintain a track when there are as few as 5detections out of 10 scans but for a track to be confirmed the radar must first make at least 5 detections. It should also be noted that there may be slight time differences of several seconds between a radar track data point and its corresponding ADS-B report. This is mostly due to slight offsets in the time base between the two recording systems.

4.2.2.1 29 July 2010 There were no useable radar tracks from this day because most of the data files (except for one very short one) were corrupted to a degree that they weren’t deemed worth analysing. Figure 55 provides an indication of the severity of the problem.

62 DRDC Ottawa TM 2013-152

4.2.2.2 4 August 2010

4.2.2.3 30 July 2010

The following set of figures (Figures 56 to 58) compare the ADS-B tracks for a number of commercial passenger flights with radar detections and tracks for the corresponding aircraft on the 30 July 2010.

In two out of the three examples the radar and ADS-B results align quite well, but in the first figure (Figure 56) it can be seen that there was a slight offset of 900 m in the ADS-B reported position because it does not line up with the runway, whereas the radar track does.

DRDC Ottawa TM 2013-152 63

Figure 56: ADS-B (blue) and radar tracks (red) for an Air Canada Boeing 767-375 observed landing at Ottawa International Airport on 30 July. 2010. The radar tracked it between 16:23:39 EDT and 16:29:04 EDT to a maximum range of about 27.2 km.

64 DRDC Ottawa TM 2013-152

Figure 57: ADS-B (yellow) and radar tracks (red) for an Air Canada Airbus A330-343X observed landing at Ottawa International Airport on 30 July. 2010. The radar tracked it between 15:28:47 EDT and 15:35:55 EDT to a maximum range of about 38.7 km.

DRDC Ottawa TM 2013-152 65

Figure 58: ADS-B (light blue) and radar tracks (red) for an WestJet Boeing 737-7CT/W observed taking off from Ottawa International Airport on 30 July. 2010. The radar tracked it between 14:53:16 EDT and 14:56:32 EDT to a maximum range of about 23.8 km.

66 DRDC Ottawa TM 2013-152

4.2.2.4 6 August 2010

Figure 59 shows a plan view of ADS-B tracks for a number of commercial passenger flights on 6 August 2010 within potential radar detection range. However, as seen in the lower half of the figure only one radar track was observed to match the ADS-B track from a WestJet Boeing-737- 6CT. This can be accounted for by the other flight paths being outside the detection envelope of the radar antenna’s main beam.

Figure 59: ADS-B (blue) and radar tracks (white) for a WestJet Boeing-737-6CT observed landing at Ottawa International Airport on 6 Aug. 2010. The radar tracked it between 16:44:06 and 16:50:07 to a maximum range of about 44.7 km. The other tracks are of ADS-B reports from aircraft that weren’t detected by radar.

DRDC Ottawa TM 2013-152 67

4.2.2.5 11 August 2010

The following set of figures (Figures 60 to 64) compare ADS-B tracks for a number of commercial flights with radar detections and tracks for the corresponding aircraft on the 11 Aug.

In Figure 60 the radar and ADS-B tracks are not aligned because there is a significant offset error in the ADS-B track of 12 km to the East and 1 km to the South, whereas the radar track does line up with the runway, as indicated by the green arrow.

In Figure 64 the radar and ADS-B tracks are not aligned because of an offset error in the ADS-B track of 1 km, whereas the radar track does line up with the runway.

Figure 60: ADS-B (red) and radar tracks (light blue) for an Air Canada Boeing-767-38E (ER) observed landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 15:27:33 and 15:34:20 to a maximum range of about 39.0 km. In this case the ADS-B track had offset errors of 12 km to the East and 1 km to the South. The green arrow shows the direction to, and orientation of, the runway.

68 DRDC Ottawa TM 2013-152

Figure 61: ADS-B (red) and radar tracks (light blue) for an Air Canada Airbus A330-343 observed landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 15:18:24 and 15:29:34 from a maximum range of about 40.1 km.

DRDC Ottawa TM 2013-152 69

Figure 62: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 17:39:22 and 17:45:27 from a maximum range of about 40.2 km.

70 DRDC Ottawa TM 2013-152

Figure 63: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-6CT observed landing at Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 16:45:33 and 16:48:35 from a maximum range of about 39.3 km.

DRDC Ottawa TM 2013-152 71

Figure 64: ADS-B (red) and radar tracks (light blue) for an Air Canada Boeing-767-38E (ER) observed taking off from Ottawa International Airport on 11 Aug. 2010. The radar tracked it between 17:26:39 and 17:32260 to a maximum range of about 39 km.

72 DRDC Ottawa TM 2013-152

4.2.3 17 September 2010

In the following two figures showing the tracking results for 17 September, Figure 65 compare s ADS-B tracks for a number of commercial flights with radar detections and tracks for the corresponding aircraft whereas Figure 66 shows a number of radar tracks from aircraft that were not broadcasting with ADS-B. The maximum detection range for any of the aircraft on this day was 48.9 km.

Figure 65: ADS-B and radar tracks for an Air Canada Boeing-767-375(ER) (ID: C0054A) and a WestJet Boeing 737-7CT (ID: C0669E) on 17 Sept. 2010. The AC and WJ flights were tracked to a maximum range of 29.5 and 28 km respectively.

DRDC Ottawa TM 2013-152 73

Figure 66: Additional radar tracks detected but not associated with any ADS-B reports recorded on 17 Sept. 2010. The maximum detected range of any of the aircraft was 48.9 km but since there was not an associated ADS-B track there was no altitude or identification information.

4.2.4 18 September 2010

The following set of figures (Figures 67 to 78) compare the ADS-B tracks for a number of commercial air flights with radar detections and tracks for the corresponding aircraft on 18 Sept. 2010. A number of miscellaneous radar tracks, not associated with ADS-B tracks (so ID and altitude were unknown), are plotted in Figure 79. The maximum range of any detected aircraft was 42.1 km. These tracks were probably generated by aircraft with short-haul flights that did not require them to carry ADS-B transceivers.

In Figure 70 the small circle to the right of the lower image identifies where and when the Rutter 100S6 alpha-beta tracker had difficulty maintaining a lock on a high speed target making a rapid

74 DRDC Ottawa TM 2013-152

manoeuvre. This is evidenced by a number of short straight track segments indicative of where, the rapid course deviation from the predicted track combined with the slow update rate to exceed the alpha-beta trackers abilities. This occurred several times during the manoeuvre resulting in the need to initiate several new tracks until the course straightened out. However, the data points for the radar track are plotted and identified here as a single track to avoid unnecessary confusion.

Figure 74 appears to be a good example of the radar system’s inability to detect and track an aircraft while it is otherwise within range but the geometry puts it too far outside the elevation beamwidth. In this figure an Air Canada Boeing-767-35H (ER) was observed on 18 Sept. 2010 taking off from Ottawa International Airport on a nearly radial course with the radar site, such that it flew almost directly overhead. Except for a brief gap of about one minute, from 17:37:44 to 17:38:51, the radar tracked the aircraft for about six minutes, between 17:34:47 and 17:40:40, to a maximum range of about 35.7 km. The coverage gap is probably due to the aircraft being outside the radar’s main beam, although the influence of nearby ground clutter (Figure 76) may also have played a role. By comparing Figure 74 with the Google Earth perspective views in Figure 75 it is obvious that the radar performed much better than anticipated, probably due to the aircraft’s larger RCS and close proximity. The results in Figure 74 indicate that when the aircraft was practically nose-on to the radar at a range of about 4 km it didn’t disappear from the radar until it was at an elevation of about 36° (i.e. 8400 ft altitude) and it reappeared when it was receding, tail-on, at an elevation of about 17° (i.e. 11700 ft altitude) and a range of 12.1 km. This is consistent with the expectation that the nose-on RCS could be up to 15dBsm greater than the tail- on RCS (refer back to Figure 6); however it also implies that the aircraft was probably being detected by the first sidelobe of the elevation beam pattern (refer back to Figure 2).

DRDC Ottawa TM 2013-152 75

Figure 67: ADS-B (red) and radar tracks (light blue) for an extended range (ER) Boeing-767- 35H from Ireland (Centennial Aviation) tracked by radar for a brief period between 13:55:21 and 13:56:10 at a range of about 40 km on 18 Sept. 2010.

76 DRDC Ottawa TM 2013-152

Figure 68: ADS-B (red) and radar tracks (light blue) for a United Airlines extended range (ER) Boeing-767-322 tracked by radar for a brief period between 14:27:12 and 14:27:50 at a range of about 47 km on 18 Sept. 2010.

DRDC Ottawa TM 2013-152 77

Figure 69: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport between 18:53:17 and 18:56:34 on 18 Sept. 2010. The maximum observed radar range was just over 39 km.

78 DRDC Ottawa TM 2013-152

Figure 70: ADS-B (dark blue) and radar tracks (red) for a WestJet Boeing-737-7CT/W observed landing at Ottawa International Airport between 17:29:43 and 17:38:37 on 18 Sept. 2010. The maximum observed radar range was 26.3 km. The small circle in the lower image identifies where and when the Rutter 100S6 alpha-beta tracker had difficulty maintaining a lock on a high speed target making a rapid manoeuvre.

DRDC Ottawa TM 2013-152 79

Figure 71: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 17:04:02 and 17:07:44 and to a maximum range of about 42.8 km.

80 DRDC Ottawa TM 2013-152

Figure 72: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 14:17:47 and 14:19:47 and to a maximum range of about 30.9 km.

DRDC Ottawa TM 2013-152 81

Figure 73: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 18:01:23 and 18:04:23 to a maximum range of about 38.6 km

82 DRDC Ottawa TM 2013-152

Figure 74: ADS-B (blue) and radar tracks (white) for an Air Canada Boeing-767-35H (ER) observed taking off from Ottawa International Airport on 18 Sept. 2010. Except for a brief gap (17:37:44 to 17:38:51) the radar tracked it between 17:34:47 and 17:40:40 at a maximum range of about 35.7 km. The gap is probably due to the aircraft being outside the radar’s main beam.

DRDC Ottawa TM 2013-152 83

Figure 75: Google Earth views showing where the flight path of the Boeing-767-35H (ER) shown in Figure 74 intersects with the nominal 12° cone swept by the radar beam.

Figure 76: Flight path (red dashed line) of Air Canada flight 838 (ID: C0584D) relative to the ground clutter in the vicinity of the radar site. The range rings in the image are at increments of 8 km.

84 DRDC Ottawa TM 2013-152

Figure 77: ADS-B (red) and radar tracks (light blue) for a WestJet Boeing-737-7CT/W observed taking off from Ottawa International Airport on 18 Sept. 2010. The radar tracked it between 14:48:57 and 14:52:26 to a maximum range of about 33.6 km

DRDC Ottawa TM 2013-152 85

86 DRDC Ottawa TM 2013-152

Figure 79: Miscellaneous radar tracks recorded for 18 Sept. 2010. None of these tracks had an associated ADS-B track so they could not be identified. The maximum range of any detected aircraft was 42.1 km.

DRDC Ottawa TM 2013-152 87

5 Conclusions

The following observations and conclusions can be made about the ability of the Rutter 100S6 radar system to detect and track aircraft in good weather conditions.

2) The detection range of the aircraft depends on the type, size and aspect angle:

a. Small low winged aircraft can be detected and tracked to a maximum range of about 15 km when viewed tail-on.

b. Larger aircraft the size of the PBY-5A Canso or the Lancaster Mark X can be detected and tracked to a range of just over 30 km when viewed tail-on.

c. Large commercial airliners such as the Boeing 737-300 can be seen for brief periods at ranges of up to 50 km when viewed at an optimal angle of broadside, and within the main beam of the radar antenna. At other times, it can usually be detected and tracked to ranges between 30 and 35 km.

d. Very large aircraft such as the Boeing 767 and Airbus A320 or A330 can usually be detected to a range of 40 km regardless of aspect angle and up to 50 km when seen broadside.

7) Unless the aircraft maintains a relatively straight bearing, the alpha-beta tracker that comes with the radar system has difficulty maintaining a track lock. This is expected since the radar was originally intended as a marine navigation aid to detect and track relatively slow moving marine targets. The aircraft observed in these trials had airspeeds that usually exceeded 150kph and went as high a 600kph. At such speeds, manoeuvring aircraft are difficult to track because the radar only has a maximum update rate of about 1.3 seconds between rotational scans (48 rpm). These problems are exacerbated when the aircraft is at a range and aspect where there are a significant number of missed detections conflicting with the required tracking criteria (e.g. M-of-N detection parameter). A more advanced tracking algorithm would probably provide better results, especially if the tracking was not required to be in real-time.

3) Initiating a track in heavy ground clutter (especially in Long Range mode) near the radar site with the current signal processing and tracker is generally not possible. As seen with the screen captures shown in Section 4.1, this can limit the tracking capability to ranges beginning at more than a kilometre from the radar site in reasonably flat terrain. However, in general, the ground clutter is highly terrain dependent and may be reduced if the radar is located on ground that is higher than the surrounding terrain, with a relatively sharp drop off in all directions.

88 DRDC Ottawa TM 2013-152

4) Maintaining a track through areas of heavy ground clutter can be problematic, and depends on the speed of the aircraft and the width of the clutter area with respect to the track.

5) The results obtained in these experiments are consistent with the SIESTA predictions that a high-winged aircraft the size of a DHC-6 Twin-Otter might be seen by Rutter 100S6 radar up to a distance of over 30 km, as long as it is broadside to the radar beam.

While ADS-B reports from aircraft are generally accurate, they cannot always be relied upon to provide a true report. Over the period of the trials, at least one Air Canada B767-38E(ER) passenger aircraft (ID: C04EB6, Callsign: ACA839) on 11 Aug. had a positional offset of about 12 km to the West and between 1 and 2 km to the South. Another aircraft reported its location incorrectly because it was providing a random longitude with each report. This latter problem might be mitigated by a direction finding system to intercept the ADS-B signal.

In August of 2008, during sensor trials attempted at Gascoyne Inlet, the author used an ADS-B receiver to collect reports from aircraft flying over the area. Despite the fact that the receiver was located in a valley between two mesas over 200m high and separated by less than 3 km, it was still able to collect reports from about one hundred aircraft over the course of two weeks while recording for only eight to ten hours per day. Some of the aircraft reports were from as far as 350 km away. As shown in Figure 80, at least six passenger aircraft flew within 50 km of the Gascoyne site and at least half of those were within 40 km. As shown in Table 4 these aircraft were of a type and size similar, or larger than seen in the GEA trials.

DRDC Ottawa TM 2013-152 89

Figure 80: ADS-B reports from commercial passenger flights over the Gascoyne Inlet area in Aug. 2008.

Table 4: Aircraft types observed and recorded by ADS-B within 50 km of the Gascoyne Inlet test site during field trials in 2008

ICAO24 ID Callsign Altitude (ft) Aircraft type Airline

C0234E ACA087 34000 B777-233(LR) Air Canada

C023AA ACA088 37000 B777-233(LR) Air Canada

4001A9 AFL321 31850 B767-38A(ER) Aeroflot

A1426F UAL897 36000 B747-422 United Airlines

A1426F UAL895 32000 B747-422 United Airlines

90 DRDC Ottawa TM 2013-152

780205 CPA841 34000 B777-367(ER) Cathay Pacific

Based on the results shown in earlier sections, it is reasonable to conclude that the Rutter 100S6 radar system may be able to occasionally detect and track commercial airliners for brief periods of time depending on their aspect, range, and altitude. It should also be able to detect and possibly track aircraft like the DHC-6 Twin Otter up to a range of approximately 30 km.

DRDC Ottawa TM 2013-152 91

92 DRDC Ottawa TM 2013-152

References .....

[1] Kerr, D. E. Ed., Propagation of Short Radio Waves, McGraw-Hill, New York, 1951, Section 2.2, page 35 [2] Briggs, John N., Target Detection by Marine Radar- IEE radar, sonar, navigation and avionics series 16, London : Institution of Electrical Engineers, 2004, Section 2.8, pp 88-99 [3] Meeks, M. L., Radar Propagation at Low Altitudes, Artech House Inc., 1982, pg 24 [4] David Lynch Jr., Introduction to RF Stealth, Scitech Publishing, 2004, pg 35, [5] Fuhs, A., Radar Cross Section Lectures, Naval Post Graduate School, 1984. [6] Howell, N. A., Design of Pulse Gated Compact Radar Cross Section Range, 1970 G-AP Int. Prog. & Dig. IEEE Public. 70c 36-AP, September 1970, pp 187-195 [7] Schleher, Curtis, Electronic Warfare in the Information Age, Boston, Artech House, 1999, page 511 [8] Yildirim, Zeki, Thesis-Self-Defense of Large Aircraft, Naval Postgraduate School, Monterey California, March 2008, page 45. [9] Hazlett, M., Andersh, D., Lee, S. W., Ling, H., Yu, C. L. , XPATCH: a high-frequency electromagnetic scattering prediction code using shooting and bouncing rays, Proc. SPIE Vol. 2469, June 1995, p. 266-275, Targets and Backgrounds: Characterization and Representation, Wendell R. Watkins; Dieter Clement; Editors [10] M.G.E. Brand. Radar signature analysis and prediction by physical optics and ray-tracing.The RAPPORT code for RCS prediction. Technical Report FEL–95–A097, TNO-FEL, 1995. [11] Wong, S., Validation of the electromagnetic code FACETS for numerical simulation of radar target images, Technical Memorandum, DRDC Ottawa TM 2009-275, December 2009, 46 pages. [12] Ridenour, L.N. (ed.): Radar System Engineering, MIT Radiation Laboratory Series, Vol. 1, McGraw-Hill Book Company, New York, 1947, page 76 [13] Skolnik, M. I (ed.)., Radar Handbook-Second Edition, McGraw-Hill Publishing Co., 1990, page 11.16 [14] Glossary for Pilots and Air Traffic Services Personnel, Revision No. 21,JULY 2012,TP 11958E,(07/2012),TC-1004759, www.tc.gc.ca/eng/civilaviation/opssvs/secretariat- terminology-glossary-215.htm#general_aviation accessed 25 July 2012 [15] Vintage Wings of Canada, Copyright 2010, Wings over Gatineau Air Show, http://envol.vintagewings.ca/ , accessed 27 Oct. 2010 [16] Fly Day: 52 Annual event organized by the Ottawa Flying Club and the Ottawa Rotary Club, Last update: 12 Sept. 2010, Web-Host: LaneChange.net, http://flyday.ca/?p=390, accessed 13 April 2011 [17] Gunston, B., Classic World War II Aircraft Cutaways, Bounty Books; New Edition 28 Oct. 2011, page 74

DRDC Ottawa TM 2013-152 93

This page intentionally left blank.

94 DRDC Ottawa TM 2013-152

Annex A Estimation of Aircraft RCS

Figure A-1: Basic structural elements for estimating an aircraft RCS (not in order of importance). The RCS of a sphere (not shown) is RCS=πD2/4 where D is the diameter and is independent of angle and frequency. Trihedral corners were not expected in an aerodynamic airframe, so were not included.

DRDC Ottawa TM 2013-152 95

Figure A-2: Measurements for the Boeing 737-600 passenger aircraft leading to the RCS estimates listed in Table A-.The areas outlined in white show how the RCS elements relate to the actual airframe (nose, wing edges, and engines omitted).

96 DRDC Ottawa TM 2013-152

Figure A-3: RCS model for the B737-600 showing the elements listed in Table A-.

Table A-1: Elements contributing to a rough estimate for the RCS of a Boeing 737-600

Component Dimension 1(m) Dimension 2(m) Maximum RCS (dBsm)

Main Fuselage 19.43 (length) 2.73 (radius) 53.08 Tail Fuselage 6.22 (length) 1.365 (radius) 40.18 Main Wing Dihedral 5.44 (length) 1 (height) 58.65 Vertical Stabilizer 6.22 (width) 7.77 (height) 71.60 Tail-wing edge 7.77 NA 12.8 Main Wing Edge 17.1 NA 19.7 Nosecone* 1 5 * The nosecone calculation assumes the cone (negligible contribution) is tipped by a hemisphere with a radius of 1m

DRDC Ottawa TM 2013-152 97

Figure A-4: Measurements for the DHC-6 Twin Otter that lead to the RCS estimates provided in Table A-2. The areas outlined in red show how the RCS elements relate to the actual airframe (nose, wing edges, and engines omitted).

Table A-2: Elements contributing to a rough estimate for the RCS of DHC-6 Twin Otter

Component Dimension 1 Dimension 2 Maximum RCS (dBsm)

Main Fuselage 5.5m(length) 2 m (height) 46.8 Tail Fuselage 2.8 m (length) 1.3 m (radius) 33.0 Main Wing Dihedral 2.2m 1.7m 55.4 Vertical Stabilizer 7.56 m2 NA 58.5 wing Tail-wing edges 6 m NA 10.6 Main Wing Edges 17.4 m NA 19.8 Nosecone 0.5 2

98 DRDC Ottawa TM 2013-152

el perspectives at at perspectives el on aspect. The images on the left are CAD mod are CAD left on the images The on aspect. - 29 at near nose near 29 at - : Radar Cross Section of a MIG a of Section Cross : Radar 5 - from FACETS as a function of azimuth. The jet engine intakes at nose on increases the RCS by at least 10 dBsm 10 dBsm least at by the RCS increases on nose at intakes engine jet The of azimuth. a function as from FACETS Figure A Figure zero degrees azimuth and a pitch of 0 and five degrees respectively. The plots on the right are the respective RCS prediction RCS respective the are right the on plots The respectively. five degrees 0 and of pitch a and azimuth zero degrees

DRDC Ottawa TM 2013-152 99

This page intentionally left blank.

100 DRDC Ottawa TM 2013-152

Annex B Rutter 100S6 Radar System Specifications and SIESTA Set-up

Table B-3: System Description

Radar Parameter Description Radar Parameter Value(s) RF Amplifier Type Magnetron (non-coherent) RF Carrier Frequency 9410±30 MHz (X-Band) Horizontal Beam Width, -3dB ( max.) 1.0° Antenna Size 2.4m (8 ft) Bearing Discrimination 1.0° Sidelobes within 10° of Beam (min.) -23dB Sidelobes outside 10° of Beam (min.) -30dB Gain (nominal) 31 dB Polarization Horizontal Maximum wind (speed) load 185 kph (100 knots) Rotation Speed 28 or 45 rpm Magnetron Peak Output Power (nominal) 25 kW Receiver type Logarithmic with Low Noise Front End (LNFE) Intermediate Frequency (IF) 60 MHz (centre) Noise Factor 5 dB Dynamic Range (nominal) 80 dB Maximum Input Power 370 VA IF Band Width 20 MHz for short and medium range pulses 30 MHz for long range pulses Transmit Modes Pulse Length Pulse Maximum Repetition Unambiguous Frequency Range, Ru (PRF) (km) Short Range 0.05 μs 3000 Hz 50.0 Medium Range 0.25 μs 1800 Hz 83.3 Long Range 0.75 μs 785 Hz 191

Table B-4: Mechanical Dimensions: Component Height Depth Width Weight (mm) (mm) (mm) (kg) X-band Scanner Unit with 2.4m 440 586 2550* 55 47‡ Antenna * Antenna turning circle diameter ‡ Excluding Transceiver

DRDC Ottawa TM 2013-152 101

Cape Cape Liddon, was about 300m ASL. Also, for the scenarios used in this report, the METEO : Typical set of parameters for running SIESTA; unless the “ASL” box is checked, the software assumes the 1 - Figure Figure B antenna height is with respect to the terrain height for that geographic location (latitude and longitude)which, for this specific location on top of calculations. the into factor did not and available, not file were the HPAC including data,

102 DRDC Ottawa TM 2013-152

up up parameters -

des. des. Terrain Terrain Elevation Data (DTED) or Canadian Digital Elevation Data (CDED)

hot” representing the highest altitu highest the representing hot” - s an example of the “RF Situational Display Main Control Panel” where additional set : This i 2 -

Figure B such as CAPPI height (i.e. “Height ASL”) are input to SIESTA. The image on the extreme right is a “thumbnail” of the terrain elevation (obtained from Digital files) centred on the specified “RADAR LOCATION”. In general, “red and ocean, the representing darker colours represent lower altitudes, with blue

DRDC Ottawa TM 2013-152 103

Annex C Aircraft Observed at the Gatineau Executive Airport from 29 July to 19 Sept. 2010.

Table C-1: List of aircraft observed visually, and photos collected, to ground truth the radar data recorded during the trials. Aircraft types were often confirmed by looking up the wing number in internet databases (provided in the last column); otherwise, a best guess was used.

Wing No. Wing No. Propulsion Date Time Aircraft Type Photo No. Comments type Engines (hh:mm) /references

www.airframes.org C-GBLT Low 2 Propeller 30 Jul. 14:51 Piper Cherokee 101_1808.jpg

C-GBLT Low 2 Propeller 30 Jul. 15:10 Piper Cherokee 101_1810.jpg www.airframes.org

High 1 Propeller 30 July 15:35 visual High 1 Propeller 30 Jul. 12:24 Beaver float plane? DSCF1258.jpg C-GRKC High 1 Propeller 06 Aug. 13:57 Cessna 152 visual www.airport-data.com www.airport- C-GUFW High 1 Propeller 06 Aug. 14:06 Cessna 150L visual data.com/aircraft/C- GUFW.html DSCF1329.jpg Unknown Low 2 Propeller 06 Aug. 17:54 Unknown DSCF1329b.jpg Bell 206A 100_1124.jpg C-FCGO Rotary 2 Propeller 11 Aug. 14:04 www.rotorspot.nl/c-1.htm JetRanger 100_1124b.jpg IMG_0042.jpg IMG_0042b.jpg C-FDGO? Rotary 2 Propeller 11 Aug. 14:07 Bell 206A Movie clip MVI_0043.avi High 2 Propeller 11 Aug. 15:01 Geo-phys. MVI_0047b.jpg Landing approach from west High 2 Propeller 11 Aug. 15:12 Geo-phys MVI_0054b.jpg Landing approach from west www.airliners.net/search/photo.sea C-GTHY High 1 Propeller 11 Aug. 15:51 Aviat A-1B Husky MVI_0067b.jpg rch?regsearch=C-GTHY Unknown Propeller 11 Aug. 15:30 Bell 206 IMG_0062.jpg 104 DRDC Ottawa TM 2013-152

Wing No. Wing No. Propulsion Date Time Aircraft Type Photo No. Comments type Engines (hh:mm) /references Unknown IMG_0060.jpg High 1 Propeller 11 Aug. 15:35 Cessna? IMG_0060b.jpg C-GTHY Propeller 11 Aug. 16:00 Aviat A-1B Husky IMG_0068.jpg C-GTHY High 1 Propeller 11 Aug. 16:05 Aviat A-1B Husky IMG_0071b.jpg IMG_0072.jpg Unknown High 1 Propeller 11 Aug. 16:15 Cessna? IMG_0072b.jpg abpic.co.uk/photo/1241245/ Diamond DA-20- MVI_0094b.jpg C-FWSH Low 1 Propeller 11 Aug. 17:39 abacuspub.com/fsd/catalog/s55 A1 Katana MVI_0094c.jpg 0.htm (specs) Unknown High 1 Propeller 11 Aug. 17:36 Cessna? N/A Visual observation IMG_0027.jpg www.myaviation.net/search/pho Pacific Aerospace IMG_0027b.jpg to_search.php?id=01470439 ZK-XLB Low 1 Propeller 11 Aug. 13:25 750XL MyAviationNetPh aerospace.co.nz/aircraft/p-750- (NZ) otoID01470439.jp xstol/description g Movie clip Unknown Biplane 1 Propeller 11 Aug 13:40 Unknown MVI_0031.avi Unknown Rotary 2 Propeller 11 Aug. 13:50 Bell 306? IMG_0036.jpg Unknown 100_1158.jpg High 1 Propeller 11 Aug. 15:40 Trainer 100_1158b.jpg www.abpic.co.uk/photo/125034 Bell 206A 100_1159.jpg C-FDOC Rotary 2 Propeller 11 Aug 15:41 JetRanger 100_1159b.jpg 6/no_pictures.php (Dept. of Transport) Supercub C-GCEL Low? 1 Propeller 11 Aug. 14:19 visual www.supercub.org/phpb PA-18a (18-4333) Unknown Low 2 Propeller 11 Aug. 14:28 Piper Cherokee IMG_0044.jpg Unknown T-33 Turbo See above Low 2 Twin jet 17 Sept 14:42 IMG_0256b.jpg (Shooting Star?) Unknown T-33 Turbo See above Low 2 Twin jet 17 Sept 14:43 100_1320b.jpg (Shooting Star?)

DRDC Ottawa TM 2013-152 105

Wing No. Wing No. Propulsion Date Time Aircraft Type Photo No. Comments type Engines (hh:mm) /references Unknown barnstormers.com/eFLYER/200 9/062-eFLYER-FA01- T-33 Turbo Low 2 Twin jet 17 Sept 14:46 100_1323b.jpg stars.html (Shooting Star?) t33heritagefoundation.org/Aircr aft.php Unknown T-33 Turbo See above Low 2 Twin jets 17 Sept. 14:47 100_1330b.jpg (Shooting Star?) Unknown T-33 Turbo 100_1333b.jpg See above 17 Sept. 14:48 (Shooting Star?) 100_1332b.jpg Unknown T-33 Turbo See above 17 Sept. 14:56 100_1338b.jpg (Shooting Star?) 2866 Low 1 Propeller 18 Sept 13:53 Harvard IMG_0362b 2866 Low 1 Propeller 18 Sept 13:53 Harvard IMG_0363b Mustang passion- CF-VPM Low 1 Propeller 18 Sept. 14:10 (Mustang Mk. IV, IMG_0366b.jpg aviation.qc.ca/vintagewings_08.ht 1944) m Low 1 Propeller 18 Sept 14:46 Harvards MVI_0375b 3 flying in formation Unknown passion- Low 1 Propeller 18 Sept 14:48 Harvard IV, 1952 100_1383b.jpg aviation.qc.ca/vintagewings_08.ht m Unknown passion- Low 1 18 Sept 14:51 Harvard(s) 100_1385b.jpg aviation.qc.ca/vintagewings_08.ht m flickr.com/photos/djipibi/50044 C-FKFC Low 1 Propeller 18 Sept. 14:51 Ryan Navion IMG_0260b.jpg 45454/ Low 1 Propeller 18 Sept. 14:54 Harvards IMG_0381b 2 flying NE over runway Low 1 Propeller 18 Sept. 14:56 Harvard IMG_0385b Flying manoeuvres over runway Low 1 Propeller 18 Sept. 14:57 Harvards IMG_0386b 2 flying manoeuvres over runway Harvards IMG_0388b 3 wingtip to wingtip manoeuvres Low 1 Propeller 18 Sept. 14:58 IMG_0389b 3 in formation NE over runway Low 1 Propeller 18 Sept. 15:01 Harvards IMG_0390b 3 flying in formation F86-E Sabre 5, Low 1 Jet 18 Sept 15:11 IMG_0391b 1954

106 DRDC Ottawa TM 2013-152

Wing No. Wing No. Propulsion Date Time Aircraft Type Photo No. Comments type Engines (hh:mm) /references T-33 Turbo See above Unknown Low 2 Twin jets 18 Sept 15:21 IMG_0399b.jpg (Shooting Star?) passion- F86-E Sabre 5, C-GSBR Low 1 Jet 18 Sept 15:33 IMG_0407b.jpg aviation.qc.ca/vintagewings_08.ht 1954 m passion- Unknown High 2 Propeller 18 Sept 15:57 PBY-5A Canso MVI_0412b.jpg aviation.qc.ca/vintagewings_08.ht m passion- Unknown Low 4 Propeller 18 Sept. 15:58 Lancaster Mark X 100_1402b.jpg aviation.qc.ca/vintagewings_08.ht m Unknown Low 4 Propeller 18 Sept. 15:58 Lancaster Mark X MVI_0413b.jpg See above Corsair passion- C-GVWC Low 1 Propeller 18 Sept 15:58 FG-1D Corsair, MVI_0414b.jpg aviation.qc.ca/vintagewings_08.ht 1945 m Unknown Lancaster with Corsair escort Low 4 Propeller 18 Sept. 16:24 Lancaster Mark X 100_1408a,b,c flying westward, over runway Unknown FG-1D Corsair, See above Low 4 Propeller 18 Sept. 16:24 100_1408a,b,c 1945 Unknown passion- 100_1412b.jpg Low 4 Propeller 18 Sept 16:30 Lancaster + escort aviation.qc.ca/vintagewings_08.ht 100_1413a.jpg m Unknown Low 4 Propeller 18 Sept 16:41 Lancaster 100_1414a.jpg over NE treetops Unknown Low 4 Propeller 18 Sept 16:45 Lancaster 100_1415a.jpg over NW treetops Unknown 16:45:3 over N over firing range Low 4 Propeller 18 Sept Lancaster 100_1416a.jpg 4 Unknown High 2 Propeller 18 Sept 16:53 PBY-5A Canso 100_1417b.jpg Heading west away from airport Unknown Low 1 Propeller 18 Sept 17:22 Unknown 100_1418b.jpg Unknown High 1 Propeller 18 Sept 17:23 Unknown 100_1419b.jpg Beech TC-45G See below Expeditor, N7826L Unknown Low 2 Propeller 18 Sept 17:27 100_1420b.jpg / GTMO BAY - 086

DRDC Ottawa TM 2013-152 107

Wing No. Wing No. Propulsion Date Time Aircraft Type Photo No. Comments type Engines (hh:mm) /references flickr.com/photos/adammooz/5 Beech TC-45G 039435420/in/set- Expeditor, N7826L 72157624941987229/ Unknown Low 2 Propeller 18 Sept 17:27 100_1422b / GTMO BAY - flickr.com/photos/adammooz/5 086 039574904/in/set- 72157624941987229/ airliners.net/search/photo.search?ai C-GGYY Low 1 Propeller 18 Sept. 17:37 S45 Mark II 100_1436b.jpg rcraft_genericsearch=Partenair%20 S-45%20Mystere North American T- jetphotos.net/showphotos.php?regs C-FWGA Low 1 Propeller 18 Sept 17:38 100_1438b.jpg 6G Harvard 4 earch=C-FWGA 100_1443b.jpg 100_1444b.jpg Unknown Low 1 Propeller 18 Sept. 17:40 Unknown 100_1445b.jpg 100_1446b.jpg 100_1447b.jpg Unknown Low 1 Propeller 18 Sept. 17:41 Unknown 100_1448b.jpg 100_1449.jpg Unknown Low 1 Propeller 18 Sept. 17:42 Unknown 100_1450.jpg 1948 Ryan Navion 100_1451.jpg www.airport–data.com C-GWIY Low 1 Propeller 18 Sept. 17:42 C/N Nav-41589 100_1452.jpg www.passion-aviation.com 1948 Ryan Navion 100_1453.jpg www.airport–data.com C-GWIY Low 1 Propeller 18 Sept. 17:43 C/N Nav-41589 www.passion-aviation.com passion- C-GWIY Low 1 Propeller 18 Sept. 17:43 Ryan Navion, 1948 100_1454b.jpg aviation.qc.ca/vintagewings_08.ht m Unknown Low 1 Propeller 18 Sept. 17:44 unknown 100_1456b.jpg 1964 Mooney M- intelair.ca/aircraft.php C-FCBE Low 1 Propeller 18 Sept 17:44 100_1457b.jpg 20E (Super 21), airliners.net 100_1458b.jpg airliners.net 100_1459b.jpg C-FIRS Low 1 Propeller 18 Sept. 17:45 2001 Europa XS flickr.com 100_1460b.jpg airport-data.com/aircraft/C- 100_1461b.jpg FIRS.html

108 DRDC Ottawa TM 2013-152

Wing No. Wing No. Propulsion Date Time Aircraft Type Photo No. Comments type Engines (hh:mm) /references Unknown High 1 Propeller 18 Sept. 17:46 Unknown 100_1464b.jpg 100_1465b.jpg Unknown Low 1 Propeller 18 Sept. 17:46 Unknown 100_1466b.jpg 100_1467b.jpg Unknown High 1 Propeller 18 Sept. 17:46 Unknown 100_1468b.jpg 100_1469b.jpg Unknown High 1 Propeller 18 Sept 17:47 Unknown 100_1470b.jpg 100_1472b.jpg Unknown Low 1 Propeller 18 Sept 17:47 Unknown 100_1474b.jpg Unknown High 1 Propeller 18 Sept 17:48 Unknown 100_1475b.jpg 100_1476b.jpg Unknown High 1 Propeller 18 Sept 17:48 Unknown 100_1477b.jpg Unknown High 1 Propeller 18 Sept 17:49 Unknown 100_1478b.jpg Unknown Low 18 Sept 17:49 Unknown visual Unknown Low 18 Sept 17:50 Unknown visual Unknown Low 2 Propeller 18 Sept. 18:15 Unknown IMG_0440 Unknown Low 2 Jet 18 Sept. 18:20 Unknown MVI_0446b.jpg Unknown Low 2 Jet 18 Sept 18:21 Unknown 100_1479b.jpg Unknown Low 1 Propeller 18 Sept. 18:32 Unknown 100_1480b.jpg 100_1481b.jpg

Note: the rows shaded in red indicate times when the radar was not active.

DRDC Ottawa TM 2013-152 109 C.1 Time-stamped Photographs of Small and Medium Sized Aircraft Observed at GEA.

The following are sets of photographs of small and medium sized fixed-wing and rotary-winged aircraft that were observed at the GEA during the period of the radar system trials. The photographs are ordered sequentially by time and date for each day of the trials.

C.1.1 30 July 2010

Figure C-1: Photographs of two aircraft observed on 30 July 2010: a Beaver float plane in the upper left, and a fly-over by a Piper Cherokee.

110 DRDC Ottawa TM 2013-152 C.1.2 6 August 2010

Figure C-2: Photographs of aircraft observed between 9:42:53 and 14:49:25 on 6 Aug. 2010.

DRDC Ottawa TM 2013-152 111 C.1.3 11 August 2010 icopter icopter in the vicinity of the GEA throughout the day hel

Bell Bell 206A JetRanger

: Photographs of a 3 - Figure Figure C on 6 Aug. 2010.

112 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-4:: Photographs of aircraft observed between 13:25:34 and 17:39:30 on 11 Aug. 2010. 113

C.1.4 17 September 2010

Photographs Photographs of aircraft observed between 14:17:58 and 14:47:44 on 17 Sep. 2010. This included several photos of a

: 5 - Figure Figure C flyovers. during Jet T33 Turbo

114 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-6: Photographs of aircraft observed between 14:48:03 and 14:51:31 on 17 Sep. 2010 115

: Photographs of aircraft observed between 14:52:19 and 17:46:56 on 17 Sep. 2010. on 17:46:56 and 14:52:19 between observed aircraft of : Photographs 7 - Figure C Figure

116 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-8: Photographs of aircraft observed between 17:47:23 and 17:56:12 on 17 Sep. 2010. 117

. 2010

and 19:15:58 on 17 Sep. on 19:15:58 and

: Photographs of aircraft observed between 18:32:09 between observed aircraft of : Photographs 9 - Figure C Figure

118 DRDC Ottawa TM 2013-152 C.1.5 18 September 2010

: Photographs of aircraft observed between 13:53:20 and 14:34:25 on 18 Sep. 2010 18 Sep. on 14:34:25 and 13:53:20 between observed of aircraft : Photographs 10 - Figure C Figure

DRDC Ottawa TM 2013-152 119

of aircraft observed between 14:47:017and 15:11:11 on 18 Sep. 2010 18 Sep. on 15:11:11 14:47:017and between observed of aircraft Photographs Photographs

: 11 - Figure C Figure

120 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-12: Photographs of aircraft observed between 15:16:35 and 15:29:01 on 18 Sep. 2010. Most of the photos were of an F86-E Sabre jet except for the one in the upper left where it was flying in formation with a T33 Shooting Star and the second 121 photo of the T33 in the bottom row.

5A Canso. - rved rved between 15:31:16 and 15:58:408on 18 Sep. 2010. The aircraft included an : Photographs of aircraft obse 13 - E Sabre Jet, a Lancaster Mark X bomber and a PBY and X bomber Mark a Lancaster Jet, E Sabre - Figure Figure C F86

122 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-14: Photographs of aircraft observed between 15:58:31 and 16:41:32 on 17 Sep. 2010. The aircraft included a Corsair, and a Lancaster flying separately and in formation with other WW II fighters. 123

Sep. 2010 Sep.

8 on 1 on

10 : 29 : 7 and 1 and

0 :0 45 : 6 : Photographs of aircraft observed between 1 between observed of aircraft : Photographs 15 - Figure C Figure

124 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-16: Photographs of aircraft observed between 17:29:22 and 17:38:44 on 18 Sep. 2010 125

ircraft observed between 17:38:40 and 17:42:47 on 18 Sep. 2010 18 Sep. on 17:42:47 and 17:38:40 between observed ircraft : Photographs of a : Photographs 17 - Figure C Figure

126 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-18: Photographs of aircraft observed between 17:42:51 and 17:45:56 18 Sep. 2010 127

Photographs of aircraft observed between 17:46:06 and 17:48:08 on 18 Sep. 2010 18 Sep. on 17:48:08 and 17:46:06 between observed of aircraft Photographs

: 19 - Figure C Figure

128 DRDC Ottawa TM 2013-152 DRDC Ottawa TM 2013- TM Ottawa DRDC 152

Figure C-20: Photographs of aircraft observed between 17:48:11 and 18:31:51 on 18 Sep. 2010 129

Annex D Aircraft Specifications

Table D-1: Specifications for aircraft observed during the GEA trials, as well as some “Arctic” aircraft Aircraft Type/Model Aircraft Measurements ordered by Wing Area (ADS-B data, possibly including date of observation)

Length Wing- Wing Height Empty Ceiling Cruising Max (ft) span Area (ft) Weight (ft) Speed Speed (ft) (ft²) (lb) (mph) (mph)

Cessna 152 24.1 32.7 157 8.5 1104 14700 122 174

Cessna 185 25.6 35.9 174 7.8 1708 17150 169 210 (Skywagon) Cessna 172 27.2 36.1 174 8.9 1700 14000 134 (Skyhawk)

Mooney 20E 26.75 36.42 175.7 8.17 2370 25000 272 278

DHC-2 Beaver 30.2 47.9 250 8.86 2992 15000 143 158

Beech TC-45G 34.17 47.67 349 9.67 6175 26000 160 225 Expeditor 12500 Twin Otter 90 to 51.75 65 420 19.5 8100 (without 175 (DHC-6 300 series) 175 oxygen) DHC-8-102 Dash 8 24.6 (tail) (C04A7D_NVC302_ 73 84.9 586 8.8 (fus- 23111 25000 310 30july C-GCFK elage) NavCanada)

ATR42-300 74.4 80.6 587 24.9 24802 25000 350

Dash 8-300 84.25 90 605 24.58 23111 15000 330

Martin B-26 58.25 71 658 21.5 21375 25000 315 Marauder Bomber

CRJ-705 119 4 81.5 760 24.58 47505 41000 548

Embraer 190 118.92 85.25 996 34.67 61900 35000 504 (regional)

130 DRDC Ottawa TM 2013-152 PBY-5A Canso 63.88 104 1400 20.17 20910 14700 117 179

Airbus 111 111.83 1318 38.58 90000 35000 520 A319_100 A320-212 (ADECAB 499AG 123.3 111.9 1320 38.5 (tail) 94000 39000 511 537 N997AG? US?) B737-6CT (C07F0D C-GWCY WestJet 6Aug) 102.5 112.5 1344 41.3 (tail) 80200 41000 514 588 (C08096_697, C-GWSB WestJet 18 Sept.) B737-7CT/W (C0669E, C-GMWJ, WestJet, 17 Sept.) (C07E62 C-GVWJ WestJet) (C07FB1 C-CWJG WestJet) (C080A9 C-GWSU WestJet) 110.3 117.5 1344 41.3 (tail) 83000 41000 514 588 (C0121E C-FGWJ WestJet) (C03472 C-FTWJ WestJet) (C0712E C-GQWJ WestJet 30July) (C01766 C-FIWJ WestJet 11Aug.) 17.9 Boeing 767-300ER 180.25 156 3050 (fuselage) 198440 41000 530 568 52(tail) Boeing 767-322ER 17.9 (A8B0B3_UAL949 180.3 156 3050 (fuselage) 198440 41000 530 568 N661UA United 52(tail) Airlines) Boeing B767-375 (ER) 17.9 (C0054A C-FCAB 180.3 156 3050 (fuselage) 198440 41000 530 568 Air Canada) 52(tail)

B767-35H (ER) (C0584D C-GHLK 17.9 Air Canada) 180.3 156.1 3050 (fuselage) 198440 41000 530 568 (4CA1DD_AZA650 52(tail) Centennial Aviation Ireland)

DRDC Ottawa TM 2013-152 131 B767-38E (ER) (C04EB6 ACA838 17.9 AirCanada C-GDUZ 180.3 156.1 3050 (fuselage) 198440 41000 530 568 11Aug) 52 (tail)

A330-343 (c051e2_ACA889 193 197 3892 55.3 (tail) 274000 41000 537 563 Air Canada C-GFAF 11aug) Airbus A330-343X (C05840 C-GHKX 193 197 3892 55.3 (tail) 274000 41000 537 563 Air Canada 30July) 61 (tail) 557 Boeing 777-200LR 209 212.6 4605 20.3 (fuse- 320000 35000 lage)

132 DRDC Ottawa TM 2013-152

List of abbreviations/acronyms

ADS-B Automatic Dependent Surveillance- Broadcast ASL Above (mean) Sea Level AIS Automatic Identification System ATC Air Traffic Control AWS Above Water Sensor CANDISS Canadian Arctic Night and Day Imaging Sensor System CAPPI Constant Altitude Plan Position Indicator DND Department of National Defence DRDC Defence Research & Development Canada DRDKIM Director Research and Development Knowledge and Information Management EAA Experimental Aircraft Association EO Electro-optic ER Extended Range GA General Aviation GAS Gatineau Air Show GEA Gatineau Executive Airport GIS Geographic Information System GPS Global Positioning System ICAO International Civil Aviation Organization IFF Identification Friend or Foe IR Infrared MRL Mobile Radar Lab NW Northern Watch OIA Ottawa International Airport (a.k.a. MacDonald-Cartier International) RAPPORT Radar-signature Analysis and Prediction by Physical Optics and Ray Tracing RCS Radar Cross Section RDS Rapidly Deployable System

DRDC Ottawa TM 2013-152 133

R&D Research & Development SIESTA Scenario Integrated Environment for Tactics and Awareness SAC Site Antenna Committee SOLAS Safety Of Life At Sea SSR Secondary Surveillance Radar TDP Technology Demonstration Program VHF Very High Frequency UWS Under Water Sensor/system WFOV Wide Field of View

134 DRDC Ottawa TM 2013-152 DOCUMENT CONTROL DATA (Security classification of title, body of abstract and indexing annotation must be entered when the overall document is classified) 1. ORIGINATOR (The name and address of the organization preparing the document. 2. SECURITY CLASSIFICATION Organizations for whom the document was prepared, e.g. Centre sponsoring a (Overall security classification of the document contractor's report, or tasking agency, are entered in section 8.) including special warning terms if applicable.)

Defence R&D Canada – Ottawa UNCLASSIFIED 3701 Carling Avenue (NON-CONTROLLED GOODS) Ottawa, Ontario K1A 0Z4 DMC: A REVIEW: GCEC October 2013

3. TITLE (The complete document title as indicated on the title page. Its classification should be indicated by the appropriate abbreviation (S, C or U) in parentheses after the title.)

Northern Watch: Air Surveillance with a Rutter 100S6 Radar System- Trials Analysis and Results

4. AUTHORS (last name, followed by initials – ranks, titles, etc. not to be used)

Brookes, D.

5. DATE OF PUBLICATION 6a. NO. OF PAGES 6b. NO. OF REFS (Month and year of publication of document.) (Total containing information, (Total cited in document.) including Annexes, Appendices, etc.) November 2013 164 17

7. DESCRIPTIVE NOTES (The category of the document, e.g. technical report, technical note or memorandum. If appropriate, enter the type of report, e.g. interim, progress, summary, annual or final. Give the inclusive dates when a specific reporting period is covered.)

Technical Memorandum

8. SPONSORING ACTIVITY (The name of the department project office or laboratory sponsoring the research and development – include address.)

Defence R&D Canada – Ottawa 3701 Carling Avenue Ottawa, Ontario K1A 0Z4

9a. PROJECT OR GRANT NO. (If appropriate, the applicable research 9b. CONTRACT NO. (If appropriate, the applicable number under and development project or grant number under which the document which the document was written.) was written. Please specify whether project or grant.)

15ej

10a. ORIGINATOR'S DOCUMENT NUMBER (The official document 10b. OTHER DOCUMENT NO(s). (Any other numbers which may be number by which the document is identified by the originating assigned this document either by the originator or by the sponsor.) activity. This number must be unique to this document.)

DRDC Ottawa TM 2013-152

11. DOCUMENT AVAILABILITY (Any limitations on further dissemination of the document, other than those imposed by security classification.)

Unlimited

12. DOCUMENT ANNOUNCEMENT (Any limitation to the bibliographic announcement of this document. This will normally correspond to the Document Availability (11). However, where further distribution (beyond the audience specified in (11) is possible, a wider announcement audience may be selected.))

Unlimited 13. ABSTRACT (A brief and factual summary of the document. It may also appear elsewhere in the body of the document itself. It is highly desirable that the abstract of classified documents be unclassified. Each paragraph of the abstract shall begin with an indication of the security classification of the information in the paragraph (unless the document itself is unclassified) represented as (S), (C), (R), or (U). It is not necessary to include here abstracts in both official languages unless the text is bilingual.) This document describes an initial assessment of the Rutter 100S6 marine radar system’s ability to perform a useful function as a limited air surveillance asset at a remote test site on Devon Island, overlooking Barrow Strait and Lancaster Sound. As part of the assessment, a set of trials was performed in the Ottawa-Gatineau area to measure the radar system’s ability to detect and track aircraft of opportunity in a land-based setting. The aircraft were of various types and sizes ranging from small general aviation aircraft (fixed and rotary wing) to large commercial jet airliners. Ground-truth of the aircraft classification, identification and course information was provided by a combination of visual means (i.e. naked eye, binoculars, and camera imagery) and, when available, Automatic Dependent Surveillance-Broadcast (ADS-B) reports. Only a few days of actual data collection was accomplished, which was performed intermittently over the period from 29 July to 19 September 2010. The outcome of the assessment was that this radar system has the potential to provide a useful, though limited, air surveillance role as long as the system constraints are respected. It was also determined that a more capable tracker would be needed if automatic surveillance of aircraft, with minimal analyst intervention, is required. The current alpha-beta tracker provided with radar system has difficulty initiating a track or maintaining track continuity on high speed (over 100 kph) manoeuvring targets, especially given their tendency for scintillation.

Ce document décrit une première évaluation de la capacité d'un système de radar de marine, le Rutter 100S6, pour remplir une fonction utile comme un atout pour la surveillance limitée des avions sur un site de test à distance sur l'île Devon, avec une vue sur les détroits de Barrow et de Lancaster. Dans le cadre de l'évaluation, une série d'essais a été réalisée dans la région d'Ottawa-Gatineau pour mesurer la capacité du système de radar pour détecter et suivre les avions d'occasion dans un cadre terrestre. Les avions étaient de différents types et tailles allant de petits avions de l'aviation générale (fixe et à voilure tournante) aux grands avions de ligne commerciaux. Rez-de-vérité de l'information pour la classification, l'identification et trajectoires de vol des aéronefs a été fourni par une combinaison de moyens visuels (à savoir l'œil nu, des jumelles, et l'imagerie de la caméra) et, lorsqu'il est disponible, la surveillance dépendante automatique en mode diffusion (ADS-B) rapports. Seulement un peu de jours de collecte de données réelles ont été accomplies; ils ont été réalisés par intermittence au cours de la période allant du 29 Juillet au 19 Septembre 2010. Le résultat de l'évaluation était que ce système radar a le potentiel de fournir un utile, bien que limité, le rôle de surveillance de l'air à condition que les contraintes du système sont respectées. Il a également été déterminé qu'un plus capable algorithme de poursuite serait nécessaire si la surveillance automatique des avions, avec un montant minimal de l'intervention par l'analyste, est nécessaire. Le courant traqueur alpha-bêta fourni avec le système radar a difficulté à initier une piste ou le maintien de la continuité de la piste pour les cibles de manœuvre à grande vitesse (plus de 100 km), en particulier en raison de leur tendance à scintiller. 14. KEYWORDS, DESCRIPTORS or IDENTIFIERS (Technically meaningful terms or short phrases that characterize a document and could be helpful in cataloguing the document.

100S6 Radar; navigation radar; air surveillance; Gatineau Executive Airport; Ottawa International Airport; ADS-B; Automatic Dependent Surveillance-Broadcast; propagation; ground clutter; Northern Watch; Technology Demonstration Program; Devon Island; SIESTA; Radar Cross Section; RCS; corner reflector