International Committee on GNSS-13 Focuses on PNT in High Earth Orbit and Beyond Since last reported in the November/December 2016 issue of Inside GNSS, signi cant progress has been made to extend the use of Global Navigation Satellite Systems (GNSS) for Positioning, Navigation, and Timing (PNT) in High Earth Orbit (HEO). This update describes the results of international e orts
that are enabling mission planners to con dently Artist’s rendering employ GNSS signals in HEO and how researchers are of Orion docked to the lunar-orbiting extending the use of GNSS out to lunar distances. Gateway. Image courtesy of NASA
tarting with nascent GPS space to existing ones, multi-GNSS signal Moving from Dream to Reality flight experiments in Low- availability in HEO is set to improve Within the National Aeronautics and SEarth Orbit (LEO) in the 1980s significantly. Users could soon Space Administration (NASA), the and 1990s, space-borne GPS is now employ four operational global con- Space Communications and Naviga- commonplace. Researchers continue stellations and two regional space- tion (SCaN) Program Office leads expanding GPS and GNSS use into— based navigation and augmenta- e orts in PNT development and policy. and beyond—the Space Service Vol- tion systems, respectively: the U.S. Numerous missions have been own in ume (SSV), which is the volume of GPS, Russia’s GLONASS, Europe’s the SSV, dating back to the rst ight space surrounding the Earth between Galileo, China’s BeiDou (BDS), experiments in 1997. NASA, through 3,000 kilometers and Geosynchronous Japan’s Quasi-Zenith Satellite Sys- SCaN and its predecessors, has sup- (GEO) altitudes. This has spawned tem (QZSS), and India’s Navigation ported high altitude GNSS develop- exciting space missions through the with Indian Constellation (NavIC). ment for more than 20 years. Others promise of improved PNT perfor- When combined, such “super-con- around the globe, including the Euro- mance, quick trajectory maneuver stellation” of 100+ GNSS satellites pean Space Agency (ESA), have also recovery, and enhanced on-board greatly improves signal coverage and performed similar ight experiments autonomy. However, there are limita- also increases the diversity of system to demonstrate feasibility of employ- tions that need to be addressed when architectures, frequencies and geom- ing GNSS at high altitudes. However, to using GNSS signals in HEO because etry. is, in turn, improves overall fully exploit all the GNSS signals, par- of their weak signal strength and the PNT performance and resiliency. ticularly given the signal-sparse envi- limited number of over-the-limb sig- With such new PNT capabilities ronment at high altitudes, the dream nals available from any one GNSS underway, mission planners are set- of ubiquitous PNT in HEO and beyond constellation. ting their sights well beyond the SSV, will only be realized if GNSS constel- With the recent development and even employing GNSS on upcoming lations are designed to be interoper- deployment of multiple GNSS con- missions such as the lunar-orbiting able for SSV use and their capabilities stellations, and ongoing upgrades Gateway. clearly documented and supported.
32 InsideGNSS JANUARY/FEBRUARY 2019 www.insidegnss.com Recently there has been a transition ous other specific improvements and JAMES J. MILLER from experimentation to operational new capabilities. It is due to this dem- NASA use of GNSS in high altitudes, includ- onstrated on-orbit performance that BENJAMIN W. ASHMAN ing the Magnetospheric Multiscale the GOES-R team has recommended NASA GODDARD SPACE FLIGHT CENTER Mission (MMS) and the Geostation- that future GEO satellites consider use FRANK H. BAUER ary Operational Environmental Satel- of GNSS for navigation to take advan- NASA lite (GOES-16). MMS is a NASA Solar tage of their available capabilities. ese DANIEL BLONSKI Terrestrial Probe launched in 2015 and examples highlight the importance in currently in a 1.2 Earth Radii (RE) x developing interoperable multi-GNSS EUROPEAN SPACE RESEARCH AND TECHNOLOGY CENTRE OF THE EUROPEAN SPACE AGENCY 25 RE orbit, which is more than 40% capabilities to further improve exist- of average lunar distance. MMS navi- ing GNSS-based capabilities available MADELEINE BRONSTEIN gation performance has significantly to users in HEO and beyond. For spe- OVERLOOK SYSTEMS TECHNOLOGIES, INC. exceeded mission requirements thanks ci c information on MMS and GOES-16 JENNIFER E. DONALDSON to the availability of GPS signals. GOES- navigation performance see 3, 4 and 5 NASA GODDARD SPACE FLIGHT CENTER 16 is the on-orbit designation of the rst under Additional Resources. WERNER ENDERLE of four NASA / National Oceanic and ESA’S EUROPEAN SPACE OPERATIONS CENTER Atmospheric Administration (NOAA) Multilateral Interoperability through A. J. ORIA GOES-R series of weather satellites International Engagement OVERLOOK SYSTEMS TECHNOLOGIES, INC. being launched between 2016 and 2024. In the early 2000s, bilateral meet- JOEL J. K. PARKER GOES-R represents a major leap forward ings were held to discuss GNSS signal NASA GODDARD SPACE FLIGHT CENTER in capability and technology, with GPS a interoperability. ese included, among O. SCOTT SANDS critical element in making this happen, others, bilateral meetings with the U.S. NASA, GLENN RESEARCH CENTER and improves weather forecasts to 5–7 and Russia on GPS/GLONASS interop- days, a full two days greater than the erability and the U.S.-European Union current capability, along with numer- on GPS/Galileo interoperability. ese www.insidegnss.com JANUARY/FEBRUARY 2019 InsideGNSS 33 SSV
and featured on television news cover- age. e booklet is available in printed form at the UN Headquarters in New York, U.S., and online (for link see 8 under Additional Resources).
ICG De nition of the Space Service Volume e multi-GNSS SSV has been de ned as the volume of space between 3,000-kilo- meter and 36,000-kilometer altitudes,
FIGURE 1 Left) SSV Information Booklet, (Right) Formal presentation at ICG-13 by ESA (Werner where terrestrial GNSS performance Enderle) and NASA (James. J. Miller) standards may not be applicable. GNSS service in the SSV is de ned by three key discussions ultimately led to a multi- a key role in the pursuit of interoper- parameters: pseudorange accuracy, min- lateral dialog in 2005 when the United able multi-GNSS capabilities to support imum received power, and signal avail- Nations (UN) formed the International space users. ability. Signal availability is the percent Committee on GNSS (ICG). To maximize the utility of GNSS of time that GNSS signals are available, e ICG is a forum to facilitate dis- for high-altitude space users, coordina- and is calculated both as the availability cussion on GNSS benefits to people tion among all GNSS service providers of one or four GNSS signals (depending around the world by promoting the use is taking place within two ICG work- on the metric being used). When there of GNSS and its integration into infra- ing groups: Working Group B (WG-B) are less than four signals available then structures (particularly in developing which supports “Enhancement of GNSS the employment of on-board naviga- countries) and encouraging compatibili- Performance, New Services and Capa- tion lters enable users to obtain PNT ty and interoperability among GNSS and bilities” and leads SSV development, updates even with as little as one GNSS regional navigation satellite systems. It coordination, and outreach; and Work- signal. A sub-metric is the Maximum was formally established in 2005 by the ing Group S (WG-S) which supports Outage Duration (MOD), defined as UN General Assembly 61/111 resolution, “Systems, Signals and Services” and the maximum duration when a space and the 1st ICG meeting was held in coordinates the underlying GNSS sig- user in a particular orbit cannot obtain 2006. Membership includes core GNSS nal interoperability. As part of the WG-B availability of at least one single signal and regional space-based navigation work plan, three years ago an SSV Team or at least four signals. e SSV covers system/augmentation provider nations, undertook a series of initiatives co- a large range of altitudes and the GNSS as well as nations with active programs chaired by ESA and NASA to continue performance degrades with increasing to implement or promote GNSS services the implementation of an interoperable altitude. erefore, to allow for a more and applications. e ICG also recog- GNSS SSV and provide recommenda- accurate re ection of these performance nizes associate members and observers tions to GNSS Service. Such efforts variations, the SSV is subdivided into from organizations and associations included an independent assessment of two distinct regions: that focus on GNSS services and appli- navigation performance in HEO using • Lower SSV for Medium Earth Orbits cations. Also, a GNSS Provider’s Forum, combined GNSS signals. Preliminary (MEO): Covers 3,000–8,000 km alti- which typically meets concurrently with results of these efforts were presented tude. It is characterized by reduced the ICG Plenary Meetings, was estab- in the November 13, 2016 Inside GNSS signal availability from a zenith- lished at the 2nd ICG meeting with the article “Navigating in Space.” Since then facing antenna alone, but increased aim to promote greater compatibility an authoritative publicly-available SSV availability if both a zenith and and interoperability among current and Booklet has been developed to detail nadir-facing antennas are used. future providers of the GNSS. Its mem- the multi-GNSS SSV, including coordi- • Upper SSV for GEO and HEO bers work to address key issues such as nated de nitions, bene ts and use cases, Orbits: Covers 8,000–36,000 km ensuring protection of GNSS spectrum constellation-speci c SSV signal perfor- altitude. It is characterized by signi - and matters related to orbital debris and mance data, and example technical data. cantly reduced signal received power orbit de-con iction. At the 3rd meeting The first edition of the SSV Booklet, and availability because most signals of the Provider’s Forum, held in 2008, titled “ e Interoperable Global Navi- travel across the limb of the Earth. it was agreed that at a minimum, all gation Satellite Systems Space Service The GNSS SSV is depicted in Fig- global GNSS signals and services must Volume”, was formally presented at the ure 2 along with the altitude ranges of be compatible. Since then both ICG and 13th ICG Plenary Meeting held Novem- the contributing GNSS constellations. Provider’s Forum meetings have played ber 4-9, 2018 in Xi’an, China (Figure 1) Most GNSS satellite vehicles are located
34 InsideGNSS JANUARY/FEBRUARY 2019 www.insidegnss.com Minimum Received Civilian Signal Power 0dBi RCP Reference antenna at o -boresight Band Constellation GEO (dBW) angle (°) L1/E1/B1 GPS -184 (C/A)1 23.5 -182.5 (C)2 GLONASS -179 26 Galileo -182.5 20.5 BDS -184.2 (MEO)3 25 -185.9 (I/G)4 19 QZSS -185.5 22 L5/L3/E5/B2 GPS -182 26 GLONASS -178 34 FIGURE 2 The GNSS Space Service Volume and its regions Galileo -182.5 (E5b) 22.5 -182.5 (E5a) 23.5 in MEO, and some are in geostationary and inclined geosyn- chronous orbits. BDS -182.8 (MEO) 28 -184.4 (I/G) 22 Estimated Performance of the Multi-GNSS SSV QZSS -180.7 24 e ICG WG-B SSV Team performed an international, col- NavIC -184.54 16 laborative simulation of the GNSS single-constellation and 1 L1 C/A signal 2 L1C signal 3 MEO satellites multi-constellation performance expectations. Global and 4 Inclined geosynchronous (I) and geostationary (G) satellites mission-speci c analyses were performed to capture overall performance characteristics and representative performance Table 1. Individual constellation SSV template data—received power for mission-speci c scenarios. e focus was on signal avail- ability, which serves as a proxy for navigation capability, and At least 1 signal 4 or more signals the L1 and L5 frequency bands. L2 frequency band perfor- Constella- Avail. MOD Avail. MOD mance is expected to be similar to that of the L5. Key methods Band tion (%)1 (min)2 (%)1 (min)2 and results are summarized here. For full details see the SSV L1/E1/ Global 78.5–94 48–111 0.6–7 * Booklet. e constellation-speci c SSV service characteristics B1 systems used in the analysis were taken from Table 1 and represent QZSS 0 * 0 * the baseline service documented by individual GNSS service providers. erefore, the results generated are intended to be Combined 99.9 33 89.8 117 L5/L3/ Global 93.4- conservative estimates. Actual on-orbit ight performance will 7–* 4.2–60.3 218–* di er from these estimates based on mission-speci c geometry, E5a/B2 systems 99.9 Regional receiver sensitivity, time-dependent service characteristics, and 1–30.5 * 0–1.5 * other factors. Also, only service provided by GNSS main-lobe systems signals is captured, where the boundary of this main-lobe is Combined 100 0 99.9 15 de ned as the reference o -boresight angle. 1 average across all grid locations 2 at worst-case grid location *no signal observed for the worst-case grid location for Global Availability Analysis full simulation duration Table 2 summarizes the global availability analysis results for Table 2. Summarized upper SSV global performance estimates (20 user spacecra at 36,000 kilometers altitude. e full set of dB-Hz C/N0 threshold) results for each individual constellation and for the combined multi-GNSS SSV are captured in Section 5.1 of the SSV Book- ing updates via a navigation lter. ese results show that the let. At a receiver threshold of 20 dB-Hz, four-signal availabil- abundance of signals available in an interoperable multi-GNSS ity at L1 for any individual constellation is very low, reaching SSV greatly reduces constraints for navigation compared to only 7%. When the GNSS constellations are used together then using an individual GNSS. four-signal availability reaches nearly 90%, thus allowing kine- matic solutions throughout the SSV with less than two hours Mission-Speci c Scenarios of outage. Furthermore, one-signal visibility is at 100% for L5, Mission-speci c performance was calculated by simulating and nearly so for L1, indicating continuous signal coverage for signal availability for a spacecra on a particular trajectory ensuring continuous or near continuous navigation and tim- within and beyond the SSV. e purpose was to provide “real- www.insidegnss.com JANUARY/FEBRUARY 2019 InsideGNSS 35 SSV
25
20 perform on-board real-time kinematic 15 orbit determination.
10 2. Highly-Elliptical Orbit Scenario
Visible Satellites 5 This scenario consisted of a mission in highly elliptical orbit with an apo- 0 0246810 12 14 16 18 20 22 gee altitude of 58,600 kilometers and Hours a perigee altitude of 500 kilometers. BDS GLONASS NavIC Combined The simulated user GNSS antennas Galileo GPS QZSS were con gured in both the nadir- and FIGURE 3 Best case example: L5 visibility for GEO at 60 degrees West over 24 hours. zenith- facing directions. As shown in Figure 4, a high-gain, narrow beam- width, nadir-pointing antenna ensures GNSS availability around apogee (above the GNSS constellations) while a low- gain, wide beamwidth zenith-pointing antenna provides visibility around perigee. For these results, only the best antenna (zenith or nadir) was used at a time. In a real-world case both anten- nas could be combined for greater avail- ability when operating below the GNSS satellites. FIGURE 4 Schematic of the HEO mission with nadir and zenith pointing antennas Figure 5 shows how GNSS signal availability varies over 1.5 orbital peri- world” estimates for specific mission the longitude of the user spacecraft. ods for the L1 band. For both L1 and types. ese provide prospective SSV Visibility is lowest near 180° longitude L5, 74% to 99% single-signal availabil- users with relevant results that dem- (western Paci c), and highest near 60° ity is provided by individual constella- onstrate the benefits and possibilities W (east of the U.S.). This indicates tions (even at apogee), but fully 100% o ered by an interoperable multi-GNSS that GEO space users positioned over is provided when all GNSS constella- SSV to specific mission classes. Three the western hemisphere are benefit- tions are used. Four-signal availability scenarios were considered: 1) geostation- ing from the spillover of signals from at apogee remains mainly below 20% ary orbit, 2) a highly-elliptic orbit, and 3) the regionally-focused constellations individually, but is nearly 100% when a lunar trajectory. Acquisition and track- positioned over Asia. Figure 3 shows used together, with maximum outages ing thresholds of the user receiver were the high case for the L5 band, in where of less than one hour. L5 availability is both set to 20 dB-Hz in all cases. Full this feature is clearly visible. Each of better compared to L1, with 100% avail- details on all scenarios are available in the MEO constellations contribute 1 ability and no outages because of wider Chapter 5 of the SSV Booklet. to 5 satellites to the overall visibility. beamwidths, slightly higher minimum But because of the GEO user location, received power values, and the addition 1. Geostationary Orbit Scenario BDS, with its inclined geosynchronous of NavIC. is scenario consisted of six geosta- and geostationary GNSS satellites, con- tionary satellites separated by 60° in tributes up to 9 visible satellites. With 3. Lunar Mission Scenario longitude. The results were intended all constellations combined, an aver- A lunar scenario was considered in order to be similar to those for the equiva- age of approximately 17 satellites are to explore the boundary of the GNSS lent points in the global analysis, but visible, more than double the average SSV beyond Earth orbit. A lunar trajec- are more representative because they contribution of any individual constel- tory from LEO to a lunar y-by with a were simulated using realistic user lation. Even in the worst GEO location return to Earth was simulated (Figure antenna patterns. Multi-GNSS visibil- (not shown in this particular gure), an 6). Only the outbound portion was used ity is highly variable depending on the average of approximately 9 are visible at in this analysis. As with the HEO case, user satellite location around the geo- any time, more than double the high- both the zenith-pointing and nadir- stationary belt. is occurs because vis- est individual contributor. In all cases, pointing user antennas were modelled, ibility of the inclined geosynchronous when using combined GNSS constella- with peak gains of 4.5 dBi and 9 dBi, and geostationary GNSS satellites of tions it is possible to continuously form respectively. e spacecra attitude was BDS, QZSS, and NavIC are fixed by an on-board navigation solution and kept nadir-pointing.
36 InsideGNSS JANUARY/FEBRUARY 2019 www.insidegnss.com 1e4 90 7
80 tance of approximately 30 RE, and zero 6 therea er. e bene t of the combined 70 multi-GNSS case is best seen above 10 5 RE, where signal availability is con- 60 sistently higher than any individual constellation, and o en nearly double. 4 50 Notably, combining constellations does not increase the altitude at which such 40 3 signals are available; rather, it increas- Visible Satellites 30 HEO altitude (km) es the number of signals available at a 2 given altitude. ese results show that 20 navigation with the combined multi- GNSS SSV is feasible for nearly half the 1 10 duration of a lunar outbound trajectory, well beyond the upper limit of the SSV, 0 0 0 and is possibly a solution for navigation Simulation time (minutes) for the outbound trans-lunar injection FIGURE 5 Visible GNSS satellites for HEO orbit over 1.5 orbital periods (L1 band) maneuver and return trajectory correc- tion maneuvers. ity, using the L5 band as an Figure 7 (Right) shows the simu-
example to capture the con- lated C/N0 received by the example tributions of all constella- spacecra for each individual GNSS tions. Availability is highly constellation and the entire trajectory dependent on distance from to lunar distance (60 RE). It shows Earth, and user receiver the reason for the availability drop- equipment assumptions for off near 30 RE shown in the Figure
the C/N0 tracking threshold 7 (Le ). e C/N0 of GNSS signals at and the user antenna gain. the user antenna drops below the 20 As the distance from Earth dB-Hz minimum threshold beyond increases the availability 30 RE. If a moderately more sensitive drops quickly and reaches receiver or higher-gain antenna were zero beyond 30 RE, which employed then signal availability FIGURE 6 Lunar trajectory phases – only the outbound seg- is approximately 50% of would be achievable up to the lunar ment was analysed the distance to the Moon. distance. A simple improvement in When using all constel- antenna gain has been proposed to Figure 7 (Left) shows the general lations combined the single-satellite support lunar vicinity missions such structure of the GNSS signal availabil- availability is nearly 100% to a dis- as Gateway.
30 45
25 40 35 20 30 15 (dBHz) 0 25
10 C/N Visible Satellites 20 5 15
0 10 0510 15 20 25 30 35 0 10 20 30 40 50 60 Distance (radius, RE) Distance (radius, RE)
FIGURE 7 (Left) L5 signal visibility by trajectory radial distance, to the limit of available signals at 30 RE (approx. 50% of lunar distance), (Right) Simulated C/N0 for entire lunar trajectory
www.insidegnss.com JANUARY/FEBRUARY 2019 InsideGNSS 37 SSV
Conclusions navigation and timing capabilities. e igation, and Control Performance Results for the Many emerging space missions are development of the multi-GNSS SSV is GOES-16 Spacecraft,” GNC 2017: 10th International ESA Conference on Guidance, Navigation & Control poised to bene t from precision naviga- truly an international cooperative e ort Systems, Salzburg, Austria, May 2017. tion and timing afforded through the by all GNSS providers. e contributions (4) Concha, M., Zanon, D., and Gillette, J., “Perfor- employment of GNSS signals in the SSV. of the experts that have developed this mance Characterization of GOES-R On-Orbit GPS Currently, several operational missions technology will enable untold space mis- Based Navigation Solution,” AAS Guidance and Con- already use single constellation GNSS in sions that will extend humanity’s reach trol Conference 2017, Feb 2017, Breckenridge, CO, and above the SSV to improve their vehi- for the stars, its understanding of the AAS Paper 17-138. cle navigation performance, most nota- planet Earth, and its critical protection (5) Winkler, A., Ramsey, G., Frey, C., Chapel, J., Chu, bly the GOES weather satellites at GEO of people and property. D., Freesland, D., Krimchansky, A., Concha, M., “GPS Receiver On-Orbit Performance for the GOES-R and the MMS four-spacecra formation The UN SSV Booklet presented Spacecraft,” GNC 2017: 10th International ESA Con- ying mission at altitudes up to 150,000 at ICG-13 represents a key milestone ference on Guidance, Navigation & Control Systems, kilometers, which is more than 40% of towards the development of an interop- Salzburg, Austria, May 2017. the distance between the Earth and the erable multi-GNSS SSV, and will be (6) Enderle, Werner, Gini, Francesco, Boomkamp, Moon. Future spacecra users at these updated through future editions as new Henno, Parker, Joel J.K., Ashman, Benjamin W., altitudes and beyond can bene t from information and analyses become avail- Welch, Bryan W., Koch, Mick, Sands, O. Scott, “Space User Visibility Benefits of the Multi-GNSS Space the improved performance a orded by able. Service Volume: An Internationally-Coordinated, an interoperable multi-GNSS capability. Global and Mission-Speci c Analysis,” Proceedings e multi-GNSS SSV promises to be Acknowledgements of the 31st International Technical Meeting of The transformative in the operation of high- e authors express their sincere thanks Satellite Division of the Institute of Navigation (ION altitude spacecraft when compared to to everyone that has supported activities GNSS+ 2018), Miami, Florida, September 2018, pp. 1191-1207. the use of a single constellation alone. leading towards the development GNSS Multi-GNSS bene ts include increased capabilities to support space users in (7) Parker, Joel J. K., Bauer, Frank H., Ashman, Ben- jamin W., Miller, James J., Enderle, Werner, Blonski, signal availability, increased geomet- HEO and beyond. Special recognition Daniel, “Development of an Interoperable GNSS ric diversity, increased responsive- also goes to the GNSS and regional Space Service Volume,” Proceedings of the 31st Inter- ness, less reliance on expensive clocks, navigation system providers includ- national Technical Meeting of The Satellite Division of vehicle autonomy enhancements due to ing the: U.S. Air Force GPS Director- the Institute of Navigation (ION GNSS+ 2018), Miami, reduced signal outages, and increased ate, Europe’s Galileo Team, Russia’s Florida, September 2018, pp. 1246-1256. resiliency due to the diversity of signals GLONASS team, China’s BeiDou team, (8) “The Interoperable Global Navigation Satellite Systems Space Service Volume,” United Nations and constellations used. ese bene ts Japan’s QZSS team, and India’s NavIC Office for Outer Space Affairs, November 30, are truly enabling for classes of emerg- team. Also instrumental in the multi- 2018. http://www.unoosa.org/res/oosadoc/data/ ing advanced users, including ultra-sta- GNSS SSV development were the lead- documents/2018/stspace/stspace75_0_html/ ble remote sensing from geostationary ers and international delegates from st_space_75E.pdf orbit, agile and responsive formation y- the UN International Committee on ing, more e cient utilization of valuable GNSS, including the ICG Secretariat Author slots in the GEO belt and lunar missions. Ms. Sharafat Gadimova and the relevant James J. Miller is Deputy Director e UN ICG WG-B has worked in ICG working groups. In particular, the of Policy & Strategic Communica- a collaborative fashion to establish an WG-B leads and SSV subject matter tions within the Space Commu- interoperable multi-GNSS SSV where all experts, as acknowledged in Annex F nications and Navigation Pro- gram at the NASA Headquarters. GNSS constellations and regional navi- of the SSV booklet, that are transform- His duties include advising NASA gation systems can be utilized together ing the multi-GNSS SSV from vision to leadership on Positioning, Navi- to improve mission performance. is reality. gation, and Timing (PNT) policy e ort has resulted in an internationally- and technology, and is also the Executive Director agreed definition of the multi-GNSS Additional Resources of the National Space-based PNT Advisory Board. SSV and captures the SSV performance (1) Miller, James J., Bauer, Frank H., Oria, A.J., Pace, Co-Authors / Contributors contributions of each individual GNSS Scott, Parker, Joel J.K., “Achieving GNSS Compatibili- Benjamin W. Ashman is an Aero- ty and Interoperability to Support Space Users,” Pro- space Engineer at the NASA God- constellation. In addition, international- ceedings of the 29th International Technical Meeting ly validated simulations show the perfor- dard Space Flight Center, where he of The Satellite Division of the Institute of Navigation supports numerous space commu- mance bene ts of the combined systems (ION GNSS+ 2016), Portland, Oregon, September nication and navigation efforts, for several reference mission scenarios. 2016, pp. 3622-3634. most recently as part of the OSIRIS- This information is documented in a (2) “Navigating in Space,” Inside GNSS, November 13, REx navigation team. His research has primarily publicly-available UN published book- 2016. http://insidegnss.com/navigating-in-space/ been focused on space applications of GPS since let that will help high altitude space (3) Chapel, J., Stancli e, D., Bevacqua, T., Winkler, S., starting at the agency in 2015. mission designers employ multi-GNSS Clapp, B., Rood, T., Freesland, D., Reth, A., Early, D., Walsh, T., Krimchansky, A., “In-Flight Guidance, Nav-
38 InsideGNSS JANUARY/FEBRUARY 2019 www.insidegnss.com Frank H. Bauer supports NASA with Jennifer E. Donaldson is an Aero- port of PNT activities at the Space Communications expertise in spacecraft systems space Engineer in the Components and Navigation (SCaN) Program O ce. engineering, Guidance Navigation and Hardware Systems Branch at Joel J. K. Parker is the Positioning, and Control (GN&C), space-borne NASA Goddard Space Flight Center, Navigation, and Timing (PNT) Policy GNSS, and spacecraft formation y- where she is involved in numerous lead at NASA Goddard Space Flight ing. He previously served as NASA’s projects related to GPS, GNSS, and Center, where he develops and pro- Chief Engineer for Human Space ight Exploration spacecraft navigation. motes civil space use of GNSS on beyond low Earth Orbit and as Chief of the GN&C Werner Enderle is the Head of the behalf of NASA Space Communica- Division at NASA’s Goddard Space Flight Center. Navigation Support O ce at ESA’s tions and Navigation (SCaN). He has worked as an Daniel Blonski is Navigation Sys- European Space Operations Center Aerospace Engineer at NASA since 2010. tem Performance Engineer at the (ESOC) in Darmstadt, Germany. Pre- O. Scott Sands has been a Com- European Space Research and viously, he worked at the European munications System Analyst at Technology Centre of the European GNSS Authority (GSA) as the Head NASA, Glenn Research Center since Space Agency in Noordwijk, Neth- of System Evolutions for Galileo and EGNOS and he 2000 where he develops space erlands, where he is contributing to also worked for the European Commission in the navigation, sensing and communi- the development of the European Navigation Sys- Galileo Unit. Since more than 20 years, he is cations systems. Scott currently tems as a member of the ESA Directorate of Navi- involved in activities related to the use of GPS/ leads Position Navigation and Timing Policy related gation. GNSS for space applications. He holds a doctoral activities at GRC in support of the NASA’s Space Madeleine Bronstein is a Systems degree in aerospace engineering from the Techni- Communications and Navigation (SCaN) Program Analyst at Overlook Systems Tech- cal University of Berlin, Germany. O ce. nologies, Inc. supporting the NASA A. J. Oria is an Aerospace Engineer Space Communications and Navi- at Overlook Systems Technologies, gation (SCaN) Program O ce. Ms. Inc. and Program Manager for NASA Bronstein is the Secretariat of the Support. Dr. Oria joined Overlook Interagency Operations Advisory Group (IOAG) and in 1998 and since 2003 has been supports outreach for navigation policy and space providing GPS, navigation policy, communications activities. and engineering subject matter expertise in sup-
ACCURATE, RELIABLE & ROBUST GNSS MORE COMPACT THAN EVER
Your positioning cornerstone
www.insidegnss.com JANUARY/FEBRUARY 2019 InsideGNSS 39