(19) & (11) EP 2 202 490 A2 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 30.06.2010 Bulletin 2010/26 G01C 23/00 (2006.01) (21) Application number: 09178242.5 (22) Date of filing: 07.12.2009 (84) Designated Contracting States: (72) Inventors: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR •Dwyer,David HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL Morristown, NJ 07962-2245 (US) PT RO SE SI SK SM TR • Gilliland, Jr., William Ray Morristown, NJ 07962-2245 (US) (30) Priority: 23.12.2008 US 342534 (74) Representative: Buckley, Guy Julian (71) Applicant: Honeywell International Inc. Patent Outsourcing Limited Morristown, NJ 07962 (US) 1 King Street Bakewell Derbyshire DE45 1DZ (GB) (54) Systems and methods for displaying heading-based leg symbology (57) An aircraft display system includes a processor coupled to the processor. The horizontal situation indi- configured to receive a heading-based leg and to gener- cator receives the display signals from the processor and ate display signals based on the heading-based leg; and displaying symbology representing the heading-based a display device including a horizontal situation indicator leg. EP 2 202 490 A2 Printed by Jouve, 75001 PARIS (FR) 1 EP 2 202 490 A2 2 Description present invention will become apparent from the subse- quent detailed description of the invention and the ap- TECHNICAL FIELD pended claims, taken in conjunction with the accompa- nying drawings and this background of the invention [0001] The present invention generally relates to air- 5 craft display systems and methods, and more particularly BRIEF SUMMARY relates to systems and methods for displaying symbology for heading-based legs of flight plans. [0007] In accordance with an exemplary embodiment, an aircraft display system includes a processor config- BACKGROUND 10 ured to receive a heading- based leg and to generate dis- play signals based on the heading-based leg; and a dis- [0002] An important facet of aviation safety is the pilot’s play device including a horizontal situation indicator cou- situational awareness of the status of the aircraft, includ- pled to the processor. The horizontal situation indicator ing its position, velocity, and external factors such as wind receives the display signals from the processor and dis- direction and terrain. Toward this end, advances in hu- 15 playing symbology representing the heading-based leg. man factors research have led to dramatic improvements [0008] In accordance with another exemplary embod- inthe display of information to the pilot. Further, advances iment, a method for displaying symbology for a heading- in visual display technology, such as high quality flat dis- based leg includes receiving a signal associated with a play panels, have enabled the pilot to be presented with heading-based leg; and displaying symbology on a hor- information in a visual format that is not possible with 20 izontal situation indicator associated with the heading- traditional dials and gauges. based flight leg. [0003] During operation, the aircraft’s heading corre- [0009] In accordance with yet another exemplary em- sponds to the horizontal component (perpendicular to bodiment, a horizontal situation indicator for an aircraft the local gravity vector) of the direction in which the air- display system includes a compass card configured to craft is pointing. If the aircraft is flying in wind that has a 25 display a current heading of the aircraft based on signals velocity component at an angle to the heading, the air- from a heading source; and symbology on the compass craft’s direction of flight will change according to a drift card indicating a desired heading based on a heading- angle that is proportional to the speed of the aircraft and based leg. the speed of the perpendicular component of the wind velocity. The resulting horizontal direction of the aircraft’s 30 BRIEF DESCRIPTION OF THE DRAWINGS motion along the ground is referred to as ground track (hereinafter "track"). [0010] The present invention will hereinafter be de- [0004] One of the primary flight displays the pilot uses scribed in conjunction with the following drawing figures, on the flight deck to determine whether the aircraft is on whereinlike numerals denotelike elements, and wherein: the planned flight path is a horizontal situation indicator 35 [0011] FIG. 1 is a functional block diagram of a system (HSI). One function of the HSI is to provide a visualization for displaying symbology associated with heading-based of the position of the aircraft with respect to a VOR (VHF flight plan paths in accordance with an exemplary em- OmnidirectionalRange) radial signal broadcast by a VOR bodiment; station. The HSI also has a compass card that displays [0012] FIG. 2 is a horizontal situation indicator (HSI) the direction of the aircraft relative to the earth’s magnetic 40 of the system of FIG. 1 in accordance with an exemplary field. During flight, the pilot uses the HSI to verify the embodiment; and location of the aircraft against the flight plan. [0013] FIG. 3 is an HSI of the system of FIG. 1 in ac- [0005] Most flight plan path procedures are based on cordance with another exemplary embodiment; ground track, and the flight management system of the [0014] FIG. 4 is an HSI of the system of FIG. 1 in ac- aircraft provides navigation information to the HSI that is 45 cordance with another exemplary embodiment; and based on ground track. As such, the information provided [0015] FIG. 5 is a method for displaying symbology for to the HSI by the FMS is based on a track-based flight heading-based legs in accordance with an exemplary plan. However, at times, air traffic controllers direct the embodiment. aircraft to fly a heading-based flight plan path. In these situations,pilots must typically mentally convert the track- 50 DETAILED DESCRIPTION based indications provided by the HSI into the designated heading-based path, and manually fly the heading- based [0016] The following detailed description is merely ex- flight plan path. emplary in nature and is not intended to limit the invention [0006] Accordingly, it is desirable to provide systems or the application and uses of the invention. Furthermore, and methods that display symbology for heading-based 55 there is no intention to be bound by any theory presented legs of a flight plan. In addition, it is desirable to provide in the preceding background or the following detailed de- an HSI with symbology for heading- based legs. Further- scription. more, other desirable features and characteristics of the [0017] Broadly, exemplary embodiments discussed 2 3 EP 2 202 490 A2 4 herein provide systems and methods for displaying sym- with the processor 120, or it may be remotely located, bology associated with heading-based legs. More spe- whereby the processor 120 accesses the memory 125 cifically, exemplary embodiments include a horizontal sit- via a network connection. uation indicator (HSI) with symbology indicating the [0021] The flight management system 130 is coupled heading-based leg. The symbology can include an arrow 5 to processor 120, and can provide navigation data asso- pointing in the direction of the designated heading- based ciated with the aircraft’s current position and velocity and leg; a text-based indicator of the designated heading- flight direction (e.g., heading, course, track, etc.) to the based leg; and/or a heading indicator showing the des- processor 120. The navigation data provided to the proc- ignated heading-based leg. essor 120 can also include information about the air- [0018] FIG. 1 is a system 100 for displaying symbology 10 craft’s airspeed, altitude, pitch, and other important flight for heading-based flight plan paths in accordance with information. In exemplary embodiments, the flight man- an exemplary embodiment. The system 100 includes a agement system 130 can include any suitable position display device 110, which includes a horizontal situation and direction determination devices that are capable of indicator (HSI) 200, discussed in greater detail below; a providing theprocessing unit 120 with at least an aircraft’s processor 120 having a memory 125; and a flight man- 15 current position (e.g., in latitudinal and longitudinal form), agement system 130, which may include a Global Posi- the real-time direction (heading, course, track, etc.) of tioning System (GPS) 132 and an Inertial Reference Sys- the aircraft in its flight path, the waypoints along the flight tem (IRS) 134. The flight management system 130 may path, and other important flight information (e.g., pitch, also receive data from sources such as air data, AHRS, airspeed, altitude, attitude, etc.).- In general, the flight VORs, DMEs, TACANs, MLS, ILS, LORAN- C, and ADF. 20 management system 130 is capable of providing real- Althoughthe system 100 appears in FIG. 1 to be arranged time track and heading information. The flight manage- as an integrated system, the system 100 is not so limited ment system 130 further provides track-based or head- and can also include an arrangement whereby one or ing-based flight plan paths, including turn direction, head- more of the display device 110, processor 120, and flight ing to be flown, deviation from heading, allowed devia- management system 130 are separate components or 25 tion, termination point of heading leg, and auto/manual subcomponents of another system located either on- control for turning the aircraft. board or external to the aircraft. Moreover, exemplary [0022] In general, the flight management system 130 embodiments of the system 100 can also be utilized in provides a flight plan made up of one or more legs. In spacecraft, ships, submarines, fixed wing and rotor air- exemplary embodiments, the flight management system craft, as well as other types of vehicles that are affected 30 130 provides heading- based legs, as required or desired by wind or other forces that may cause the vehicle to by the pilot, ground control, or another party or system.