Method and system for operating an aircraft

Abstract

An apparatus and method for operating a communication system for a vehicle includes a directional communication receiver configured to output a signal related to beam tracking strength, an inertial reference module configured to receive the beam tracking strength and provide a heading observation based on the beam tracking strength, and at least one indicator communicatively coupled to the inertial reference module to provide an indication related to a heading of the vehicle.

Description

Technical Field

[0001] The present disclosure relates generally to communication systems and methods for operating a vehicle and, more particularly, to a system for determining satellite signal strength related to beam tracking strength. Background Art

[0002] Aircraft utilize satellite inertial navigation systems to determine information used during flight. The use of the term "satellite" is meant to include not only all kinds of satellites orbiting the Earth, but also other forms of platforms that can be used cooperatively to determine the position and attitude of the platform carrying the inertial navigation system.

[0003] The Global Positioning System (GPS) is a current example of an Earth-orbiting satellite navigation system consisting of 24 globally distributed, synchronized atomic clock satellites. A user who knows the position, velocity, and clock errors of the satellites can calculate their own position, velocity, and clock errors from the measured pseudoranges and delta ranges. The use of three spatially distributed antennas on the platform allows accurate determination of pitch, roll, and heading using only GPS signals. However, if the platform is a highly maneuverable vehicle, it is necessary to integrate the platform GPS equipment with an inertial navigation unit. GPS compensates for the drift of the inertial navigation system, and when platform maneuvers or other events render the GPS temporarily inoperable, the inertial navigation system (INS) continues to operate until GPS becomes operational again. Summary of the invention

[0004] In one aspect, the present disclosure relates to a method of operating an aircraft, the method comprising causing the aircraft to fly along a heading, receiving a directional signal from a signal source at an antenna on the aircraft to define a received signal; determining a signal strength of the received signal; defining a first heading observation value based on the signal strength; and indicating at least one of a heading change or a quality factor based on the first heading observation value.

[0005] In another aspect, the present disclosure relates to a communication system for a vehicle, comprising a directional communication receiver configured to output a signal related to a beam tracking strength; an inertial reference module configured to receive the beam tracking strength and provide a heading observation based on the beam tracking strength, the inertial reference module configured to determine a heading change indicative of a quality of the vehicle's heading based at least on the heading observation and provide an output related to the heading change, the inertial reference module configured to provide the heading observation and output related to the heading change in an environment where radio navigation aids are denied; and at least one indicator communicatively coupled to the inertial reference module to provide an indication related to the validity of the heading of the vehicle based on the heading change. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In the attached picture:

[0007] Figure 1 is a schematic diagram of an aircraft having multiple aircraft systems according to aspects described herein.

[0008] Figure 2 It is available for use with aircraft. Figure 1 A block diagram of at least one of the aircraft systems.

[0009] Figure 3 is a flow chart of a method of operating an aircraft according to one aspect of the disclosure.

[0010] Figure 4 is a flow chart of another method of operating an aircraft according to another aspect of the present disclosure.

[0011] Figure 5 is a flow chart of yet another method of operating an aircraft according to another aspect of the present disclosure. DETAILED DESCRIPTION

[0012] Aspects of the present disclosure relate to a satellite communication (SATCOM) system that monitors signal tracking strength to determine whether they are received from or broadcast to appropriate satellites in space. As a non-limiting example, this determination helps in the accuracy of operations including aircraft flight.

[0013] Heading observations are traditionally obtained from radio navigation aids such as a Global Positioning System (GPS) receiver or a Global Navigation Satellite System (GNSS) receiver. These require the system to receive these external radio signals. Traditional radio navigation aids such as GPS are easily jammed. Radio interference or operation in a GPS denied environment prevents the inertial system from obtaining heading observations. Without external observations, the inertial system will drift and the ability to point to a solution or accurately determine the vehicle's heading and provide a reference for the directional system will be reduced. The tracking strength of the SATCOM signal does not rely on traditional land-based radio signals or weak GPS satellite signals that can be jammed.

[0014] The SATCOM connection itself is not subject to GPS interference. If the vehicle's inertial pointing solution is degraded due to a lack of GPS heading observations, the vehicle may not be able to maintain an accurate heading due to drift in the inertial sensors. Aspects of the present disclosure provide heading observations independent of GPS to correct for inertial drift or provide an indication of the amount of drift and maintain the pointing solution for a longer period of time.

[0015] It is understood that the signal strength degrades as the antenna pointing solution drifts. An inertial reference unit may be responsible for providing this antenna pointing solution, which may be a combination of heading, pitch, roll, rate, position, and timing data. Feeding the signal tracking strength back to the inertial reference unit may cause it to form a heading observation. The heading observation indicates the quality of the heading solution provided by the inertial reference unit. The heading observation may be used in a multi-state Kalman filter to correct for the drift of the inertial sensor and maintain a valid heading for a longer period of time.

[0016] It will therefore be understood that Figure 1 The aircraft 10 shown in the figure is an environment that can be provided for implementing the communication and inertial navigation system (INS) functions described herein. More specifically, for this embodiment, the functionality will be implemented on the aircraft 10. The aircraft 10 may include one or more propulsion engines 12 coupled to a fuselage 14. A cockpit 16 may be positioned in the fuselage 14 and a wing assembly 18 may extend outwardly from the fuselage 14. In addition, a set of aircraft systems 20 that enable the normal operation of the aircraft 10 may include one or more controllers, computers or controller modules 22, a communication system with a communication link 24, and an antenna 26. The antenna 26 can be positioned to receive directional signals, specifically, as a non-limiting example, signals associated with a SATCOM system.

[0017] It should be understood that a "group" may include any number of aircraft systems, including only one aircraft system. Although commercial aircraft have been shown, it is contemplated that aspects of the present disclosure may be used in any type of aircraft, such as, but not limited to, fixed-wing, rotary-wing, rockets, personal aircraft, unmanned aerial systems (UAS), and military aircraft.

[0018] In addition, as used herein, a "controller" or "controller module" may include a component that is constructed or adapted to provide instructions, control, operation, or any form of communication to an operable component to affect its operation. The controller module may include any known processor, microcontroller, or logic device, including, but not limited to: a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a full authority digital engine control (FADEC), a proportional controller (P), a proportional integral controller (PI), a proportional differential controller (PD), a proportional integral differential controller (PID controller), a hardware accelerated logic controller (e.g., for encoding, decoding, code conversion, etc.), the like, or a combination thereof. Non-limiting examples of controller modules may be constructed or adapted to run, operate, or otherwise execute program code to achieve an operation or functional result, including performing various methods, functions, processing tasks, calculations, comparisons, sensing or measurement values, etc., to achieve or realize the technical operations or operations described herein. The operation or functional result may be based on one or more inputs, stored data values, sensing or measurement values, indications of correctness or error, etc. Although "program code" is described, non-limiting examples of operable or executable instruction sets may include routines, programs, objects, components, data structures, algorithms, etc., which have the technical effect of performing specific tasks or realizing specific abstract data types. In another non-limiting example, the controller module may also include a data storage component accessible by the processor, including a memory, whether transient, volatile or non-transient or non-volatile memory. Other non-limiting examples of memory may include random access memory (RAM), read-only memory (ROM), flash memory or one or more different types of portable electronic memory, such as optical disks, DVDs, CD-ROMs, flash drives, universal serial bus (USB) drives, etc., or any suitable combination of these types of memory. In one example, the program code may be stored in a memory in a machine-readable format accessible to the processor. In addition, as described herein, the memory may store various data, data types, sensed or measured data values, inputs, generated or processed data, etc., which may be accessed by the processor when providing instructions, controls or operations to affect functions or operable results.

[0019] Additionally, as used herein, an element that is "electrically connected," "electrically coupled," or "in signal communication" may include electrical transmissions or signals that are sent, received, or transmitted to or from such connected or coupled elements. Furthermore, such electrical connections or couplings may include wired or wireless connections, or combinations thereof.

[0020] Furthermore, as used herein, although a sensor may be described as "sensing" or "measuring" a corresponding value, sensing or measuring may include determining a value indicative of or related to the corresponding value, rather than directly sensing or measuring the value itself. The sensed or measured value may be further provided to an additional component. For example, the value may be provided to a controller module or processor as defined above, and the controller module or processor may perform processing on the value to determine a representative value or an electrical characteristic representing the value.

[0021] All directional references (e.g., radial, axial, proximal, distal, above, below, upward, downward, left, right, lateral, front, rear, upper, lower, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, backward, etc.) are used only for identification purposes to help the reader understand the present disclosure and should not be interpreted as limiting, especially the use of position, direction or aspect of the present invention. The disclosure described herein. Unless otherwise specified, connection references (e.g., attachment, connection, connection and engagement) will be interpreted broadly and may include intermediate members between sets of elements and relative movement between elements. As such, connection references do not necessarily infer that two elements are directly connected and in a fixed relationship to each other. The exemplary drawings are for illustrative purposes only, and the sizes, positions, orders and relative sizes reflected in the attached drawings may vary.

[0022] The set of aircraft systems 20 may reside within the cockpit 16, within an electronics and equipment bay (not shown), or at other locations within the aircraft 10, including where they may be associated with the engines 12. Such aircraft systems 20 may include, but are not limited to, electrical systems, oxygen systems, hydraulic or pneumatic systems, fuel systems, propulsion systems, flight controls, audio / visual systems, integrated vehicle health management (IVHM) systems, and systems associated with the mechanical structure of the aircraft 10.

[0023] The controller module 22, which may be an FMS or one or more other systems, may be operably coupled to a set of aircraft systems 20 and may assist in operating the set of aircraft systems 20 and may receive information from the set of aircraft systems 20 and the communication link 24. The controller module 22 may automate the tasks of piloting the aircraft 10 and tracking of the flight plan, among other things. The controller module 22 may also interface with other controllers or computers of the aircraft 10. It should be understood that the controller module 22 may be a larger system than that shown and that the drawings are for illustration purposes only.

[0024] The controller module 22 may include a memory 28, which may include random access memory (RAM), read-only memory (ROM), flash memory, or one or more different types of portable electronic memory, such as optical disks, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The controller module 22 may include one or more processors 30 that may run any suitable program. It should be understood that the controller module 22 may include or be associated with any suitable number of separate microprocessors, power supplies, storage devices, interface cards, autoflight systems, flight management computers, and other standard components, and that the controller module 22 may include or be used in conjunction with any number of software programs (e.g., flight management programs) or instructions designed to perform the various methods, process tasks, calculations, and control / display functions necessary for the operation of the aircraft 10.

[0025] The communication link 24 and antenna 26 may be communicatively coupled to the aircraft's controller module 22 or other processor to pass information back and forth between the aircraft 10. It is contemplated that the communication link 24 and antenna 26 may be wireless and may be any communication mechanism capable of wirelessly linking with other systems and devices, and may include, but is not limited to, satellite uplinks, SATCOM Internet, VHF data links (VDL), ACARS networks, aeronautical telecommunications networks (ATNs), automatic dependent surveillance broadcast (ADS-B), wireless fidelity (WiFi), WiMax, 3G wireless signals, code division multiple access (CDMA) wireless signals, global system for mobile communications (GSM), 4G wireless signals, long term evolution (LTE) signals, or any combination thereof. It should also be understood that the specific type or mode of wireless communication is not critical to aspects of the present disclosure, and later developed wireless networks are certainly contemplated to be within the scope of aspects of the present disclosure. In addition, the communication link 24 and antenna 26 may be communicatively coupled to the controller module 22 via a wired link without changing the scope of aspects of the present disclosure. Although only one communication link 24 and antenna 26 are shown, it is contemplated that the aircraft 10 may have multiple communication links and antennas communicatively coupled to the controller module 22. Such multiple communication links and antennas may provide the aircraft 10 with the ability to communicate information to and from the aircraft 10 in a variety of ways.

[0026] As shown, the controller module 22 can communicate with a designated ground station 32 via a communication link 24. The ground station 32 can be any type of communication ground station 32, such as one operated by an air navigation service provider (ANSP) and / or air traffic control (ATC). The controller module 22 can request and receive information from the designated ground station 32, or the designated ground station 32 can send a transmission to the aircraft 10.

[0027] The controller module 22 may also communicate with a satellite 34 via an antenna 26. The satellite 34 may be any type of satellite, including but not limited to a geostationary satellite. The controller module 22 may request and receive information from the satellite 34, or the satellite 34 may send a transmission to the aircraft 10. Since the satellites in the SATCOM system are geosynchronous, the SATCOM connection itself is not subject to GPS interference. When the indication solution drifts outside the angular beam width (α), the signal strength decreases. Therefore, it is best to keep the indication solution within the angular beam width (α). Signals associated with a heading 36 for a planned navigation route may be transmitted to the computer from a designated ground station 32 and / or from a satellite 34 to the computer.

[0028] As from Figure 1 Call Out II Figure 2 As more clearly shown in FIG. 1 , the controller module 22 may communicate with a set of aircraft systems 20, specifically including an inertial navigation system (INS) 40. The INS 40 may include at least one receiver 42 for receiving a positioning signal 44 indicative of at least one of position (x), velocity (v), or timing (t) information associated with the aircraft 10. The receiver 42 may include, but is not limited to, a GNSS receiver or a GPS receiver, or may include both a GNSS and a GPS receiver. It is contemplated that other known satellites may communicate with the receiver 42 to transmit the positioning signal 44, such as but not limited to Galileo satellites, COMPASS MEO satellites, GPS satellites, GLONASS satellites, NAVIC satellites, QZSS satellites, or BeiDou-2 satellites.

[0029] The INS 40 may also include an inertial reference module 46. The inertial reference module 46 may include a set of inertial sensors 48 that may track one or a combination of inertial signals 50 that indicate pitch (θ), roll (θ), and and at least one of a yaw (ψ) rate. Each inertial sensor 48 is configured to provide measurement information to an inertial reference module 46. The measurement information may be filtered by a multi-state Kalman filter 51 to correct for drift of the inertial sensors.

[0030] The inertial reference module 46 may also include a lookup table 52 for storing predetermined heading values ​​54. The predetermined heading values ​​54 may be a set of values ​​stored in the lookup table 52 that are associated with the heading 36 of the aircraft 10. A navigation filter 56 may be provided in the INS 40 for receiving the positioning signal 44, the inertial signal 50, and the predetermined heading values ​​54.

[0031] The set of aircraft systems 20 may also include a SATCOM system 60 having at least one receiver / transmitter 62 for receiving a directional signal 63 in the form of a directional satellite beam signal 64 from the satellite 34. The receiver / transmitter 62 may be in direct communication with the antenna 26. It is also contemplated that the receiver / transmitter 62 may be the antenna 26. A received signal 66 associated with the directional satellite beam signal 64 may be received by the INS 40 and may be received at the navigation filter 56 as a first heading observation 68a in the form of a signal strength 70. A second heading observation 68b, as a non-limiting example, at least one positioning signal 44 may also be received at the navigation filter 56.

[0032] The first heading observation 68a may be compared to the predetermined heading value 54 to determine the heading change 72. The accuracy of the heading 36 may be indicated by a figure of merit (FOM) 74, which in turn may indicate an amount of heading error expected by the navigation filter 56 and associated with the heading change 72. In other words, the FOM 74 may be a numerical expression representing the performance or efficiency of the navigation filter 56. It is also contemplated that the first heading observation 68a, along with the second heading observation 68b, may be compared to the predetermined heading value 54 to determine the heading change 72. Furthermore, determining the heading change 72 may also include comparing the predetermined heading value 54 to the inertial signal 50. The heading change 72 may be relayed to the antenna 26. It should be appreciated that the heading change 72 may be a figure of merit based on the first heading observation 68a. It should be further appreciated that the heading change 72 may be a set of factors based on the first heading observation 68 a , the second heading observation 68 b , and the inertial signal 50 , when compared to the predetermined heading value 54 .

[0033] The heading change 72 may be received at a controller or beam steering module 76 for controlling the azimuth and elevation of the antenna 26. In this regard, the antenna 26 may be adjusted to remain within a beam width (α) associated with precise pointing of the strongest satellite 34 to the system 20 for connection.

[0034] A cockpit display unit 78 located in the cockpit 16 may be operably coupled to the aircraft systems 20, including the INS 40 and the SATCOM system 60. Information related to the aircraft systems 20 may be relayed to the pilot via the flight display. At least one indicator 90, as a non-limiting example, a numerical value associated with the heading change 72 or the FOM 74, may provide an indication related to the validity of the heading of the aircraft 10 based on the heading change 72. The at least one indicator 90 may be displayed on the flight display module 80. It is also contemplated that the indicator 90 may be re-evaluated in the navigation filter 56 and / or communicated directly to the antenna 26 as an adjustment signal 92. The adjustment signal 92 may cause movement of the antenna 26 to remain within the beam width (α).

[0035] The cockpit display unit 78 may also be connected to other controllers (not shown) of the aircraft 10 and may include a memory and a processing unit that may run any suitable program to display information to the pilot of the aircraft. The cockpit display unit 78 may include one or more graphics processors dedicated to rendering high-resolution displays. The cockpit display unit 78 may also receive input from one or more other additional sensors (not shown) that may provide various information to the cockpit display unit 78 to assist in the operation of the aircraft 10.

[0036] This article will describe the method steps that can be implemented by a program product including machine executable instructions (e.g., program code), for example, a program code implemented in the form of a program module executed by a machine in a network environment. Typically, a program module includes routines, programs, objects, components, data structures, etc. that have technical effects of performing specific tasks or realizing specific abstract data types. Machine executable instructions, associated data structures, and program modules represent program code examples for performing the steps of the method disclosed herein. A specific sequence of such executable instructions or associated data structures represents an example of the corresponding actions for implementing the functions described in these steps.

[0037] Steering Figure 3, a method 100 of operating an aircraft 10 includes, at 102, flying the aircraft 10 along a heading 36. At 104, at least one receiver / transmitter 62 receives a directional signal 63 from a signal source (a non-limiting example, a satellite 34) via an antenna 26 on the aircraft to define a received signal 66. At 106, a signal strength 70 associated with the received signal 66 may be determined. The signal strength 70 may be directly measured or calculated by the controller module 22 described herein using the received data associated with the directional signal 63. As a non-limiting example, a SATCOM receiver typically reports signal tracking strength as a ratio of received signal to noise. This is characterized for each type of receiver, and this information may be used to indicate a strong signal above a certain signal-to-noise ratio. At 108, a first heading observation 68 may be defined based on the signal strength 70. At 110, as a non-limiting example, an indicator 90 displayed at the aircraft display module 80 is used to indicate one of the heading change 72 or FOM 74 based on the first heading observation 68. As a non-limiting example, the heading change 72 and FOM 74 are generally application dependent. For pointing solutions, a heading change of 0.5 degrees may be acceptable to ensure that the antenna is pointed to within 1 degree of the satellite. For the purpose of aircraft navigation, the heading change may need to be less than 0.05 degrees. FOM is generally associated with position as an indication of the error associated with the position (FOM=1 means an error of less than 20 meters; FOM=2 means an error of less than 50 meters, etc.). For the disclosure herein, heading changes may be more applicable, but FOM is also considered. It should be understood that the method can be repeated or continuous, as shown in dashed lines. It will be understood that the aircraft continues throughout the flight.

[0038] Figure 4 A flow chart of a method 200 with additional input possibilities is shown. The method 200 is similar to the method 100 and, therefore, similar portions will be identified by similar numerals plus 100, with the understanding that the description of similar portions of the method 100 applies to the method 200 unless otherwise noted. The method 100 may include, at 212, determining a heading change 72 indicative of a quality of the heading 36 based at least on the first heading observation 68, and, at 214, receiving at least one of position (x), velocity (v), or timing (t) information from the receiver 42. The method 100 may further include, at 216, determining a second heading observation 68b based on at least one of the position (x), velocity (v), or timing (t) information, and determining the heading change 72 based on the first heading observation 68a and the second heading observation 68b.

[0039] Figure 51 shows a flow chart of another method 300 similar to the method 100, and therefore, similar parts will be identified by the same numerals increased by 200, and it should be understood that the description of similar parts of the method 100 applies to the method 300 unless otherwise specified. The method 300 also includes determining the heading change 72 based on the received inertial sensor information in the form of the inertial signal 50, the inertial signal 50 being pitch (θ), roll (θ) and pitch (θ). or at least one of the yaw (ψ) rate.

[0040] As in Figure 4 and Figure 5 Each of the methods described herein is represented by a dashed line, and the methods described herein may include iterative flying, receiving, determining, defining, and adjusting. It will be understood that method 100 only describes receiving SATCOM input, method 200 receives GPS information, and method 300 receives inertial sensor information. If the positioning signal 44 discussed herein is lost, the antenna 26 is more likely to remain within the beam width (α), so that the first heading observation 68a remains accurate longer when the satellite beam signal 63 is strong. Receiving SATCOM input, additional GPS information (if available), and additional inertial sensor information increases the likelihood of remaining accurate longer.

[0041] When the positioning signal from GPS is lost, the INS heading drifts and becomes less accurate. In a typical system, the heading change72 can exceed one degree of error in less than 20 minutes without a positioning signal from GPS. At 1 degree of heading error, the SATCOM system will typically disconnect.

[0042] In the case of a loss of the positioning signal 44 as discussed herein, the satellite beam signals 63 remain strong even without the positioning signal 44 and are used to generate heading observations. In this system, when using heading observations based on beam tracking strength 70, the heading drift is caused only by inertial system drift. For a typical INS used with a SATCOM system, this means that the heading change will not exceed one degree of error until at least four hours have passed.

[0043] The amount of heading drift of the aircraft 10 while flying can be limited to inertial system drift. In this way, the heading drift of the aircraft 10 can be resilient to reception losses from the GNSS receiver and the GPS receiver. The method described herein can be operable because the heading change 72 can be determined in an environment where radio navigation aids are denied.

[0044] The method 100 described herein includes providing at least one of a heading change 72 or a quality factor 74 based on the first heading observation to the controller module 22 of the antenna 26. As a non-limiting example, the orientation of the antenna 26 is adjusted based on at least one of the heading change 72 or the quality factor 74 by mechanically changing the orientation of the antenna 26. The heading deviation 72 may be maintained within a 1 degree error for a predetermined time period exceeding 20 minutes and up to or exceeding 4 hours.

[0045] The technical effects of the above embodiments include that the methods and apparatus described herein provide a pointing solution for a SATCOM system. Known inertial reference unit (IRU) installations rely on GPS heading observations to maintain a solution for a long time. When the GPS signal is lost, the IRU limits the connectivity of the SATCOM system. The methods and apparatus described herein extend the survivability of the IRU in an environment where GPS is lost or denied.

[0046] To the extent not yet described, the different features and structures of the various embodiments may be used in combination with each other as desired. A feature not shown in all embodiments does not mean that it cannot be interpreted as it may not be, but is for the sake of brevity of description. Therefore, whether or not a new embodiment is explicitly described, the various features of different embodiments may be mixed and matched as needed to form a new embodiment. The present disclosure covers all combinations or arrangements of the features described herein.

[0047] This written description uses examples to describe aspects of the disclosure, including the best mode, and also enables those skilled in the art to practice aspects of the disclosure, including making and using any device or system and performing any combined methods. The patentable scope of aspects of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ significantly from the literal language of the claims.

[0048] Other aspects of the disclosure are provided by the subject matter of the following clauses:

[0049] 1. A method for operating an aircraft, comprising: causing the aircraft to fly along a heading;

[0050] A directional signal is received from a signal source at an antenna on the aircraft to define a received signal; a signal strength of the received signal is determined; a first heading observation is defined based on the signal strength; and at least one of a heading change or a quality factor is indicated based on the first heading observation.

[0051] 2. A method according to any preceding clause, further comprising determining the heading change indicative of the quality of the heading based on at least the first heading observation.

[0052] 3. A method according to any preceding clause, further comprising receiving at least one of position, velocity or timing information from a GNSS receiver or a GPS receiver.

[0053] 4. A method according to any preceding clause, further comprising determining the second heading observation or the position of the aircraft based on at least one of position, velocity or timing information, and wherein determining a heading change is further based on the second heading observation.

[0054] 5. A method according to any preceding clause, further comprising receiving inertial sensor information, and wherein determining the heading change is further based on the inertial sensor information.

[0055] 6. A method according to any preceding clause, wherein the heading drift of the aircraft while in flight is limited to inertial system drift.

[0056] 7. A method according to any preceding clause, wherein the heading drift of the aircraft is resilient to loss of reception from the GNSS receiver and the GPS receiver.

[0057] 8. A method according to any preceding clause, wherein determining said heading change is operable in an environment where radio navigation aids are denied.

[0058] 9. A method according to any preceding clause, wherein said at least one of said heading change or said quality factor based on said first heading observation is provided to a controller of said antenna.

[0059] 10. The method of any preceding clause, further comprising adjusting the orientation of the antenna based on said at least one of said heading change or said quality factor.

[0060] 11. A method according to any of the preceding clauses, further comprising repeating said flying, receiving, determining, defining and adjusting.

[0061] 12. A method according to any preceding clause, wherein the heading change does not exceed an error of one degree within a predetermined amount of time.

[0062] 13. A method according to any preceding clause, wherein adjusting the orientation of the antenna comprises mechanically changing the orientation of the antenna.

[0063] 14. A communication system for a vehicle, comprising: a directional communication receiver, the directional communication receiver being configured to output a signal related to a beam tracking strength; an inertial reference module, the inertial reference module being configured to receive the beam tracking strength and to provide a heading observation based on the beam tracking strength, the inertial reference module being configured to determine a heading change indicating the quality of the vehicle's heading based at least on the heading observation and to provide an output related to the heading change, the inertial reference module being configured to provide the heading observation and output related to the heading change in an environment where radio navigation aids are denied; and at least one indicator, the at least one indicator being communicatively coupled to the inertial reference module and providing an indication related to the validity of the vehicle's heading based on the heading change.

[0064] 15. A communication system according to any preceding clause, wherein said inertial reference module comprises a look-up table having predetermined heading values ​​for said beam tracking strength.

[0065] 16. The communication system according to any preceding clause, wherein the at least one indicator is at least one of a quality factor or a numerical value of a heading change.

[0066] 17. A communication system according to any of the preceding clauses, wherein the directional communication receiver is a movable antenna assembly and the inertial reference module is further constructed to provide a pointing solution to the movable antenna assembly, and wherein the pointing solution includes at least two of the following: heading, pitch, roll, rate, position and timing data.

[0067] 18. A communication system according to any preceding clause, further comprising at least one inertial sensor configured to provide measurement information to the inertial reference module, and wherein the inertial reference module comprises a multi-state Kalman filter for correcting inertial sensor drift.

[0068] 19. A communication system according to any preceding clause, further comprising a global positioning system or a radio navigation aid, wherein the global positioning system or the radio navigation aid is configured to determine the absolute position of the vehicle and provide the determined position to the inertial reference module, and wherein the heading observation value is independent of the global positioning system or the radio navigation aid.

[0069] 20. A communication system according to any preceding clause, wherein the vehicle comprises an aircraft.

Claims

1. A method of operating an aircraft, It is characterized in that include: causing the aircraft to fly along a heading; receiving a directional signal from a signal source at an antenna on the aircraft to define a received signal, the antenna having an adjustable orientation and contained within or in communication with a satellite communications (SATCOM) system; determining a signal strength of the received signal; limiting a first heading observation based on the signal strength; indicating a heading change based on the first heading observation; and The heading change indicative of a quality of the heading is determined based on at least the first heading observation.

2. The method according to claim 1, It is characterized in that Further comprising receiving at least one of position, velocity, or timing information from a GNSS receiver or a GPS receiver.

3. The method according to claim 2, It is characterized in that Further comprising determining a second heading observation or the position of the aircraft based on the at least one of the position, velocity, or timing information, and wherein determining the heading change is further based on the second heading observation.

4. The method according to claim 3, It is characterized in that Further comprising receiving inertial sensor information, and wherein determining the heading change is further based on the inertial sensor information.

5. The method according to claim 4, It is characterized in that The heading drift of the aircraft during flight is limited to the drift of the inertial system.

6. The method according to claim 2, It is characterized in that The aircraft's heading drift is resilient to loss of reception from the GNSS receiver and the GPS receiver.

7. The method according to claim 1, It is characterized in that The heading change is determined to be operable in an environment where radio navigation aids are denied.

8. The method according to any one of claims 1 to 7, It is characterized in that The at least one of the heading change or a quality factor based on the first heading observation is provided to a controller of the antenna.

9. The method according to claim 8, It is characterized in that Further comprising adjusting the orientation of the antenna based on the at least one of the heading change or the quality factor.

10. The method according to claim 9, It is characterized in that Further comprising repeating said flying, receiving, determining, defining and adjusting.

11. The method according to claim 10, It is characterized in that The heading change does not exceed an error of one degree within a predetermined amount of time.

12. The method according to claim 9, It is characterized in that Adjusting the orientation of the antenna includes mechanically changing the orientation of the antenna.

13. A communication system for a vehicle, It is characterized in that include: a directional communication receiver configured to output a signal related to beam tracking strength, wherein the directional communication receiver includes an antenna on the vehicle to define a received signal, the antenna having an adjustable azimuth and being contained within or in communication with a satellite communication (SATCOM) system; an inertial reference module configured to receive the beam tracking strength and to provide heading observations based on the beam tracking strength, the inertial reference module configured to determine a heading change indicative of a quality of the vehicle's heading based at least on the heading observations and to provide an output associated with the heading change, the inertial reference module configured to provide the heading observations and output associated with the heading change in an environment where radio navigation aids are denied; and At least one indicator, communicatively coupled to the inertial reference module, provides an indication regarding validity of the heading of the vehicle based on the heading change.

14. The communication system according to claim 13, It is characterized in that The inertial reference module includes a lookup table having predetermined heading values ​​for the beam tracking strength.

15. The communication system according to claim 13, It is characterized in that The at least one indicator is at least one of a figure of merit or a numerical value of a heading change.

16. The communication system according to any one of claims 13 to 15, It is characterized in that The directional communication receiver is a movable antenna assembly, and the inertial reference module is further configured to provide a pointing solution to the movable antenna assembly, and wherein the pointing solution includes at least two of the following: heading, pitch, roll, rate, position, and timing data.

17. The communication system according to claim 16, It is characterized in that Further included is at least one inertial sensor configured to provide measurement information to the inertial reference module, and wherein the inertial reference module includes a multi-state Kalman filter for correcting for inertial sensor drift.

18. The communication system according to any one of claims 13 to 15, It is characterized in that Further comprising a global positioning system or a radio navigation aid configured to determine an absolute position of the vehicle and provide the determined position to the inertial reference module, and wherein the heading observations are independent of the global positioning system or the radio navigation aid.

19. The communication system according to any one of claims 13 to 15, It is characterized in that The vehicle includes an aircraft.

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