REDUNDANT DEVICE OF PILOTING SENSORS FOR A ROTARY-WING AIRCRAFT

Abstract

A device of piloting sensors for a rotary wing aircraft having at least two IMU inertial modules, at least two GNSS receivers having respective first fault detection and exclusion modules for detecting and excluding failures and covering distinct GNSS satellite navigation systems, at least two second FDE modules, at least two hybridizing platforms, and at least one third FDE module. The FDE modules enable signals that are of integrity and/or signals that are erroneous to be detected so as to exclude each GNSS system that is defective. In addition, each hybridizing platform makes it possible to determine a hybridized ground speed in order to delivering a ground speed for said aircraft that is accurate and of integrity.

Claims

1-13. (canceled)

14. A device of piloting sensors for a rotary wing aircraft, the system comprising: GNSS receivers for receiving constellations of at least two independent GNSS systems, the GNSS receivers receiving initial signals from a plurality of satellites; and at least one FDE module for detecting and excluding failures; wherein: each FDE module receives at least two input signals and delivers an output signal, each output signal including a measurement and an integrity state; each GNSS receiver includes a respective first FDE module for each GNSS system; each first FDE module receives and analyzes the initial signal, and it detects initial signals that are of integrity and/or initial signals that are erroneous; each GNSS receiver delivers a measurement and an integrity state concerning a first ground speed signal for the aircraft in a geographic frame of reference for at least one GNSS system on the basis of the initial signals that are of integrity and excluding the initial signals that are erroneous, if any; and the device of piloting sensors includes at least one second FDE module, each second FDE module being in communication with at least two of the GNSS receivers and receiving, analyzing, and comparing the first ground speed signal delivered by the at least two GNSS receivers, detecting first ground speed signals that are of integrity and/or first ground speed signals that are erroneous, each second FDE module then being capable of detecting and excluding each defective GNSS system that is supplying a first ground speed signal that is erroneous, and then of determining and delivering, where appropriate, a measurement and an integrity state of a second ground speed signal for the aircraft on the basis of at least two first ground speed signals that are of integrity.

15. A device of piloting sensors according to claim 14, wherein the device of piloting sensors includes at least three independent GNSS systems, and each second FDE module is in communication with at least three of the GNSS receivers and receives, analyzes, and compares the first ground speed signals delivered by the at least three GNSS receivers, detects first ground speed signals that are of integrity and/or first ground speed signals that are erroneous, each second FDE module then being capable of detecting and excluding each defective GNSS system that is supplying a first ground speed signal that is erroneous, and then for determining and delivering a measurement and an integrity state of a second ground speed signal for the aircraft on the basis of at least two first ground speed signals that are of integrity, while excluding the first ground speed signals that are erroneous, if any.

16. A device of piloting sensors according to claim 14, wherein the device of piloting sensors includes at least one IMU inertial module and at least one hybridizing platform, each IMU inertial module supplying inertial measurement signals characterizing accelerations and angular velocities of the aircraft; each hybridizing platform being in communication with a second FDE module and with an IMU inertial module; and each hybridizing platform receives and processes the inertial measurement signals and possibly a second ground speed signal, and then determines and delivers a measurement constituting a third ground speed signal for the aircraft on the basis of the inertial measurement signal and of a second ground speed signal that is of integrity, if any, the third ground speed signal being a pure inertial ground speed when the hybridizing platform does not receive any second ground speed signal that is of integrity, and being a hybridized ground speed when the hybridizing platform receives a second ground speed signal that is of integrity, the third ground speed signal then being available continuously.

17. A device of piloting sensors according to claim 16, wherein the device of piloting sensors includes at least two hybridizing platforms, at least two IMU inertial modules, and at least one third FDE module, a hybridizing platform and an IMU inertial module forming an inertial system, each third FDE module being in communication with at least two hybridizing platforms in order to determine and deliver a fourth ground speed signal, each third FDE module receiving, analyzing, and comparing the third ground speed signals delivered by the hybridizing platforms and detecting third ground speed signals that are of integrity and/or third ground speed signals that are erroneous, each third FDE module then being capable of detecting a failure in an inertial system and of excluding the inertial system on the basis of the third ground speed signals that are erroneous, if any, and then of determining and delivering, where appropriate, a measurement and an integrity state of the fourth ground speed signal for the aircraft on the basis of at least two third ground speed signals that are of integrity.

18. A device of piloting sensors according to claim 17, wherein the device of piloting sensors includes at least three hybridizing platforms, at least three IMU inertial modules, each third FDE module being in communication with at least three hybridizing platforms in order to determine and deliver a fourth ground speed signal, each third FDE module receiving, analyzing, and comparing the third ground speed signals delivered by the hybridizing platforms and detecting third ground speed signals that are of integrity and/or third ground speed signals that are erroneous, each third FDE module then being capable of detecting a failure in an inertial system and possibly of excluding the inertial system on the basis of the third ground speed signals that are erroneous, and then of determining and delivering a measurement and an integrity state of the fourth ground speed signal for the aircraft from at least two third ground speed signals that are of integrity, while excluding the third ground speed signals that are erroneous, if any.

19. A device of piloting sensors according to claim 17, wherein each third FDE module is in communication with at least one second FDE module so as to be capable of receiving, analyzing, and comparing at least one second ground speed signal and the third ground speed signals, of detecting and locating second and/or third ground speed signals that are of integrity and also second and/or third ground speed signals that are erroneous, and then of determining and delivering a measurement and an integrity state of the fourth ground speed signal for the aircraft on the basis of at least one second ground speed signal that is of integrity and/or at least two third ground speed signals that are of integrity, while excluding the second and/or third ground speed signals that are erroneous, if any.

20. A device of piloting sensors according to claim 17, wherein: each hybridizing platform includes a purely inertial virtual platform and two hybridizing error filters communicating with one another, a purely inertial virtual platform being in communication with an IMU inertial module, thereby forming an inertial unit; and the device of piloting sensors includes two inertial units, a computer having two calculation channels and four hybridizing error filters, each calculation channel putting a hybridizing error filter into communication firstly with a second FDE module and secondly with a third FDE module; each second FDE module being in communication with two hybridizing error filters for each calculation channel; and each third FDE module being in communication with two hybridizing filters for each calculation channel.

21. A device of piloting sensors according to claim 17, wherein at least one second FDE module and/or at least one third FDE module use(s) a median value determination method.

22. A device of piloting sensors according to claim 14, wherein at least one GNSS receiver includes an atomic clock.

23. A device of piloting sensors according to claim 14, wherein the GNSS receivers are in communication with GNSS systems selected from the group consisting of the GPS system; the GLONASS system; the GALILEO system; the QZSS system; the BEIDOU systems; and the IRIDIUM system.

24. A method of determining a ground speed of an aircraft, the method comprising the following steps: a first step of receiving initial navigation signals coming from a plurality of systems belonging to constellations of at least two independent GNSS systems; a second step of analyzing the initial navigation signals for each GNSS system; a third step of detecting initial navigation signals that are of integrity and/or initial signals that are erroneous; a fourth step of delivering a measurement and an integrity state of at least two first ground speed signals for the aircraft in a geographic reference frame for at least two independent GNSS systems from the initial signals that are of integrity, while excluding the initial signals that are erroneous, if any; a fifth step of analyzing and comparing the first ground speed signals; a sixth step of detecting first ground speed signals that are of integrity and/or first ground speed signals that are erroneous; a seventh step of detecting and excluding each defective GNSS system supplying a first ground speed signal that is erroneous; and an eighth step of determining and delivering a measurement and an integrity state of a second ground speed signal for the aircraft from at least two first ground speed signals that are of integrity, while excluding the first ground speed signals that are erroneous, if any.

25. A method of determining a ground speed for an aircraft according to claim 24, the method comprising the following steps: a ninth step of acquiring inertial measurement signals, the inertial measurement signals characterizing the accelerations and the angular velocities of the aircraft; a tenth step of processing each second ground speed signal and the inertial measurement signals; an eleventh step of determining and delivering at least one measurement constituting at least one third ground speed signal for the aircraft on the basis of the inertial measurement signals and of a second ground speed signal that is of integrity, if any, the third ground speed signal then being available continuously; a twelfth step of analyzing and comparing the third ground speed signals; a thirteenth step of detecting third ground speed signals that are of integrity and/or third ground speed signals that are erroneous; and a fourteenth step of determining and delivering a measurement and an integrity state of a fourth ground speed signal for the aircraft on the basis of at least two third ground speed signals that are of integrity, while excluding the third ground speed signals that are erroneous, if any.

26. A method of determining a ground speed of an aircraft according to claim 24, the method comprising the following steps: a ninth step of acquiring inertial measurement signals, the inertial measurement signals characterizing the accelerations and the angular velocities of the aircraft; a tenth step of processing each second ground speed signal and the inertial measurement signals; an eleventh step of determining and delivering at least one measurement constituting at least one third ground speed signal for the aircraft on the basis of the inertial measurement signals and of a second ground speed signal that is of integrity, if any, the third ground speed signal then being available continuously; a twelfth step of analyzing and comparing at least a second ground speed signal and the third ground speed signals; a thirteenth step of detecting and locating second ground speed signals that are of integrity and/or third ground speed signals that are of integrity together with second ground speed signals that are erroneous and/or third ground speed signals that are erroneous; and a fourteenth step of determining and delivering a measurement and an integrity state of a fourth ground speed signal of the aircraft on the basis of at least one second ground speed signal that is of integrity and/or at least two third ground speed signals that are of integrity, while excluding the second and/or third ground speed signals that are erroneous, if any.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0092] The invention and its advantages appear in greater detail from the context of the following description of embodiments given by way of illustration and with reference to the accompanying figures, in which:

[0093] FIG. 1 shows a rotary wing aircraft fitted with a device of piloting sensors of the invention; and

[0094] FIGS. 2 to 4 show various embodiments of a device of piloting sensors of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0095] Elements present in more than one of the figures are given the same references in each of them.

[0096] FIG. 1 shows a rotary wing aircraft 2 having a device of piloting sensors 1 of the invention. This device of piloting sensors 1 has four antennas 111, 112, 121, and 122. Two of the antennas 111 and 121 are positioned on top of the fuselage 3 of the aircraft 2, and two of the antennas 112 and 122 are positioned on the tail boom 4 of the aircraft 2. These antennas 111, 112, 121, and 122 serve to pick up initial navigation signals transmitted by various satellites 101, 102, 201, 202, 301, 302, 401, and 402.

[0097] The satellites 101, 102, 201, 202, 301, 302, 401, and 402 belong to respective GNSS systems 100, 200, 300, and 400 such as the GPS system, the GLONASS system, the GALILEO system, the QZSS system, and the BEIDOU systems.

[0098] In a first embodiment of the device of piloting sensors 1 as shown in FIG. 2, the device of piloting sensors 1 has four GNSS receivers 11, 12, 13, and 14 dedicated to respective ones of the GNSS systems 100, 200, 300, and 400, and a second fault detection and exclusion (FDE) module 31 for detecting and excluding failures connected to each GNSS receiver 11, 12, 13, and 14. The device of piloting sensors 1 is thus redundant in terms of GNSS systems 100, 200, 300, and 400, and it is capable of covering four GNSS systems 100, 200, 300, and 400 and thus mitigating any failure in at least one of these GNSS systems 100, 200, 300, and 400. Each GNSS receiver 11, 12, 13, and 14 is connected to two antennas 111 & 112, 121 & 122, 131 & 132, and 141 & 142 and it has a single first FDE module 21, 22, 23, or 24.

[0099] Each first FDE module 21, 22, 23, or 24 receives and analyzes the initial navigation signals from respective GNSS receiver 11, 12, 13, 14 in order to detect initial navigation signals that are of integrity and initial navigation signals that are erroneous.

[0100] Thereafter, each first FDE module 21, 22, 23, 24 can use these initial signals that are of integrity to determine a first ground speed signal for the aircraft 2. By way of example, this first ground speed signal of the aircraft 2 may be determined by a V-RAIM method of receiver autonomous integrity monitoring.

[0101] Specifically, each GNSS receiver 11, 12, 13, and 14 can deliver a first ground speed signal for the aircraft 2 while guaranteeing a first level of autonomous monitoring and integrity for this first ground speed signal in the event of a single satellite failure in a GNSS system 100, 200, 300, or 400.

[0102] The second FDE module 31 receives and compares the first ground speed signal coming from the four GNSS receivers 11, 12, 13, and 14. The second FDE module 31 can then detect multiple failures of at least one GNSS system 100, 200, 300, 400, and can exclude each GNSS system 100, 200, 300, 400 that is suffering from such a multiple failure and can determine a second ground speed signal for the aircraft 2.

[0103] The second FDE module 31 may apply the known median method for determining the second ground speed signal from two first ground speed signals.

[0104] In a second embodiment of the device of piloting sensors 1, as shown in FIG. 3, the device of piloting sensors 1 has two GNSS receivers 11, 12, each GNSS receiver 11, 12, being connected to two antennas 111 & 112 and 121 & 122, a second FDE module 31, two IMU inertial modules 51, 52, two hybridizing platforms 61, 62, and a third FDE module 41.

[0105] Furthermore, each GNSS receiver 11, 12 has a first FDE module 21, 22 together with an atomic clock 115, 125. The atomic clock 115, 125 is used as a frequency reference making it possible to reduce by one the number of satellites needed by each GNSS receiver 11, 12 in order to determine firstly a single satellite failure, and secondly a first ground speed signal.

[0106] The second FDE module 31 is connected to both of the GNSS receivers 11, 12 and to both of the hybridizing platforms 61, 62, and it delivers a second ground speed signal for the aircraft 2.

[0107] Each IMU inertial module 51, 52 supplies inertial measurement signals concerning accelerations and angular speeds, and it is connected to a hybridizing platform 61, 62. An IMU inertial module 51, 52 and the hybridizing platform 61, 62 to which it is connected thus together form an inertial system 71, 72. Each hybridizing platform 61, 62 receives the inertial measurements of accelerations and of angular velocities, and can thus determine a pure inertial ground signal for the aircraft 2.

[0108] Each hybridizing platform 61, 62 also receives the second ground speed signal for the aircraft 2 and can thus process this second ground speed signal and the pure inertial ground speed for the aircraft 2 in order to determine a third ground speed signal for the aircraft 2.

[0109] This third ground speed signal is a ground speed hybridized from the second ground speed signal and from the pure initial ground speed, when the second ground speed signal is of integrity. This third ground speed signal is equal to the pure inertial ground speed when the second ground speed signal is erroneous or unavailable. The third ground speed signal is thus available continuously.

[0110] The third FDE 41 module is connected to both of the hybridizing platforms 61, 62. This third FDE module 41 thus receives, analyzes, and compares the two third ground speed signals for the aircraft 2 in order to determine a fourth ground speed signal for the aircraft 2, e.g. using the median method.

[0111] The third FDE module 41 can thus detect inconsistencies between these third ground speed signals for the aircraft 2, e.g. resulting from a failure of a hybridizing platform 61, 62, or indeed of an IMU inertial module 51, 52.

[0112] In this second embodiment, the integrity and the availability of the fourth ground speed signal for the aircraft 2 is improved by using two IMU inertial modules 51, 52, and two GNSS receivers 11, 12 for two GNSS systems 100, 200 that are independent and distinct.

[0113] In a third embodiment of the device of piloting sensors 1, as shown in FIG. 4, the device of piloting sensors 1, as in the second embodiment, comprises two GNSS receivers 11, 12, a second FDE module 31, two IMU inertial modules 51, 52, two hybridizing platforms 61, 62, and a third FDE module 41. Each GNSS receiver 11, 12 is dedicated to a single GNSS system 100, 200, thus making it possible to cover two GNSS systems 100, 200, e.g. the GPS system and the GALILEO system.

[0114] The device of piloting sensors 1 also includes a computer 200 having two calculation channels 201 and 202. Each hybridizing platform 61, 62 comprises a purely inertial virtual platform 81, 82 and two hybridizing error filters 91 & 91′ and 92 & 92′, with one hybridizing error filter 91, 91′, 92, 92′ being situated in each calculation channel 201, 202.

[0115] In each calculation channel 201, 202, the second FDE module 31 is connected to both of the GNSS receivers 11, 12 and to two of the hybridizing error filters 91 & 91′ or 92 & 92′, and also to the third FDE module 41. The second FDE module 31 thus delivers a second ground speed signal that is of integrity for the aircraft 2.

[0116] A purely inertial virtual platform 81, 82 is connected to an IMU inertial module 51, 52 and thus co-operates with the IMU inertial module 51, 52 to form an inertial unit 101, 102 supplying a pure inertial ground speed for the aircraft 2.

[0117] Each hybridization error filter 91, 91′, 92, 92′ is preferably a Kalman filter.

[0118] Each hybridization error filter 91, 91′, 92, 92′ receives, analyzes, and compares the second ground speed signal for the aircraft 2 with the pure inertial ground speed for the aircraft 2, and then determines the third ground speed signal for the aircraft 2, which may be a hybridized ground speed or else a pure inertial ground speed. This third ground speed signal is thus available continuously.

[0119] The third FDE module 41 is connected to the hybridizing error filters 91, 91′, 92, 92′ and also to the second FDE module 31. This third FDE module 41 then receives, analyzes, and compares two third ground speed signals and the second ground speed signal, and then determines a fourth ground speed signal for the aircraft 2 using both of the calculation channels 201 and 202. The third FDE module 41 may use the median method, for example.

[0120] In addition, the third FDE module 41 can detect inconsistencies between the two third ground speed signals and the second ground speed signal for the aircraft 2 and can identify which ground speed signal is erroneous. The third FDE module 41 then makes it possible, where necessary, to exclude the erroneous ground speed signal.

[0121] As a result, the device of piloting sensors 1 makes it possible to ensure that a fourth ground speed signal is supplied continuously.

[0122] The operation of this third embodiment is analogous to the operation of the second embodiment. The use of two GNSS receivers 11, 12 and of two inertial units 101, 102 makes it possible to guarantee the availability and the integrity of the fourth ground speed signal for the aircraft 2, including in the event of there being no available second ground speed signal that is of integrity. Advantageously, the comparison between the second and third ground speed signals in the third FDE module 41 makes it possible to detect anomalies in a plurality of GNSS systems 100, 200 that might otherwise pass unnoticed in the second embodiment of the device of piloting sensors 1, e.g. due to scrambling or decoys. The integrity of this fourth ground speed signal is thus increased and it is then sufficient for a piloting system of the aircraft 2.

[0123] Finally, this device of piloting sensors 1 makes use of components that are standard, such as, in particular, two GNSS receivers 11, 12, and two inertial units 101, 102, for example, thereby reducing its costs.

[0124] Naturally, the present invention may be subjected to numerous variations as to its implementation. Although several embodiments are described, it will readily be understood that it is not conceivable to identify exhaustively all possible embodiments. It is naturally possible to envisage replacing any of the means described by equivalent means without going beyond the ambit of the present invention.