Aircraft guidance system and associated guidance method

Abstract

Aircraft guidance system and associated guidance method The present invention relates to a guidance system (10) for an aircraft comprising: - an imaging chain (14) configured to reconstruct an image of the external environment; - a surveillance chain (16) configured to detect obstacles on the route of the aircraft; - a radar module (12); - a management module (31) configured to control the operation of the radar module (12) between a surveillance mode and a mixed mode; - a post-processing module (32) configured to process reflected waves in order to transmit signals corresponding to imaging type waves to the imaging chain (14) and / or signals corresponding to surveillance type waves to the surveillance chain (16). Figure for abstract: Figure 1

Description

Title of the invention: Aircraft guidance system and associated guidance method

[0001] The present invention relates to a guidance system for an aircraft. The present invention also relates to a guidance method associated with this guidance system.

[0002] The field of the invention is that of the architecture of avionics systems, in particular for approach and landing assistance operations.

[0003] The descent of an aircraft on approach to the runway is a critical stage of the flight, particularly during low visibility conditions such as fog, rain, etc. The main problem here is to have sufficient visibility of the runway to be able to continue the descent and then initiate the landing.

[0004] In addition to the visibility of the runway itself, descent in low visibility presents a risk of collision with non-cooperative obstacles such as drones, large birds, cranes, pylons, etc. This risk is constantly increasing in the context of the proliferation of drones.

[0005] The problem thus consists of providing improved vision of the runway and its surroundings in conditions of degraded visibility, while providing detection of potential collisions with obstacles during descent.

[0006] To solve this problem, it is known in the state of the art to use an improved flight vision system, known by the acronym "EFVS" (from the English Enhanced Flight Vision System) which is based on a sensor (generally an infrared or multi-spectral sensor) which is mounted on the aircraft. This sensor makes it possible in certain degraded weather conditions to provide the crew with a better image of the runway than that seen by natural vision.

[0007] This system therefore makes it possible to continue landing the aircraft in degraded conditions (for example fog) and thus reduce the cancellation rate and diversions in the event of degraded weather conditions.

[0008] During the approach, the crew thus makes the decision whether or not to continue the landing at the decision height. In particular, the crew is authorized to continue the approach below this height if the visual references (corresponding to the runway lighting lamps or runway markings) not present in natural vision are present in the sensor image. Depending on different functionalities of the vision system, the approach can continue up to 100 feet from the ground corresponding to the height at which the crew must see the runway references in natural vision to complete the landing. Some vision systems allow also the guidance of the aircraft to the ground without the need for natural vision runway references. In this case it is not EFVS.

[0009] According to the state of the art, during an approach, certain instruments also allow the separation of the aircraft from other surrounding traffic. These instruments can be implemented either by air traffic control or by the crew in uncontrolled areas. In addition, for the case of collaborative traffic, the TCAS system (from the English Traffic Collision Avoidance System) which is on board the aircraft allows avoidance based on deterministic algorithms, or even on a dialogue between the equipment of two devices.

[0010] In any event, the crew must apply the basic rule, see and avoid, as much as possible, to protect themselves from collisions with non-collaborative traffic.

[0011] Generally, the step of detecting and identifying collaborative or non-collaborative traffic remains a delicate phase. Once the threat is detected, the crew must evaluate the trajectory convergences and decide whether an avoidance maneuver is necessary.

[0012] This maneuver must primarily rely on the rules of the art (priority to the aircraft coming from the right and below on final) and assume that the other aircraft will follow the same rules, or that its trajectory will remain unchanged.

[0013] However, in the case of non-collaborative traffic (notably drones), these assumptions are no longer valid.

[0014] There is also the problem of ground collisions with parked or taxiing vehicles or aircraft. Detecting an obstacle on the runway or taxiway is currently the responsibility of the crew. In low visibility conditions, the crew can only rely on the guarantee that procedures are being correctly followed by other airport users and that air traffic control may be able to detect an intruder in time.

[0015] The problem of detecting potential collisions with non-collaborative traffic is currently addressed through studies on the Detect and A void application which are based on an X or Ku band radar sensor to detect non-collaborative traffic in all weather conditions. These radars are however not designed to provide an accurate image of the landing strip due to their low angular resolution. The lack of space and the high cost of radar sensors deprive a large number of aircraft of these additional functions.

[0016] There is therefore currently no solution for providing an emergency collision detection and avoidance function at the same time as all-weather landing assistance. These two functionalities are therefore implemented separately by different instruments, which does not allow their actions to be coordinated. The need to monitor separate instruments thus increases the load cognitive required of the crew during landing or during any other critical phase of flight.

[0017] The present invention aims to solve these problems and in particular to propose an aircraft guidance system reducing the cognitive load required of the crew during landing or during any other critical flight phase. This guidance system combines in particular the functionality of improved vision of the landing runway with that of detecting collaborative or non-collaborative obstacles during this phase.

[0018] To this end, the invention relates to an aircraft guidance system comprising:

[0019] - an imaging chain configured to reconstruct an image of the environment exterior;

[0020] - a monitoring chain configured to detect obstacles on the road of the aircraft;

[0021] - a radar module capable of emitting millimeter waves and receiving waves thoughtful;

[0022] - a management module configured to control the operation of the module radar between a surveillance mode comprising the emission of only surveillance-type waves and a mixed mode comprising the emission of mixed-type waves combining surveillance-type waves and imaging-type waves;

[0023] - a post-processing module configured to process the reflected waves in order to to transmit signals corresponding to imaging type waves to the imaging chain and / or signals corresponding to surveillance type waves to the surveillance chain.

[0024] According to other advantageous aspects of the invention, the guidance system comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0025] - the management module is configured to determine a covered imaging volume by imaging type waves and a monitoring volume covered by monitoring type waves;

[0026] the monitoring volume being defined by an opening wider than the imaging volume or equal to that of the imaging volume;

[0027] a common volume being defined by the intersection of the monitoring volume and the imaging volume;

[0028] advantageously, the imaging volume being defined by a longer range than the monitoring volume;

[0029] - the monitoring volume is determined as a function of the speed of the aircraft, its altitude and assumptions about potential obstacles on its route;

[0030] - the imaging volume is determined as a function of the altitude of the aircraft and its route relative to a runway;

[0031] - the surveillance type waves include a watch wave sent periodically in the monitoring volume to detect a possible obstacle on the route of the aircraft and a confirmation wave sent towards the possible obstacle detected by the monitoring wave to confirm or deny this obstacle;

[0032] - which the management module is configured to switch the radar module in the mixed operating mode when the confirmation wave detects terrain and / or a landing strip;

[0033] - the management module is configured to send the confirmation wave to the land in a periodic manner;

[0034] - the management module is configured to switch the radar module into the mode of mixed operation or in the monitoring operating mode by comparing the aircraft altitude with a predetermined threshold;

[0035] - the predetermined threshold is between 400 feet and 600 feet, and advantageously substantially equal to 500 feet;

[0036] - the monitoring chain comprises a processing module configured to determine a collision trajectory with a potential obstacle detected by surveillance waves.

[0037] The invention also relates to a method for guiding an aircraft implemented by the system as defined above and comprising the following steps:

[0038] - in the monitoring mode, the emission of only waves of type monitoring ;

[0039] - in mixed mode, the emission of mixed type waves;

[0040] - reception of reflected waves and processing of reflected waves in order to transmit signals corresponding to imaging type waves in the imaging chain or monitoring type waves in the monitoring chain.

[0041] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which: - [Fig.l] [Fig.l] is a schematic representation of a guidance system according to the invention; - [Fig.2] [Fig.2] is a flowchart of a guidance method according to the invention, the guidance method being implemented by the guidance system of [Fig.l]; - [Fig.3] [Fig.4] [Fig.5] [Fig.6] Figures 3 to 6 are different illustrations of the implementation of the guidance method of [Fig.2].

[0042] [Fig.l] in fact shows a guidance system 10 according to the invention.

[0043] This guidance system 10 can be used to guide an aircraft, in particular during its landing phase (or approach phase).

[0044] According to other embodiments and depending on the nature of the aircraft, the guidance system 10 according to the invention can be used for any other phase of flight of the aircraft involving the use of improved vision, in particular of the terrain.

[0045] In the remainder of the description, by aircraft is meant any flying machine that can be piloted at least partially manually by an operator or a pilot or else can be piloted autonomously.

[0046] The aircraft may in particular correspond to an airplane, in particular an airliner, or to a helicopter, pilotable from a cockpit thereof by one or more pilots. According to other embodiments, the aircraft has a drone pilotable for example remotely by an operator from a remote cockpit. According to yet another embodiment, the aircraft has a drone pilotable in an at least partially autonomous manner.

[0047] According to the various examples, the guidance system 10 according to the invention can be at least partially on board the aircraft or at least partially arranged on the ground or in another aircraft.

[0048] In the example of [Fig.l], the guidance system 10 is entirely embedded in the aircraft for which it implements the guidance functionality.

[0049] With reference to [Fig.l], the guidance system 10 comprises a radar module 12, an imaging chain 14 and a surveillance chain 16.

[0050] The radar module 12 notably comprises a millimeter radar which is configured to emit millimeter waves and to receive waves reflected in response to these millimeter waves. For example, the radar module 12 comprises a single millimeter radar. Alternatively, the radar module comprises a plurality of millimeter radars configured to emit and to receive waves, in a grouped manner.

[0051] The or each radar of the radar module 12 is advantageously arranged on the fuselage of the aircraft, for example in a manner oriented towards the direction of its flight. In the case of an airplane, this radar may, for example, be arranged in a fixed manner. In the case, for example, of a helicopter, this radar may be arranged in a rotatable manner.

[0052] As will be explained in more detail below, the imaging chain 14 makes it possible to provide the crew of the aircraft with an improved view of the terrain and in particular, for example, of the aircraft's landing strip.

[0053] For this purpose, the imaging chain 14 can be connected for example to a database 22 providing symbols representative of different objects on the ground such as a landing strip.

[0054] The imaging chain 14 notably comprises an improved vision display 21 allowing the crew to view the terrain. This display 21 may have a conventional screen or any other display, for example the head-up display or a helmet worn by a pilot.

[0055] The monitoring chain 16 makes it possible to monitor the space around the aircraft to detect possible obstacles and, when this is the case, to advantageously propose an avoidance trajectory or to calculate a predictive trajectory of the detected obstacle.

[0056] For this purpose, the monitoring chain 16 can be connected to different avionics systems such as the TAWS system (from the English Terrain Awareness and Warning System which translates into French as impact warning and alarm system), the TCAS system (from the English Traffic Collision Avoidance System which translates into French as the traffic avoidance system) and the FW system (from the English Flight Warning which translates into French as the flight warning system). The monitoring chain 14 can also be connected to one or more displays displaying possible obstacles and / or alerts to the crew.

[0057] According to the invention, the two chains 14, 16 make it possible to exploit the waves reflected and received by the radar module 12 in order to implement the imaging and surveillance functionalities at the same time, during different flight phases.

[0058] To do this, the guidance system 10 comprises a management module 31 which is shared between the two chains 14, 16 and which is configured to control the operation of the radar module 12 between a surveillance mode and a mixed mode.

[0059] In particular, in the surveillance mode, the radar module 12 is configured to emit only surveillance type waves which are intended to monitor the space surrounding the aircraft and to possibly detect an obstacle and confirm its presence in this space.

[0060] In other words, the surveillance type waves are intended only for the surveillance chain 16.

[0061] In the mixed mode, the radar module 12 is configured to emit mixed type waves. These mixed type waves combine the surveillance type waves as explained previously and imaging type waves.

[0062] In particular, the imaging type waves are intended for the imaging chain 14 and make it possible to generate an improved view of the terrain, as explained previously.

[0063] This management module 31 is also connected to a device 35 making it possible to provide the altitude of the aircraft and to a control member 36 actuable by the crew.

[0064] The guidance system 10 further comprises a post-processing module 32 configured to receive all of the reflected waves received by the radar module 12 and to process these waves.

[0065] In particular, the post-processing module 32 makes it possible to convert the reflected waves into digital signals and to transmit these signals to the monitoring chain 16 and / or to the imaging chain 14.

[0066] Thus, the signals corresponding to the imaging type waves are transmitted by this post-processing module 32 to the imaging chain 14 and the signals corresponding to the monitoring type waves are transmitted to the monitoring chain 16.

[0067] The guidance system 10 further comprises a processing module 38 which is integrated into the monitoring chain 16 and which makes it possible in particular to determine a collision trajectory with a potential obstacle detected by the monitoring type waves. This module 38 also makes it possible to transmit information on a potential obstacle to the connected systems (TAWS, FW, TCAS) and / or to the display 23.

[0068] The modules 31, 32, 38 are for example implemented by a programmable logic circuit of the FPGA (Field Programmable Gate Array) type or at least partially in the form of software. In the latter case, these modules are for example stored in a suitable memory and are executable by one or more processors.

[0069] The guidance system 10 according to the invention makes it possible to implement a guidance method which will now be explained with reference to [Fig.2] presenting its flowchart and to Figures 3 to 6 illustrating the implementation of certain of the steps of this method.

[0070] It is initially considered that the radar module 12 operates in the surveillance mode. This operating mode of the radar module 12 is for example triggered by the management module 31 when the altitude of the aircraft is above a certain threshold. The altitude of the aircraft is for example provided by the device 35.

[0071] Said threshold is for example between 400 feet and 600 feet. This threshold is advantageously equal to 500 feet.

[0072] In some embodiments, the monitoring mode remains engaged by the management module 31 until the processing module 38 detects a terrain, as will be explained in more detail later.

[0073] When the guidance system 10 is used during an approach phase of the aircraft, the surveillance mode is operational when the aircraft is still relatively far from the landing runway. This distance is determined precisely by the altitude threshold above which the management module 31 switches the radar module 12 into the mixed mode.

[0074] This case is notably illustrated in the upper part of [Fig.3] where the altitude of the aircraft is substantially equal to 5000 feet, which means that only the surveillance mode is engaged.

[0075] During a step 110 of this monitoring mode MS, the management module 31 commands the radar module 12 to emit a monitoring wave periodically.

[0076] In particular, the management module 31 determines a monitoring waveform to be transmitted in order to cover a monitoring volume Vs visible in [Fig.3].

[0077] This monitoring volume Vs has in particular a cone which is oriented towards the direction of movement of the aircraft and which extends above and below the horizontal plane comprising the aircraft.

[0078] Advantageously, and as can be seen in [Fig. 3], this cone has a larger opening below the horizontal plane comprising the aircraft than above this plane. This is particularly advantageous during the approach phase of the aircraft.

[0079] The monitoring volume Vs is for example determined according to techniques known per se.

[0080] In particular, the monitoring volume Vs is determined by the management module 31 as a function of the speed of the aircraft, its altitude and assumptions about potential obstacles on the route of the aircraft.

[0081] In particular, these assumptions about obstacles include vertical and horizontal speed envelopes of a possible obstacle as well as minimum SER (Radar Cross Section) values. The SER value corresponds to the "size" of an object seen by the radar. Given the sensitivity of the radar in the surveillance mode, it will be able to detect objects of a given SER value at a given distance with a certain probability.

[0082] During a following step 120, the post-processing module 32 receives reflected waves corresponding to the standby waves and transforms them into digital signals to transmit them to the processing module 38.

[0083] Then, the processing module 38 analyzes the received signals and when no obstacle is detected, the processing module 38 commands the management module 31 to continue to emit the standby waves during step 110.

[0084] When, on the contrary, the processing module 38 detects a possible obstacle by analyzing the signals corresponding to the standby waves, it commands the management module 31 to emit a confirmation wave during a following step 130.

[0085] In particular, the confirmation wave is focused in the direction of the possible obstacle detected, which makes it possible to concentrate the power in the target angular sector before confirming or denying the presence of such an obstacle.

[0086] The confirmation wave also has a greater detection distance than the standby waves.

[0087] During a following step 140, the post-processing module 32 then receives the reflected waves corresponding to the confirmation wave sent by the radar module 12 and transforms these reflected waves into corresponding digital signals. Then, it transmits these signals to the processing module 38 which analyzes these signals.

[0088] When the presence of an obstacle is not confirmed, the doubt is removed and the management module 31 then continues to control the radar module 12 in order to emit the monitoring waves during step 110.

[0089] When, on the contrary, the presence of an obstacle is confirmed, the processing module 38 raises an alert during a step 150.

[0090] According to different embodiments, this alert can be communicated to the crew as well as to the different avionics systems such as for example the TCAS system.

[0091] Advantageously, during this step, the processing module 38 determines a collision trajectory with the detected obstacle.

[0092] For this, the processing module 38 can for example analyze the speed of the obstacle, the direction of its movement as well as a certain number of hypotheses.

[0093] This collision trajectory can then be communicated to the crew and / or to an avionics system such as the TCAS system for example.

[0094] The operation of the MS monitoring mode is also schematically illustrated in [Fig.5].

[0095] In particular, with reference to this figure, the radar module 12 emits the monitoring waves Sv until the processing module 38 detects a possible obstacle B. When such an obstacle B is detected by the monitoring waves Sv, the radar module 12 is commanded to emit a confirmation wave Sc towards the obstacle B. In this case, the processing module 38 then analyzes the signal corresponding to this confirmation wave and confirms or denies the presence of such an obstacle B. As explained previously, when such an obstacle is confirmed, the processing module 38 can implement a particular processing, such as for example the determination of a collision trajectory.

[0096] Otherwise, the processing module 38 continues to analyze the signals corresponding to the standby waves Sv as explained previously.

[0097] In certain embodiments of the invention, the management module 31 is further configured to periodically send a confirmation wave Sc to the terrain without a possible obstacle being detected by the monitoring waves. This is also illustrated in [Fig. 5] in which the confirmation wave Sc is sent to track P without this track P being pre-detected by the corresponding monitoring waves.

[0098] This confirmation wave Sc is then sent periodically with a predetermined periodicity, for example.

[0099] The monitoring mode MS is implemented by the guidance system 10 until, during a step 160, the management module 31 determines that the altitude of the aircraft is below the predetermined threshold or when the processing module 38 detects terrain by sending a confirmation wave periodically.

[0100] During this step 160, the management module 31 then switches the radar module 12 into the mixed MM operating mode.

[0101] During an initial step 210 of this mixed mode, the management module 31 determines a mixed type waveform which then optimally combines the monitoring type waves and the imaging type waves.

[0102] In this mixed mode, the management module 31 determines not only the monitoring volume Vs as explained previously but also an imaging volume V! visible in [Fig.3].

[0103] As can be seen in [Fig.4], this imaging volume Vi also has a cone extending from the aircraft in the direction of movement of the latter.

[0104] Unlike the monitoring volume Vs, the imaging volume V has a smaller opening than the monitoring volume Vs but a preferentially greater range than the latter.

[0105] Furthermore, as can be seen in [Fig.3], the imaging volume Vi can preferably extend only below the horizontal plane comprising the aircraft, advantageously in the direction of the landing runway P. This imaging volume V! can also have a margin in the angular opening to be able to take into account the pitching movements of the aircraft without losing the image.

[0106] The imaging volume Vi can also be determined according to techniques known per se and in particular as a function of the route and the altitude of the aircraft, relative to the landing runway.

[0107] The imaging volumes V! and monitoring volumes Vs have an intersection corresponding to their common volume Vc visible in figures 3 and 4.

[0108] In this common volume Vc, the wake-up waves act as imaging type waves which can then be used for improved vision.

[0109] Outside the common volume Vc, the waves sent by the radar module 12 present either only the surveillance type waves (for the volume monitoring Vs) or only imaging type waves (in the imaging volume Vi).

[0110] After step 210, the guidance system 10 then implements steps 220 to 250 which are analogous to steps 120 to 150 of the MS monitoring mode, described previously. These steps 220 to 250 will therefore not be described in detail subsequently.

[0111] In parallel, the guidance system 10 also implements step 270 during which the post-processing module 32 transmits the signals corresponding to the imaging type waves to the imaging chain 14 and in particular to the display 21.

[0112] These signals are then used to reconstruct an improved view of the aircraft's external environment, using techniques known per se.

[0113] In particular, for the common volume Vc, steps 220 and 270 are implemented in parallel by the post-processing module 32 when the reflected waves correspond to both the imaging type waves and the monitoring type waves.

[0114] Similarly to [Fig.5], [Fig.6] illustrates the implementation of the mixed MM mode of operation of the guidance system 10.

[0115] In particular, as in the previous case, this [Fig.6] illustrates the emission by the radar module 12 of the monitoring waves Sv as well as the confirmation waves Sc to confirm or deny an obstacle B or periodically to detect terrain and / or a runway P.

[0116] Unlike the previous case, the standby waves Sv* and Sv4 are sent into the common volume Vc. In this case, these waves are then used both by the processing module 38 as well as by the imaging chain 14 and in particular by the display 21.

[0117] On the contrary, the standby waves Sv2, Sv3, Sv5 and Sv6 are sent into the exclusive part of the monitoring volume VS and are therefore used only by the processing module 38 and not by the imaging chain 14.

[0118] It is then understood that the present invention presents a certain number of advantages.

[0119] In particular, the guidance system according to the invention combines the functionalities of surveillance and imaging in a single system.

[0120] Thus, the crew can interact with such a system in a centralized manner, which makes it possible to reduce its cognitive load during certain flight phases, in particular during the approach phase or any other critical phases.

[0121] Furthermore, the guidance system according to the invention uses the same millimeter radar for several functionalities as well as the same management module for determining a waveform for this millimeter radar and the same post-processing module for processing the reflected waves. This then reduces the size of the system as well as its complexity.

[0122] Of course, other embodiments are also possible.

Claims

Claims

1. Guidance system (10) of an aircraft comprising: - an imaging chain (14) configured to reconstruct an image of the external environment; - a surveillance chain (16) configured to detect obstacles on the route of the aircraft; - a radar module (12) capable of emitting millimeter waves and receiving reflected waves; - a management module (31) configured to control the operation of the radar module (12) between a surveillance mode comprising the emission only of surveillance type waves and a mixed mode comprising the emission of mixed type waves combining surveillance type waves and imaging type waves; - a post-processing module (32) configured to process the reflected waves in order to transmit signals corresponding to the imaging type waves to the imaging chain (14) and / or signals corresponding to the surveillance type waves to the surveillance chain (16).

2. System (10) according to claim 1, wherein the management module (31) is configured to determine an imaging volume (V!) covered by the imaging type waves and a monitoring volume (Vs) covered by the monitoring type waves; the monitoring volume (Vs) being defined by an opening wider than the imaging volume (VO or equal to that of the imaging volume (Vi); a common volume (Vc) being defined by the intersection of the monitoring volume (Vs) and the imaging volume (VO; advantageously, the imaging volume (Vi) being defined by a range longer than the monitoring volume (Vs).

3. System (10) according to claim 2, in which the monitoring volume (Vs) is determined as a function of the speed of the aircraft, its altitude and assumptions about potential obstacles on its route.

4. The system (10) of claim 2 or 3, wherein the imaging volume (VO) is determined as a function of the aircraft's altitude and its course relative to a runway.

5. System (10) according to any one of the preceding claims taken in combination with claim 2, in which the surveillance type waves comprise a monitoring wave sent periodically into the monitoring volume (Vs) to detect a possible obstacle on the route of the aircraft and a confirmation wave sent towards the possible obstacle detected by the monitoring wave to confirm or deny this obstacle.

6. System (10) according to claim 5, wherein the management module (31) is configured to switch the radar module (12) into the mixed operating mode when the confirmation wave detects terrain and / or a landing strip.

7. System (10) according to claim 6, wherein the management module (31) is configured to send the confirmation wave to the field in a periodic manner.

8. System (10) according to any one of the preceding claims, wherein the management module (31) is configured to switch the radar module (12) into the mixed operating mode or into the surveillance operating mode by comparing the altitude of the aircraft with a predetermined threshold.

9. System (10) according to claim 8, wherein the predetermined threshold is between 400 feet and 600 feet, and advantageously substantially equal to 500 feet.

10. System (10) according to any one of the preceding claims, in which the monitoring chain (16) comprises a processing module (38) configured to determine a collision trajectory with a potential obstacle detected by the monitoring type waves.

11. Method for guiding an aircraft implemented by the system (10) according to any one of the preceding claims and comprising the following steps: - in the surveillance mode, the emission (110) of only the surveillance type waves; - in the mixed mode, the emission (210) of the mixed type waves; - reception (120, 220, 270) of the reflected waves and processing of the reflected waves in order to transmit signals corresponding to the imaging type waves to the imaging chain (14) or to the surveillance type waves to the surveillance chain (16).

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