Multi-trajectory terrain avoidance method based on aircraft performance

Abstract

The method comprises the following steps: S1, obtaining the maneuvering performance parameters and the current flight state data of the aircraft; S2, predicting three flight avoidance paths in the front, left and right directions of the aircraft according to the maneuvering performance parameters and the flight state data of the aircraft by using a three-degree-of-freedom motion model; S3, extracting the current position of the aircraft and the surrounding on-board digital terrain data in real time according to the flight state data; S4, extracting the terrain envelope of the flight prediction trajectory by using a terrain scanning algorithm according to the flight state data and the flight prediction trajectory; S5, identifying and evaluating the terrain threat of each flight avoidance path according to the prediction avoidance trajectory of the aircraft and the corresponding terrain envelope data; S6, giving voice and / or light prompts according to the threat evaluation results to remind the pilot to perform corresponding avoidance maneuvers; and S7, the pilot performs avoidance maneuvers according to the avoidance prompts.

Description

Technical Field

[0001] This invention relates to the field of aviation control technology, and in particular, to a multi-track terrain avoidance method based on aircraft performance. Background Technology

[0002] Terrain awareness and avoidance systems are an important component of current avionics systems. Their basic principle is to predict the aircraft's flight trajectory based on the aircraft's current flight status and performance parameters, and to acquire real-time terrain situation information around the aircraft, generating a terrain envelope. Based on the relationship between the flight trajectory and the terrain envelope, avoidance maneuvers are performed, thereby effectively avoiding controllable flight-to-ground accidents such as aircraft crashing into mountains or ground, improving flight safety and enhancing combat effectiveness.

[0003] Traditional ground proximity warning devices, terrain perception and warning systems, enhanced ground proximity warning systems, and automatic ground collision avoidance systems primarily extract terrain information in the forward-looking direction based on the aircraft's current status. They then identify obstacles in the forward-looking direction for a future period and promptly issue warnings via voice and lights to avoid dangerous terrain. However, traditional terrain perception and warning algorithms do not fully consider the aircraft's lateral maneuverability, potentially leading to premature warnings from the airborne terrain perception and warning system, triggering evasive maneuvers. Therefore, terrain perception and warning systems urgently need to fully consider the aircraft's maneuverability and flight status data, performing terrain obstacle identification and analysis based on the surrounding terrain information to improve system reliability. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that the lateral maneuverability of aircraft is not fully considered in the prior art. This invention provides a multi-track terrain avoidance method based on aircraft performance.

[0005] The technical solution of this invention is implemented as follows: a multi-track terrain avoidance method based on aircraft performance, characterized by comprising the following steps:

[0006] Step S1: Obtain the aircraft's maneuverability parameters and current flight status data, such as position data, attitude data, and directional overload parameters;

[0007] Step S2: Based on the aircraft's maneuverability parameters and flight data such as position data and attitude data, a three-degree-of-freedom motion model is used to predict the aircraft's flight avoidance paths in the forward-looking direction, left-side direction, and right-side direction, and the corresponding flight avoidance trajectories are obtained.

[0008] Step S3: Based on the flight status data, extract the aircraft's current position and surrounding airborne digital terrain data in real time;

[0009] Step S4: Based on the flight status data and the predicted flight trajectory, extract the terrain envelope of the predicted flight trajectory using a terrain scanning algorithm;

[0010] Step S5: Identify and assess the terrain threats of each flight avoidance path based on the aircraft's predicted avoidance trajectory and the corresponding terrain envelope data.

[0011] Step S6: Based on the threat assessment results, provide voice and / or light cues to remind the pilot to perform appropriate evasive maneuvers; and,

[0012] Step S7: The pilot performs evasive maneuvers according to the evasive prompts.

[0013] As a preferred embodiment of a multi-track terrain avoidance method based on aircraft performance, in step S1, terrain avoidance paths are designed for the aircraft's forward-looking direction, left-side direction (45° or 30°), and right-side direction (45° or 30°) based on the aircraft's maximum normal overload system, maximum turning rate, maximum climb rate, and critical angle of attack. Preferably, a roll-to-level pull-up maneuver is used in the forward-looking direction until the pull-up reaches the aircraft's critical angle of attack. Preferably, a maximum turning rate and a fixed roll angle are used for avoidance maneuvers in the left and right-side directions.

[0014] As a preferred option for a multi-trajectory terrain avoidance method based on aircraft performance, in step S2, based on the aircraft terrain avoidance path, a three-degree-of-freedom aircraft trajectory prediction model is used with the current position and current attitude in the aircraft flight status data to predict the aircraft terrain avoidance paths on the left, forward and right sides.

[0015]

[0016] Where x, y are the aircraft's plane coordinates, h is the aircraft's altitude, V is the flight speed, γ is the track inclination angle, χ is the track azimuth angle, L is lift, D is drag, M is the aircraft's mass, T is the engine thrust, α is the angle of attack, and μ is the track roll angle.

[0017] As a preferred option for a multi-trajectory terrain avoidance method based on aircraft performance, in step S3, terrain data of the aircraft's current position and a certain range around it are extracted from the aircraft's flight status data to provide basic geographic information data for terrain envelope generation and terrain threat assessment.

[0018] As a preferred option for a multi-track terrain avoidance method based on aircraft performance, in step S4, a terrain scanning area is generated based on the accuracy of the aircraft's current position and the accuracy of the aircraft's predicted trajectory. Then, terrain profile data on each aircraft terrain avoidance path is extracted within the terrain scanning area. Finally, considering terrain data errors, aircraft navigation and positioning data errors, and the minimum safe flight altitude, a two-dimensional terrain envelope corresponding to each aircraft terrain avoidance path is obtained.

[0019] As a preferred option for a multi-track terrain avoidance method based on aircraft performance, in step S5, the predicted avoidance path of the aircraft is compared with the corresponding terrain envelope. If the predicted avoidance path of the aircraft intersects with the terrain envelope, it is determined that the terrain avoidance path of the aircraft in that direction has a terrain threat.

[0020] As a preferred option for a multi-track terrain avoidance method based on aircraft performance, in step S6, if only one of the aircraft's flight avoidance paths is free from terrain threats, the aircraft will use that path for terrain avoidance; if only two of the three avoidance paths (forward-looking, left-side, and right-side) are free from terrain threats, the aircraft will choose one of those two paths for terrain avoidance; if none of the three avoidance paths (forward-looking, left-side, and right-side) are free from terrain threats, the aircraft will maintain its current flight state.

[0021] As a preferred embodiment of a multi-track terrain avoidance method based on aircraft performance, the present invention relates to a computer device, the computer device including a processor and a memory, the memory storing at least one instruction and airborne digital map data, the instruction being loaded and executed by the processor to implement the operation performed by the method.

[0022] Compared with the prior art, the beneficial effects of the present invention are: reducing the false alarm rate and improving aircraft flight safety. Attached Figure Description

[0023] Figure 1 This is a flowchart of the method of the present invention.

[0024] Figure 2 This refers to the flight avoidance path and terrain envelope in the forward-looking direction of this invention.

[0025] Figure 3 This refers to the flight avoidance path and terrain envelope of the multi-trajectory system in this invention. Detailed Implementation

[0026] The technical solution of the present invention will be described below through specific examples, but the following embodiments do not limit the scope of protection of the present invention.

[0027] Please see Figures 1 to 3The figure shows a multi-track terrain avoidance method based on aircraft performance, which involves the field of avionics technology, especially the field of terrain avoidance technology in aircraft airborne systems widely used in aircraft. Such systems include, but are not limited to, specific products such as ground proximity warning systems, automatic ground proximity collision avoidance systems, and terrain prompting and warning systems.

[0028] The multi-track terrain avoidance method based on aircraft performance first designs a maneuver avoidance strategy based on the aircraft's maneuverability parameters. Then, it accurately predicts the maneuver avoidance path based on the aircraft's current state parameters. Finally, it identifies and assesses terrain threats based on airborne digital terrain data on the predicted flight path and provides warnings and maneuver avoidance based on the judgment results, thereby reducing the false alarm rate of the system and improving the flight safety of the aircraft.

[0029] Specifically, it includes the following steps:

[0030] Step A: Based on the aircraft's performance parameters such as normal overload coefficient, maximum climb rate, maximum turn rate, and critical angle of attack, design the aircraft's terrain maneuvering avoidance strategy.

[0031] Step B: Based on the aircraft's current flight status, such as current flight position and current attitude data, and based on the aircraft's performance parameters, predict multiple terrain avoidance paths (left, center, and right) for the aircraft.

[0032] Step C: Based on the aircraft's flight status parameters, extract in real time airborne digital terrain data within a certain range around the current aircraft position;

[0033] Step D: Based on the current flight status parameters and the predicted flight trajectory, use the terrain scanning algorithm to extract the terrain envelope of the aircraft's predicted avoidance trajectory;

[0034] Step E: Identify and assess terrain threats based on the aircraft's predicted avoidance trajectory and the corresponding terrain envelope data;

[0035] Step F: Based on the terrain threat assessment results of multiple aircraft terrain avoidance paths, provide voice or light prompts to remind the pilot to perform corresponding evasive maneuvers;

[0036] Step H: The pilot performs terrain avoidance maneuvers according to the results of light or voice prompts, thereby avoiding terrain threats.

[0037] The terrain maneuver avoidance strategy in step A is designed based on the aircraft's performance parameters, such as the aircraft's maximum normal overload system, maximum turn rate, maximum climb rate, and critical angle of attack. The design considers the aircraft's terrain avoidance maneuvers in the forward-looking direction, left-side direction (45° or 30°), and right-side direction (45° or 30°). In the forward-looking direction, a roll-to-level pull-up maneuver is used until the pull-up reaches the aircraft's critical angle of attack. In the left and right-side directions, the maximum turn rate and a fixed roll angle are used for avoidance maneuvers.

[0038] The terrain avoidance path prediction in step B is mainly based on the aircraft's terrain avoidance maneuver strategy. Using the aircraft's current flight status data (current position and attitude), a three-degree-of-freedom aircraft trajectory prediction model is used to predict the aircraft's left-side, forward-looking, and right-side flight avoidance paths.

[0039]

[0040] Where x, y are the aircraft's plane coordinates, h is the aircraft's altitude, V is the flight speed, γ is the track inclination angle, χ is the track azimuth angle, L is lift, D is drag, M is the aircraft's mass, T is the engine thrust, α is the angle of attack, and μ is the track roll angle.

[0041] The airborne digital terrain data extraction in step C is mainly based on the aircraft's current position data. It extracts terrain data of the current position and a certain surrounding area to provide basic geographic information data for terrain envelope generation and terrain threat assessment.

[0042] The terrain envelope generation in step D mainly involves generating a terrain scanning area based on the accuracy of the aircraft's current position and the accuracy of the aircraft's predicted trajectory. Then, terrain profile data on each aircraft terrain avoidance path is extracted within the terrain scanning area. Finally, considering terrain data errors, aircraft navigation and positioning data errors, and the minimum safe flight altitude, a two-dimensional terrain envelope corresponding to each aircraft terrain avoidance path is obtained.

[0043] The identification and assessment of terrain threats in step E mainly involves comparing the aircraft's predicted avoidance path with the corresponding terrain envelope. If the aircraft's predicted avoidance path intersects with the terrain envelope, it indicates that there is a terrain threat in the aircraft's terrain avoidance path in that direction, and that aircraft terrain avoidance path is not feasible.

[0044] The terrain avoidance maneuver in step H is mainly based on the identification and assessment results of the terrain threat in step E. If only one of the aircraft's terrain avoidance paths has a terrain threat, then either of the other two terrain avoidance paths is selected for terrain avoidance. If only one maneuver avoidance path has no terrain threat, then terrain avoidance is performed along that predicted flight avoidance path. If all three aircraft avoidance maneuver paths have no terrain threat, then the aircraft retains its current state.

[0045] The method of use is as follows: The multi-track terrain avoidance method based on aircraft performance is encapsulated as a software module and embedded in the main program of the aircraft computer equipment to avoid terrain threats around the aircraft, thereby improving the safety of the aircraft.

[0046] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A multi-trajectory terrain avoidance method based on aircraft performance, characterized in that, It includes the following steps, Step S1: Obtain the aircraft's maneuverability parameters and current flight status data, including: position data, attitude data, and normal overload parameters; Step S2: Based on the aircraft's maneuverability parameters and current flight status data, a three-degree-of-freedom aircraft dynamic trajectory prediction model is used to predict the terrain avoidance paths of the aircraft in the forward-looking direction, left-side direction, and right-side direction, and the corresponding flight avoidance trajectories are obtained. Step S3: Based on the current flight status data, extract the aircraft's current position and surrounding airborne digital terrain data in real time; Step S4: Based on the current flight status data and flight avoidance trajectory, extract the terrain envelope of the flight avoidance trajectory using a terrain scanning algorithm: Generate a terrain scanning area based on the accuracy of the aircraft's current position and the accuracy of the aircraft's predicted trajectory, then extract the terrain profile data on each aircraft terrain avoidance path within the terrain scanning area, and finally consider the terrain data error, aircraft navigation and positioning data error, and minimum safe flight altitude to obtain the two-dimensional terrain envelope corresponding to each aircraft terrain avoidance path. Step S5: Identify and assess the terrain threats of each terrain avoidance path based on the flight avoidance trajectory and the corresponding terrain envelope. Step S6: Based on the threat assessment results, provide voice and / or light prompts to remind the pilot to perform appropriate evasive maneuvers; Step S7: The pilot performs evasive maneuvers according to the evasive prompts.

2. A multi-trajectory terrain avoidance method based on aircraft performance according to claim 1, characterized in that, In step S2, terrain avoidance paths are designed for the aircraft in the forward, left, and right directions based on the aircraft's maximum normal overload coefficient, maximum turning rate, maximum climb rate, and critical angle of attack. In the forward direction, a roll-to-level pull-up maneuver is used until the pull-up reaches the aircraft's critical angle of attack. In the left and right directions, avoidance maneuvers are performed with the maximum turning rate and a fixed roll angle.

3. The multi-track terrain avoidance method based on aircraft performance according to claim 1, characterized in that, In step S2, based on the aircraft's terrain avoidance maneuvering strategy, the aircraft's current position and attitude are used in the flight status data, and a three-degree-of-freedom aircraft dynamic trajectory prediction model is adopted to predict the terrain avoidance paths of the aircraft in the left, forward, and right directions. Where x, y are the aircraft's plane coordinates, h is the aircraft's altitude, V is the flight speed, γ is the track inclination angle, χ is the track azimuth angle, L is lift, D is drag, M is the aircraft's mass, T is the engine thrust, α is the angle of attack, and μ is the track roll angle.

4. The multi-track terrain avoidance method based on aircraft performance according to claim 1, characterized in that, In step S3, the current location of the aircraft and the terrain data in the surrounding area are extracted from the flight status data to provide basic geographic information data for terrain envelope generation and terrain threat assessment.

5. The multi-track terrain avoidance method based on aircraft performance according to claim 1, characterized in that, In step S5, the terrain avoidance path of the aircraft is compared with the corresponding terrain envelope. If the terrain avoidance path of the aircraft intersects with the terrain envelope, it is determined that the terrain avoidance path of the aircraft in that direction is subject to terrain threat.

6. The multi-track terrain avoidance method based on aircraft performance according to claim 1, characterized in that, In step S6, if only one of the aircraft's terrain avoidance paths is free from terrain threats, the aircraft will use that path to avoid the terrain. If only two of the three paths—the forward-looking avoidance path, the left-side avoidance path, and the right-side avoidance path—are free from terrain threats, the aircraft will choose one of those two paths to avoid the terrain. If none of the three paths—the forward-looking avoidance path, the left-side avoidance path, and the right-side avoidance path—are free from terrain threats, the aircraft will maintain its current flight status.

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