Method and device for reducing asynchronous interference false alarm of airborne collision avoidance system

Abstract

The invention provides a method and a device for reducing asynchronous interference false alarm of an airborne collision avoidance system, and aims at solving the problem that the normal function of the airborne collision avoidance system is not influenced and the standard requirement is met through the method based on a response signal received by the airborne collision avoidance system. The asynchronous interference signals are filtered out to a certain extent by performing'strength-distance 'correlation judgment on the response signals in the receiving decoding window and adding a false target confirmation process within the minimum protection distance, so that the probability of forming false targets and false alarms by the asynchronous interference signals is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of avionics, and in particular relates to a method and a device for reducing asynchronous interference false alarms in an airborne collision avoidance system. Background Art

[0002] The Airborne Collision Avoidance System (ACAS) is an essential airborne device to prevent dangerous approaches and collisions between aircraft in the air. It works independently of the ground traffic control system. The system uses the same working mode and communication link as the secondary radar to effectively track and monitor aircraft equipped with air traffic control transponders in the nearby airspace, obtain and calculate the distance, speed, flight altitude, direction and other information of the target aircraft, generate traffic warnings based on the target's trajectory, or further generate decision warnings based on the threat level. It promptly reminds pilots to take measures to avoid danger and prevent the aircraft from colliding with other aircraft. The flight practice in recent years has proved that the airborne collision avoidance system is the last line of defense to prevent aircraft collisions in the air. It uses the "air-to-air" communication between aircraft in the air, overcoming the limitations of "ground-to-air" communication between ground secondary radar and aircraft for traffic control. It is of great significance in dealing with dangerous approaches in the air and avoiding aircraft collisions.

[0003] When the airborne collision avoidance system is in operation, it first transmits an inquiry signal to other aircraft equipped with air traffic control transponders in the airspace, then waits for a period of time and receives the response signals transmitted by the air traffic control transponders of other aircraft in response to the inquiry signal, thus forming a one-to-one "inquiry-response" link between the aircraft and other aircraft. This waiting time is called the receiving decoding window. When the response signals of several consecutive processing cycles meet the distance and altitude related conditions, the airborne collision avoidance system identifies it as an aircraft target, thereby establishing a tracking track.

[0004] In the actual use of the airborne collision avoidance system, its antenna is installed close to the antenna of other L-band devices, and various electronic devices inside the aircraft work in parallel, resulting in increasingly complex electromagnetic signals in the airspace. With the increase in the density of aircraft in the airspace, or the increase in the number of secondary radar inquiries, the number of responses to other aircraft airborne collision avoidance systems or secondary radars in the airspace will also increase. For the aircraft's airborne collision avoidance system, these response signals are all asynchronous response interference signals, and there is a certain probability that the time they arrive at the aircraft will fall within the receiving and decoding window of the aircraft's airborne collision avoidance system. When these asynchronous interference signals meet the target establishment conditions, the aircraft's airborne collision avoidance system will identify them as aircraft targets, thereby establishing a tracking trajectory, resulting in false targets and false alarms, thereby affecting the pilot's understanding and judgment of the airspace situation.

[0005] In order to meet the needs of the next generation of military and civil air traffic control systems and provide aircraft with traffic situation awareness and auxiliary decision-making warning services throughout the entire flight and mission phases, thereby improving pilots' accurate judgment of airspace traffic situations and effectively improving the safety performance of military and civil aircraft flights, it is urgent to study methods to reduce the probability of false targets and false alarms caused by asynchronous response interference signals in the airspace to the aircraft's onboard collision avoidance system. Summary of the invention

[0006] The invention provides a method and a device for reducing asynchronous interference false alarms of an airborne collision avoidance system, so as to reduce asynchronous interference false alarms of the airborne collision avoidance system.

[0007] A first aspect of the present invention provides a method for reducing asynchronous interference false alarms in an airborne collision avoidance system, comprising:

[0008] S1. In the preset direction, the airborne collision avoidance system sends an inquiry request according to the preset period;

[0009] S2, when receiving the response information, if the distance indication corresponding to the response information indicates that the tracking target is not established, determine whether the relationship between the strength of the response information and the preset direction and distance meets the preset relationship; if so, enter S3; if not, enter S6;

[0010] S3. Send a supplementary inquiry request within this period;

[0011] S4. When receiving the response information corresponding to the supplementary inquiry request, determine whether the distance and height of all the response information received in this cycle are within the respective relevant window ranges; if not, enter S6; if yes, enter S5;

[0012] S5. Determine that the response information is valid response information;

[0013] S6. Determine that the response information is asynchronous interference.

[0014] Optionally, after S2 and before S3, the method for reducing asynchronous interference false alarms by the airborne collision avoidance system further includes:

[0015] S30, determine whether the distance corresponding to the response information is less than the minimum protection distance; if so, proceed to S3; if not, proceed to S5.

[0016] Optionally, the minimum protection distance is determined according to the number of established tracking targets.

[0017] Optionally, the minimum protection distance is inversely proportional to the number of established tracking targets.

[0018] Optionally, the preset relationship includes: the strength of the response information decreases as the distance increases;

[0019] The intensity of the response information is within the intensity range corresponding to the preset direction; the intensity value corresponding to the 0° direction is the largest.

[0020] Optionally, send a supplementary inquiry request during this period, including:

[0021] Two additional query requests are sent during this cycle.

[0022] Optionally, determine whether the distance and height of all response messages received in this period are within the respective relevant windows, including:

[0023] It is determined that the difference between the distances and the difference between the heights of all the response messages received in this cycle are within the preset window range.

[0024] A second aspect of the present invention provides a device for reducing asynchronous interference false alarms in an airborne collision avoidance system, which is used to execute the method as described in any one of the first aspects.

[0025] The present invention provides a method and device for reducing asynchronous interference false alarms of an airborne collision avoidance system. According to the difference between a normal response signal and an asynchronous interference response signal, the method filters out the asynchronous interference response signal through a "signal strength-distance" correlation window and increases the method of target confirmation within a minimum distance, thereby reducing the asynchronous interference response signal of the airborne collision avoidance system, establishing a target tracking trajectory, and causing the probability of false targets or false alarms, providing accurate air traffic situation information to pilots, and improving flight safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Design a block diagram for the method of reducing asynchronous interference false alarms for airborne collision avoidance systems;

[0027] Figure 2 This is a schematic diagram of the "Signal Strength-Distance" related window;

[0028] Figure 3 Workflow diagram for confirming the target within the minimum distance. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is by no means limited to any specific settings and methods proposed below, but covers any improvements, replacements and modifications of structures, methods, devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity in the present invention.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0033] The technical solution adopted by the present invention is a method for reducing asynchronous interference false alarms in an airborne collision avoidance system, such as Figure 1 As shown. The method first records the signal strength of the reply signal received by the airborne collision avoidance system of the aircraft, the distance and azimuth from the aircraft to other aircraft, and then trains the relationship between the reply signal strength and distance to obtain the "signal strength-distance" correlation window at different azimuths. Then, during the operation of the airborne collision avoidance system, the "signal strength-distance" correlation window is used to filter the strength of the reply signal received in each monitoring processing cycle and the distance obtained in the ranging algorithm, and the reply signal that does not meet the correlation window is filtered out, and the reply signal that meets the correlation window is sent to the subsequent monitoring and tracking processing flow. In the monitoring and tracking processing flow, the minimum protection distance and the "distance & height" correlation window are set. For other aircraft within the minimum protection distance range, two confirmation processes are added in each monitoring processing cycle. The reply signal that meets the threshold of the "distance & height" correlation window is used to establish the tracking track, and the reply signal that does not meet the threshold of the "distance & height" correlation window is not used in the establishment of the tracking track.

[0034] On the one hand, in the "signal strength-distance" correlation window, it is necessary to consider the different spatial attenuation of signal strength at different orientations of the aircraft and other aircraft. Therefore, it is necessary to establish a "signal strength-distance" correlation window at different orientations within -180° to 180°, with a distance from 0 to the horizontal monitoring distance D, with an orientation resolution of Δφ and a distance resolution of Δd.

[0035] On the other hand, in the process of increasing confirmation within the minimum protection distance, the initial minimum protection distance and the distance-altitude window threshold can be set through external configuration, and the load of the current processing cycle system (that is, the ratio of the task processing time in the current processing cycle to the entire processing cycle) can be monitored in real time. When the system processing load is too high, the minimum protection distance can be reduced. When the system processing load is low, the minimum protection distance can be increased, so as to realize dynamic adjustment of the minimum protection distance without affecting the normal processing function of the airborne collision avoidance system.

[0036] Finally, the reply signal confirmed by the "signal strength-distance" correlation window threshold and the "distance & altitude" correlation window within the minimum protection distance is used to establish the tracking track of the target, establish the target aircraft of the tracking track, and output the target's distance, altitude, azimuth and other information to the external integrated display system.

[0037] Attached Figure 1 A block diagram of the design of an integrated warning method for flight environment monitoring is shown, which includes a "signal strength-distance" correlation window generation unit, a "signal strength-distance" correlation window signal processing unit and a target confirmation unit within a minimum protection distance.

[0038] The "signal strength-distance" correlation window generation unit performs sample training on the "signal strength-distance" correlation model based on the recorded values ​​of the reply signal strength, target relative azimuth, and target relative distance of multiple real target aircraft that have been tracked, and obtains a correlation threshold table of signal strength at different azimuths and different distances between the aircraft and the target aircraft.

[0039] During the operation of the airborne collision avoidance system, after the current processing cycle transmits an inquiry signal to a certain target aircraft, the response signal received in the response receiving and decoding window of the inquiry is sampled for signal strength, target direction finding and target distance finding are performed to obtain the response signal strength sampling value of the target aircraft, the azimuth of the target aircraft relative to the aircraft, and the distance of the target aircraft relative to the aircraft. Then, a corresponding table lookup and comparison judgment is performed in the "signal strength-distance" related window threshold table. The response signal that meets the window threshold is retained and sent to the target confirmation unit within the minimum protection distance for further processing. The response signal that does not meet the window threshold is filtered out.

[0040] The target confirmation unit within the minimum protection distance first receives the externally configured distance & altitude confirmation window and the initial minimum protection distance setting value. In each monitoring distance cycle, it adds several additional inquiries to the target aircraft within the minimum protection distance to obtain the corresponding additional reply signal. Then, according to the distance & altitude window, it performs target confirmation on the reply signal of the current processing cycle. If the reply signals in the current processing cycle are related to each other, they are used to establish the target tracking trajectory. If the reply signals in the current processing cycle are not related to each other, they are not used to establish the target tracking trajectory. The establishment of the target tracking trajectory is carried out in accordance with the same conditions specified in the standards of this professional field. In each monitoring processing cycle, the target confirmation unit within the minimum protection distance will monitor the task processing load of the system in order to achieve dynamic adjustment of the minimum protection distance setting value.

[0041] Attached Figure 2 A specific example of the "signal strength-distance" correlation window threshold table is shown. The figure only gives the threshold window of the relationship between the signal strength and the relative distance at different orientations of the aircraft and the target aircraft, where Δφ represents the orientation resolution; D represents the maximum monitoring range of the airborne collision avoidance system; Δd represents the distance resolution; S(i, j) represents the response signal strength at orientation i and distance j; ΔS(i, j) is the signal strength window threshold at orientation i and distance j.

[0042] Attached Figure 3The workflow of the target confirmation process within the minimum protection distance is shown. Before the airborne collision avoidance system is operated, the distance & height confirmation window threshold and the initial minimum protection distance are set through the external configuration device. During the normal operation of the airborne collision avoidance system, when the reply signal of the target aircraft input by the "signal strength-distance" correlation window signal processing unit is received, the target distance measurement is performed first. If the distance of the target aircraft relative to the aircraft is outside the minimum protection distance, the target tracking trajectory establishment process is directly entered; if the distance of the target aircraft relative to the aircraft is within the minimum protection distance, the target confirmation process is entered. The airborne collision avoidance system performs additional inquiries on the target aircraft in the current cycle and obtains the corresponding additional reply signal. If the reply signal of the current processing cycle does not meet the distance & height correlation threshold, the reply signal of the target in the current cycle is filtered out; if the reply signal of the current processing cycle meets the distance & height correlation threshold, the target aircraft is considered to be a real aircraft, and the reply signal of the target aircraft in the current cycle is sent to the target tracking trajectory establishment process. If the target aircraft's response signals for several consecutive processing cycles meet the target tracking track establishment conditions, the target aircraft's tracking track is established and the target information is output; if the target tracking track establishment conditions are not met, the target tracking track is not established. Finally, the processing load of the entire system in the current cycle is monitored. If the system processing load is higher than the upper threshold, the minimum protection distance setting value is reduced; if the system processing load is lower than the lower threshold, the minimum protection distance setting value is increased; if the system processing load balance is between the upper threshold and the lower threshold, the minimum protection distance setting value of the current cycle is maintained unchanged to ensure that the target confirmation process within the minimum protection distance does not affect the normal function of the airborne collision avoidance system.

[0043] The above description is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which belong to the protection scope of the present invention.

Claims

1. A method for reducing asynchronous interference false alarms in an airborne collision avoidance system, characterized in that: include: S1. In the preset direction, the airborne collision avoidance system sends an inquiry request according to the preset period; S2, when receiving the response information, if the distance indication corresponding to the response information indicates that the tracking target is not established, determine whether the relationship between the strength of the response information and the preset direction and distance meets the preset relationship; if so, enter S3; if not, enter S6; S3. Send a supplementary inquiry request within this period; S4. When receiving the response information corresponding to the supplementary inquiry request, determine whether the distance and height of all the response information received in this cycle are within the respective relevant window ranges; if not, enter S6; if yes, enter S5; S5. Determine that the response information is valid response information; S6. Determine that the response information is asynchronous interference.

2. The method for reducing asynchronous interference false alarms in an airborne collision avoidance system according to claim 1, characterized in that: After S2 and before S3, the method further includes: S30, determine whether the distance corresponding to the response information is less than the minimum protection distance; if so, proceed to S3; if not, proceed to S5.

3. The method for reducing asynchronous interference false alarms in an airborne collision avoidance system according to claim 1, characterized in that: The minimum protection distance is determined according to the number of tracked targets.

4. The method for reducing asynchronous interference false alarms in an airborne collision avoidance system according to claim 1, characterized in that: The minimum protection distance is inversely proportional to the number of tracked targets.

5. The method for reducing asynchronous interference false alarms in an airborne collision avoidance system according to claim 1, characterized in that: The preset relationships include: the strength of the response information decreases as the distance increases; The intensity of the response information is within the intensity range corresponding to the preset direction; the intensity value corresponding to the 0° direction is the largest.

6. The method for reducing asynchronous interference false alarms in an airborne collision avoidance system according to claim 1, characterized in that: Supplementary inquiry requests were sent during this period, including: Two additional query requests are sent during this cycle.

7. The method for reducing asynchronous interference false alarms in an airborne collision avoidance system according to claim 1, characterized in that: Determine whether the distance and height of all response messages received during this cycle are within their respective relevant windows, including: It is determined that the difference between the distances and the difference between the heights of all the response messages received in this cycle are within the preset window range.

8. A device for reducing asynchronous interference false alarms in an airborne collision avoidance system, characterized in that: Used to perform the method according to any one of claims 1 to 7.

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