Method for improving traffic collision avoidance system (TCAS) airspace situation monitoring capability

Abstract

The invention provides a TCAS (Traffic Collision Avoidance System) airspace situation monitoring capability improvement method, which comprises the following steps of: obtaining response of a target aircraft by passively receiving position broadcast of the target aircraft in an airspace and actively inquiring the target aircraft, so as to periodically obtain basic information frames such as distance, height, orientation and the like of the aircraft in the airspace; using the obtained target aircraft information frame to judge whether the target aircraft is in a local aircraft monitoring range, and if the target aircraft accords with the local aircraft monitoring range and an initialization condition, establishing initial tracking for the target aircraft; consistency discrimination is carried out on the target aircrafts which have established initial tracking, and if it is judged that multiple tracking aircrafts belong to the same target aircraft, the tracking aircrafts are reserved and abandoned; and converting the monitoring mode of the target aircraft according to the airspace situation, the data quality and the monitoring capacity condition. And traffic situation awareness enhancement and anti-collision warning services can be provided for the aircraft in operation.

Description

Technical Field

[0001] This invention relates to the field of aircraft communication, navigation, and surveillance technology, and specifically to a method for enhancing TCAS airspace situational surveillance capabilities. Background Technology

[0002] Traffic Collision Avoidance System (TCAS) is an avionics product equipped on aircraft. It monitors aircraft in the airspace by altitude, distance, and bearing, then tracks these target aircraft and assesses their threat level based on their expected flight paths. For aircraft with a potential dangerous approach, it displays and issues voice warnings to the pilots or provides conflict resolution suggestions to prevent dangerous close encounters between aircraft.

[0003] TCAS monitors target aircraft in the airspace in the following ways: it transmits interrogation signals to target aircraft in the airspace using radio frequency signals. Target aircraft equipped with transponders respond after receiving the interrogation. Furthermore, the local TCAS receives the response signal from the target aircraft and obtains the target aircraft's range, bearing, and altitude information frames by measuring and analyzing the response signal. After continuously acquiring the target aircraft's response information frames, it establishes a track monitoring system for tracking the target aircraft's range, bearing, and altitude.

[0004] Existing surveillance methods that employ active interrogation suffer from high power consumption and significant interference with the airspace radio environment. Summary of the Invention

[0005] The purpose of this invention is to provide a method for enhancing TCAS airspace situational awareness capabilities. This method acquires multi-source data on target aircraft within the airspace and calculates the distance, bearing, and altitude of the target aircraft relative to the aircraft itself. This enables the aircraft to provide enhanced traffic situational awareness and collision avoidance warning services for aircraft in operation.

[0006] This invention provides a method for enhancing TCAS airspace situational awareness capabilities, comprising: S1, TCAS periodically acquires passively received information frames and actively interrogated information frames; the information frames include: the distance to the target aircraft. D obj Height difference ΔH obj ,position; S2. Determine whether the target aircraft corresponding to each information frame is within the local monitoring range; if so, when the target aircraft is in the air and its speed is within the preset range, establish tracking for the target aircraft corresponding to each information frame; when the information frame is an active interrogation information frame, establish active track tracking; when the information frame is a passive reception information frame, establish passive track tracking. S3. For a target aircraft that is simultaneously subject to passive track tracking and active track tracking, determine the threat level of the target aircraft based on the information frame, and select passive tracking or active tracking based on the threat level.

[0007] Optionally, the threat level of the target aircraft can be determined based on the information frame, and passive or active tracking can be selected based on the threat level, including: When the signal strength P of the information frame is less than or equal to the trigger threshold M, the threat level of the target machine is determined to be low, passive tracking is retained, and active tracking is discarded. When both conditions are met and When the target aircraft is determined to be of a high threat level, active tracking is retained while passive tracking is abandoned; When P > M is satisfied simultaneously, and When the target aircraft is determined to be of medium threat level, the consistency between active tracking and passive tracking information is assessed. If they are consistent, passive tracking is retained and active tracking is discarded, and the consistency is assessed again after a preset time. If they are inconsistent, active tracking is retained and passive tracking is discarded. If none of the above three conditions are met, the threat level of the target machine in the previous cycle remains unchanged; Among them, information consistency refers to the fact that the difference in distance, height, and orientation between active tracking and passive tracking simultaneously meet their respective preset thresholds. The relative altitude between this aircraft and the target aircraft is s The rate of change of relative height The relative distance is r The rate of change of relative distance .

[0008] Optionally, the trigger threshold M is determined based on the density of target aircraft in the airspace.

[0009] Optionally, after determining the threat level of the target aircraft, the method further includes: The number of current target aircraft at each threat level is determined in descending order of threat level. When the number of current target aircraft at each threat level exceeds the maximum surveillance capacity of the current threat level, the threat level of the target aircraft at the farthest distance in the current threat level is downgraded by one level. Among them, target aircraft with low threat levels will no longer be tracked after being downgraded.

[0010] Optionally, determining whether the target aircraft corresponding to the passively received information frame and the actively interrogated information frame is within the local monitoring range includes: If both conditions are met D obj ≤ D max and ΔHobj ≤ ΔH max If so, it is determined that the target aircraft is within the local surveillance range; in, D max Set the preset monitoring distance for this machine. ΔH max Preset the height monitoring range.

[0011] Optionally, the target aircraft's speed is within a preset range, including both the target aircraft's vertical speed and its relative horizontal speed to the local aircraft.

[0012] Optionally, TCAS periodically acquires passively received information frames, including: TCAS receives the DF17 message broadcast by the target aircraft and parses the DF17 message to obtain the target aircraft's longitude, latitude, altitude, and S-mode address. By combining the longitude, latitude, barometric altitude, and heading information of the aircraft, the distance, bearing, and altitude difference between the target aircraft and the aircraft are calculated.

[0013] Optionally, before establishing tracking for the target aircraft corresponding to each information frame, the method further includes: The positional accuracy of the local navigation data and the quality of the target aircraft DF17 broadcast messages both meet the requirements for passive tracking. Otherwise, establish active track tracking for the target aircraft.

[0014] Optionally, TCAS periodically acquires active query information frames, including: Transmit Mode S interrogation to target aircraft within the airspace, and receive and analyze the target aircraft's response; Based on the target aircraft's response, the distance, bearing, and altitude difference between the target aircraft and the machine are calculated.

[0015] This invention proposes a method for enhancing TCAS (Traffic Situational Monitoring and Surveillance) capabilities in the airspace, which has the following beneficial effects: (1) The present invention uses two methods, passive reception and active inquiry, to acquire the position of the target aircraft in the airspace, and then performs multi-source data fusion to improve the reliability and stability of the TCAS system; (2) The present invention can reduce the active interrogation of target aircraft in the airspace, thereby reducing product power consumption and reducing interference to the airspace radio environment. (3) The present invention optimizes the traditional TCAS monitoring mode, enabling the TCAS system to monitor more aircraft and expand the maximum monitoring range. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the method for enhancing TCAS airspace situational awareness capabilities provided by the present invention. Figure 2 This is a schematic diagram illustrating the threat level of the target aircraft in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0020] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0022] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0024] like Figure 1-2 As shown, the present invention provides a method for improving TCAS airspace situational awareness capabilities, comprising: Step 1: TCAS periodically acquires basic information frames of target aircraft in the airspace through two methods: passively receiving extended message broadcasts from target aircraft in the airspace and actively transmitting interrogations to obtain response data from target aircraft. The basic information frames include: address, range, altitude, and bearing. Step 2: Use the passive received information frame and active interrogation information frame of the target aircraft obtained in Step 1 to determine whether the target aircraft is within the local monitoring range. If it is within the local monitoring range and meets the initialization conditions, then establish passive initial track tracking and active initial track tracking for the target aircraft. Step 3: Perform track consistency verification on the target aircraft for which initial track tracking has been established. If it is determined that the active initial track tracking and the passive initial track tracking are for the same target aircraft, then select the initial track tracking of the target aircraft as the target tracking track. If a target aircraft is only subject to active initial track tracking or only subject to passive initial track tracking, then the active or passive monitoring method will be used directly.

[0025] Step 4: Based on the airspace situation, data quality, and surveillance capacity conditions, switch the surveillance method for the target aircraft.

[0026] The specific implementation steps of passive reception in step 1 above are as follows: Step 1a: TCAS receives the DF17 message broadcast by the target aircraft and parses the DF17 message to obtain the longitude, latitude, altitude, and S-mode transponder address of the target aircraft. Step 1b: Combine the longitude, latitude, barometric altitude, and heading information of the aircraft to calculate the distance, bearing, and altitude difference between the target aircraft and the aircraft.

[0027] The specific implementation steps of the active query in step 1 above are as follows: Step 2a: Send a Mode S interrogation to the target aircraft in the airspace, and receive and parse the target aircraft's response; Step 2b: Based on the target aircraft's response, calculate the distance, bearing, and altitude difference between the target aircraft and the machine.

[0028] The above steps are repeated periodically to periodically acquire basic information frames such as distance, altitude, and bearing of aircraft within the airspace.

[0029] The specific implementation steps of step 2 above are as follows: Step 21: Calculate whether the target aircraft is within the machine's preset monitoring range. Define the machine's preset monitoring distance as... D max The preset height monitoring range is ΔH max Define the actual distance between the target machine and the local machine as... D obj The actual height difference is ΔH obj When the conditions are met simultaneously D obj ≤ D max and ΔH obj ≤ ΔH max At that time, it was assumed that the target aircraft was within the range of the local surveillance system; Step 22: Calculate whether the vertical speed of the target aircraft and its relative horizontal speed to the local aircraft are within the local aircraft's preset speed range. If both are within the local aircraft's preset speed range, then the target aircraft's speed condition is considered to meet the requirements. For example, the vertical speed is calculated by receiving continuous altitude information from the target machine; The relative horizontal speed to the local machine is calculated by receiving continuous position information.

[0030] Step 23: Determine the air-to-ground status of the target aircraft. If the air-to-ground status is in the air, it is considered that the air-to-ground status meets the conditions for establishing initial tracking of the target aircraft. Step 24: If steps 21-23 are satisfied simultaneously, then establish an initial track for the target aircraft.

[0031] The specific implementation steps of step 3 above are as follows: Step 31: Perform address matching on the initial track tracking of the target aircraft. If the addresses of the active initial track tracking and the passive initial track tracking are the same, they are considered to be the same target aircraft. Step 32: Calculate the threat level of the target aircraft, classifying it into low, medium, and high categories. Define the relative altitude between the aircraft and the target aircraft as... s The rate of change of relative height The relative distance is r The rate of change of relative distance Define the signal strength of the broadcast or response received by the local machine from the target machine's DF17 as... P The signal strength trigger threshold for low-threat levels is M .

[0032] When satisfied P ≤ M At that time, the threat level of the target aircraft was low; When both conditions are met and At that time, the target aircraft's threat level was high; When both conditions are met P > M , and At that time, the target aircraft's threat level was medium; Step 33: When the target aircraft threat level is low, retain passive initial track tracking and discard active initial track tracking; when the target aircraft threat level is high, retain active initial track tracking and discard passive initial track tracking; when the target aircraft threat level is medium, verify the consistency of active and passive initial track tracking, and select the tracking type to retain based on the verification result. Furthermore, in step 32 above, if the target machine satisfies any one of the three states of low, medium, or high, then the threat level of the target machine is in a transitional state, remaining unchanged from its original state. Furthermore, in step 33 above, when the target aircraft threat level is medium, the method for selecting active or passive initial trajectory tracking is as follows: Step 331: Calculate the distance difference, altitude difference, and azimuth difference of the active and passive initial track tracking. If the distance difference is ≤290 meters, the altitude difference is ≤100 feet, and the azimuth difference is ≤45 degrees, then the active tracking and passive tracking are considered to have passed the consistency check; otherwise, they are considered to have failed. Step 332: If the consistency check between active tracking and passive tracking fails, then retain active track tracking and discard passive track tracking. Step 333: If the consistency check between active and passive tracking passes, retain passive tracking and discard active tracking. Then, based on the relative altitude, relative distance, and relative speed between the target aircraft and the current aircraft, select... T After a certain period of time, repeat step 331 once more. T The value of T is a positive integer and the range of T is [10, 60] seconds.

[0033] It is understandable that the smaller the relative height, relative distance, and relative speed, the smaller the value of T.

[0034] The specific implementation steps of step 4 above are as follows: Step 41: Calculate the signal strength trigger threshold for low-threat levels based on the density of target aircraft in the airspace. M and update in step 32 M value; It's understandable that increasing aircraft density can raise the trigger threshold. M， Shrink to Figure 2 The threat level circle is shown.

[0035] Step 42: Determine whether the position accuracy of the local navigation data and the quality of the target aircraft DF17 broadcast message meet the requirements of passive tracking. If both conditions are met, select the tracking type according to the judgment conditions in Step 3; otherwise, select the target aircraft monitoring mode as active tracking. Among them, the quality of the target aircraft's DF17 broadcast message refers to the accuracy of the target aircraft's own position and navigation accuracy.

[0036] Step 43, define the maximum surveillance capacity of target aircraft for high, medium, and low threat levels as follows: V H , V M , V L When the number of high-threat target aircraft > V H Then, sort by distance, and reclassify the highest-threat aircraft as medium-threat; if the number of medium-threat target aircraft is greater than [a certain number], [then the classification will be changed to medium-threat]. V M Then, sort by distance, and reclassify the most distant medium-threat aircraft as low-threat; when the number of low-threat target aircraft > V L Then, sort by distance and discard the lowest threat level aircraft that is furthest away.

[0037] Figure 1 This is a diagram illustrating the threat levels of a target aircraft. Based on the threat level of the target aircraft, the threat levels are divided into three categories: low, medium, and high.

[0038] First, calculate whether the target aircraft is within the machine's preset monitoring range, defining the machine's preset monitoring distance as... D max The preset height monitoring range is ΔH max Define the actual distance between the target machine and the local machine as... D obj The actual height difference isΔH obj When the conditions are met simultaneously D obj ≤ D max and ΔH obj ≤ ΔH max The system assumes the target aircraft is within its surveillance range. For target aircraft within its surveillance range, its air-to-ground status is determined. If the aircraft is in the air, tracking is initiated. Then, based on the density of target aircraft in the airspace, the signal strength trigger threshold for low-threat levels is calculated. M and update in step 32 M value.

[0039] Define the relative altitude between the local aircraft and the target aircraft as... s The relative distance is r, and the signal strength received by the local machine from the target machine's DF17 broadcast or response is defined as r. P The signal strength trigger threshold for low-threat levels is M .

[0040] When satisfied P ≤ M At that time, the threat level of the target aircraft is low; when simultaneously meeting the following conditions... and At that time, the target aircraft's threat level was high; when simultaneously meeting the following conditions... P > M , and At that time, the threat level of the target aircraft was medium.

[0041] Finally, the maximum surveillance capacity of target aircraft for high, medium, and low threat levels is defined as follows: V H , V M , V L When the number of high-threat target aircraft > V H Then, sort by distance, and reclassify the highest-threat aircraft as medium-threat; if the number of medium-threat target aircraft is greater than [a certain number], [the classification will be changed to medium-threat]. V M Then, sort by distance, and reclassify the most distant medium-threat aircraft as low-threat; when the number of low-threat target aircraft > V L Then, sort by distance and discard the lowest threat level aircraft that is furthest away.

[0042] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for enhancing TCAS airspace situational awareness capabilities, characterized in that, include: S1. TCAS periodically acquires passively received information frames and actively interrogated information frames; The information frame includes: the distance to the target aircraft. D obj Height difference ΔH obj ,position; S2. Determine whether the target aircraft corresponding to each information frame is within the local monitoring range; if so, when the target aircraft is in the air and its speed is within the preset range, establish tracking for the target aircraft corresponding to each information frame; when the information frame is an active interrogation information frame, establish active track tracking; when the information frame is a passive reception information frame, establish passive track tracking. S3. For a target aircraft that is simultaneously subject to passive track tracking and active track tracking, determine the threat level of the target aircraft based on the information frame, and select passive tracking or active tracking based on the threat level.

2. The method for enhancing TCAS airspace situational awareness capabilities according to claim 1, characterized in that, The threat level of the target aircraft is determined based on the information frame, and passive or active tracking is selected based on the threat level, including: When the signal strength P of the information frame is less than or equal to the trigger threshold M, the threat level of the target machine is determined to be low, passive tracking is retained, and active tracking is discarded. When both conditions are met and When the target aircraft is determined to be of a high threat level, active tracking is retained while passive tracking is abandoned; When P > M is satisfied simultaneously, and When the target aircraft is determined to be of medium threat level, the consistency between active tracking and passive tracking information is assessed. If they are consistent, passive tracking is retained and active tracking is discarded, and the consistency is assessed again after a preset time. If they are inconsistent, active tracking is retained and passive tracking is discarded. If none of the above three conditions are met, the threat level of the target machine in the previous cycle remains unchanged; Among them, information consistency refers to the fact that the difference in distance, height, and orientation between active tracking and passive tracking simultaneously meet their respective preset thresholds. The relative altitude between this aircraft and the target aircraft is s The rate of change of relative height The relative distance is r The rate of change of relative distance .

3. The method for enhancing TCAS airspace situational awareness capabilities according to claim 2, characterized in that, The trigger threshold M is determined based on the density of target aircraft in the airspace.

4. The method for enhancing TCAS airspace situational awareness capabilities according to claim 2, characterized in that, After determining the threat level of the target aircraft, the method further includes: The number of current target aircraft at each threat level is determined in descending order of threat level. When the number of current target aircraft at each threat level exceeds the maximum surveillance capacity of the current threat level, the threat level of the target aircraft at the farthest distance in the current threat level is downgraded by one level. Among them, target aircraft with low threat levels will no longer be tracked after being downgraded.

5. The method for enhancing TCAS airspace situational awareness capabilities according to claim 1, characterized in that, Determining whether the target aircraft corresponding to the passively received information frame and the actively interrogated information frame is within the local monitoring range includes: If both conditions are met D obj ≤ D max and ΔH obj ≤ ΔH max If so, it is determined that the target aircraft is within the local surveillance range; in, D max Set the preset monitoring distance for this machine. ΔH max Preset the height monitoring range.

6. The method for enhancing TCAS airspace situational awareness capabilities according to claim 1, characterized in that, The target aircraft's speed is within the preset range, including both its vertical speed and its relative horizontal speed to the local aircraft.

7. The method for enhancing TCAS airspace situational awareness capabilities according to claim 1, characterized in that, TCAS periodically acquires passively received information frames, including: TCAS receives the DF17 message broadcast by the target aircraft and parses the DF17 message to obtain the target aircraft's longitude, latitude, altitude, and S-mode address. By combining the longitude, latitude, barometric altitude, and heading information of the aircraft, the distance, bearing, and altitude difference between the target aircraft and the aircraft are calculated.

8. The method for enhancing TCAS airspace situational awareness capabilities according to claim 7, characterized in that, Before establishing tracking of the target aircraft corresponding to each information frame, the method further includes: The positional accuracy of the local navigation data and the quality of the target aircraft DF17 broadcast messages both meet the requirements for passive tracking. Otherwise, establish active track tracking for the target aircraft.

9. The method for enhancing TCAS airspace situational awareness capabilities according to claim 1, characterized in that, TCAS periodically acquires active query information frames, including: Transmit Mode S interrogation to target aircraft within the airspace, and receive and analyze the target aircraft's response; Based on the target aircraft's response, the distance, bearing, and altitude difference between the target aircraft and the machine are calculated.

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