Aircraft ADS-B track data association method and system based on speed constraints

Abstract

Aiming at the problem that the point track cannot be associated when the acquired aircraft ADS-B data information is missing (only longitude and latitude data), the present invention discloses an aircraft ADS-B track data association method and system based on speed constraints, introduces the concept of "virtual spherical speed", uses the longitude and latitude data of two adjacent points to calculate the "virtual spherical speed" of the aircraft, and then compares it with the speed limit constraint of civil aircraft to determine whether the two adjacent track points are the same target, and finally proposes a set of screening strategies and processes for distinguishing and associating tracks. Simulation results show that the present invention can quickly distinguish and associate the point tracks of different aircraft, and finally form their respective track information.

Description

Technical Field

[0001] The present invention relates to the technical field of track data processing, and in particular to a method and system for associating aircraft ADS-B track data based on speed constraints. Background Art

[0002] ADS-B stands for Automatic Dependent Surveillance Broadcast, which reports the specific location of the aircraft and the main flight parameters of the current aircraft by sending ADS-B track messages. It is a kind of passive acquisition of flight data. ADS-B sends track messages periodically and spontaneously. The information includes the ICAO number, longitude and latitude, altitude, speed, etc. of the aircraft, which is convenient for the ground control center and other aircraft to monitor the status of the aircraft.

[0003] ADS-B links satellites, aircraft and ground stations together to form an integrated system. The aircraft's location information comes from the global navigation satellite system, and the data is highly accurate and sensitive. In the process of displaying the aircraft's location, the satellite first sends the aircraft's location information to the ADS-B receiver. After receiving the data sent by the satellite, the ADS-B receiver sends a message out through the transmitter. The ground station receives the aircraft message data, decodes it and performs other processing, and finally displays it on the screen in the form of a track. The aircraft's location information will also be transmitted to other aircraft in the airspace, so that other aircraft can understand the aircraft's flight status in a timely manner. At the same time, the aircraft will also receive ADS-B message data sent by other aircraft in the airspace.

[0004] By utilizing the broadcast characteristics of ADS-B, as long as the signal is within the receivable range, the flight data of the aircraft can be received by using the ADS-B receiving equipment on the ground, thereby decoding the track information. By analyzing a large amount of track data, high-value information can be mined. However, sometimes the track data obtained may only have location information such as longitude and latitude due to the lack of information, and it is impossible to determine which target the data points belong to. Summary of the invention

[0005] Aiming at the problem that the point tracks cannot be associated when the acquired aircraft ADS-B data information is missing (only longitude and latitude data), the present invention proposes an aircraft ADS-B track data association method and system based on speed constraint, by introducing the concept of "virtual spherical speed", using the longitude and latitude data of two adjacent points to calculate the "virtual spherical speed" of the aircraft, and then comparing it with the speed limit constraint of civil aircraft to determine whether the two adjacent track points are the same target, and finally proposing a track screening strategy to achieve the association of all track data.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides an aircraft ADS-B track data association method based on speed constraints, comprising:

[0008] The aircraft's "virtual spherical speed" is calculated using the latitude and longitude data of two adjacent points, and then compared with the speed limit constraints of civil aircraft to determine whether the two adjacent track points are the same target.

[0009] Furthermore, the "virtual spherical speed" of the aircraft is calculated as follows:

[0010] According to the conversion relationship between the spherical coordinate system and the rectangular coordinate system

[0011]

[0012] Where r represents the "virtual distance" between the aircraft and the center of the earth, which is the sum of the aircraft's flight altitude and the radius of the earth, and are the longitude and latitude of the track point respectively;

[0013] The "virtual coordinates" (X1, Y1, Z1) and (X2, Y2, Z2) of the three-dimensional space of two adjacent track points in the ADS-B track data of the aircraft with missing information are obtained. According to the cosine theorem of the angle between two vectors, the geocentric angle corresponding to the great circle arc of the two points (X1, Y1, Z1) and (X2, Y2, Z2) is calculated as follows:

[0014]

[0015] where r1 = [X1 Y1 Z1] T , r2=[X2 Y2 Z2] T are the position vectors of the two virtual track points in the geocentric rectangular coordinate system;

[0016] The arc length between the two points (X1, Y1, Z1) and (X2, Y2, Z2) is the product of the geocentric angle and the "virtual distance" between the aircraft and the center of the earth.

[0017] S=rβ

[0018] The aircraft flies at a constant speed between (X1, Y1, Z1) and (X2, Y2, Z2). The "virtual spherical speed" of the aircraft is

[0019]

[0020] Where t1 and t2 represent the time corresponding to two adjacent track points in the ADS-B track data of the aircraft with missing information, and t2 is after t1.

[0021] Furthermore, the method specifically comprises:

[0022] Step 1: Read the time t of the i-th point in the ADS-B track data of the aircraft with missing information i and longitude and latitude

[0023] Step 2, save the i-th point trace data into the file "aircraft j.txt";

[0024] Step 3: Read the time t of the i+1th point i+1 and longitude and latitude

[0025] Step 4, calculate the "virtual spherical speed" of the aircraft between the two points according to the time and longitude and latitude of the last point and the newly read point in "aircraft j.txt";

[0026] Step 5, comparing the calculated "virtual spherical velocity" with twice the speed of sound;

[0027] Step 6, if the "virtual spherical velocity" is less than or equal to twice the speed of sound, then i=i+1, and the i+1th point trace data is stored in the document "aircraft j.txt" in chronological order;

[0028] Step 7, if the "virtual spherical velocity" is greater than twice the speed of sound, the i-th point trace data is stored in the document "other.txt" in chronological order; i=i+1, return to step 3;

[0029] Step 8: If the point trace data has been read and the number of points in the document "other.txt" is greater than 1, the document "other.txt" is re-used as a document to be associated and classified, and the process returns to step 1;

[0030] Step 9: If there is only one dot left in the document "other.txt", the calculation ends.

[0031] Another aspect of the present invention includes an aircraft ADS-B track data association system based on speed constraints, the system being used to:

[0032] The aircraft's "virtual spherical speed" is calculated using the latitude and longitude data of two adjacent points, and then compared with the speed limit constraints of civil aircraft to determine whether the two adjacent track points are the same target.

[0033] Furthermore, the "virtual spherical speed" of the aircraft is calculated as follows:

[0034] According to the conversion relationship between the spherical coordinate system and the rectangular coordinate system

[0035]

[0036] Where r represents the "virtual distance" between the aircraft and the center of the earth, which is the sum of the aircraft's flight altitude and the radius of the earth, and are the longitude and latitude of the track point respectively;

[0037] The "virtual coordinates" (X1, Y1, Z1) and (X2, Y2, Z2) of the three-dimensional space of two adjacent track points in the ADS-B track data of the aircraft with missing information are obtained. According to the cosine theorem of the angle between two vectors, the geocentric angle corresponding to the great circle arc of the two points (X1, Y1, Z1) and (X2, Y2, Z2) is calculated as follows:

[0038]

[0039] where r1 = [X1 Y1 Z1] T , r2=[X2 Y2 Z2] T are the position vectors of the two virtual track points in the geocentric rectangular coordinate system;

[0040] The arc length between the two points (X1, Y1, Z1) and (X2, Y2, Z2) is the product of the geocentric angle and the "virtual distance" between the aircraft and the center of the earth.

[0041] S=rβ

[0042] The aircraft flies at a constant speed between (X1, Y1, Z1) and (X2, Y2, Z2). The "virtual spherical speed" of the aircraft is

[0043]

[0044] Where t1 and t2 represent the time corresponding to two adjacent track points in the ADS-B track data of the aircraft with missing information, and t2 is after t1.

[0045] Furthermore, the system specifically includes:

[0046] The first point track data reading module is used to read the time t of the i-th point track in the ADS-B track data of the aircraft with missing information i and longitude and latitude

[0047] The point trace data storage module is used to store the i-th point trace data into the document "aircraft j.txt";

[0048] The second point trace data reading module is used to read the time t of the i+1th point trace i+1 and longitude and latitude

[0049] The "virtual spherical speed" calculation module is used to calculate the "virtual spherical speed" of the aircraft between two points according to the time and longitude and latitude of the last point and the newly read point in "aircraft j.txt";

[0050] A comparison module, used for comparing the calculated "virtual spherical velocity" with twice the speed of sound;

[0051] The first judgment operation module is used for storing the i+1th point trace data in the document "aircraft j.txt" in chronological order if the "virtual spherical velocity" is less than or equal to twice the speed of sound, then i=i+1;

[0052] The second judgment operation module is used to store the i-th point trace data in the document "other.txt" in chronological order if the "virtual spherical velocity" is greater than twice the speed of sound; i=i+1, and return to the second point trace data reading module;

[0053] The third judgment operation module is used for, if the point trace data is read, and the number of points in the document "other.txt" is greater than 1, then the document "other.txt" is re-used as a document to be associated and classified, and the process returns to the first point trace data reading module;

[0054] The fourth judgment operation module is used to end the calculation if there is only one dot left in the document "other.txt".

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] In order to solve the problem that the track cannot be associated when the information of the acquired aircraft ADS-B data is missing (only longitude and latitude data), the present invention proposes a method and system for associating aircraft ADS-B track data based on speed constraints. By introducing the concept of "virtual spherical speed", the longitude and latitude data of two adjacent points are used to calculate the "virtual spherical speed" of the aircraft, and then by comparing with the speed limit constraint of civil aircraft, it is determined whether the tracks of the two adjacent points are the same target. Finally, a track screening strategy is proposed to achieve the association of all track data. By performing an association analysis on ADS-B data with missing information, the results show that the present invention can effectively associate and classify different track points and form effective track information of different aircraft, indicating that the present invention is effective and accurate in dealing with the above problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 An example diagram of the positions of two adjacent points on a virtual sphere according to an embodiment of the present invention;

[0058] Figure 2 This is a flow chart of a track association segmentation strategy based on one-by-one screening according to an embodiment of the present invention;

[0059] Figure 3This is an example diagram of ADS-B data with missing information in an embodiment of the present invention;

[0060] Figure 4 This is an example diagram of the virtual spherical velocity between two adjacent points according to an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of track association screening results according to an embodiment of the present invention;

[0062] Figure 6 The present invention is a schematic diagram of an architecture of an aircraft ADS-B track data association system based on speed constraints. DETAILED DESCRIPTION

[0063] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments:

[0064] An aircraft ADS-B track data association method based on speed constraints, comprising:

[0065] The "virtual spherical speed" of the aircraft is calculated using the longitude and latitude data of two adjacent points. Then, by comparing it with the speed limit constraint of civil aircraft, it is determined whether the tracks of the two adjacent points are the same target. Finally, a track screening strategy is proposed to achieve the association of all track data.

[0066] The method specifically includes:

[0067] 1) Point trace identity judgment based on “virtual spherical velocity”

[0068] For targets moving in three-dimensional space, if only their latitude and longitude information is known (i.e., the three-dimensional coordinates lack one-dimensional altitude), it is usually impossible to obtain their speed information through differentiation. However, considering that the received ADS-B data is the track data of civil aircraft, most of them are in constant altitude cruising flight state. According to the prior information of the usual cruising altitude of civil aircraft, it can be assumed that the aircraft are flying on a sphere with an altitude of about 8000m. At this time, the two-dimensional coordinate information of the target can be completed, and then the average speed between the two points can be calculated through the three-dimensional coordinates of the two points on the sphere through the assumption of uniform motion. This is the average speed of the aircraft in a virtual or hypothetical sphere, so it is defined as "virtual spherical speed". The calculation method of virtual spherical speed is as follows, such as Figure 1 As shown, assuming that the longitude and latitude data of two adjacent points are obtained: the data at time t1 is The data at time t2 is

[0069] Due to the lack of altitude information, it is actually impossible to obtain accurate three-dimensional spatial position information of the aircraft. For this reason, it is assumed that the aircraft flies on a sphere with an altitude of 8000m, and the earth is also a sphere with a radius of about 6371000m. The "virtual distance" between the aircraft and the center of the earth is r = 6379000m. According to the conversion relationship between the spherical coordinate system and the rectangular coordinate system

[0070]

[0071] Where λ and are the longitude and latitude of the track point respectively.

[0072] The "virtual coordinates" (X1, Y1, Z1) and (X2, Y2, Z2) of each track point in three-dimensional space can be obtained. With the coordinates of two points, according to the cosine theorem of the angle between two vectors, the geocentric angle corresponding to the great circle passing through the two points (i.e. (X1, Y1, Z1) and (X2, Y2, Z2)) can be calculated as

[0073]

[0074] Where r1=[X1 Y1 Z1] T , r2=[X2 Y2 Z2] T are the position vectors of the two virtual track points in the geocentric rectangular coordinate system;

[0075] The length of the arc between the two points is the product of the geocentric angle and the radius of the virtual sphere (i.e. the virtual distance between the aircraft and the center of the earth).

[0076] S=rβ (3)

[0077] If these two points correspond to the same aircraft, and the aircraft flies at a constant speed between the two points, then the "virtual spherical speed" of the aircraft is

[0078]

[0079] Where t1 and t2 represent the time corresponding to two adjacent track points in the ADS-B track data of the aircraft with missing information, and t2 is after t1.

[0080] For civil aircraft, the speed is usually less than the speed of sound V S =340 (m / s), considering the possible deviation of latitude and longitude data, a civil aircraft speed limit is defined (twice the speed of sound 2V S ), it is believed that the speed data of civil aircraft cannot exceed this value, so the following association strategy is set

[0081]

[0082] If the calculated "virtual spherical speed" of the aircraft is less than the speed limit of civil aviation aircraft, it means that the aircraft has the ability to fly from the first point to the second point during the period, so these two points may be two point traces of the same aircraft; if the calculated "virtual spherical speed" of the aircraft is greater than the speed limit of civil aviation aircraft, it means that the aircraft obviously does not have the ability to fly from the first point to the second point during the period, so these two points are definitely not two point traces of the same aircraft.

[0083] 2) Track association segmentation based on one-by-one screening

[0084] The previous section studied how to determine whether two adjacent points are the track of the same aircraft. However, in practice, a batch of ADS-B data usually contains hundreds or even thousands of points. This requires the design of a screening and association strategy to identify all the tracks belonging to the same aircraft and merge them together to form a continuous track. To this end, this section proposes a point-by-point screening and line-by-line extraction track association strategy.

[0085] After obtaining a batch of longitude and latitude point sequences that change with time, the point identity judgment method based on the "virtual spherical velocity" mentioned in the previous section can be used to filter out the point data belonging to the same aircraft one by one and form their own track data. The specific screening strategy and process are as follows:

[0086] (1) Read the time t of the i-th (i=1, 2, 3, ...) point trace i and longitude and latitude

[0087] (2) Store the i-th point trace data into the file “aircraft j (j = 1, 2, 3, ...).txt”;

[0088] (3) Read the time t of the i+1th point trace i+1 and longitude and latitude

[0089] (4) Calculate the "virtual spherical speed" between the two points based on the time and longitude and latitude of the last point and the newly read point in "aircraft j.txt";

[0090] (5) Compare the calculated “virtual spherical velocity” with twice the speed of sound;

[0091] (6) If the "virtual spherical velocity" is less than or equal to twice the speed of sound, then i=i+1, and return to step (2) (i.e., store the i+1th point trace data in the file "aircraft j.txt" in chronological order);

[0092] (7) If the "virtual spherical velocity" is greater than twice the speed of sound, the i-th point trace data is stored in the document "other.txt" in chronological order; i = i + 1, and return to step (3);

[0093] (8) If the point trace data has been read and the number of points in the document "other.txt" is greater than 1, the document "other.txt" is re-used as the document to be associated and classified, and the process returns to step (1);

[0094] (9) If there is only one dot left in the document "other.txt", the calculation ends.

[0095] The specific flow chart is as follows Figure 2 shown.

[0096] According to the above process, and combined with the calculation method of "virtual spherical speed", when a batch of ADS-B data with missing information is obtained, the point tracks belonging to a certain numbered aircraft can be associated and identified and combined into the continuous track of the aircraft, and the aircraft track can be extracted from the original data one by one. Finally, the original data can be divided into several deterministic continuous tracks belonging to aircraft with different numbers.

[0097] In order to verify the effect of the present invention, the following simulation analysis is performed:

[0098] A batch of ADS-B data with missing information is selected, with a total of 221 points, and the information obtained includes time, longitude and latitude information. The longitude and latitude points are distributed in a two-dimensional plane as follows Figure 3 As shown, intuitively, this batch of data should contain the track information of several aircraft, but whether the relatively close tracks belong to the same aircraft still needs quantitative analysis. The algorithm of the present invention is used to perform association analysis on this batch of data to verify the effectiveness of the algorithm of the present invention.

[0099] First, calculate the "virtual spherical velocity" between two adjacent points in sequence, such as Figure 4 As shown. It can be seen that when two adjacent points may be the track information of the same aircraft, the value of the virtual spherical velocity calculation is usually less than 600m / s, and when the two adjacent points are not the track information of the same aircraft, the value of the virtual spherical velocity calculation increases significantly, up to the order of 100000m / s, which is not only far beyond the limit of civil aircraft, but also more than ten times the first cosmic speed. At present, no aircraft can reach this speed. Therefore, it can be determined that the two adjacent points are not the track of the same aircraft, but the calculated "virtual spherical velocity" is too large because the distance between the two points belonging to different aircraft tracks is too far.

[0100] The track association screening strategy proposed in this invention is used to analyze the example, and the recognition results obtained are as follows: Figure 5 shown.

[0101] It can be seen that through the association screening of the algorithm of the present invention, the batch of ADS-B data is finally identified as the tracks of three aircraft. The first aircraft is in the northernmost part, flying from the east to the west, then turning east and flying west again (i.e., the dot track sequence marked with "o" in the figure); the second aircraft is in the south of the first aircraft, flying from the northeast to the southwest (i.e., the dot track sequence marked with "◇" in the figure); the third aircraft is far away from the first two aircraft, in the southwest direction, flying in the southwest direction (i.e., the dot track sequence marked with "☆" in the figure). The analysis results are basically consistent with the intuitive judgment, thus proving the effectiveness and accuracy of the algorithm of the present invention. It should be pointed out that the conclusion that the algorithm of the present invention judges that it is the track of the same aircraft is only considered from the perspective of flight speed performance constraints. Whether it is indeed the dot track of the same aircraft in the end, more information is needed to support the judgment.

[0102] On the basis of the above embodiments, the present invention further proposes an aircraft ADS-B track data association system based on speed constraints, which is used for:

[0103] The aircraft's "virtual spherical speed" is calculated using the latitude and longitude data of two adjacent points, and then compared with the speed limit constraints of civil aircraft to determine whether the two adjacent track points are the same target.

[0104] Furthermore, the "virtual spherical speed" of the aircraft is calculated as follows:

[0105] According to the conversion relationship between the spherical coordinate system and the rectangular coordinate system

[0106]

[0107] Where r represents the "virtual distance" between the aircraft and the center of the earth, which is the sum of the aircraft's flight altitude and the radius of the earth, and are the longitude and latitude of the track point respectively;

[0108] The "virtual coordinates" (X1, Y1, Z1) and (X2, Y2, Z2) of the three-dimensional space of two adjacent track points in the ADS-B track data of the aircraft with missing information are obtained. According to the cosine theorem of the angle between two vectors, the geocentric angle corresponding to the great circle arc of the two points (X1, Y1, Z1) and (X2, Y2, Z2) is calculated as follows:

[0109]

[0110] where r1 = [X1 Y1 Z1] T , r2=[X2 Y2 Z2] T are the position vectors of the two virtual track points in the geocentric rectangular coordinate system;

[0111] The arc length between the two points (X1, Y1, Z1) and (X2, Y2, Z2) is the product of the geocentric angle and the "virtual distance" between the aircraft and the center of the earth.

[0112] S=rβ

[0113] The aircraft flies at a constant speed between (X1, Y1, Z1) and (X2, Y2, Z2). The "virtual spherical speed" of the aircraft is

[0114]

[0115] Where t1 and t2 represent the time corresponding to two adjacent track points in the ADS-B track data of the aircraft with missing information, and t2 is after t1.

[0116] Furthermore, if Figure 6 As shown, the system specifically includes:

[0117] The first point track data reading module is used to read the time t of the i-th point track in the ADS-B track data of the aircraft with missing information i and longitude and latitude

[0118] The point trace data storage module is used to store the i-th point trace data into the document "aircraft j.txt";

[0119] The second point trace data reading module is used to read the time t of the i+1th point trace i+1 and longitude and latitude

[0120] The "virtual spherical speed" calculation module is used to calculate the "virtual spherical speed" of the aircraft between two points according to the time and longitude and latitude of the last point and the newly read point in "aircraft j.txt";

[0121] A comparison module, used for comparing the calculated "virtual spherical velocity" with twice the speed of sound;

[0122] The first judgment operation module is used for storing the i+1th point trace data in the document "aircraft j.txt" in chronological order if the "virtual spherical velocity" is less than or equal to twice the speed of sound, then i=i+1;

[0123] The second judgment operation module is used to store the i-th point trace data in the document "other.txt" in chronological order if the "virtual spherical velocity" is greater than twice the speed of sound; i=i+1, and return to the second point trace data reading module;

[0124] The third judgment operation module is used for, if the point trace data is read, and the number of points in the document "other.txt" is greater than 1, then the document "other.txt" is re-used as a document to be associated and classified, and the process returns to the first point trace data reading module;

[0125] The fourth judgment operation module is used to end the calculation if there is only one dot left in the document "other.txt".

[0126] In summary, when ADS-B data of aircraft with missing information (only longitude and latitude data) is obtained, it is necessary to associate each point track data to determine the attribute information. For this purpose, the present invention proposes a method for judging the identity of two adjacent points based on "virtual spherical speed" and a track association segmentation strategy for screening one by one, and uses the present invention to perform association analysis on a batch of ADS-B data with missing information. The results show that different point tracks can be effectively associated and classified, and effective track information of different aircraft can be formed, which shows that the present invention is effective and accurate in dealing with the above-mentioned problems. On the basis of the recognition results of the present invention, other information can be further used for verification and confirmation.

[0127] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for associating aircraft ADS-B track data based on speed constraints, characterized in that: include: The "virtual spherical speed" of the aircraft is calculated using the longitude and latitude data of two adjacent points, and then compared with the speed limit constraint of civil aircraft to determine whether the two adjacent track points are the same target; The "virtual spherical speed" of the aircraft is calculated as follows: According to the conversion relationship between the spherical coordinate system and the rectangular coordinate system Where r represents the "virtual distance" between the aircraft and the center of the earth, which is the sum of the aircraft's flight altitude and the radius of the earth, and are the longitude and latitude of the track point respectively; The "virtual coordinates" (X1, Y1, Z1) and (X2, Y2, Z2) of the three-dimensional space of two adjacent track points in the ADS-B track data of the aircraft with missing information are obtained. According to the cosine theorem of the angle between two vectors, the geocentric angle corresponding to the great circle arc of the two points (X1, Y1, Z1) and (X2, Y2, Z2) is calculated as follows: where r1 = [X1 Y1 Z1] T , r2=[X2 Y2 Z2] T are the position vectors of two virtual track points in the geocentric rectangular coordinate system; The arc length between the two points (X1, Y1, Z1) and (X2, Y2, Z2) is the product of the geocentric angle and the "virtual distance" between the aircraft and the center of the earth. S＝rβ The aircraft flies at a constant speed between (X1, Y1, Z1) and (X2, Y2, Z2). The "virtual spherical speed" of the aircraft is Where t1 and t2 represent the time corresponding to two adjacent track points in the ADS-B track data of the aircraft with missing information, and t2 is after t1; The method specifically includes: Step 1: Read the time t of the i-th point in the ADS-B track data of the aircraft with missing information i and longitude and latitude Step 2, save the i-th point trace data into the file "aircraft j.txt"; Step 3: Read the time t of the i+1th point i+1 and longitude and latitude Step 4, calculate the "virtual spherical speed" of the aircraft between the two points according to the time and longitude and latitude of the last point and the newly read point in "aircraft j.txt"; Step 5, comparing the calculated "virtual spherical velocity" with twice the speed of sound; Step 6, if the "virtual spherical velocity" is less than or equal to twice the speed of sound, then i=i+1, and the i+1th point trace data is stored in the document "aircraft j.txt" in chronological order; Step 7, if the "virtual spherical velocity" is greater than twice the speed of sound, the i-th point trace data is stored in the document "other.txt" in chronological order; i=i+1, return to step 3; Step 8: If the point trace data is read, and the number of points in the document "other.txt" is greater than 1, the document "other.txt" is re-used as a document to be associated and classified, and the process returns to step 1; Step 9: If there is only one dot left in the document "other.txt", the calculation ends.

2. An aircraft ADS-B track data association system based on speed constraints, characterized in that: The system is used to: The "virtual spherical speed" of the aircraft is calculated using the longitude and latitude data of two adjacent points, and then compared with the speed limit constraint of civil aircraft to determine whether the two adjacent track points are the same target; The "virtual spherical speed" of the aircraft is calculated as follows: According to the conversion relationship between the spherical coordinate system and the rectangular coordinate system Where r represents the "virtual distance" between the aircraft and the center of the earth, which is the sum of the aircraft's flight altitude and the radius of the earth, and are the longitude and latitude of the track point respectively; The "virtual coordinates" (X1, Y1, Z1) and (X2, Y2, Z2) of the three-dimensional space of two adjacent track points in the ADS-B track data of the aircraft with missing information are obtained. According to the cosine theorem of the angle between two vectors, the geocentric angle corresponding to the great circle arc of the two points (X1, Y1, Z1) and (X2, Y2, Z2) is calculated as follows: where r1 = [X1 Y1 Z1] T , r2=[X2 Y2 Z2] T are the position vectors of two virtual track points in the geocentric rectangular coordinate system; The arc length between the two points (X1, Y1, Z1) and (X2, Y2, Z2) is the product of the geocentric angle and the "virtual distance" between the aircraft and the center of the earth. S＝rβ The aircraft flies at a constant speed between (X1, Y1, Z1) and (X2, Y2, Z2). The "virtual spherical speed" of the aircraft is Where t1 and t2 represent the time corresponding to two adjacent track points in the ADS-B track data of the aircraft with missing information, and t2 is after t1; The system specifically includes: The first point track data reading module is used to read the time t of the i-th point track in the ADS-B track data of the aircraft with missing information i and longitude and latitude Point trace data storage module, used to store the i-th point trace data into the document "aircraft j.txt"; The second point trace data reading module is used to read the time t of the i+1th point trace i+1 and longitude and latitude The "virtual spherical speed" calculation module is used to calculate the "virtual spherical speed" of the aircraft between two points according to the time and longitude and latitude of the last point and the newly read point in "aircraft j.txt"; A comparison module, used for comparing the calculated "virtual spherical velocity" with twice the speed of sound; The first judgment operation module is used for storing the i+1th point trace data in the document "aircraft j.txt" in chronological order if the "virtual spherical velocity" is less than or equal to twice the speed of sound, then i=i+1; The second judgment operation module is used to store the i-th point trace data in the document "other.txt" in chronological order if the "virtual spherical velocity" is greater than twice the speed of sound; i=i+1, and return to the second point trace data reading module; The third judgment operation module is used for, if the point trace data is read, and the number of points in the document "other.txt" is greater than 1, then the document "other.txt" is re-used as a document to be associated and classified, and the first point trace data reading module is returned; The fourth judgment operation module is used to end the calculation if there is only one dot left in the document "other.txt".

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