An ADS-B false target identification method

Abstract

The application belongs to the technical field of avionics, and discloses an ADS-B false target identification method. Statistical analysis is carried out based on ADS-B self information, and operation is carried out in combination with some other features of the received information; the method can be upgraded without additional hardware, and can automatically realize evaluation on the reality of the air ADS-B target; the method does not depend on secondary radar for identification, and can meet the application of small airplanes equipped with ADS-B IN.

Description

Technical Field

[0001] This invention belongs to the technical field of avionics, and in particular relates to an ADS-B false target identification method. Background Technology

[0002] During air traffic control surveillance, ADS-B OUT transmitter modules are widely installed on civil aircraft and drones due to their low cost, small size, and simple manufacturing. However, many criminals also exploit the characteristics of ADS-B OUT to set up numerous false ADS-B targets, severely impacting both airborne aircraft and ground-based air traffic control surveillance. Ground-based air traffic control stations typically rely on multiple base stations to collaboratively identify false targets, thus increasing the cost of ground-based air traffic control surveillance. Furthermore, aircraft in flight cannot effectively identify false targets. Summary of the Invention

[0003] The purpose of this invention is to design an ADS-B false target identification method for situations where no secondary radar is involved and no additional ground monitoring station is required.

[0004] To achieve the above objectives, the present invention employs the following technical solution.

[0005] S1 receives ADS-B airborne location messages, speed messages, identity information, status information, etc.

[0006] S2, analyze the target's position L0, velocity V0, power P0, and azimuth B0 in the current period, where position L0 is composed of longitude, latitude, and altitude;

[0007] S3, using L0 and the current reference position L (the machine's position, composed of longitude, latitude, altitude, etc.), calculate the current relative bearing B. j The distance is R.

[0008] S4, when R is greater than the threshold value, calculate the azimuth deviation ΔB = abs(B0 - B). j If ΔB is less than the threshold value, then B f0 =TRUE, otherwise B f0 =FALSE, when R is less than or equal to the threshold value, B f0 =TRUE.

[0009] S5, calculate the predicted L for the next time step based on L0 and V0. est At the same time, according to L est Calculate B with L0 est Calculate P based on the change of R. est value.

[0010] S6 receives the next-moment ADS-B airborne position message, speed message, identity information, status information, etc.

[0011] S7, analyze the target's position L1, velocity V1, power P1, and azimuth B1 in the current cycle;

[0012] S8, When R is greater than the threshold value, calculate ΔB = abs(B1 - B). est If ΔB is less than the threshold value, then B f1 =TRUE, otherwise B f1 =FALSE, when R is less than or equal to the threshold value, B f1 =TRUE.

[0013] S9, calculate ΔL = abs(L1 - L) est If ΔL is less than the threshold value, then L f1 =TRUE, otherwise L f1 =FALSE, (Note that the L here is composed of longitude, latitude, altitude and other information).

[0014] S10, calculate ΔP = abs(P1 - P est If ΔP is less than the threshold value, then P f1 =TRUE, otherwise P f1 =FALSE, (Note that the L here is composed of longitude, latitude, altitude and other information).

[0015] S11, correct the current values ​​of L1, V1, P1, and B1, L1 = α1 × L1 + β1 × L est V1 = α1 × V1 + β1 × V est P1 = α1 × P1 + β1 × P est B1 = α1 × B1 + β1 × B est ;

[0016] S12, execute steps S6 to S11 n times to obtain {B} f0 B f1 ······B fn}, {L f1 L f1 ·····L fn}, {P f1 P f1 ·····P fn The probability that orientation B is incorrect is B. fp The probability of an error in calculating the power P is P. fp The probability of an incorrect position L is calculated as L. fp ,

[0017] S13, calculate the probability that the target is a false target: Error = a × B fp +b×L fp +c×P fp ;

[0018] S14. When Error > δ, the confidence level of the target being a false target is high; otherwise, it is low.

[0019] S15, repeat S12 to S14;

[0020] S16, program ends.

[0021] The advantages and effects of this invention can be:

[0022] The algorithm performs statistical analysis based on ADS-B information and combines it with other features of the received information for computation. It is versatile and suitable for various applications, such as aerial targets and ground air traffic control stations. It can be upgraded without additional hardware and automatically assesses the authenticity of aerial ADS-B targets. This algorithm does not rely on secondary radar for identification and can meet the needs of small aircraft equipped with ADS-B IN. The signal receiving device is singular, eliminating the need for synchronization between multiple devices or compensation for signal time differences. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an ADS-B false target identification method. Detailed Implementation

[0024] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] This invention provides an ADS-B false target identification method, such as... Figure 1 As shown, it includes:

[0026] S1 receives ADS-B airborne location messages, speed messages, identity information, status information, etc.

[0027] S2, using the CPR concise location report algorithm, calculates the target's current position L0 (latitude L) for the current period. lat0 Longitude L lon0 Based on the ADS-B message structure and the protocol specified in the RTCA DO-260 standard, the speed V0 (eastbound speed V) is parsed out. E0 Northbound speed V N0 Horizontal velocity V U0 Altitude Alt0, Power P0 = (Total power received from the target in the current period) / Number of times the target was received in the current period, Azimuth B0;

[0028] S3, calculate the current relative azimuth B using the received position L0 and the current reference position L. j The distance is R. First, project the two latitude and longitude signals onto a plane with the current reference position L as the origin, and calculate the values ​​of x and y. That is, R = sqrt(x... 2 +y 2 +(Alt own -Alt0) 2 When x is not 0, B j =arctan(y / x), and then determine the quadrant based on the signs of x and y, correcting B. j The value of .

[0029] S4, when R is greater than 1000m and less than 5000m, calculate ΔB = abs(B0 - B j If ΔB is less than 5°, then B f0 =TRUE, otherwise B f0 =FALSE, when R is less than or equal to the threshold value, B f0 =TRUE, when R is greater than 5000m and less than 10000m, if ΔB is less than 2°, then B f0 =TRUE, otherwise B f0 =FALSE, when R is greater than 10000m, if ΔB is less than 1°, then B f0 =TRUE, otherwise B f0 =FALSE.

[0030] S5, calculate L at the next moment based on L0 and V0. est At the same time, according to L est Calculate B with L0 est The calculation method is the same as in S3, and L is calculated simultaneously. est The distance R between L0 and L0 est ΔR=RR est Calculate P based on the change of R. est Value, = P0 - C × (ΔR) 3 +δ, where C and δ are constants.

[0031] S6 receives the next-moment ADS-B airborne position message, speed message, identity information, status information, etc.

[0032] S7, analyze the target's position L1, velocity V1, power P1, and azimuth B1 in the current cycle;

[0033] S8, when R is greater than 1000m and less than 5000m, calculate ΔB = abs(B1 - B). j If ΔB is less than 5°, then B f1 =TRUE, otherwise Bf1 =FALSE, when R is less than or equal to the threshold value, B f1 =TRUE, when R is greater than 5000m and less than 10000m, if ΔB is less than 2°, then B f1 =TRUE, otherwise B f1 =FALSE, when R is greater than 10000m, if ΔB is less than 1°, then B f1 =TRUE, otherwise B f1 =FALSE.

[0034] S9, calculate ΔL=abs(L1-L est If the latitude value error is <0.00027°, then L flat1 =TRUE, otherwise L flat1 =FALSE, when the latitude is -1° to 1°, if the longitude error is <0.00027°, then L flon1 =TRUE, otherwise L flon1 =FALSE, when the latitude value is 1°~87° or -87°~-1°, if the longitude value error is <0.00054°, then L flon1 =TRUE, otherwise L flon1 =FALSE, when the latitude value is 87°~90° or -90°~-87°, if the longitude value error is <0.001°, then L flon1 =TRUE, otherwise L flon1 =FALSE, when L flat1 and L flon1 When both are TRUE, L f1 If TRUE, then FALSE.

[0035] S10, calculate ΔP = abs(P1 - P est If ΔP is less than the threshold value, then P f1 =TRUE, otherwise P f1 =FALSE.

[0036] S11, correct the current values ​​of L1, V1, P1, B1, L1 = 0.831 × L1 + 0.17 × L est V1 = 0.88 × V1 + 0.12 × V est P1 = 0.5 × P1 + 0.5 × P est When R is in [0, 1000], B1 = B1; when R is in [1000, ∞], B1 = 0.7 × B1 + 0.3 × B est ;

[0037] S12, execute steps S6 to S11 n times to obtain {B} f0 B f1 ······Bfn}, {L f1 L f1 ·····L fn}, {P f1 P f1 ·····P fn Set True = 1 and 0 = false. Calculate the probability that the orientation B is incorrect as B. fp = (n+1-B f0 -B f1 -·····B fn The probability of calculating the power P incorrectly is P(n+1) / (n+1). fp =(nP f1 -P f2 -····-P fn The probability of position L being incorrect is calculated as Lfp = (nL) / n. f1 -L f2 -····-L fn ) / n,

[0038] S13, calculate the probability that the target is a false target: Error = 0.3 × B fp +0.48×L fp +0.22×P fp ;

[0039] S14. When Error > 0.5, the confidence level of the target being a false target is high; otherwise, it is low.

[0040] S15, repeat S12 to S14;

[0041] S16, program ends.

[0042] The technical solution of this invention is based on statistical analysis of ADS-B information and combined with other features of the received information for calculation. The algorithm is universal and suitable for different types of applications, such as aerial targets and ground air traffic control stations. It can be upgraded without adding additional hardware and can automatically evaluate the authenticity of aerial ADS-B targets. This algorithm does not rely on secondary radar for identification and can meet the application requirements of small aircraft equipped with ADS-B IN. The signal receiving device is singular and does not require synchronization between multiple devices or compensation for signal time differences.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. An ADS-B method for identifying false targets, characterized in that, The method includes: At times S1 and T0, acquire the local reference position, as well as the air position, speed, identity, and status information of the airborne ADS-B target; and parse the airborne ADS-B target's position L0, speed V0, power P0, and the relative bearing B0 and distance R0 between the local unit and the airborne ADS-B target. S2, calculate the estimated position L of the ADS-B target at time T1 based on the target's position L0 and velocity V0. est1 According to L est1 The azimuth estimate B is calculated using L0. est1 The estimated power P is calculated based on the change in distance R0. est1 value; At times S3 and T1, acquire the local reference position, as well as the airborne position, speed, identity, and status information of the airborne ADS-B target; and parse the airborne ADS-B target's position L1, speed V1, power P1, and bearing B1; as well as the relative bearing B1 and distance R1 between the local unit and the airborne ADS-B target. S4, based on the location estimate L est Predicted azimuth value B est Power estimate P est And position L1, azimuth B1, power P1, and a flag indicating an incorrect position calculation L. f1 The sign of incorrect orientation B f1 Power error flag P f1 Correct the values ​​of position L1, velocity V1, power P1, and azimuth B1 at time T1. S5, based on the ADS-B target's position L1 and velocity V1 at time T1, calculate the estimated position L of the ADS-B target at time T2. est2 According to L est2 The azimuth estimate B is calculated using L1. est2 The estimated power P is calculated based on the change in distance R1. est2 value; S6, calculate the position error flag L corresponding to times T2, ..., Tn according to the method of steps S3-S5. f2 ·····L fn The sign of incorrect orientation B f2 ······B fn Power error flag P f2 ·····P fn ; S7, based on the position error flag L from time T1 to time Tn. f1 ·····L fn B f1 ······B fn Power error flag P f1 ·····P fn The probability of the orientation B being incorrect is calculated as B. fp The probability of an error in calculating the power P is P. fp The probability of an incorrect position L is calculated as L. fp ; S8, the probability of orientation B being incorrect is B. fp The probability of an error in power P is P. fp The probability of position L being incorrect is L fp Calculate the probability that the airborne ADS-B target is a false target. If the probability that the airborne ADS-B target is a false target is greater than a preset value, then it is determined to be a false target.

2. The ADS-B false target identification method according to claim 1, characterized in that, In S1, the specific steps for parsing the position L0, velocity V0, and power P0 of an airborne ADS-B target are as follows: The position L0 of the airborne ADS-B target is calculated using the CPR concise position report algorithm, and the velocity V0 and altitude Alt0 are parsed according to the ADS-B message structure and protocol. Power P0 = (total power received from the target in the current period) / number of times the target is received in the current period.

3. The ADS-B false target identification method according to claim 1, characterized in that, In S1, the relative bearing B0 between the aircraft and the airborne ADS-B target is as follows: The position of the aerial ADS-B target is projected onto a plane with the origin L of the pilot's position. The x and y values ​​of the projected aerial ADS-B target are calculated, and R = sqrt(x) is calculated. 2 +y 2 +(Alt own -Alt0) 2 When x is not 0, B0 = arctan(y / x). Then, based on the signs of x and y, the quadrant is determined, and the value of B0 is corrected. Alt own This is the machine's height.

4. The ADS-B false target identification method according to claim 1, characterized in that, S2 specifically refers to: The estimated position L at time T1 is calculated based on L0 and V0. est Meanwhile, based on the location estimate L est The azimuth estimate B is calculated using L0. est Calculate the location estimate L est The distance R between L0 and L0 est ΔR = R - R est The power estimate P is calculated based on ΔR. est Value, P est =P0-C×(ΔR) 3 +δ, where C and δ are constants.

5. The ADS-B false target identification method according to claim 1, characterized in that, In S4, the flag L indicating a positional error is calculated. f1 The sign of incorrect orientation B f1 Power error flag P f1 Specifically: When R is greater than the threshold value, calculate ΔB = abs(B1 - B). est If ΔB is less than the threshold value, then B f1 =TRUE, otherwise B f1 =FALSE, when R is less than or equal to the threshold value, B f1 =TRUE; Calculate ΔL = abs(L1 - L) est If ΔL is less than the threshold value, then L f1 =TRUE, otherwise L f1 =FALSE; Calculate ΔP = abs(P1 - P) est If ΔP is less than the threshold value, then P f1 =TRUE, otherwise P f1 =FALSE.

6. The ADS-B false target identification method according to claim 1, characterized in that, In S4, the values ​​of position L1, velocity V1, power P1, and orientation B1 at time T1 are specifically corrected as follows: L1=α1×L1+β1×L est ; V1=α1×V1+β1×V est ; P1=α1×P1+β1×P est ; B1=α1×B1+β1×B est 。 7. The ADS-B false target identification method according to claim 1, characterized in that, In S7, the probability of the orientation B being incorrect is calculated as B. fp The probability of an error in calculating the power P is P. fp The probability of an incorrect position L is calculated as L. fp Specifically, the mean of the azimuth error flags at n time points is used as the probability of azimuth B being incorrect. Calculate the mean of the power error flags at n time points as the probability of power P error; Calculate the mean of the position error flags at n time points as the probability of position L being incorrect.

8. The ADS-B false target identification method according to claim 1, characterized in that, S8 specifically involves calculating the probability that the target is a false target: Error = a × B fp +b×L fp +c×P fp ; When Error > δ, the confidence level of the target being a false target is high; otherwise, it is low.

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