Method for testing anti-jamming performance of pulse laser radar

Abstract

The present application relates to the technical field of laser radar performance test, especially to a kind of pulsed laser radar anti-interference performance test method.The method comprises: placing the radar to be tested and the interference source closely and side by side along the horizontal direction, and placing the photoelectric detector along the vertical direction;opening the radar to be tested and the interference source preheating, observing the pulse form and pulse period of the radar to be tested using the photoelectric detector;adjusting the pulse form, pulse period and trigger delay of the interference source, so that it is consistent with the pulse form and pulse period of the radar to be tested, and the pulse time is synchronized;placing a reflecting plate in front of the radar to be tested, so that the normal line of the reflecting plate is parallel to the optical axis of the radar to be tested;adjusting the exit direction of the interference source;turning off or on the interference source, and collecting the test results of the radar to be tested when there is no or there is interference at the center of the field of view of the radar to be tested;judging the anti-interference performance of the radar to be tested according to the test results.The advantage is that the temporal and spatial synchronization of the interference source and the radar to be tested is realized.

Description

Technical Field

[0001] This invention relates to the field of lidar performance testing technology, and in particular to a method for testing the anti-interference performance of pulse lidar. Background Technology

[0002] LiDAR technology is a novel product that combines laser technology with traditional radar technology, offering unique advantages. Leveraging the advantages of lasers—small emission angle, concentrated energy, and high coherence—LiDAR technology can achieve special advantages that traditional radar technology lacks. Due to its superior performance, LiDAR has attracted attention in many fields. Besides autonomous driving applications, it is also needed in areas such as facial recognition, smart cities, robotics, and drones. However, with the increasing application of LiDAR, potential mutual interference is inevitable, making anti-interference performance one of the important indicators for LiDAR. Especially in the field of autonomous driving, the ability to resist interference directly affects the safety performance of the radar system; therefore, exploring the anti-interference capabilities of LiDAR is crucial.

[0003] In current anti-jamming tests, the radar under test is often placed in environments susceptible to direct or indirect interference. For example, in 2020, A. Carballo et al. from Nagoya University in Japan placed multiple lidars side-by-side and tested the interference between them by having multiple radars operate simultaneously. GB Popko et al. from West Point University in the United States placed the jamming radar and the radar under test in the same direction and simulated direct and indirect interference by having the jamming radar scan at different angles. However, in these testing methods, the jamming source and the lidar are not synchronized in the time domain and field of view (when the jamming source emits the jamming signal, the radar under test may not be in a detection state; when the jamming source emits the jamming signal from the right, the radar under test is receiving the signal from the left. In these cases, the radar under test cannot receive the jamming signal, and the test results are meaningless). Field-of-view synchronization means that the light emitted by the jamming source must be received by the receiver of the radar under test; time domain synchronization means that when the jamming source emits the jamming signal, the receiver of the radar under test is in a detection state. In current anti-interference testing methods, the interference source and the lidar are usually simply placed facing each other or in the same direction to simulate direct or indirect interference. The lack of synchronization between the time domain and the field of view means that the impact on the lidar is uncertain and random, and the test results lack persuasiveness.

[0004] Therefore, in order to meet the requirements of anti-interference testing for lidar, it is urgent to propose a time-domain and spatially synchronized testing method for anti-interference testing of pulse lidar. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for testing the anti-interference performance of pulsed lidar.

[0006] The purpose of this invention is to provide a method for testing the anti-interference performance of pulsed lidar, which specifically includes the following steps: S1. Place the radar under test and the interference source closely side by side in the horizontal direction, and place the photodetector in the vertical direction; turn on the radar under test and the interference source to preheat, and use the photodetector to observe the pulse pattern and pulse period of the radar under test. S2. Adjust the pulse form, pulse period and trigger delay of the interference source according to the radar under test, so that the pulse form and pulse period of the interference source are consistent with those of the radar under test and the pulse time is synchronized. S3. Place a reflector 8-12m in front of the radar under test, adjust the angle of the reflector so that the normal of the reflector is parallel to the optical axis of the radar under test, and set the center P of the reflector... test With respect to the field center V of the radar under test test Coincidentally; adjust the emission direction of the interference source so that the center P of the reflector plate coincides. test Located at the center of the light spot of the interference source; S4. Turn off the interference source, and at the center V of the field of view of the radar under test. test b frames of data are collected at the location to obtain b test results of the radar under test when there is no interference source, denoted as a0(k), k=1,2,3,...,b-1,b; S5. Turn on the interference source and adjust the trigger delay of the interference source relative to the radar under test; collect c sets of data under different trigger delays, with b frames of data collected in each set, to obtain c×b test results of the radar under test when interference exists, denoted as a. u (k), where u is the uth group of data and k is the test value of the kth frame in the uth group; S6. Determine the anti-interference performance of the radar under test based on the test results.

[0007] Preferably, step S6 includes the following sub-steps: S601. When u=1, the interference source has no interference effect on the radar under test, then x u,k =a u (k)-a0(k) is white noise; S602. Calculate the Ljung-Box statistic Q. u (m), as shown in the following formula: ; In the formula: T is the sample size, i.e., T=b; m is the lag rank or degrees of freedom; The autocorrelation coefficient of order n is expressed as: ; get in Let it be a chi-square random variable; S603, if p u A value greater than 0.05 indicates that the interference source has no effect on the radar under test under this trigger delay. S604. Take u=2, u=3, ..., u=c-1, u=c respectively, and calculate the trigger delay p for all u values. u Value, if all p u If all values ​​are greater than 0.05, the radar under test is determined to have anti-interference capability.

[0008] Preferably, b > 30 in steps S4 and S5, that is, more than 30 frames of data are collected.

[0009] Preferably, in step S5, the trigger delay is taken as 0~95% of the pulse period, in increments of 5%, and c=20.

[0010] Preferably, the interference source is a pulsed laser or a radar identical to the radar under test.

[0011] Preferably, the interference source is a pulsed laser, comprising multiple independently driven pulsed semiconductor lasers, which are combined and collimated to generate an interfering pulsed laser train; the size of the light spot formed by the collimated interference source on the reflector is larger than [a certain value] in both the horizontal and vertical directions. , where d is the distance from the interference source to the reflector, FoV is the field of view angle in the horizontal or vertical direction, and N is the number of pixels in the horizontal or vertical direction.

[0012] Preferably, a reflector is placed 10m in front of the radar under test.

[0013] Preferably, the distance between the radar under test and the interference source does not exceed 5cm.

[0014] Preferably, the preheating time for the radar under test and the interference source is 18-25 minutes.

[0015] Preferably, the preheating time for the radar under test and the interference source is 20 minutes.

[0016] Compared with the prior art, the present invention can achieve the following beneficial effects: The test method of this invention achieves spatiotemporal synchronization between the interference source and the radar under test, solving the problem of lack of reliability in current test methods, and providing a reliable, quantitative, and feasible test scheme for anti-interference testing of pulse lidar. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the pulse pattern and pulse period of a radar under test observed by a photoelectric detector according to an embodiment of the present invention.

[0018] Figure 2This is a schematic diagram illustrating the working principle of a pulsed laser according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the pulse waveforms before and after the trigger delay synchronization between the radar under test and the interference source according to an embodiment of the present invention; (A) not synchronized; (B) synchronized.

[0020] Figure 4 This is a top view schematic diagram of the placement position of the radar under test and the reflector according to an embodiment of the present invention.

[0021] Figure 5 This is a top view schematic diagram of the placement positions of the radar under test, the jamming radar, and the reflector according to an embodiment of the present invention.

[0022] Figure label: 1. Radar under test; 2. Interference source; 3. Collimator; 4. Photodetector; 5. Reflector. Detailed Implementation

[0023] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0025] This invention provides a method for testing the anti-interference performance of pulsed lidar, specifically including the following steps: S1. Place the radar under test and the interference source closely side by side in the horizontal direction, and place the photodetector in the vertical direction; turn on the radar under test and the interference source to preheat, and use the photodetector to observe the pulse pattern and pulse period of the radar under test. S2. Adjust the pulse form, pulse period and trigger delay of the interference source according to the radar under test, so that the pulse form and pulse period of the interference source are consistent with those of the radar under test and the pulse time is synchronized. S3. Place a reflector 8-12m in front of the radar under test, adjust the angle of the reflector so that the normal of the reflector is parallel to the optical axis of the radar under test, and set the center P of the reflector... test With respect to the field center V of the radar under test test Overlap; the direction of the interference source is adjusted so that the center P of the reflector plate coincides. test Located at the center of the light spot of the interference source; S4. Turn off the interference source, and at the center V of the field of view of the radar under test. test b frames of data are collected at the location to obtain b test results of the radar under test when there is no interference source, denoted as a0(k), k=1, 2, 3, ..., 49, 50; S5. Turn on the interference source and adjust the trigger delay of the interference source relative to the radar under test; collect c sets of data under different trigger delays, collecting b frames of data each time, to obtain c×b test results of the radar under test with interference present, denoted as a. u (k), where u is the uth group of data and k is the test value of the kth frame in the uth group; S6. Determine the anti-interference performance of the radar under test based on the test results; including the following sub-steps: S601. When u=1, the interference source has no interference effect on the radar under test, then x u,k =a u (k)-a0(k) is white noise; S602. Calculate the Ljung-Box statistic Q. u (m), as shown in the following formula: ; In the formula: T is the sample size, i.e., T=b; m is the lag rank or degrees of freedom; The autocorrelation coefficient of order n is expressed as: ; get in Let it be a chi-square random variable; S603, if p u A value greater than 0.05 indicates that the interference source has no effect on the radar under test under this trigger delay. S604, Calculate p for all trigger delays. u Value, if all p u If all values ​​are greater than 0.05, the radar under test is determined to have anti-interference capability.

[0026] In a specific embodiment, b=50 in steps S4 and S5, that is, 50 frames of data are collected; in step S5, the trigger delay is taken as 0~95% of the pulse period, with a step of 5%, and c=20.

[0027] In a specific embodiment, the interference source is a pulsed laser, comprising multiple independently driven pulsed semiconductor lasers, which, after beam combining and collimation, generate an interfering pulsed laser train; the size of the light spot formed by the collimated interference source on the reflector is larger than [a certain value] in both the horizontal and vertical directions. , where d is the distance from the interference source to the reflector, FoV is the field of view angle in the horizontal or vertical direction, and N is the number of pixels in the horizontal or vertical direction.

[0028] In a specific embodiment, the trigger delay of the interference source can also be generated by a multi-channel signal generator.

[0029] In a specific embodiment, a reflector is placed 10m in front of the radar under test.

[0030] In a specific embodiment, the distance between the radar under test and the interference source does not exceed 5cm.

[0031] In a specific embodiment, the preheating time for the radar under test and the interference source is 20 minutes.

[0032] Example 1 The test method for the anti-interference performance of pulsed lidar includes the following steps: S1, such as Figure 1 As shown, the radar under test 1 and the interference source 2 are placed closely side by side in the horizontal direction (the distance between them is about 3~5cm). The photodetector 4 is placed in the vertical direction. The distance between the radar under test 1 and the photodetector 4 is much greater than the distance between the radar under test 1 and the interference source 2. Turn on the radar under test 1 and the interference source 2 to preheat for 20 minutes. Use the photodetector 4 to observe the pulse pattern and pulse period of the radar under test 1.

[0033] S2. Adjust the pulse pattern, pulse period, and trigger delay of the interference source 2 according to the radar under test 1, so that the pulse pattern and pulse period of the interference source 2 are consistent with those of the radar under test 1, and the pulse time is synchronized (the pulse waveforms before and after synchronization are as follows). Figure 3 ); See Figure 2 Interference source 2 is a pulsed laser, comprising multiple independently driven pulsed semiconductor lasers. After beam combining and collimation, it generates an interfering pulsed laser train (the dashed lines in the figure represent the four sets of trigger signals corresponding to each independently driven pulsed semiconductor laser, and the output arrows represent beam combining and collimation). The size of the light spot formed by the collimated interference source on the reflector is larger than [a certain value] in both the horizontal and vertical directions. , where d is the distance from the interference source to the reflector, FoV is the field of view angle in the horizontal or vertical direction, and N is the number of pixels in the horizontal or vertical direction.

[0034] S3, such as Figure 4 At the position shown, a reflector 5 is placed 10m in front of the radar under test. The angle of the reflector 5 is adjusted so that the normal of the reflector 5 is parallel to the optical axis of the radar under test 1, and the center P of the reflector 5 is set... test With the center of the field of view V of the radar under test 1 test Coincident; adjust the emission direction of interference source 2 so that the center P of reflector 5 coincides. test The center of the light spot is located at the interference source 2.

[0035] S4. Turn off interference source 2, and position V at the center of the field of view of the radar under test 1. test 50 frames of data were collected to obtain 50 test results of the radar under test without the interference source, denoted as a0(k), k=1, 2, 3, ..., 49, 50.

[0036] S5. Turn on the interference source and adjust the trigger delay of the interference source relative to the radar under test. The trigger delay is set to 0-95% of the pulse period, in 5% increments. Collect 20 sets of data under different trigger delays (50 frames at 0% delay, 50 frames at 5% delay, 50 frames at 10% delay, and so on). Collect 50 frames of data each time to obtain 1000 test results of the radar under test with interference present, denoted as a. u (k), where u is the data of the uth group and k is the test value of the kth frame in the uth group.

[0037] S6. Determine the anti-interference performance of the radar under test based on the test results; including the following sub-steps: S601. When u=1, the interference source has no interference effect on the radar under test, then x u,k =a u (k)-a0(k) is white noise; S602. Calculate the Ljung-Box statistic Q. u (m), as shown in the following formula: ; In the formula: T is the sample size, which is 50 frames of data collected in this embodiment, i.e., T=50; m is the lag rank or degrees of freedom, which is usually 1. The autocorrelation coefficient of order n is expressed as: ; get in Let it be a chi-square random variable; S603, if p u A value greater than 0.05 indicates that the interference source has no effect on the radar under test under this trigger delay. S604. Taking u=2, u=3, ..., u=19, u=20 respectively, calculate the trigger delay p for all u values. u Value, if all p u If all values ​​are greater than 0.05, the radar under test is determined to have anti-interference capability.

[0038] Example 2 See Figure 5In the test method for anti-interference performance of pulse lidar, the interference source can also be a radar of the same type as the radar under test (as an interfering radar, i.e., the interference source). This method measures the anti-interference performance between two radars, which is beneficial for providing an anti-interference performance test method when multiple radars are operating.

[0039] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0040] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for testing the anti-interference performance of pulsed lidar, characterized in that, Specifically, the steps include the following: S1. Place the radar under test and the interference source closely side by side in the horizontal direction, and place the photodetector in the vertical direction; turn on the radar under test and the interference source to preheat, and use the photodetector to observe the pulse pattern and pulse period of the radar under test. S2. Adjust the pulse form, pulse period, and trigger delay of the interference source according to the radar under test, so that the pulse form and pulse period of the interference source are consistent with those of the radar under test, and the pulse time is synchronized. S3. Place a reflector 8-12m in front of the radar under test, adjust the angle of the reflector so that the normal of the reflector is parallel to the optical axis of the radar under test, and set the center P of the reflector... test With respect to the field center V of the radar under test test Coincidentally; adjust the emission direction of the interference source so that the center P of the reflector plate coincides. test Located at the center of the light spot of the interference source; S4. Turn off the interference source, and at the center V of the field of view of the radar under test. test b frames of data are collected at the location to obtain b test results of the radar under test when there is no interference source, denoted as a0(k), k=1,2,3,...,b-1,b; S5. Turn on the interference source and adjust the trigger delay of the interference source relative to the radar under test; collect c sets of data under different trigger delays, with b frames of data collected in each set, to obtain c×b test results of the radar under test with interference present, denoted as a. u (k), where u is the uth group of data and k is the test value of the kth frame in the uth group; S6. Determine the anti-interference performance of the radar under test based on the test results; including the following sub-steps: S601. When u=1, the interference source has no interference effect on the radar under test, then x u,k =a u (k)-a0(k) is white noise; S602. Calculate the Ljung-Box statistic Q. u (m), as shown in the following formula: ； In the formula: T is the sample size, i.e., T=b; m is the lag rank or degrees of freedom; The autocorrelation coefficient of order n is expressed as: ； get in Let it be a chi-square random variable; S603, if p u A value greater than 0.05 indicates that the interference source has no effect on the radar under test under this trigger delay. S604. Take u=2, u=3, ..., u=c-1, u=c respectively, and calculate the trigger delay p for all u values. u Value, if all p u If all values ​​are greater than 0.05, the radar under test is determined to have anti-interference capability.

2. The method for testing the anti-interference performance of pulsed lidar according to claim 1, characterized in that: In steps S4 and S5, b > 30, meaning more than 30 frames of data are collected.

3. The method for testing the anti-interference performance of pulsed lidar according to claim 2, characterized in that: In step S5, the trigger delay is set to 0-95% of the pulse period, with a step size of 5%, and c=20.

4. The method for testing the anti-interference performance of pulsed lidar according to any one of claims 1-3, characterized in that: The interference source is a pulsed laser or a radar identical to the radar under test.

5. The method for testing the anti-interference performance of pulsed lidar according to claim 4, characterized in that: The interference source is a pulsed laser, comprising multiple independently driven pulsed semiconductor lasers, which, after beam combining and collimation, generate an interfering pulsed laser train; the size of the light spot formed by the collimated interference source on the reflector is larger than [a certain value] in both the horizontal and vertical directions. , where d is the distance from the interference source to the reflector, FoV is the field of view angle in the horizontal or vertical direction, and N is the number of pixels in the horizontal or vertical direction.

6. The method for testing the anti-interference performance of pulsed lidar according to claim 5, characterized in that: A reflector is placed 10m in front of the radar under test.

7. The method for testing the anti-interference performance of pulsed lidar according to claim 6, characterized in that: The distance between the radar under test and the interference source does not exceed 5cm.

8. The method for testing the anti-interference performance of pulsed lidar according to claim 7, characterized in that: The preheating time for the radar under test and the interference source is 18-25 minutes.

9. The method for testing the anti-interference performance of pulsed lidar according to claim 8, characterized in that: The preheating time for the radar under test and the interference source is 20 minutes.

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