Method and device for testing performance parameters of laser radar echo signal simulator

Abstract

The invention discloses a laser radar echo signal simulator performance parameter testing method and device, and belongs to the field of photoelectric information. The system comprises a simulation distance related parameter measuring device, a working wavelength measuring device, a view field and distortion measuring device, an output power related parameter measuring device, a scanning speed and frame frequency and waveform similarity measuring device, an angular resolution measuring device and a simulator position adjusting device. The view field and distortion testing device is composed of a camera, an adjusting frame and a hemispherical guide rail. The scanning speed and frame frequency measuring device is composed of a focusing lens, two photoelectric detectors and an oscilloscope. The output power related parameter measuring device is composed of a focusing lens and a power meter. The working wavelength measuring device is composed of a focusing lens, an optical attenuator and a wavemeter. The placing position of the simulator on the platform is preset in advance through the simulator position adjusting device, and the simulator is sent to a specified testing position by driving the adjusting frame and the simulator to slide on the guide rail.

Description

Technical Field

[0001] The invention belongs to the field of optoelectronic information and relates to a performance parameter testing device of a laser radar echo signal simulator. Background Art

[0002] LiDAR is a radar system that uses laser beams to detect target characteristics such as position and velocity. LiDAR signals can be divided into a transmission signal emitted by the laser and an echo signal received by the receiver. The transmission signal is an inherent signal that does not contain any target information. The echo signal is a modulated signal generated when the LiDAR transmission signal contacts the target and is affected by and stores various target information (such as distance and angular position). By analyzing and processing the echo signal, various target information such as distance, rate of change of distance (radial velocity), and azimuth altitude can be extracted.

[0003] A LiDAR echo signal simulator can provide a controllable optical echo signal for the LiDAR system under test under laboratory conditions. Currently, LiDARs can be broadly divided into two categories: array LiDARs and scanning LiDARs. Consequently, the corresponding simulators are also categorized as array LiDAR echo signal simulators and scanning LiDAR echo signal simulators. Different array LiDAR echo signal simulators operate on different principles, including electronic time-delay technology and optical true time-delay technology. Currently, the most common method is to use multiple lasers in a two-dimensional array to simulate a single full-field-of-view illumination. Scanning LiDAR echo signal simulators also operate on different principles, including mechanical rotation scanning, galvanometer rotation scanning, and optical phased array directional emission technology.

[0004] There's currently no clear, systematic method for evaluating the performance of lidar echo signal simulators. The performance of a lidar echo signal simulator directly affects the characteristics of the simulated echo signal. Therefore, building a test system for the relevant parameters of lidar echo signal simulators is crucial. Summary of the Invention

[0005] The purpose of the present invention is to provide a performance parameter testing method and testing device for a lidar echo signal simulator, which can measure parameters such as operating wavelength, field of view, angular resolution, distortion, maximum output power, power control resolution, power control accuracy, power stability, simulated distance range, simulated distance accuracy, simulated distance resolution, simulated distance stability, scanning speed, frame rate, and waveform similarity.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention discloses a performance parameter testing method and testing device for a laser radar echo signal simulator, comprising a simulation distance-related parameter measurement device, an operating wavelength measurement device, a field of view and distortion measurement device, an output power-related parameter measurement device, a scanning speed, frame rate, and waveform similarity measurement device, an angular resolution measurement device, and a simulator position adjustment device.

[0008] The field of view and distortion test device consists of a camera, an adjustment frame, and a hemispherical guide rail. The hemispherical guide rail is composed of two arc guide rails with an angle of 180°. Guide rail 1 is placed horizontally and guide rail 2 is fixed vertically. The simulator is placed in front of the hemispherical guide rail. The light-emitting surface of the simulator is always parallel to the XY plane, and the exit pupil of the simulator is located at the center of the hemispherical guide rail. The camera is equipped with a lens with known distortion. The camera is mounted on guide rail 1 through adjustment frame 1, and the camera can be slid on guide rail 1 by moving adjustment frame 1 to achieve 180° field of view coverage of the simulator in the horizontal direction. Guide rail 1 is mounted on guide rail 2 through adjustment frame 2. By moving adjustment frame 2, guide rail 1 and the camera can be slid on guide rail 2 to achieve 180° field of view coverage of the simulator in the vertical direction.

[0009] The simulated distance-related parameter measurement device consists of an externally triggered light source, a collimating lens, two spectroscopes with known reflectivity and transmittance, two focusing lenses, two photodetectors, and a time interval meter. Based on the principle of laser pulse time-of-flight ranging, the simulated distance range of the lidar echo signal simulator depends on the delay range of the echo signal.

[0010] The scanning speed and frame rate measurement device consists of a focusing lens, two photodetectors, and an oscilloscope. A focusing lens is placed in front of the simulator, with its entrance pupil aligned with the simulator's exit pupil. Two photodetectors are placed at the focusing lens's image-side focal plane. Photodetector 3 and photodetector 4 are at equal distances from the simulator and connected to the two channel ports of the oscilloscope.

[0011] The output power-related parameter measurement device consists of a focusing lens and a power meter. A focusing lens is placed in front of the simulator, with its entrance pupil aligned with the simulator's exit pupil. The power meter probe's photosensitive surface is placed at the focusing lens's image-side focal plane, ensuring that the size of the photosensitive surface is equal to or larger than the spot size formed by the simulator's echo signal on the focusing lens's image-side focal plane. This ensures accurate measurement of the simulator's output power.

[0012] The working wavelength measurement device consists of a focusing lens, an optical attenuator, and a wavelength meter. A focusing lens is placed in front of the simulator so that the entrance pupil of the focusing lens coincides with the exit pupil of the simulator, and a wavelength meter is placed at the image-side focal plane of the focusing lens.

[0013] The simulator position adjustment device is composed of a motor driver, a motor and a multi-dimensional adjustment frame.

[0014] (1) Method for testing the field of view and distortion of the laser radar echo signal simulator:

[0015] Use a signal generator to trigger the simulator. Adjust the camera on Guide Rail 1 in the positive direction of the X-axis until the camera captures the right edge of the simulator's generated image. Note the camera's angle θ1 at this point. Adjust the camera on Guide Rail 1 in the negative direction of the X-axis until the camera captures the left edge of the simulator's generated image. Note the camera's angle θ2 at this point. The simulator's horizontal field of view is the difference between θ2 and θ1. Adjust Adjustment Frame 2 so that Guide Rail 1 moves the camera along Guide Rail 2 in the positive direction of the Y-axis until the camera captures the top edge of the simulator's generated image. Note the camera's angle θ3 at this point. Move Guide Rail 1 and the camera on Guide Rail 2 in the negative direction of the Y-axis until the camera captures the bottom edge of the simulator's generated image. Note the camera's angle θ4 at this point. The simulator's vertical field of view is the difference between θ4 and θ3.

[0016] To measure distortion, a signal generator is used to trigger the simulator, causing it to generate a point array target with marked point angles. A camera with a lens of known distortion is then used to capture images of the point array at various angles. Assuming that at a horizontal angle θ and a vertical angle σ, the horizontal distance error between the actual point coordinates in the captured image and the theoretical point coordinates is △X, and the vertical distance error is △Y. The superimposed horizontal distortion of the simulator and camera at this angle is:

[0017]

[0018] Xθ is the horizontal distance between the theoretical point and the optical center at the horizontal angle θ.

[0019] The superimposed vertical distortion of the simulator and the camera at this angle:

[0020]

[0021] Yσ is the vertical distance between the theoretical point and the optical center at the horizontal angle σ. The horizontal and vertical distortions of the simulator are calculated by subtracting the known distortion of the camera lens from DTH and DTV.

[0022] (2) Method for testing the angular resolution of the laser radar echo signal simulator:

[0023] Place a focusing lens in front of the simulator so that its entrance pupil coincides with the simulator's exit pupil. Place an image sensor at the image-side focal plane of the focusing lens. Use a signal generator to trigger the simulator. Use the simulator to generate a point target, with echo signals all pointing in the same direction. After passing through the focusing lens, the echo signal is focused on the image sensor to form a light spot. Set the simulator to increase its minimum operating angle, then capture a new light spot through the image sensor. Measure the distance H between the two light spots, determine the focal length f of the focusing lens, and calculate the angular resolution θa of the lidar echo signal simulator:

[0024]

[0025] (3) Methods for testing the simulated distance range, simulated distance accuracy, simulated distance resolution, and simulated distance stability of the lidar echo signal simulator:

[0026] Set the simulator's delay time to maximum, turn on the externally triggered optical signal source, and convert the triggering optical signal into collimated light through the collimating lens assembly before directing it toward beamsplitter 1. The collimated light enters beamsplitter 1 at an angle of 45°. The simulator is positioned in the direction of the reflected light. Part of the light passes through beamsplitter 1 and is collected by photodetector 1, while another part is reflected by beamsplitter 1 and directed toward the simulator's light inlet. The simulator and photodetector 1 are equidistant from beamsplitter 1. After the simulator generates an echo signal, it travels toward beamsplitter 1 at an angle of 45°. Part of the echo signal is reflected by beamsplitter 1 toward the optical signal source, while another part passes through beamsplitter 1 and strikes beamsplitter 2. Part of this echo signal is reflected by beamsplitter 2 and collected by photodetector 2. The distance between the optical signal source and beamsplitter 1 is equal to the distance from beamsplitter 1 to beamsplitter 2 plus the distance from beamsplitter 2 to photodetector 2. Photodetectors 1 and 2 are connected to channels A and B of the time interval measuring instrument, respectively. By measuring the time interval between light entering the simulator and the simulator outputting the echo signal (i.e., the time interval between photodetector 1 receiving the light signal and photodetector 2 receiving the light signal), the maximum delay time Tmax of the simulator is calculated. Set the simulator's delay time to the minimum and follow the same test steps to obtain the simulator's minimum delay time Tmin. The simulated distance range d1 to d2 of the lidar echo signal simulator is calculated using the TOF ranging formula:

[0027]

[0028]

[0029] Where d1 is the minimum simulated distance, d2 is the maximum simulated distance, and C is the speed of light.

[0030] Regarding the measurement simulation distance resolution, the simulation distance resolution of the lidar echo signal simulator depends on the delay resolution of the echo signal.

[0031] Turn on the externally triggered optical signal source. The triggering light signal is converted into collimated light through the collimating lens assembly and then directed toward beamsplitter 1. The collimated light enters beamsplitter 1 at an angle of 45°. The simulator is positioned in the direction of the reflected light. Part of the light passes through beamsplitter 1 and is collected by photodetector 1, while another part is reflected by beamsplitter 1 and directed toward the simulator's light inlet. The simulator and photodetector 1 are equidistant from beamsplitter 1. After the simulator generates an echo signal, it is directed toward beamsplitter 1 at an angle of 45°. Part of the echo signal is reflected by beamsplitter 1 toward the optical signal source, while another part passes through beamsplitter 1 and strikes beamsplitter 2. Part of the echo signal is reflected by beamsplitter 2 and collected by photodetector 2. The distance between the optical signal source and beamsplitter 1 is equal to the distance from beamsplitter 1 to beamsplitter 2 plus the distance from beamsplitter 2 to photodetector 2. Photodetectors 1 and 2 are connected to channels A and B of the time interval measuring instrument, respectively. The simulator's delay time, △T1, is calculated by measuring the time interval between light entering the simulator and the simulator outputting the echo signal (i.e., the time interval between photodetector 1 receiving the light signal and photodetector 2 receiving the light signal). The simulator's delay time is set to increase by a minimum time adjustment, and the same test steps are followed to obtain the delay time, △T2. The delay resolution, △Tr, of the echo signal is:

[0032] ΔT r =ΔT2-ΔT1

[0033] The simulated distance resolution of the lidar echo signal simulator is calculated using the TOF ranging formula:

[0034]

[0035] Regarding the measurement simulation distance accuracy, the simulation distance accuracy of the lidar echo signal simulator depends on the delay accuracy of the echo signal.

[0036] Set the simulator's delay time to minimum, turn on the externally triggered optical signal source, and convert the triggering optical signal into collimated light through the collimating lens assembly before directing it toward beamsplitter 1. The collimated light enters beamsplitter 1 at an angle of 45°. The simulator is positioned in the direction of the reflected light. Part of the light passes through beamsplitter 1 and is collected by photodetector 1, while another part is reflected by beamsplitter 1 and directed toward the simulator's light inlet. The simulator and photodetector 1 are equidistant from beamsplitter 1. After the simulator generates an echo signal, it travels toward beamsplitter 1 at an angle of 45°. Part of the echo signal is reflected by beamsplitter 1 toward the optical signal source, while another part passes through beamsplitter 1 and strikes beamsplitter 2. Part of this echo signal is reflected by beamsplitter 2 and detected by photodetector 2. The distance between the optical signal source and beamsplitter 1 is equal to the distance from beamsplitter 1 to beamsplitter 2 plus the distance from beamsplitter 2 to photodetector 2. Photodetectors 1 and 2 are connected to channel ports A and B of the time interval measuring instrument, respectively. The time interval between when photodetector 1 receives the light signal and when photodetector 2 receives the light signal is measured. The minimum delay time △Tmin' of the simulator is calculated. The simulator's delay time is set from the minimum value, and the minimum time adjustment amount is increased each time. The same steps are then followed to test and obtain the delay time △T2'. The above steps are repeated until the simulator's delay time is set to the maximum value. The delay time △Tmax' is collected. The collected delay times △Tmin', △T2', △T3', ..., △Tmax' are compared with the theoretical delay times △TImin', △TI2', △TI3', ..., △TImax' of the simulator, which are gradually increased according to the minimum time adjustment amount. The maximum difference between the actual value and the theoretical value is:

[0037] Δ max =max(|ΔT n '-ΔT In |)

[0038] Where n = min, 2, 3, ..., max.

[0039] The simulation distance accuracy da of the simulator under test is calculated according to the following formula:

[0040]

[0041] Regarding the measurement simulation distance stability, the simulation distance stability of the lidar echo signal simulator depends on the delay stability of the echo signal.

[0042] Set the simulator's delay time to a certain value, turn on the externally triggered optical signal source, and convert the triggering optical signal into collimated light through a collimating lens assembly, which is then directed toward beamsplitter 1. The collimated light enters beamsplitter 1 at an angle of 45°. The simulator is positioned in the direction of the reflected light. Part of the light passes through beamsplitter 1 and is collected by photodetector 1, while another part is reflected by beamsplitter 1 and is directed toward the simulator's light inlet. The simulator and photodetector 1 are equidistant from beamsplitter 1. After the simulator generates an echo signal, it is directed toward beamsplitter 1 at an angle of 45°. Part of the echo signal is reflected by beamsplitter 1 and reaches the optical signal source, while another part passes through beamsplitter 1 and reaches beamsplitter 2. Part of this echo signal is reflected by beamsplitter 2 and is collected by photodetector 2. The distance between the optical signal source and beamsplitter 1 is equal to the distance from beamsplitter 1 to beamsplitter 2 plus the distance from beamsplitter 2 to photodetector 2. Photodetectors 1 and B are connected to channel ports A and B of the time interval measuring instrument respectively. The time interval between the light entering the simulator and the simulator outputting the echo signal (i.e., the time interval between the light signal received by photodetector 1 and the light signal received by photodetector 2) is observed and timing is started. If the time interval can be maintained without significant changes for a long time, it indicates that the simulation distance stability of the simulator meets the test requirements.

[0043] (4) Methods for testing the scanning speed, frame rate, and waveform similarity of the laser radar echo signal simulator:

[0044] Use a signal generator to trigger the simulator and measure the time t it takes for the echo signal to scan through the two photodetectors. Given that the distance between photodetector 3 and photodetector 4 and the simulator in the z-axis direction is K and the distance between them in the x-axis direction is L / 2, calculate the simulator's scanning speed using the following formula:

[0045]

[0046] Regarding measuring the frame rate of the lidar echo signal simulator, use a signal generator to trigger the simulator to work, and observe on the oscilloscope how many times the photodetector receives a complete lidar echo signal simulator pulse signal within 1 second, which is the frame rate of the lidar echo signal simulator.

[0047] Regarding measuring the waveform similarity of the lidar echo signal simulator, a signal generator is used to trigger the simulator to work. By comparing the waveform data collected on the oscilloscope with the echo signal waveform received by the lidar in the actual scene, the echo signal waveform similarity of the lidar echo signal simulator is analyzed.

[0048] (5) Methods for testing the maximum output power, power control resolution, power control accuracy, and power stability of the lidar echo signal simulator:

[0049] Set the echo signal power output by the simulator to the maximum, trigger the simulator with a signal generator, and after the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value Wmax'. Given that the transmittance of the focusing lens is λ, the maximum output power Wmax of the simulator is:

[0050]

[0051] To measure the power control resolution, use a signal generator to trigger the simulator. After the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value W1. Increase the output power of the simulator by a minimum power adjustment amount. After the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value W2. The power control resolution Wr of the simulator is:

[0052]

[0053] Regarding measuring power control accuracy, first set the simulator's output power to the minimum value, trigger the simulator with a signal generator, wait for the power meter reading to stabilize, record the power meter readings multiple times and calculate the average value Wmin', increase the simulator's output power by a minimum power adjustment amount, wait for the power meter reading to stabilize, record the power meter readings multiple times and calculate the average value W2', repeat the above steps until the simulator's output power is set to the maximum value, and collect the output power Wmax'. Compare this set of collected output power data Wmin', W2', W3', ..., Wmax' with the simulator's theoretical output power WImin, WI2, WI3, ..., WImax, which is gradually increased from the minimum output power according to the minimum power adjustment amount. The maximum difference between the actual value and the theoretical value is:

[0054] Δ max =max(|W n '-W In |)

[0055] Where n = min, 2, 3, ..., max.

[0056] The power control accuracy Wa of the simulator under test is calculated according to the following formula:

[0057]

[0058] Regarding measuring power stability, use a signal generator to trigger the simulator, set the simulator output power to the maximum value, and start timing after the power meter reading stabilizes. If the output power reading does not change significantly for a long time, it indicates that the power stability of the simulator meets the test requirements.

[0059] (6) Method for testing the operating wavelength of the laser radar echo signal simulator:

[0060] Set the wavelength meter's working mode to pulse mode, set the simulator's output power to below the wavelength meter's maximum allowable power (an optical attenuator can be used if necessary), use a signal generator to trigger the simulator, and the wavelength meter collects the simulator's output signal to measure the lidar echo signal simulator's working wavelength.

[0061] (7) Function and working method of simulator position adjustment device:

[0062] Since this set of laser radar echo signal simulator performance parameter test device contains a large number of subsystems, in order to save time and manpower spent on moving the simulator when testing different parameters, this test system places the simulator on an adjustment frame that can move on a guide rail. In addition, since the working wavelength measurement device, field of view and distortion measurement device, output power related parameter measurement device, scanning speed and frame rate measurement device, and angular resolution measurement device all require that the simulator's exit pupil position coincide with the entrance pupil position of the focusing lens, it is necessary to first drive the motor to drive the adjustment frame and the simulator to slide on the guide rail, change the simulator's X-axis coordinate, and send the simulator to the designated test device. Then, use the motor drive to adjust the simulator's Y-axis and Z-axis coordinates through the adjustment frame so that the simulator's exit pupil position coincides with the entrance pupil position of the focusing lens of the test device, and then start the test.

[0063] Beneficial effects:

[0064] 1. There is currently no clear and systematic method for evaluating the performance of a laser radar echo signal simulator. The present invention discloses a method and device for testing the performance parameters of a laser radar echo signal simulator, comprising a simulated distance-related parameter measurement device, an operating wavelength measurement device, a field of view and distortion measurement device, an output power-related parameter measurement device, a scanning speed, frame rate and waveform similarity measurement device, an angular resolution measurement device, and a simulator position adjustment device. The simulator position adjustment device is used to preset the position of the simulator on the platform, so that after the simulator is placed and a certain parameter is measured, there is no need to adjust the position in the Y-axis and Z-axis directions. Instead, the motor needs to be driven to drive the platform and the simulator to slide on the guide rail, change the X-axis coordinate of the simulator, and send the simulator to the designated test position, thereby completing the testing of important parameters such as the operating wavelength, field of view, angular resolution, distortion, maximum output power, power control resolution, power control accuracy, power stability, simulated distance range, simulated distance accuracy, simulated distance resolution, simulated distance stability, scanning speed, frame rate, and waveform similarity of the laser radar echo signal simulator within a set of test systems.

[0065] 2. The present invention discloses a performance parameter testing method and testing device for a laser radar echo signal simulator. The field of view and distortion testing device is composed of a camera, an adjustment frame, and a hemispherical guide rail, wherein the hemispherical guide rail is composed of two circular arc guide rails with an angle of 180°. Guide rail 1 is placed horizontally and guide rail 2 is fixed vertically. The camera is installed on guide rail 1 through adjustment frame 1, and guide rail 1 is installed on guide rail 2 through adjustment frame 2. By moving adjustment frame 1, the camera can be slid on guide rail 1 to achieve 180° field of view coverage of the simulator in the horizontal direction. By moving adjustment frame 2, the guide rail 1 and the camera can be slid on guide rail 2 to achieve 180° field of view coverage of the simulator in the vertical direction.

[0066] 3. The performance parameter testing method and testing device of the laser radar echo signal simulator disclosed in the present invention realize the advance presetting of the placement position of the simulator on the platform through the simulator position adjustment device, so that after the simulator is placed and after the measurement of a certain parameter is completed, there is no need to adjust the position in the Y-axis and Z-axis directions. It is only necessary to drive the motor to drive the platform and the simulator to slide on the guide rail, change the X-axis coordinate of the simulator, and send the simulator to the specified test position. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 A schematic structural diagram of a performance parameter testing device for a laser radar echo signal simulator according to the present invention.

[0068] Figure 2 A schematic structural diagram of a field of view and distortion measurement device according to an embodiment of the present invention.

[0069] Figure 3 Schematic diagram of a measurement method for a field of view and distortion measurement device according to an embodiment of the present invention.

[0070] Figure 4 Schematic diagram of a measurement method of an angular resolution measurement device according to an embodiment of the present invention.

[0071] Figure 5 A schematic structural diagram of a device for measuring simulated distance-related parameters according to an embodiment of the present invention.

[0072] Figure 6 A schematic structural diagram of a device for measuring scanning speed, frame rate, and waveform similarity according to an embodiment of the present invention. DETAILED DESCRIPTION

[0073] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0074] The main indicators of the laser radar echo signal simulator performance parameter test device:

[0075] ①Working wavelength measurement range 200~2500nm:

[0076] Since the operating wavelengths of most lidars currently on the market are mainly distributed between 200 and 2300nm (for example, the typical wavelengths of vehicle-borne lidar are 905nm and 1550nm, the typical wavelengths of satellite-borne lidar are 532nm and 1064nm, the typical wavelengths of underwater lidar are 450-550nm, the typical wavelength of meteorological lidar is 355nm, and the typical wavelength of military lidar is 1500-2000nm), the corresponding operating wavelengths of lidar echo signal simulators are also mainly distributed between 200 and 2300nm. Therefore, the simulator performance parameter test device is designed to have an operating wavelength measurement range of 200-2500nm, which can basically meet the test requirements for different types of lidar echo signal simulators.

[0077] ② Field of view measurement range 180°×180°:

[0078] Currently, the typical horizontal field of view of mainstream solid-state lidar echo signal simulators is 60-120°, and the vertical field of view is 10-30°. The typical horizontal field of view of hybrid solid-state lidar echo signal simulators is 120-180°, and the vertical field of view is 25-40°. Therefore, designing the field of view measurement range of the simulator performance parameter test device to 180° horizontal field of view and 180° vertical field of view can meet the parameter testing requirements of most lidar echo signal simulators.

[0079] ③The camera’s resolution is greater than 12MP:

[0080] Ensure that the horizontal and vertical distortion of images with a distortion greater than 0.5% can be measured from the images captured by the camera;

[0081] ④ The focal length of the focusing lens 6 is ≥ 0.1m, and the interval between pixels on the image sensor is less than 0.2μm (to ensure that the simulator performance parameter test device can achieve the test capability of angular resolution ≤ 0.03°):

[0082] In general, the angular resolution range of the laser radar echo signal simulator can refer to the parameters of the actual laser radar. The angular resolution of the laser radar is generally 0.1° to 1°, and the simulator can even set the angular resolution to 0.05° in the case of high-precision simulation. In order to meet the test requirements for the simulator's angular resolution, the angular resolution index of the simulator performance parameter test device is designed to be less than or equal to 0.03°;

[0083] ⑤Output power measurement range 1μW~10W:

[0084] The power of the currently collected laser radar echo signal is generally between 0.1mW and 5W, so the power range of the laser radar echo signal simulator output signal is also roughly around 0.1mW to 7W. Therefore, the average power measurement range of the simulator performance parameter test device is designed to be 1μW to 10W;

[0085] ⑥Power resolution ≤ 20μW:

[0086] The power resolution of the laser radar echo signal simulator is generally greater than 50μW. The power resolution of the power meter simulator performance parameter test device is designed to be less than or equal to 20μW, which can basically meet the test requirements.

[0087] ⑦Power accuracy is within ±2μW:

[0088] Since the power accuracy of the lidar echo signal simulator is generally greater than ±10μW, the power accuracy of the simulator performance parameter test device is designed to be within ±2μW to meet the test requirements;

[0089] ⑧Delay time measurement range 1ps~1s:

[0090] The simulation distance range of the laser radar echo signal simulator depends on the delay time of the echo signal. Currently, the detection range of the laser radar does not exceed 1.5×108 meters, so the echo signal delay time of the laser radar echo signal simulator does not exceed 1s. The detection range is not less than 1.5×10-4 meters, so the echo signal delay time of the laser radar echo signal simulator does not exceed 1ps. The delay time measurement range of the simulator performance parameter test device is designed to be 1ps to 1s to meet the test requirements.

[0091] ⑨Delay time resolution ≤ 1ps:

[0092] The delay time resolution of the lidar echo signal simulator is generally greater than 10ps, and the power resolution of the power meter simulator performance parameter test device is designed to be less than or equal to 1ps, which can basically meet the test requirements;

[0093] ⑩Delay time measurement accuracy within ±0.2ps:

[0094] Since the delay time measurement accuracy of the lidar echo signal simulator is generally greater than ±2ps, the power accuracy of the simulator performance parameter test device is designed to be within ±0.2ps to meet the test requirements;

[0095] The response time of the photodetector is ≤ 1ns, the bandwidth is ≥ 1GHz, and the bandwidth of the oscilloscope is ≥ 1GHz:

[0096] Ensure that the photoelectric detector can collect the output signal of the high-speed scanning lidar echo signal simulator.

[0097] like Figure 1 As shown, the laser radar echo signal simulator performance parameter testing method and testing device disclosed in this embodiment are composed of seven devices: a simulation distance related parameter measurement device, an operating wavelength measurement device, a field of view and distortion measurement device, an output power related parameter measurement device, a scanning speed and frame rate and waveform similarity measurement device, an angular resolution measurement device, and a simulator position adjustment device.

[0098] The device for measuring simulated distance-related parameters includes an external trigger light source, a collimating lens, two beam splitters, two focusing lenses, two photodetectors, and a time interval meter. The external trigger light source replaces the laser radar (LiDAR) and triggers the laser radar echo signal simulator to generate an echo signal. The collimating lens collimates the light generated by the external trigger light source, allowing it to strike beam splitter 1 at an angle of incidence of 45°. Both beam splitter 1 and beam splitter 2 have a reflection-transmittance ratio of α:β (α and β are percentages, e.g., α = 50% and β = 50%). This means that for light incident on the surface of beam splitter 1 or 2 at a 45° angle, α of the light is reflected and β of the light is transmitted. Focusing lens 1 focuses the light transmitted from beam splitter 1 onto the photosensitive surface of photodetector 1. The distance between photodetector 1 and the lidar echo signal simulator and spectroscope 1 is 70 cm. Therefore, the time it takes for the light generated by the external trigger light signal source to reach the simulator after being reflected by spectroscope 1 is equal to the time it takes for the light generated by the external trigger light signal source to reach photodetector 1 after passing through spectroscope 1. Therefore, the function of photodetector 1 is to determine the time tin when the light enters the simulator. After receiving the trigger signal, the simulator generates an echo signal, which strikes spectroscope 1 at an incident angle of 45°. The α light is reflected to the collimating lens and enters the external trigger light signal source. The β light passes through spectroscope 1 and strikes spectroscope 2 at an incident angle of 45°. Spectroscope 2 reflects the α light to focusing lens 2, where it is collected by photodetector 2. The distance between photodetector 2 and spectroscope 2 is 70 cm, the distance between spectroscope 1 and spectroscope 2 is 30 cm, and the distance between the external trigger light source and spectroscope 1 is 100 cm. Therefore, the total distance the simulator-generated echo signal travels through spectroscope 1 and the collimating lens to the external trigger light source is 170 cm. The total distance the simulator-generated echo signal travels through spectroscope 1, spectroscope 2, and focusing lens 2 to photodetector 2 is also 170 cm. Therefore, the function of photodetector 2 is to determine the instant tout at which the echo signal enters the external trigger light source. The function of the time interval meter is to measure the time difference between the two photodetectors receiving the signal, thereby measuring the extended time of the simulator echo signal. This embodiment uses a high-precision time interval meter with a time resolution of 1 ps, which meets the requirements of the simulator performance parameter test device.

[0099] By calculating the time interval between the moment tin when the external trigger light enters the simulator and the moment tout when the echo signal enters the external trigger light signal source (i.e., the time interval △t between the moment tin when the photodetector 1 receives the light signal and the moment tout when the photodetector 2 receives the light signal), △t is the delay time of the simulator echo signal, and the simulation distance of the simulator is d:

[0100] Δt=t out -tin

[0101]

[0102] Where C is the speed of light.

[0103] In this embodiment, the simulator echo signal delay time is set to the maximum value. The time interval measuring instrument measures Δtmax = 1000004 ps, so the maximum delay time of the simulator echo signal is 1000004 ps. The maximum simulated distance of the simulator is calculated as:

[0104]

[0105] Therefore, the simulation distance range of the simulator is 0 to 150m.

[0106] The simulator echo signal delay time is set to 500ns, and the time interval measurement instrument measures △t500 = 500003ps. The simulator echo signal delay time is increased by a minimum time adjustment of 1ns, and the time interval measurement instrument is used again to measure △t501 = 501001ps. The delay resolution △tr of the simulator echo signal is:

[0107] Δt r =Δt 501 -Δt 500 =501001ps-500003ps=998ps

[0108] The simulated distance resolution dr of the lidar echo signal simulator can be calculated:

[0109]

[0110] The simulator echo signal delay time is set to 1ns, and the time interval measuring instrument measures △t1 = 1003ps. The difference △1 between the actual measured value and the theoretical set value is calculated as follows:

[0111] Δ1=Δt1-1=1003ps-1000ps=3ps

[0112] Then increase the simulator echo signal delay time to 2ns. The time interval meter measures △t2 = 1998ps, and calculates △2 = -2ps. Follow the same steps to obtain △3, △4, △5, △6, and so on, and continue until the simulator echo signal delay time is increased to the maximum value of 1000ns. The time interval meter measures △t1000 = 1000004ps, and calculates △1000 = 4ps. The maximum absolute value of the difference between the actual measured value and the theoretical set value is △max:

[0113] Δmax =max(|Δt n -n|)

[0114] Where n = 1, 2, 3, ..., 1000. In this example, Δmax = |Δ732-732| = 5 ps, so the simulated distance accuracy da of the laser radar echo signal simulator is:

[0115]

[0116] Set the simulator echo signal delay time to 1000ns and make the simulator work for a long time. Measure △t1000 every 30 minutes with a time interval meter until |△t1000-1000000ps| is greater than 5ps. Record the simulator continuous working time T. In this embodiment, T = 8 hours, so 8 hours is the simulator simulation distance stabilization time.

[0117] The operating wavelength measurement device includes a focusing lens 3, an optical attenuator, and a wavelength meter. The focusing lens 3 focuses the echo signal generated by the simulator onto the wavelength meter's light input port. The optical attenuator ensures that the simulator's output power is below the wavelength meter's maximum allowable power, protecting the wavelength meter from damage by high-power echo signals. The wavelength meter measures the wavelength of the simulator's echo signal.

[0118] In this embodiment, the simulator outputs a pulsed echo signal, so the wavelength meter is set to pulse mode. The simulator's output power is set below the wavelength meter's maximum allowable power (an optical attenuator can be used if necessary). The simulator is triggered by a signal generator, and the simulator's output signal passes through focusing lens 3 and enters the wavelength meter. The measured operating wavelength of the lidar echo signal simulator is 905 nm.

[0119] The field of view and distortion measurement device consists of a camera, an adjustment mount, and a hemispherical guide rail. The adjustment mount consists of two circular rails, each with an angle of 180° and a radius of 35 cm. Rail 1 is horizontal, while Rail 2 is fixed vertically. The camera is equipped with a lens with a known distortion of 2%. The camera has a field of view of 20° horizontally and 10° vertically, and a resolution of 4096 × 3000. The camera is used to capture images of the echo signals generated by the simulator. Adjustment mount 1 enables the camera to move horizontally on Guide Rail 1, while adjustment mount 2 enables the vertical movement of Guide Rail 1 and the camera on Guide Rail 2. The camera is mounted on Guide Rail 1 via adjustment mount 1 and can be slid along Guide Rail 1 by moving adjustment mount 1, achieving 180° horizontal coverage of the simulator's field of view. The guide rail 1 is mounted on the guide rail 2 through the adjustment frame 2. The guide rail 1 and the camera slide on the guide rail 2 by moving the adjustment frame 2, thereby achieving 180° field of view coverage of the simulator in the vertical direction.

[0120] Place the simulator in front of the hemispherical guide rail, with the simulator's light-emitting surface always parallel to the XY plane, and the simulator's exit pupil located at the center of the hemispherical guide rail. Use a signal generator to trigger the simulator, and adjust the camera to move in the positive direction of the X axis on Guide Rail 1 until the camera captures the right edge of the simulator's generated image. Note the camera's angle at this point, θ1 = +60°. Adjust the camera to move in the negative direction of the X axis on Guide Rail 1 until the camera captures the left edge of the simulator's generated image. Note the camera's angle at this point, θ2 = -60°. Therefore, the simulator's horizontal field of view (HFOV) is:

[0121] HFOV=θ1-θ2=120°

[0122] Adjustment frame 2 so that guide rail 1 and the camera move on guide rail 2 in the positive direction of the Y axis until the camera captures the top edge of the field of view of the simulator-generated image. Note the angle θ3 of the camera at this time = +30°. Move guide rail 1 and the camera on guide rail 2 in the negative direction of the Y axis until the camera captures the bottom edge of the field of view of the simulator-generated image. Note the angle θ4 of the camera at this time = -30°. Therefore, the vertical field of view VFOV of the simulator is:

[0123] VFOV=θ3-θ4=60°

[0124] The simulator generates a point array target with a marked point angle. A camera with a 2% lens distortion is used to capture a point array image at a horizontal angle of +20° and a vertical angle of +10°. The measured horizontal distance error between the actual point coordinates in the captured image and the theoretical point coordinates is +1.50mm, and the vertical distance error is +0.69mm. X+20 is the horizontal distance between the theoretical point and the optical center at a horizontal angle of +20°, and Y+10 is the vertical distance between the theoretical point and the optical center at a vertical angle of +10°. In this embodiment, X+20 = 60mm and Y+10 = 29mm. The superimposed horizontal distortion DTH1 of the simulator and camera at a horizontal angle of +20° and a vertical angle of +10° is:

[0125]

[0126] The superimposed vertical distortion DTV10 of the simulator and the camera at this angle is:

[0127]

[0128] So the simulator has horizontal distortion DTMH20 and vertical distortion DTMV10 at a horizontal angle of +20° and a vertical angle of +10°:

[0129] DT MH20 =2.50%-2%=0.50%

[0130] DT MV10 =2.38%-2%=0.38%

[0131] A camera is used to capture a point array image at a horizontal angle of +60° and a vertical angle of 5°. The horizontal distance error between the actual point coordinates in the captured image and the theoretical point coordinates is measured to be +17.70mm, and the vertical distance error is +0.33mm. X+60 is the horizontal distance between the theoretical point and the optical center at a horizontal angle of +60°, and Y5 is the vertical distance between the theoretical point and the optical center at a vertical angle of 5°. In this embodiment, X+60 = 285.5mm, and Y5 = 14.4mm. The superimposed horizontal distortion DTH120 of the simulator and camera at a horizontal angle of +60° and a vertical angle of 0° is:

[0132]

[0133] The superimposed vertical distortion DTV0 of the simulator and the camera at this angle is:

[0134]

[0135] So the simulator has horizontal distortion DTMH1 and vertical distortion DTMV10 at a horizontal angle of +60° and a vertical angle of +5°:

[0136] DT MH60=6.20%-2%=4.20%

[0137] DT MV5 =2.30%-2%=0.30%

[0138] The output power-related parameter measurement device includes a focusing lens 4 and a power meter. The focusing lens 4 focuses the simulator's echo signal onto the power meter's photosensitive surface. The power meter has a power measurement range of 1μW to 20W and a power resolution of 1μW. The photosensitive surface of the power meter is 100mm². The power meter measures the power of the simulator's echo signal.

[0139] Set the simulator's output echo signal power to maximum, trigger the simulator with a signal generator, and after the power meter reading stabilizes, record the power meter readings multiple times and calculate the average value, Wmax' = 294μW. Given that the focusing lens's transmittance λ = 70%, the simulator's maximum output power, Wmax, is:

[0140]

[0141] Set the simulator's output echo signal power to 200μW. After the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value W1 = 141μW. Increase the simulator's output power by a minimum power adjustment amount. After the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value W2 = 150μW. The simulator's power control resolution Wr is:

[0142]

[0143] Set the output power of the simulator to 0μW, record the reading on the power meter W1'=0μW, increase the output power of the simulator by a minimum power adjustment amount of 10μW, and after the power meter reading stabilizes, record the reading on the power meter multiple times and calculate the average value W2'=7μW. Repeat the above steps until the output power of the simulator is set to the maximum value of 420μW, record the reading on the power meter multiple times and calculate the average value W42'=294μW, and compare the collected output power data W1', W2', W3', ..., W42' with the theoretical output power WL1=0μW, WL2=7μW, WL3=14μW, ..., WL42=294W on the simulator, which is gradually increased from the minimum output power according to the minimum power adjustment amount. The maximum absolute value of the difference between the actual measured value and the theoretical set value is △Wmax:

[0144] ΔW max =max(|W n '-W Ln |)

[0145] Where n = 1, 2, 3, ..., 42.

[0146] In this embodiment, ΔWmax=|W25′-WL25|=2μW, and the power control accuracy Wa of the simulator under test is calculated as follows:

[0147]

[0148] Set the simulator output power to 420 μW and allow the simulator to operate for a long time. Measure W42' with a power meter every 30 minutes until |W42'-294 μW| is greater than 2 μW. Record the simulator's continuous operating time T. In this embodiment, T = 8 hours, so 8 hours is the simulator's output power stabilization time.

[0149] The scanning speed, frame rate, and waveform similarity measurement device consists of a focusing lens 5, photodetectors 3 and 4, and an oscilloscope. The focusing lens 5 focuses the echo signal generated by the simulator onto the photosensitive surface of the photodetectors. The two photodetectors have a response time of ≤1ns and a bandwidth of ≥1GHz. The photodetectors capture the waveform of the echo signal generated by the simulator. The oscilloscope stores the waveform of the echo signal captured by the photodetectors and records the time it takes for the echo signal to scan through the two photodetectors.

[0150] The simulator is triggered by a signal generator. The time ts = 50 ms taken for the echo signal to scan through photodetectors 3 and 4 is read on the oscilloscope. Given that the distance between photodetectors 3 and 4 and the simulator in the z-axis direction is K = 1 m, and the distance between the two photodetectors in the x-axis direction is L = 2 m, the simulator's scanning angular velocity ω is calculated using the following formula:

[0151]

[0152] It was observed on the oscilloscope that the photodetector collected five complete echo signal pulse trains within 1s, so the frame rate of the simulator was 5Hz.

[0153] By comparing the echo signal waveform collected on the oscilloscope with the echo signal waveform received by the lidar in the actual scene, the similarity of the simulator's echo signal waveform can be analyzed.

[0154] The angular resolution measurement device includes a focusing lens 6 and an image sensor. The focal length of focusing lens 6 is 0.1 m. It focuses the simulator's echo signal onto the image sensor. The pixel spacing on the image sensor is less than 0.2 μm. The image sensor measures the distance between the two light spots formed by the simulator's echo signal after it passes through focusing lens 6.

[0155] Use a signal generator to trigger the simulator. Use the simulator to generate a point target. The echo signals all point in the same direction. After passing through the focusing lens 6, the echo signals are focused on the image sensor to form a light spot. Set the simulator to increase a minimum working angle. Then, use the image sensor to collect a new light spot. Measure the distance between the two light spots. H = 170μm. Adding the known focal length of the focusing lens 6 f = 0.1m, calculate the angular resolution θa of the lidar echo signal simulator according to the following formula:

[0156]

[0157] The simulator position adjustment device consists of a motor driver and a motor. The motor driver drives the motor, which pushes the simulator along the guide rails to move it to the designated test position. The guide rails facilitate the simulator's ability to change measurement positions. The signal generator provides trigger signals to the simulator, generating echo signals when measuring parameters such as the simulator's operating wavelength, field of view, distortion, output power, scanning speed, frame rate, waveform similarity, and angular resolution.

[0158] The above specific description further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method and device for testing the performance parameters of a laser radar echo signal simulator, characterized by: It includes a simulation distance related parameter measurement device, an operating wavelength measurement device, a field of view and distortion measurement device, an output power related parameter measurement device, a scanning speed and frame rate and waveform similarity measurement device, an angular resolution measurement device, and a simulator position adjustment device; The field of view and distortion test device consists of a camera, an adjustment frame, and a hemispherical guide rail. The hemispherical guide rail is composed of two circular arc guide rails with an angle of 180°. The device for measuring analog distance-related parameters consists of an external trigger light signal source, a collimating lens, two spectroscopes with known reflectivity and transmittance, two focusing lenses, two photodetectors and a time interval measuring instrument. The scanning speed and frame rate measurement device consists of a focusing lens, two photodetectors and an oscilloscope; The output power related parameter measurement device consists of a focusing lens and a power meter; The working wavelength measurement device consists of a focusing lens, optical attenuator and wavelength meter; The simulator position adjustment device consists of a motor driver and a motor.

2. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 1, wherein: In the field of view and distortion test device, guide rail 1 is placed horizontally and guide rail 2 is fixed vertically; the simulator is placed in front of the hemispherical guide rail, with the simulator's light-emitting surface always parallel to the XY plane, and the simulator's exit pupil is located at the center of the hemispherical guide rail; the camera has a lens with known distortion, and the camera is mounted on guide rail 1 via adjustment bracket 1. The camera can slide on guide rail 1 by moving adjustment bracket 1 to achieve 180° horizontal field of view coverage of the simulator; guide rail 1 is mounted on guide rail 2 via adjustment bracket 2, and guide rail 1 and the camera can slide on guide rail 2 by moving adjustment bracket 2 to achieve 180° vertical field of view coverage of the simulator; In the scanning speed and frame rate measurement device, a focusing lens is placed in front of the simulator so that the entrance pupil of the focusing lens coincides with the exit pupil of the simulator. Two photodetectors are placed at the image-side focal plane of the focusing lens. Photodetector 3 and photodetector 4 are at the same distance from the simulator. The two photodetectors are connected to two channel ports of the oscilloscope respectively. In the output power related parameter measurement device, a focusing lens is placed in front of the simulator so that the entrance pupil position of the focusing lens coincides with the exit pupil position of the simulator. The photosensitive surface of the power meter probe is placed at the image side focal plane position of the focusing lens. The size of the photosensitive surface must be greater than or equal to the spot size formed by the simulator echo signal on the image side focal plane of the focusing lens to ensure that the output power of the simulator can be accurately measured. In the working wavelength measurement device, a focusing lens is placed in front of the simulator so that the entrance pupil position of the focusing lens coincides with the exit pupil position of the simulator, and a wavelength meter is placed at the image side focal plane position of the focusing lens.

3. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The method for testing the field of view and distortion of the lidar echo signal simulator is as follows: Use the signal generator to trigger the simulator to work, adjust the camera to move in the positive direction of the X axis on the guide rail 1 until the camera captures the right edge field of view of the image generated by the simulator, and note the angle θ1 of the camera's position at this time, adjust the camera to move in the negative direction of the X axis on the guide rail 1 until the camera captures the left edge field of view of the image generated by the simulator, and note the angle θ2 of the camera's position at this time. The horizontal field of view range of the simulator is the difference between the angles θ2 and θ1; adjust the adjustment frame 2 so that the guide rail 1 carries the camera to move in the positive direction of the Y axis on the guide rail 2 until the camera captures the top edge field of view of the image generated by the simulator, and note the angle θ3 of the camera's position at this time; move the guide rail 1 and the camera in the negative direction of the Y axis on the guide rail 2 until the camera captures the bottom edge field of view of the image generated by the simulator, and note the angle θ4 of the camera's position at this time. The vertical field of view range of the simulator is the difference between θ4 and θ3; To measure distortion, a signal generator is used to trigger the simulator, causing it to generate a point array target with a marked point angle. A camera with a lens of known distortion is used to capture point array images at various angles. When the horizontal angle θ and vertical angle σ are measured, the horizontal distance error between the actual point coordinates in the captured image and the theoretical point coordinates is △X, and the vertical distance error is △Y. The superimposed horizontal distortion of the simulator and camera at this angle is: Xθ is the horizontal distance between the theoretical point and the optical center at the horizontal angle θ; The superimposed vertical distortion of the simulator and the camera at this angle: Yσ is the vertical distance between the theoretical point and the optical center at the horizontal angle σ; the horizontal and vertical distortions of the simulator are calculated by subtracting the known distortion of the camera lens from DTH and DTV.

4. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The method for testing the angular resolution of the lidar echo signal simulator is: Place a focusing lens in front of the simulator so that the entrance pupil of the focusing lens coincides with the exit pupil of the simulator, and place an image sensor at the image-side focal plane of the focusing lens. Use a signal generator to trigger the simulator to work, and use the simulator to generate a point target. The echo signals all face the same direction. After passing through the focusing lens, the echo signal is focused on the image sensor to form a light spot. Set the simulator to increase a minimum working angle, and then collect a new light spot through the image sensor. Measure the distance H between the two light spots, and then determine the focal length f of the focusing lens to calculate the angular resolution θa of the lidar echo signal simulator:

5. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The method for testing the simulated distance range, simulated distance accuracy, simulated distance resolution, and simulated distance stability of the lidar echo signal simulator is as follows: Set the simulator's delay time to the maximum, turn on the externally triggered optical signal source, convert the trigger light signal into collimated light through the collimating lens group and then shoot it toward the spectroscope 1. The incident angle of the collimated light incident on the spectroscope 1 is 45°. The simulator is located in the direction of the reflected light. Part of the light passes through the spectroscope 1 and is collected by the photodetector 1, and the other part of the light is reflected by the spectroscope 1 to the light inlet of the simulator. The distance between the simulator and the photodetector 1 and the spectroscope 1 is equal. After the simulator generates an echo signal, the echo signal is shot toward the spectroscope 1 with an incident angle of 45°. A part of the The echo signal is reflected by spectroscope 1 to the optical signal source. Another portion of the echo signal passes through spectroscope 1 and strikes spectroscope 2, where part of the echo signal is reflected by spectroscope 2 and collected by photodetector 2. The distance between the optical signal source and spectroscope 1 is equal to the distance from spectroscope 1 to spectroscope 2 plus the distance from spectroscope 2 to photodetector 2. Photodetectors 1 and 2 are connected to channels A and B of the time interval measuring instrument, respectively. By measuring the time interval between light entering the simulator and the simulator outputting the echo signal, the maximum delay time Tmax of the simulator is calculated. Set the simulator's delay time to the minimum, and then follow the same steps to test the simulator to get the minimum delay time Tmin, and calculate the simulated distance range d1 to d2 of the lidar echo signal simulator using the TOF ranging formula: Where d1 is the minimum simulated distance, d2 is the maximum simulated distance, and C is the speed of light; Regarding the measurement simulation range resolution, the simulation range resolution of the lidar echo signal simulator depends on the delay resolution of the echo signal; Turn on the externally triggered optical signal source, convert the triggering optical signal into collimated light through the collimating lens group and then emit it to the spectroscope 1. The incident angle of the collimated light on the spectroscope 1 is 45°. The simulator is located in the direction of the reflected light. Part of the light passes through the spectroscope 1 and is collected by the photodetector 1, and the other part of the light is reflected by the spectroscope 1 to the light inlet of the simulator. The distance between the simulator and the photodetector 1 and the spectroscope 1 is equal; after the simulator generates an echo signal, the echo signal is emitted to the spectroscope 1 with an incident angle of 45°. Part of the echo signal is reflected by the spectroscope 1 to the optical signal source, and another part of the echo signal passes through the spectroscope 1 and is reflected to the light inlet of the simulator. The light is incident on spectroscope 2, where a portion of the echo signal is reflected by spectroscope 2 and collected by photodetector 2. The distance between the light source and spectroscope 1 is equal to the distance from spectroscope 1 to spectroscope 2 plus the distance from spectroscope 2 to photodetector 2. Photodetectors 1 and 2 are connected to channel ports A and B of the time interval measuring instrument, respectively. By measuring the time interval between the light entering the simulator and the simulator outputting the echo signal, the simulator's delay time △T1 is calculated. The simulator's delay time is set to increase by a minimum time adjustment amount, and the same test steps are followed to obtain the delay time △T2. The delay resolution △Tr of the echo signal is: ΔT r =ΔT2-ΔT1 The simulated distance resolution of the lidar echo signal simulator is calculated using the TOF ranging formula: Regarding the accuracy of the simulated distance measurement, the simulated distance accuracy of the lidar echo signal simulator depends on the delay accuracy of the echo signal; Set the simulator's delay time to the minimum, turn on the externally triggered optical signal source, convert the triggering optical signal into collimated light through the collimating lens group and then shoot it toward spectroscope 1. The incident angle of the collimated light on spectroscope 1 is 45°. The simulator is located in the direction of the reflected light. Part of the light passes through spectroscope 1 and is collected by photodetector 1, and the other part of the light is reflected by spectroscope 1 to the light inlet of the simulator. The distance between the simulator and photodetector 1 and spectroscope 1 is equal; after the simulator generates an echo signal, the echo signal is shot toward spectroscope 1 with an incident angle of 45°. Part of the echo signal is reflected by spectroscope 1 to the optical signal source, and part of the echo signal passes through spectroscope 1 and is irradiated to spectroscope 2. Part of the echo signal The split echo signal is reflected by spectroscope 2 and collected by photodetector 2. The distance between the optical signal source and spectroscope 1 is equal to the distance from spectroscope 1 to spectroscope 2 plus the distance from spectroscope 2 to photodetector 2. Photodetectors 1 and 2 are connected to channel ports A and B of the time interval measuring instrument, respectively. The time interval between the time when photodetector 1 receives the optical signal and the time when photodetector 2 receives the optical signal is measured, and the minimum delay time △Tmin' of the simulator is calculated. The delay time of the simulator is set from the minimum value, and the minimum time adjustment amount is increased each time. The delay time △T2' is then measured according to the same steps. The above steps are repeated until the simulator delay time is set to the maximum value, and the delay time △Tmax' is collected. The collected delay times △Tmin', △T2', △T3', ..., △Tmax' are compared with the theoretical delay times △TImin', △TI2', △TI3', ..., △TImax' of the simulator that are gradually increased according to the minimum time adjustment amount. The maximum difference between the actual value and the theoretical value is: D max =max(|ΔT n '-ΔT In |) Where n = min, 2, 3, ..., max; The simulation distance accuracy da of the simulator under test is calculated according to the following formula: Regarding the stability of the measured simulated distance, the simulated distance stability of the lidar echo signal simulator depends on the delay stability of the echo signal; Set the simulator's delay time to a certain value, turn on the externally triggered optical signal source, convert the trigger light signal into collimated light through the collimating lens group and then shoot it to a spectroscope 1. The incident angle of the collimated light on the spectroscope 1 is 45°. The simulator is located in the direction of the reflected light. Part of the light passes through the spectroscope 1 and is collected by the photodetector 1, and the other part of the light is reflected by the spectroscope 1 to the light inlet of the simulator. The distance between the simulator and the photodetector 1 and the spectroscope 1 is equal; after the simulator generates an echo signal, the echo signal is shot to the spectroscope 1 with an incident angle of 45°. A part of the echo signal is reflected by the spectroscope 1. The wave signal is reflected by spectroscope 1 to the optical signal source, and part of the echo signal passes through spectroscope 1 and illuminates spectroscope 2, of which part of the echo signal is reflected by spectroscope 2 and collected by photodetector 2; the distance between the optical signal source and spectroscope 1 is equal to the distance from spectroscope 1 to spectroscope 2 plus the distance from spectroscope 2 to photodetector 2; photodetectors 1 and B are respectively connected to channel ports A and B of the time interval measuring instrument. The time interval between the light entering the simulator and the simulator outputting the echo signal is observed and timing is started, which indicates that the simulator's simulated distance stability meets the test requirements.

6. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The method for testing the scanning speed, frame rate and waveform similarity of the lidar echo signal simulator is as follows: Use a signal generator to trigger the simulator and measure the time t it takes for the echo signal to scan through the two photodetectors. Given that the distance between photodetector 3 and photodetector 4 and the simulator in the z-axis direction is K and the distance between them in the x-axis direction is L / 2, calculate the simulator's scanning speed using the following formula: Regarding measuring the frame rate of the laser radar echo signal simulator, use a signal generator to trigger the simulator to work, and observe on the oscilloscope how many times the photodetector receives a complete laser radar echo signal simulator pulse signal within 1 second, which is the frame rate of the laser radar echo signal simulator; Regarding measuring the waveform similarity of the lidar echo signal simulator, a signal generator is used to trigger the simulator to work. By comparing the waveform data collected on the oscilloscope with the echo signal waveform received by the lidar in the actual scene, the echo signal waveform similarity of the lidar echo signal simulator is analyzed.

7. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The method for testing the maximum output power, power control resolution, power control accuracy, and power stability of the lidar echo signal simulator is as follows: Set the echo signal power output by the simulator to the maximum, trigger the simulator with a signal generator, and after the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value Wmax'. Given that the transmittance of the focusing lens is λ, the maximum output power Wmax of the simulator is: To measure the power control resolution, use a signal generator to trigger the simulator. After the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value W1. Increase the output power of the simulator by a minimum power adjustment amount. After the power meter reading stabilizes, record the readings on the power meter multiple times and calculate the average value W2. The power control resolution Wr of the simulator is: Regarding measuring power control accuracy, first set the simulator's output power to the minimum value, trigger the simulator with a signal generator, wait for the power meter reading to stabilize, record the power meter readings multiple times and calculate the average value Wmin', increase the simulator's output power by a minimum power adjustment amount, wait for the power meter reading to stabilize, record the power meter readings multiple times and calculate the average value W2', repeat the above steps until the simulator's output power is set to the maximum value, and collect the output power Wmax'. Compare this set of collected output power data Wmin', W2', W3', ..., Wmax' with the simulator's theoretical output power WImin, WI2, WI3, ..., WImax, which is gradually increased from the minimum output power according to the minimum power adjustment amount. The maximum difference between the actual value and the theoretical value is: Δ max =max(|W n '-IN In |) Where n = min, 2, 3, ..., max; The power control accuracy Wa of the simulator under test is calculated according to the following formula: Regarding measuring power stability, use a signal generator to trigger the simulator, set the simulator output power to the maximum value, and start timing after the power meter reading stabilizes. If the output power reading does not change significantly for a long time, it indicates that the power stability of the simulator meets the test requirements.

8. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The method for testing the operating wavelength of the lidar echo signal simulator is: Set the working mode of the wavelength meter to pulse mode, set the output power of the simulator to below the maximum allowable power of the wavelength meter, use a signal generator to trigger the simulator to work, and the wavelength meter collects the output signal of the simulator to measure the working wavelength of the lidar echo signal simulator.

9. The method and apparatus for testing performance parameters of a laser radar echo signal simulator according to claim 2, wherein: The simulator position adjustment device's function and working method are as follows: the simulator is placed on an adjustment stand that can move on a guide rail. The motor driver is turned on and driven to adjust the simulator's position so that the simulator's exit pupil coincides with the entrance pupil of the measuring device's focusing lens. After measuring a certain parameter, the motor is driven to drive the adjustment stand and simulator to slide on the guide rail, changing the simulator's X-axis coordinates. The simulator is then moved to the designated test device, and the motor is used to adjust the simulator's Y- and Z-axis coordinates to ensure that the simulator's exit pupil coincides with the entrance pupil of the measuring device's focusing lens. The corresponding simulator performance parameter test is then performed.

Images