Laser radar detection system for multi-dimensional performance calibration

Abstract

The invention discloses a laser radar detection system for multi-dimensional performance calibration, and the system comprises a light source module, a light source coupling module, an optical attribute adjustment module, a detection module adjustment module, and a data collection and processing module. The technical problems that in the prior art, the performance calibration precision of a detection module is insufficient, and the multi-channel consistency is difficult to guarantee are solved. Receiving uniformity quantitative evaluation is achieved through light spot position scanning, consistency adjustment of a gain curve is optimized in combination with a fitting formula, and polarization response performance is comprehensively analyzed through multi-angle polaroid adjustment in combination with a calculation formula. According to the system, a calibration process is preposed from a complete machine level to a detection module level, a full-link and multi-dimensional performance calibration scheme is formed, the calibration precision is improved, and the debugging complexity and the maintenance cost of the complete machine are greatly reduced. Especially, performance consistency screening and polarization sensitivity full-angle coverage of the multi-channel detection module are achieved, and the detection precision and reliability of the laser radar are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar detection system with multi-dimensional performance calibration. Background Art

[0002] As a high-precision measurement device based on optical detection technology, LiDAR is widely used in fields such as meteorological monitoring, environmental detection and autonomous driving. In the prior art, in order to realize the calibration of LiDAR detection modules, the whole machine calibration method is usually adopted, that is, the performance of the whole machine is uniformly tested and adjusted after the radar system is assembled. The main advantage of this method is centralized operation, but there are also the following obvious technical problems: 1. Insufficient calibration accuracy: It is difficult to conduct detailed evaluation of the individual performance of the detection module during the calibration of the whole device, especially in terms of reception uniformity and polarization sensitivity. Calibration is often limited to the adjustment of overall parameters and has limited accuracy.

[0003] 2. Multi-channel consistency is difficult to ensure: The slight differences in the performance of multiple detection channels in the LiDAR system will accumulate and amplify, resulting in inconsistency in the output data of the entire machine, and the calibration of the entire machine cannot effectively solve these difference problems.

[0004] 3. High maintenance cost: The whole-machine calibration method focuses the calibration issues on the system integration stage. If there are performance problems with the detection module, it often needs to be reworked and replaced, resulting in a significant increase in maintenance costs and time costs.

[0005] In order to cope with the limitations of whole-machine calibration, the industry has proposed a modular calibration method, that is, to perform performance testing and adjustments on the detection module separately before assembly. However, this method still has the following shortcomings: For example, modular calibration lacks a systematic solution, and usually only adjusts a single performance (such as gain curve or polarization sensitivity), making it difficult to achieve comprehensive calibration of multi-dimensional performance; the data is highly isolated, the correlation between different calibration parameters has not been effectively verified, and the global consistency of the calibration results is difficult to guarantee; the calibration efficiency is low, the calibration process relies on manual intervention, and lacks intelligent and automated means, which easily leads to error accumulation and reduced efficiency.

[0006] Therefore, how to calibrate the multi-dimensional performance of the detection module and provide a solution that can comprehensively optimize the receiving uniformity, gain curve and polarization sensitivity while improving the calibration efficiency and reducing the maintenance cost has become a technical problem to be solved by the present invention. Summary of the invention

[0007] The technical problem solved by the present invention is to provide a laser radar detection system with multi-dimensional performance calibration in response to the defects existing in the above-mentioned prior art, so as to solve the problems of insufficient calibration accuracy, difficulty in ensuring multi-channel consistency and high maintenance cost raised in the above-mentioned background technology.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A multi-dimensional performance calibrated laser radar detection system, comprising: A light source module, used to provide the light beam required for testing; A light source coupling module, connected to the light source module, for guiding the light beam into the optical fiber and homogenizing the light beam; An optical property adjustment module, connected to the light source coupling module, for adjusting the wavelength, polarization direction and intensity of the light beam to meet the calibration requirements of the detection module; A detection module adjustment module, comprising a clamping module and a power supply module, wherein the clamping module is used to adjust the receiving position and angle of the detection module, and the power supply module is used to provide an adjustable voltage signal to control the gain of the detection module; A data acquisition and processing module is connected to the detection module adjustment module, and is used to receive the signal output by the detection module, and to generate a calibration result by processing the signal intensity, gain change curve and polarization direction response data; The detection module adjustment module and the data acquisition and processing module cooperate to implement the reception uniformity test, gain curve calibration and polarization sensitivity analysis of the detection module, which specifically includes: For the calibration of receiving uniformity, the light spot position is adjusted to cover multiple points on the receiving surface of the detection module, the signal strength value is recorded and the intensity difference between each point is compared; The gain curve is calibrated by adjusting the voltage signal of the power supply module, recording the signal amplification of the detection module at different gain voltages, and matching the channel consistency; The polarization sensitivity is calibrated by adjusting the polarization direction of the optical property adjustment module, measuring the response values ​​of the detection module to different polarization directions, and analyzing the deviation.

[0009] As a further solution of the present invention, the data acquisition and processing module analyzes and processes the calibration data using the following algorithm: For the calibration of reception uniformity, the following formula is used to quantify the uniformity of the signal strength on the receiving surface of the detection module: in, and They are the maximum and minimum signal strengths at multiple test points on the receiving surface, is the relative difference of receiving uniformity; The calibration of the gain curve is based on the following gain model fitting formula: in, It represents the functional relationship between gain ratio and voltage. is the gain amplification factor, It is the voltage nonlinear influence index, and the gain consistency calibration is achieved by fitting the gain curves of different channels; The polarization sensitivity calibration is based on the following formula to calculate the polarization response difference of the detection module: in, and They are the signal strength of the detection module at 0° and 90° polarization directions, is the relative difference in polarization sensitivity.

[0010] As a further solution of the present invention, the light source module includes a halogen tungsten lamp, an LED lamp or a krypton lamp, and has the function of linearly adjusting the luminous intensity; the light source coupling module includes a coupling lens and an optical fiber, and the optical fiber is used to homogenize the light source and shape it into a desired beam shape through a collimating lens.

[0011] As a further solution of the present invention, the data acquisition and processing module is used to generate a receiving uniformity test curve, a gain voltage change curve and a polarization sensitivity data spectrum based on the multi-dimensional calibration results.

[0012] As a further solution of the present invention, the receiving uniformity calibration is implemented by the following steps: Step 1, adjusting the light spot position to cover multiple points on the receiving surface of the detection module; Step 2, record the signal strength values ​​at different points; Step 3: Calculate the intensity difference between each point to evaluate the reception uniformity.

[0013] As a further solution of the present invention, the gain curve calibration is achieved by the following steps: Step 1, adjusting the luminous intensity of the light source module so that the detection module generates a detectable initial signal amplitude at the lowest gain voltage; Step 2, gradually increase the gain voltage from the lowest gain voltage, record the output signal amplification factor of the detection module each time it increases, and draw a gain voltage curve; Step 3, for multiple channels, draw gain curves respectively, and achieve consistency of output amplification of each channel at a target gain voltage by adjusting the gain voltage or light source attenuator of each channel; Step 4: Use the fitting formula Perform mathematical fitting on the gain curve of each channel and ensure the consistency of the gain curve of each channel by comparing the differences in fitting parameters.

[0014] As a further solution of the present invention, the polarization sensitivity calibration is achieved by the following steps: Step 1, inserting a linear polarizer into the light property adjustment module, wherein the polarizer is mounted on a rotatable bracket and the polarization angle is adjusted around the propagation direction of the light beam; Step 2, adjust the angle of the polarizer so that the polarization directions are set to 0°, 45°, 90° and 135° respectively; Step 3: Record the signal response values ​​of the detection module under the above polarization directions respectively. , , and ; Step 4: Calculate the deviation between signals in different polarization directions: Step 5: Compare polarization sensitivity indicators and If the deviation value is within the preset threshold range, it is evaluated that the polarization performance of the detection module meets the design requirements.

[0015] As a further solution of the present invention, the light source coupling module includes an optical fiber, which is used to homogenize the light spot and is shaped into a homogenized test light spot through a collimating lens. The diameter of the homogenized light spot is between 0.8 and 5 mm.

[0016] As a further solution of the present invention, the detection module includes a photomultiplier tube or a single photon detector for measuring the intensity and polarization characteristics of the adjusted optical signal.

[0017] As a further solution of the present invention, the light source module, the light source coupling module, the light property adjustment module and the detection module work together to achieve performance calibration of the detection module through the following steps: Step 1, using a light source module to generate a test beam, and homogenizing the light spot through the optical fiber and collimating lens of the light source coupling module; Step 2, adjusting the wavelength, polarization direction and energy intensity of the light beam through filters and polarizers in the light property adjustment module; Step 3: direct the adjusted light beam into the detection module, and record the signal intensity, gain curve, and polarization sensitivity through the response of the detection module.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The multi-dimensional performance calibration is refined to the detection module level, completely getting rid of the dependence on the calibration of the traditional lidar whole machine. Through the coordinated design of the light source module, the light property adjustment module and the detection module adjustment module, the independent screening, calibration and performance optimization of the detection module are realized. Especially in the calibration of gain curve and polarization sensitivity, a new method based on mathematical fitting and quantitative calculation is proposed, which significantly improves the calibration accuracy and module consistency.

[0019] 2. Through deep integration between modules, innovative multi-dimensional calibration of reception uniformity, gain curve and polarization sensitivity is achieved. This solution can not only provide higher-precision detection modules for lidar manufacturing, but also put calibration issues in advance to the module production stage, greatly reducing the debugging complexity and maintenance costs after the whole machine is integrated.

[0020] 3. By optimizing the signal basis of receiving uniformity calibration, combined with the channel consistency adjustment of gain curve calibration and the quantitative analysis of polarization sensitivity calibration, the present invention successfully achieves the improvement of the full link performance from light source to detection module. In particular, the consistency screening of multi-channel detection modules solves the technical problem of ensuring the consistency of signals in different channels in the prior art, and greatly improves the overall quality of detection data and system reliability. 4. A full-link, multi-dimensional performance calibration solution has been formed to solve the pain point that existing technologies cannot systematically implement calibration: by scanning the spot position, combined with the formula The quantitative evaluation of the optical signal distribution on the detection surface is realized, providing a high-precision basis for subsequent optimization; Gain curve calibration: through the fitting formula , not only the single channel gain is optimized, but also the fitting parameters are compared. and , which solves the long-standing technical problem of inconsistent gain among multiple channels and ensures the consistency of channel output; polarization sensitivity calibration: using multi-angle polarizers to adjust the direction of the input beam, combined with the formula and , comprehensively analyzing the response performance of the detection module under different polarization directions, thus achieving quantification and full-angle coverage in polarization calibration for the first time.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 It is a schematic diagram of the overall structure of the laser radar detection system of the present invention.

[0025] Figure 3 This is a schematic diagram of the light source coupling module and light spot generation of the present invention.

[0026] Figure 4 This is a comparison chart of the calibration results of the present invention and multi-channel consistency. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1 —4. In an embodiment of the present invention, a multi-dimensional performance calibrated laser radar detection system includes: A light source module, used to provide the light beam required for testing; A light source coupling module, connected to the light source module, for guiding the light beam into the optical fiber and homogenizing the light beam; An optical property adjustment module, connected to the light source coupling module, for adjusting the wavelength, polarization direction and intensity of the light beam to meet the calibration requirements of the detection module; A detection module adjustment module, comprising a clamping module and a power supply module, wherein the clamping module is used to adjust the receiving position and angle of the detection module, and the power supply module is used to provide an adjustable voltage signal to control the gain of the detection module; A data acquisition and processing module is connected to the detection module adjustment module, and is used to receive the signal output by the detection module, and to generate a calibration result by processing the signal intensity, gain change curve and polarization direction response data; The detection module adjustment module and the data acquisition and processing module cooperate to implement the reception uniformity test, gain curve calibration and polarization sensitivity analysis of the detection module, which specifically includes: For the calibration of receiving uniformity, the light spot position is adjusted to cover multiple points on the receiving surface of the detection module, the signal strength value is recorded and the intensity difference between each point is compared; The gain curve is calibrated by adjusting the voltage signal of the power supply module, recording the signal amplification of the detection module at different gain voltages, and matching the channel consistency; The polarization sensitivity is calibrated by adjusting the polarization direction of the optical property adjustment module, measuring the response values ​​of the detection module to different polarization directions, and analyzing the deviation.

[0029] As a further solution of the present invention, the data acquisition and processing module analyzes and processes the calibration data using the following algorithm: For the calibration of reception uniformity, the following formula is used to quantify the uniformity of the signal strength on the receiving surface of the detection module: in, and They are the maximum and minimum signal strengths at multiple test points on the receiving surface, is the relative difference of receiving uniformity; The calibration of the gain curve is based on the following gain model fitting formula: in, It represents the functional relationship between gain ratio and voltage. is the gain amplification factor, It is the voltage nonlinear influence index, and the gain consistency calibration is achieved by fitting the gain curves of different channels; The polarization sensitivity calibration is based on the following formula to calculate the polarization response difference of the detection module: in, and They are the signal strength of the detection module at 0° and 90° polarization directions, is the relative difference in polarization sensitivity.

[0030] The light source module includes a halogen tungsten lamp, an LED lamp or a krypton lamp, and has the function of linearly adjusting the luminous intensity; the light source coupling module includes a coupling lens and an optical fiber, and the optical fiber is used to homogenize the light source and shape it into the required beam shape through a collimating lens; the data acquisition and processing module is used to generate a receiving uniformity test curve, a gain voltage change curve and a polarization sensitivity data spectrum based on the multi-dimensional calibration results.

[0031] As a further solution of the present invention, the receiving uniformity calibration is implemented by the following steps: Step 1, adjusting the light spot position to cover multiple points on the receiving surface of the detection module; Step 2, record the signal strength values ​​at different points; Step 3: Calculate the intensity difference between each point to evaluate the reception uniformity.

[0032] As a further solution of the present invention, the gain curve calibration is achieved by the following steps: Step 1, adjusting the luminous intensity of the light source module so that the detection module generates a detectable initial signal amplitude at the lowest gain voltage; Step 2, gradually increase the gain voltage from the lowest gain voltage, record the output signal amplification factor of the detection module each time it increases, and draw a gain voltage curve; Step 3, for multiple channels, draw gain curves respectively, and achieve consistency of output amplification of each channel at a target gain voltage by adjusting the gain voltage or light source attenuator of each channel; Step 4: Use the fitting formula Perform mathematical fitting on the gain curve of each channel and ensure the consistency of the gain curve of each channel by comparing the differences in fitting parameters.

[0033] As a further solution of the present invention, the polarization sensitivity calibration is achieved by the following steps: Step 1, inserting a linear polarizer into the light property adjustment module, wherein the polarizer is mounted on a rotatable bracket and the polarization angle is adjusted around the propagation direction of the light beam; Step 2, adjust the angle of the polarizer so that the polarization directions are set to 0°, 45°, 90° and 135° respectively; Step 3: Record the signal response values ​​of the detection module under the above polarization directions respectively. , , and ; Step 4: Calculate the deviation between signals in different polarization directions: Step 5: Compare polarization sensitivity indicators and If the deviation value is within the preset threshold range, it is evaluated that the polarization performance of the detection module meets the design requirements.

[0034] The light source coupling module includes an optical fiber, which is used to homogenize the light spot and is shaped into a homogenized test light spot through a collimating lens. The diameter of the homogenized light spot is between 0.8 and 5 mm. The detection module includes a photomultiplier tube or a single-photon detector, which is used to measure the intensity and polarization characteristics of the adjusted light signal.

[0035] As a further solution of the present invention, the light source module, the light source coupling module, the light property adjustment module and the detection module work together to achieve performance calibration of the detection module through the following steps: Step 1, using a light source module to generate a test beam, and homogenizing the light spot through the optical fiber and collimating lens of the light source coupling module; Step 2, adjusting the wavelength, polarization direction and energy intensity of the light beam through filters and polarizers in the light property adjustment module; Step 3: direct the adjusted light beam into the detection module, and record the signal intensity, gain curve, and polarization sensitivity through the response of the detection module.

[0036] Embodiment 1: See also Figure 1The present invention consists of four parts: a light source module, a light source coupling module, a light property adjustment module, and a detection module adjustment module. Figure 1 As shown, the calibration module consists of four parts, namely, a light source module, a light source coupling module, a light property adjustment module and a detection device adjustment module. The light source module 101 provides the light source required for the test, which is received by the coupling lens 102 in the light source coupling module and coupled into the optical fiber 103. Through the homogenization effect of the optical fiber, the light source derived therefrom is collimated by the collimating lens 104, and the uniformity deviation meets the design requirements. The collimated light source passes through the light property adjustment module 105, which contains adjustment devices such as wavelength, polarization, and energy, and can adjust the light properties to the required requirements. The adjusted light beam enters the detector 106, and the power supply and movement control of the detection device are completed by the clamping module 107.

[0037] The following are the descriptions of each component: 1) Light source module: The light source module can be composed of halogen tungsten lamps, LED lamps, krypton lamps and other light sources, and has the function of linearly adjusting the luminous intensity; 2) Coupling lens: a lens that converges the light beam, usually a plano-convex lens. The lens size and focal length selection are related to the fiber NA angle; 3) Optical fiber: Conventional optical fiber has basically no attenuation for light beams from 300 to 1200nm, and can fully homogenize the received light spot. The core diameter and NA angle of the optical fiber need to match the front and rear end lenses; 4) Collimating lens: Similar to the coupling lens, the diameter and divergence angle of the collimated light spot can be adjusted according to the selected focal length; 5) Optical property adjustment module: used to load different optical lenses. By replacing different optical lenses, the wavelength selection, polarization adjustment and energy attenuation of the light beam can be completed, so that the output light beam meets the test requirements 6) Detection device: The detection device used in the laser radar equipment can be a photomultiplier tube PMT or a single photon detector SAPD; 7) Clamping module: This module includes a power supply and mechanical movement adjustment module. After the detector is fixed in the clamping module, the optical path receiving position can be adjusted through the clamping module, and the performance parameter adjustment and calibration of the detector can be completed through the power supply module; The components work as follows: The light source module emits a test beam, which is focused at the optical fiber receiving end through a coupling lens, transmitted through the optical fiber, and shaped by a collimating lens at the optical fiber output end. The shaped test beam enters the optical property adjustment module, and according to the test requirements, different optical lenses are selected to adjust parameters such as wavelength, polarization, and intensity. Finally, the beam enters the detection device, and the position of the detection device can be adjusted through the clamping module to meet the required test requirements.

[0038] Uniformity test of the detection surface of the detection device: The light source module emits a test beam, which is focused on the receiving end of the optical fiber through a coupling lens, transmitted through the optical fiber, and shaped by a collimating lens at the output end of the optical fiber. The diameter of the shaped light spot is between 0.8 and 1 mm. The light spot passes through the light property adjustment module. According to the requirements of the laser radar channel, a suitable narrow-band filter is selected to filter out unnecessary band parts. The light spot is adjusted to the center of the detector through the clamping module. At this position, the intensity curves in four directions are tested at intervals of 0.5 mm. By determining the relative difference of the four curves at different positions, the uniformity of the detector receiving surface is confirmed to determine whether the detector can be used in the laser radar.

[0039] Detector gain curve test: The light source module emits a test beam, which is focused on the optical fiber receiving end through a coupling lens, transmitted through the optical fiber, and shaped by a collimating lens at the optical fiber output end. The diameter of the shaped light spot is between 4 and 5 mm. The light spot passes through the optical property adjustment module. According to the requirements of the laser radar channel, a suitable narrowband filter is selected to filter out unnecessary band parts. Through the attenuation configuration, the signal amplitude is adjusted to the appropriate position at the lowest gain position. Through the adjustment interval of 0.01V, the signal gain ratio under different gain voltages is recorded. Under dual-channel matching, the curve is recorded and calibrated to the same signal amplification ratio to achieve relatively consistent absolute intensity measurement requirements.

[0040] Detector polarization difference test: The light source module emits a test beam, which is focused on the optical fiber receiving end through a coupling lens, transmitted through the optical fiber, and shaped by a collimating lens at the optical fiber output end. The diameter of the shaped light spot is between 4 and 5 mm. The light spot passes through the light property adjustment module. According to the requirements of the laser radar channel, a suitable narrow-band filter is selected to filter out unnecessary band parts, and a linear polarizer is added to adjust the polarization direction to the specified position. The signal amplitude of the detector output is measured, and the detector is rotated 90 degrees through the clamping module. The signal amplitude of the detector output is measured again, and the polarization difference of the detector is confirmed based on the deviation values ​​of the two measurements.

[0041] Embodiment 2: In environmental pollution source monitoring, LiDAR is widely used for emission monitoring and distribution mapping of atmospheric pollutants. Its detection accuracy directly affects the accuracy of pollution source identification and the reliability of pollution diffusion models. However, due to the limitations of the prior art, the performance calibration of LiDAR detection modules often relies on the calibration of the entire machine. This method makes it difficult to comprehensively evaluate the performance consistency and response characteristics of a single detection module, and easily leads to the accumulation of deviations in multi-channel data. The present invention provides a modular calibration method, which significantly improves the calibration efficiency and data accuracy through independent performance analysis and calibration of detection modules.

[0042] In the environmental pollution source monitoring project, the laser radar needs to monitor the aerosol distribution, sulfur dioxide, nitrogen oxides and other pollutants in the atmosphere in real time for a long time. The present invention completes the performance calibration of the detection module through the following specific steps: 1. Receiving uniformity calibration: Based on the optical absorption characteristics of various atmospheric pollutants, a narrowband light beam is generated using a light source module, and a light beam of the target wavelength is selected through the light property adjustment module. The light beam is projected onto the receiving surface of the detection module, and the signal intensity of each point is recorded using the data acquisition and processing module. The optical signal uniformity of the receiving surface is quantified through multi-point coverage of the light spot position. This step effectively improves the module's response accuracy to the receiving surface, ensures the consistency of the optical input of subsequent calibration, and avoids the signal fluctuation problem caused by light spot deviation in traditional technologies.

[0043] 2. Gain curve calibration: During the calibration process, adjust the light source intensity so that the detection module produces a detectable initial signal amplitude. Then gradually increase the gain voltage of the detection module and record the signal amplification factor at different voltages. Analyze the gain curve characteristics of the module through the fitting formula, and adjust the voltage of the power supply module and the intensity of the light source module to ensure that each channel outputs a consistent amplification factor at the target gain point. This calibration link ensures the signal consistency of the multi-channel detection module and effectively solves the error accumulation problem of multi-channel data in pollution source monitoring.

[0044] 3. Polarization sensitivity calibration: In polarization sensitivity calibration, based on the polarization scattering characteristics of aerosols and pollutant particles, a light property adjustment module is used to insert a polarizer, and the polarization direction is adjusted to generate a linear polarized light beam. After the detection module receives light beams in different polarization directions, it records its signal output value and compares and analyzes the response differences under 0° and 90° polarization directions. By adjusting the detection module parameters, its polarization direction sensitivity response is optimized. Polarization calibration achieves full-angle coverage and quantitative analysis, providing basic data support for the accurate monitoring of different types of pollutants.

[0045] 4. Adaptability test under complex environmental conditions: To verify the adaptability of the detection module in the actual environment, the operation scenarios under different pollutant concentrations and environmental temperature and humidity conditions were simulated. A stable test beam was generated by adjusting the light intensity output of the light source module and the energy control module of the light property adjustment module. The reception uniformity and gain curve of the detection module under different pollutant concentrations and meteorological conditions were tested multiple times to ensure its performance stability in complex environments. This link ensures the reliability of the module in different monitoring scenarios and significantly reduces the data deviation caused by environmental changes.

[0046] Embodiment 3: In meteorological monitoring, lidar is widely used to obtain key data such as atmospheric aerosol distribution, water vapor concentration, and temperature and humidity parameters. Its detection accuracy directly affects the reliability of environmental monitoring. However, due to the limitations of the existing technology, the performance calibration of radar detection modules often relies on the calibration of the entire machine. This method is difficult to comprehensively evaluate the performance consistency and response characteristics of a single detection module, and easily leads to the accumulation of deviations in multi-channel data. The present invention provides a modular calibration method, which significantly improves the calibration efficiency and data accuracy through independent performance analysis and calibration of detection modules.

[0047] In environmental monitoring projects, it is necessary to monitor the distribution of aerosols and water vapor changes in the atmosphere in real time for a long time. The present invention completes the performance calibration of the detection module through the following specific steps: For the detection of water vapor content in the atmosphere, a light source module is used to generate a narrowband light beam that matches the radar water vapor Raman channel, and the target wavelength light beam is selected through the filter in the optical property adjustment module. After the light beam is projected onto the detection module, the data acquisition module is used to record the signal response at different gain voltages. By fitting the gain curve, the differences in the gain parameters of each channel are analyzed, and the power supply module is dynamically adjusted to ensure the consistency of the signal output of each channel at the target gain point. The signal amplification consistency of the multi-channel water vapor detection module is achieved, which significantly reduces the multi-channel data error and provides a reliable guarantee for high-precision water vapor distribution detection.

[0048] In the polarization sensitivity calibration, according to the polarization scattering characteristics of aerosols, the optical property adjustment module is used to insert the polarizer, and the polarization direction is adjusted to generate a linear polarized light beam. After the detection module receives light beams with different polarization directions, its signal output value is recorded, and the response difference under the polarization directions of 0° and 90° is compared and analyzed. The sensitivity response in the polarization direction is optimized by adjusting the detection module parameters. The sensitivity consistency of the detection module to signals in different polarization directions is enhanced, the detection accuracy of aerosol polarization scattering information is improved, and higher quality data is provided for environmental pollution source tracing and sandstorm weather monitoring.

[0049] In order to verify the adaptability of the detection module in the actual environment, the operation scenarios under different temperature and humidity conditions were simulated. A stable test beam was generated by adjusting the light intensity output of the light source module and the energy control module of the light property adjustment module. Under the conditions of temperature and humidity changes, the receiving uniformity and gain curve of the detection module were tested multiple times, and the calibration data under extreme conditions were recorded. Ensuring the performance stability of the detection module in a complex environment lays the foundation for the long-term operation of the all-weather atmospheric monitoring equipment, while avoiding data distortion caused by environmental changes.

[0050] After calibration, the detection module was installed in the lidar system and used to monitor the aerosol distribution and water vapor changes of the project in real time. The reliability and consistency of the calibration module were verified through retrospective analysis of the monitoring data, showing that the error of multi-channel data was reduced by more than 20% compared with the traditional calibration method, and the sensitivity of polarization scattering signal detection was increased by more than 15%. The calibration results are directly reflected in the improvement of data quality and the stability of equipment operation.

[0051] In the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "setting", "connection", "fixation", "screw-on" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0052] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A multi-dimensional performance calibrated laser radar detection system, characterized in that: include: A light source module, used to provide the light beam required for the test; A light source coupling module, connected to the light source module, for guiding the light beam into the optical fiber and homogenizing the light beam; An optical property adjustment module, connected to the light source coupling module, for adjusting the wavelength, polarization direction and intensity of the light beam to meet the calibration requirements of the detection module; A detection module adjustment module, comprising a clamping module and a power supply module, wherein the clamping module is used to adjust the receiving position and angle of the detection module, and the power supply module is used to provide an adjustable voltage signal to control the gain of the detection module; A data acquisition and processing module is connected to the detection module adjustment module, and is used to receive the signal output by the detection module, and to generate a calibration result by processing the signal intensity, gain change curve and polarization direction response data; The detection module adjustment module and the data acquisition and processing module cooperate to implement the reception uniformity test, gain curve calibration and polarization sensitivity analysis of the detection module, which specifically includes: For the calibration of receiving uniformity, the light spot position is adjusted to cover multiple points on the receiving surface of the detection module, the signal strength value is recorded and the intensity difference between each point is compared; The gain curve is calibrated by adjusting the voltage signal of the power supply module, recording the signal amplification of the detection module at different gain voltages, and matching the channel consistency; The polarization sensitivity is calibrated by adjusting the polarization direction of the optical property adjustment module, measuring the response values ​​of the detection module to different polarization directions, and analyzing the deviation.

2. A multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: in, The data acquisition and processing module analyzes and processes the calibration data through the following algorithms: For the calibration of reception uniformity, the following formula is used to quantify the uniformity of the signal strength on the receiving surface of the detection module: in, and They are the maximum and minimum signal strengths at multiple test points on the receiving surface, is the relative difference of receiving uniformity; The calibration of the gain curve is based on the following gain model fitting formula: in, It represents the functional relationship between gain ratio and voltage. is the gain amplification factor, It is the voltage nonlinear influence index, and the gain consistency calibration is achieved by fitting the gain curves of different channels; The polarization sensitivity calibration is based on the following formula to calculate the polarization response difference of the detection module: in, and They are the signal strength of the detection module at 0° and 90° polarization directions, is the relative difference in polarization sensitivity.

3. A multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The light source module includes a halogen tungsten lamp, an LED lamp or a krypton lamp, and has the function of linearly adjusting the luminous intensity; the light source coupling module includes a coupling lens and an optical fiber, and the optical fiber is used to homogenize the light source and shape it into a desired light beam shape through a collimating lens.

4. A multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The data acquisition and processing module is used to generate a receiving uniformity test curve, a gain voltage change curve and a polarization sensitivity data spectrum based on the multi-dimensional calibration result.

5. The multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The receiving uniformity calibration is achieved by the following steps: Step 1, adjusting the light spot position to cover multiple points on the receiving surface of the detection module; Step 2, record the signal strength values ​​at different points; Step 3: Calculate the intensity difference between each point to evaluate the reception uniformity.

6. The multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The gain curve calibration is achieved by the following steps: Step 1, adjusting the luminous intensity of the light source module so that the detection module generates a detectable initial signal amplitude at the lowest gain voltage; Step 2, gradually increase the gain voltage from the lowest gain voltage, record the output signal amplification factor of the detection module each time it increases, and draw a gain voltage curve; Step 3, for multiple channels, draw gain curves respectively, and achieve consistency of output amplification of each channel at a target gain voltage by adjusting the gain voltage or light source attenuator of each channel; Step 4: Use the fitting formula Perform mathematical fitting on the gain curve of each channel and ensure the consistency of the gain curve of each channel by comparing the differences in fitting parameters.

7. The multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The polarization sensitivity calibration is achieved by the following steps: Step 1, inserting a linear polarizer into the light property adjustment module, wherein the polarizer is mounted on a rotatable bracket and the polarization angle is adjusted around the propagation direction of the light beam; Step 2, adjust the angle of the polarizer so that the polarization directions are set to 0°, 45°, 90° and 135° respectively; Step 3: Record the signal response values ​​of the detection module under the above polarization directions respectively. , , and ; Step 4: Calculate the deviation between signals in different polarization directions: Step 5: Compare polarization sensitivity indicators and If the deviation value is within the preset threshold range, it is evaluated that the polarization performance of the detection module meets the design requirements.

8. The multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The light source coupling module comprises an optical fiber, which is used to homogenize the light spot and is shaped into a homogenized test light spot through a collimating lens. The diameter of the homogenized light spot is between 0.8 and 5 mm.

9. The multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The detection module includes a photomultiplier tube or a single photon detector, which is used to measure the intensity and polarization characteristics of the adjusted optical signal.

10. The multi-dimensional performance calibrated laser radar detection system according to claim 1, characterized in that: The light source module, light source coupling module, light property adjustment module and detection module work together to achieve performance calibration of the detection module through the following steps: Step 1, using a light source module to generate a test beam, and homogenizing the light spot through the optical fiber and collimating lens of the light source coupling module; Step 2, adjusting the wavelength, polarization direction and energy intensity of the light beam through filters and polarizers in the light property adjustment module; Step 3: direct the adjusted light beam into the detection module, and record the signal intensity, gain curve, and polarization sensitivity through the response of the detection module.

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