Coherent wind lidar calibration system and method

Abstract

The invention relates to the technical field of laser radar calibration, and discloses a coherent wind lidar calibration system and method. Comprising a wind field, an atmosphere scene and calibrated coherent wind finding radar parameter input module, a wind field mapping module, an atmosphere scene simulation module, a radial frequency profile correction module, a radial amplitude profile correction module and an atmosphere scene output module. A wind field, an atmosphere scene and calibrated coherent wind finding radar parameters are input into the module, the wind field mapping module and the atmosphere scene simulation module are used for simulating the wind field and the atmosphere scene, and frequency and amplitude errors of signals generated by the coherent wind finding laser radar calibrator are corrected. And after the correction is finished, an analog signal is output and modulated by the coherent wind lidar calibrator, a modulated optical signal is coupled into the detected coherent wind lidar, and wind field data inverted by the detected lidar is compared with preset wind field data, so that the detected coherent wind lidar can be calibrated.

Description

Technical Field

[0001] The present invention relates to the technical field of laser radar calibration, and in particular to a coherent wind measurement laser radar calibration system and method. Background Art

[0002] Currently, the calibration of coherent wind lidar requires the use of a wind meteorological tower or wind cup. The calibration process is greatly affected by the natural wind field and requires waiting for the appropriate wind speed and direction. It is difficult to carry out at any time and place and requires long-term observation. The site requirements are high and the calibration cost is high.

[0003] The current calibration of coherent wind lidar has problems such as strong dependence on calibration weather conditions, high time cost, incomplete wind speed coverage and insufficient results. It is difficult to meet the needs of coherent wind lidar for fast, accurate and comprehensive calibration. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a coherent wind laser radar calibration system and method, which solves the problems raised in the above background technology.

[0005] To solve the above technical problems, according to one aspect of the present invention, more specifically, a coherent wind laser radar calibration system includes a wind field, an atmospheric scene, and a calibrated coherent wind radar parameter input module, a wind field mapping module, an atmospheric scene simulation module, a radial frequency profile correction module, a radial amplitude profile correction module, and an atmospheric scene output module;

[0006] Wind field, atmospheric scene and calibrated coherent wind radar parameter input module: that is, the interactive module, through which the wind field, atmospheric scene settings and the measured radar measurement mode and telescope angle are input;

[0007] Wind field mapping module: used to convert three-dimensional wind field information into radial information corresponding to the laser radar measurement mode under test, and perform radial mapping of the wind field;

[0008] Atmospheric scene simulation module: used to simulate different atmospheric scenes, including the spatial and temporal distribution of three-dimensional wind fields and aerosols;

[0009] Radial frequency profile correction module: used to correct the frequency error of the signal generated by the coherent wind lidar calibration instrument;

[0010] Radial amplitude profile correction module: used to correct the amplitude error of the signal generated by the coherent wind lidar calibration instrument;

[0011] Atmospheric scene output module: used to output the simulated wind speed information and profile frequency information calculated in the wind field mapping module to the control circuit of the calibration system, and then the control circuit drives the acousto-optic frequency shifter to modulate the laser echo signal with wind field information and aerosol information through the frequency shifter.

[0012] Furthermore, the wind field mapping method of the wind field mapping module is:

[0013] The first step is to convert the wind field information into the profile radial wind speed information according to the wind speed and wind direction angle of the three-dimensional wind field, the working mode of the measured laser radar and the telescope angle, as shown in the formula:

[0014]

[0015] Among them, V Los is the calculated radial wind speed of the radar telescope under test, V h is the set horizontal wind speed, θ is the set wind direction angle, φ is the horizontal angle of the radar telescope under test, and α is the angle between the radar telescope under test and the horizontal plane;

[0016] The second step is to divide the profile radial wind speed information into multiple single range gate radial wind speed information by range gate segmentation.

[0017] The third step is to modulate the radial wind speed of the single range gate by analog signal and convert it into the radial frequency / spectrum information of the single range gate:

[0018] f d =2V Los / λ

[0019] Among them, f d is the calculated Doppler shift, λ is the wavelength of light;

[0020] The fourth step is to reconstruct the profile of the calculated single range gate frequency / spectrum information according to the range gate segmentation order and reconstruct it into a profile echo signal.

[0021] Furthermore, the radial frequency profile correction module tests the amplitude response of the signal generated by the coherent wind laser radar calibration instrument, and after obtaining the frequency error curve generated by the test, the system performs a linear fit of y=ax+b on it to correct the error frequency to the accurate frequency.

[0022] Furthermore, the radial amplitude profile correction module tests the amplitude response of the signal generated by the coherent wind laser radar calibration instrument, and performs inverse function calculation on the obtained curve to correct the generated amplitude error.

[0023] A coherent wind laser radar calibration method is implemented based on the above-mentioned coherent wind laser radar calibration system, and specifically includes the following steps:

[0024] S1. Select the system preset wind field or the custom wind field scene; select the system preset aerosol scene or the custom aerosol scene; input the measurement mode of the radar under test and the telescope angle for subsequent wind field mapping;

[0025] S2. Perform wind field mapping according to the parameters set in the steps through a wind field mapping module;

[0026] S3, performing a linear fit of y=ax+b on the measured value and theoretical value of the frequency shifter shift frequency, and correcting the error frequency to the accurate frequency;

[0027] S4. Based on the wind speed projection and laser radar equation, as well as the radial amplitude profile correction module and the frequency and amplitude corrected by the radial amplitude profile correction module, simulate the radial wind speed in any direction of the atmospheric wind field, and calibrate the three-dimensional wind field reconstruction system of the laser radar under test, wherein the number of profiles of the radial wind speed in any direction is based on the needs of the three-dimensional wind field reconstruction system of the laser radar under test and the actual use of the laser radar;

[0028] S5. The signal containing the wind field is input into the coherent wind measuring laser radar under test through calculation by the calibrator, and the wind field signal is then inverted by the laser radar under test. The signals of the two wind fields are compared, thereby realizing the quantitative calibration of the coherent wind measuring laser radar under test.

[0029] The beneficial effects of the coherent wind laser radar calibration system and method of the present invention are:

[0030] Through this calibration system and method, a reference signal is generated by combining simulated wind field and aerosol characteristics to accurately reproduce the real wind measurement scene and improve the representativeness of the calibration. The system errors in the laser source, receiver and signal processing link are fully compensated to ensure more accurate calibration results. The system does not need to rely on wind cups, meteorological towers or natural wind fields. The calibration is not limited by weather conditions and can be completed anytime and anywhere.

[0031] Through the precise demodulation of Doppler frequency shift in this calibration system, high-precision frequency shift demodulation can be achieved, and the calibration accuracy can reach the sub-meter / second level.

[0032] The system supports calibration of multiple range gates and the full wind speed range, covering the entire range and avoiding the limitations of single-point calibration.

[0033] This system can dynamically adjust radar parameters in real time based on actual measurement data to improve calibration efficiency and accuracy.

[0034] The calibration system and method improve the calibration accuracy and efficiency, reduce the calibration cost, and meet the requirements of coherent wind laser radar for fast, accurate, and comprehensive calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0036] Figure 1 It is a schematic diagram of the process of the present invention.

[0037] Figure 2 Schematic diagram of wind field and atmospheric scene input of the coherent wind laser radar calibration system of the present invention.

[0038] Figure 3 Schematic diagram of the general coherent wind lidar 3D wind field reconstruction process.

[0039] Figure 4 This is a flow chart of the system radial wind speed mapping of the present invention.

[0040] Figure 5 This is a result diagram of the profile calculation of the VAD mode coherent wind laser radar calibration system of the present invention.

[0041] Figure 6 This is a result diagram of the profile calculation of the RHI mode coherent wind laser radar calibration system of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0043] like Figure 1 As shown, according to one aspect of the present invention, a coherent wind laser radar calibration system is provided, comprising a wind field, an atmospheric scene, and a calibrated coherent wind radar parameter input module, a wind field mapping module, an atmospheric scene simulation module, a radial frequency profile correction module, a radial amplitude profile correction module, and an atmospheric scene output module;

[0044] Wind field, atmospheric scene and calibrated coherent wind radar parameter input module: that is, the interactive module, through which the wind field, atmospheric scene settings and the measured radar measurement mode and telescope angle are input;

[0045] Wind field mapping module: used to convert three-dimensional wind field information into radial information corresponding to the laser radar measurement mode under test, and perform radial mapping of the wind field;

[0046] Atmospheric scene simulation module: used to simulate different atmospheric scenes, including the spatial and temporal distribution of three-dimensional wind fields and aerosols;

[0047] Radial frequency profile correction module: used to correct the frequency error of the signal generated by the coherent wind lidar calibration instrument;

[0048] Radial amplitude profile correction module: used to correct the amplitude error of the signal generated by the coherent wind lidar calibration instrument;

[0049] Atmospheric scene output module: used to output the simulated wind speed information and profile frequency information calculated in the wind field mapping module to the control circuit of the calibration system, and then the control circuit drives the acousto-optic frequency shifter to modulate the laser echo signal with wind field information and aerosol information through the frequency shifter.

[0050] In this embodiment, the wind field mapping method of the wind field mapping module is:

[0051] The first step is to convert the wind field information into the profile radial wind speed information according to the wind speed and wind direction angle of the three-dimensional wind field, the working mode of the measured laser radar and the telescope angle, as shown in the formula:

[0052]

[0053] Among them, V Los is the calculated radial wind speed of the radar telescope under test, V h is the set horizontal wind speed, θ is the set wind direction angle, φ is the horizontal angle of the radar telescope under test, and α is the angle between the radar telescope under test and the horizontal plane;

[0054] The second step is to divide the profile radial wind speed information into multiple single range gate radial wind speed information by range gate segmentation.

[0055] The third step is to modulate the radial wind speed of the single range gate by analog signal and convert it into the radial frequency / spectrum information of the single range gate:

[0056] f d =2V Los / λ

[0057] Among them, f d is the calculated Doppler shift, λ is the wavelength of light;

[0058] The fourth step is to reconstruct the profile of the calculated single range gate frequency / spectrum information according to the range gate segmentation order and reconstruct it into a profile echo signal.

[0059] In this embodiment, the radial frequency profile correction module tests the amplitude response of the signal generated by the coherent wind laser radar calibration instrument, and after obtaining the frequency error curve generated by the test, the system performs a linear fit of y=ax+b on it to correct the error frequency to the accurate frequency.

[0060] This embodiment also provides a coherent wind laser radar calibration method, which is implemented based on a coherent wind laser radar calibration system and specifically includes the following steps:

[0061] S1. Select the system preset wind field or the custom wind field scene; select the system preset aerosol scene or the custom aerosol scene; input the measurement mode of the radar under test and the telescope angle for subsequent wind field mapping;

[0062] S2. Perform wind field mapping according to the parameters set in the steps through a wind field mapping module;

[0063] S3, performing a linear fit of y=ax+b on the measured value and theoretical value of the frequency shifter shift frequency, and correcting the error frequency to the accurate frequency;

[0064] S4. Based on the wind speed projection and laser radar equation, as well as the radial amplitude profile correction module and the frequency and amplitude corrected by the radial amplitude profile correction module, simulate the radial wind speed in any direction of the atmospheric wind field, and calibrate the three-dimensional wind field reconstruction system of the laser radar under test, wherein the number of profiles of the radial wind speed in any direction is based on the needs of the three-dimensional wind field reconstruction system of the laser radar under test and the actual use of the laser radar;

[0065] S5. The signal containing the wind field is input into the coherent wind measuring laser radar under test through calculation by the calibrator, and the wind field signal is then inverted by the laser radar under test. The signals of the two wind fields are compared, thereby realizing the quantitative calibration of the coherent wind measuring laser radar under test.

[0066] In summary, the workflow of the present invention is:

[0067] When in use, parameters are input through the wind field, atmospheric scene and calibrated coherent wind laser radar parameter input module to set the wind field and atmospheric scene; for the wind field, ordinary users can select several preset typical wind fields, including strong wind and weak wind; expert users can edit custom wind fields and different profiles; for the atmospheric scene, ordinary users select preset atmospheric scenes, including heavy pollution, medium pollution and light pollution; expert users can edit custom atmospheric scenes; after the wind field and atmospheric scene are set, the operating mode of the laser radar under test and the telescope angle are input for radial mapping of the wind field and atmospheric scene, and then the frequency and amplitude errors of the signal generated by the coherent wind laser radar calibration instrument are corrected through the radial frequency profile correction module and the radial amplitude profile correction module, and after the correction is completed, the analog signal is output and modulated by the coherent wind laser radar calibration instrument, and the modulated optical signal is coupled into the coherent wind laser radar under test, and the wind field data inverted by the measured radar is compared with the preset wind field data to calibrate the coherent wind laser radar under test.

[0068] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention also fall within the protection scope of the present invention.

Claims

1. A coherent wind laser radar calibration system, characterized in that: It includes a wind field, an atmospheric scene and a calibrated coherent wind radar parameter input module, a wind field mapping module, an atmospheric scene simulation module, a radial frequency profile correction module, a radial amplitude profile correction module and an atmospheric scene output module; Wind field, atmospheric scene and calibrated coherent wind radar parameter input module: that is, the interactive module, through which the wind field, atmospheric scene settings and the measured radar measurement mode and telescope angle are input; Wind field mapping module: used to convert three-dimensional wind field information into radial information corresponding to the laser radar measurement mode under test, and perform radial mapping of the wind field; Atmospheric scene simulation module: used to simulate different atmospheric scenes, including the spatial and temporal distribution of three-dimensional wind fields and aerosols; Radial frequency profile correction module: used to correct the frequency error of the signal generated by the coherent wind lidar calibration instrument; Radial amplitude profile correction module: used to correct the amplitude error of the signal generated by the coherent wind lidar calibration instrument; Atmospheric scene output module: used to output the simulated wind speed information and profile frequency information calculated in the wind field mapping module to the control circuit of the calibration system, and then the control circuit drives the acousto-optic frequency shifter to modulate the laser echo signal with wind field information and aerosol information through the frequency shifter.

2. A coherent wind laser radar calibration system according to claim 1, characterized in that: The wind field mapping method of the wind field mapping module is: The first step is to convert the wind field information into the profile radial wind speed information according to the wind speed and wind direction angle of the three-dimensional wind field, the working mode of the laser radar being measured and the telescope angle. The formula is as follows: Among them, V Los is the calculated radial wind speed of the radar telescope under test, V h is the set horizontal wind speed, θ is the set wind direction angle, φ is the horizontal angle of the radar telescope under test, and α is the angle between the radar telescope under test and the horizontal plane; The second step is to divide the profile radial wind speed information into multiple single range gate radial wind speed information by range gate segmentation. The third step is to modulate the radial wind speed of the single range gate by analog signal and convert it into the radial frequency / spectrum information of the single range gate: in d =2V Los / λ Among them, f d is the calculated Doppler shift, λ is the wavelength of light; The fourth step is to reconstruct the profile of the calculated single range gate frequency / spectrum information according to the range gate segmentation order and reconstruct it into a profile echo signal.

3. A coherent wind laser radar calibration system according to claim 1, characterized in that: The radial frequency profile correction module tests the amplitude response of the signal generated by the coherent wind laser radar calibration instrument, and after obtaining the frequency error curve generated by the test, the system performs a linear fitting of y=ax+b on it to correct the error frequency to the accurate frequency.

4. A coherent wind laser radar calibration system according to claim 1, characterized in that: The radial amplitude profile correction module tests the amplitude response of the signal generated by the coherent wind laser radar calibration instrument, and performs inverse function calculation on the obtained curve to correct the generated amplitude error.

5. A coherent wind laser radar calibration method, characterized in that: The method is implemented based on the coherent wind laser radar calibration system according to any one of claims 1 to 4, and specifically comprises the following steps: S1. Select the system preset wind field or the custom wind field scene; select the system preset aerosol scene or the custom aerosol scene; input the measurement mode of the radar under test and the telescope angle for subsequent wind field mapping; S2. Perform wind field mapping according to the parameters set in the steps through a wind field mapping module; S3, performing a linear fit of y=ax+b on the measured value and theoretical value of the frequency shifter shift frequency, and correcting the error frequency to the accurate frequency; S4. Based on the wind speed projection and laser radar equation, as well as the radial amplitude profile correction module and the frequency and amplitude corrected by the radial amplitude profile correction module, simulate the radial wind speed in any direction of the atmospheric wind field, and calibrate the three-dimensional wind field reconstruction system of the laser radar under test, wherein the number of profiles of the radial wind speed in any direction is based on the needs of the three-dimensional wind field reconstruction system of the laser radar under test and the actual use of the laser radar; S5. The signal containing the wind field is input into the coherent wind measuring laser radar under test through calculation by the calibrator, and the wind field signal is then inverted by the laser radar under test. The signals of the two wind fields are compared, thereby realizing the quantitative calibration of the coherent wind measuring laser radar under test.

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