Real-time correction method for zero point position of direct wind measurement radar and wind measurement lidar system

Abstract

A direct wind measurement radar zero point position real-time correction method and a wind measurement laser radar system, comprising obtaining coherent detection channel data, first direct detection channel data and second direct detection channel data; inverting the coherent detection channel data to obtain corresponding first direct detection ideal data and second direct detection ideal data; fitting the first direct detection ideal data and the first direct detection channel data to obtain a first preliminary correction value under each range gate, and fitting the second direct detection ideal data and the second direct detection channel data to obtain a second preliminary correction value under each range gate; correcting the first direct detection channel data using a first final correction value screened from the first preliminary correction value under each range gate, and / or correcting the second direct detection channel data using a second final correction value screened from the second preliminary correction value under each range gate. The measurement error of the direct wind measurement laser radar caused by zero point drift is corrected.

Description

Technical Field

[0001] The present invention relates to the technical field of laser radars, and in particular to a real-time correction method for the zero point position of a direct wind measurement radar and a wind measurement laser radar system. Background Art

[0002] In the field of wind laser radar, wind laser radar can be divided into two different types according to the working mode or frequency discrimination mode: coherent detection laser radar and direct detection laser radar. The two different types of wind laser radar have different characteristics. At the same time, the difference in working mode makes both of them have some different advantages and disadvantages. Coherent wind laser radar usually mixes the scattered signal received in the atmosphere with the local oscillator signal split from the radar light source to obtain the frequency difference between the scattered signal and the local oscillator signal, and the wind speed is inverted by the size of the difference. The frequency discrimination of direct detection laser radar usually does not directly measure the size of the frequency, but uses fringe technology or edge technology to discriminate the frequency. Common frequency discriminators in direct detection laser radar are Fizeau interferometer and dual-channel FP (Fabry-Perot) standard. Among them, Fizeau interferometer uses interference to measure the optical path difference. Two optical plates have a small angle, forming a tiny wedge-shaped space part. After the echo signal is reflected multiple times inside this tiny space, an interference fringe will be formed along the wedge angle direction. The interference fringes formed by echo signals of different wavelengths have different positions. The dual-channel FP etalon contains two different receiving channels, each channel only allows photons within a narrow frequency band to pass through. The center wavelengths of the two receiving channels that can pass through the narrow frequency band have a slight difference. Assuming that the number of photons entering each channel is equal, or known, when the echo signals with different center wavelengths enter the two channels of the dual-channel FP etalon, there will be different transmittances. When the echo signal corresponding to the same wavelength enters two different dual-channel FP etalon channels, due to the different passband center wavelengths of the two channels, there will be different transmittances in the two channels, and then the signal strength detected in the two channels will be different. This difference can be used to invert the wavelength of the echo signal, and then obtain wind speed information.

[0003] However, in direct wind laser radar, the random drift of the frequency of the discriminator, the random drift of the frequency of the laser emission light, as well as weather problems or other system factors may cause the measurement accuracy of the direct wind laser radar to decrease. For the zero point random drift problem of direct wind laser radar, the discriminator is usually calibrated at the factory to minimize the impact of random drift. In the later use process, the drift problem that reappears over time is solved by regular calibration. Generally speaking, this process is a manual calibration process. In fact, for some equipment that needs to run automatically for a long time, regular manual intervention is required, which increases the difficulty of later maintenance. Summary of the invention

[0004] The main technical problem solved by the present invention is to combine the advantages of coherent wind measurement laser radar and direct wind measurement laser radar, improve the practicality and application range of laser radar, and improve the measurement error caused by zero drift of direct wind measurement laser radar.

[0005] According to the first aspect, an embodiment provides a direct wind measurement radar zero point position real-time correction method, which is applied to a dual-channel wind measurement laser radar system, wherein the dual-channel wind measurement laser radar system includes a coherent wind measurement laser radar and a direct wind measurement laser radar, the direct wind measurement laser radar includes a first direct detection channel and a second direct detection channel, and a plurality of mutually corresponding range gates at heights are respectively set in the coherent wind measurement laser radar and the direct wind measurement laser radar; the direct wind measurement radar zero point position real-time correction method is used to correct the measurement error caused by zero point drift of the direct wind measurement laser radar, and the direct wind measurement radar zero point position real-time correction method includes:

[0006] Acquire detection data collected by the dual-channel wind measurement laser radar system within a target time period, the detection data including coherent detection channel data collected by the coherent wind measurement laser radar, first direct detection channel data collected by the first direct detection channel of the direct wind measurement laser radar, and second direct detection channel data collected by the second direct detection channel of the direct wind measurement laser radar;

[0007] Performing wind speed inversion on the coherent detection channel data to obtain coherent channel wind speed data, and obtaining first direct detection ideal data and second direct detection ideal data based on the inversion of the coherent channel wind speed data;

[0008] Fitting the first direct detection ideal data and the first direct detection channel data to obtain a first preliminary correction value under each of the range gates, and fitting the second direct detection ideal data and the second direct detection channel data to obtain a second preliminary correction value under each of the range gates;

[0009] For the first direct detection channel, a first reference deviation value corresponding to different time points in each of the range gates within the target time period is calculated, and a first variance of the first reference deviation value corresponding to different time points is calculated; for the second direct detection channel, a second reference deviation value corresponding to different time points in each of the range gates within the target time period is calculated, and a second variance of the second reference deviation value corresponding to different time points is calculated;

[0010] Preliminarily screening the first preliminary correction value and the second preliminary correction value under each of the range gates based on the first variance and the second variance, and re-screening the first preliminary correction value and the second preliminary correction value under each of the range gates after the preliminary screening to obtain a first final correction value and a second final correction value that meet a preset re-screening requirement;

[0011] The first direct detection channel data is corrected using the first final correction value, and / or the second direct detection channel data is corrected using the second final correction value.

[0012] In some embodiments, the target time period includes n A divided time period, n is an integer not less than 2, and is set in the coherent wind laser radar and the direct wind laser radar respectively. J A distance gate, J is an integer not less than 2, and the first direct detection channel data includes E 1ij , the first direct detection ideal data includes , the first preliminary correction value under each of the range gates includes ,... ... ,in, i=1,...,n,j=1,...,J ;

[0013] The first preliminary correction value under each range gate is calculated by the following formula, which includes:

[0014] ,

[0015] in, represents the first preliminary correction value at the jth range gate within the target time period, n Indicates the number of divided time periods within the target time period, Indicated in i The first direct detection channel data at the jth range gate in a time period, Indicated in i The first direct detection ideal data at the jth range gate within a time period.

[0016] In some embodiments, the target time period includes n A divided time period, n is an integer not less than 2, and is set in the coherent wind laser radar and the direct wind laser radar respectively. J A distance gate, J is an integer not less than 2, and the second direct detection channel data includes E 2ij , the second direct detection ideal data includes , the second preliminary correction value under each of the range gates includes ,... ... ,in, i=1,...,n,j=1,...,J ;

[0017] The second preliminary correction value under each range gate is calculated by the following formula, which includes:

[0018] ,

[0019] in, represents the second preliminary correction value at the j-th range gate within the target time period, n Indicates the number of divided time periods within the target time period, Indicated in i The second direct detection channel data at the jth range gate in a time period, Indicated in i The second direct detection ideal data at the jth range gate within a time period.

[0020] In some embodiments, the step of obtaining the first direct detection ideal data and the second direct detection ideal data by inverting the coherent channel wind speed data includes:

[0021] Eliminate outliers and data that do not meet preset continuity conditions in the coherent channel wind speed data to obtain standard coherent channel wind speed data;

[0022] The standard coherent channel wind speed data is processed in sections according to preset time intervals to obtain the standard coherent channel wind speed data in multiple different time periods;

[0023] Performing wind speed averaging processing on the standard coherent channel wind speed data in each time period to obtain the average wind speed in different time periods, and forming coherent channel data points according to the average wind speed in different time periods;

[0024] The first direct detection ideal data and the second direct detection ideal data are obtained by inverting the coherent channel data points.

[0025] In some embodiments, the preliminarily screening the first preliminary correction value and the second preliminary correction value under each of the range gates based on the first variance and the second variance includes:

[0026] The first preliminary correction value and the second preliminary correction value under the range gate for which the first variance is not greater than the preset first variance threshold and the second variance is not greater than the preset first variance threshold are used as the first preliminary correction value and the second preliminary correction value under each of the range gates after preliminary screening.

[0027] In some embodiments, the first preliminary correction value and the second preliminary correction value under each of the range gates after preliminary screening are screened again to obtain the first final correction value and the second final correction value that meet the preset re-screening requirements, including:

[0028] Eliminate outliers and correction values ​​that do not meet preset continuity conditions in the first preliminary correction values ​​and the second preliminary correction values ​​under each of the range gates after the preliminary screening to obtain the remaining first preliminary correction values ​​and the second preliminary correction values ​​under the range gate;

[0029] A corresponding first residual variance is calculated according to the remaining first preliminary correction value under the range gate, and a corresponding second residual variance is calculated according to the remaining second preliminary correction value under the range gate;

[0030] When the first residual variance is not greater than a preset second variance threshold, and the second residual variance is not greater than a preset second variance threshold, calculating a first mean correction value corresponding to the remaining first preliminary correction value under the range gate, and calculating a second mean correction value corresponding to the remaining second preliminary correction value under the range gate;

[0031] The first mean correction value is used as a first final correction value, and the second mean correction value is used as a second final correction value.

[0032] In some embodiments, the target time period includes n A divided time period, n is an integer not less than 2, and is set in the coherent wind laser radar and the direct wind laser radar respectively. J A distance gate, J is an integer not less than 2, and the first direct detection channel data includes E 1ij , the second direct detection channel data includes E 2ij , the first direct detection ideal data includes , the second direct detection ideal data includes , the first preliminary correction value under each of the range gates includes ,... ... , the second preliminary correction value under each of the range gates includes ,... ... ,in, i=1,...,n,j=1,...,J ;

[0033] The first reference deviation value is calculated by the following formula:

[0034] ,

[0035] in, Indicated in i The first reference deviation value at the jth range gate in a time period, Indicated in i The first direct detection channel data at the jth range gate in a time period, Indicated in i The first direct detection ideal data at the jth range gate in a time period, represents the first preliminary correction value at the jth range gate within the target time period;

[0036] The second reference deviation value is calculated by the following formula:

[0037] ,

[0038] in, Indicated in i The second reference deviation value at the jth range gate in the time period, Indicated in i The second direct detection channel data at the jth range gate in a time period, Indicated in i The second direct detection ideal data at the jth range gate in the time period is: represents the second preliminary correction value at the j-th range gate within the target time period.

[0039] According to the second aspect, an embodiment provides a wind measurement laser radar system, comprising:

[0040] Coherent wind measurement laser radar, direct wind measurement laser radar and real-time correction module; wherein the coherent wind measurement laser radar includes a coherent detection light source emission module and a coherent wind measurement receiving channel, and the direct wind measurement laser radar includes a direct detection light source emission module, a first direct detection channel and a second direct detection channel;

[0041] The coherent detection light source transmitting module is used to transmit the laser pulses in the coherent wind measurement laser radar into the atmosphere, so that the laser pulses in the coherent wind measurement laser radar react with the atmosphere to generate coherent detection back echo signals;

[0042] The direct detection light source emission module is used to emit the laser pulse in the direct wind measurement laser radar into the atmosphere, so that the laser pulse in the direct wind measurement laser radar interacts with the atmosphere to generate a direct detection back echo signal;

[0043] The coherent wind measurement receiving channel is used to receive the coherent detection back echo signal, and acquire the coherent detection channel data from the coherent detection back echo signal;

[0044] The first direct detection channel is used to receive the direct detection backward echo signal and obtain first direct detection channel data by sampling the direct detection backward echo signal;

[0045] The second direct detection channel is used to receive the direct detection backward echo signal and obtain second direct detection channel data by sampling the direct detection backward echo signal;

[0046] The real-time correction module is used to generate the corresponding first final correction value and second final correction value using the real-time correction method of the direct wind measurement radar zero point position, and to perform real-time correction on the first direct detection channel data according to the first final correction value, and / or to perform real-time correction on the second direct detection channel data using the second final correction value.

[0047] In some embodiments, the measurement range between the coherent wind measurement lidar and the direct wind measurement lidar meets a preset overlapping range requirement.

[0048] In some embodiments, the coherent wind measurement receiving channel includes a balanced detector, which is used to convert the coupled optical signal obtained by mixing and superimposing the received coherent detection back echo signal and the local oscillator optical signal into coherent detection channel data; the first direct detection channel includes a photomultiplier tube, which is used to sample the direct detection back echo signal to obtain first direct detection channel data; and the second direct detection channel includes a photomultiplier tube, which is used to sample the direct detection back echo signal to obtain second direct detection channel data.

[0049] According to the direct wind radar zero point position real-time correction method and wind laser radar system of the above-mentioned embodiment, since the coherent detection channel data is collected according to the coherent wind laser radar, the first direct detection channel data is collected through the first direct detection channel of the direct wind laser radar, and the second direct detection channel data is collected through the second direct detection channel of the direct wind laser radar, so that the wind speed of the coherent detection channel data is inverted to obtain the coherent channel wind speed data, and the first direct detection ideal data and the second direct detection ideal data are inverted according to the coherent channel wind speed data. The first direct detection ideal data and the first direct detection channel data are fitted respectively to obtain the first preliminary correction value under each range gate, the second direct detection ideal data and the second direct detection channel data are fitted to obtain the second preliminary correction value under each range gate, and the first preliminary correction value and the second preliminary correction value are preliminarily screened and re-screened to obtain the first final correction value and the second final correction value that meet the screening conditions. By using the coherent wind laser radar and the direct wind laser radar in combination, the influence of the changeable weather in the low-altitude atmosphere on the measurement results can be filtered out, the anti-interference ability and robustness of the dual-channel wind laser radar in bad weather can be improved, and accurate coherent detection channel data, first direct detection channel data and second direct detection channel data can be obtained. The first direct detection channel data is corrected using the first final correction value, and / or the second direct detection channel data is corrected using the second final correction value, so as to improve the measurement error caused by the zero drift of the direct wind laser radar and improve the measurement accuracy of the direct wind laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a flow chart of a method for real-time correction of the zero point position of a direct wind measurement radar according to an embodiment of the present application;

[0051] Figure 2 A flowchart of a method for real-time correction of the zero point position of a direct wind measurement radar according to an embodiment;

[0052] Figure 3 A flowchart of another embodiment of obtaining first direct detection ideal data and second direct detection ideal data according to inversion of coherent channel wind speed data;

[0053] Figure 4 A flowchart of an embodiment of re-screening the first preliminary correction value and the second preliminary correction value under each range gate after preliminary screening to obtain the first final correction value and the second final correction value that meet the preset re-screening requirements;

[0054] Figure 5 A schematic structural diagram of a wind measurement laser radar system according to an embodiment;

[0055] Figure 6 A schematic diagram of the structure of a wind measurement laser radar system according to another embodiment. DETAILED DESCRIPTION

[0056] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0057] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0058] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0059] Please refer to Figure 1 and Figure 2 In an embodiment of the present invention, a direct wind measurement radar zero point position real-time correction method is provided, which is applied to a dual-channel wind measurement laser radar system. The direct wind measurement radar zero point position real-time correction method is used to correct the measurement error caused by zero point drift of the direct wind measurement laser radar. The direct wind measurement radar zero point position real-time correction method includes steps S10 to S60, which are described in detail below.

[0060] Step S10: Acquire detection data collected by the dual-channel wind laser radar system within a target time period.

[0061] In some embodiments, the dual-channel wind laser radar system includes a coherent wind laser radar and a direct wind laser radar, wherein the direct wind laser radar includes a first direct detection channel and a second direct detection channel. The dual-channel wind laser radar system is used to collect data within a target time period to obtain collected detection data, wherein the detection data includes coherent detection channel data collected by the coherent wind laser radar, first direct detection channel data collected by the first direct detection channel of the direct wind laser radar, and second direct detection channel data collected by the second direct detection channel of the direct wind laser radar.

[0062] In some embodiments, a plurality of range gates corresponding to each other at heights are respectively set in the coherent wind laser radar and the direct wind laser radar, and each range gate represents a distance unit divided in the detection space by the coherent wind laser radar and the direct wind laser radar. In order to facilitate subsequent data comparison, the relevant settings of the plurality of range gates in the coherent wind laser radar and the plurality of range gates in the direct wind laser radar are the same, and the relevant settings may refer to the length of a single range gate, that is, the length of the range gate in the coherent wind laser radar is the same as the length of the range gate in the direct wind laser radar.

[0063] Step S20: performing wind speed inversion on the coherent detection channel data to obtain coherent channel wind speed data, and obtaining first direct detection ideal data and second direct detection ideal data based on the inversion of the coherent channel wind speed data.

[0064] In some embodiments, wind speed inversion is performed on coherent detection channel data to obtain coherent channel wind speed data, wherein the wind speed inversion infers the wind speed by measuring the Doppler frequency shift of the interaction between the coherent detection channel data and particles in the atmosphere.

[0065] Please refer to Figure 3 In some embodiments, step S20 obtains first direct detection ideal data and second direct detection ideal data based on inversion of coherent channel wind speed data, including steps S21 to S24, which are described in detail below.

[0066] Step S21: remove outliers and data that do not meet preset continuity conditions in the coherent channel wind speed data to obtain standard coherent channel wind speed data.

[0067] In some embodiments, the preset continuity condition is that the difference between a single data point in the coherent channel wind speed data and several data points before and after it is not greater than a preset threshold. Therefore, the data that does not meet the preset continuity condition is a single data point in the coherent channel wind speed data that has a large deviation from the before and after data points.

[0068] Step S22: Segment processing is performed on the standard coherent channel wind speed data according to preset time intervals to obtain standard coherent channel wind speed data in multiple different time periods.

[0069] Step S23: performing wind speed averaging processing on the standard coherent channel wind speed data in each time period to obtain the average wind speed in different time periods, and forming coherent channel data points according to the average wind speed in different time periods.

[0070] In some embodiments, the time resolution of the dual-channel wind laser radar system can reach the second level, but in order to avoid the impact of rapid changes in wind speed under certain weather conditions, wind speed averaging processing is performed.

[0071] Step S24: obtaining first direct detection ideal data and second direct detection ideal data by inverting the coherent channel data points.

[0072] Step S30: Fit the first direct detection ideal data and the first direct detection channel data to obtain a first preliminary correction value under each range gate, and fit the second direct detection ideal data and the second direct detection channel data to obtain a second preliminary correction value under each range gate.

[0073] In some embodiments, before fitting the first direct detection ideal data and the first direct detection channel data, outliers and data that do not meet the preset continuity condition in the first direct detection channel data can be eliminated, and the first direct detection channel data after the outliers and the data that do not meet the preset continuity condition are segmented, and the first direct detection channel data after the segmentation time is averaged to obtain the average data of the first direct detection channel in different time periods, and the first direct detection channel data points are formed according to the average data of the first direct detection channel in different time periods, and the first direct detection channel data points are fitted with the first direct detection ideal data to obtain the first preliminary correction value under each range gate. The preset continuity condition in the first direct detection channel data is that the difference between a single data point and several data points before and after in the first direct detection channel data is not greater than a preset threshold. In addition, before fitting the second direct detection ideal data and the second direct detection channel data, the second direct detection channel data can also be processed, wherein the data processing process is similar to the data processing process of the first direct detection channel data, and will not be repeated here.

[0074] In some embodiments, the target time period includes n A divided time period, n is an integer not less than 2, and is set in the coherent wind laser radar and the direct wind laser radar respectively. J A distance gate, Jis an integer not less than 2, and the first direct detection channel data includes E 1ij , the first direct detection ideal data includes , the first preliminary correction value for each range gate includes ,... ... , the second direct detection channel data includes E 2ij , the second direct detection ideal data includes , the second preliminary correction value for each range gate includes ,... ... ,in, i=1,..., n,j=1,...,J.

[0075] In some embodiments, the first preliminary correction value under each range gate is calculated by the following formula, which includes:

[0076] ,

[0077] in, represents the first preliminary correction value at the jth range gate in the target time period, n Indicates the number of divided time periods within the target time period. Indicated in i The first direct detection channel data at the jth range gate in a time period, Indicated in i The first direct detection ideal data at the jth range gate in a time period.

[0078] In some embodiments, the second preliminary correction value under each range gate is calculated by the following formula, which includes:

[0079] ,

[0080] in, represents the second preliminary correction value at the jth range gate in the target time period, n Indicates the number of divided time periods within the target time period. Indicated in i The second direct detection channel data at the jth range gate in a time period, Indicated in i The second direct detection ideal data at the jth range gate in a time period.

[0081] Step S40: For the first direct detection channel, calculate the first reference deviation value corresponding to different time points in each range gate within the target time period, and calculate the first variance of the first reference deviation value corresponding to the different time points; for the second direct detection channel, calculate the second reference deviation value corresponding to different time points in each range gate within the target time period, and calculate the second variance of the second reference deviation value corresponding to the different time points.

[0082] In some embodiments, the first reference deviation value is calculated by the following formula:

[0083] ,

[0084] in, Indicated in i The first reference deviation value at the jth range gate in a time period, Indicated in i The first direct detection channel data at the jth range gate in a time period, Indicated in i The first direct detection ideal data at the jth range gate in a time period, It represents the first preliminary correction value at the jth range gate in the target time period.

[0085] In some embodiments, the second reference deviation value is calculated by the following formula:

[0086] ,

[0087] in, Indicated in i The second reference deviation value at the jth range gate in the time period, Indicated in i The second direct detection channel data at the jth range gate in a time period, Indicated in i The ideal data of the second direct detection at the jth range gate in the time period is: It represents the second preliminary correction value at the jth range gate in the target time period.

[0088] In some embodiments, for the first direct detection channel, the first reference deviation values ​​corresponding to different time points in each range gate within the target time period include ,..., , by calculating the first reference deviation value corresponding to different time points ,..., The variance of the first variance D 1jFor the second direct detection channel, the second reference deviation values ​​corresponding to different time points in the target time period in each range gate include ,..., , by calculating the second reference deviation value corresponding to different time points ,..., The variance of the second variance D 2j .

[0089] Step S50: Preliminarily screen the first preliminary correction value and the second preliminary correction value under each range gate based on the first variance and the second variance, and re-screen the first preliminary correction value and the second preliminary correction value under each range gate after the preliminary screening to obtain the first final correction value and the second final correction value that meet the preset re-screening requirements.

[0090] In some embodiments, the first preliminary correction value and the second preliminary correction value under each range gate are preliminarily screened based on the first variance and the second variance, including:

[0091] The first preliminary correction value and the second preliminary correction value under the range gate whose first variance is not greater than the preset first variance threshold and whose second variance is not greater than the preset first variance threshold are used as the first preliminary correction value and the second preliminary correction value under each range gate after preliminary screening.

[0092] In some embodiments, it is assumed that the first variance threshold is preset to be D max1 , when the first variance D 1j Not greater than the preset first variance threshold D max1 , and the second variance D 2j Not greater than the preset first variance threshold D max1 The first preliminary correction value and the second preliminary correction value under the range gate are used as the first preliminary correction value and the second preliminary correction value under each range gate after preliminary screening.

[0093] Please refer to Figure 4 In some embodiments, step S50 re-screens the first preliminary correction value and the second preliminary correction value under each distance gate after the preliminary screening to obtain the first final correction value and the second final correction value that meet the preset re-screening requirements, including steps S51 to S54, which are described in detail below.

[0094] Step S51: removing outliers and correction values ​​that do not meet preset continuity conditions from the first preliminary correction values ​​and the second preliminary correction values ​​under each range gate after preliminary screening to obtain the remaining first preliminary correction values ​​and the second preliminary correction values ​​under the range gate.

[0095] In some embodiments, the preset continuity condition in the first preliminary correction value and the second preliminary correction value is that the difference between a single data point and a plurality of preceding and succeeding data points in the first preliminary correction value and the second preliminary correction value is not greater than a preset threshold.

[0096] Step S52: Calculate the corresponding first residual variance according to the remaining first preliminary correction value under the range gate, and calculate the corresponding second residual variance according to the remaining second preliminary correction value under the range gate.

[0097] In some embodiments, the first residual variance is D1 and the second residual variance is D2.

[0098] Step S53: When the first residual variance is not greater than the preset second variance threshold, and the second residual variance is not greater than the preset second variance threshold, a first mean correction value corresponding to the first preliminary correction value under the remaining range gate is calculated, and a second mean correction value corresponding to the second preliminary correction value under the remaining range gate is calculated.

[0099] In some embodiments, it is assumed that the second variance threshold is preset to be D max2 , when the first residual variance D1 is not greater than the preset second variance threshold D max2 , and the second residual variance D2 is not greater than the preset second variance threshold D max2 When the first preliminary correction value under the remaining range gate is calculated, the first mean correction value corresponding to the first preliminary correction value under the remaining range gate is calculated, and the second mean correction value corresponding to the second preliminary correction value under the remaining range gate is calculated.

[0100] Step S54: using the first mean correction value as the first final correction value, and using the second mean correction value as the second final correction value.

[0101] In some embodiments, the first final correction value and the second final correction value are determined through preliminary screening and re-screening, so as to suppress the influence of accidental factors such as weather.

[0102] In some embodiments, the first preliminary correction values ​​under the remaining range gates can be weighted averaged to obtain a first weighted mean correction value, the second preliminary correction values ​​under the remaining range gates can be weighted averaged to obtain a second weighted mean correction value, and the first weighted mean correction value is used as the first final correction value, and the second weighted mean correction value is used as the second final correction value. The weights in the weighted average process can be adjusted accordingly according to the deployment location and season of the dual-channel wind laser radar system to improve the ability of the dual-channel wind laser radar system to adapt to the atmospheric conditions and weather and climate characteristics of the deployment location.

[0103] Step S60: Correct the first direct detection channel data using the first final correction value, and / or correct the second direct detection channel data using the second final correction value.

[0104] In some embodiments, during the real-time correction process, the first direct detection channel data can be corrected using the first final correction value, the second direct detection channel data can be corrected using the second final correction value, or the first direct detection channel data can be corrected using the second final correction value while the first direct detection channel data is being corrected using the first final correction value.

[0105] In some embodiments, detection data collected by a dual-channel wind laser radar system within a target time period is obtained, wherein the detection data includes coherent detection channel data collected by a coherent wind laser radar, first direct detection channel data collected by a first direct detection channel of a direct wind laser radar, and second direct detection channel data collected by a second direct detection channel of a direct wind laser radar. When the amount of coherent detection channel data collected by the coherent wind laser radar within the target time period is greater than a preset cumulative threshold, a difference calculation is performed between the coherent detection channel data under each range gate and the first direct detection channel data to obtain a first preliminary correction value under each range gate, and a difference calculation is performed between the coherent detection channel data under each range gate and the second direct detection channel data to obtain a second preliminary correction value under each range gate. The first direct detection channel data is corrected using the first final correction value, and / or the second direct detection channel data is corrected using the second final correction value.

[0106] In some embodiments, the coherent wind laser radar generally has higher accuracy, and the wind speed inverted by directly measuring the echo frequency is more accurate, but it relies more on the signal scattered by the aerosol in the boundary layer, and has limited measurement capabilities for high-altitude areas with sparse aerosol particles. As for the direct detection laser radar, by using the direct wind laser radar with the FP standard, the Rayleigh scattering signal of small molecules can be better utilized, or the cost of obtaining a high-power light source is lower. At a long distance, the influence of the weak signal on the coherence due to the long distance can be avoided to a certain extent, so the measurement distance is farther. The direct wind laser radar has a long working distance but usually has a random drift problem, while the coherent wind laser radar has a short working distance, but at the same time has good stability, high measurement accuracy and stronger anti-interference ability. Among them, the first direct detection channel and the second direct detection channel in the direct wind laser radar are used to detect the wind speed data of each altitude layer, and the coherent wind laser radar can provide a data basis for the data in the first direct detection channel and the second direct detection channel when performing data correction. At the same time, the wind speed data in the low altitude layer can also be directly provided by the coherent wind laser radar. By utilizing the high precision and good stability of the coherent wind laser radar, the measurement error caused by random drift in the direct wind laser radar is corrected in real time, the advantages of the coherent wind laser radar and the direct wind laser radar are combined, and at least one data screening is performed in the process of calculating the first final correction value and the second final correction value, that is, preliminary screening and re-screening, so as to reduce the random influence of occasional weather factors on the correction process. The first direct detection channel data is corrected by using the first final correction value, and / or the second direct detection channel data is corrected by using the second final correction value, so as to realize the correction of the data that cannot be covered by the coherent wind laser radar during the detection process of the direct wind laser radar.

[0107] In some embodiments, the signals output by the discriminator in the first direct detection channel and the second direct detection channel are used as the original data, and the wind speed data under each range gate of the coherent wind laser radar is used as the reference data. Compared with the wind laser radar system directly composed of the direct wind laser radar, the present application does not need to invert the wind speed from the original data, but calculates the ideal value through the reference data, and compares it with the original data to calculate the first final correction value and the second final correction value, and inverts the wind speed through the first final correction value and the second final correction value. Among them, the calculation of the first final correction value and the second final correction value assumes that the deviation of the measured values ​​of the first direct detection channel and the second direct detection channel within a period of time is a constant value. By assuming the concept of constancy, the corrected data is defined to complete the calculation. The calculation process of the deviation is linear, which can effectively reduce the amount of system calculation and increase the speed of data output.

[0108] Please refer to Figure 5In some embodiments, a wind measurement laser radar system is provided, including a coherent wind measurement laser radar 10, a direct wind measurement laser radar 20 and a real-time correction module 30, wherein the coherent wind measurement laser radar 10 includes a coherent detection light source transmitting module 101 and a coherent wind measurement receiving channel 102, and the direct wind measurement laser radar 20 includes a direct detection light source transmitting module 201, a first direct detection channel 202 and a second direct detection channel 203, which are described in detail below.

[0109] The coherent detection light source transmitting module 101 is used to transmit the laser pulses in the coherent wind measurement laser radar 10 into the atmosphere, so that the laser pulses in the coherent wind measurement laser radar 10 interact with the atmosphere to generate coherent detection back echo signals.

[0110] The direct detection light source transmitting module 201 is used to transmit the laser pulses in the direct wind measurement laser radar 20 into the atmosphere, so that the laser pulses in the direct wind measurement laser radar 20 interact with the atmosphere to generate direct detection back echo signals.

[0111] The coherent wind measurement receiving channel 102 is used to receive the coherent detection back echo signal and acquire the coherent detection channel data from the coherent detection back echo signal.

[0112] In some embodiments, in the coherent wind measurement receiving channel 102 , the coherent detection back echo signal may be received by a data receiving device composed of a large-aperture Cassegrain telescope and an ordinary telescope.

[0113] The first direct detection channel 202 is used to receive the direct detection backward echo signal and obtain first direct detection channel data by sampling the direct detection backward echo signal.

[0114] The second direct detection channel 203 is used to receive the direct detection backward echo signal and obtain second direct detection channel data by sampling the direct detection backward echo signal.

[0115] In some embodiments, in the first direct detection channel 202 and the second direct detection channel 203, a direct detection back echo signal can also be received by a receiving device composed of a large-aperture Cassegrain telescope and an ordinary telescope, and the first direct detection channel data and the second direct detection channel data can be obtained by sampling the direct detection back echo signal.

[0116] The real-time correction module 30 is used to generate the corresponding first final correction value and second final correction value using the real-time correction method of the direct wind measurement radar zero point position, and to perform real-time correction on the first direct detection channel data according to the first final correction value, and / or to perform real-time correction on the second direct detection channel data using the second final correction value.

[0117] In some embodiments, the real-time correction module 30 is responsible for implementing the real-time correction. Generally speaking, the real-time correction module 30 includes an industrial computer and a signal timing pulse generating device.

[0118] In some embodiments, in order to achieve the purpose of providing a reference benchmark for the measurement of the coherent wind laser radar 10 to the direct wind laser radar 20, the measurement range between the coherent wind laser radar 10 and the direct wind laser radar 20 should meet the preset overlap range requirement. Generally speaking, considering that the vertical detection range of the coherent wind laser radar does not exceed 4km, and the long-range direct wind laser radar may have blind spots and saturation at close range, the overlap range requirement is generally 2km-4km for the coherent wind laser radar and the direct wind laser radar.

[0119] In some embodiments, a balanced detector is included in the coherent wind measurement receiving channel 102, and a photomultiplier tube is included in the first direct detection channel 202 and the second direct detection channel 203. The balanced detector converts the coupled optical signal after mixing and superimposing the received coherent detection back echo signal and the local oscillator optical signal into coherent detection channel data, and the photomultiplier tube is used to sample the direct detection back echo signal to obtain the first direct detection channel data and the second direct detection channel data. Wherein, after passing through the coupler, the coherent detection back echo signal is mixed and superimposed with the local oscillator optical signal to obtain two coupled optical signals with opposite output phases, and the two coupled optical signals with opposite output phases are input to the input end of the balanced detector, and after photoelectric conversion and DC component filtering inside the balanced detector, an AC RF radio frequency output signal is obtained, that is, the coherent detection channel data. The photomultiplier tube is used to sample the signal of the direct wind measurement radar. According to the actual design of the instrument, the system without coherent wind measurement lidar will include two or four photomultiplier tubes. When there are more than two photomultiplier tubes, it is usually because the system is divided into two channels, high altitude and low altitude. When the high altitude channel observes the measurement data at ultra-low altitude close to the ground, it will be saturated because the gain of the photomultiplier tube is set too high, affecting the normal observation at low altitude. Therefore, there will be a group of high-gain setting photomultiplier tubes for high altitude and a group of lower setting gain photomultiplier tubes for medium and low altitude. In the system including coherent wind measurement lidar, only two photomultiplier tubes are needed without special requirements. The low-altitude wind speed measurement data can be completed by the coherent wind measurement channel, which is also the advantage of using the system of this application.

[0120] In some embodiments, a method for real-time correction of the zero point position of a direct wind measurement radar includes: acquiring detection data collected by a dual-channel wind measurement laser radar system within a target time period, the detection data including coherent detection channel data collected by the coherent wind measurement laser radar, first direct detection channel data collected by the first direct detection channel of the direct wind measurement laser radar, and second direct detection channel data collected by the second direct detection channel of the direct wind measurement laser radar; performing wind speed inversion on the coherent detection channel data to obtain coherent channel wind speed data, and obtaining first direct detection ideal data and second direct detection ideal data based on the inversion of the coherent channel wind speed data; fitting the first direct detection ideal data and the first direct detection channel data to obtain a first preliminary correction value under each range gate, and fitting the second direct detection ideal data and the second direct detection channel data to obtain a second preliminary correction value under each range gate. positive value; for the first direct detection channel, calculating the first reference deviation value corresponding to different time points in each range gate within the target time period, and calculating the first variance of the first reference deviation value corresponding to the different time points; for the second direct detection channel, calculating the second reference deviation value corresponding to different time points in each range gate within the target time period, and calculating the second variance of the second reference deviation value corresponding to the different time points; preliminarily screening the first preliminary correction value and the second preliminary correction value under each range gate based on the first variance and the second variance, and re-screening the first preliminary correction value and the second preliminary correction value under each range gate after the preliminary screening to obtain the first final correction value and the second final correction value that meet the preset re-screening requirements; correcting the first direct detection channel data using the first final correction value, and / or correcting the second direct detection channel data using the second final correction value.

[0121] Please refer to Figure 6 In some embodiments, in a wind laser radar system, a coherent wind channel secondary mirror in a coherent wind laser radar can receive laser pulses sent by a coherent channel laser and emit them into the atmosphere, and generate a coherent detection back echo signal generated after interacting with the atmosphere, and a balanced detector converts the received coherent detection back echo signal and a local oscillator optical signal into a sampled coherent detection channel data after mixing and superimposing the coupled optical signal. A direct wind channel primary mirror in a direct wind laser radar can receive laser pulses sent by a direct channel laser. A dual-channel signal acquisition module can receive a coherent detection back echo signal and a direct detection back echo signal, sample the coherent detection back echo signal to obtain coherent detection channel data, sample the direct detection back echo signal to obtain first direct detection channel data and second direct detection channel data, and send the first direct detection channel data and the second direct detection channel data to a radar control module to achieve real-time correction of the first direct detection channel data and the second direct detection channel data.

[0122] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0123] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A real-time correction method for the zero position of a direct wind radar, applied to a dual-channel wind laser radar system, wherein: The dual-channel wind measurement laser radar system includes a coherent wind measurement laser radar and a direct wind measurement laser radar, the direct wind measurement laser radar includes a first direct detection channel and a second direct detection channel, and a plurality of mutually corresponding range gates at different heights are respectively set in the coherent wind measurement laser radar and the direct wind measurement laser radar; the method is characterized in that the direct wind measurement radar zero point position real-time correction method is used to correct the measurement error caused by the zero point drift of the direct wind measurement laser radar, and the direct wind measurement radar zero point position real-time correction method includes: Acquire detection data collected by the dual-channel wind measurement laser radar system within a target time period, the detection data including coherent detection channel data collected by the coherent wind measurement laser radar, first direct detection channel data collected by the first direct detection channel of the direct wind measurement laser radar, and second direct detection channel data collected by the second direct detection channel of the direct wind measurement laser radar; Performing wind speed inversion on the coherent detection channel data to obtain coherent channel wind speed data, and obtaining first direct detection ideal data and second direct detection ideal data based on the inversion of the coherent channel wind speed data; Fitting the first direct detection ideal data and the first direct detection channel data to obtain a first preliminary correction value under each of the range gates, and fitting the second direct detection ideal data and the second direct detection channel data to obtain a second preliminary correction value under each of the range gates; The target time period includes n A divided time period, n is an integer not less than 2, and is set in the coherent wind laser radar and the direct wind laser radar respectively. J A distance gate, J is an integer not less than 2, and the first direct detection channel data includes E 1ij , the first direct detection ideal data includes , the first preliminary correction value under each of the range gates includes ,..., ,..., , the second direct detection channel data includes E 2ij , the second direct detection ideal data includes , the second preliminary correction value under each of the range gates includes ,..., ,..., ,in, i=1,...,n,j=1,...,J ; The first preliminary correction value under each range gate is calculated by the following formula, which includes: ， in, represents the first preliminary correction value at the jth range gate within the target time period, n Indicates the number of divided time periods within the target time period, E 1ij Indicated in i The first direct detection channel data at the jth range gate in a time period, Indicated in i The first direct detection ideal data at the jth range gate in a time period; The second preliminary correction value under each range gate is calculated by the following formula, which includes: ， in, represents the second preliminary correction value at the j-th range gate within the target time period, n Indicates the number of divided time periods within the target time period, E 2ij Indicated in i The second direct detection channel data at the jth range gate in a time period, Indicated in i The second direct detection ideal data at the jth range gate in a time period; For the first direct detection channel, a first reference deviation value corresponding to different time points in each of the range gates within the target time period is calculated, and a first variance of the first reference deviation value corresponding to different time points is calculated; for the second direct detection channel, a second reference deviation value corresponding to different time points in each of the range gates within the target time period is calculated, and a second variance of the second reference deviation value corresponding to different time points is calculated; Preliminarily screening the first preliminary correction value and the second preliminary correction value under each of the range gates based on the first variance and the second variance, and re-screening the first preliminary correction value and the second preliminary correction value under each of the range gates after the preliminary screening to obtain a first final correction value and a second final correction value that meet a preset re-screening requirement; The first direct detection channel data is corrected using the first final correction value, and / or the second direct detection channel data is corrected using the second final correction value.

2. The direct wind radar zero position real-time correction method according to claim 1, characterized in that: The step of obtaining the first direct detection ideal data and the second direct detection ideal data by inverting the coherent channel wind speed data comprises: Eliminate outliers and data that do not meet preset continuity conditions in the coherent channel wind speed data to obtain standard coherent channel wind speed data; The standard coherent channel wind speed data is processed in sections according to preset time intervals to obtain the standard coherent channel wind speed data in multiple different time periods; Performing wind speed averaging processing on the standard coherent channel wind speed data in each time period to obtain the average wind speed in different time periods, and forming coherent channel data points according to the average wind speed in different time periods; The first direct detection ideal data and the second direct detection ideal data are obtained by inverting the coherent channel data points.

3. The real-time correction method for zero position of direct wind radar according to claim 1, characterized in that: The preliminarily screening the first preliminary correction value and the second preliminary correction value under each of the range gates based on the first variance and the second variance includes: The first preliminary correction value and the second preliminary correction value under the range gate for which the first variance is not greater than the preset first variance threshold and the second variance is not greater than the preset first variance threshold are used as the first preliminary correction value and the second preliminary correction value under each of the range gates after preliminary screening.

4. The direct wind radar zero position real-time correction method according to claim 1, characterized in that: The first preliminary correction value and the second preliminary correction value under each of the range gates after the preliminary screening are screened again to obtain the first final correction value and the second final correction value that meet the preset re-screening requirements, including: Eliminate outliers and correction values ​​that do not meet preset continuity conditions in the first preliminary correction values ​​and the second preliminary correction values ​​under each of the range gates after the preliminary screening to obtain the remaining first preliminary correction values ​​and the second preliminary correction values ​​under the range gate; A corresponding first residual variance is calculated according to the remaining first preliminary correction value under the range gate, and a corresponding second residual variance is calculated according to the remaining second preliminary correction value under the range gate; When the first residual variance is not greater than a preset second variance threshold, and the second residual variance is not greater than a preset second variance threshold, calculating a first mean correction value corresponding to the remaining first preliminary correction value under the range gate, and calculating a second mean correction value corresponding to the remaining second preliminary correction value under the range gate; The first mean correction value is used as a first final correction value, and the second mean correction value is used as a second final correction value.

5. The real-time correction method for the zero position of a direct wind measurement radar as claimed in claim 1, characterized in that: The first reference deviation value is calculated by the following formula: ， in, Indicated in i The first reference deviation value at the jth range gate in a time period, Indicated in i The first direct detection channel data at the jth range gate in a time period, Indicated in i The first direct detection ideal data at the jth range gate in a time period, represents the first preliminary correction value at the jth range gate within the target time period; The second reference deviation value is calculated by the following formula: ， in, Indicated in i The second reference deviation value at the jth range gate in the time period, Indicated in i The second direct detection channel data at the jth range gate in a time period, Indicated in i The second direct detection ideal data at the jth range gate in the time period is: represents the second preliminary correction value at the j-th range gate within the target time period.

6. A wind laser radar system, characterized in that: include: Coherent wind measurement laser radar, direct wind measurement laser radar and real-time correction module; wherein the coherent wind measurement laser radar includes a coherent detection light source emission module and a coherent wind measurement receiving channel, and the direct wind measurement laser radar includes a direct detection light source emission module, a first direct detection channel and a second direct detection channel; The coherent detection light source transmitting module is used to transmit the laser pulses in the coherent wind measurement laser radar into the atmosphere, so that the laser pulses in the coherent wind measurement laser radar react with the atmosphere to generate coherent detection back echo signals; The direct detection light source emission module is used to emit the laser pulse in the direct wind measurement laser radar into the atmosphere, so that the laser pulse in the direct wind measurement laser radar interacts with the atmosphere to generate a direct detection back echo signal; The coherent wind measurement receiving channel is used to receive the coherent detection back echo signal, and acquire the coherent detection channel data from the coherent detection back echo signal; The first direct detection channel is used to receive the direct detection backward echo signal and obtain first direct detection channel data by sampling the direct detection backward echo signal; The second direct detection channel is used to receive the direct detection backward echo signal and obtain second direct detection channel data by sampling the direct detection backward echo signal; The real-time correction module is used to generate the corresponding first final correction value and second final correction value using the real-time correction method for the zero point position of the direct wind measurement radar as described in any one of claims 1-5, and to perform real-time correction on the first direct detection channel data according to the first final correction value, and / or to perform real-time correction on the second direct detection channel data using the second final correction value.

7. The wind laser radar system according to claim 6, characterized in that: The measurement range between the coherent wind measurement laser radar and the direct wind measurement laser radar meets the preset overlapping range requirement.

8. The wind laser radar system according to claim 6, characterized in that: The coherent wind measurement receiving channel includes a balanced detector, which is used to convert the coupled optical signal obtained by mixing and superimposing the received coherent detection back echo signal and the local oscillator optical signal into coherent detection channel data. The first direct detection channel includes a photomultiplier tube, which is used to sample the direct detection back echo signal to obtain first direct detection channel data. The second direct detection channel includes a photomultiplier tube, which is used to sample the direct detection back echo signal to obtain second direct detection channel data.

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