Millimeter wave radar measurement method considering multiple influence factors

Abstract

The invention discloses a millimeter-wave radar measurement method considering various influence factors, and the method comprises the steps: carrying out the range finding refinement of a millimeter-wave radar, and carrying out the refinement of a range finding value in a precision interval based on a fast Fourier transform method and linear frequency modulation transformation; constructing a distance measurement error fine compensation model, and obtaining an accurate distance measurement value of the radar to the target; according to the distance, the azimuth angle and the pitch angle of the radar and the target after compensation, target coarse positioning is carried out, and a millimeter wave radar high-precision measurement model considering various influence factors is constructed by combining the single observation radar pulse measurement precision difference, the real distance and the signal-to-noise ratio comprehensive fixed weight. And high-precision measurement data of the millimeter wave radar considering various influence factors are obtained. The position of the corner reflector is obtained through spatial distance intersection. The problem of insufficient ranging precision of the millimeter wave radar is solved, the influence of radar electronic element delay, angle and meteorological factors is eliminated, and the rapid measurement of the geometric state of the track is realized by using a precise observation model.

Description

Technical Field

[0001] The present invention relates to the technical field of railway engineering measurement, and in particular to a millimeter wave radar measurement method for estimating multiple influencing factors. Background Art

[0002] Against the backdrop of the rapid development of high-speed rail in my country, the operational safety of high-speed rail faces problems such as deformation of structures such as roadbeds, bridges, and tracks, as well as potential geological disasters along the line. When trains are running at high speeds, slight deformation of roadbeds and bridges can lead to uneven tracks, causing trains to slow down and even affecting driving safety. Therefore, track geometry detection is crucial to the safe operation of high-speed rail.

[0003] To ensure safe train movement, railway authorities must regularly inspect the geometry of railway tracks and perform repairs and maintenance. Currently, Beidou positioning technology, due to its high precision and all-weather capabilities, has become one of the most mature track inspection solutions outside tunnels. During railway track inspection, the need for positioning and safety testing extends beyond tunnels; measurement and positioning are also required inside tunnels. Total stations, traditional high-precision measurement equipment, integrate inertial navigation and other technologies. By providing reference coordinates and using inertial navigation systems to compensate for dynamic errors, they have enabled static measurement of track geometry parameters (such as gauge, level, and height) inside tunnels. However, total stations remain imported, leading to high prices, low efficiency, and inadequate data security.

[0004] Millimeter-wave radar is a radar system that uses the millimeter-wave frequency band for detection and ranging. It can penetrate obstacles such as water vapor and smoke and is unaffected by lighting conditions. It can simultaneously identify multiple targets and offers advantages such as long time series, real-time performance, high precision (submillimeter level), and non-contact performance. Compared to measurement robots costing hundreds of thousands of yuan, millimeter-wave radar is relatively affordable (500 to 2000 yuan), offering a cost-effective solution. However, millimeter-wave radar is primarily used for deflection monitoring of structures such as bridges, and achieving high-precision positioning in the complex environments of tunnels has not been thoroughly studied. Therefore, a millimeter-wave radar measurement method that accounts for multiple influencing factors is urgently needed, eliminating the effects of radar electronic component delay, angle, and meteorological factors, and constructing a precise observation model to achieve rapid measurement of track geometry. Summary of the Invention

[0005] Therefore, the purpose of the present invention is to provide a millimeter wave radar measurement method that takes into account multiple influencing factors, and to solve the problems of low efficiency, high cost, and lack of data security in measuring track geometry in railway tunnels.

[0006] To achieve the above objectives, the present invention provides a millimeter wave radar measurement method that takes into account multiple influencing factors, comprising the following steps: S1. Obtaining raw radar data and performing fine processing on the obtained raw radar data to obtain the precise distance measurement value of a single radar to the target; S2. Set the azimuth and elevation angles of the radar transmitter to 0; and construct a ranging error compensation model. S3, alternately transforming the azimuth and elevation angles of the radar to the angle transmitter to construct a millimeter wave radar angle error model; S4. Compensate the distance obtained by the radar measuring the corner reflector using a range error model and an angle error model, measure the temperature and humidity near the radar using a temperature and humidity meter, analyze the relationship between the temperature, humidity, and the compensated distance, and construct a meteorological correction model; S5. Obtain the initial coordinates based on the original radar data of S1, and use the ranging error compensation model of S2, the millimeter-wave radar angle error model of S3, and the meteorological correction model of S4 to obtain the corrected precise distance observation value. According to the influence of single-pulse measurement error, distance length, and signal-to-noise ratio on the measurement, a high-precision measurement model of millimeter-wave radar that takes into account multiple influencing factors is constructed. The high-precision measurement model of millimeter-wave radar is used to obtain high-precision measurement data of millimeter-wave radar that takes into account multiple influencing factors.

[0007] Further preferably, in S1, the performing fine processing on the acquired raw radar data to obtain an accurate ranging value of a single radar to a target includes: S101, coarse extraction of distance values ​​includes taking the corner reflector as a target, calculating the frequency of discrete beat signals in the original radar data using FFT, selecting the frequency corresponding to the signal with the maximum amplitude, and converting it to obtain the target radial distance; S102, spectrum refinement, including coarse extraction of the target radial distance, determining the frequency corresponding to the target between the left and right adjacent spectrum lines of the maximum spectrum line, and using CZT to refine the spectrum line to obtain the unambiguous phase of the target; S103: Refine the distance measurement value by calculating the phase difference between the two distance measurements based on the unambiguous phase of the target and converting the phase difference into the corresponding distance change. ,Will By adding it to the first distance measurement value, the precise distance measurement value of the next epoch can be obtained.

[0008] Further preferably, in S2, the azimuth angle and the elevation angle of the radar reaching angle transmitter are set to 0; and a ranging error compensation model is constructed, including: The pitch angle and horizontal angle of the radar antenna and corner reflector were adjusted to 0°. The corner reflector was linearly translated 2000 times from 0.5m to 200m in steps of 0.1m. The true absolute distance between the radar and the corner reflector was obtained as the true value. The difference between the distance and the distance measured by the radar and the corner reflector was used to obtain the optimal linear function model with the true value, which was used as the ranging error compensation model.

[0009] Further preferably, in S3, alternately transforming the azimuth angle and the elevation angle of the radar angle transmitter to construct the millimeter wave radar angle error model includes: The pitch angle between the radar and the corner reflector was fixed at 0°, and the horizontal angle was rotated from -60° to 60° in 5° steps for 25 times. The measured value obtained by the ranging error compensation model was subtracted from the true value to construct an optimal function model between the error and the horizontal angle. The horizontal angle is fixed at 0°, and the pitch angle is rotated from -30° to 30° with a step size of 5° for a total of 13 times. The measured value obtained by the ranging error compensation model is subtracted from the true value to construct an optimal function model between the error and the pitch angle.

[0010] Further preferably, the step of measuring the temperature and humidity near the radar using a thermometer and hygrometer, analyzing the relationship between the temperature, humidity and the compensated distance, and constructing a meteorological correction model comprises the following steps: Select any distance within 200m from the radar, use a temperature and humidity meter and a timed photography program to measure the real-time meteorological factors on site, including temperature and humidity values; Correcting the radar ranging value in sequence using the ranging error compensation model and the millimeter-wave radar angle error model to obtain a compensated radar ranging distance; The temperature value, humidity value and radar ranging distance are used to construct a mapping relationship matrix between real-time weather and corrected ranging values ​​to form a weather correction model.

[0011] Further preferably, in S5, the constructing of a millimeter wave radar high-precision measurement model taking into account multiple influencing factors includes: S501, setting the approximate coordinates of any corner reflector, and expanding it according to Taylor series to obtain the millimeter wave distance observation value of the corner reflector; S502, using nonlinear least squares estimation to calculate correction values ​​of unknown parameters based on the observation equation when i radars simultaneously observe the same target at any time and the obtained millimeter wave range observation value; S503. Based on the difference in measurement accuracy of single-observation radar pulses, the true distance, and the signal-to-noise ratio, comprehensive weighting is performed to establish a high-precision measurement model for millimeter-wave radar that takes into account multiple influencing factors, and to calculate the approximate coordinates of the corner reflector.

[0012] Further preferably, in S501, the approximate coordinates of any corner reflector are set, and the millimeter wave distance observation value of the corner reflector is obtained according to Taylor series expansion, including: Assume the approximate coordinates of any corner reflector to be , the coordinates of the i-th radar are ,exist The first-order Taylor series expansion at is: in, represents the millimeter wave distance observation value; Indicates the true value of the geometric distance from the millimeter wave radar to the angle reflector; , , All are intermediate variables; , , ; 、 、 They are 、 、 The coordinate increment for the direction.

[0013] Further preferably, in S502, according to the observation equation when i radars simultaneously observe the same target at any time and the obtained millimeter wave range observation value, nonlinear least squares estimation is used to calculate the correction value of the unknown parameter, which includes: The observation equation is , make , The observation equation can be abbreviated as ; Use nonlinear least squares estimation to calculate the corrected values ​​of the unknown parameters: Where, is the initial value of the parameter to be estimated, that is, the approximate value of the target coordinate ; is the parameter correction number obtained; Estimate the parameters obtained each time; is the weight matrix.

[0014] Further preferably, in S503, when performing comprehensive weighting based on the single observation radar pulse measurement accuracy difference, the true distance, and the signal-to-noise ratio, the weighting formula is as follows: Where, The intermediate variable is calculated to integrate the difference in single observation radar pulse measurement accuracy, true distance and signal-to-noise ratio, i=1, 2, …, n, where n is the number of millimeter-wave radars. ; is the true distance of the i-th radar to the target j at the k-th epoch; is the pulse measurement accuracy difference of target j by the i-th radar at epoch k; is the signal-to-noise ratio of the i-th radar to the target j at epoch k.

[0015] The millimeter-wave radar measurement method disclosed in this application, which takes into account multiple influencing factors, can effectively solve the shortcomings of the existing technology. The present invention uses the FFT frequency method and CZT to refine the ranging value within the accuracy range. To address the problem of insufficient millimeter-wave radar ranging accuracy, the present invention analyzes the correlation between distance and radar electronic component delay, true distance, angle-related errors, and meteorological factors, constructs a ranging error refinement compensation model, and obtains the radar's accurate ranging value for the target; based on the distance, azimuth, and pitch angle compensated by the radar and the corner reflector, the target is roughly located. A precise random model is established by combining the measurement accuracy difference of the single-observation radar pulse, the true distance, and the signal-to-noise ratio. The spatial distance intersection method is used to measure the position of the corner reflector to achieve millimeter-level rapid measurement of the track geometry in the tunnel. The present invention solves the problem of relying on foreign total station equipment for measurement in railway tunnels, improves the efficiency and accuracy of millimeter-wave radar measurement in complex tunnel environments, and effectively saves measurement costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of the millimeter wave radar measurement method provided by the present invention that takes into account multiple influencing factors.

[0017] Figure 2 This is a flow chart of the millimeter wave radar ranging refinement method in the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1 As shown, an embodiment of one aspect of the present invention provides a millimeter wave radar measurement method that takes into account multiple influencing factors, including the following steps: S1. Obtaining raw radar data and performing fine processing on the obtained raw radar data to obtain an accurate range value of a single radar to a target; further preferably, as Figure 2 As shown, in S1, the refined processing of the acquired raw radar data to obtain the precise distance measurement value of a single radar to the target includes: S101, coarse extraction of distance values, including: using a corner reflector as a target, using FFT to calculate the frequency of discrete beat signals in the raw radar data (primarily peaks with strong amplitudes and concentrated frequencies), selecting the frequency corresponding to the signal with the maximum amplitude, and converting it to obtain the target radial distance; the corner reflector is an octagonal one. The calculation formula is as follows: Where, is the propagation speed of the signal in the atmosphere, is the sampling frequency, is the quantized frequency point after FFT, is the signal frequency modulation slope, is the complex sampling point.

[0020] The search interval is determined by the calculated target radial distance (prior distance), the signal with the maximum amplitude is selected, the point with the maximum amplitude in the search interval is determined, and the frequency fc corresponding to the maximum FFT amplitude is determined.

[0021] S102, spectrum refinement, including rough extraction of the target radial distance, determining the frequency corresponding to the target between the left and right adjacent spectral lines of the maximum spectral line (i.e., determining the spectrum refinement interval based on the FFT result, selecting the one with the largest amplitude), and using CZT to refine the spectral line to obtain the unambiguous phase of the target (i.e., the frequency and phase corresponding to the maximum CZT amplitude); the starting point of the refined frequency is the left spectral line adjacent to the maximum spectral line, and the end point is the right spectral line adjacent to the maximum spectral line. The local spectrum is refined from the original two points to To avoid phase ambiguity, the phase difference between adjacent spectral lines should not exceed , thus determining the refinement multiple .

[0022] S103, ranging value refinement, based on the target's unambiguous phase (i.e., the frequency and phase corresponding to the maximum CZT amplitude of the first epoch and the frequency and phase corresponding to the maximum CZT amplitude of the second epoch), calculate the phase difference between the two ranging measurements, calculate the radial deformation distance according to the formula; convert the phase difference into the corresponding distance change ,Will By adding it to the first distance measurement value, the precise distance measurement value of the next epoch can be obtained.

[0023] The distance value is refined by calculating the phase difference between two distance measurements and converting it into the corresponding distance change. ,Will By adding it to the first distance measurement value, the precise distance measurement value of the next epoch can be obtained.

[0024] During the first ranging, the phase of the beat signal obtained by the radar diagonal reflector is: The target deformation information is: Where, is the phase difference between the two ranging measurements, is the signal starting frequency, is the signal frequency modulation period, is the time delay from signal transmission to echo reception during the first ranging, is the initial phase; is the quantized frequency point after FFT; therefore, the ranging error compensation model is expressed as follows d t+1 =d t +△d .

[0025] S2. Set the azimuth and elevation angles of the radar transmitter to 0; and construct a ranging error compensation model. The azimuth and elevation angles of the radar transmitter are set to 0; a ranging error compensation model is constructed, including: The pitch angle and horizontal angle of the radar antenna and corner reflector were adjusted to 0°. The corner reflector was linearly translated 2000 times from 0.5m to 200m in steps of 0.1m. The true absolute distance between the radar and the corner reflector was obtained by Leica Tracker AT960 in conjunction with T-Pro as the true value. The difference between the distance and the corner reflector measured by the radar was used to obtain the optimal linear function model with the true value, which was used as the ranging error compensation model.

[0026] S3, alternately transforming the azimuth and elevation angles of the radar to the angle transmitter to construct a millimeter wave radar angle error model; Furthermore, in S3, the azimuth and elevation angles of the radar transmitter are alternately transformed to construct a millimeter-wave radar angle error model, including: The pitch angle between the radar and the corner reflector was fixed at 0°, and the horizontal angle was rotated from -60° to 60° in 5° steps for 25 times. The measured value obtained by the ranging error compensation model was subtracted from the true value to construct an optimal function model between the error and the horizontal angle. Based on the test data, this application uses a trigonometric function with a term of 1 to fit the deviation between the true value and the measured value of the horizontal angle collected multiple times. The result has the smallest RMSE and a high R-squared. Therefore, the optimal function model between the error and the horizontal angle is expressed by the following formula: x is the radar horizontal angle, and f(x) is the deviation between the radar ranging value and the true distance (after ranging error model compensation).

[0027] The horizontal angle is fixed at 0°, and the pitch angle is rotated from -30° to 30° with a step size of 5° for a total of 13 times. The measured value obtained by the ranging error compensation model is subtracted from the true value to construct an optimal function model between the error and the pitch angle.

[0028] Similarly, based on the test data, this application uses a first-order polynomial fitting result to minimize the RMSE of the deviation between the true value and the measured value corresponding to the pitch angle collected multiple times. Therefore, the optimal function model between the error and the pitch angle is expressed by the following formula: x is the radar pitch angle, and f(x) is the deviation between the radar ranging value and the true distance (after ranging error model compensation).

[0029] S4. Compensate the distance obtained by the radar measuring the corner reflector using a range error model and an angle error model, measure the temperature and humidity near the radar using a temperature and humidity meter, analyze the relationship between the temperature, humidity, and the compensated distance, and construct a meteorological correction model; Further preferably, the step of measuring the temperature and humidity near the radar using a thermometer and hygrometer, analyzing the relationship between the temperature, humidity and the compensated distance, and constructing a meteorological correction model comprises the following steps: Select any distance within 200m from the radar, use a temperature and humidity meter and a timed photography program to measure the real-time meteorological factors on site, including temperature and humidity values; Correcting the radar ranging value in sequence using the ranging error compensation model and the millimeter-wave radar angle error model to obtain a compensated radar ranging distance; The temperature value, humidity value and radar ranging distance are used to construct a mapping relationship matrix between real-time weather and corrected ranging values ​​to form a weather correction model.

[0030] According to the resolution of the 13th International Association of Geodesy, the formula for calculating the refractive index n of the modulated carrier (light wave) under actual meteorological conditions is: (4-1) Where, is the air expansion coefficient, and ; t is the actual atmospheric dry temperature, unit is ℃; P is the actual atmospheric pressure, unit is mmHg; e is the actual water vapor pressure, in mmHg. n g Standard meteorological conditions ( t =0℃, P =760mmHg, e =0mmHg), the refractive index of the modulated light is calculated as follows: (4-2) Where, λ is the wavelength of monochromatic light, in micrometers (μm); n λis the refractive index of monochromatic non-modulated light under standard meteorological conditions, and its calculation formula is given by Barrell-Sears: (4-3) From the above formula, we can get: (4-4) From the above formula we can get (4-5) For the millimeter wave radar used in this project, its wavelength is λ= 5000μm, so the above formula can be n g Substituting into the refractive index calculation formula, we can get: (4-6) In millimeter-wave radar measurement, air pressure is generally measured in millibars (mb), and the above formula can be rewritten as: (4-7) The standard meteorological conditions for the millimeter wave radar of this project can be stipulated as follows: dry temperature t =12℃, atmospheric pressure P =1013.25mb, relative humidity h =60% (humidity temperature is 8.3°C), the base refractive index can be calculated n 0=1+276.5×10 -6 .set up: (4-8) (4-9) The meteorological correction formula for the effect of atmospheric refractive index on ranging is: (4-10) Where, is the distance to be measured. At this point, a meteorological correction model related to millimeter-wave radar ranging can be established using factors such as the Euclidean distance to be measured, temperature, air pressure, and humidity. The ranging value, after being corrected for range compensation, horizontal angle, and elevation angle compensation, is corrected using the meteorological correction model formula (2-40).

[0031] S5. Obtain the initial coordinates based on the original radar data of S1, and use the ranging error compensation model of S2, the millimeter-wave radar angle error model of S3, and the meteorological correction model of S4 to obtain the corrected precise distance observation value. According to the influence of single-pulse measurement error, distance length, and signal-to-noise ratio on the measurement, a high-precision measurement model of millimeter-wave radar that takes into account multiple influencing factors is constructed. The high-precision measurement model of millimeter-wave radar is used to obtain high-precision measurement data of millimeter-wave radar that takes into account multiple influencing factors.

[0032] Further preferably, in S5, the constructing of a millimeter wave radar high-precision measurement model taking into account multiple influencing factors includes: S501, setting the approximate coordinates of any corner reflector, and expanding it according to Taylor series to obtain the millimeter wave distance observation value of the corner reflector; S502, using nonlinear least squares estimation to calculate correction values ​​of unknown parameters based on the observation equation when i radars simultaneously observe the same target at any time and the obtained millimeter wave range observation value; S503. Based on the difference in measurement accuracy of single-observation radar pulses, the true distance, and the signal-to-noise ratio, comprehensive weighting is performed to establish a high-precision measurement model for millimeter-wave radar that takes into account multiple influencing factors, and to calculate the approximate coordinates of the corner reflector.

[0033] Further preferably, in S501, the approximate coordinates of any corner reflector are set, and the millimeter wave distance observation value of the corner reflector is obtained according to Taylor series expansion, including: Assume the approximate coordinates of any corner reflector to be , the coordinates of the i-th radar are ,exist The first-order Taylor series expansion at is: in, represents the millimeter wave distance observation value; Indicates the true value of the geometric distance from the millimeter wave radar to the angle reflector; , , All are intermediate variables; , , ; 、 、 They are 、 、 The coordinate increment for the direction.

[0034] Further preferably, in S502, according to the observation equation when i radars simultaneously observe the same target at any time and the obtained millimeter wave range observation value, nonlinear least squares estimation is used to calculate the correction value of the unknown parameter, which includes: The observation equation is , make , The observation equation can be abbreviated as ;

[0035] Use nonlinear least squares estimation to calculate the corrected values ​​of the unknown parameters: Where, is the initial value of the parameter to be estimated, that is, the approximate value of the target coordinate ; is the parameter correction number obtained; Estimate the parameters obtained each time; is the weight matrix.

[0036] Further preferably, in S503, when performing comprehensive weighting based on the single observation radar pulse measurement accuracy difference, the true distance, and the signal-to-noise ratio, the weighting formula is as follows: Where, The intermediate variable is calculated to integrate the difference in single observation radar pulse measurement accuracy, true distance and signal-to-noise ratio, i=1, 2, …, n, where n is the number of millimeter-wave radars. ; is the true distance of the i-th radar to the target j at the k-th epoch; is the pulse measurement accuracy difference of target j by the i-th radar at epoch k; is the signal-to-noise ratio of the i-th radar to the target j at epoch k.

[0037] The constructed ranging error model, angle error model, and meteorological error model are used to correct the radar ranging value to obtain accurate distance observation values. Combined with the millimeter-wave radar angle measurement method, a preliminary estimate of the approximate coordinates of the corner reflector is achieved. The calculation formula is as follows: Where, is the distance between the radar and the corner reflector, that is, the corrected radar ranging value; is the azimuth angle of the corner reflector; is the elevation angle of the corner reflector, which is obtained by direct radar measurement.

[0038] Where, The phase difference of the echo signals from different receiving antennas, is the distance between different receiving antennas.

[0039] The millimeter-wave radar measurement method disclosed in this application, which takes into account multiple influencing factors, can effectively solve the shortcomings of the existing technology. The present invention uses the FFT frequency method and CZT to refine the ranging value within the accuracy range. To address the problem of insufficient millimeter-wave radar ranging accuracy, the present invention analyzes the correlation between distance and radar electronic component delay, true distance, angle-related errors, and meteorological factors, constructs a ranging error refinement compensation model, and obtains the radar's accurate ranging value for the target; based on the distance, azimuth, and pitch angle compensated by the radar and the corner reflector, the target is roughly located. A precise random model is established by combining the measurement accuracy difference of the single-observation radar pulse, the true distance, and the signal-to-noise ratio. The spatial distance intersection method is used to measure the position of the corner reflector to achieve millimeter-level rapid measurement of the track geometry in the tunnel. The present invention solves the problem of relying on foreign total station equipment for measurement in railway tunnels, improves the efficiency and accuracy of millimeter-wave radar measurement in complex tunnel environments, and effectively saves measurement costs.

[0040] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A millimeter wave radar measurement method taking into account multiple influencing factors, characterized in that: The following steps are involved: S1. Obtaining raw radar data and performing fine processing on the obtained raw radar data to obtain the precise distance measurement value of a single radar to the target; S2. Set the azimuth and elevation angles of the radar transmitter to 0; and construct a ranging error compensation model. S3, alternately transforming the azimuth and elevation angles of the radar to the angle transmitter to construct a millimeter wave radar angle error model; S4. Using the ranging error model and the angle error model, the distance obtained by the radar measuring the corner reflector is compensated, the temperature and humidity near the radar are measured using a thermohygrometer, the relationship between the temperature, humidity and the compensated distance is analyzed, and a meteorological correction model is constructed; S5. Obtain the initial coordinates based on the original radar data of S1, and use the ranging error compensation model of S2, the millimeter-wave radar angle error model of S3, and the meteorological correction model of S4 to obtain the corrected precise distance observation value. According to the influence of single-pulse measurement error, distance length, and signal-to-noise ratio on the measurement, a high-precision measurement model of millimeter-wave radar that takes into account multiple influencing factors is constructed. The high-precision measurement model of millimeter-wave radar is used to obtain high-precision measurement data of millimeter-wave radar that takes into account multiple influencing factors.

2. The millimeter wave radar measurement method taking into account multiple influencing factors according to claim 1, characterized in that: In S1, the refined processing of the acquired raw radar data to obtain the precise distance measurement value of a single radar to the target includes: S101, coarse extraction of distance values ​​includes taking the corner reflector as a target, calculating the frequency of discrete beat signals in the original radar data using FFT, selecting the frequency corresponding to the signal with the maximum amplitude, and converting it to obtain the target radial distance; S102, spectrum refinement, including coarse extraction of the target radial distance, determining the frequency corresponding to the target between the left and right adjacent spectrum lines of the maximum spectrum line, and using CZT to refine the spectrum line to obtain the unambiguous phase of the target; S103: Refine the distance measurement value by calculating the phase difference between the two distance measurements based on the unambiguous phase of the target and converting the phase difference into the corresponding distance change. ,Will By adding it to the first distance measurement value, the precise distance measurement value of the next epoch can be obtained.

3. The millimeter wave radar measurement method considering multiple influencing factors according to claim 1, characterized in that: In S2, the azimuth and elevation angles of the radar transmitter are set to 0; a ranging error compensation model is constructed, including: The pitch angle and horizontal angle of the radar antenna and corner reflector were adjusted to 0°. The corner reflector was linearly translated 2000 times from 0.5m to 200m in steps of 0.1m. The true absolute distance between the radar and the corner reflector was obtained as the true value. The difference between the distance and the distance measured by the radar and the corner reflector was used to obtain the optimal linear function model with the true value, which was used as the ranging error compensation model.

4. The millimeter wave radar measurement method taking into account multiple influencing factors according to claim 3 is characterized in that: In S3, the azimuth and elevation angles of the radar transmitter are alternately transformed to construct the millimeter-wave radar angle error model, including: The pitch angle between the radar and the corner reflector was fixed at 0°, and the horizontal angle was rotated from -60° to 60° in 5° steps for 25 times. The measured value obtained by the ranging error compensation model was subtracted from the true value to construct an optimal function model between the error and the horizontal angle. The horizontal angle is fixed at 0°, and the pitch angle is rotated from -30° to 30° with a step size of 5° for a total of 13 times. The measured value obtained by the ranging error compensation model is subtracted from the true value to construct an optimal function model between the error and the pitch angle.

5. The millimeter wave radar measurement method considering multiple influencing factors according to claim 1, characterized in that: In S4, the temperature and humidity near the radar are measured using a thermohygrometer, the relationship between the temperature, humidity and the compensated distance is analyzed, and the weather correction model is constructed, which includes the following steps: Select any distance within 200m from the radar, use a temperature and humidity meter and a timed photography program to measure the real-time meteorological factors on site, including temperature and humidity values; Correcting the radar ranging value in sequence using the ranging error compensation model and the millimeter-wave radar angle error model to obtain a compensated radar ranging distance; The temperature value, humidity value and radar ranging distance are used to construct a mapping relationship matrix between real-time weather and corrected ranging values ​​to form a weather correction model.

6. The millimeter wave radar measurement method considering multiple influencing factors according to claim 1, characterized in that: In S5, the millimeter wave radar high-precision measurement model that takes into account multiple influencing factors is constructed, including: S501, setting the approximate coordinates of any corner reflector, and expanding it according to Taylor series to obtain the millimeter wave distance observation value of the corner reflector; S502, using nonlinear least squares estimation to calculate correction values ​​of unknown parameters based on the observation equation when i radars simultaneously observe the same target at any time and the obtained millimeter wave range observation value; S503. Based on the difference in measurement accuracy of single-observation radar pulses, the true distance, and the signal-to-noise ratio, comprehensive weighting is performed to establish a high-precision measurement model for millimeter-wave radar that takes into account multiple influencing factors, and to calculate the approximate coordinates of the corner reflector.

7. The millimeter wave radar measurement method considering multiple influencing factors according to claim 6, characterized in that: In S501, the approximate coordinates of any corner reflector are set, and the millimeter wave distance observation value of the corner reflector is obtained according to Taylor series expansion, including: Assume the approximate coordinates of any corner reflector to be , the coordinates of the i-th radar are ,exist The first-order Taylor series expansion at is: in, represents the millimeter wave distance observation value; Indicates the true value of the geometric distance from the millimeter wave radar to the angle reflector; , , All are intermediate variables; , , ; 、 、 They are 、 、 The coordinate increment for the direction.

8. The millimeter wave radar measurement method considering multiple influencing factors according to claim 7, characterized in that: In S502, based on the observation equation when i radars simultaneously observe the same target at any time and the obtained millimeter wave range observation value, nonlinear least squares estimation is used to calculate the correction value of the unknown parameter, including: The observation equation is , make ， The observation equation can be abbreviated as ; Use nonlinear least squares estimation to calculate the corrected values ​​of the unknown parameters: Where, is the initial value of the parameter to be estimated, that is, the approximate value of the target coordinate ; is the parameter correction number obtained; Estimate the parameters obtained each time; is the weight matrix.

9. The millimeter wave radar measurement method considering multiple influencing factors according to claim 6, characterized in that: In S503, based on the single observation radar pulse measurement accuracy difference, the actual distance and the signal-to-noise ratio, a comprehensive weighting is performed, and the weighting formula is as follows: Where, The intermediate variable is calculated to integrate the difference in single observation radar pulse measurement accuracy, true distance and signal-to-noise ratio, i=1, 2, …, n, where n is the number of millimeter-wave radars. ; is the true distance of the i-th radar to the target j at the k-th epoch; is the pulse measurement accuracy difference of target j by the i-th radar at epoch k; is the signal-to-noise ratio of the i-th radar to the target j at epoch k.

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