CN114966579A - Method and device for acquiring calibration parameters of radar system - Google Patents

Method and device for acquiring calibration parameters of radar system Download PDF

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Publication number
CN114966579A
CN114966579A CN202210568527.9A CN202210568527A CN114966579A CN 114966579 A CN114966579 A CN 114966579A CN 202210568527 A CN202210568527 A CN 202210568527A CN 114966579 A CN114966579 A CN 114966579A
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target detection
point
radar
target
amplitude
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冀广宇
李毅之
董勇伟
景毅
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Zhongke Yuda Beijing Technology Co ltd
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Zhongke Yuda Beijing Technology Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
    • G01S7/4026—Antenna boresight
    • G01S7/403—Antenna boresight in azimuth, i.e. in the horizontal plane
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
    • G01S7/4026—Antenna boresight
    • G01S7/4034—Antenna boresight in elevation, i.e. in the vertical plane
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4052—Means for monitoring or calibrating by simulation of echoes
    • G01S7/4082—Means for monitoring or calibrating by simulation of echoes using externally generated reference signals, e.g. via remote reflector or transponder
    • G01S7/4091—Means for monitoring or calibrating by simulation of echoes using externally generated reference signals, e.g. via remote reflector or transponder during normal radar operation

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  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The invention provides a method and a device for acquiring calibration parameters of a radar system, relates to the technical field of radars, and solves the problem that the target detection precision of a radar during working cannot be ensured after the low-altitude target detection radar is arranged in different places. The method comprises the following steps: acquiring a target measurement point track result of a flight track of the unmanned aerial vehicle in the flight process; acquiring a target detection trace result obtained by the radar performing target detection processing according to an echo signal reflected by the unmanned aerial vehicle, and determining a target detection point according to the target measurement trace result and the target detection trace result; according to the target detection point, determining a calibration parameter of the radar, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation. The scheme of the invention realizes that the obtained calibration parameters reach the optimum, and improves the target detection precision of the radar during working.

Description

Method and device for obtaining calibration parameters of radar system
Technical Field
The invention relates to the technical field of radars, in particular to a method and a device for acquiring calibration parameters of a radar system.
Background
The low-altitude target detection radar can effectively detect low-altitude and low-speed small targets with the characteristics of low flying height, low flying speed and small target size for unmanned aerial vehicles and the like, can acquire the position, speed and other information of the targets in real time and has the tracking capability, and is a powerful tool for preventing illegal low-altitude flying behaviors and guarding low-altitude safety.
When the low-altitude target detection radar detects a low-altitude target, the low-altitude target detection radar has a high requirement on the accuracy of the position of the target, which requires calibration processing of radar system parameters, and the obtained calibration parameters are used for signal processing of the radar system during operation.
The common system calibration scheme mostly adopts an intra-system calibration method, which forms an intra-calibration loop in the radar system to obtain intra-calibration parameters and keeps the intra-calibration parameters unchanged after the radar system is integrated. However, in the application, the low-altitude target detection radar works by changing a plurality of places. When the low-altitude target detection radar is arranged in different places, certain deviation exists between the installation direction and the angle of a radar antenna array surface, the difference of the replacement and installation of a cable between a connection radar antenna and a radio frequency can lead to the difference of the amplitude-phase characteristics of each receiving channel, the radar scaling parameters for subsequent signal processing are changed, and the target detection precision of the radar in working can not be guaranteed.
Disclosure of Invention
The invention aims to provide a method and a device for acquiring calibration parameters of a radar system. The obtained calibration parameters can be optimized, and the target detection precision of the radar during working is improved.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a method for obtaining calibration parameters of a radar system comprises the following steps:
acquiring a target measurement point track result of a flight track of the unmanned aerial vehicle in the flight process;
obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle;
determining target detection points according to the target measurement trace results and the target detection trace results;
according to the target detection point, determining a calibration parameter of the radar, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
Optionally, obtaining a target measurement point track result of a flight track of the unmanned aerial vehicle in a flight process includes:
acquiring position information of each sampling point in a flight track of the unmanned aerial vehicle in the flight process;
and calculating the distance between each sampling point and the radar and the azimuth angle and the pitch angle of each sampling point position relative to the normal direction of the radar antenna array surface according to the position information of the sampling points and the position information of the center of the radar antenna array surface to obtain the target measurement trace point result.
Optionally, obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle includes:
acquiring 4 paths of echo signals reflected by the unmanned aerial vehicle and received by the radar, wherein 1 path of echo signal corresponds to 1 antenna array surface of the radar;
respectively using amplitude and phase correction coefficients for 4 paths of echo signals reflected by the unmanned aerial vehicle
Figure BDA0003658135900000021
Carrying out target detection processing to obtain 4 groups of target detection trace results;
the distance information D of the target detection points detected in the 4 groups of target detection point trace results j And amplitude information of each channel
Figure BDA0003658135900000022
And phase information
Figure BDA0003658135900000023
Detecting a trace result as the target;
wherein j is the serial number of the target detection points and takes the value of 1-N, and N is the number of the target detection points;
i is a channel number, i is 1, 2, 3 and 4, and represents the number of a 4-channel, and a superscript (0) represents the initial values of the amplitude-phase information and the amplitude-phase correction coefficient.
Optionally, determining a target detection point according to the target measurement trace result and the target detection trace result includes:
performing feature matching on the target measurement trace result and the target detection trace result through the flight trajectory of the unmanned aerial vehicle, and determining a plurality of matched target detection points; the matched parameter information of each target detection point comprises distance information D of the target detection point relayed from a target measurement trace result j Amplitude information of each channel
Figure BDA0003658135900000024
Phase information of each channel
Figure BDA0003658135900000025
And GPS measured azimuth by matching from corresponding target measured trace results
Figure BDA0003658135900000026
Measuring pitch angle theta with GPS j 。
Optionally, determining a calibration parameter of the radar according to the target detection point includes:
obtaining the distance deviation of target detection points in each channel;
correcting the amplitude-phase coefficient of the target detection point in each channel to obtain an amplitude-phase correction coefficient result and a fitting slope of the phase correction coefficient of each channel;
according to the amplitude-phase correction coefficient of the target detection points at the distance average value of all the target detection points, the distance information in the target detection points is used for carrying out target detection processing on the original echo signal to obtain a detection result;
acquiring azimuth angle deviation and pitch angle deviation of a target detection point in the detection result;
judging whether the fitting slope of the phase correction coefficient is smaller than or equal to a preset threshold value, whether the azimuth angle deviation and the pitch angle deviation of each target detection point are consistent, judging whether the iteration times of the method enable the azimuth angle deviation to be converged within the range of the azimuth angle threshold value and enable the pitch angle deviation to be converged within the range of the pitch angle threshold value, and if one or more judgment results are negative, carrying out iteration processing according to the updated parameter duplication step; if the judgment results are yes, stopping the iterative processing of the step, and outputting a calibration parameter, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
Optionally, obtaining the distance deviation of the target detection point in each channel includes:
respectively drawing a distance-sampling time two-dimensional graph of the trace point according to respective distance coordinates and time coordinates of the target measurement trace point result and the target detection trace point result;
and when the point traces on the two-dimensional graph are superposed, determining the distance of the target detection point trace translated along the distance axis as the distance deviation of the target detection point.
Optionally, the step of performing correction processing on the amplitude-phase coefficient of the target detection point in each channel to obtain the result of the amplitude-phase correction coefficient and the fitting slope of the phase correction coefficient of each channel includes:
by the following formula:
Figure BDA0003658135900000031
Figure BDA0003658135900000032
Figure BDA0003658135900000033
Figure BDA0003658135900000034
correcting the amplitude and phase coefficient of the target detection point in each channel to obtain an amplitude and phase correction coefficient result II
Wherein d is x For azimuthal antenna phase center spacing, d z To pitch towards the antenna phase center spacing,
Figure BDA0003658135900000041
n is the amplitude correction coefficient calculated at each target detection point in the kth iteration,
Figure BDA0003658135900000042
n is the phase correction coefficient calculated for each target detection point in the k-th iteration,
Figure BDA0003658135900000043
measuring azimuth angle theta for GPS in parameter information of each target detection point j The pitch angle is adopted, and lambda is a preset constant and represents the working wavelength of the radar;
all phase correction coefficient results obtained by calculation according to target detection points in each channel
Figure BDA0003658135900000044
Performing one-dimensional phase unwrapping and linear fitting by taking the distance Dj in the parameter information of the target detection point as an independent variable to obtain a fitting slope
Figure BDA0003658135900000045
As the fitting slope of the acquired phase correction coefficient of each channel.
Optionally, the performing target detection processing on the original echo signal according to the amplitude-phase correction coefficient of the target detection point at the distance average of all the target detection points based on the distance information in the target detection points to obtain a detection result includes:
selecting distance information D in the parameter information of each target detection point j For points at the mean distance as selectedMarking detection points;
using the amplitude-phase correction coefficient calculated by the parameter information of the selected target detection point
Figure BDA0003658135900000046
Figure BDA0003658135900000047
Carrying out target detection processing on 4 paths of original echo data to obtain a detection result, wherein the detection result is parameter information of each target detection point after one iteration and comprises distance information D of the target detection points j Amplitude information of each channel
Figure BDA0003658135900000048
Phase information of each channel
Figure BDA00036581359000000417
And radar measurement azimuth angle obtained by 4-channel sum and difference beam measurement method
Figure BDA00036581359000000410
Measuring pitch angle with radar
Figure BDA00036581359000000411
Optionally, obtaining the azimuth angle deviation and the pitch angle deviation of the target detection point in the detection result includes:
measuring the azimuth angle of the radar of each target detection point in the detection result
Figure BDA00036581359000000412
And radar measurement of pitch angle
Figure BDA00036581359000000413
And the GPS measurement azimuth angle in the parameter information of the corresponding target detection point
Figure BDA00036581359000000414
And GPS measures pitch angle theta j By comparison, obtainTaking the azimuth deviation of each target detection point
Figure BDA00036581359000000415
Deviation from pitch angle
Figure BDA00036581359000000416
The embodiment of the present invention further provides an apparatus for obtaining a calibration parameter of a radar system, including:
the first acquisition module is used for acquiring a target measurement point track result of a flight track of the unmanned aerial vehicle in the flight process;
the second acquisition module is used for acquiring a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle;
the processing module is used for determining target detection points according to the target measurement trace results and the target detection trace results; and obtaining a calibration parameter of each target detection point, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
The scheme of the invention at least comprises the following beneficial effects:
according to the scheme, the flight path of the unmanned aerial vehicle in the flight process is obtained, and the radar carries out target detection processing according to the echo signal reflected by the unmanned aerial vehicle, so that a target measurement trace result and a target detection trace result are obtained respectively; determining target detection points according to the target measurement trace results and the target detection trace results; and finally, determining the calibration parameters of the radar according to the target detection point: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation; the calibration method can realize the quick calibration of the calibration parameters of the radar system at a new place after the radar moves, and improve the target detection precision of the radar during working.
Drawings
FIG. 1 is a flow chart of a method for obtaining calibration parameters of a radar system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the matching result of the two-dimensional distance-time diagram of the flight trajectory of the unmanned aerial vehicle in the embodiment of the invention;
FIG. 3 is a diagram illustrating phase correction coefficients and linear fitting results obtained from target detection points after 4 iterations in an embodiment of the present invention;
FIG. 4 is a comparison graph of a target detection angle measurement result and a target GPS measurement true value result obtained after echo data is processed by using calibration parameters obtained by 4 times of iterative processing in the embodiment of the present invention;
FIG. 5 is a flowchart illustrating an implementation of a method for obtaining calibration parameters of a radar system according to an embodiment of the present invention;
fig. 6 is a schematic block diagram of a device for obtaining calibration parameters of a radar system according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
As shown in fig. 1, an embodiment of the present invention provides a method for obtaining a calibration parameter of a radar system, including the following steps:
step 11, obtaining a target measurement point track result of a flight track of the unmanned aerial vehicle in a flight process, wherein the target measurement point track result comprises: the distance between each sampling point on the flight track and the center of the radar antenna array surface and the azimuth angle and the pitch angle of each sampling point relative to the normal direction of the radar antenna array surface;
step 12, obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle, wherein the target detection trace result comprises: distance information, amplitude information and phase information of each channel of the target detection point;
step 13, determining target detection points according to the target measurement trace results and the target detection trace results;
step 14, determining a calibration parameter of the radar according to the target detection point, wherein the calibration parameter includes: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
According to the embodiment of the invention, the position information of the flight track of the unmanned aerial vehicle is obtained through a GPS (global positioning system) of the unmanned aerial vehicle, sampling points are extracted according to the position information of the flight track, the distance between each target sampling point and the center of a radar antenna array surface, the azimuth angle and the pitch angle are calculated, and a target measurement point track result is formed; meanwhile, the radar irradiates the flight process of the unmanned aerial vehicle to obtain an echo signal, and a target detection trace result of the radar is obtained by performing target detection processing on the echo signal; and performing characteristic matching on the target measurement trace result and the target detection trace result through the flight track of the unmanned aerial vehicle to determine a plurality of target detection points, and processing and comparing the target detection points to obtain calibration parameters of the radar system. The low-altitude target detection radar arranged at the working position can be calibrated, the calibration parameters acquired by the mode of repeated iteration processing are used for target detection processing by acquiring target echo information of the cooperative unmanned aerial vehicle with the real-time GPS position, the precision of a target detection result is improved, and the accuracy of the low-altitude flight target detection result is ensured.
In an optional embodiment of the present invention, in step 11, obtaining a target measurement point trajectory result of a flight trajectory of an unmanned aerial vehicle in a flight process includes:
111, acquiring position information of each sampling point in a flight track of the unmanned aerial vehicle in the flight process;
and 112, calculating the distance between each sampling point and the radar and the azimuth angle and the pitch angle of each sampling point relative to the normal direction of the radar antenna array according to the position information of the sampling points and the position information of the center of the radar antenna array to obtain the target measurement trace point result.
In this embodiment, a drone aircraft flies in a specific manner in the direction of the normal to the antenna illumination of the low-altitude target detection radarWhen the unmanned aerial vehicle is used as a target, a GPS module carried by the unmanned aerial vehicle records the position information of the flight track of the unmanned aerial vehicle during the flight process; extracting each sampling point qm of the unmanned aerial vehicle in a flight track according to GPS data recorded in the flight process of the unmanned aerial vehicle, wherein M is 1, 2. Each target sampling point q m The position information including the point, namely longitude, latitude and altitude information, calculates each target sampling point q according to the measured radar array center position information and the nominal normal direction thereof m Distance D from radar m Azimuth angle
Figure BDA0003658135900000071
To the pitch angle theta m Forming a target measurement trace result;
the specific implementation mode of flying a non-human-machine cooperation target in a specific mode is as follows: the unmanned aerial vehicle flies from near to far and then from far to near approximately along the normal direction of the antenna, and the unmanned aerial vehicle swings left and right along the azimuth direction and swings up and down along the pitching direction within the irradiation range of the radar antenna beam in the flying process.
In an optional embodiment of the present invention, in step 12, obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle includes:
step 121, obtaining 4 paths of echo signals reflected by the unmanned aerial vehicle and received by the radar, wherein 1 path of echo signal corresponds to 1 antenna array surface of the radar;
step 122, using amplitude and phase correction coefficients for 4 paths of echo signals reflected by the unmanned aerial vehicle respectively
Figure BDA0003658135900000076
Carrying out target detection processing to obtain 4 groups of target detection trace results;
step 123, the distance information D of the detected target detection points in the 4 groups of target detection point trace results is obtained j And amplitude information of each channel
Figure BDA0003658135900000073
And phase information
Figure BDA0003658135900000074
Detecting a trace result as the target; wherein j is the serial number of the target detection points and takes the value of 1-N, and N is the number of the target detection points;
i is a channel number, i is 1, 2, 3 and 4, and represents the number of a 4-channel, and a superscript (0) represents the initial values of the amplitude-phase information and the amplitude-phase correction coefficient.
In the embodiment, target detection processing is performed on 4 paths of unmanned aerial vehicle target echo data acquired and recorded by a radar, wherein each path of echo data corresponds to 1 antenna array surface, and when the target detection processing is performed, the amplitude and phase correction coefficient of each path of echo data
Figure BDA0003658135900000075
Setting the initial values to be 0, and obtaining 1 group of target detection trace results after processing; extracting target detection points detected in the 4 groups of results from the 4 groups of target detection point trace results to serve as finally obtained target detection point trace results, and marking the extracted target detection points as p j Wherein j is the serial number of the target detection points, the value is 1-N, and N is the number of the target detection points; each target detection point p j Including distance information D of target detection points j And amplitude information of each channel
Figure BDA0003658135900000081
And phase information
Figure BDA0003658135900000082
Wherein i is a channel serial number, the value is 1-4, the serial numbers of the 4 channels are represented, and an upper corner mark (0) represents initial values of amplitude-phase information and amplitude-phase correction coefficients;
the radar has 4 antenna arrays corresponding to 4 receiving channels. The central positions of the 4 antenna array surfaces are arranged in a 2 multiplied by 2 mode along the azimuth direction and the elevation direction, and the central positions of the antenna array surfaces corresponding to the receiving channels No. 1, No. 2, No. 3 and No. 4 are respectively positioned at the upper left corner, the upper right corner, the lower left corner and the lower right corner based on the direction facing the antenna array surfaces.
In the embodiment, the specific implementation flow of the target detection processing includes amplitude and phase correction, pulse compression processing, multi-pulse cancellation processing, doppler sharpening processing, CFAR detection processing, and difference beam angle measurement processing on radar echo data, so as to obtain a detected target detection point, and distance, azimuth angle, pitch angle, radial velocity, amplitude and phase information of each channel and amplitude and phase information after channel and difference beam synthesis of the point. And performing amplitude-phase correction on the radar echo data to obtain a processing result after performing complex multiplication on the radar echo data of each channel and the amplitude-phase correction coefficient of the corresponding channel respectively.
In an optional another embodiment of the present invention, in step 13, determining a target detection point according to the target measurement trace result and the target detection trace result includes:
performing feature matching on the target measurement trace result and the target detection trace result through the flight trajectory of the unmanned aerial vehicle, then performing point-by-point matching on the two sets of trace results, and determining a plurality of matched target detection points; each target detection point p after matching j The parameter information comprises the distance information D of the target detection point relayed from the target measurement trace result j Amplitude information of each channel
Figure BDA0003658135900000083
Phase information of each channel
Figure BDA0003658135900000084
And GPS measured azimuth by matching from corresponding target measured trace results
Figure BDA0003658135900000085
Measuring pitch angle theta with GPS j 。
And setting the deviation of the central azimuth angle of the antenna
Figure BDA0003658135900000086
Deviation of pitch angle theta from the center of the antenna corr Are all 0 °, i.e.
Figure BDA0003658135900000087
The unmanned aerial vehicle flight trajectory feature matching in the embodiment specifically comprises the following steps: and (4) respectively drawing a two-dimensional figure of distance-sampling time of the traces according to respective distance coordinates and time coordinates by using the results of the target detection traces of the radar in the step S23 and the results of the target measurement traces in the step S112, comparing the shapes of the traces of the two figures, and translating the two traces on a two-dimensional plane to enable the traces of the two figures to be overlapped so as to realize the characteristic matching of the flight trace of the unmanned aerial vehicle.
In an optional another embodiment of the present invention, in step 14, determining a calibration parameter of the radar according to the target detection point includes:
step 141, obtaining distance deviations of target detection points in each channel;
step 142, correcting the amplitude and phase coefficients of the target detection points in each channel to obtain amplitude and phase correction coefficient results and fitting slopes of the phase correction coefficients of each channel;
step 143, performing target detection processing on the original echo signal according to the amplitude-phase correction coefficient of the target detection points at the distance average value of all the target detection points, wherein the distance information in the target detection points is the target detection point, and obtaining a detection result;
step 144, acquiring an azimuth angle deviation and a pitch angle deviation of a target detection point in the detection result;
step 145, determining whether the fitting slope of the phase correction coefficient is less than or equal to a preset threshold, whether the azimuth angle deviation and the pitch angle deviation of each target detection point are consistent, and whether the iteration number of the method enables the azimuth angle deviation to converge to the azimuth angle threshold
Figure BDA0003658135900000091
In-range and convergence of pitch angle deviation to pitch angle threshold θ th Within the range, if one or more of the judgment results are negative, the step is repeated according to the updated parameters to carry out iterative processing; if it is aboveIf yes, stopping the iterative processing of the step, and outputting a calibration parameter, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
In this embodiment, step 141 may specifically include:
step 1411, drawing a distance-sampling time two-dimensional graph of traces according to respective distance coordinates and time coordinates of the target measurement trace results and the target detection trace results;
and step 1412, when the point traces on the two-dimensional graph are overlapped, determining the distance of the target detection point trace translated along the distance axis as the distance deviation of the target detection point.
As shown in fig. 2, a two-dimensional distance-sampling time graph of traces is drawn according to respective distance coordinates and time coordinates from the result of measuring traces by the target in step 112 and the result of detecting traces by the target in step 123; when the point traces on the two-dimensional graph are superposed, the distance of the target detection point trace translated along the distance axis is determined as the distance deviation of the target detection point, so that the distance calibration result of the target detection point, namely the distance deviation D, is obtained corr . For example, the distance of translation of the target detection point trace along the distance axis is 1.3m, i.e., the distance deviation D of the target detection points corr Is 1.3 m.
Further, step 142 may specifically include:
by the following formula:
Figure BDA0003658135900000092
Figure BDA0003658135900000101
Figure BDA0003658135900000102
Figure BDA0003658135900000103
correcting the amplitude-phase coefficient of the target detection point in each channel to obtain an amplitude-phase correction coefficient result;
wherein d is x For azimuthal antenna phase center spacing, d z To pitch towards the antenna phase center spacing,
Figure BDA0003658135900000104
n is the amplitude correction coefficient calculated for each target detection point in the kth iteration,
Figure BDA0003658135900000105
n is the phase correction coefficient calculated for each target detection point in the k-th iteration,
Figure BDA0003658135900000106
measuring azimuth angle theta for GPS in parameter information of each target detection point j And measuring a pitch angle for the GPS in the parameter information of each target detection point, wherein lambda is a preset constant and represents the working wavelength of the radar.
Then all phase correction coefficient results obtained by calculation according to target detection points in each channel are obtained
Figure BDA0003658135900000107
By the distance D of the target detection point j One-dimensional phase unwrapping and linear fitting are carried out on the independent variable to obtain the fitting slope of the phase correction coefficient of each channel
Figure BDA0003658135900000108
And fitting phase offset
Figure BDA0003658135900000109
Further, step 143 may specifically include:
step 1431, select each target detection point p ij Distance information D in parameter information j Is the point p at which the distance average is iJ Will point p iJ As a selected target detection point;
step 1432, use p iJ The amplitude-phase correction coefficient obtained by calculating the parameter information
Figure BDA00036581359000001010
Target detection processing is carried out on 4 paths of original echo data to obtain a target detection point p j The parameter information after one iteration comprises the distance information D of the target detection point j Amplitude information of each channel
Figure BDA00036581359000001011
Phase information of each channel
Figure BDA00036581359000001012
And radar measurement azimuth angle obtained by 4-channel sum and difference beam measurement method
Figure BDA00036581359000001013
Measuring pitch angle with radar
Figure BDA00036581359000001014
In this embodiment, a target detection point p is selected ij Distance information D of midpoints j Is the point p at the mean value of the distance iJ Using p iJ The information of the phase correction coefficient is calculated
Figure BDA00036581359000001015
Expressed as:
Figure BDA0003658135900000111
using amplitude-phase correction coefficients
Figure BDA0003658135900000112
Target detection processing is carried out on 4 paths of original echo data to obtain a target detection point p j The parameter information after one iteration comprises distance information D of the target detection point j Amplitude of each channelInformation
Figure BDA0003658135900000113
Phase information of each channel
Figure BDA0003658135900000114
Wherein exp (·) represents an exponential function based on the natural logarithm e; and radar measurement azimuth angle obtained by 4-channel sum and difference beam measurement method
Figure BDA0003658135900000115
Measuring pitch angle with radar
Figure BDA0003658135900000116
Step 144 may specifically include: measuring the azimuth angle by radar
Figure BDA0003658135900000117
And a pitch angle
Figure BDA0003658135900000118
And GPS measurement results
Figure BDA0003658135900000119
And theta j Comparing to obtain the azimuth angle deviation of each point
Figure BDA00036581359000001125
Deviation from pitch angle
Figure BDA00036581359000001111
Specifically, the azimuth angle obtained by radar measurement
Figure BDA00036581359000001112
And a pitch angle
Figure BDA00036581359000001113
Results and GPS measurements
Figure BDA00036581359000001114
And theta j Respectively corresponding difference making to obtain the azimuth angle deviation of each target detection point
Figure BDA00036581359000001115
Deviation from pitch angle
Figure BDA00036581359000001116
Wherein, i is a channel serial number, i is 1, 2, 3, 4, which indicates the serial number of the 4-channel, j is the serial number of the target detection point, and the value is 1-N, and N is the number of the target detection points.
In step 145, the slope of the phase correction coefficient is determined
Figure BDA00036581359000001117
Whether the value is less than the threshold value K th Deviation of azimuth angle of each point
Figure BDA00036581359000001118
Deviation from pitch angle
Figure BDA00036581359000001119
Whether they are consistent and respectively converge to
Figure BDA00036581359000001120
And theta th If not, repeating the step 14 to enter the next iteration process; if yes, ending iteration and outputting a calibration parameter, wherein the calibration parameter comprises: amplitude-phase correction coefficient
Figure BDA00036581359000001126
Deviation of azimuth angle
Figure BDA00036581359000001122
Deviation of pitch angle
Figure BDA00036581359000001123
And a distance deviation D corr And n is the iteration number when the iteration is ended.
Fig. 3 shows the phase correction coefficients and their linear fitting results for each channel after 4 iterations. It can be seen that after 4 iterations, the slope of the phase correction factor is relatively flat, and its value is already below 0.1 °/m. After 4 iterations, the calibration parameters obtained in this embodiment are:
amplitude-phase correction coefficient of each channel:
η 1 ＝1，η 2 ＝-0.55+0.60j，η 3 ＝-0.42-0.82j，η 4 ＝-0.29-0.82j.
distance deviation: d corr ＝1.3m；
Azimuth and pitch offset:
Figure BDA00036581359000001124
θ corr ＝-7.15°；
fig. 4 shows a comparison between a target detection result obtained by processing echo data using the calibration parameters obtained after 4 iterations and a target GPS measurement true value result on a pitch angle measurement result. Therefore, the target positioning result obtained by adopting the calibration parameter processing has higher precision.
As shown in fig. 5, a flowchart of a specific implementation of the foregoing embodiment is shown, and the process includes:
51, flying an unmanned aerial vehicle cooperative target in a specific mode in the direction of an antenna irradiation normal of the low-altitude target detection radar, and recording the position information of the flying track of the unmanned aerial vehicle by a GPS module carried by the unmanned aerial vehicle in the flying process; meanwhile, the low-altitude target detection radar irradiates the unmanned aerial vehicle in the whole flight process, and 4 paths of receiving channels of the radar acquire echo data and record the echo data.
Step 52, extracting each sampling point q of the unmanned aerial vehicle in the flight track according to the GPS data recorded in the flight process of the unmanned aerial vehicle m Wherein M is 1, 2, the number of sampling points of the unmanned aerial vehicle in the flight path. Each target sampling point q m The position information including the point, namely longitude, latitude and altitude information, calculates each target sampling point q according to the measured radar array center position information and the nominal normal direction thereof m With radarA distance D between m Azimuth angle
Figure BDA0003658135900000121
To the pitch angle theta m And forming a GPS measurement trace point result of the target.
And 53, carrying out target detection processing on 4 paths of unmanned aerial vehicle target echo data acquired and recorded by the radar. Each path of echo data corresponds to 1 antenna array surface, and the amplitude-phase correction coefficient eta of each path of echo data is used for target detection processing i And i is set to be an initial value of 0, 2, 3 and 4, and 1 group of target detection trace results are obtained after processing. Extracting target detection points detected in the 4 groups of results from the 4 groups of target detection point trace results to serve as finally obtained target detection point trace results, and marking the extracted target detection points as p j Wherein j is the serial number of the target detection points, the value is 1-N, and N is the number of the target detection points. Each target detection point p j Including distance information D of target detection points j And amplitude information of each channel
Figure BDA0003658135900000122
And phase information
Figure BDA00036581359000001210
Wherein i is a channel serial number, the value is 1-4, the serial numbers of the 4 channels are represented, and the upper corner mark (0) represents the initial value of the amplitude-phase information.
Step 54, matching the target detection point trace result measured by the radar in the step 53 with the target GPS measurement point trace result in the step 52 through the flight trace characteristics of the unmanned aerial vehicle, and obtaining a distance calibration result D of the target detection point corr . Then, the two groups of trace point results are matched point by point, so that each target detection point p is matched j Distance information D containing target detection points j Amplitude information of each channel
Figure BDA0003658135900000124
Phase information of each channel
Figure BDA00036581359000001211
GPS measurement azimuth
Figure BDA0003658135900000126
Measuring pitch angle theta with GPS j . And setting the deviation of the central azimuth angle of the antenna
Figure BDA0003658135900000127
Deviation of pitch angle theta from the center of the antenna corr Are all 0 °, i.e.
Figure BDA0003658135900000128
Step 55, matching target detection point p obtained by GPS measurement point trace and radar measurement point trace ij And (3) performing amplitude-phase coefficient correction processing point by point to obtain an amplitude-phase correction coefficient result, which is expressed as:
Figure BDA0003658135900000129
Figure BDA0003658135900000131
Figure BDA0003658135900000132
Figure BDA0003658135900000133
wherein d is x For azimuthal antenna phase center spacing, d z To pitch towards the antenna phase center spacing,
Figure BDA0003658135900000134
n is the amplitude correction factor calculated for each point in the kth iteration,
Figure BDA0003658135900000135
n is each point in the k-th iterationThe calculated phase correction coefficient.
All phase correction coefficient results obtained by calculation according to target detection points in each channel
Figure BDA0003658135900000136
One-dimensional phase unwrapping and linear fitting are carried out by taking the distance Dj of the target detection point as an independent variable to obtain the fitting slope of each channel phase correction coefficient
Figure BDA0003658135900000137
And fitting phase offset
Figure BDA0003658135900000138
Step 56, selecting target detection point p ij Distance information D of midpoints j Is the point p at which the distance average is iJ Will use p iJ Amplitude and phase correction coefficient obtained by calculating detection point information
Figure BDA0003658135900000139
Expressed as:
Figure BDA00036581359000001310
using amplitude-phase correction coefficients
Figure BDA00036581359000001311
Target detection processing is carried out on 4 paths of original echo data to obtain a target detection point p j And target detection point distance information D contained in the point j Amplitude information of each channel
Figure BDA00036581359000001312
Phase information of each channel
Figure BDA00036581359000001313
And radar measurement azimuth angle obtained by 4-channel sum and difference beam measurement method
Figure BDA00036581359000001314
Measuring pitch angle with radar
Figure BDA00036581359000001315
57, measuring the azimuth angle obtained by the radar
Figure BDA00036581359000001316
And a pitch angle
Figure BDA00036581359000001317
Results and GPS measurements
Figure BDA00036581359000001318
And theta j Comparing to obtain the azimuth angle deviation of each point
Figure BDA00036581359000001319
Deviation from pitch angle
Figure BDA00036581359000001320
Step 58, determine the slope of the phase correction coefficient of step 55
Figure BDA00036581359000001321
Whether the value is less than the threshold value K th Deviation of azimuth angle of each point
Figure BDA00036581359000001322
Deviation from pitch angle
Figure BDA00036581359000001323
Whether they are consistent and respectively converge to
Figure BDA00036581359000001324
And theta th Within the range. If not, the step S5 is repeated to enter the next iteration processing; if yes, finishing iteration, and obtaining a calibration result as follows: amplitude-phase correction coefficient
Figure BDA00036581359000001325
Deviation of azimuth angle
Figure BDA00036581359000001326
Deviation of pitch angle
Figure BDA0003658135900000141
And a distance deviation D corr And n is the iteration number when the iteration is ended.
In some embodiments of the present invention, in step 51, the low-altitude target-detecting radar has 4 antenna fronts, corresponding to 4 receive channels. The central positions of the 4 antenna array surfaces are arranged in a 2 multiplied by 2 mode along the azimuth direction and the elevation direction, and the central positions of the antenna array surfaces corresponding to the receiving channels No. 1, No. 2, No. 3 and No. 4 are respectively positioned at the upper left corner, the upper right corner, the lower left corner and the lower right corner based on the direction facing the antenna array surfaces.
In some embodiments of the present invention, in step 51, the specific implementation of flying a non-human-machine cooperation target in a specific manner is: the unmanned aerial vehicle flies from near to far (or from far to near) and then from far to near (or from near to far) approximately along the normal direction of the antenna, and the unmanned aerial vehicle can swing left and right along the azimuth direction and swing up and down along the pitching direction within the irradiation range of the radar antenna beam in the flying process.
In step 53, in the embodiment of the present invention, the target detection processing includes amplitude and phase correction, pulse compression processing, multi-pulse cancellation processing, doppler sharpening processing, CFAR detection processing, and difference beam angle measurement processing on radar echo data, so as to obtain the detected target point, and the distance, azimuth angle, pitch angle, radial velocity, amplitude and phase information of each channel and the amplitude and phase information after channel and difference beam synthesis of the point. And performing amplitude-phase correction on the radar echo data to obtain a processing result after performing complex multiplication on the radar echo data of each channel and the amplitude-phase correction coefficient of the corresponding channel respectively.
In an embodiment of the present invention, in step 54, the flight trajectory characteristics of the unmanned aerial vehicle are matched as follows: detecting the target of the radar measurement in step 53 into tracesAnd (5) respectively drawing a distance-sampling time two-dimensional graph of the traces according to respective distance coordinates and time coordinates according to the result and the target GPS measurement trace point result in the step (52), comparing the trace point shapes of the two graphs, and translating the two trace points on a two-dimensional plane to enable the trace points on the two graphs to be superposed, so that the characteristic matching of the flight trace of the unmanned aerial vehicle is realized. At this time, the distance of the target detection point trace translating along the distance axis is calculated, namely the distance calibration result D of the target detection point is obtained corr 。
The invention provides an outfield system calibration method for a low-altitude target detection radar, and the method can obtain calibration parameters of the radar under a working scene by only using a small unmanned aerial vehicle with a GPS positioning function to fly once in a radar irradiation area, acquiring and processing target echo data and finally obtaining the calibration parameters of the radar. The calibration method provided by the invention adopts an iterative processing mode, so that the acquired calibration parameters can be optimized, and the target detection precision of the radar during working is improved.
As shown in fig. 6, an embodiment of the present invention further provides an apparatus 60 for obtaining calibration parameters of a radar system, including:
the first obtaining module 61 is configured to obtain a target measurement point track result of a flight track of the unmanned aerial vehicle in a flight process;
a second obtaining module 62, configured to obtain a target detection trace result obtained by performing target detection processing on the radar according to the echo signal reflected by the unmanned aerial vehicle;
a processing module 63, configured to determine a target detection point according to the target measurement trace result and the target detection trace result; and obtaining a calibration parameter of each target detection point, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
Optionally, obtaining a target measurement point track result of a flight track of the unmanned aerial vehicle in a flight process includes:
acquiring position information of each sampling point in a flight track of the unmanned aerial vehicle in the flight process;
and calculating the distance between each sampling point and the radar and the azimuth angle and the pitch angle of each sampling point relative to the normal direction of the radar antenna array surface according to the position information of the sampling points and the position information of the center of the radar antenna array surface to obtain the target measurement trace point result.
Optionally, obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle includes:
acquiring 4 paths of echo signals reflected by the unmanned aerial vehicle and received by the radar, wherein 1 path of echo signal corresponds to 1 antenna array surface of the radar;
respectively using amplitude and phase correction coefficients for 4 paths of echo signals reflected by the unmanned aerial vehicle
Figure BDA0003658135900000151
Carrying out target detection processing to obtain 4 groups of target detection trace results;
the distance information D of the target detection points detected in the 4 groups of target detection point trace results j And amplitude information of each channel
Figure BDA0003658135900000152
And phase information
Figure BDA0003658135900000153
Detecting a trace result as the target;
wherein j is the serial number of the target detection points and takes the value of 1-N, and N is the number of the target detection points;
i is a channel number, i is 1, 2, 3 and 4, and represents the number of a 4-channel, and a superscript (0) represents the initial values of the amplitude-phase information and the amplitude-phase correction coefficient.
Optionally, determining a target detection point according to the target measurement trace result and the target detection trace result includes:
performing feature matching on the target measurement trace result and the target detection trace result through the flight trajectory of the unmanned aerial vehicle, and determining a plurality of matched target detection points; the matched parameter information of each target detection point comprises a trace point result of the target detection point measured from the targetDistance information Dj and amplitude information of each channel inherited from
Figure BDA0003658135900000154
Phase information of each channel
Figure BDA0003658135900000155
And GPS measured azimuth by matching from corresponding target measured trace results
Figure BDA0003658135900000156
Measuring pitch angle theta with GPS j 。
Optionally, determining a calibration parameter of the radar according to the target detection point includes:
obtaining the distance deviation of target detection points in each channel;
correcting the amplitude-phase coefficient of the target detection point in each channel to obtain an amplitude-phase correction coefficient result and a fitting slope of the phase correction coefficient of each channel;
according to the amplitude-phase correction coefficient of the target detection points at the distance average value of all the target detection points, the distance information in the target detection points is used for carrying out target detection processing on the original echo signal to obtain a detection result;
acquiring azimuth angle deviation and pitch angle deviation of a target detection point in the detection result;
judging whether the fitting slope of the phase correction coefficient is smaller than or equal to a preset threshold value, whether the azimuth angle deviation and the pitch angle deviation of each target detection point are consistent, judging whether the iteration times of the method enable the azimuth angle deviation to be converged within the range of the azimuth angle threshold value and enable the pitch angle deviation to be converged within the range of the pitch angle threshold value, and if one or more judgment results are negative, carrying out iteration processing according to the updated parameter duplication step; if the judgment results are yes, stopping the iterative processing of the step, and outputting a calibration parameter, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
Optionally, obtaining the distance deviation of the target detection point in each channel includes:
respectively drawing a distance-sampling time two-dimensional graph of the trace point according to respective distance coordinates and time coordinates of the target measurement trace point result and the target detection trace point result;
and when the point traces on the two-dimensional graph are superposed, determining the distance of the target detection point trace translated along the distance axis as the distance deviation of the target detection point.
Optionally, the step of performing correction processing on the amplitude-phase coefficient of the target detection point in each channel to obtain the result of the amplitude-phase correction coefficient and the fitting slope of the phase correction coefficient of each channel includes:
by the following formula:
Figure BDA0003658135900000161
Figure BDA0003658135900000162
Figure BDA0003658135900000163
Figure BDA0003658135900000171
correcting the amplitude-phase coefficient of the target detection point in each channel to obtain an amplitude-phase correction coefficient result;
wherein d is x For azimuthal antenna phase center spacing, d z To pitch towards the antenna phase center spacing,
Figure BDA0003658135900000172
n is the amplitude correction coefficient calculated for each target detection point in the kth iteration,
Figure BDA0003658135900000173
n is the phase calculated by each target detection point in the k iterationThe coefficient of the bit correction is set to be,
Figure BDA0003658135900000174
measuring azimuth angle theta for GPS in parameter information of each target detection point j The pitch angle is adopted, and lambda is a preset constant and represents the working wavelength of the radar;
all phase correction coefficient results obtained by calculation according to target detection points in each channel
Figure BDA0003658135900000175
Using the distance D in the parameter information of the target detection point j One-dimensional phase unwrapping and linear fitting are carried out on the independent variable to obtain a fitting slope
Figure BDA0003658135900000176
As the fitting slope of the acquired phase correction coefficient of each channel.
Optionally, the performing target detection processing on the original echo signal according to the amplitude-phase correction coefficient of the target detection point at the distance average of all the target detection points based on the distance information in the target detection points to obtain a detection result includes:
selecting distance information D in the parameter information of each target detection point j The point at the distance average value is a selected target detection point;
amplitude and phase correction coefficient calculated by using parameter information of the selected target detection point
Figure BDA0003658135900000177
Figure BDA0003658135900000178
Target detection processing is carried out on the 4 paths of original echo data to obtain a detection result, wherein the detection result is parameter information of each target detection point after one iteration and comprises distance information D of the target detection points j Amplitude information of each channel
Figure BDA0003658135900000179
Phase information of each channel
Figure BDA00036581359000001710
And radar measurement azimuth angle obtained by 4-channel sum and difference beam measurement method
Figure BDA00036581359000001711
Measuring pitch angle with radar
Figure BDA00036581359000001712
Optionally, obtaining the azimuth angle deviation and the pitch angle deviation of the target detection point in the detection result includes:
measuring the azimuth angle of the radar of each target detection point in the detection result
Figure BDA00036581359000001718
And radar measurement of pitch angle
Figure BDA00036581359000001714
And the GPS measurement azimuth angle in the parameter information of the corresponding target detection point
Figure BDA00036581359000001715
And GPS measures pitch angle theta j Comparing and obtaining the azimuth angle deviation of each target detection point
Figure BDA00036581359000001716
Deviation from pitch angle
Figure BDA00036581359000001717
It should be noted that the apparatus is an apparatus corresponding to the above method, and all the implementations in the above method embodiment are applicable to the embodiment of the apparatus, and the same technical effects can be achieved.
The method and the device for acquiring the calibration parameters of the radar system can calibrate the low-altitude target detection radar arranged at the working position, and the calibration parameters acquired in a mode of multi-iteration processing are used for target detection processing by acquiring the target echo information of the cooperative unmanned aerial vehicle with the real-time GPS position, so that the precision of a target detection result is improved, and the accuracy of the low-altitude flight target detection result is ensured.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (10)

1. A method for obtaining calibration parameters of a radar system is characterized by comprising the following steps:
acquiring a target measurement point track result of a flight track of the unmanned aerial vehicle in the flight process;
obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle;
determining target detection points according to the target measurement trace results and the target detection trace results;
according to the target detection point, determining a calibration parameter of the radar, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
2. The method for obtaining calibration parameters of a radar system according to claim 1, wherein obtaining a target measurement point trace result of a flight trace of the unmanned aerial vehicle during flight comprises:
acquiring position information of each sampling point in a flight track of the unmanned aerial vehicle in the flight process;
and calculating the distance between each sampling point and the radar and the azimuth angle and the pitch angle of each sampling point relative to the normal direction of the radar antenna array surface according to the position information of the sampling points and the position information of the center of the radar antenna array surface to obtain the target measurement trace point result.
3. The method for obtaining the calibration parameters of the radar system according to claim 1, wherein obtaining a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the drone comprises:
acquiring 4 paths of echo signals reflected by the unmanned aerial vehicle and received by the radar, wherein 1 path of echo signal corresponds to 1 antenna array surface of the radar;
respectively using amplitude and phase correction coefficients for 4 paths of echo signals reflected by the unmanned aerial vehicle
Figure FDA0003658135890000011
Carrying out target detection processing to obtain 4 groups of target detection trace results;
the distance information D of the target detection points detected in the 4 groups of target detection point trace results j And amplitude information of each channel
Figure FDA0003658135890000012
And phase information
Figure FDA0003658135890000013
Detecting a trace result as the target;
wherein j is the serial number of the target detection points and takes the value of 1-N, and N is the number of the target detection points;
i is a channel number, i is 1, 2, 3 and 4, and represents the number of a 4-channel, and a superscript (0) represents the initial values of the amplitude-phase information and the amplitude-phase correction coefficient.
4. The method for obtaining calibration parameters of a radar system according to claim 1, wherein determining a target detection point based on the target measurement trace result and the target detection trace result comprises:
performing feature matching on the target measurement trace result and the target detection trace result through the flight trace of the unmanned aerial vehicle, and determining a plurality of matched target detection points; matched parameter information of each target detection pointComprises distance information D relayed by target detection points from target measurement trace results j Amplitude information of each channel
Figure FDA0003658135890000021
Phase information of each channel
Figure FDA0003658135890000022
And GPS measured azimuth by matching from corresponding target measured trace results
Figure FDA0003658135890000023
Measuring pitch angle theta with GPS j 。
5. The method of claim 1, wherein determining the calibration parameters of the radar based on the target detection points comprises:
obtaining the distance deviation of target detection points in each channel;
correcting the amplitude-phase coefficient of the target detection point in each channel to obtain an amplitude-phase correction coefficient result and a fitting slope of the phase correction coefficient of each channel;
according to the amplitude-phase correction coefficient of the target detection points at the distance average value of all the target detection points, the distance information in the target detection points is used for carrying out target detection processing on the original echo signal to obtain a detection result;
acquiring azimuth angle deviation and pitch angle deviation of a target detection point in the detection result;
judging whether the fitting slope of the phase correction coefficient is smaller than or equal to a preset threshold value, whether the azimuth angle deviation and the pitch angle deviation of each target detection point are consistent, judging whether the iteration times of the method enable the azimuth angle deviation to be converged within the range of the azimuth angle threshold value and enable the pitch angle deviation to be converged within the range of the pitch angle threshold value, and if one or more judgment results are negative, carrying out iteration processing according to the updated parameter duplication step; if the judgment results are yes, stopping the iterative processing of the step, and outputting a calibration parameter, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
6. The method for obtaining calibration parameters of a radar system according to claim 5, wherein obtaining the distance deviation of the target detection point in each channel comprises:
respectively drawing a distance-sampling time two-dimensional graph of the trace point according to respective distance coordinates and time coordinates of the target measurement trace point result and the target detection trace point result;
and when the point traces on the two-dimensional graph are superposed, determining the distance of the target detection point trace translated along the distance axis as the distance deviation of the target detection point.
7. The method for obtaining calibration parameters of a radar system according to claim 5, wherein the step of performing correction processing on the amplitude-phase coefficient of the target detection point in each channel to obtain the result of the amplitude-phase correction coefficient and the fitting slope of the phase correction coefficient of each channel comprises:
by the following formula:
Figure FDA0003658135890000031
Figure FDA0003658135890000032
Figure FDA0003658135890000033
Figure FDA0003658135890000034
correcting the amplitude and phase coefficient of the target detection point in each channel to obtain the amplitude and phase correction coefficientThe result is;
wherein d is x For azimuthal antenna phase center spacing, d z To pitch towards the antenna phase center spacing,
Figure FDA0003658135890000035
the amplitude correction coefficients calculated for each target detection point in the kth iteration,
Figure FDA0003658135890000036
the phase correction coefficients calculated for each target detection point in the kth iteration,
Figure FDA0003658135890000037
measuring azimuth angle theta for GPS in parameter information of each target detection point j Measuring a pitch angle for the GPS in the parameter information of each target detection point, wherein lambda is a preset constant and represents the working wavelength of the radar;
all phase correction coefficient results obtained by calculation according to target detection points in each channel
Figure FDA0003658135890000038
Using the distance D in the parameter information of the target detection point j Performing one-dimensional phase unwrapping and linear fitting on the independent variable to obtain a fitting slope
Figure FDA0003658135890000039
As the fitting slope of the acquired phase correction coefficient of each channel.
8. The method for obtaining calibration parameters of a radar system according to claim 5, wherein the step of performing target detection processing on the original echo signal according to the amplitude-phase correction coefficient of the target detection point where the distance information in the target detection points is the average value of the distances between all the target detection points to obtain a detection result comprises:
selecting distance information D in the parameter information of each target detection point j For points at the distance average as selected targetMeasuring points;
using the amplitude-phase correction coefficient calculated by the parameter information of the selected target detection point
Figure FDA00036581358900000310
Figure FDA00036581358900000311
Carrying out target detection processing on 4 paths of original echo data to obtain a detection result, wherein the detection result is parameter information of each target detection point after one iteration and comprises distance information D of the target detection points j Amplitude information of each channel
Figure FDA00036581358900000312
Phase information of each channel
Figure FDA00036581358900000313
And radar measurement azimuth angle obtained by 4-channel sum and difference beam measurement method
Figure FDA00036581358900000314
Measuring pitch angle with radar
Figure FDA00036581358900000315
9. The method for obtaining calibration parameters of a radar system according to claim 5, wherein obtaining the azimuth angle deviation and the pitch angle deviation of the target detection point in the detection result comprises:
measuring the azimuth angle of the radar of each target detection point in the detection result
Figure FDA0003658135890000041
And radar measurement of pitch angle
Figure FDA0003658135890000042
To the corresponding purposeGPS measurement azimuth angle in mark detection point parameter information
Figure FDA0003658135890000043
And GPS measures pitch angle θ j Comparing and obtaining the azimuth angle deviation of each target detection point
Figure FDA0003658135890000044
Deviation from pitch angle
Figure FDA0003658135890000045
10. An apparatus for obtaining calibration parameters of a radar system, comprising:
the first acquisition module is used for acquiring a target measurement point track result of a flight track of the unmanned aerial vehicle in the flight process;
the second acquisition module is used for acquiring a target detection trace result obtained by the radar performing target detection processing according to the echo signal reflected by the unmanned aerial vehicle;
the processing module is used for determining target detection points according to the target measurement trace results and the target detection trace results; and acquiring a calibration parameter of each target detection point, wherein the calibration parameter comprises: amplitude and phase correction coefficients, azimuth angle deviation, pitch angle deviation and distance deviation.
CN202210568527.9A 2022-05-23 2022-05-23 Method and device for acquiring calibration parameters of radar system Pending CN114966579A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116203519A (en) * 2023-05-05 2023-06-02 中国电子科技集团公司信息科学研究院 Error calibration method for distributed radar system transceiver channel distance system
CN116299401A (en) * 2023-05-19 2023-06-23 成都航空职业技术学院 Constant false alarm method and device based on target scattering point position and storage medium thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116203519A (en) * 2023-05-05 2023-06-02 中国电子科技集团公司信息科学研究院 Error calibration method for distributed radar system transceiver channel distance system
CN116203519B (en) * 2023-05-05 2023-06-27 中国电子科技集团公司信息科学研究院 Error calibration method for distributed radar system transceiver channel distance system
CN116299401A (en) * 2023-05-19 2023-06-23 成都航空职业技术学院 Constant false alarm method and device based on target scattering point position and storage medium thereof
CN116299401B (en) * 2023-05-19 2023-10-17 成都航空职业技术学院 Constant false alarm method and device based on target scattering point position and storage medium thereof

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