A radar target calibration method for vehicle-mounted platforms

Abstract

This invention relates to a radar calibration method for a vehicle-mounted platform. Through cold calibration, the platform's inertial navigation information is acquired to calibrate the error between the radar antenna mounting plane and the vehicle-mounted platform's reference plane. Through hot calibration, the horn radiation signal placed in the far field in front of the radar antenna is received to calibrate the error between the radar's electrical axes (azimuth and elevation) and the vehicle-mounted platform's reference plane. Through mathematical calculations based on the radar's mounting relationship on the platform, the radar antenna coordinate system is transformed into the carrier coordinate system, eliminating the influence of factors such as the translation of the radar axis zero point, the rotation of the radar axis zero point, the translation of the tilting axis zero point, and the rotation of the turntable axis. This completes the calibration process, maximizing the radar's detection accuracy on the vehicle-mounted platform and solving the problems of data registration and data fusion between radar and different platforms and sensors in specific application scenarios.

Description

Technical Field

[0001] This invention belongs to the field of radar calibration technology and relates to a radar target calibration method for a vehicle-mounted platform. Background Technology

[0002] As the primary reconnaissance and perception sensor for vehicle-mounted platforms, radar boasts advantages such as all-weather, 24 / 7 operation. The measurement accuracy of radar directly impacts the combat effectiveness of the vehicle-mounted platform. Radar measurement errors are related to numerous factors, including the target, atmospheric propagation, and the radar itself. In terms of error nature, radar measurement errors include random errors and systematic errors. Random errors require mitigation during radar design and manufacturing, taking appropriate measures based on influencing factors, such as improving the radar's ranging and angle measurement accuracy. Systematic errors need to be eliminated after radar manufacturing and installation, such as errors between the radar's mechanical and electrical axes, and errors between the radar's electrical axis and the platform's axial direction. Radar calibration aims to calibrate and eliminate systematic errors caused by factors such as the radar's installation position and method on the vehicle-mounted platform, thereby improving the measurement accuracy of the vehicle-mounted platform's radar system. Therefore, radar calibration is an essential preparatory step after radar installation and before test runs.

[0003] The basic principle of radar target calibration is as follows: For a given radar target, a sample of measured values ​​{Vi} is obtained from the radar being calibrated. Then, a sample of true values ​​{Qi} is determined using higher-precision measuring equipment. The statistical average of these data samples is obtained using mathematical statistics. The statistical average of the samples can be approximated by the expected value of the statistical object, i.e., the final calibration result—the difference between the measured value and the true value—is the systematic error. This error is corrected by software to adjust the radar measurements. Summary of the Invention

[0004] Technical problems to be solved

[0005] Radar calibration aims to correct and eliminate systematic errors caused by factors such as the radar's installation location and method on the vehicle platform, thereby improving the radar measurement accuracy on the platform. To overcome the shortcomings of existing technologies, this invention provides a vehicle-mounted platform radar calibration method. Through vehicle-mounted platform radar calibration, the radar measurement accuracy on the platform is improved, meeting the needs of radar in specific application scenarios (data registration and fusion between the radar and different platforms and sensors under close-range detection conditions).

[0006] Technical solution

[0007] A radar calibration method for a vehicle-mounted platform, characterized by including: error calibration between the radar mounting plane and the platform reference plane, error calibration between the radar electric axis and the platform reference plane, and transformation from the radar antenna coordinate system to the carrier coordinate system;

[0008] The aforementioned radar mounting plane and platform reference plane error calibration includes the following steps:

[0009] Step 1a: Preparation before measurement. Place the level on the radar mounting surface of the vehicle platform. At the same time, power on the inertial navigation system in the cabin. The inertial navigation system enters the calibration state. After calibration, set the inertial navigation system to the high-precision attitude data output state.

[0010] Step 1b: True value measurement. Using a level, measure the angle in the X direction, where X is the direction of the vehicle's front and rear lines. Measure the X direction angle n times and calculate the average value.

[0011] Step 1c: True value measurement. Using a level, measure the angle in the Y direction, where Y is orthogonal to X. Measure the Y-direction angle n times and calculate the average.

[0012] Step 1d: Observe the inertial navigation output data, record n ​​pitch angle values, and calculate the average value:

[0013] Step 1e: Observe the inertial navigation output data, record the roll and pitch values ​​n times, and calculate the average value:

[0014] Step 1f: Calculate the systematic error and record the test data:

[0015] Pitch error:

[0016] Roll error:

[0017] The aforementioned radar electric axis and platform reference plane error calibration includes the following steps:

[0018] Step 2a: Select a flat and open field, place the vehicle body on one side of the field, and level the vehicle body; place the target plate 1000 meters away from the vehicle body. At the same time, power on the inertial navigation system in the vehicle cabin, and the inertial navigation system enters the calibration state. After the calibration is completed, set the inertial navigation system to the high-precision attitude data output state.

[0019] Step 2b: Use differential GPS to locate the radar position and the target position respectively, and obtain the longitude, latitude, and altitude information of the radar position and the longitude, latitude, and altitude information of the target position.

[0020] Step 2c: Place a simple signal source on the target plate, turn on the power, enter the radar target calibration mode, read the azimuth angle of the radiation source relative to the radar through the display interface, record n ​​sets of angle values ​​and calculate the average. The elevation angle of the radiation source relative to the radar is read from the display interface, n sets of elevation angle values ​​are recorded and the average is calculated.

[0021] Step 2d: Based on GPS data and vehicle inertial navigation information, calculate the distance and azimuth angle of the target plate signal source position relative to the radar. and pitch angle

[0022] Step 2e: Calculate the systematic error and record the test data;

[0023] Azimuth error:

[0024] Pitch error:

[0025] The transformation from the radar antenna coordinate system to the carrier coordinate system includes the following steps:

[0026] Step 3a: The antenna is installed and translated on the "folding device," and the translation is relative to the zero-position origin of the folding axis by the corresponding "structural position amount."

[0027]

[0028]

[0029] Among them, z daofu : is the translation of the radar axis zero point; R E : The slant distance from the target to the origin of the zero-position coordinate system of the normal, a E : Azimuth angle of the radar normal null antenna coordinate system, e E : Elevation angle of the radar normal null antenna coordinate system;

[0030] Step 3b: The device is installed and rotated "on the collapsing device," rotating by the corresponding "structural rotation amount" relative to the zero-position axis of the collapsing shaft.

[0031]

[0032] Among them, e daofu : This is the amount of rotation at the zero point of the radar shaft;

[0033] Step 3c: The "collapse device" is installed and moved on the "multi-functional turntable," and the "structural translation amount" is shifted relative to the zero-position origin of the turntable's axis.

[0034]

[0035] Where, x zhuan : This is the amount of translation at the zero point of the tilting shaft;

[0036] Step 3d: The structure is installed and rotated on the "multi-functional turntable," rotating by the corresponding "structural rotation amount" relative to the turntable's axis.

[0037]

[0038] Among them, a zhuan : This is the amount of rotation of the turntable's axis;

[0039] Step 3e: The "multi-functional turntable" is installed and translated on the "gun turret," and its translation relative to the inertial navigation origin within the gun turret is by a corresponding "structural offset."

[0040]

[0041] Where, x INS y INS z INS : Coordinates relative to the inertial navigation origin;

[0042] Step 3f: The influence of turret attitude on coordinates is characterized using inertial navigation data.

[0043] Define the rotation matrices when three rotation amounts are applied independently: heading transformation, pitch transformation, and roll transformation.

[0044] North by east is positive

[0045] Head up is the best position

[0046] Pressing to the right is correct.

[0047] When the data processing unit needs to perform a "coordinate transformation" on the obtained target information, a positive transformation should be applied, M. fwd =M a ·M p ·M r

[0048] Its effect manifests as a sequential combination of the three rotational transformations, as follows:

[0049]

[0050] A further technical solution of the present invention: n is 5 in steps 1b, 1c, 1d, and 1e.

[0051] A further technical solution of the present invention: n is 5 in step 2c.

[0052] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0053] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0054] Beneficial effects

[0055] This invention provides a radar calibration method for a vehicle-mounted platform. Through cold calibration, it acquires the platform's inertial navigation information to calibrate the error between the radar antenna mounting plane and the vehicle-mounted platform's reference plane. Through hot calibration, it receives the horn radiation signal placed in the far field in front of the radar antenna to calibrate the error between the radar's electrical axes (azimuth and elevation) and the vehicle-mounted platform's reference plane. Through mathematical calculations based on the radar's mounting relationship on the platform, it completes the transformation from the radar antenna coordinate system to the carrier coordinate system, eliminating the influence of factors such as the translation of the radar axis zero point, the rotation of the radar axis zero point, the translation of the tilting axis zero point, and the rotation of the turntable axis. This completes the calibration process, maximizing the radar's detection accuracy on the vehicle-mounted platform and solving the problems of data registration and data fusion between radar and different platforms and sensors in specific application scenarios.

[0056] There are no examples of radar installation and application for this vehicle-mounted platform. The purpose of this invention is to establish a standardized process for radar calibration of this vehicle-mounted platform, providing important support for subsequent equipment testing, manufacturing, and deployment. Attached Figure Description

[0057] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0058] Figure 1 This is a schematic diagram illustrating the error calibration between the radar mounting plane and the platform reference plane using the method of the present invention.

[0059] Figure 2 This is a schematic diagram illustrating the error calibration between the radar electric axis (azimuth and elevation) and the platform reference plane using the method of the present invention.

[0060] Figure 3 This is a schematic diagram illustrating the target calibration error correction method of the present invention. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0062] The vehicle-mounted platform radar calibration method involved in this invention not only needs to improve the measurement accuracy of the radar on the platform, but also needs to solve the problems of data registration and data fusion between the radar and different platforms and different sensors under specific application conditions. Especially in close-range detection, the influence of factors such as the translation of the radar axis zero point, the rotation of the radar axis zero point, the translation of the tilting axis zero point, and the rotation of the turntable axis on the coordinate translation transformation becomes significant. Therefore, the specific technical problems to be solved by the vehicle-mounted platform radar calibration method of this invention include:

[0063] 1) Error calibration between the antenna mounting plane and the vehicle platform reference plane;

[0064] 2) Error calibration of radar electric axes (azimuth and pitch) and vehicle platform reference plane;

[0065] 3) Transformation from radar antenna coordinate system to carrier coordinate system.

[0066] The first two steps are general radar calibration procedures, which are generally required to eliminate systematic errors caused by the radar being installed on the platform. They can meet the calibration application needs when the radar installation position relationship on the platform is relatively simple and typical. The third step is a calibration procedure specific to this radar, which can adapt to the special installation method of this radar on the platform and meet the data registration and fusion problems between the radar and different platforms and different sensors, thereby meeting the calibration application needs of this radar.

[0067] The vehicle-mounted platform contains three reference planes: the carrier, the navigation system, and the radar antenna mount, each corresponding to one of three coordinate systems: the carrier coordinate system, the inertial (geographic) coordinate system, and the radar antenna coordinate system. The relative relationship between the carrier coordinate system (X, Y, Z) and the inertial coordinate system (N, E, D) is described by a transformation matrix consisting of three Krylov angles W (heading angle), H (roll angle), and U (pitch angle). The relative relationship between the radar antenna coordinate system (r, e, d) and the carrier coordinate system is represented by a transformation matrix consisting of two Euler angles E (antenna pitch angle) and G (antenna azimuth angle). Direct radar measurement data is based on the antenna coordinate system, while the carrier system ultimately requires data relative to the geographic coordinate system after coordinate transformation, necessitating corresponding coordinate transformations. While radar generally ignores small-scale translational and rotational transformations during long-range detection, these transformations become indispensable for accurate coordination between different platforms and sensors during short-range detection. This invention effectively solves these problems.

[0068] After the radar is installed on the vehicle platform, system errors are caused by factors such as the inconsistency between the installation plane and the platform reference plane, and the inconsistency between the radar system's electrical axis and the platform reference plane. This invention uses a cold calibration method to compare and calibrate the acquired platform inertial navigation information with the axial data measured by the radar installation plane level instrument, correcting the system errors caused by the inconsistency between the installation plane and the platform reference plane. A hot calibration method is used to receive the horn radiation signal placed in the far field in front of the radar antenna, comparing and calibrating the theoretically calculated target position with the actual radar measurement results, correcting the system errors caused by the inconsistency between the radar system's electrical axis and the platform reference plane. Finally, considering the installation position relationship of the radar on the platform, the transformation from the radar antenna coordinate system to the carrier coordinate system and the radar calibration work are completed, achieving data registration between the radar and the platform sensors.

[0069] The specific steps for radar target calibration are as follows:

[0070] (I) Calibration of the error between the radar mounting plane and the platform reference plane

[0071] During radar calibration, it is essential to confirm that the heading angle W, roll angle H, and pitch angle U output by the inertial navigation system on the vehicle platform are completely consistent with the platform's actual attitude, or that any fixed deviations between them have been calibrated and eliminated. Similarly, the radar antenna mounting plane must also be aligned with the vehicle platform's reference plane. This is the foundation and prerequisite for accurate radar calibration, and an integral part of the calibration process; only radar calibration data obtained on this basis are truly valid.

[0072] The calibration steps for the error between the radar mounting plane and the platform reference plane are as follows:

[0073] 1) Before measurement, the level instrument is placed on the radar mounting surface of the vehicle platform. At the same time, the inertial navigation system in the cabin is powered on and enters the calibration state. After calibration, the inertial navigation system is set to the high-precision attitude data output state.

[0074] 2) True value measurement: Using a level, measure the angle in the X direction, where X is the direction of the vehicle's front and rear lines. Measure the X direction angle 5 times to obtain the X direction angle value P. i Let i = 1, 2, ... 5, and calculate the mean:

[0075] 3) True value measurement: Using a level, measure the angle in the Y direction. Y is orthogonal to X. Measure the Y direction angle 5 times to obtain the Y direction angle as R. i Let i = 1, 2, ... 5, and calculate the mean:

[0076] 4) Observe the inertial navigation system output data and record 5 pitch angle values: P / i, i = 1, 2, ... 5, and calculate the mean:

[0077] 5) Observe the inertial navigation output data and record the roll and pitch values ​​5 times: R / i, i = 1, 2, ... 5, and calculate the mean:

[0078] 6) Calculate the system error and record the test data.

[0079] Pitch error:

[0080] Roll error:

[0081] (II) Radar electrical axis (azimuth and elevation) and platform reference plane error calibration

[0082] The radar is mounted on the vehicle platform component through a positioning hole. The physical position cannot guarantee that the corresponding azimuth is perfectly positive and the pitch is consistent with the platform reference plane. Therefore, after the radar is installed, it is necessary to eliminate the relevant errors caused by the installation through target calibration. Specifically, this includes the error calibration of the radar azimuth electrical axis zero point and the platform reference plane, as well as the error calibration of the radar pitch electrical axis zero point and the platform reference plane.

[0083] The calibration steps for the radar electrical axis (azimuth and elevation) error with the platform reference plane are as follows:

[0084] 1) Select a flat and open site, place the vehicle body on one side of the site and level the vehicle body; place the target plate 1000 meters away from the vehicle body. At the same time, power up the inertial navigation system in the cabin and put the inertial navigation system into the calibration state. After the calibration is completed, set the inertial navigation system to the high-precision attitude data output state.

[0085] 2) Differential GPS is used to locate the radar position and the target plate position respectively, and the longitude, latitude, and altitude of the radar position and the longitude, latitude, and altitude of the target plate position are obtained.

[0086] 3) Place a simple signal source at the target plate, turn on the power, enter the radar target calibration mode, read the azimuth angle of the radiation source relative to the radar through the display interface, record 5 sets of angle values ​​A / i, i=1,2,…5, and calculate their average value. The elevation angle of the radiation source relative to the radar is read from the display interface. Five sets of elevation angle values ​​E / i, i = 1, 2, ... 5, are recorded, and their average value is calculated.

[0087] 4) Based on GPS data and vehicle inertial navigation information, calculate the distance and azimuth angle of the target plate signal source position relative to the radar. and pitch angle

[0088] 5) Calculate the system error and record the test data.

[0089] Azimuth error:

[0090] Pitch error:

[0091] (III) Transformation from Radar Antenna Coordinate System to Carrier Coordinate System

[0092] Based on the installation position of the radar on the platform, the transformation from the radar antenna coordinate system to the carrier coordinate system and the radar target calibration work are completed to achieve data registration between the radar and the platform sensors.

[0093] The normal zero coordinate system of this invention defines coordinates according to "azimuth" and "elevation".

[0094] The coordinates of a point directly detected by radar can be identified as follows:

[0095]

[0096] in,

[0097] R E The slant distance between the target and the origin of the zero-position coordinate system of the normal.

[0098] a E : Azimuth angle of the radar's zero-position antenna coordinate system. The orientation is consistent with the radar transmission, with rightward being positive.

[0099] e E : The elevation angle of the radar's null-position antenna coordinate system. The orientation is consistent with the radar transmission, with downward being positive (so that the minimum rotation amount is consistent with the "northeast" coordinate system).

[0100] Note: E represents the electronically scanned antenna, and the coordinate system is the zero-normal coordinate system.

[0101] The coordinate transformation process is as follows:

[0102] (1) The antenna is installed and translated on the "folding device", which translates the "structural position amount" relative to the zero-position origin of the folding axis.

[0103]

[0104] in,

[0105] z daofu This is the translation of the radar's rotation axis zero point. When the radar antenna plane is perpendicular to the horizontal (or the vehicle body), the upward translation is positive.

[0106] Note: To minimize the rotation and closely approximate the "northeast coordinates", a negative sign needs to be added before it.

[0107] (2) The rotation of the device on the "collapse device" corresponds to the "structural rotation amount" relative to the zero-position axis of the collapse shaft.

[0108]

[0109] in,

[0110] e daofu This refers to the rotation amount at the zero point of the radar shaft. When the radar antenna plane is perpendicular to the horizontal (or the vehicle body), upward rotation is positive, with zero rotation in the vertical state. Continuing to rotate upward will produce an upward elevation angle, currently typically 10 degrees. That is, the typical value e. daofu It is +10°.

[0111] (3) The "collapse device" is installed and moved on the "multi-functional turntable", and the "structural translation amount" is translated relative to the zero point of the turntable axis.

[0112]

[0113] in,

[0114] x zhuan This is the translation amount of the zero point of the tilting shaft. A positive translation occurs when the shaft is translated backward along the extension line of the turntable's zero position.

[0115] Note: To minimize the rotation and closely approximate the "northeast coordinates", a negative sign needs to be added before it.

[0116] (4) The structure rotates relative to the turntable axis by the amount of rotation installed on the "multi-functional turntable".

[0117]

[0118] in,

[0119] a zhuan This is the amount of rotation of the turntable's axis. Right-hand rotation is positive.

[0120] (5) The "multi-functional turntable" is installed and translated on the "gun turret", and the translation is relative to the inertial navigation origin within the gun turret by the corresponding "structural offset".

[0121]

[0122] in,

[0123] x INS : Relative to the inertial navigation origin, backward is positive. Here, to minimize rotation and closely approximate the "northeast-east coordinates", a negative sign needs to be added before it.

[0124] y INS : Relative to the origin of the inertial navigation system, to the right is positive.

[0125] z INS: Relative to the inertial navigation origin, upward is positive. Here, to minimize rotation and closely approximate the "northeast-east coordinates", a negative sign needs to be added before it.

[0126] (6) The influence of turret attitude on coordinates is characterized using inertial navigation data.

[0127] The following defines the rotation matrices for three independent rotation amounts: heading transformation, pitch transformation, and roll transformation.

[0128] North by east is positive

[0129] Head up is the best position

[0130] Pressing to the right is correct.

[0131] When the data processing unit needs to perform a "coordinate transformation" on the obtained target information, a positive transformation should be applied, M. fwd =M a ·M p ·M r

[0132] Its effect manifests as a sequential combination of the three rotational transformations. Specifically:

[0133]

[0134] In the above process, the roll and pitch errors obtained from the error calibration between the radar mounting plane and the platform reference plane are corrected in the inertial navigation data; the azimuth and pitch errors obtained from the error calibration between the radar electric axis (azimuth and pitch) and the platform reference plane are corrected in the target azimuth and pitch data reported by the radar signaling system; during the transformation from the radar antenna coordinate system to the carrier coordinate system, the influence of factors such as the translation of the radar axis zero point, the rotation of the radar axis zero point, the translation of the tilting axis zero point, and the rotation of the turntable axis are eliminated, thus completing the target calibration process and solving the problem of radar and platform sensor data fusion under specific application backgrounds.

[0135] To enable those skilled in the art to better understand the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0136] On a certain vehicle-mounted platform, the radar is mounted on a collapsing mechanism via a rotating shaft. Due to the special nature of the installation position and relationship, the transformation from the radar antenna coordinate system to the carrier coordinate system requires several coordinate rotation transformations and translations. The radar antenna coordinate system is translated and rotated to the reference zero position of the collapsing mechanism's rotating shaft. The reference zero position of the collapsing mechanism's rotating shaft is then translated and rotated to the reference zero position of the multi-functional turntable's rotating shaft. The reference zero position of the multi-functional turntable's rotating shaft is then translated and rotated to the reference zero position of the turret's internal reference surface. The inertial navigation data provided by the vehicle-mounted system is now used as the reference zero position of the turret's internal reference surface.

[0137] It should be noted that when conducting long-distance detection, small-scale translation transformations are generally ignored. However, for close-range detection, the aforementioned translation transformations become indispensable for accurate coordination between different platforms and sensors. This is a significant difference between the application of this invention and conventional methods.

[0138] The radar calibration process will be carried out in detail below:

[0139] (I) Calibration of the error between the radar mounting plane and the platform reference plane

[0140] 1) Place the level on the radar mounting surface, i.e. the chassis for the overturning mechanism. At the same time, power on the inertial navigation system in the cabin and confirm that the inertial navigation system has high-precision attitude data output according to the FlexRay inertial navigation interface data identifier.

[0141] 2) Using a level, measure the angle in the X direction, where X is the direction of the vehicle's front and rear lines. Measure the X direction angle five times to obtain the X direction angle value P. i Let i = 1, 2, ..., 5, with angles of 1.37°, 1.37°, 1.36°, 1.36°, and 1.37° respectively. Calculate the mean: It is 1.37°;

[0142] 3) Using a level, measure the angle in the Y direction. Y is orthogonal to X. Measure the angle in the Y direction 5 times to obtain the angle R. i Let i = 1, 2, ..., 5, with angles of 0.87°, 0.87°, 0.86°, 0.86°, and 0.87° respectively. Calculate the mean: It is 0.87°;

[0143] 4) Read the current high-precision inertial navigation data from the FlexRay inertial navigation interface and record 5 pitch angle values: P / i, i = 1, 2, ... 5, which are 1.21°, 1.22°, 1.21°, 1.21° and 1.22° respectively. Calculate the average value: It is 1.21°;

[0144] 5) Read the current high-precision inertial navigation data from the FlexRay inertial navigation interface and record 5 roll / pitch values: R / i, i = 1, 2, ... 5, which are 0.57°, 0.57°, 0.58°, 0.57° and 0.57° respectively. Calculate the average value: It is 0.57°;

[0145] 6) Calculate the system error and record the test data.

[0146] Pitch error:

[0147] Roll error:

[0148] The above system error correction values ​​are included in the inertial navigation data.

[0149] (II) Radar electrical axis (azimuth and elevation) and platform reference plane error calibration

[0150] 1) Park the vehicle in an open outdoor test area. Level the vehicle and place the target plate about 1000 meters away from the vehicle. At the same time, power on the inertial navigation system in the cabin and confirm that the inertial navigation system is outputting high-precision attitude data according to the FlexRay inertial navigation interface data.

[0151] 2) Differential GPS is used to locate the radar position and the target plate position respectively, and the longitude, latitude, and altitude of the radar position and the longitude, latitude, and altitude of the target plate position are obtained.

[0152] The radar GPS location information is: 34.03755 degrees north latitude, 108.61835 degrees east longitude, and 585 meters above sea level.

[0153] The target's GPS location information is: 34.04676 degrees north latitude, 108.61800 degrees east longitude, and 581 meters above sea level.

[0154] 3) Turn on the target plate signal source and enter the radar target calibration mode. Read the azimuth angle of the radiation source relative to the radar through the display interface, and record 5 sets of angle values ​​A / i, i = 1, 2, ... 5, which are 32.96°, 32.97°, 32.96°, 32.97° and 32.97° respectively, with an average azimuth angle of 32.97°; read the elevation angle of the radiation source relative to the radar through the display interface, and record 5 sets of elevation angle values ​​E / i, i = 1, 2, ... 5, which are -0.12°, -0.11°, -0.11°, -0.11° and -0.11° respectively, with an average elevation angle of -0.11°;

[0155] 4) The vehicle heading angle is read as 325.64°. Based on the GPS data and the vehicle's inertial navigation information, the distance, azimuth, and elevation angle of the target plate signal source relative to the radar are calculated.

[0156] Distance: 1023 meters;

[0157] Azimuth: 32.56 degrees;

[0158] Pitch angle: -0.21 degrees;

[0159] 5) Calculate the system error and record the test data.

[0160] Azimuth error: ΔA = -0.41°;

[0161] Pitch error: ΔE = -0.10°.

[0162] (III) Error Correction

[0163] Through the radar target calibration process described above, the following system error data were obtained:

[0164] Roll error: -0.16 degrees;

[0165] Pitch error: -0.30 degrees;

[0166] Azimuth error: -0.41 degrees;

[0167] Pitch error: -0.10 degrees;

[0168] The radar target detection data is as follows:

[0169] Distance: 1023 meters;

[0170] Azimuth: 32.56 degrees;

[0171] Pitch angle: -0.21 degrees;

[0172] By measuring the installation relationship between the radar and the vehicle body, the positional relationship data between the antenna coordinate system and the carrier coordinate system are obtained:

[0173] The antenna's translational displacement on the tilting mechanism is 0.02 meters.

[0174] The antenna's rotation on the tilting mechanism: 10 degrees;

[0175] The translational displacement of the tilting mechanism on the multi-functional turntable is 0.5 meters.

[0176] The tilting mechanism's rotation on the multi-functional turntable is 10 degrees.

[0177] The forward and backward translation of the multi-functional turntable on the turret inertial navigation mounting surface is 0.5 meters.

[0178] The left-right translation of the multi-functional turntable on the turret inertial navigation mounting surface is 0.5 meters.

[0179] The vertical translation of the multi-functional turntable on the turret inertial navigation mounting surface is 0.5 meters.

[0180] The platform provides the following turret heading angle information: 325.64 degrees;

[0181] The platform provides the following turret roll angle information: -0.28 degrees;

[0182] The platform provides the following turret pitch angle information: 1.37 degrees.

[0183] After correction of the target calibration system error:

[0184] Roll angle: -0.12 degrees;

[0185] Pitch angle: 1.67 degrees;

[0186] Target azimuth: 32.97 degrees;

[0187] Target pitch angle: -0.11 degrees;

[0188] The corrected position of the target in the carrier coordinate system is:

[0189] Target distance: 1023 meters;

[0190] Target azimuth: 9.25 degrees;

[0191] Target pitch angle: -9.8 degrees.

[0192] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A radar target calibration method for a vehicle-mounted platform, characterized in that... include: Calibration of errors between radar mounting plane and platform reference plane, calibration of errors between radar electric axis and platform reference plane, and transformation from radar antenna coordinate system to carrier coordinate system; The aforementioned radar mounting plane and platform reference plane error calibration includes the following steps: Step 1a: Preparation before measurement. Place the level on the radar mounting surface of the vehicle platform. At the same time, power on the inertial navigation system in the cabin. The inertial navigation system enters the calibration state. After calibration, set the inertial navigation system to the high-precision attitude data output state. Step 1b: True value measurement. Using a level, measure the angle in the X direction, where X is the direction of the vehicle's front and rear lines. Measure the X direction angle n times and calculate the average value. Step 1c: True value measurement. Using a level, measure the angle in the Y direction, where Y is orthogonal to X. Measure the Y-direction angle n times and calculate the average. Step 1d: Observe the inertial navigation output data, record n ​​pitch angle values, and calculate the average value: Step 1e: Observe the inertial navigation output data, record the roll and pitch values ​​n times, and calculate the average value: Step 1f: Calculate the systematic error and record the test data: Pitch error: Roll error: The aforementioned radar electric axis and platform reference plane error calibration includes the following steps: Step 2a: Select a flat and open field, place the vehicle body on one side of the field, and level the vehicle body; place the target plate 1000 meters away from the vehicle body. At the same time, power on the inertial navigation system in the vehicle cabin, and the inertial navigation system enters the calibration state. After the calibration is completed, set the inertial navigation system to the high-precision attitude data output state. Step 2b: Use differential GPS to locate the radar position and the target position respectively, and obtain the longitude, latitude, and altitude information of the radar position and the longitude, latitude, and altitude information of the target position. Step 2c: Place a simple signal source on the target plate, turn on the power, enter the radar target calibration mode, read the azimuth angle of the radiation source relative to the radar through the display interface, record n ​​sets of angle values ​​and calculate the average. The elevation angle of the radiation source relative to the radar is read from the display interface, n sets of elevation angle values ​​are recorded and the average is calculated. Step 2d: Based on GPS data and vehicle inertial navigation information, calculate the distance and azimuth angle of the target plate signal source position relative to the radar. and pitch angle Step 2e: Calculate the systematic error and record the test data; Azimuth error: Pitch error: The transformation from the radar antenna coordinate system to the carrier coordinate system includes the following steps: Step 3a: The antenna is installed and translated on the collapsing device, and the structural position is translated by the corresponding amount relative to the zero-position origin of the collapsing axis. Among them, z daofu : is the translation of the radar axis zero point; R E : The slant distance from the target to the origin of the zero-position coordinate system of the normal, a E : Azimuth angle of the radar normal null antenna coordinate system, e E : Elevation angle of the radar normal null antenna coordinate system; Step 3b: The tilting device is rotated relative to the zero-position axis of the tilting shaft by the corresponding structural rotation amount. Among them, e daofu : This is the amount of rotation at the zero point of the radar shaft; Step 3c: The collapsing device is installed and translated on the multi-functional turntable, and the structural translation is correspondingly shifted relative to the zero-position origin of the turntable axis. Where, x zhuan : This is the amount of translation at the zero point of the tilting shaft; Step 3d: The rotating component is mounted on the multi-functional turntable and rotates relative to the turntable axis by the corresponding structural rotation amount. Among them, a zhuan : This is the amount of rotation of the turntable's axis; Step 3e: The multi-functional turntable is installed and translated on the gun emplacement, and the translation is relative to the inertial navigation origin within the gun emplacement by the corresponding structural offset. Where, x INS y INS z INS : Coordinates relative to the inertial navigation origin; Step 3f: The influence of turret attitude on coordinates is characterized using inertial navigation data. Define the rotation matrices when three rotation amounts are applied independently: heading transformation, pitch transformation, and roll transformation. North by east is positive Head up is the best position Pressing to the right is correct. When the data processing unit needs to perform coordinate transformation on the obtained target information, a positive transformation should be applied, M. fwd =M a ·M p ·M r Its effect manifests as a sequential combination of the three rotational transformations, as follows:

2. The vehicle-mounted platform radar target calibration method according to claim 1, characterized in that: In steps 1b, 1c, 1d, and 1e, n is 5.

3. The vehicle-mounted platform radar target calibration method according to claim 1, characterized in that: In step 2c, n is 5.

4. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of claim 1.

5. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method of claim 1.

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