High-precision electric shaft and mechanical shaft calibration method based on combined measurement

Abstract

The invention provides a high-precision electric shaft and mechanical shaft calibration method based on combined measurement, which comprises the following steps of: accurately measuring the position of a target in a radar mechanical shaft coordinate system through various measurement means such as vision measurement and theodolite measurement in combination with common point conversion, and finally calibrating the position of the target according to the measurement result of the radar on the position of the target. And the angular deviation of the radar electric axis and the mechanical axis and the radar angle measurement error are calculated, so that high-precision radar angle measurement calibration and high-precision calibration of the deviation of the radar electric axis and the radar mechanical axis are realized.

Description

Technical Field

[0001] The present invention relates to the field of aerospace, and in particular to a high-precision electric axis and mechanical axis calibration method based on joint measurement, which can be applied to the technical field of radar electric axis and mechanical axis calibration. Background Art

[0002] At present, for space-borne machine-scanned radars, the radars are generally installed on the satellite platform to provide target measurement information for the satellite. Machine-scanned radars usually use a two-dimensional drive mechanism to drive the radar antenna to achieve search, tracking and measurement. Due to the installation errors of the radar antenna and the two-dimensional drive mechanism, there is an error between the mechanical axis of the two-dimensional drive mechanism movement and the electrical axis of the radar measurement. Therefore, for the application needs of radar system test calibration, it is necessary to calibrate the radar electrical axis and mechanical axis. However, the traditional electrical axis mechanical axis calibration method cannot meet the needs of high-precision angle measurement and electrical axis mechanical axis deviation calibration. Summary of the invention

[0003] The purpose of the present invention is to provide a high-precision electric axis mechanical axis calibration method based on joint measurement. Through visual measurement, theodolite measurement and other measurement means, combined with common point conversion, the position of the target in the radar mechanical axis coordinate system is accurately measured. Finally, according to the measurement result of the radar on the target position, the angular deviation of the radar electric axis and the mechanical axis and the radar angle measurement error are calculated, so as to realize the high-precision angle measurement calibration of the radar and the high-precision calibration of the deviation between the radar electric axis and the radar mechanical axis.

[0004] In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

[0005] A high-precision electric axis and mechanical axis calibration method based on joint measurement, comprising:

[0006] An electric axis and mechanical axis calibration system is built in a microwave darkroom. The horn antenna simulating the target is installed on a two-dimensional scanning frame, a cross target is attached in front of the horn antenna, and the center position of the cross target coincides with the normal line of the horn antenna. The radar antenna mechanism is installed on a T-shaped fixture, and the cubic prism is installed on the base of the radar antenna mechanism.

[0007] Place the radar antenna mechanism and the T-shaped fixture assembly horizontally, with the radar antenna normal facing upwards, stick the target point on the side of the T-shaped fixture, and use two theodolites to measure the position of the target point in the cubic prism coordinate system;

[0008] Place the radar antenna mechanism and the T-type fixture assembly vertically in front of the two-dimensional scanning frame, with the normal of the radar antenna facing the two-dimensional scanning frame. Paste the target points at the edge of the radar antenna and on the back of the T-type fixture. Control the radar antenna mechanism to rotate the azimuth axis and the pitch axis. Use a single-camera measurement system to obtain the position of the target points on the side and back of the T-type fixture in the radar mechanical axis coordinate system.

[0009] The target point coordinates on the back of the T-type fixture are taken as the common point to deduce the conversion relationship between the radar mechanical axis coordinate system and the prism coordinate system;

[0010] The horn antenna radiates the target echo signal, the radar receives the target echo signal and controls the mechanism to track the horn, and at the same time outputs the elevation angle and azimuth angle of the horn antenna in the radar mechanical axis coordinate system, controls the two-dimensional scanning frame to move the horn antenna to different positions, uses two theodolites to measure the positions of the horn antenna and the target point on the back of the radar antenna in the theodolite measurement coordinate system, and records the measured values ​​of the elevation angle and azimuth angle in the radar mechanical axis coordinate system;

[0011] The coordinates of the target point on the back of the T-type tooling are taken as the common point, and the position of the horn antenna in the theodolite measurement coordinate system is transferred to the position of the radar mechanical axis coordinate system. Then, according to the geometric relationship, it is mapped to the pitch and elevation angles of the mechanism to obtain the calibration value. The errors between the radar pitch and azimuth measurement values ​​and the calibration values ​​are calculated. The error mean is the error of the electric axis deviating from the radar mechanical axis, and the error variance is the radar angle measurement accuracy.

[0012] Optionally, the two-dimensional scanning frame moves to drive the horn antenna to move in horizontal and vertical directions.

[0013] Optionally, the cubic prism coordinate system is established as follows:

[0014] Set up two theodolites that have been aligned with each other, align the reference ruler, add scale information to the theodolite measurement system, and establish the theodolite measurement system;

[0015] In the theodolite measurement system, two theodolites are used to align the cubic prism, determine the position relationship between the cubic prism coordinate system and the two theodolites, use the two theodolites to measure the prism crosshairs, determine the origin of the prism coordinate system, and establish the prism coordinate system in the theodolite measurement system.

[0016] Optionally, a single-camera measurement system is used to obtain the positions of the target points on the side and back of the T-type fixture in the radar mechanical axis coordinate system, including:

[0017] Use a single-camera measurement system to monitor the position of the target point movement at the edge of the antenna, as well as the position of the target points on the side and back of the T-type fixture;

[0018] Two circles are fitted respectively using the moving position of the target point at the edge of the antenna. The straight line passing through the center of the circle and perpendicular to the circular plane is the radar mechanical axis. The intersection of the two straight lines is the origin of the radar mechanical axis coordinate system. The positions of the target points on the side and back of the T-type tooling in the radar mechanical axis coordinate system are obtained.

[0019] Optionally, the coordinates of the target point on the back of the T-shaped tooling are taken as the common point to deduce the geometric relationship between the radar mechanical axis coordinate system and the prism coordinate system, specifically including:

[0020] Select more than three common points that have both the radar mechanical axis coordinate system and the prism coordinate system, list the error equation of each common point, calculate the conversion parameters between the radar mechanical axis coordinate system and the prism coordinate system by the least squares principle, eliminate the common points with large errors according to the errors between the converted coordinate positions and the measured coordinate positions, and calculate the conversion parameters between the radar mechanical axis coordinate system and the prism coordinate system by the least squares principle for the remaining common points.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] The high-precision electric axis mechanical axis calibration method based on joint measurement of the present invention realizes the high-precision angle measurement calibration of the radar and the high-precision calibration of the electric axis deviation from the radar mechanical axis error, and also obtains the conversion relationship between the radar mechanical axis coordinate system and the prism coordinate system. It has the advantages of high measurement accuracy and comprehensive coverage of measurement results, and provides accurate and comprehensive data for system compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the description. Obviously, the drawings described below are an embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0024] Figure 1 It is a flow chart of a high-precision electric axis and mechanical axis calibration method based on joint measurement;

[0025] Figure 2 This is the block diagram of the electric axis and mechanical axis calibration system under microwave darkroom conditions;

[0026] Figure 3 This is a schematic diagram of target point measurement in the prism coordinate system;

[0027] Figure 4 This is a schematic diagram of target point measurement in the radar mechanical axis coordinate system;

[0028] Figure 5 Schematic diagram of high-precision calibration of the horn antenna position for simulating radar targets;

[0029] Figure 6 Schematic diagram of converting the radar mechanical axis coordinate system into the angle measurement coordinate system. DETAILED DESCRIPTION

[0030] The scheme proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the implementation method of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the accompanying drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0031] The present invention provides a high-precision electric axis and mechanical axis calibration method based on joint measurement, such as Figure 1 As shown, the specific implementation is as follows:

[0032] Step S1, build an electric axis and mechanical axis calibration system in a microwave darkroom, such as Figure 2 As shown, specifically, it includes: a horn antenna simulating a target is installed on a two-dimensional scanning frame in a microwave darkroom, the movement of the two-dimensional scanning frame drives the horn antenna to move in the horizontal and vertical directions, a cross target is pasted in front of the horn antenna, so that the center position of the cross target coincides with the normal line of the horn antenna; a radar antenna mechanism is installed on a T-shaped fixture, and a cubic prism is installed on the base of the radar antenna mechanism, ensuring that the two surfaces of the cubic prism are not blocked by the radar antenna mechanism;

[0033] Step S2, measuring the target point in the prism coordinate system, such as Figure 3 As shown, it specifically includes: setting up two theodolites that have been aimed at each other, aiming at the reference ruler, adding scale information to the theodolite measurement system, and establishing the theodolite measurement system. In the theodolite measurement system, two theodolites are used to align the cubic prism, determine the position relationship between the prism coordinate system and the two theodolites, use two theodolites to measure the prism crosshairs, determine the origin of the prism coordinate system, and establish the prism coordinate system in the theodolite measurement system. Place the assembly of the radar antenna mechanism and the T-type tooling horizontally, with the normal of the radar antenna facing upward, stick the target point on the side of the T-type tooling, and use the theodolite to measure the position of the target point in the cubic prism coordinate system.

[0034] Step S3, measuring the target point of the radar mechanical axis coordinate system, such as Figure 4As shown, it specifically includes: placing the assembly of the radar antenna mechanism and the T-type fixture vertically in front of the two-dimensional scanning frame, with the antenna normal facing the two-dimensional scanning frame, pasting two target points at the edge of the antenna, pasting multiple target points on the back of the T-type fixture, controlling the radar antenna mechanism to rotate the azimuth axis and the pitch axis, and using a single-camera measurement system to obtain the position of the target points on the side and back of the T-type fixture in the radar mechanical axis coordinate system. Specifically, a single-camera measurement system is used to monitor the position of the target point movement at the edge of the antenna, as well as the position of the target points on the side and back of the T-type fixture. Two circles are fitted using the position of the target point movement at the edge of the antenna, and the straight line passing through the center of the circle and perpendicular to the circular plane is the radar mechanical axis. The intersection of the two straight lines is the origin of the radar mechanical axis coordinate system, and the position of the target points on the side and back of the T-type fixture in the radar mechanical axis coordinate system is obtained.

[0035] Step S4, converting the radar mechanical axis coordinate system and the prism coordinate system based on the common point, specifically includes: taking the target point coordinates on the back of the T-type tooling as the common point, and calculating the conversion relationship between the radar mechanical axis coordinate system and the prism coordinate system. Specifically, select more than three common points that have both the radar mechanical axis coordinate system and the prism coordinate system, list the error equation of each common point, calculate the conversion parameters of the radar mechanical axis coordinate system and the prism coordinate system by the least squares principle, eliminate the common points with large errors according to the errors between the converted coordinate position and the measured coordinate position, and calculate the conversion parameters of the radar mechanical axis coordinate system and the prism coordinate system by the least squares principle for the remaining common points.

[0036] Step S5, high-precision calibration of the horn antenna position of the simulated radar target is performed, specifically including: the horn antenna is connected to a signal simulation source to radiate a target echo signal, the radar receives the echo signal and controls the mechanism to track the horn antenna, and simultaneously outputs the elevation angle and azimuth angle of the horn antenna in the radar mechanical axis coordinate system; two theodolites are set up near the radar, and a theodolite measurement system is established by mutual aiming and benchmark aiming; Figure 5 As shown, the two-dimensional scanning frame is controlled to move the horn antenna to different positions, and two theodolites are used to measure the positions of the horn antenna and the target point on the back of the antenna in the theodolite measurement coordinate system, and the radar measurement values ​​of the elevation angle and azimuth angle of the horn antenna at different positions are recorded.

[0037] Step S6, conduct high-precision calibration of radar electric axis mechanical axis deviation and angle measurement, specifically including: taking the target point coordinates on the back of the T-type fixture as the common point, transferring the position of the horn antenna in the theodolite measurement coordinate system to the position of the radar mechanical axis coordinate system, and then mapping to the pitch angle and elevation angle of the mechanism according to the geometric relationship to obtain the calibration value, calculating the error between the radar pitch angle and azimuth measurement value and the calibration value, the error mean is the error of the electric axis deviating from the radar mechanical axis, and the error variance is the radar angle measurement accuracy. Figure 6As shown in the figure, the target point coordinates on the back of the T-type tooling are taken as the common point. After the position of the horn antenna in the theodolite measurement coordinate system is transferred to the position of the radar mechanical axis coordinate system, each point of the horn point is connected with the origin of the radar mechanical axis coordinate system. The angle between the straight line and the YOX plane of the radar mechanical axis coordinate system is analyzed as the pitch angle calibration value. The angle between each straight line and the ZOX plane of the radar mechanical axis coordinate system is analyzed as the azimuth calibration value. The errors between the radar pitch angle and azimuth measurement values ​​and the calibration values ​​are calculated. The error mean is the error of the electric axis deviating from the radar mechanical axis, and the error variance is the radar angle measurement accuracy.

[0038] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0039] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A high-precision electric axis and mechanical axis calibration method based on joint measurement, characterized in that: include: An electric axis and mechanical axis calibration system is built in a microwave darkroom. The horn antenna simulating the target is installed on a two-dimensional scanning frame, a cross target is attached in front of the horn antenna, and the center position of the cross target coincides with the normal line of the horn antenna. The radar antenna mechanism is installed on a T-shaped fixture, and the cubic prism is installed on the base of the radar antenna mechanism. Place the radar antenna mechanism and the T-shaped fixture assembly horizontally, with the radar antenna normal facing upwards, stick the target point on the side of the T-shaped fixture, and use two theodolites to measure the position of the target point in the cubic prism coordinate system; Place the radar antenna mechanism and the T-type fixture assembly vertically in front of the two-dimensional scanning frame, with the normal of the radar antenna facing the two-dimensional scanning frame. Paste the target points at the edge of the radar antenna and on the back of the T-type fixture. Control the radar antenna mechanism to rotate the azimuth axis and the pitch axis. Use a single-camera measurement system to obtain the position of the target points on the side and back of the T-type fixture in the radar mechanical axis coordinate system. The target point coordinates on the back of the T-type fixture are taken as the common point to deduce the conversion relationship between the radar mechanical axis coordinate system and the prism coordinate system; The horn antenna radiates the target echo signal, the radar receives the target echo signal and controls the mechanism to track the horn, and at the same time outputs the elevation angle and azimuth angle of the horn antenna in the radar mechanical axis coordinate system, controls the two-dimensional scanning frame to move the horn antenna to different positions, uses two theodolites to measure the positions of the horn antenna and the target point on the back of the radar antenna in the theodolite measurement coordinate system, and records the measured values ​​of the elevation angle and azimuth angle in the radar mechanical axis coordinate system; The coordinates of the target point on the back of the T-type tooling are taken as the common point, and the position of the horn antenna in the theodolite measurement coordinate system is transferred to the position of the radar mechanical axis coordinate system. Then, according to the geometric relationship, it is mapped to the pitch and elevation angles of the mechanism to obtain the calibration value. The errors between the radar pitch and azimuth measurement values ​​and the calibration values ​​are calculated. The error mean is the error of the electric axis deviating from the radar mechanical axis, and the error variance is the radar angle measurement accuracy.

2. The high-precision electric axis and mechanical axis calibration method based on joint measurement according to claim 1, characterized in that: The movement of the two-dimensional scanning frame drives the horn antenna to move in the horizontal and vertical directions.

3. The high-precision electric axis and mechanical axis calibration method based on joint measurement according to claim 1, characterized in that: The cubic prism coordinate system is established as follows: Set up two theodolites that have been aligned with each other, align the reference ruler, add scale information to the theodolite measurement system, and establish the theodolite measurement system; In the theodolite measurement system, two theodolites are used to align the cubic prism, determine the position relationship between the cubic prism coordinate system and the two theodolites, use the two theodolites to measure the prism crosshairs, determine the origin of the prism coordinate system, and establish the prism coordinate system in the theodolite measurement system.

4. The high-precision electric axis and mechanical axis calibration method based on joint measurement according to claim 1, characterized in that: Use a single-camera measurement system to obtain the positions of the target points on the side and back of the T-type fixture in the radar mechanical axis coordinate system, including: Use a single-camera measurement system to monitor the position of the target point movement at the edge of the antenna, as well as the position of the target points on the side and back of the T-type fixture; Two circles are fitted respectively using the moving position of the target point at the edge of the antenna. The straight line passing through the center of the circle and perpendicular to the circular plane is the radar mechanical axis. The intersection of the two straight lines is the origin of the radar mechanical axis coordinate system. The positions of the target points on the side and back of the T-type tooling in the radar mechanical axis coordinate system are obtained.

5. The high-precision electric axis and mechanical axis calibration method based on joint measurement according to claim 1, characterized in that: The method of using the target point coordinates on the back of the T-shaped fixture as a common point to deduce the geometric relationship between the radar mechanical axis coordinate system and the prism coordinate system specifically includes: Select more than three common points that have both the radar mechanical axis coordinate system and the prism coordinate system, list the error equation of each common point, calculate the conversion parameters between the radar mechanical axis coordinate system and the prism coordinate system by the least squares principle, eliminate the common points with large errors according to the errors between the converted coordinate positions and the measured coordinate positions, and calculate the conversion parameters between the radar mechanical axis coordinate system and the prism coordinate system by the least squares principle for the remaining common points.

Images