System calibration method for antenna phase center of precision ranging system

Abstract

A system calibration method for an antenna phase center of a precision ranging system relates to the technical field of microwave measurement. The method includes the followings steps that of: step 1,establishing a calibration system of the antenna phase center of the precision ranging system in a microwave darkroom environment; step 2, establishing the antenna mechanical coordinate system of theantenna to be tested and the two-dimensional turntable coordinate system corresponding to the antenna to be tested, and calibrating; step 3, calculating the distance D between the precision ranging system of the measured antenna and the precision ranging system of the reference antenna; step 4, designing the rotation track of the two-dimensional turntable and measuring the azimuth and pitch angles; Step 5: Calculating the angle of the electromagnetic wave emitted by the reference antenna to the antenna to be tested; Step 6, calculating the phase center position in the coordinate system of thetwo-dimensional turntable; Step 7, calculating the phase center position in the antenna mechanical shafting. The invention reduces the error of the external auxiliary instrument and greatly improvesthe test accuracy, at the same time, the calibration method has the advantages of high automation degree, few auxiliary instruments outside the system, high test accuracy and simple and reliable method.

Description

technical field [0001] The invention relates to the technical field of microwave measurement, in particular to a system calibration method for an antenna phase center of a precision ranging system. Background technique [0002] In the high-precision radio measurement system represented by the gravimetric satellite micron-level precision ranging system (KBR) and GNSS receiver, the antenna is the reference point for signal reception, transmission and measurement value output. If the phase center of the antenna changes during the measurement period of interest, errors will be introduced in the output ranging value. Accurately knowing the position of the antenna phase center is very important for online and offline calibration of ranging values, ranging accuracy evaluation, and optimal configuration of ranging systems. [0003] The existing typical antenna phase center calibration methods can be divided into two categories: one is based on microwave anechoic chamber and turntab...

AI Technical Summary

Problems solved by technology

This method has better universality, but because it is separated from the precision measurement system, it introduces more noise and environmental interference from external measuring instruments, which reduces the measurement accuracy

[0006] 2. The phase pattern fitting method is used in the specific solution process of the phase center position. This method is related to the order of fitting. If the order is low, the accuracy cannot be guaranteed, and if the order is too high, it will cause the equation to be distorted and generate errors. , so choosing an appropriate fitting equation is critical, and it has relatively large limitations in use.

In addition, the least squares fitting method used in the advanced method can only reduce the random error of measurement, but cannot improve the measurement accuracy, that is, reduce the systematic error

[0007] 3. In the process of solving the phase center, the emission characteristics of the antenna phase center are not considered as a whole, and the scanning range of the design pattern is not targeted, so there is a systematic deviation in the calculation accuracy of the phase center within the required measurement beam range

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