A rotatable dual-antenna active polarization calibration device and its polarization calibration method

Abstract

The invention discloses a rotatable dual-antenna active polarization calibration device and a polarization calibration method thereof. The device is equipped with a polarization filter at the interface of the receiving antenna and the transmitting antenna; the rotatable dual-antenna design is adopted, the receiving Different attitude combinations of antennas and transmitting antennas can form different polarization combinations. Since each antenna in the designed rotatable dual-antenna active polarization calibrator PARC can be rotated independently, controlling the combination of PARC receiving antenna and transmitting antenna in different polarization modes can obtain various forms of PARC Polarized scattering matrix. Installing the PARC polarization calibration device proposed by the present invention, adjusting the delay parameters, controlling the rotation mechanism, and making the PARC rotate at a constant and slow speed can complete the calibration work for any target to be calibrated. By installing a polarization filter at the antenna interface, the polarization isolation of the receiving and transmitting antennas can be greatly improved, which is conducive to improving the accuracy of polarization calibration.

Description

technical field [0001] The invention relates to the technical field of antenna active polarization calibration, in particular to a rotatable dual-antenna active polarization calibration device and a polarization calibration method thereof. Background technique [0002] In the measurement of the radar target polarimetric scattering matrix (PSM), the received signal is not only related to the polarimetric scattering matrix of the target to be measured, but also related to the characteristics of the transmitting channel and receiving channel of the measurement system. Considering the existence of cross-coupling and gain imbalance between the polarization channels of the radar, the relationship between the PSM measured by the target and the real value is as follows: figure 1 Shown (see literature [1] Xiao Zhihe, Chao Zengming, Jiang Xin, Wang Chen. Radar target polarization scattering measurement technology [J]. Systems Engineering and Electronic Technology, 1996, (3): 13-32.). ...

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Problems solved by technology

[0029] (1) The receive polarization and transmit polarization of the PARC antenna are always orthogonal to each other, and the polarization of the transmit and receive antennas cannot be combined arbitrarily, which greatly reduces the form of its theoretical polarization scattering matrix, and many special forms of polarization scattering The matrix cannot be obtained by this single-antenna PARC, such as the identity matrix, which limits its application range;

[0030] (2) Since the solution is to measure the PARC of several antenna rotation angles to obtain the measured data, when there is a small rotation angle error in the measurement, it will affect the calibration accuracy;

[0031] (3) The robustness of the polarization calibration parameter extraction algorithm using this PARC is poor: once there is an abnormal value or a large error in the system measurement value at a certain moment during the calibration process, the accuracy of the extracted calibration parameters will be greatly reduced;

[0032] (4) Since a pair of orthogonally polarized feed sources work at the same time, it is impossible to use a polarization filter device to improve the polarization isolation of the antenna, which greatly affects the polarization calibration accuracy

[0041] (1) The technical design is very complex

This kind of digital PARC has very high requirements on the sampling rate of A / D and D / A. The timing logic of the digital radio frequency memory circuit is complex, and the writing and reading of signals and delay processing and other operations need to be controlled by clocks. In the running circuit, competition and risk are prone to occur (see literature [4] Xiao Hanbo. Digital radio frequency memory and its application in radar signal simulation [J]. Guidance and Fuze, 2002,23(3):25-29.) , so that the whole system cannot work stably and normally;

[0042] (2) The calibration parameter solution process and algorithm are complex;

[0043] (3) The cost is high, the reliability and stability need to be verified, and there are no real products and practical application reports.

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