An acquisition and tracking system based on a relay terminal and an on-orbit phase calibration method

Abstract

An acquisition and tracking system based on a relay terminal and an on-orbit phase calibration method, the system includes a Ka relay antenna, a directional coupler module, a first filter module, a second filter module, a first low-noise amplifier module, a second Low noise amplifier module, single channel modulation module, Ka / C frequency conversion module, capture and tracking module and servo control module. The on-orbit phase calibration method uses the characteristics of the pitch and azimuth orthogonality, and the pitch is 90° ahead of the azimuth. When the single-channel modulation module and the channel N phase shifter change linearly from 0° to 360°, the relative difference between the sum and difference channels is calculated. Phase error, and on-orbit automatic angle compensation. Compared with the method of using ground calibration tower phase calibration and setting a fixed phase value in the existing satellite technology, the present invention ensures the accuracy of angle compensation, improves the simplicity, real-time and repeatability of phase calibration, and reduces the Error cross-coupling term due to phase difference.

Description

technical field [0001] The invention relates to an acquisition and tracking system based on a relay terminal and an on-orbit phase calibration method, which are mainly used in various low-orbit spacecraft relay acquisition and tracking systems, and belong to the technical field of satellite radio tracking and measurement. Background technique [0002] The Σ and Δ signals formed by the target signal entering the antenna pass through a long channel respectively. When reaching the single-channel modulator, the phase relationship between Σ and Δ often changes over time due to changes in various factors such as temperature and circuit parameters. That is, it is not possible to maintain the adjusted phase relationship all the time. [0003] This relative phase change of the sum and difference will cause the azimuth and pitch error characteristics to deteriorate, such as the slope of the error characteristic curve becomes smaller, the polarity of the error characteristic changes, a...

AI Technical Summary

Problems solved by technology

[0007] 1) The phase calibration process is complicated: the satellite-ground system equipment participates in the calibration, or establishes a ground calibration tower for phase calibration. The calibration process involves many equipment, high cost, and complex system

[0008] 2) The accuracy of phase calibration is not high: the higher bits of the phase shifter are used for phase adjustment to achieve the phase consistency of the sum signal Σ and the difference signal Δ, the phase calibration accuracy is low, and the residual part of the cross-coupling term

[0009] 3) Poor real-time performance and poor repeatability: the method of establishing a calibration tower is adopted, and the repeatability of the equipment is poor after launch

The ground tracking accuracy analysis method has a certain hysteresis and cannot realize real-time automatic phase calibration on orbit

[0010] Therefore, the traditional phase calibration method is not applicable, and cannot meet the task requirements of simple and easy phase calibration of relay terminals, high precision, small coupling, high real-time performance, and strong repeatability

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