A Test Method for Absolute Time Delay of Satellite Transponder

Abstract

A method for testing the absolute time delay of a satellite transponder. First, an angle-modulated microwave signal source is used to output an angle-modulated microwave signal, and then the angle-modulated microwave signal is divided into two paths. One path is input to the entrance of the satellite transponder through an attenuator, and the other path The signal is used as the input of an A / D converter, and the output signal of the satellite transponder is input to another A / D converter after passing through a high-power attenuator. The two A / D converters use the same reference clock to sample data synchronously, and then demodulate the angle modulation signal on the two-way A / D sampled data to obtain the baseband signal of the two-way A / D sampling signal. The two baseband low-frequency periodic signals are compared to obtain the absolute time delay between the two baseband signals represented by the difference in the serial numbers of the sampling points. The number of sampling points multiplied by the sampling period is the absolute Delay, after deducting the delay calibration value of the attenuator and the connecting cable, it is the absolute delay of the satellite transponder.

Description

technical field [0001] The invention relates to a novel method for testing the absolute time delay of a satellite transponder, which is used for precise measurement of the absolute time delay of a transponder navigation signal satellite transponder during the ground test of a navigation satellite, and can also be used for communication satellite transponders and analog frequency converters The absolute time delay is precisely calibrated. Background technique [0002] The satellite navigation system can send high-precision, all-day and all-weather navigation, positioning and timing information, and is an indispensable and important space infrastructure for today's national economy and national defense construction. Satellite navigation and positioning systems are widely used in many fields, including: aviation navigation, maritime navigation, land navigation; space vehicle measurement and control positioning; map surveying and mapping, establishment of geographic information ...

AI Technical Summary

Problems solved by technology

This method needs to lead the reference signal from the satellite body as the local oscillator signal of the test frequency converter, and in the whole star state, the navigation satellite does not provide a reference signal output test port, so the navigation satellite cannot use the existing The method to test the absolute time delay of the transponder can only be tested in the stand-alone and sub-system stages, which leads to the inability to test and evaluate the state of the absolute time delay of the transponder in each stage of the navigation satellite

In addition, the existing method requires a precision time delay test frequency converter. If the input / output frequency band of the satellite transponder changes, it is necessary to replace the precision time delay test frequency converter suitable for the new frequency conversion relationship, so the requirements for the test equipment are relatively high. The connection of the precision time delay test frequency converter will also introduce measurement errors

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