System calibration test method based on GNSS signal quality evaluation

Abstract

The invention relates to a system calibration test method based on GNSS signal quality evaluation, which comprises a calibration device test and a receiving channel absolute time delay and variable quantity test; the calibration device test comprises a vector network analyzer time delay measurement precision test and a broadband oscilloscope time delay precision test; a vector network analyzer time delay measurement precision test specifically comprises the following steps: S1, enabling a vector network analyzer to carry out a self-calibration test; s2, according to different RF frequencies and bandwidths, straight-through vector calibration is carried out; s3, connecting the tested piece, and testing the group delay characteristic of the standard delay line; the broadband oscilloscope time delay precision test specifically comprises the following steps: generating a pulse-modulated radio frequency signal by using a vector signal source; dividing pulse-modulated radio frequency signalto two paths, wherein the one path is sent to an oscilloscope as a reference channel, and the other path is connected with a standard delay line for testing; and eliminating the influence on the stability of the whole system instrument by adopting a comparison method; The method has the advantages of being high in precision, easy to operate and high in efficiency.

Description

technical field [0001] The invention belongs to the technical field of antenna signal calibration test methods, and in particular relates to a system calibration test method based on GNSS signal quality evaluation. Background technique [0002] In the GNSS signal quality monitoring and evaluation system, the high-precision measurement of the absolute time delay and change of the receiving channel has been a technical problem that has plagued the engineering community for many years. At present, there are mainly the following implementation methods. [0003] 1) Vector network analyzer. This is a method commonly used by many GNSS signal quality monitoring and evaluation systems at home and abroad. It is simple, easy to implement, universal, and efficient. It can measure multiple parameters including amplitude-frequency response and group delay at the same time, and the efficiency is high. The disadvantage is that there is a contradiction between accuracy and resolution durin...

AI Technical Summary

Problems solved by technology

The advantage of this method is that the concept is clear, the method is concise, and it can theoretically achieve infinite precision delay measurement. The disadvantage is that the stability of the reference time baseline is not high.

Moreover, the greater the channel delay, the worse the accuracy of the measured delay data

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