Method for detecting multiple GPS (global positioning system) satellite weak echo signals

Abstract

The invention discloses a method for detecting multiple GPS (global positioning system) satellite weak echo signals. The method comprises steps as follows: a modulation parameter and a C / A code disclosed by a GPS are used for performing separation reconstruction on a GPS signal received by a reference channel, and a reference signal is obtained; direct waves and multiple paths of the direct waves are inhibited for the echo signals; circular cross-ambiguity function processing is performed on an echo channel signal and different reference signals respectively, and multiple delay-doppler spectra are obtained; the multiple delay-doppler spectra are subjected to TF-LV coordinate transformation, and multiple detection quantities are obtained and superposed; the best detection threshold is obtained according to probability distribution of the detection quantities and compared with peak values of the detection quantities, so that the multiple GPS satellite weak echo signals are detected. The method can have a good detection property for multiple GPS echo signals in a low signal-to-noise ratio environment.

Description

technical field [0001] The invention belongs to the technical fields of communication technology and satellite signal processing, and in particular relates to a method for detecting weak echo signals of multiple GPS satellites. Background technique [0002] With the continuous development of space technology, the signal form of GNSS (Global Navigation Satellite System) has become more and more diverse and mature. It is of great significance to use widely distributed GNSS navigation satellites as external radiation sources to detect targets. Taking the most mature GPS satellite system as an example, some domestic and foreign literatures have shown that GPS is feasible as an external radiation source for target detection. And the detection performance is excellent. However, traditional GPS external radiation source echo detection methods are based on the analysis and processing of a single GPS satellite signal. In fact, GPS satellite signals all work in one frequency band, an...

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Problems solved by technology

[0003] People such as Wang lei have introduced the positioning system of multiple CDMA radiation sources on the ground, but the direct wave of this system is directly drawn from the base station with a cable, so it is not suitable for GPS satellite direct wave extraction (WangLei, Wang Jun, Xiao Long. Passive location and precision analysis based on multiple CDMA base stations[C],Radar Conference,2009IET International,2009:1-4)

People such as Michael Edrich have introduced the echo detection system based on ground FM / DAB / DVB-T radiation source, but this system separates signal by the difference of signal frequency band, so it is not suitable for the GPS signal (Michael Edrich, Alexander Schroeder, Fabienne Meyer.Design and performanceevaluation of a matureFM / DAB / DVB-T multi-illuminator passive radar system[J],IET Radar Sonar Navig,2014,8(2):114–122)

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