Research On Modern Satellite Navigation Signal Quality Monitoring Technique

Along with the rapid development of satellite navigation technology,global navigation satellite system has become one of important infrastructure.Satellite navigation system must insure service quality,especially the service that relates to life safety.Signal quality monitoring technique aims at insuring service quality,which has two main duties.First is to automatically alarm when signal is deformed.Second is to assess the in-orbit signal quality regularly and find the cause of failure when failure happened.This paper starts with characteristic of time domain of satellite signal and focus on research of signal waveform monitoring algorithm and signal quality analysis algorithm.The first part introduces two traditional ways,correlation peak and Vernier sampling,to analyze time domain.For the correlation peak cannot show the time domain directly and Vernier sampling need high carrier to noise ratio,this dissertation puts forwards a chip domain observable(CDO)algorithm,which takes the advantage of the similarity of navigation signal's chip shape.The CDO measurement can reserve the detail of chip shape and raise the signal to noise ratio effectively.Meanwhile this algorithm is available for new modulations and military code.Then this dissertation analyzes the relationship among CDO,real signal waveform and correlation function which lay the foundation for the post dissertations.The second part puts forward a signal waveform monitoring algorithm based on CDO and a metric select algorithm based on ICAO model to screen out efficient metrics.By theoretical analysis and simulation,this dissertation proves that compared to traditional signal waveform monitoring algorithm,CDO monitoring algorithm not only have better performance than multi-correlator algorithm(can detect more than 25% abnormal events and decrease max track error from 30 m to 10 m in the best case),but also have lower computational complexity(CDO accumulate times is 1/50 of multi-correlator)and stronger applicability to other modulation(monitoring performance different below 1% between two modulation).The third part presents a signal quality analysis algorithm based on the CDO.This algorithm used relationship among CDO,real signal waveform and correlation function can analyze the time domain,frequency domain,correlation domain and measurement domain by only acquiring CDO.This method can overcome the problem of complex analysis indicators and insufficient time domain analysis of the existing algorithm.Then,this chapter uses the algorithm above to analyze the in-orbit signal of BDS,GPS and Galileo.The results show that the BDS is working properly,Some indicators have better performances than other systems.But BDS's partial frequency especially B1 I has worse consistency than other system.When doing relative positioning may cause additional error.Finally,this paper summarizes the all research work and its application.Then,put forward the deficiencies and the future work of the dissertation.The results of this dissertation can be used directly to real-time satellite navigation signal quality monitoring receiver and signal quality analysis system.