Research On Evaluation Methods Of Satellite Navigation Signal And System Realization

The performance of the satellite navigation signal directly affects the positioning, navigation, timing and other service performance of satellite navigation system. The purpose of GNSS signal quality monitoring and evaluation is to complete the performace monitoring of GNSS signal, to verify the design method of GNSS signal, to assess the spatial transmission and service performance of GNSS signal, and to provide the support for GNSS signal design and key technoloty in orbit validation. At the same time, the long term signal performance monitoring and evaluation of in orbit satellite can provide important support for the system fault diagnosis and signal integrity monitoring. It is necessary to ensure the security, integrity and stability of the system. Therefore, GNSS signal quality monitoring and evaluation is a key link in the design and operation of the satellite navigation system. The United States and the European Union have attached great importance to the GNSS signal quality monitoring and evaluation work. They both equipped signal quality monitoring systems in their own system.The main work in this paper is the research and analysis of GNSS signal modulation mode, the research and establishment of GNSS signal quality assessment object, evaluation system and method, and the design and implementation of the GNSS signal quality monitoring system based on GPU platform. Firstly, research on GNSS signal modulation mode. This part introduces the principle theory of the variant GNSS signal modulation modes used by the existing GNSS systems in details. Simulations are carried out of these modulation types. Through the comparison of time domain waveform, spectrum and correlation function, the characteristics of different modulation types are summed up, which lay the foundation for refining the object and content of signal quality assessment. Secondly, on the basis of analysis of signal modulation modes, the evaluated object in this paper is pointed out. Combined with the specification of the space interface control document, the evaluation system and specific indicators are established which include time domain analysis, frequency domain analysis, modulation domain analysis, correlation domain analysis and measurement domain analysis. Finally, a real time GNSS signal quality assessment system based on GPU platform is built. The composition, working principle, function module design, hardware design, software design and interface design of the system are discussed in details. According to the algorithms proposed in this paper, the signal quality evaluation software is developed. Through the process of the real signal data, efficient evaluation results are obtained and the correctness of algorithms is verified.The research on the GNSS signal quality monitoring and evaluation is not only the comprehensive measurement of the performance and specification of the GNSS signal, but also the evaluation of system performance from the view of practical application, which is of great significance.