Monitoring And Evaluation On Time And Frequency Domain Of Bei Dou Signal In Space

The assessment of navigation signal quality is of great importance factors for ensuring the operation process of a satellite navigation system. Monitoring and evaluation of navigation signal can provide not only a technical support for design of navigation signal but also provide a valuable reference for Chinese scientific researches and engineering application. An accurate evaluating result can ensure the high quality of service performance for navigation satellite system, which will improve the competitiveness of BeiDou in the international areas.The navigation performance for BeiDou navigation satellite constellation and the distortion model of BeiDou signal in space are mainly researched.One hand, the performance of satellite constellation for BeiDou regional navigation satellite system is introduced. According to the BeiDou satellite constellation “5GEO+5IGSO+ 4MEO” and combined with its application in civil aviation, three indexes that are the visibility of Space Vehicle Dilution of precision(DOP) value and horizontal protection level(HPL) value, the statistical characteristics in Asia-Pacific area and the comparison of three indexes for 4 designated user locations were presented by simulation and analysis. The results show that the BeiDou Regional Navigation Satellite System has the ability to provide the ideal number of satellite in sight, better values of DOP and HPL, and can meet the needs of the above three indexes in Non-precision approach(NPA) flight phase;On the other hand, in order to solve the problem of anomaly navigation signal. Firstly, the mathematic models of digital distortion, analog distortion and digital-analog mixed distortion are established in time domain. Then correlation domain and frequency domain for the three models are simulated and analyzed. Finally, correlation loss, pesudorange measurement error and S-curve locking point deviation are used to evaluate the influence of anomaly signal. The results indicate that anomaly waveform, distortional correlation peak and distortional power spectrum of BeiDou signal in space are produced by signal anomaly. Therefore, pesudorange measurement error is generated, ranging accuracy and positioning accuracy of BeiDou are reduced, and the integrity of augmentation system is also reduced.