Satellite Navigation Civil Signal Time-frequency Domain Analysis And Evaluation

Global Positioning System(GPS)has been widely used in aviation,maritime,national defense and other applications.The third-generation of China's BEIDOU-3 navigation system has successfully launched its 54 th satellite,which will very soon implement the BEIDOU-3 system to become a global navigation network.Satellite navigation downlink signals directly determine the performance of the navigation system,it is necessary to carry out effective evaluation and analysis of the time domain and frequency domain indicators,and form a general quality evaluation system.On the one hand,Global Positioning System(GPS)'s Civil signal has been combined with the Interface Control documents,and Performance Standards established a series of perfect performance evaluation parameters of the system,which is covering time domain and frequency domain.Meanwhile,for the civil signal of third generation of BEIDOU system,the time domain and frequency domain evaluation standard are still in a stage of demonstration and analysis,which need combine a large number of evaluation and validation test results of actual users on ground to analyze generally.On the other hand,for civil aviation users with a very high demand for positioning performance and speed measurement performance,both GPS and BEIDOU-3 must meet the requirements of the International Civil Aviation Organization on their service quality,and any potential service degradation caused by signal distortion must be considered in the study of signal time domain and frequency domain evaluation.Signal distortion caused by payload anomalies is very rare,but once it occurs,it may pose a major security threat to civil aviation users.Based on the above background,in order to evaluate the signal quality of civil signals of BEIDOU system and Global Positioning System,Time-domain and frequency-domain analysis and evaluation of civil signals of BEIDOU B1 I and GPS L1 C/A were conducted.In establishing evaluation perimeters system on the scope of civil signal,in order to capture,tracking performance,the time domain performance curve,the navigation message,power spectrum and a series of civil signal,frequency domain analysis and evaluation respectively,which also analyses the causes of civil signal distortion of all kinds of error sources,analysis of the conclusion for the BEIDOU system time-frequency performance index,which can fully meet the performance requirements of practical application.In considering of,there is still a lack of systematic qualitative and quantitative research for the time domain and frequency domain evaluation and signal distortion analysis of civil signals of BEIDOU-3 system,the time-frequency domain evaluation analysis of civil signal studied in paper has certain reference value for practical application.