Simulation Generate And Performance Analyse On BDS-3 B1C Signal

Beidou system is a satellite navigation and positioning system independently researched and developed by China with independent intellectual property rights.It has important strategic significance for China's military,political and economic aspects.At present,the world's major countries are vigorously promoting the modernization process of their satellite navigation systems.Although China's Beidou system started later than the US GPS and Russian GLONASS systems,But China also announced entry into the global era in December 2018.As a civilian global signal,the B1 C signal has a common compatible interoperability frequency with the L1 C signal of the GPS system and the E1 OS signal of the Galileo system.At the same time,it take a new time domain modulation method which different from GPS system and Galileo system.Under the demand of compatibility and interoperability among major navigation systems around the world,it has given important research value on B1 C signals.Therefore,the design and implementation of B1 C signals and the analysis of synchronization algorithms will be the research hotspots in the next few years.In order to realize the real-time generation and performance analysis of B1 C digital intermediate frequency signal hardware of BDS-3,based on the existing research,this paper studies the simulation and generation of B1 C signal and its performance,and achieves the following results:(1)On the basis of the theoretical analysis of the spread spectrum communication,pseudo-random sequence and signal phase modulation characteristics which required for the modulated signal,the traditional BPSK-R modulated signal,the new BOC modulated signal and the modern GNSS modulated signal are completed.Theoretical study and simulation analysis of power spectrum and autocorrelation properties,and give relevant conclusions.(2)According to the document of B1 C signal issued by the Beidou Office,based on the excellent characteristics of the Barker code,the B1 C signal navigation data simulated by using 100 bits virtual data,and the corresponding hardware simulation generation is completed.Aiming at the pseudo-code generation of B1 C signal,a dual-port generation method that saves hardware resources and strong real-time which is presented,and hardware generation design and implementation are implemented.At the same time,the hardware implementation of carrier and sub-carrier generation is completed.(3)Aiming at the inherent characteristics of the pilot component of B1 C signal,an online generation scheme that is easy to implement,real-time and saves storage resources is improved,which solves the problem that the signal containing imaginary operation in signal processing is difficult to implement in hardware.In addition,by adopting precise phase control and clock control,the phase relationship and the initial edge alignment relationship between the components required in the document of B1 C signal,and the hardware implementation of each component of the B1 C signal and the entire B1 C signal is completed.Subsequently,based on software platform and hardware architecture such as spectrum analyzer and oscilloscope,the modulation process is verified,and combined with GNSS signal theory,the correctness of the designed B1 C signal is double verified,and the results are analyzed.(4)Qualitative and quantitative analyse the isometric length of the Weil code and the gold code sequence from the generation mode,autocorrelation and cross-correlation properties,and the Welch lower bound and the Levenshtein lower bound of the correlation extremes of the two are given;in addition.From the perspective of the modulation methods used by B1 C,L1C and E1 OS signals,the code tracking performance between B1 C,L1C and E1 OS signals is qualitatively and quantitatively analyzed,and the CT-SSC analysis expressions of NELP and DP loop models are given.At the same time,analyzing the Cramer-Rao lower bound of the model.For the simulation of the B1 C signal of BDS-3,the improved generation scheme is not limited to the field of navigation signal processing,and can extend to the signal processing where involving imaginary operation.The generated B1 C signal not only provides a hardware design reference for the receiving terminal of the Beidou system,but also provides a test signal for the signal receiving process.In addition,the analysis results of the pseudo-code sequence performance can be used as a reference for judging the pseudo-code ranging performance of the GNSS new institutional signal,and the code tracking performance analysis of the modulated signals used for the B1 C,L1C and E1 OS signals can reveal this in essence.The tracking performance of the three types of signals not only provides an evaluation reference for compatible interoperability between modern GNSS systems,but also provides an index design reference for the terminal design of GNSS modernized new system receivers.