Experimental Design And Analysis Of GNSS Signal And Information Processing

In recent years,the development of the global satellite navigation industry is booming,and it has experienced the transformation from the GPS era to the GNSS era.The development of GNSS receiver has become a major trend in the development of navigation technology.The signal and information processing technology in GNSS receiver is discussed in this thesis,especially the baseband unit.A multi-mode acquisition system and tracking system based on FPGA platform for different GNSS signals is designed.On this basis,a number of experiments are completed to verify the function of the design system.The main work is as follows:1.Compare the similarities and differences between GNSS signal in navigation structure,pseudo-code character and modulation mode,and then analyze the pain points and difficulties of realizing multi-mode GNSS signal and information processing.2.The key problems involved in the GNSS baseband system are deeply analyzed,and the existing mature algorithms are compared.On this basis,the algorithm carrier of the GNSS capture system and the tracking system is set up,and some key parameters are calculated.3.A design scheme of multi-mode GNSS signal capture system and a design scheme of general tracking loop for GNSS signal are proposed,which is designed and implemented in FPGA platform.The system designed in this thesis is very flexible and can be compatible with GNSS signals of different systems and intermediate frequency signals of different input formats by means of parameter configuration and mode switching.The system has the following characteristics:1)It supports short code signals with different code lengths,different code rates and different code periods.2)It supports different constellation environments,including GPS,Galileo,GLONASS and Beidou system.3)It supports the signals with BPSK and BOC modulation mode.4)It supports the input signals of the arbitrary center frequency.5)It allows the format of input signals to be 2bit-4bit quantized IF signal.6)It supports the input signals in a certain sampling frequency range.4.The module composition of the system is divided and the specific implementation scheme of each sub-module under the general design scheme is proposed.The design basis,design principle and specific configurable parameters of each module are described in detail,and functional simulation of each module is completed on Xilinx Vivado platform.5.Based on the multi-mode system designed in this thesis,the specific experimental scheme is proposed to complete multiple test experiments of GNSS signal and information system,and the experimental results are analyzed.Representative GPS L1C/A,beidou B1 I,GLONASS L1 and Galileo E1 B intermediate frequency signals were selected for the test.The experiments involved mainly include: testing the applicability of the system to different GNSS signals,testing the system's ability to process intermediate frequency signals in different input formats and testing the performance of the capture system,etc.The results of multiple experiments fully verify the feasibility of the proposed multi-mode GNSS baseband signal processing design scheme.