Research And Implementation Of Carrier Capture Tracking Algorithm For Ground-based Navigation System

As a new type of pseudo-satellite navigation and positioning system,ground-based navigation system has the advantages of high accuracy,high flexibility and high scalability compared with traditional satellite navigation system,and is widely used in the fields of deformation measurement,mine detection,urban ranging and military,etc.It has become a major direction of positioning infrastructure construction in some countries.The domestic research on this kind of pseudo-satellite system is only at the level of signal system design,base station layout,traditional transceiver design,etc.The research on the time synchronization technology of this system is not sufficient,and the research on the carrier capture(synchronization)and pseudo-code synchronization(tracking)algorithm related to the time synchronization performance is mostly focused on the theoretical simulation stage,and the research on the combination of ground-based navigation system platform and the verification of capture and tracking algorithm is not sufficient.The research on the integration of ground-based navigation system platform with the verification of capture and tracking algorithm is not sufficient.To address this situation,this thesis designs and completes a carrier capture and tracking algorithm based on ground-based navigation,and completes the algorithm verification on FPGA platform.The main research contents are as follows:1?Analysis of the shortcomings of traditional satellite navigation systems,research on the development status of ground-based navigation systems,and a detailed discussion on the development of carrier capture and tracking technology related to time synchronization performance in ground-based navigation systems.2?The composition structure,positioning principle and inter-base station time synchronization technology of the ground-based navigation system are studied,the research significance of the carrier capture and tracking algorithm is clarified,the relevant mathematical models and parameter principles in the algorithm design are derived,and the algorithm performance indexes are analyzed.3?On the basis of technical research and theoretical analysis,a ground-based navigation and positioning system with four base stations and one user was successfully built by using optical fiber and optical transceiver to simulate wireless channels in the laboratory environment,and the base station architecture and functions,communication network model were designed and tested to provide a verification platform for the carrier capture and tracking algorithm.4?Combined with the digital IF transceiver scheme,the IF transmitter module based on DPSK modulation is designed as the signal source for algorithm verification,and the Verilog?IP design of direct sequence spread spectrum,shaping filter,direct digital frequency synthesis(DDS)and other modules are realized,and the design and verification of the carrier capture and pseudocode tracking algorithm are completed based on the ground-based navigation system verification platform,and the algorithm is analyzed resource usage and performance indexes.