Research Of IMPA And Application In Spread Spectrum Navigation System

In recent years, spread spectrum technology is used widely in many field such as communication, orientation and navigation, distance measurement and so on, because of its strong anti-jamming ability, anti-multi-path and so on However, the precondition of obtaining spread spectrum technology superiority is accurate PN code synchronization, especially for long PN code. Aimed at this problem, a new approach is researched in this thesis, that is Iterative Message-passing Algorithm on Graphs (IMPA), and, the method has been used in spread spectrum navigation system.In this thesis, basic theory of IMPA is introduced, model of Direct-Sequence Spread-Spectrum (DS-SS) signal acquisition using IMPA is designed. Three projects are proposed, they are single DS-SS signal acquisition, multi-path DS-SS signal acquisition and sky-wave acquisition. Algorithmic process, acquisition models of the system and methods of realization are designed. Based on these projects, performance of IMPA acquisition is analyzed. At last, these projects are realized by language C and Matlab.Finally, combining with basic theory of IMPA and DS-SS signal acquisition project using IMPA, hardware project of DS-SS signal acquisition using IMPA is designed. Every module of the hardware project is realized by SOPC, sequential logic simulation result of every module is received. At the same time, the performance of the method such as feasibility, speediness and low complexity are proved strongly by the result of debugging.