Implementation Of Fast Acquisition Algorithm In Beidou Satellite Navigation Simulation System

Beidou navigation system is the national aerospace project with the largest scale,the most complicated technology,the longest construction time,the widest application range and the highest strategic positioning since China was established.With the development of information technology,the implementation of the new generation of strategic policies such as smart city construction,Internet of Things,and the Belt and Road Initiative has put forward higher requirements for the development of navigation systems.After a detailed introduction to the composition and operation principle of the Beidou system,this paper simulates the Beidou signal and improves the receiver's acquisition algorithm.The Beidou satellite navigation simulation platform is built to realize the complete process of the receiver module,as follows:This thesis first introduces the structure and positioning principle of the Beidou system.The function and signal transmission process of the Beidou system are explained from the ground control center,the space satellite network and the user terminal.The receiver principle of the Beidou satellite navigation system is studied.The advantages and disadvantages of the simulation system are analyzed from the perspective of hardware and software.The principle of the capture tracking algorithm in the receiver.Secondly,the composition of the Beidou navigation signal and the spread spectrum modulation method are introduced in detail.The composition of the signal is introduced from the aspects of carrier,pseudo-random code and data code.The most commonly used B1 I and B1 C signals are studied in civilian receivers.The modulation simulation analysis of Beidou signal is carried out by BPSK and QMBOC.Then,the traditional acquisition algorithm has high hardware requirements or slow acquisition speed.This paper improves the PMF-FFT acquisition algorithm and simulates it.The traditional serial search capture,parallel frequency search capture and parallel code phase search capture algorithm are studied and simulated,and the capture speed and accuracy are analyzed.An improved algorithm combining PMF-FFT and parallel code phase is proposed.Simulation analysis,the algorithm can search multiple code phases in parallel through matched filter,which has higher acquisition probability than traditional PMF-FFT algorithm,and the capture efficiency is greatly improved.Finally,the Beidou navigation simulation system was improved,and the fast acquisition algorithm of the receiver module was realized.After thoroughly studying the overall architecture and operation process of Beidou satellite navigation system,the Beidou navigation simulation system is written by C++ language and divided into multiple modules,including main monitoring station,ground injection station,uplink and downlink channel,four satellites and receiving.Machine and so on.The system can realize signal level simulation,including signal generation,acquisition and tracking.The receiver module uses cuda programming to realize parallel code phase fast acquisition algorithm.It can acquire the navigation signal sent by the downlink channel and parse out the navigation message.