Research On Acquisition And Tracking Algorithm Of BOC Navigation Signal In New System

The rapid development of satellite navigation systems in various countries in the world has made problems such as the congestion of the spectrum of navigation signals and the shortage of resources in the frequency band increasingly prominent.The emergence of BOC(Binary Offset Carrier)signal modulation method has alleviated the shortage of spectrum resources to a certain extent,and this signal modulation method also ensures the need for accurate positioning of the navigation system.The BOC modulation method realizes the expansion of signal band resources,and the principle is that this signal modulation method can cause the signal to produce a cracking phenomenon,splitting the spectrum of the signal on both sides of the central frequency.After the signal is modulated by BOC,a BOC modulation signal is formed,although the frequency band resources of the signal are expanded,but at the same time its correlation function is no longer the previous single main peak,this multi-peak characteristic will lead to the receiver in the process of signal capture and tracking appears blurry phenomenon,as well as the signal of false capture or even leakage of the situation.Therefore,it is of great practical value to design a fuzzy-free capture tracking algorithm suitable for BOC signals and select the appropriate hardware and software platform to verify the implementation of the algorithm.Firstly,based on the basic principle of BOC modulation,this paper analyzes the basic characteristics of BOC modulation signal,the differences between BOC modulation and BPSK modulation are analyzed and studied,and the power spectral density function and autocorrelation function of the two modulation signals are simulated and analyzed.On the basis of in-depth study of the existing classical navigation signal acquisition and tracking algorithms at home and abroad,combined with the structural characteristics of the modulation signal itself and the signal synchronization algorithm of the new system,a new capture technology is proposed by using the geometric characteristics between the modulation signal related functions to achieve the purpose of eliminating the signal side peaks to obtain better signal capture performance.The main works of this paper are as follows:(1)In this paper,the classical BPSK modulation signal and the new BOC modulation signal are first discussed,and the performance comparison study of the modulation mode of the signal is mainly from the perspective of power spectral density and autocorrelation function.The structural characteristics of the two modulation signals are simulated and analyzed in MATLAB.A deep understanding of the structure of the modulated signal is a prerequisite for the design of the signal capture tracking algorithms.(2)In-depth study of the capture and tracking principle of navigation signals and the classic capture tracking algorithm,and on the basis of the existing basis,the capture tracking algorithm of the new system BOC signal is sorted out and summarized.After summarizing the existing algorithm,combined with the structural characteristics of the new system signal,using the geometric characteristics between modulation signal correlation functions,a new capture technology is proposed,which can eliminate the signal side peaks and obtain better signal capture performance.Compared with other typical algorithms,this algorithm has a better capture effect under the influence of additive Gaussian white noise.(3)A complete satellite navigation signal capture and tracking software simulation system and hardware experimental platform are built,the system is connected and debugged as a whole,the actual satellite navigation signal is collected and received,and the data is saved in the PC terminal,the performance of the improved algorithm is simulated and verified by simulation experiments,the fuzzy capture of satellite signals and stable tracking are realized,and the navigation positioning solution function is initially realized.