The Fast Acquisition Technology Of Multi-mode Navigation Signals Based On The BOC Signals

With the development of the BeiDou satellite navigation system of our country (region),BeiDou System has begun to provide services to the Asia-Pacific region. BeiDou satellitenavigation system (BDS) officially entered the marketing application stage, and the satellitenavigation industry in China will usher in a golden age of rapid development. BOC (binaryoffset carrier) modulation signal is a new type of navigation signal that BeiDou satellitenavigation system plans to use, the signal can make full use of the limited frequency ofnavigation, improve the positioning accuracy, and be compatible with other systems. The fastacquisition technology of Multi-mode navigation signals based on the BOC can provide areference for the BeiDou navigation signal receiver, at present has become one of the hottopics in the field of navigation.This article studies BOC modulation signal acquisition technology and proposes newacquisition methods. First of all, the production mechanism of BOC modulated signals areanalyzed and simulated, combined with a variety of BOC modulation have been proposed,such as BOC (x, y), MBOC (6,1,1/11) and AltBOC (15,10),this article analysis the powerspectrum and autocorrelation characters。Then through in-depth analysis of the current BOCmodulation signal capture technology, tow development directions of acquisition aresummarized in this paper. The BOC autocorrelation function (Autocorrelation function,ACF) reconstruction as the entry point for the new algorithm has many methods in thisdirection, such as ASPeCT,"filtered" and OQCC. Based on the research of above methods,this article proposes new BOC autocorrelation function reconstruction algorithms. Finally,through simulating above methods and comparing with other algorithms, this paper proves theeffectiveness of the new algorithms. In addition, the impact of the new algorithms of thesubsequent tracking loop error is simulated and analyzed.The main innovation and research results of this paper are summarized as follows:(1) Aiming at the shortage of the existing BOC modulation signal autocorrelationfunction reconstruction methods, through in-depth study of the autocorrelation function of theBOC modulated signal and existing acquisition algorithms, this paper puts forward a kind ofalgorithm to eliminate even peaks of BOC autocorrelation function-EPE (Even Peak Elimination). Simulation results show that, EPE algorithm is simple and feasible, caneliminate even peaks of BOC autocorrelation function, and increase the ratio of the main andsecondary peaks autocorrelation, thereby it can reduce the acquisition ambiguity of BOCsignal.(2) For the low order BOC signals,such as BOC (n, n), MBOC (6,1,1/11), EPEalgorithm is optimal acquisition method, but the capture effect of BOC signal on the highorder will reduce. Aiming at the shortcomings of EPE algorithm, learning OQCC algorithms,this paper proposes another reconstruction method of BOC signal autocorrelation function--RQCC (Remove Quadratic BOC Cross-Correlation), the RQCC algorithm applies to a varietyof BOC modulation signals. The simulation shows that the autocorrelation function of BOCsignals of each order can be improved significantly.