Prformance Analysis Of BOC Modulation System And Study On Synchronization Technology

Binary offset carrier modulation(BOC) with the special performance, has beenwidely applied in the new generation global satellite navigation system, but thenature of its special autocorrelation function of multi-peak poses a potential threatfor BOC code synchronization. So how to reduce the effects of side peak at thereceiver, at the same time, make the excellent split spectrum performance of BOC todemonstrate maximum becomes critical.This paper first introduces the basic BOC modulation and MBOC, AltBOCmodulation which derived from the basic BOC modulation, and focus on a varietyof statistical characteristics of all these modulations, and then summarizes thecorresponding characteristics. Analysis of the selected parameter, the effect ofbandwidth limitation and the RMS bandwidth on the performance of BOCmodulation system. Based on these theories, focus on the study of synchronizationtechnology for BOC code.Based on the study of existing methods of capture, the existing unambiguousacquisition algorithm can be summarized into two categories, namely spectrumreconstruction by shifting and smoothing for the spectrum, and the directreconstruction technology for autocorrelation function. Research on the advantagesor disadvantages of the FOB algorithm, SOB algorithm, filtered algorithm, ASPeCTalgorithm, SCPC algorithm and OQCC algorithm. Then by the waveformreconstruction ideas, code parallel acquisition algorithm, derives a new design forthe unambiguous algorithm, and simulation the acquisition process.Then analyzes the principle and working process of the classical tracking loopNELP, VNELP, and in order to achieve the goal of obtaining an unambiguoustracking, direct transformation the loop structure is better than taking time to correctthe tracking errors. The classical NELP tracking loop was improved by using thenew algorithm, in order to make the correlation detector output curve of the newloop seems like the correlation detector output curve of the BPSK modulation, thatis to say there is only one zero crossing and reach unambiguous tracking purposes,and study on the relevant time interval how to effect the tracking loop. At last, thetracking error are analyzed, and compared with the Cramer-Rao bound andBayesian bound.