The Research And Realization Of Unambiguous Acquisition Algorithm On BOC Signals

With the advancementin the navigation system, signals are more and more crowded.Spectrum resource can be reasonable and effectively used with the BOC(Binary OffsetCarrier). Compared with traditional GPS signal, BOC modulation signals use the binaryoffset carrier, which moves the spectrum from carrier frequency to side band. Then theinterference of spectrum is effectively avoid. Compared with BPSK modulation, the peakof autocorrelation function for the BOC signal is sharper. Therefore, BOC signals canprovide higher code tracking accuracy, stronger anti-interference ability and bettermultipath resolution. Compared with traditional GPS signals, the autocorrelation functionof BOC signals have a profile with more than one peak, which allow acquire onsecondary peaks with a high probability. With this great drawback, the acquisitionalgorithm of BOC signals is complex than traditional BPSK signals. So the research ischoosed on unambiguous acquisition algorithm for BOC signals.In this paper, the unambiguous acquisition algorithms for BOC(n,n) signals andBOC(m,n) singals are researched. Firstly, the background and significance of thisresearch is introduced, including the development trend and research status ofunambiguous acquisition algorithm on BOC signals. Subseqently, the characteristics ofBOC signals are analyzed, including signal generating, power spectral density andautocorrelation function. The advantages and disadvantages of BOC modulation in thefied of navigation are analyzed. Secondly, the typical acquisition methods for BOC(n,n)singals are introduced. On this basis, a new unambiguous acquisition algorithm isproposed. For BOC(m,n) signals, two unambiguous acquisition algorithms are proposedin the time domain and frequency domain, respectively.With the simulation on Matlab theimproved algorithm is verified. Finally,based on the previous theoretical analysis andsimulation, the implement on FPGA chip for the unambiguous acquisition algorithm ofBOC(m,n) singnals is completed. At last, its module division is showed, the function ofeach module is described, and the figures of Modelsim simulation are given out.