Satellite Navigation AltBOC Signal And Unambiguous Acquisition Research

Alternating binary offset carrier modulation signal(AltBOC)comes from the binary offset carrier modulation(BOC)signal.Relative to the BOC signal,AltBOC signal has improved in various aspects performance,but complex AltBOC modulation is more difficult to understand,also has ambiguous acquisition problems.Consider the traditional BOC signals and the AltBOC characteristics,this paper complete the following main works:1.On the basis of the sub-carrier of binary offset carrier(BOC)modulation phase jump,analysis performance and characteristics of 2-code AltBOC,then to the 4-code non-constant envelope AltBOC modulation.Through Sub-carrier reconstruct methods to make a constant envelope signal,eventually get constant envelope AltBOC modulation.2.The power spectral density(PSD)and auto-correlation function(ACF)of the constant envelope AltBOC modulation signal and ordinary BOC modulation signal are analyzed and compared.The simulation results show that AltBOC signal to keep the BOC signals high degree of spectrum spectral,it also improve positioning accuracy and enhances multipath rejection.3.According to AltBOC modulation signal ambiguous acquisition problem,puts forward the BPSK-like and |VE2 + P2| two non-ambiguous acquisition tracking algorithm.4.Increase filters in loop,filter out one side of the signal and the resulting signal is correlated with local reference signal and then integral processing can realize BPSK-like method,the method is simple in theory analyze and can eliminate ambiguity problem.The Matlab simulation results show that the AltBOC signal after processed by the algorithm has higher detection probability and shorter acquisition time.5.Increase very early in the correlations and combine with original punctual correlations can achieve |VE2+P2|method,this method can also eliminate the ambiguity problem,and the hardware implementation is simpler.The main peak of correlation function is narrow.The simulation results show that the algorithm has obviously improved performance in the acquisition.