Research On Basdband Processing Algorithm For BOC Signal

Satellite Navigation and Positioning System has developed a single GPS system into theGNSS era, Global Navigation Satellite System include: American GPS, European Galileo,Russian Glonass,Chinese BeiDou, Regional Navigational Satellite System include: JapaneseQZSS, Indian IRNSS and so on. Spectrum resources is limited,as the number of signal’sincrease,it will result in signal interference among different or same system.BOC modulationtechnique is a way of system compatibility,it is an development direction of major SatelliteNavigation and Positioning System.we have researched on baseband processing algorithm forBOC signal in this paper, The main work includes:Research on principle and characteristics of BOC modulation singal, we summarizesystem compatibility in GNSS era, BOC modulation technique’s application and developmenton Satellite Navigation and Positioning System.we introduce the BOC modulation theory,andanalysis it’s autocorrelation and Spectral characteristics.Then we simulate GPS L1C base onIS-GPS-800document, not only explore autocorrelation and Spectral characteristics of GPSL1C,but also Secondary code.we focus on exploration of BOC signal’s several significantparameters,such as RMS bandwidth, Spectral Separation Coefficient and valid rectanglebandwidth,the result shows that GPS L1C signal has better tracking accuracy andanti-interference property than traditional signal.Research on unambiguity acquisition for BOC signal. we summarize serial acquisition intime domain and parallel acquisition in frequency domain for traditional signal,because ofBOC signal’s autocorrelation has multi-peak,it would result in error acquisition and loseacquisition,we Systematically Analyse the basic principle of BPSK like method,SCPC andASPeCT,then we used GPS L1C signal to being an signal source for testing these threemethods.we face on the defect of primary multi-peak remove algorithm,and proposed onethought about BOC signal’s separation and reconstitution.Direction by this thought,we realizeBOC signal’s unambiguity acquisition algorithm base on separation and reconstitution ofBOC/PRN cross-correlation or BOC autocorrelation.the result illustrate the algorithm be ableto remove sub-peak of sine or cosine phase BOC signal which modulation order is random,atthe same time, it reserves features of Narrow correlation peak, the peak’s width is1/kchip.when the detection probability is90%, separation and reconstitution algorithm’sperformance is1.8dB better than ASPeCT, however, BPSK like method’s performance is0.6dB lower than SCPC, the reason is BPSK like method will lose0.5~0.8dB energy inacquisition processing.Research on unambiguity tracking for BOC signal. When we adopt traditional code lock loop to track BOC signal,it will be arise several noncentral null point, these point willlead to tracking ambiguity.we explore the principle of linearization discriminator curve baseon multi-correlation weighted by coefficients,and analyze the relationship betweenlinearization performance and the number of observations,correlation interval by simulationexperiment.the result indicate discrimination range increases along with the number ofobservations increases, but also as a result of correlation interval’s increase,but discriminationgain has an opposite trend,there is a contradiction between discrimination range anddiscrimination gain by selecting the number of observations, correlation interval. Throughthis situation,we proposed BOC signal unambiguity tracking algorithm base on switchoverlinearization discriminator, we select some observations to structure discriminator, whichthe number of observations and correlation interval is controlled by switch, it’s aim to obtainthe best comprehensive performance.