A Monitoring Method for BOC Signal Ranging Code

Ranging code monitoring is one of the most important functions of signal monitoring system.However,the received signal is often buried in noise,and the ranging codes are not visible in time domain.The autocorrelation and power spectral density functions of BOC signal were derived,and a BOC ranging code decoding method was proposed in low SNR.In this method,Doppler frequency and code rate were estimated by spectral correlation theory based on signal's cyclostationarity and noise's wide sense stationary.After wiping off the Doppler shift,navigation message bits were determined and removed by slide-correlating a small slice of itself with the whole data.The start of the code was determined by stacking multiple periods of the whole data into a code period,and then the whole data was shifted to the start of the PRN code,and was restacked.Then the individual period of PRN codes was estimated after wiping off subcarrier.This method was verified by simulating BOC(1,1) signal.