Acquisition Algorithm of Beidou B1C Signal based on Improved Pseudo Correlation Function

Beidou B1C signal is composed of BOC(I,I) modulated data component and QMBOC(6,1,4/33) modulated pilot component. Its autocorrelation function has multiple side peaks, which leads to large error in its acquisition. To solve this problem, a fast signal acquisition algorithm based on improved pseudo correlation function is proposed. The algorithm acts on the pilot component of the signal, uses absolute amplitude operation to change the direction of one side line of zero crossing, uses square root operation of matrix elements to smooth the main peak, and linearly superimposes the two functions. The algorithm is compared with five existing algorithms. The simulation results show that the algorithm significantly improves the value of main peak, eliminates the side peak, improves the fuzzy acquisition performance, and can capture B1C signal accurately and quickly.