A New Rapid Long Pseudo-Code Acquisition Algorithm in DSSS Signals

Long pseudo-code is widely used in spread spectrum communication system, because it has a high chip rate and a strong anti-jamming property. But it brings us lots of difficulty to capture it as its long period. A new method is proposed to solve this problem in this paper, which is based on the excellent correlation characteristics of the long pseudo-code. The new method divides the local pseudo-code sequence into four subsequences, and then each of them is overlapped and accumulated to form four new sequences. Through simple operation of addition, the four new sequences produce two combined sequences as the new reference sequences. At the same time, the received spread spectrum signal´s simple rate is reduced to a quarter of the chip rate. Use the results to do correlation with the two new reference sequences to capture the synchronous pseudo-code. This method not only rapids the acquisition speed, but also improves the precision of frequency offset compensation. The theoretical analysis and simulation results prove that this method has good acquisition effect.