Study of GPS P-code direct acquisition technique

As the typical CDMA application, the spread spectrum PRN codes in GPS are C/A code applied to standard positioning service and P code applied to precise positioning service presently. P code has a higher tolerance to jamming and spoofing compared with the C/A code, C/A code has short length and low data rate, and is vulnerable to interference and spoofing, but P code is usually acquired depending on C/A code. In order to achieve the higher spectrum-spread gain, the better anti-deception and anti-spoofing, P-code direct acquisition should be implemented. A new P code direct acquisition algorithm is proposed by combining the advantages of classical direct acquisition algorithms such as XFAST (Extended Replica Folding Acquisition Search Technique) and average method, and its validity is shown by a simulation experiment. The results show that the algorithm has better acquisition efficiency than XFAST and average method.