Abstract:

Effect of cross correlation on weak global positioning system (GPS) signal acquisition is firstly analyzed, and is considered as a kind of nearfar problem in GPS communication. In order to solve this problem, a sub-space projection algorithm is given and derived theoretically to improve its ability of eliminating nearfar interference. The error analysis of the subspace projection algorithm related to the GPS frequency and code errors during the acquisition procedure is discussed, and experiments are carried out with simulated data and real intermediate frequency data. Results show that in the simulated data case because the frequency and code error are minor and easy to estimate, the sub-space projection algorithm works well in both strong and weak signal environments; while in the real data case the frequency error is difficult to predict, and the sub-space projection algorithm suffers great uncertainty in the weak signal environment.