DS/SS navigational signal tracking performance in the multipath channel

Direct sequence spread spectrum (DS/SS) navigational signal tracking performance in multipath channels was analyzed in this paper. The influence of multipath signals with time delay less than a single chip on the tracking errors of pseudonoise (PN) code phase and carrier phase of navigational signal was analyzed. And a mathematical model of the signal tracking loop system was developed. Considering the multipath signals, the mathematical model for phase tracking of mixed signals was analyzed. Meanwhile, the performances of phase tracking of mixed signals with PN code tracking loop and carrier phase tracking loop were analyzed, respectively. A series of computer simulations on the performances of these two tracking loops were conducted. The simulation outcomes showed that, the phase tracking errors depend on the amplitudes of multipath signals, PN code phase in relation with direct-arrival signals, and time-delaying of carrier phase. Also, it is found that the time-delay of both PN code phase and carrier phase are affected each other.