多径信道下扩频导航信号跟踪性能研究

DS/SS navigational signal tracking performance in the multipath channel

针对扩频导航信号多径信道下信号跟踪性能,分析了时延小于一个码片的多径信号对导航信号伪码相位和载波相位跟踪误差的影响,并建立跟踪环路的数学模型,在考虑多径信号的基础上分析了混合信号相位跟踪的数学模型,分析了混合信号下伪码跟踪环和载波相位跟踪环相位跟踪的性能.在数学模型分析的基础上,对伪码相位跟踪和载波相位跟踪性能进行了计算机仿真.结果表明,多径信号引入相位测量误差与多径信号的幅度、相对直达信号伪码相位和载波相位时延有关,并且伪码相位时延与载波相位时延之间相互影响.

Direct sequence spread spectrum （DS/SS） navigational signal tracking performance in multipath chan- nels 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 math- ematical model of the signal tracking loop system was developed. Considering the multipath signals, the mathemati- cal 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.