码分多址定位中时延配对及非视距误差抑制

Delay matching and NLOS error mitigation in CDMA wireless location systems

在利用码分多址(CDMA)蜂窝网信号对运动目标进行定位的过程中,存在各基站与时延参数不能准确配对及非视距(NLOS)误差严重影响定位性能的问题。针对时延参数配对问题,利用CDMA各基站导频序列与其他基站相差64个码片的整数倍这一特性,提出了一种基于移位配准的配对办法;针对非视距误差问题,提出了一种基于假定非视距基站的方差函数,并以此作为权值,利用加权平均的办法实现对目标的定位。仿真分析表明:所提出的方案可以有效地实现各基站与时延的配对,并减小非视距误差的影响。另外,当根据所提方差函数检测出的非视距基站数量较少时,结合Taylor级数展开算法,可以进一步提高对目标的定位精度。

In CDMA wireless location systems, the incorrect delay matching and the non-line-of-sight （NLOS） error seriously limit the localization performance. Due to the difference between the PN-offset of two different bases is the integer multiple of 64 chips, a shifted matching method is presented to match the delay parameters with the base station. In order to mitigate the NLOS error, a function based on the assumed NLOS bases is proposed, and the target location can be obtained by weighted average of the function. Computer simulations are given to illustrate the effectiveness of the proposed method. Furthermore, if the number of the NLOS bases detected by the proposed function is relatively small, the location accuracy can be better improved by using the Taylor series expansion.