多径环境下CDMA移动定位的时延估计算法

Mobile location positioning time delay estimation algorithm in CDMA multipath environment

针对CDMA移动定位系统中影响定位时延估计准确度的多径干扰问题,提出了一种基于早晚接收机原理的修正最大似然迭代估计算法,该算法对路径时延差在一定的码片间隔范围内,与传统最大似然时延估计器相比,能有效地抵抗多径干扰的影响,仿真结果证明了该算法的有效性和实用性.该算法同样适用于其他基于时间的无线定位系统的时延估计.

Improving the accuracy of location positioning system in cellular network is the key that location based services are widely applied. In this paper, radiolocation methods and implementations are introduced first. In order to mitigate multipath interruption in cellular system, we present a novel maximum likelihood iterative algorithm based on the theory of early-late receiver to estimate the time delay.Between [0.4,1.2] chip period, compared to conventional single path ML receiver, the proposed algorithm effectively resist the interruption of multipath. The simulation result shows that it can improve the accuracy of time delay estimation effectively in mobile location positioning system.It can be applied in other radiolocation positioning system too.