TOA数据处理对NLOS环境下定位精度的改善

基于移动通信环境中非视距(NLOS)传播时延服从指数分布的特性,提出了一种改善移动台定位精度的波达时间(TOA)数据处理方法.NLOS传播时延是TOA测量误差的一部分,是基站与移动台距离的指数函数,具有正偏置的特性,因此TOA测量值越大其误差越大.对所有的TOA测量数据进行分析,仅保留误差最小的3个,然后再采用最小二乘(LS)法估计移动台的坐标.仿真结果表明,该TOA数据处理方法能够明显改善NLOS传播环境下的定位精度,在系统测量误差较小时对LOS传播条件下的定位精度几乎没有影响.

Improvement of the position location accuracy in NLOS environment by TOA data process

Based on the exponential distribution property of the non-line-of-sight(NLOS)propagation delay in the mobile communication environment,a time-of-arrival(TOA)data process method is presented to improve the location accuracy of the mobile station.The NLOS propagation delay is a part of TOA measurement error.It is an exponential function of distance between base station and mobile station and is positively biased.Therefore,the bigger the TOA measured,the greater the TOA error should be.After all of the measured TOA data are analysed,only three one with the minimum error are kept.Then the Least-Square(LS)method is applied to estimate the coordinate of the mobile station.The simulation results show that this TOA data process method can improve the location accuracy in NLOS environment,and it has little disadvantage to mobile location accuracy in LOS environment when the sytem measurement error is low.