基于虚拟时延的LOS/NLOS通用TDOA算法及测高误差修正

A General TDOA Algorithm for LOS/NLOS Based on Virtual Time Delay and the Height Measurement Error Correction

基于到达时间差(TDOA)的无线终端定位算法多数适用于视距(LOS)环境,其用于非视距(NLOS)环境下时定位精度不高。而从TDOA的测量数据上区分LOS、NLOS环境非常困难,为此,提出一种适用既适用于LOS环境也适用于NLOS环境的TDOA算法:将多径效应等因素所致的时间误差合并成为虚拟延时,建立以终端坐标、虚拟延时因子为未知数的方程组。通过迭代,解决方程组的欠定问题,估算出终端的坐标。同时,虑及低仰角传输时电波折射对测高的影响,采用电波折射误差修正的简易模型,对测高进行修正。测试数据比对表明:该算法定位精度较高。

Most of the wireless terminal location algorithms based on time difference of arrival （TDOA） are suitable for the lineof-sight （LOS） environment, but their accuracy is not high when they are used in the non-line-of-sight （NLOS） environment. Howev-er, it is very difficult to distinguish LOS from NLOS environment in terms of TDOA measurement data. Therefore, a TDOA algorithmsuitable for both LOS and NLOS environment is proposed： The time error caused by multipath effect is combined into virtual delay.A set of equations with terminal coordinates and virtual delay factor as unknowns is established. Through iteration, the problem ofunderdetermined equations is solved, and the terminal coordinates are estimated. At the same time, considering the effect of radiowave refraction on altimetry when transmitted at low elevation angle, the simple model of radio wave refraction error correction isused to correct the height measurement. The comparison of test data shows that the algorithm has high positioning accuracy.