一种改进的无线定位算法

An Improved Wireless Location Algorithm Based On Taylor Serise Expansion

Taylor级数展开法和Chan算法是两种性能优良的利用电波到达时间差(TDOA)的定位算法,前者简单实用,但是其缺点是对初值比较敏感；后者在视距(LOS)传播环境下有较高的定位精度,二者结合可以大大提高定位的精度。但是在非视距(NLOS)传播环境下Chan算法精度会受到较大的影响,从而影响到Taylor级数展开法的定位精度。本文根据NLOS传播环境下附加传播时延和均方根时延扩展的统计特性,对NLOS误差的均值和方差进行估计,对TDOA测量值进行修正,采用Chan算法计算初值,再利用Taylor级数展开法进行定位,并与其它两种基于Taylor级数展开法的定位方法结果进行了比较。仿真结果表明,该算法能够提高NLOS传播环境下的定位精度,性能优于另外两种基于Taylor级数展开法的定位方法。

Taylor series expansion and Chan＇ s algorithm are two excellent performance location methods which use the time difference of arrival （TDOA） of the radio wave. The former is simple and practicable but it is sensitive to the initial value. The latter has better accuracy in the line of sight （LOS） propagation environment. The accuracy will be improved greatly if these two methods are used combinedly. But Chan＇ s accuracy degrades greatly in the non line of sight （NLOS） propagation environment and then it will influence the accuracy of Taylor series expansion algorithm. This paper proposes an effective location method which can estimates the mean and variance of the NLOS error with better accuracy in the light of the statistical property of the excessive time delay and the root mean square delay spread in NLOS environment. We correct the TDOA and estimate the initial value with the Chan＇ s algorithm. Then we calculate the coordinate using Taylor series expansion algorithm and compare it with the results of two other methods based on Taylor series expansion algorithm. The result of simulation proves it＇s effectiveness in improving the location accuracy than the other two methods.