Abstract: Based on Time of Arrival（TOA） positioning algorithm, Chan algorithm in line of sight propagation environment has high positioning accuracy and faster convergence rate based on time of arrival positioning algorithm. But its function is obviously decreased in non-line of sight propagation environment. Through comparing each positioning algorithm, it uses Taylor series combined with the least square method for positioning. Then, the positioning accuracy and connection ability are introduced to improve the performance of the algorithm. Finally, the positioning accuracy is analyzed by modeling and mathematical simulation, the results show that the improved algorithm has better positioning accuracy.

Key words: mobile terminal positioning, Time of Arrival（TOA）, least-square method, communication search model, Cramer-Rao Low Bound（CRLB）, Mean Square Error（MSE）

摘要： 基于到达时间的定位算法中，Chan算法在视距环境下有较高的定位精度及较快的收敛速度，但是在非视距环境下算法定位性能明显下降。通过比较各定位算法，采用Taylor级数结合最小二乘法来进行定位，引入定位精度、连接能力来改善算法性能。最后通过建模和数学仿真进行定位精度分析，结果表明改进后的算法有较好的定位精度。

关键词: 移动终端定位, 到达时间（TOA）, 最小二乘法, 通信搜寻模型, 克拉美罗下界（CRLB）, 均方误差（MSE）