中文摘要：

为了提高无需测距的跳距矢量（DV—Hop）定位算法在节点随机分布且拓扑动态变化的无线传感器网络中的节点定位精度，在分析DV—Hop算法实现思想的基础上，针对多边定位法计算出的估计坐标存在较大误差的问题，采用泰勒级数展开法构建了坐标值的数值迭代求精算法，并对改进DV—Hop的性能进行了3个方面的仿真研究：确定了算法迭代步长收敛门限值的选择准则，对比分析了选定门限值条件下DV—Hop算法改进前后的定位性能，给出了不同信标节点和网络节点条件下的统计迭代次数，并以此衡量改进算法的计算量和收敛速度。仿真结果表明，合理选择迭代门限值时，通过适当增加定位节点的计算量．改进算法可明显改善定位精度和定位误差稳定性，是一种可行的无线传感器网络节点定位的解决方案。

英文摘要：

In order to improve the node localization precision of Range-Free-based DV-Hop localization algorithm in wireless sensor networks （WSNs） with randomly distributed nodes and dynamic topology, the improved algorithm is proposed. After analyzing the DV-Hop algorithm, considering the obvious errors of the estimated node coordinates calculated by Polygon-based method in traditional DV-Hop algorithm, the numerical iterative algorithm is constructed by employing Taylor series expansion, and simulation studies for the improved DV-Hop algorithm are conducted. The selection criteria for the convergent threshold of iterative step is determined, the localization performance of the improved localization algorithm is analyzed by comparing with the traditional DV-Hop algorithm under the same condition of selected convergent threshold and simulation parameters, while the calculation amount and convergence rate of the improved algorithm are also measured by the statistic iterations. The simulation results show that by selecting reasonable iterative threshold values and appropriately increasing calculation amount for node localization, the improved DV-Hop localization algorithm greatly improves the localization precision and the error stability, which is feasible for node localization in WSNs with both randomly distributed nodes and dynamic topology.