面向非完全序列的水下三维传感网定位算法

Non-full sequence-based localization algorithm for 3D underwater sensor networks

针对三维空间节点定位精度低以及算法复杂度高的问题,提出一种面向非完全序列的水下三维传感网定位(NFSL)算法。该算法区别于传统基于序列定位算法,考虑更切实际的信标节点通信范围非全网覆盖的情况。首先,利用3D Voronoi图对三维定位空间进行区域划分,并确定虚拟信标节点以及其阶次序列;然后,根据由接收的信号强度指示(RSSI)所得的未知节点序列与信标节点序列的阶次相关系数得到"最邻近"信标节点并构建最邻近序列表;其次,设计针对非等长序列相似度的算法并利用该算法得到未知节点的非完全序列与最邻近序列表中各序列的阶次相关系数;最后,将该阶次相关系数作为权重实现对未知节点位置的加权估计。仿真实验以信标节点比例、通信半径、节点总数以及网络规模作为变量对NFSL与DV-Hop和质心算法的定位精度进行比较,仿真结果证明了该算法的有效性,且其定位精度随信标节点数的增加而大幅提高,与传统定位算法相比该算法定位精度最大可提高约23%。

Aiming at the problems of low accuracy and high complexity of localization algorithm in three-dimensional space, a Non-Full Sequence-based Localization （NFSL） algorithm for 3D underwater sensor networks was proposed. Different from traditional sequence-based localization algorithms, a more realistic situation where communication range of beacon nodes is not entire network was taken into consideration by NFSL. Firstly, 3D Vorunoi diagram was used to divide the 3D location space and thus virtual beacon nodes as well as their rank sequences were determined. Secondly, the nearest beacon node was obtained according to the rank correlation coefficient between the unknown node sequence Based on Received Signal Strength Indication （RSSI） ~and the beacon node sequence, and the nearest sequence table was constructed. Next, an algorithm which aimed at the similarity of sequences with unequal lengths was designed and utilized to obtain the rank correlation coefficients between the non-full sequence of unknown nodes and each sequence in the nearest sequence table. Finally, the weighted estimation of the unknown node＇s location was realized by taking the rank correlation coefficient as the weight. In simulation experiments, the localization accuracy of NFSL was compared with that of DV-Hop and Centreid by taking the ratio of beacon nodes, communication range, total number of nodes and network scale as variables. The extensive simulation results verified the effectiveness of the proposed algorithm. Besides, its localization accuracy significantly improves with the increasing number of beacon nodes. Compared with traditional localization algorithms, the localization accuracy of NFSL is improved by as much as 23%.