中文摘要：

确定节点的自身位置对自组织传感器网络具有重要价值．前人在假定网络具有若干锚点的前提下计算其他节点坐标，如果传感器网络没有配置锚点，则通常的定位算法难以执行．借助节点之间的测距值，引入虚拟锚点和定位可信度的概念，提出一种在节点处实现分布式无锚点定位的算法．针对定位期间的节点位置估算数值，结合邻接信息设计了一种位置变异策略，避免全网定位计算陷入局部最优解．实验结果表明，算法能有效解决无锚点网络的定位问题，在精度和全局能量比率等指标方面达到满意效果．

英文摘要：

Positioning is a fundamental issue for sensor network operation. Knowledge of accurate node location is essential in such network deployment. Many papers in this field focus on anchor-based solutions. The use of anchors introduces many limitations, since anchors require external equipments such as GPS, and that causes actditional power consumption. Eliminating the requirement of anchors in this paper, a competent anchor-free algorithm is presented for distributed localization in sensor networks. Previous localization algorithms assume that there exist some anchor nodes, and then other nodes are estimated to create their coordinates. Once there are not anchors to be deployed, those localization techniques will be invalidated. The novel algorithm is proposed to create some virtual anchors and a virtual coordinate system, which is executed in a distributed fashion with a measured distance between two adjacent nodes. The neighbor information is adopted, and the intermediate estimations of nodes are measured for position mutation according to their reliability criterions. Thus the positioning optimization process of the whole network is avoided falling into a local optimal solution. Simulation results prove that the algorithm can reliably resolve the anchor-free localization problem. It is superior to previously proposed methods in terms of its ability to compute correct coordinates and the global-energy-ratio objective under a variety of conditions.