Luo Junhai, Yang Yang, Wang Zhiyan, Chen Yanping, Wu Man
School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
Sensors (Basel). 2020 Jul 31;20(15):4293. doi: 10.3390/s20154293.
As one of the important facilities for marine exploration, as well as environment monitoring, access control, and security, underwater wireless sensor networks (UWSNs) are widely used in related military and civil fields, since the sensor node localization is the basis of UWSNs' application in various related fields. Therefore, the research of localization algorithms based on UWSNs has gradually become one of the research hotspots today. However, unlike terrestrial wireless sensor networks (WSNs), many terrestrial monitoring and localization technologies cannot be directly applied to the underwater environment. Moreover, due to the complexity and particularity of the underwater environment, the localization of underwater sensor nodes still faces challenges, such as the localization ratio of sensor nodes, time synchronization, localization accuracy, and the mobility of nodes. In this paper, we propose a mobility-assisted localization scheme with time synchronization-free feature (MALS-TSF) for three-dimensional (3D) large-scale UWSNs. In addition, the underwater drift of the sensor node is considered in this scheme. The localization scheme can be divided into two phases. In Phase I, anchor nodes are distributed in the monitoring area, reducing the monitoring cost. Then, we address a time-synchronization-free localization scheme, to obtain the coordinates of the unknown sensor nodes. In Phase II, we use the method of two-way TOA to locate the remaining ordinary sensor nodes. The simulation results show that MALS-TSF can achieve a relatively high localization ratio without time synchronization.
作为海洋探索以及环境监测、访问控制和安全保障的重要设施之一，水下无线传感器网络（UWSN）在相关军事和民用领域得到了广泛应用，因为传感器节点定位是UWSN在各个相关领域应用的基础。因此，基于UWSN的定位算法研究逐渐成为当今的研究热点之一。然而，与陆地无线传感器网络（WSN）不同，许多陆地监测和定位技术不能直接应用于水下环境。此外，由于水下环境的复杂性和特殊性，水下传感器节点的定位仍然面临挑战，如传感器节点的定位率、时间同步、定位精度以及节点的移动性等。在本文中，我们针对三维（3D）大规模UWSN提出了一种具有无时间同步特性的移动辅助定位方案（MALS-TSF）。此外，该方案考虑了传感器节点的水下漂移。该定位方案可分为两个阶段。在第一阶段，将锚节点分布在监测区域，降低监测成本。然后，我们提出一种无时间同步的定位方案，以获取未知传感器节点的坐标。在第二阶段，我们使用双向到达时间（TOA）方法定位其余普通传感器节点。仿真结果表明，MALS-TSF在无时间同步的情况下能够实现较高的定位率。
