A Localization Scheme for Underwater Acoustic Wireless Sensor Networks using AoA

Background: Underwater Acoustic Sensor Networks (UWASNs) have been proposed for the hard oceanographic application where human efforts are not possible. In UWASNs localization is a challenging task due to unavailability of Global Positioning System (GPS), high propagation delay and the dynamic mobility of the sensor nodes due to ocean dynamics. Objective: To address the issues related to the localization of the sensors for the network deployed under water. This paper presents a localization scheme specially designed for UWASNs. Methods: In this paper, we propose a localization scheme using Angle-of-Arrival (AoA) technique for UWASNs. The proposed localization scheme is divided into Angle estimation phase, Projection Phase and Localization phase. The angle estimation phase estimations the angle of the signal arriving at the sensors. The projection phase converts the 3-Dimensional localization problem in equivalent 2-Dimensional by projecting the sensor nodes to a virtual projection plane. In the localization phase, the position of the sensor nodes is estimated based on the Angle-of-Arrival and distance from neighboring nodes information. Results: The simulation result shows that the proposed scheme provides a high localization ratio and Localization coverage with less energy consumption. Conclusion: A distributed range-based localization scheme for UWASNs using AoA technique is presented. The localization scheme projects the sensor nodes to a virtual plane and calculates the angle of signals initiated by the reference nodes. The scheme provides a great success in node localization and network coverage.