Sensor Placement Strategies for Target Localization via 3-D TOA Measurements in Underwater Acoustic Sensor Networks

This article investigates sensor placement strategies for three-dimensional (3-D) time-of arrival (TOA)-based target localization in Underwater Acoustic Sensor Networks (UASNs). To mitigate underestimation of localization accuracy in complex marine environments, the actual acoustic ray propagation time is derived, and the TOA measurement variance is estimated using the ray acoustic propagation model. These formulations enable a novel 3-D TOA measurement model, and the trace of Cramér-Rao lower bound (CRLB) for this model serves as the optimization criterion for sensor placement. The MinMax k-Means algorithm is proposed to determine the optimal sensor placement by minimizing the average of the trace of CRLB. Extensive numerical simulations are conducted to demonstrate the effectiveness of the placement strategies.