3D Underwater Sensor Network Localization

We transform the 3D underwater sensor network (USN) localization problem into its 2D counterpart by employing sensor depth information and a simple projection technique. We first prove that a nondegenerative projection preserves network localizability. We then prove that given a network and a constant k, all of the geometric k-lateration localization methods are equivalent. Based on these results, we design a purely distributed bilateration localization scheme for 3D USNs termed as (U) under bar nderwater (S) under bar ensor (P) under bar ositioning (USP). Through extensive simulations, we show that USP has the following nice features: 1) improved localization capabilities over existing 3D methods, 2) low storage and computation requirements, 3) predictable and balanced communication overhead, and 4) robustness to errors from the underwater environment.