Two-hydrophone localization of a click source in the presence of refraction

This paper introduces a ray-theoretic method for fast localization of an impulsive sound source in a general stratified ocean environment by measuring relative times of direct and surface-reflected arrivals at two hydrophones. The localization problem is solved through ray tracing and wave-front tracking in the time domain. This method is computationally efficient and allows for fast, near-real time estimation of the source location, which is a significant advantage for operational localization. The accuracy of the ray-theoretic approach is compared with that of the straight-line approximation. Further, localization errors associated with the angular and temporal discretization as well as with the variability of the hydrophone depths and the sound-speed profile are addressed.