Perturbing sound speed field estimates to study quality of acoustic ranging

Abstract

Acoustic ranging is clearly dependent on the sound speed field c(x,y,z), where the points (x,y,z) are constrained to the two-dimensional region defined by a submerged source at a certain point in the ocean and a submerged receiver at a different but unknown point in the ocean. An in-situ estimate of c(x,y,z) based solely on a sound speed profile taken at the source of known location and one taken at the receiver at a unknown location has been used to obtain reasonable ranging estimates over large source-receiver separation [Sarma etal., IEEE UASP (2019)]. We discuss an approach to perturb this estimate of c(x,y,z) in a physically sound manner consistent with internal wave and other ocean processes in order to study the effect on the accuracy of ranging methods. The approach can indeed be applied to any estimate of c(x,y,z). The ultimate motivation for this work is in-situ determination of the inherent variability expected for a specific range estimate from any range estimation technique.