Bearing estimation error analysis using laser acoustic sensor measurements on a hydrodynamic surface

The basic operation of a novel laser-based sensor is investigated. A low power laser beam emanating from a laser Doppler velocimeter is used to interrogate an air-water interface for underwater sound detection. The sensor measures the normal velocity of the vibrations of the pressure release air-water interface. The objective of this paper is to discuss the feasibility and fundamental limitations on using the laser-based acoustic field velocity measurements of hydrodynamic air-water interface to determine acoustic field direction of arrival. This paper identifies the various contributions to bearing uncertainty using the Cramer-Rao lower bounds to establish the limitations of determining the bearing of the in-water sound.