Aircraft laser sensing of sound velocity in water: Brillouin scattering

Abstract

This study shows that it may be feasible using state-of-the-art pulsed lasers, coupled with a novel technique for maintaining laser line stability, to design, construct, and operate an airborne laser system to remotely measure sound velocity in water. This system should be capable of yielding range-resolved (3-m bins) sound velocity in water to depths of 75 m to an accuracy of 1 m/s. Flying at aircraft speeds of 300 mi/h and operating at a laser repetition pulse rate of 10 pps, vertical sound profiles would be obtained every 44 ft. Such upper-ocean high-vertical-resolution profiles of sound speed would be useful to various Naval applications. They could serve as stand-alone data sets or combined with other real time and/or historical data sets to yield improved acoustic and oceanographic prediction models. [Work supported by NOARL.]