ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

2pUW11. Effects of scattering-induced frequency spread on Doppler performance.

Anthony I. Eller

Ellen M. Daley

Appl. Ocean Sciences Operations, SAIC, 1710 Goodridge Dr., McLean, VA 22102

Frequency spreading caused by forward scatter from a dynamic rough surface will degrade the performance of active acoustic systems that are attempting to identify slowly moving targets against a reverberation background. This paper addresses the sequence of calculations and the approximations made to the governing physics in a system performance model whose primary output is a measure of target detectability at all locations in a two-dimensonal grid. The relative frequency spreading resulting from system geometries and motion, active waveform shaping, and boundary interactions are compared and are related to Doppler detection performance as a function of environmental conditions. The received reverberation is characterized by the Q function, which is then convolved with an eivironmental spreading kernel based on the surface wave power spectral density. The scattering angles and frequency of boundary interaction are determined by shallow water propagation codes.