Cynthia B. Straney
Michael J. Forbes
Naval Undersea Warfare Ctr. Div. Newport, Code 8213, Newport, RI 02841
The transmit--receive response of an active sonar system measuring volume reverberation is numerically calculated as a sum of time-delayed, phase-shifted replicas of the transmitted signal. The sonar system can consist of any combination of projectors and hydrophones. The scattering volume of interest is modeled as a distribution of cylindrical and spherical scatterers of different maximum target strengths. The propagation path between projector and scatterer and scatterer and receiver is assumed to be a straight line. Temperature and density fluctuations are modeled as sound-speed changes along the propagation path and spreading and absorption are included. The sonar system and each of the scatterers in the volume are allowed to move continuously, both translationally and rotationally. Output consists of raw amplitude data received by the hydrophone(s) at a predetermined sampling rate. Calculated results are in excellent agreement with experimentally measured scattering values from a collection of hard spheres. [Work supported by ONR.]