### ASA 124th Meeting New Orleans 1992 October

## 5aUW14. Numerical model of the transmit--receive response of an active
sonar.

**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.]