Overcoming Environmental Limitations on Active Sonar Detection Performance

Inverse Beamforming (IBF) active acoustic processing and analysis concepts are presented to identify the environmental acoustic parameters that degrade active acoustic sonar performance in shallow water due to time dependent multipath arrivals. A fully coupled normal mode model is proposed to be used with measured data to identify environmental parameters that adversely impact active sonar performance due to time dependent multipath arrivals. An example of shallow water multipath dispersion is described using active acoustic sonobuoy data in shallow water. IBF active acoustic energy detection and signal replica correlation algorithms and methods of using IBF to enhance active sonar system performance are described. An IBF synthetic aperature technique is presented that is based on IBF matched field processing (IBF/MFP). Higher spatial resolution will be achieved when IBF is used over synthetic apertures.