A Diver-Held Synthetic Aperture Sonar

An ultra-lightweight, exceptionally small, combat hand-held diver sonar is proposed for shallow water search. The sonar provides high resolution synthetic aperture images based on diver's lateral hand motion. A transducer only few inches in size is required. Azimuth resolution of about 10 cm is expected at a range of 30 m. A set of motion compensation and scale estimation techniques developed by GORCA allow a simple sonar to produce well- focused images in the presence of severe motion irregularities due to hand motion. The diver is only required to point the transducer in the general direction of the area while performing the lateral hand motion for it to be imaged. No position measurement equipment is needed. The required information is derived from the sonar data. GORCA has an experimental sonar operating at 200 khz. The extremely simple hardware was successfully used to produce high resolution synthetic aperture images based on hand motion in the Delaware River. In Phase I, the basic concept will be verified through off-line processing of data to be collected using the existing sonar. A prototype of an operational system will be designed as well. In Phase II, the prototype will be built and demonstrated in at-sea test.