SBIR-STTR Award

Currently an effective diver mine imaging sensor for use in VSW mine reconnaissance does not exist. The SBIR topic requests a capability to locate and image mine targets within a 45 deg wide x 10 deg high field-of-view and to image targets with a resolution of at least 3" at a range of 20 yards. An acoustic lens sonar is a preferred technical approach. Both an acoustic lens sonar and a more compact, lower cost diver imaging system will be investigated. This alternative imaging system employs a low resolution, mine detection sonar coupled with a very high resolution lidar to image and identify targets at ranges out to 20 yards. Phase I will consists of: (1) mine detection and imaging system trade studies, (2) design of a high resolution imaging sensor system, and (3) the conduct of a series of critical component demonstrations of breadboard subsystem components in order to reduce the risk of prototyping an imaging system during Phase II. The detection sonar proposed for this system has detected a -20 dB sonar target at a range of 88 yards, on a sand bottom in 20 feet of seawater. Lidar imaging performance is predicted at 5 attenuation lengths in 4 meter attenuation length water.

This research will provide a capability for divers to conduct mine and obstacle reconnaissance of shallow water and very shallow water areas with an integrated sensor and navigation system which combines high resolution sonar a 5 ns range-gated lidar, GPS and the SEAL Inshore Navigation System (SINS), and Global Positioning System (GPS) receivers. This integrated sensor-navigator system provides the diver a capability to detect -20 db bottom targets at ranges out to 90 meters, classify targets at 20 meters and relocate targets within 2 meters of the SINS acoustic navigation system reference and correlate these positions with GPS coordinates. Two prototype systems are proposed to be developed and tested. Each will weigh approximately 16 kg in air, be neutrally buoyant in sea water and have 4 hours endurance. Prototypes will demonstrate fusion of sensor data and its presentation to the diver on a flat paned display and an audio channel. Sensor and navigation in formation will be recorded for post mission processing and analysis. Options to integrate an Aural Detection Sonar and/or a Fluxgate Gradiometer into the Diver Sonar-Lidar/Navigator sensor suite are also proposed. Their adoption would facilitate target classification in turbid water and could provide an ability to detect and classify buried magnetic mine-like targets. Enhanced capabilities provided by this system allow divers to accomplish mine reconnaissance missions mor safely, reliably and rapidly. As such this research provides a force multiplier in Very Shallow Water Mine Countermeasures.

Keywords:
MINES, SONAR, LIDAR, GPS, MINE COUNTERMEASURES, MAGNETIC SENSOR, AURAL CLASSIFICATION ACOUSTIC NAVIA