Optimal Seafloor Mapping Technologies Navy SBIR FY2009.1 Sol No.: Navy SBIR FY2009.1 Topic No.: N091-088 Topic Title: Optimal Seafloor Mapping Technologies Proposal No.: N091-088-1343 Firm: Heat, Light, and Sound Research, Inc. 3366 N. Torrey Pines Court Suite 310 La Jolla, California 92037 Contact: Christian Moustier Phone: (858) 457-0800 Web Site: http://www.hlsresearch.com/ Abstract: The primary objective of this proposal is to implement an autonomous swath bathymetry survey capability aboard an unmanned undersea vehicle (UUV) using a hybrid sonar that combines the high spatial resolution of a focused multibeam echo-sounder in a �30� sector about nadir with the long-range focusing capability of a bathymetric sidescan sonar (Fig. 1) for a total swath angle in excess of 160� (swath width roughly 11 times the UUV's altitude above the bottom). This represents a better than twofold improvement in swath coverage (hence survey efficiency) over existing solutions that rely on a multibeam sonar system alone, and it fills the near-nadir data gap typical of systems that rely on a bathymetric sidescan sonar alone. In both sonars, dynamic focusing will help constrain the vertical uncertainty associated with each sounding. Likewise, high across-track data density for each ping will provide the redundancy necessary to constrain horizontal uncertainties. For each ping, the achieved swath coverage wlll be defined at the across-track limits where sounding uncertainty exceeds a prescribed threshold. The ping-to-ping evolution of these limits along-track, and the corresponding bottom topography, will be used to estimate the lateral offset of adjacent swaths that minimizes redundancy while maintaining 100% bottom coverage. This method will work best if the UUV maintains a nearly constant altitude above the bottom. Benefits: The proposed hybrid system would be immediately useful to hydrographic surveyors for shallow water (0-40 m) mapping applications with hull-mounted transducers. Installed aboard a UUV, the proposed hybrid sonar would satisfy survey requirements in water depth to 200 m (the edge of the continental shelf) with existing hardware. Transducers and electronic pressure cases with deeper depth capabilities are possible upgrades for operations at depths in excess of 200 m. Return