Underwater Acoustic Communications Navy STTR FY2005 Sol No.: Navy STTR FY2005 Topic No.: N05-T022 Topic Title: Underwater Acoustic Communications Proposal No.: N054-022-0224 Firm: EdgeOne DBA EdgeTech or ORE Offshore EdgeTech 1141 Holland Drive Boca Raton, Florida 33487 Contact: John Spruance Phone: (561) 995-7767 Web Site: www.ore.com and www.edgetech.com Abstract: This proposal addresses the development of an improved algorithm for estimating the time-varying impulse response of the ocean in rapidly fluctuating environments, and the development of the means to exploit the temporal diversity of acoustic channels. The short-term objective is the initial design and testing of this technique using direct-sequence spread-spectrum modulation, high-resolution decision feedback equalizing with parallel tracking of large Doppler, based on the methodology developed at FAU by Pr. Beaujean. The long-term objective of this program is the development, testing and commercialization of a high-speed high-frequency acoustic modem (HS-HFAM) capable of transmitting data at true rates of up to 105,000 bits per second (bps), at a maximum range of 500 meters. This modem would operate between 240 kHz and 360 kHz approximately, and achieve a peak range-to-true rate in excess of 50 kbps-km. Benefits: AUV technology has found new applications in the field of hull survey and port security, and remains a key feature of mine counter-measure operations. Some AUVs are now capable of hovering around a target or the hull of a ship and record high-definition sonar images. The image quality is sufficient to visually identify potential threats, such as divers, mines or weapons of mass destruction. The AUV can operate while keeping key personnel at a safe distance from a potentially dangerous device, typically a few hundreds of meters away from the point of deployment. Having human-in-the-loop capability is essential during this type of operation, and requires the transmission of images to a remote user. Today, this high-bandwidth information is transmitted by cable, which limits the AUV maneuverability, causes drag, increases the chances of entanglement and prevents the AUV from operating in confined areas, near propellers and around pilings. When combined with the latest technology of data compression, the proposed broadband acoustic modem could transmit the same high-resolution images in compressed format while the hovering AUV performs its mission without risk of entanglement. In addition to the military needs associated with transmission of underwater images there are also other commercial applications, both AUV and non-AUV related. Pipeline inspection work and integrating the modem into a hull monitoring system in ports and harbors for homeland security are two readily identifiable ones. Return