Spread Spectrum Techniques for Sonar Ping Technology
Navy SBIR FY2010.1


Sol No.: Navy SBIR FY2010.1
Topic No.: N101-005
Topic Title: Spread Spectrum Techniques for Sonar Ping Technology
Proposal No.: N101-005-0734
Firm: Sedna Digital Solutions, LLC
10611 Balls Ford Rd., Suite 300
Manassas, Virginia 20109
Contact: Mike Butler
Phone: (703) 530-5400
Web Site: www.sednadigital.com
Abstract: Spread spectrum signals have been successfully employed for many years in communications systems to transmit digital information when there is a need to combat the detrimental effects arising from various types of interference. More recently they have also been effectively employed in Low Probability of Intercept (LPI) and Low Probability of Identification (LPID) radar systems to minimize the impact of jamming and provide a method of hiding a signal by transmitting at low power. A spread spectrum approach for active sonar systems which requires less peak power offers the potential for improved detection performance while reducing the power requirements and the impact on marine life. We are proposing an investigation of the application of spread spectrum methods to continuously transmitted spread spectrum acoustic signals that would potentially improve active sonar detection performance by improving time-bandwidth gains and hence improve received SNR. The spread spectrum methods to be examined in this proposal will leverage previous experience with continuous active sonar technologies and significantly enhance target detection, classification and tracking processes for multi-static active ASW applications.
Benefits: The key advantages of using the proposed spread spectrum technology over existing sonar technology include lower transmitter power requirements; less impact on marine mammals; lower probability of interception and/or detection; higher SNR due to better use of time bandwidth and pulse compression; improved range and Doppler resolution; and reduced time to detect and classify. The technology can be applied to other Navy programs that have issues with high power transmissions. Two of these systems are the Low Frequency Active (LFA) transmit system and the Compact LFA system employed on SURTASS ships. Both of these systems have been subjected to some controversy due to the high power nature of their transmissions. More generally, the technology also has application to sonar systems utilized in certain commercial and marine research applications. If security concerns are addressed, there is a possibility of providing a non-militarized version of this technology for these purposes. Examples include development of low power underwater acoustic links and development of techniques for simultaneous transmission of multiple data links. Remote control underwater vehicles, sea-bed crawlers and sub-sea units could all use the technology developed from this research to utilize higher bandwidth data links simultaneously transmitting back to a base station. Autonomous underwater vehicles could use these technologies for detection and navigation. Undersea archaeologists and surveyors can send pictures to the surface using these higher bandwidth communication links. Other sub-surface monitoring devices, such as environmental, oil and gas pipeline monitoring could use these technologies as well.

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