Multi-Modal Sensor for Tactical Marine Surveillance Navy SBIR FY2009.1 Sol No.: Navy SBIR FY2009.1 Topic No.: N091-019 Topic Title: Multi-Modal Sensor for Tactical Marine Surveillance Proposal No.: N091-019-0689 Firm: Information Systems Laboratories, Inc. 10070 Barnes Canyon Road San Diego, California 92121-2722 Contact: Michael Larsen Phone: (858) 373-2770 Web Site: www.islinc.com Abstract: Information Systems Laboratories, Inc. (ISL) proposes to team with Applied Physical Sciences Corp. (APS) and ERAPSCO to develop a low-cost underwater sensor capable of collecting both acoustic and electric field signals. APS is a recognized leader in the development of advanced acoustic sensors and signal processing. ERAPSCO is a joint venture of USSI and Sparton, the world''''''''''''''''s leading sonobuoy manufacturers. Exploitation of both acoustic and electromagnetic signals emitted by submarines offers new possibilities for sensor queuing and data fusion to reduce false alarms. The goal of the effort is to develop a small air deployable sensor package that can simultaneously observe the acoustic radiated signature and the electric potential signals from ships that are in the vicinity. We will develop appropriate signal and information processing algorithms to provide a robust multi-modal solution that improves initial detection performance (PD/PFA), target kinematic predictions (tracks), and target identification (target/on-target) based on features in both measurement domains. Data will be collected in Phase I to validate sensor and noise models and to make recommendations for an engineering prototype of a compact sensor package. This information will be used in Phase II to develop and test prototype a sensor with the support of ERAPSCO. Benefits: Modern diesel-electric submarines pose a threat to national maritime strategy and naval operations. The Navy no longer has the ability to conduct localization and small area search operations against quiet diesel-electric submarines using passive sensing methods. Acoustic quieting and background noise levels in the littoral have decreased the detection range of these submarines to the extent that maritime patrol aircraft stores of passive "A"-size buoys (AN/SSQ 53F/77C family) are no longer adequate to meet the time and search area requirements for these missions. Detection ranges of passive sensors against quiet acoustic signals cannot be improved without considerable technical risk and increased buoy cost and size. Active acoustic sensor use in the littoral suffers reverberation range degradation and alerts the submarine, enabling it to undertake stealth and threatening countermeasures. Passive acoustic sensor detection range is severely limited in the littoral due to reduced threat sound pressure levels and intense background noise. Complementary sensing modalities are needed to augment acoustic sensing in order maintain an effective ASW capability for Maritime Shield, Clean Sweep, and Hold-At-Risk Naval operations. One way to improve the performance of acoustic sensor systems is to conduct data fusion with information collected from other sensors. Electric field (E-field) sensors show great promise for performance enhancement through fusion with acoustic signals. In littoral ocean environments, passive acoustic systems have limited operating range due to bathymetric occlusion and heavy shipping noise. In addition, the large number of surface ships can create a situation where operators cannot separate the acoustic signals associated with multiple sources. Under these conditions, the additional modality of e-field sensing can provide significant advantages by cueing the acoustic sensor when a ship is in proximity of the sensor location, providing independent measurements of kinematic features of a nearby contact (bearing, bearing rate and time of closest point of approach), providing ELFE measurements which can be use to predict acoustic observables (i.e. blade rate), and adding additional independent observable features that can be used to aid in the identification of a nearby ships as targets of interest or clutter. Return