Harbor Security & Undersea Surveillance

Homeland Security

The current state-of-the-art in diver detection consists of a high frequency active source and a synchronized multibeam receiver.  Although these systems have proven to be effective, they introduce high energy sound waves into the water, raising environmental/ safety concerns so that many US harbors and ports will simply not allow continuous high-powered active sonar operation.  For example, the National Marine Fisheries Service (NFMS) has a duty under the Marine Mammal Protection Act to regulate those who emit noise into the ocean. The current maximum noise level that NMFS uses in their authorizations is 180dB sound pressure level (SPL).  The US Navy guidance for human divers exposed to noise is a level of 145 dB SPL.  A typical diver detection active sonar emits SPLs that exceed 190 dB.

The USSI approach is to provide a system specifically designed to address the need for a safe, environmentally friendly system to provide continuous 24-hour per day, 7-day per week detection of very quiet underwater threats such as divers, swimmer delivery vehicles, mini-subs, and autonomous underwater vehicles.

In addition, the wet end sensing portion of USSI is all-optical, there are no electronics in the water, which has been the typical failure point for the traditional systems. The sensor portion of USSI system consists of a uniform diameter, rugged, low cost sensor cable designed to be laid on or buried below the harbor bottom. 

The fiber cable can be installed on the harbor bottom or suspended from a floating protective barrier.