Torpedo defense sonar for our high value ships needs to be fast reacting to accurately detect, classify and localize targets. To accomplish this goal an active sonar is required. Sonar projector source levels need to be high to compensate for low torpedo target strength levels. These requirements lead to large and costly systems with high output levels that adversely affect mammals in the operating area and with weight, size, and drag that make towing difficult. A lower power, more compact, less expensive active sonar is needed to meet torpedo defense system objectives. Continuous Transmit (CT) active sonars are an alternative to high powered pulsed sonars. CT sonars trade-off high power pulsed transmissions for a low power continuous (i.e., 100% duty cycle) transmission. CT sonar has the ability to provide high signal-to-noise ratio at the receiver while requiring substantially lower transmitted power and correspondingly smaller transmitters than an equivalent performance pulsed sonar. The CT sonar also provides faster update rates, which results in faster and better tracking solutions. In addition to torpedo defense, the benefits of CT sonar technology have broad application to US Navy sonars.
Keywords: Torpedo Defense, Active Sonar, Continuous Transmit Sonar, Transducer, Sonar Performance Modeling, Underwater Acoustics
