(1) Field of the Invention
The present invention relates to the field of sonar sensors and in particular to towed, active sonar arrays.
(2) Description of the Prior Art
Although passive (receiving) towable sonar arrays have become refined technology, active (transmitting) arrays, because of the requirement to position the array in an upright, vertical position, have presented certain drawbacks. Typical conventional active systems are mounted in hard, typically large, rigid towed bodies, for example, the current AN/SQS-35 tow body. The tow body is required to maintain the active array in a proper vertical orientation in order to provide the required acoustic pattern. Conventional towed active sonar systems are large, cumbersome, and require expensive handling systems that use a substantial amount of space aboard a surface combatant. Depending on the frequency of the transducers, the hard, towed bodies are quite large and difficult to handle, frequently weighing up to 4000 pounds or more. Additionally, the handling equipment needed to deploy and recover such a tow body requires considerable deck space on the aft end of the ship and this equipment presents a large radar target. The launch doors, chutes, and associated hardware also increase the radar signature of the ship. These types of handling systems impose limitations on the maneuverability of the tow vessel, prevent the covert deployment of the active array, and are unwieldly and dangerous for deployments or recoveries during high sea states. A means is needed whereby an active transducer array can be deployed from a ship in a manner similar to the deployment of passive transducer arrays, such as paying out through a hull-mounted port. The active transducer array must, nevertheless, tow in a substantially vertical position after deployment.