The principal type of exercise conducted on the undersea warfare training range (USWTR) would be antisubmarine warfare training (ASW). Submarines, surface ships, and aircraft all conduct ASW and would be the principal users of the range. Either individually or as a coordinated force, submarines, surface ships, and aircraft conduct ASW against submarine targets that include both actual submarines and other mobile targets that simulate the operations of an actual submarine. ASW exercises are complex and highly variable. The Navy plans to train throughout the year (running the exercise scenarios a finite number of times per year), with events evenly distributed across all four seasons.

The requirements for realistic conditions on the USWTR necessitate training with a variety of sensors, non-explosive exercise weapons, target submarine simulators, and other associated hardware. Many of the materials used on the USWTR would be recovered after use; however, some would be left in place. All ordnance used would be non-explosive.

Tactical military sonars are designed to search for, detect, localize, classify, and track submarines. There are two types of sonars, passive and active, and both will be used in exercises on the USWTR.

• Passive sonars listen to incoming sounds and do not emit sound energy in the water. Because of this, passive sonars lack the potential to acoustically affect the environment.

• Active sonars generate and emit acoustic energy specifically for the purpose of obtaining information concerning a distant object from the reflected sound energy that is received and processed. Active sonars are the most effective detection systems against modern, ultra-quiet submarines in shallow water.

Modern sonar technology has developed a multitude of sonar sensor and processing systems. In concept, the simplest active sonars emit omni-directional pulses (“pings”) and time the arrival of the reflected echoes from the target object to determine range. More sophisticated active sonar emits an omni-directional ping and then rapidly scans a steered receiving beam to provide directional, as well as range, information. More advanced sonars use multiple preformed beams, listening to echoes from several directions simultaneously and providing efficient detection of both direction and range.

The tactical military sonars to be deployed in the USWTR are designed to detect submarines in tactical operational scenarios. This task requires the use of the sonar mid-frequency (MF) range (1 to 10 kHz) predominantly.

ASW training targets that are used to simulate target submarines are equipped with one or a combination of the following devices:

• Acoustic projectors emanating sounds to simulate submarine acoustic signatures.

• Echo repeaters to simulate the characteristics of the echo of a particular sonar signal reflected from a specific type of submarine.

• Magnetic sources to trigger magnetic detectors. Both expendable and recoverable training targets would be used on the USWTR.

Other active acoustic devices used on the USWTR would be range pingers, which allow the range transducer nodes to passively track each of the in-water platforms on the range (e.g., ships, submarines, target simulators, and exercise torpedoes ). In addition, the range transducer nodes are capable of transmitting acoustic signals for a limited set of functions that include submarine warning signals, acoustic commands to submarine target simulators (acoustic command link), and occasional voice or data communications (received by participating ships and submarines on range).

The USWTR would take advantage of existing logistics support for range operations, with some additional logistical support arrangements to accommodate the delivery and recovery of targets and torpedoes. Recoverable targets are recovered completely and would be provided to the range by a range support boat. Rotary-wing aircraft not operating from ships would require a minimal staging area to onload/offload and potentially store torpedoes, depending on how often they are used on the range. When a heavyweight exercise torpedo is recovered, the exercise torpedo is returned to the range support facility before transport back to an intermediate maintenance facility to be rebuilt for reuse.