Maritime defence forces that deploy modern sonar systems against targets that are becoming more difficult to detect, are faced with several problems including how to maintain sonar operator and command team effectiveness at sea; how to train ASW teams onboard ships, submarines, maritime patrol aircraft and helicopters; how to confirm that complex ASW systems assess, classify and operate correctly against threat signatures; how to confirm that sonar systems continue to operate at optimum performance without degradation; and how to confirm that new equipments/refitted equipments meet their performance specifications.
These complicated issues must be addressed if maritime defence forces are to maintain their ASW capabilities.
Modern defence forces require a continuous level of training to ensure that sonar operators retain their detection skills and in ideal conditions they would be trained using live submarine targets. However, training with a navy's own submarines provides a friendly target whose signature soon becomes recognisable. This does not prepare operator teams for the unexpected, nor do they become familiar with the generation of firing solutions on threat signatures. To solve these problems there are many sonar targets available that comprise self-propelled, battery-powered targets; towed targets; transponders; submarine-mounted augmentation equipments; and submarine-launched targets.
| Gearing & Watson's sonar test source |
A major problem with most targets is that their operating periods are limited to a few hours by their expensive batteries. They are then recovered or allowed to sink. Such targets also have limited ability to drive transducers that generate the very low frequencies associated with submarine signatures.
It is important that sonar operators experience long periods of training to ensure they are exposed to long periods of working in a watch system that includes extended periods of inactivity and the opportunity to detect and track many types of submarine target.
These requirements are met by towed-target systems better than any other type of simulated target because they may be deployed for indefinite periods and programmed to represent any number of target types. They may be used to provide echo repeat and transponder capabilities to exercise active sonars where sonar transmissions received by the target may be manipulated to provide doppler shift, response delays and target-strength variations, and they may be used to provide periodical events such as transients. But they should be deployed at speeds below the cavitation speed of the towing vessel that otherwise may be detected more easily than the target. However, their many advantages include being deployed by tugs or trawlers; very wide frequency bandwidths may be used with operating frequencies ranging from 30Hz to 100kHz; high powers may be generated; the operator may modify operating frequencies and levels at any time without recovering the target that may be used in all weather conditions and deployed for indefinite periods.
Gearing & Watson produces a family of towed, static and submarine mounted target systems known as Subtrack.
