Hardware-in-the-loop simulation for undersea vehicle applications

Torpedoes and other Unmanned Undersea Vehicles (UUV) are employed by submarines and surface combatants, as well as aircraft, for undersea warfare. These vehicles are autonomous devices whose guidance systems rival the complexity of the most sophisticated air combat missiles. The tactical environment for undersea warfare is a difficult one in terms of target detection, classification, and pursuit because of the physics of underwater sound. Both Hardware-In-the-Loop (HWIL) and all-digital simulations have become vital tools in developing and evaluating undersea weapon and vehicle guidance performance in the undersea environment. Accurate modeling of the underwater acoustic environment, including the ocean medium and targets, presents the major challenge to the development of HWIL simulations. This paper discusses general torpedo operational theory and describes that undersea warfare environment relative to the development of viable simulations. The Undersea Weapon Evaluation Facility (UWEF), one of two HWIL simulators within the Naval Undersea Warfare Center, has been developed for land-based captive testing of torpedoes and other UUV operating under their own power in a water-filled test chamber while dynamic and acoustic simulations provide closed-loop stimulation to the Unit Under Test (UUT). Development challenges and operational attributes of UWEF are discussed.