Arctic field trials of a 50 bps system have yielded ranges of more than 4km in a shallow, high multipath environment, and 8km in deeper waters. Reliability begins at the design stage. Theseus is being designed using a top-down, structured approach. The single role of under-ice cable laying drives the Vehicle Specifications, which then results in a System Specification. The AUV System can then be broken down into subsystems, or i ndividual components which are relatively self-contained.
Individual designers can then concentrate on the detailed design of each subsystem.
Good systems engineering techniques and continued communication between the designers helps ensure that the entire system operates as required. To ensure an acceptable level of reliability, the AUV system has been assigned an estimate for the probability of mission success. This figure is then used as one of many parameters in the system design. A reliability network model of the entire system is developed, which allows each subsystem to be assigned a reliability requirement. Trade-offs in reliability between subsystems are permitted, as long as the resulting reliability of the entire system stays above the requirement.