Three-tier computerized system using ambient noise to assess the performance of complex multielement sonar systems.

Abstract

Experience with both developmental and Fleet operational sonar systems suggests that it is not uncommon for a sonar to be operating far below its design performance level without the sonar operator’s knowledge that the performance is degraded. The magnitude of the degradation is often far more than an increase in gain that might be expected from a new generation improvement in that sonar. Hence, it makes sense to monitor the performance of the sonar system to detect degraded performance, to identify problems or faults when they exist, and to know when to correct the faults if it is possible to do so. Furthermore, the sonar is generally essential to an ASW mission; an assessment of its performance must be thorough and rapid. Such testing could take days, if done manually by a sonar technician. However, the task can be done more thoroughly, and in as little time as 2 or 3 min, by a smart computer program that does the analysis and decision making and uses ambient noise as the noise source. This paper discusses a three-tier comprehensive system of computer-based sonar system performance monitoring and data quality assessment algorithms. The algorithms and analysis techniques are discussed, and the results obtained on recent sea tests with vertical line arrays and towed horizontal line arrays are presented. In some cases, the sonar systems were shown to be operating at a small percentage of their theoretical or expected levels. Furthermore, if the degraded states had been known in real time, simple fixes in the field could have returned the performance of some of those systems to nearly theoretical.