Adapted from Phase II: The Naval Air Systems Command selected Coherent Frequency Multiplex Sonar (CFMS) as the "active" sonar Candidate (solution) for improved shallow water submarine detection. CFMS tackles shallow water ocean signal propagation difficulties head-on, exploiting signal phase coherence via an innovative real-time signal process. Phase I study results provide strong credence to the utility and effectiveness of coherent integration. The ocean's support of coherence over time intervals sufficient to achieve desired realtime processing gains, and the relative performance improvement of CFMS vs. pulse/non-coherent baseline systems are described. CFMS more than attains operational objectives of the Phase I effort. Synergistic design features result in a lower power transmissions (and reverbation) together with bandwidths tailored to "see" through apparent inhomogeneities to the p hysical scintillation limits of the ocean itself. Phase II objectives include demonstration of these two breakthrough capabilities. When proof of principle is fully established via approapriate Phase II hardware and comprehensive testing, a new era in active sonar performance, having broad significance throughout ASW, will have begun. The shallow water environment, being most complex and frustrating to current generation active sonar systems, is perhaps the ideal proving ground for the CFMS technology. A deployable CFMS active sonar for shallow water threat detection can be readily integrated into the future ASW force structure.
Keywords: ADVANCED TECHNOLOGY ACTIVE SONAR COHERENT NON-AMBIGUOUS RANGE/VELOCITY ECHOGRAPHY
