System for Optimization of Very Low Frequency Audio Signals

"Very low frequency (VLF) sonar signals are advantageous because target detection and tracking can occur at very large distances. Visual displays which transform the time-domain signals into the frequency domain and which average over time are currentlyused for target detection and tracking. However, averaging can mask important information about transients and other ocean acoustic events. Further, sonar operators do not listen to VLF signals because current hardware and signal processing techniquesare not effective in this frequency range.Creare proposes to complete the development of a system to optimize VLF audio signals for human operator hearing. The system will enable frequency translation and compensation so that the signal can be calibrated to the hearing response of a specificsonar operator and will enhance transients. In addition, we will provide a user interface for optimally presenting VLF acoustic signals to sonar operators.During Phase I, we conclusively proved the feasibility of our innovation by developing a bench top system and demonstrating the system using synthetic and recorded acoustic signals. In Phase II, we will complete the system development by optimizing thesystem using real-world data, performing testing with a sonar processing string, and preparing for sea trials.BENEFITS: This technology has the potential to significantly improve the ability of sonar operators to perform target detection and classif