Develop and Produce High Resolution Image Processing with a MidFrequency Active Sonar

Existing mid-frequency (MP) hull-mounted active sonars can be used for high resolution imaging of submarines and small objects in shallow water (SW) by combining synthetic aperture sonar (SAS) technology with matched field processing (MFP). SAS increases the overall sonar system aperture (from the existing sonar size) to the ship's length (or longer), thereby improving the azimuthal resolution. MFP provides a means to coherently focus both target and clutter returns. Transmit waveforms, transmission parameters and the processing algorithms will be defined, and a follow-on plan for a MF-based sea test will be developed. This approach offers an economical way to significantly improve existing sonar systems because it requires strap-on signal processing hardware without modification to the sonar array. We estimate for a nominal 3 kHz MP bow-mounted sonar, SAS-MFP based resolutions of 0.15 m (6 inches) cross-range, 0.30 m (12 inches) slant-range, and 0.95 z (37 inches) depth can be achieved out to 3 km range and up to a 10 knot platform speed. This results in a two-sided mapping rate of up to 108 square kilometers per hour.