Method and Apparatus for Reducing Noise from Near Ocean Surface Sources
Patent Application, Filed 01 Oct 2001
DEPARTMENT OF THE NAVY WASHINGTON DC
Pagination or Media Count:
The present invent ion is directed to a method and system for significantly reducing the acoustic noise from near-surface sources using an array processing technique that utilizes Multiple Signal Classification MUSIC beamforming and the Lloyds Mirror interference pattern at very low frequencies. Noise from nearby near-surface sources, such as merchant ships, super tankers, fishing trawlers, seismic profiling platforms, or other sources near the ocean surface can significantly interfere with the detection and tracking of a quiet target-of-interest TOI located well below the ocean surface. The present invention reduces the noise of the near-surface sources without degrading the signal level and quality of the TOI. The present invent ion utilizes a unique application of the MUSIC beamforming process to separate the noise and signal subspace. Next, eigenvalue beamforming is used to reduce narrowband energy in selected frequency bins wherein the near-surface noise is radiating. Next, predetermined frequency and magnitude variance parameters are used to eliminate broadband noise emanating from the near-surface sources.
- Acoustic Detection and Detectors