Accession Number : ADD015238

Title :   Digital Bottom Mapping.

Descriptive Note : Patent, Filed 7 Dec 90, patented 31 Dec 91,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Passamante, Anthony P ; Labonski, Paul A ; Harned, Nancy J ; Hediger, Timothy B ; Ambrose, John

Report Date : 31 Dec 1991

Pagination or Media Count : 14

Abstract : Ocean bottom mapping is carried out by projecting a sonic pulse in the form of a fan-shaped beam from a vessel toward the ocean floor, receiving echoes by an array of sonic detectors extending athwartship, repeatedly taking instantaneous, simultaneous, snapshot-like samples of all the detectors in the array, and, by means of a digital computer, applying a beam-forming transform, such as a Fast Fourier Transform, to the samples, thereby producing a spectrum of amplitudes versus angles. The directions of the floor areas from which the snapshot data emanate are determined from refinement of the peaks in the spectrum of amplitudes, and the distances of the same floor areas from the vessel are determined by the time interval between the pulse and the sample. A bottom profile is constructed from the directions and distances so determined. Two alternative techniques for refining and interpreting spectrum are described.

Descriptors :   ACOUSTIC DETECTORS, AMPLITUDE, ARRAYS, BEAMS(RADIATION), BOTTOM, DETECTORS, DIGITAL COMPUTERS, DIGITAL MAPS, FLOORS, MAPPING, OCEAN BOTTOM, PROFILES, REFINING, SPECTRA, TIME INTERVALS

Subject Categories : Cartography and Aerial Photography
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE