Accession Number : ADD005694

Title :   Correction and Transmission System for Directional Target Information.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Bates,Albert M ; Sandford,Wayne H , Jr ; Madera,Anthony J

Report Date : 22 Aug 1978

Pagination or Media Count : 9

Abstract : An object detection system capable of receiving and processing an omnidirectional signal and two directional signals to produce a digitized omnidirectional signal, and digitized directional signals which have been corrected to magnetic north. The directional hydrophones produce sin theta and cos theta signals, where theta is the bearing angle of the sensed target from the directional hydrophones' y-axis. Each of the three signals is picked up by a separate hydrophone and is passed through an associated preamplifier and a shaper amplifier and low pass filter before being simultaneously sampled by separate sample/hold circuits. The three sampled signals are multiplexed to an analog to digital converter. The signal produced by a digital magnetic compass is converted to sin theta and cos theta values by appropriate function generators, where theta is the angle between the y-axis and magnetic north. The digital sin theta, cos theta sin phi and cos phi signals are the multiplied together in a multiplier and the products placed in separate registers and added or subtracted by an adder to produce directional signals corrected to magnetic north according to the formulas sin theta cos phi - cos theta sin phi = sin (theta - phi) and cos theta cos theta + sin theta sin phi = cos (theta - phi). The corrected directional signals are then multiplexed together with the omnidirectional signal and a synchronization word and passed through an encoder to a transmitter for transmission to a distant receiver for processing and analysis. (Author)

Descriptors :   *Patents, *Acoustic detectors, *Hydrophones, *Signal processing, Digital systems, Omnidirectional, Targets, Acoustic signals

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE