Eg&g, Inc.

Peter J Clifford

Roger L Caron

Francis R Germain

A method and apparatus for producing a linear plan view display of a seabed, employing a side scan sonar signal system, have circuitry for repeatedly determining the height of the transmitting source relative to the seabed, circuitry for sampling the returning sonar signals, and circuitry for providing from the height determination and the sampled signals, the slant range correction needed to provide a linear output display, at least in a direction normal to the direction of movement of the transmitting source. The preferred method and apparatus also have elements for determining the velocity of the transmitting source and for effecting a one-to-one aspect ratio linear plan view of the seabed topography. In other aspects of the invention, a method and apparatus for controlling the display and for implementing the mapping transformation are described.

Underwater mapping apparatus and method

A time varying gain amplifier for a side scanning sonar system having a predetermined gain versus time relationship is disclosed. The gain is substantially proportional to the square of the elapsed time measured from the last sonar pulse initiating trigger signal. The amplifier in one embodiment employs a series connection of two amplifiers, each of which has a gain which varies linearly with the elapsed time.

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Barrington, RI, United States of America

Peter J Clifford