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Articles

1989: Vol. LXVI No. 2

National Oceanic and Atmospheric Administration Sea Beam System 'Patch Test'

Submitted
July 31, 2015
Published
2015-05-14

Abstract

A procedure, commonly referred to as a ‘Patch Test’, has been developed by the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) to obtain correctors for Sea Beam system pointing errors and to verify system performance. The procedures described in this paper measure the biases associated with the fore and aft steering of the acoustic projector beam (pitch bias), the athwartship alignment of the received beams (roll bias), and the misalignment of the gyrocompass relative to the projector and receiver arrays (swath alignment bias). In addition, the repeatability of selected individual beams and the overalll system is determined. Verifying system performance before commencing survey operations is especially important with muiti-beam sonar systems. Because of the depths in which they are operated, pointing and alignment biases can introduce significant systematic errors in both depth find position of multi-beam soundings. Development of this procedure is a combined effort between NOS’s Office of Marine Operations and Ocean Mapping Section (OMS). The procedure was developed for General Instrument Corporation (G1C) Sea Beam swath sonar systems configured to integrate sonar, navigation, and gyrocompass data into the data acquisition system and produce single-swath contour plots from the onboard data processing system. The general procedure is also applicable to the new NOS Intermediate Depth Swath Survey System currently under development, and other swath sonar systems capable of creating single-swath contour plots.