Heave Compensation for Hydrographic Surveying
COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS
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PURPOSE Improvements in hydrographic surveying technology, particularly depth measurement accuracy, have been supported by the Corps of Engineers. This note discusses state-of-the-art heave compensation methods as well as the development and commercial availability of heave correction equipment. INTRODUCTION Survey boat heave vertical boat movement resulting from wave action can be a major contributor to errors in depth measurements. In the past, manual or automatic smoothing of the data was the only practical way of partially correcting wave-induced errors. New techniques now give surveyors the opportunity to incorporate heave abatement equipment in their standard surveying operations and thereby produce higher quality surveys. Several approaches have been considered for measuring of alleviating heave-induced errors in hydragraphic survey of depth measurement. The most widely used approach has been to measure the survey boat motions, along with depth and position, and correct the motion-induced errors during post survey processing. A second approach has been to experiment with different hull designs for the purpose of reducing vertical boat motions ttoan acceptable level so that no corrections are necessary. A third approach is to separate the depth measurement transducer from the survey boat by using submerged, towed or remote controlled transducer platforms. For several years, the Corps has been involved in a state-of-the-art search for techniques and equipment that could be used for the abatement of heave effects in Corps hydrographic surveys. Thus far, studies of the first two approaches have been made and are discussed herein. The National Oceanic and Atmospheric Administration NOAA has been involved in a similar program. NOAA and the Corps have coordinated common evelopment paths in their respective heave study programs to avoid undesirable duplication of effort.
- Physical and Dynamic Oceanography
- Soil Mechanics