On In Situ “Calibration” of Shipboard ADCPs

Abstract

Methods for in situ calibration of acoustic-Doppler current profiles (ADCPs) are considered for measurement of absolute current profiles from a moving ship. Errors are of two types: sensitivity and alignment. Least square error estimates are given for experimental determination of both factors, for use in the ?water track? or ?bottom tracking? mode. Errors in the estimation of either factor may lead to large errors in derived water velocities, although the major contributions of the two factors arise from different sources and are approximately orthogonal to one another.