Propagation of Uncertainties in Doppler Effect Current-Meters and Current Profilers

Doppler current-meters and current profilers are currently used in oceanography to measure and record large amount of data on ocean currents. They can be vessel-mounted or standalone, single point or profiler. Calibration techniques have been experimented, described and are employed regularly for vessel-mounted or standalone equipment’s, but the uncertainties on the currents measured by these instruments are rarely estimated. This publication proposes a method based on the supplement 2 to the “Guide to the expression of uncertainty in measurement” to fill this gap. The results of simulations made by applying this method on two instruments from the best-known manufacturers, highlight a few points concerning the speed of sound, the beam slant angles from the nominal value and the application of corrections to the heading, pitch and roll angles given by the instrument, to reduce the uncertainty on the measured velocities. The method proposed in this publication can be used to simulate the uncertainties that can be expected in different configurations and different practical applications.