Water Current Velocity Measurements by a Magnetometer-Based Tilt

A novel instrument based on the tilt-drag principle is developed for measuring the instantaneous velocity of the water current. Instead to obtain the tilt by an accelerometer, a magnetometer is used. For a range of underwater velocities from 5
$cm/5$
to 50
$cm/s$
, the resolution of the instrument is 8.5 bits. The water velocity is obtained using edge computation by a microcontroller with a core based on an ARM CORTEX MO +. The error is less than a 5 % and the sensitivity 0.12 cm /
$s$
/ LS B