Motion Sensors

Motion Sensors measure heave, pitch and roll – typically on surface vessels. Correcting for vessel motion is critical for multi-beam hydrographic surveys, for high accuracy acoustic positioning systems, and other applications. Most are based on three orthogonal accelerometers of which there are several types having different accuracies at different costs. Older systems, some of which are still in use, are based on pendulums.

For less dynamic or static applications, tilt sensors can be used to measure the angle of inclination. These are commonly used on subsea vehicles or instruments resting on the seafloor. Electrolytic tilt sensors use a sealed glass vial partially filled with a conductive fluid. Several metal electrodes go through the glass into the fluid filled chamber. As the sensor tilts, the surface of the fluid remains level due to gravity. The fluid is electrically conductive, and the conductivity between the two electrodes is proportional to the length of electrode immersed in the fluid. Electrically, the sensor is similar to a potentiometer, with resistance changing in proportion to tilt angle. Single and dual axis sensors are available.

For commercially available motion sensors click here.
For commercially available tilt sensors click here

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