The introduction of multi-beam echosounders some 20 years ago has placed an ever-increasing focus on the need for accurate attitude data. This event has since motivated engineers to produce highly accurate motion sensing systems for the hydrographic industry.

Manufacturers have developed different types of systems based on their background. Coda Octopus and Applanix LLC have introduced a GPS-aided inertial navigation system utilising accurate positioning and motion sensor technology in one system. IXSEA use fibre-optic gyro (FOG) technology in their systems. A FOG is a gyrometer, which is a sensor that instantaneously measures the rotational speed of a mobile platform. The FOG is based on the Sagnac effect, discovered in 1917 by a physicist named Georges Sagnac. Other manufacturers use solid-state gyros and accelerometers and micro-electromechanical system (MEMS) sensor technology using the highest quality MEMS accelerometers, gyroscopes and magnetometers available for a robust and precise orientation reference system.

Most manufacturers provide a wide range of systems, each serving its specific need. An example is Kongsberg Seatex, with eight different models. Due to the volume of the product ranges, we are unfortunately unable to present all the available systems. We have therefore limited this Product Survey to the most commonly used and recent systems, using the documentation of manufacturers who sent us the information.

Driven by industry needs for deeper, faster and more accurate positioning, we expect the development to continue to further change the way hydrographic data are collected and processed.

We are again grateful to all the manufacturers who contributed to this Product Survey and the many in-depth questions about their products.