Precise navigation solutions integrating GPS and low-cost inertial navigation technology have been developed in the last decades to optimise accuracy in the offshore and hydrographic industry. This technology is well known and established in the market.

Solutions are also available that provide precise measurements of heading, position, velocity, pitch and roll from GPS only, without the integration of an accurate inertial system. These systems have found their way in the industry where extremely accurate attitude, heading, heave position and velocity are not required.

GPS compasses provides true heading with no moving parts, considerably reducing the requirement for servicing. The GPS compass may not only replace the traditional gyrocompass but may also

replace several other vessel instruments such as positioning system and speed log.

Since the system comprises two GPS receivers, it also provides position redundancy. Some of the systems are built into one compact package. Systems using separate GPS antennas provide the possibility of placing antennas at longer distances, optimising the heading accuracy. The Hemisphere products have heading aiding by means of an internal fluxgate compass. Trimble integrate GLONASS signals to provide a degree of redundancy in the position and heading calculation, optimising use in the higher latitudes. The quoted positive answer to the question whether the system is prepared for Galileo may be questionable and unknown to what level the system is prepared for Galileo, since Galileo ICD and licensing has not been issued yet. However, in the future, the receivers will undoubtedly support the Galileo system.

Hydro international is indebted to all the manufacturers who contributed to this Product Survey. Of course, not all available systems on the market are presented here, and we encourage manufacturers to present these systems in the next relevant product survey.