In effect, it replaces several vessel instruments with a single compact navigation package comprising a gyrocompass, GPS system and a speed log.

There are three main components in the form of sensor, control and display units.

The sensor unit contains two GPS sensors and an inertial element and is mounted on the vessel mast. The control unit contains the main CPU, serial interface and facilities for high-speed communication while its display counterpart provides for navigation data as well as control and command.

Precision heading is derived from the fixed-distance dual GPS antenna arrangement in the sensor unit, using carrier phase data to generate heading information independent of latitude and vessel dynamics;

DGPS signals can also be input to enhance position and velocity accuracy.

The inertial element provides roll, pitch and yaw and can also be used for heading determination in the event of any GPS signal loss. Meanwhile, the control unit includes up to three RS-232 and RS-422 configurable output serial lines as well an Ethernet output.

A complete system requires no scheduled maintenance or re-calibration and will retail from £10,000-£12,000, says Peter Sykes.