dGPS & WAdGPS

When a known position is used to obtain a unknown position utilising the same satellites.

• The base station will continually calculate the range to each satellite it can see & compare that range to the Pseudo-Range received.
• It will compare the 2 and determine a Pseudo-Range Correction for each satellite.

The PRC is passed to the ship by the radio wave link.

Has an accuracy to +/-5m

Is a form of dGPS where corrections are received from a network of reference stations established over a wide area.

This bring the accuracy down to +/-3m

The corrections are calculated at a central uplink station and are sent to the unit by means of geostationary satellite.

Provides a position solution using the 5 nearest base stations

Receives the GPS signal via a Trimble Antenna

Receives the PRC via a second Antenna

PRC is then processed

Correct position output to the Online System

IOWIN- serial input & output of data

MRdGPS- multi-reference dGPS. Shows all QC data related to selected base station

QCPLOT- monitoring various outputs

ALARM- Issues alarms and warnings