OMNISTAR

System Overview

The NAVSTAR Global Positioning System (GPS) is a satellite positioning system developed and operated by the United States Department of Defence. The world has free access to this GPS service; however the accuracy has been downgraded so that user can only expect to be within 100 metres of the true position 95% of the time using single GPS receiver.

In order to the inadequate accuracy, differential GPS is applied (DGPS) to improve their accuracy. Fugro has setup a worldwide system of GPS reference stations. Differential correction are transmitted every second from all reference station to the Network Control Centre (NCC) at Perth, Western Australia, which operates 24 hours a day, 365 days a year. These corrections are uploaded to a communication satellite, which transmits the corrections to LGBX GPS Receiver in a standard correction format (RTCM). The system network reference stations are able to give an accuracy of 1 – 2 metres .