A comparison of DGPS correction sources in South Eastern Queensland

Abstract

Differential Global Positioning Systems (DGPS) correction sources available in south eastern Queensland vary substantially in price, precision and accuracy. These factors were compared for the three most widely accessible real time DGPS correction sources: Virtual Reference Station (VRS) DGPS, OmniSTAR and Australian Maritime Safety Authority (AMSA) Beacon. In addition, a similar analysis was accomplished for a selection of four post processed DGPS correction sources including three stationary reference points and one modelled reference point. Dynamic and static measurements were taken for all of these systems at 17 sites across south eastern Queensland, spanning approximately 6,000 km2. Statistical analysis of the mean and variance of these results illustrated that regardless of cost, all post processed DPGS correction sources were of similar accuracy and precision. Real time correction sources varied in their accuracy, but not their precision, with the most expensive correction source, VRS DGPS, clearly the most accurate. However, if a bias correction is applied to AMSA Beacon and OmniSTAR DGPS correction sources similar accuracies may be obtained. Within this test area, the distance from the origin of the correction source of each system had little impact on the result. For the first time in south eastern Queensland, this illustrates that less expensive correction sources, if appropriately corrected, produce results as accurate and precise as those from expensive sources.