Rapid high precision relative GPS surveying with the TI-4100

Abstract

The relative three-dimensional positions of a number of sites along a 4 km traverse were determined from combined P-code pseudo-range and dual-frequency GPS carrier phase measurements acquired in the kinematic mode. The same constellation of four GPS satellites was continuously observed at a trig-station located about 6 km from the survey area, and by a roving TI-4100 receiver mounted on a Land Rover during a time when the relative satellite-receiver geometry was good (PDOP<6). Both forward and return runs of the traverse points were made with each site being occupied for only a few seconds. The relative positions obtained for the forward and return GPS runs (repeatability) and the GPS measurements and ground-truth data (accuracy) agree to within a few centimetres for all co-ordinates. The tests demonstrate that kinematic GPS results in considerable reduction of time and cost compared with other techniques.