INTEGRATED GPS AND PSEUDOLITE POSITIONING FOR DEFORMATION MONITORING

The pseudolite-augmented GPS technique can overcome the limitations of GPS-only surveys in unfavourable environments, like urban areas, deep open-pit mines and valleys. However, several problems need to be solved before pseudolites can be employed in precise surveys. This paper discusses the potential use of pseudolites for deformation monitoring in unfavourable survey environments. An analysis was conducted to illustrate how pseudolite measurements can improve the strength of the positioning geometry of a hydro-power dam. The methodology for the integration of GPS and pseudolite measurements has been developed, in particular the method/strategy to calibrate the pseudolite multipath effect, one of the severe sources of errors in pseudolite measurements. A set of real GPS pseudolite observations based on a 10 x 20 in network was processed to demonstrate the usefulness of the developed methodology.