Abstract

This dissertation will present the concept and an algorithm for processing carrier phase measurements from satellite-based signal sources, to determine the three-dimensional (3-D) relative position between two receivers. Position accuracies on the order of 1 - 50 centimeters can be obtained depending on the number of measurements, satellite geometries, and the separation distance between the two users. The proposed algorithm is based on an extended Kalman filter, which uses satellite geometry variations, together with an accurate relative position propagation, to converge the user=s 3-D relative position down to sub-meter level within a few minutes. This converged position can serve as the initial estimate to launch a small ambiguity search, and then refine the user position to centimeter level accuracy after the ambiguities are resolved. If one of the users is at a known location, then the absolute location of the second user is found by adding the relative position vector to the known location. This is also referred to as differential positioning. The research work of this dissertation focuses mainly on the carrier phase measurements of L1 signal from the Global Positioning System (GPS) satellite.