Preliminary Results of the Carrier-Smoothed Code- Phase Differential GPS/Pseudolite System

With the full GPS operational capability in the mid-1990s, it has been used as a stand-alone system for many land applications that require fast and precise positioning such as mining, heavy construction, precision farming, and automated highway systems as well as in other high-traffic land-based applications. However, there are situations where GPS by itself does not provide the desired accuracy, for example when satellite signals are blocked or when the achievable accuracy is restricted by the geometry of the satellite constellation. In these situations, augmentation of GPS using ground-based GPS transmitters, pseudolites can be used to enhance the availability, accuracy, and reliability of the GPS-derived position solution. This research builds on the current work between the SNAP (Satellite Navigation And Positioning) group at The University of New South Wales, Sydney, and the DSO National Laboratories, Singapore. They are jointly developing a local area augmentation system able to provide high accuracy navigation for aircraft approach and landing. The first phase of this autolanding system development consists of a carrier-smoothed code-phase differential GPS/pseudolite technique to determine the feasibility of a robust differential GPS/PL technique for aircraft precision approach and landing. This paper assesses the performance of the carrier-smoothed code-phase differential GPS/pseudolite algorithm to be used for land applications. Preliminary post-processed results are presented and analysed of vehicle trials at La Perouse and Coogee, Australia.