The Computations of Near Real-time GNSS Precise Orbit and High-Rate Clock
Zhang, Q¹; Moore, P¹; Hanley, J²; Martin, S^2
1Newcastle University; ²LogicaCMG

The Auto-BAHN software producing accurate near real-time GNSS orbits and high-rate clocks has been developed at Newcastle University. Efforts to date have resulted in version 1, a prototype for a fully operational system. Auto-BAHN version 1 consists of four modules: the Data Collection and Pre-processing Module, the Orbit Module, the Clock Module, and the Informatics Module. For the Orbit Module, an Extended Kalman Filter has been developed to process low-rate GPS data and facilitate continuous computation of near real-time orbits and clocks for GPS satellites and other receiver and satellite parameters. The near real-time products, namely orbits and zenith atmospheric delays, from the Orbit Module, are input into the Clock Module in which high-rate data (e.g. 1-Hz) can be processed to produce precise high-rate satellite clocks. In this paper, results obtained to date from the development of Auto-BAHN version 1 are presented. The accuracies for GPS orbits and clocks achieved with the Orbit Module and the Clock Module are illustrated through comparisons with IGS final solutions and JPL solutions.