Multi-constellation satellite navigation : precise orbit determination and point positioning

Abstract

Satellite positioning is evolving rapidly. Thanks to the deployment of new Global Navigation Satellite Systems (GNSS), such as Galileo or BeiDou, as well as the modernization programmes for the traditional systems, such as GPS and Glonass, navigation users can use today as many satellites and signals as never before. Satellite navigation is therefore evolving from dual-frequency GPS and Glonass to a multi-frequency multi-GNSS scenario. The optimal use of all new signals and systems for precise geodetic applications is an on-going research task. In particular, this thesis focuses on the Precise Point Positioning (PPP) technique, which makes use of precise satellite orbits and clocks for GNSS satellites to obtain centimeter-level absolute positioning. Thanks to the precise products delivered by the International GNSS Service (IGS), the technique has been widely used since its introduction in the late nineties, initially for GPS and later also for Glonass.