Initial Orbit Determination Results for Jason-1: Towards a 1 cm Orbit

The U.S./French Jason-1 oceanographic mission is carrying state-of-the-art radiometric tracking systems (GPS and DORIS) to support precise orbit determination (POD) requirements. The performance of the systems is strongly reflected in the early POD results. Results of both internal and external (e.g., satellite laser ranging) comparisons indicate that the root-mean-square (RMS) radial accuracy is in the range of 1–2 cm. This paper reviews the POD strategy underlying these orbits, as well as the challenging issues that bear on the understanding and characterization of an orbit solution at the 1 cm level. It also describes a GPS-based system for producing science-quality orbits in near real time to support emerging applications in operational oceanography.