Institute of Geodesy Research Research Projects
Improved GPS data analysis for the Swarm constellation

Improved GPS data analysis for the Swarm constellation

Led by:  Prof. Dr.-Ing. Steffen Schön
Team:  Dipl.-Ing. Le Ren
Year:  2015
Funding:  DFG

Satellite missions are becoming more and more demanding in accuracy of the absolute and relative position and attitude of a single spacecraft or a spacecraft formation, respectively. In addition, the integrity, reliability and accuracy of the position play an important role also as scientific mission requirement. Thus, new concepts for GPS observation data quality assessment and positioning should be developed and evaluated taking advantage of variable geometries in the SWARM constellation.

The first objective is to understand the GPS data quality of the pendulum-like orbit of the SWARM formation flying through the highly active ionosphere layers. This includes the analysis of systematic and stochastic properties of the GPS observations, in particular w.r.t ionospheric impact. Subsequently, different potential noise process in the data will be identified and the observation uncertainty adequately modeled and used for the satellite positioning. The varying geometries of the SWARM constellations open up new analysis opportunities. We will take benefit to study high frequency (up to 1 Hz) ionospheric fluctuations and their impact on the spacecraft GPS receivers taking into account the results from the ionosphere-related proposals within this SPP.

A second objective is to develop and implement improved absolute and relative positioning strategies for the SWARM spacecraft formation and validate them by SLR. The obtained orbits and covariance information will be provided to IGG and used in the gravity field determination.

This Project is supported by Deutsche Forschungsgemeinschaft (DFG).