Efficient global gravity field determination from satellite-to-satellite tracking

By the middle of this decade, measurements from the CHAMP (CHAllenging of Minisatellite Payload) and GRACE (Gravity Recovery And Climate Experiment) gravity mapping satellite missions are expected to provide a significant improvement in our knowledge of the Earth's mean gravity field and its temporal variation.For this research, new observation equations and efficient inversion method were developed and implemented for determination of the Earth's global gravity field using satellite measurements.On the basis of the energy conservation principle, in situ (on-orbit) and along track disturbing potential and potential difference observations were computed using data from accelerometer-and GPS receiver-equipped satellites, such as CHAMP and GRACE.The efficient iterative inversion method provided the exact estimates as well as an approximate, but very accurate error variance-covariance matrix of the least squares system for both satellite missions.