engleski

Determination of the Gravity Field from the CHAMP Measurements Considering the Energy Integral

Gravity field determination with unprecedented resolution and accuracy is the expected outcome of the dedicated gravity satellite missions, CHAMP, GRACE and GOCE. The first of them, CHAMP, has been launched in July 2000. It is a Low-Earth Orbiter (LEO), continuously tracked by GPS satellites (High-Low Satellite-to-Satellite Tracking). Meanwhile a long set of GPS High-Low SST and accelerometer measurements is available, allowing the determination of a gravity model up to degree and order 80. In this study we have computed a CHAMP-only gravity field model using several months of measurements. For being independent of any a priori gravity information, we employ a purely kinematic CHAMP orbit. The basis of our method is the energy integral, computed from state vectors at 30 seconds sampling. In this talk we are going to present the derived CHAMP gravity field, focusing on all the related characteristics, such as (1) derivation of accurate velocities from precise kinematic orbit, and (2) the use of the accelerometer measurements, etc. Also the validation of the resulting gravity field model is discussed.

gravity field detemination; satellite missions; CHAMP; GRACE; GOCE

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