COSMIC: Geodetic applications in improving earth's gravity model

The routine GPS tracking data that will be collected for the precise orbit determination of the eight COSMIC spacecraft will contain valuable information about the terrestrial gravity field. Numerical simulations based on current straw-man mission scenarios have shown: (1) For the static model of the gravity field, significant improvement is possible over our present knowledge embodied in the EGM96 model, out to harmonic degree as high as 40. (2) With respect to time-varying gravitational signals, large-scale mass transport processes in the geophysical fluids (e.g., atmosphere and oceans) can be detected or monitored during the mission, providing important global change information. Further sophisticated simulations incorporating more realistic force models will be needed once COSMIC mission scenario and spacecraft design are completely defined.