The GRACE satellite-to-satellite tracking mission will provide
measurements of the mean and time variable components of the Earth’ s gravity field
to un-precedented accuracy. These estimates wi1l provide contraints on the global
mass distribution and its time variability, which is important for a wide range of
disciplines in the Earth System Sciences. The GRACE mission will provide high
precision measurements of the range change between two low Earth orbiters using
dual-one-way, dual frequency microwave tracking. The two orbiters will be placed
in near polar, near 500 km altitude orbits, separated from each other by
approximately 250 km, over a mission lifespan of 3-5 years. The sate1llites will also
carry GPS receivers and accelerometer to aid the recovery of the gravity field from
observational data. We have performed simulation studies of expected accuracy of
gravity field recovery from GRACE in the presence of some of the prominent error
sources. Starting with a brief description of the simulation and analysis procedures,
we characterized the effects of principal measurement errors on the estimated
gravity field, along with the influence of the orbit parameters. We also obtained
results on the influence ofshort period gravity variability on the longer term
estimates of the mean gravity field.
Â