DIRECT EVALUATION OF THE EARTH'S GRAVITY ANOMALY FIELD FROM ORBITAL ANALYSIS OF ARTIFICIAL EARTH SATELLITES,

The equations of motion of an artificial earth satellite are derived in terms of gravity anomalies. In practice, an adjustment using these equations should give more correct values for the gravity anomalies. To check the adjustment equations derived, a set of 184 15 degree x 15 degree equal area mean gravity anomalies, together with the coordinates of some ground stations and Keplerian elements of certain satellites were assumed correct. Satellite orbits were generated, their positions being given by topocentric right ascension, declination, and range, assuming their motion to be affected only by the earths gravitational potential. Errors were introduced into the assumed correct elements, new orbits were generated, and an adjustment was done to recover the introduced errors. Two solutions to recover the input anomaly errors were done. Author