Geoid And Gravity Anomaly Calculated By Using GRACE Data

The significance and development of Earth's gravity field, the progress of technology which is satellite detection of gravity, and the situation of three gravity satellite are described in this paper. The observation equation is established by using different methods, the advantages and disadvantages of different methods are compared, an effective method is given: preconditioned conjugate gradient method, the selection of preconditioning matrix is discussed. The fully normalized association Legendre functions'recursive algorithm and procedure are designed, and three kinds of algorithm are compared each other, the way of recursive functions is introduced. Finally, using the satellite gravity data, related conclusions are as following:1,Summarize the fully normalized association Legendre functions'recursive algorithm and procedure designed, compare three algorithm from efficiency and accuracy, and analyse the advantages and disadvantages of three algorithm.2,From the results that GCM gravity coefficient calculated the global geoid and gravity anomaly , we can see the great changes in the region clearly.3,Comparing with the calculated results of GCM and EGM96, we find that the biggest differences of the geoid and the gravity anomaly are 398.63 cm and 27.8mGal, mainly occur in the Earth's South Pole, North Pole and some regions, and analyse their reasons.4,Using GCM gravity field coefficient, we can do accuracy evaluation from two aspects:their own coefficient errors and the gravity field coefficient by download, the results calculated by own coefficient errors in degree error, every degree geoid error, geoid cumulative error of 60 degrees are 4.25×10^-10, 2.71 mm, 8.74mm, from the results calculated by the gravity field coefficient , we find that the EIGEN_GRACE02S coefficient close to it, the every degree geoid error of 60 degrees is 3.3 mm.