Torus Approach in Gravity Field Determination from Simulated GOCE Observations

doi:10.11947/j.AGCS.2015.20150110

Abstract

Abstract: The principle of Torus method in Earth's gravity field determination from GOCE satellite gradiometry data is discussed. The Earth's gravity field model complete to degree and order 200 is recovered using simulated satellite gradiometry observations on a Torus grid, and the degree error RMS is smaller than 10^-16, which shows the effectiveness of Torus approach. The gravity field model is also resolved using the simulated satellite gradiometry observations given on GOCE orbits of 61 days. The influences of interpolation and polar gaps are analyzed. Without considering the low-order coefficients the geoid degree errors and cumulative errors are very small after three iterations. The maximums of them are only 0.022 mm and 0.099 mm. The white noise with PSD 5 mE/Hz^1/2 is added to the simulated observations and the gravity field model complete to degree and order 200 is also computed. The model is compared with that model which is derived using space-wise LS method and the same observations. It shows that the precision of Torus is slightly lower. Without considering the low-order coefficients the maximum geoid degree errors of Torus and space-wise LS method are 1.58 cm and 1.45 cm, and the maximum cumulative geoid errors are 6.37 cm and 5.55 cm, respectively. But the computational efficiency of Torus is greatly improved by using the two-dimensional FFT and the block-diagonal least-squares adjustment. The numerical results show that Torus method is independent and valid. Meanwhile fast resolution of gravity field based on massive amount of GOCE satellite gradiometry observations is feasible.

Key words: GOCE, earth's gravity field model, Torus method, polar gaps

CLC Number:

P223

LIU Huanling, WEN Hanjiang, XU Xinyu, ZHU Guangbin. Torus Approach in Gravity Field Determination from Simulated GOCE Observations[J]. Acta Geodaetica et Cartographica Sinica, 2015, 44(9): 965-972.

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