Physical Explanation on Designing Three Axes as Different Resolution Indexes from GRACE Satellite-Borne Accelerometer

The GRACE Earth's gravitational field complete up to degree and order 120 is recovered based on the same and different three-axis resolution indexes from satellite-borne accelerometer using the improved energy conservation principle. The results show that designing X_A1(2) as low-sensitivity axis (3×10^-9 m/s²) of accelerometer and designing Y_A1(2) and Z_A1(2) as high-sensitivity axes (3×10^-10m/s²) are reasonable. The physical reason why the resolution of X_A1(2) is one order of magnitude lower than Y_A1(2) and Z_A1(2) is that non-conservative forces acting on GRACE satellites are mainly decomposed into Y_A1(2) and Z_A1(2) in the orbital plane. Since X_A1(2) is not orthogonal accurately to orbital plane during the development of accelerometer, the measurement of X_A1(2) can not be thrown off entirely, but be reduced properly