Effect of different inter-satellite range on measurement precision of Earth's gravitational fie

The precision of Earth's gravitational field from GRACE up to degree and order 120 was studied for different inter-satellite ranges using the improved energy conservation principle. Our simulated result shows that:For long wavelength (L≤20) at degree 20,the cumulative geoid-height error gradually decreased with increasing range,from 0.052 cm for 110 km to 1.156 times and 1.209 times as large for 220 km and 330 km,respectively.For medium-wavelength(100≤L≤120) at degree 120,the cumulative geoid-height error decreased from 13.052 cm for 110 km,to 1.327 times and 1.970 times as large for the ranges of 220 km and 330 km,respectively; By adopting an optimal range of 220 ± 50 km,we can suppress considerably the loss of precision in the measurement of the Earth's long-wavelength and medium-wavelength gravitational field.