利用CHAMP卫星星历及加速度计数据推求地球重力场模型

Recoverying the Gravitational Potential Model from the Ephemerides and Accelermeter of CHAMP

讨论基于CHAMP卫星星历和加速度计数据推求地球重力场模型的数值微分算法。首先利用牛顿内插公式,根据CHAMP卫星星历观测值求解卫星运动加速度。在计算卫星加速度时,建议采用速度数据内插加速度。扣除其他非地球引力摄动加速度后,基于牛顿运动定律建立观测方程。利用GFZ数据中心提供的24天CHAMP星历数据和加速度计数据解算出50×50阶地球重力场模型,并与EGM96模型进行比较,结果表明两者在低阶位系数上有较好的一致性。

The numerical differential method based on Newton's interpolation scheme is discussed. The accelerations acting on the satellite CHAMP is derived through the numerical differential formula. It is recommended to use the velocity data for interpolating the accelerations. After the non-gravitational accelerations including the non-conservative accelerations obtained from the accelermeter and the conservative accelerations computed from models are subtracted, the observational equation is constructed based on Newton's law of motion. A 50 degree and order gravitational potential model is determined using 24 days' ephemeredes and accelermeter of CHAMP from GFZ's data center. The comparison between the satellite-only model and EGM96 is made. The result shows that they have a good agreement in the low degree and order.