基于改进的能量守恒方法恢复CHAMP重力场模型

利用CHAMP卫星轨道和加速度计数据推求地球重力场模型的一种有效方法是能量守恒方法.本文基于能量守恒方程,推导了整体求解尺度、偏差、积分常量和位系数的计算公式,提出了整体求解位系数、积分常量、尺度和偏差参数的重力场恢复方法-改进的能量法.该方法摆脱了目前使用能量法时,必须预先通过其它外部手段标定加速度计数据以及积分常量通过近似计算获取的现状.基于德国慕尼黑技术大学(TUM)提供的约300天的CHAMP卫星几何法轨道和GFZ提供的加速度计数据,计算出了60×60阶地球重力场模型XISM-CHAMP1S,并与EIGEN-CG03C、EIGEN-CHAMP03S、EIGEN2、ENIGN1S、EGM96模型进行了比较.结果表明:XISM-CHAMP1S模型精度明显优于相同阶次EGM96、EIGEN1S和EIGEN2,与同阶次的EIGEN-CHAMP03S模型精度最为接近.

CHAMP Gravity field recovery based on the improved energy conservation approach

One of the most efficient method for gravity field determination from satellite observations of CHAMP is the energy conservation approach.In this paper,an improved energy conservation approach is presented and the corresponding formulas are derived.This method can provide an integer estimate on potential coefficients,integral constant,scale factor and bias parameter.A 60 degree and order gravitational potential model XISM-CHAMP1S is determined using about 300 days' CHAMP kinematic orbits from TUM and accelermeter data from GFZ.The comparisons among XISM-CHAMP1S,EIGEN-CG03C,EIGEN-CHAMP03S,EIGEN2,ENIGN1S and EGM96 are made.The results show that XISM-CHAMP1S model is more accurate than EGM96,EIGEN1S and EIGEN2 at the same degree and order,and has almost the same accuracy as EIGEN-CHAMP03S.