基于矩谐分析的航空重力向下延拓

Downward Continuation of Airborne Gravity Data Based on Rectangular Harmonic Analysis

提出基于矩谐分析的航空重力向下延拓方法,以重力扰动作为基本观测值,给出基于矩谐分析的向下延拓模型和算法。利用EGM2008重力位模型设计模拟数值试验,对比研究矩谐分析、直接法和基于广义岭估计的逆泊松积分法,分别采用这3种方法将飞行高度处含高斯白噪声的2.5′×2.5′重力扰动向下延拓至大地水准面,与真实值作外部检验。数值比较结果表明:矩谐分析在延拓精度、稳定性和边界效应等方面都要优于直接法和基于广义岭估计的逆泊松积分法,能取得良好的向下延拓效果。

Rectangular harmonic analysis （RHA） is proposed for the downward continuation （DWC） of airborne gravity data, with the mathematical model and detailed algorithm presented. By conducting a simulated numerical experiment based on EGM2008 Earth gravitational model, three DWC approaches： RHA, direct method and inverse Poissen integral method based on generalized ridge estimate are compared and studied. The 2. 5＇× 2. 5＇ gravity disturbances with Gauss white noise at the flight levels are downward continued to the Geoid and compared with the true values. The numerical results show that RHA performs better than direct method or inverse Poisson integral method based on generalized ridge estimate.