联合使用位模型和地形信息的陆区航空重力向下延拓方法

Downward Continuation of Airborne Gravimetry on Land Using Geopotential Model and Terrain Information

为了规避传统逆Poisson积分向下延拓解算过程的不适定性问题,借鉴导航定位中的"差分"概念,利用超高阶位模型直接计算海域航空重力测量向下延拓改正数的方法。本文在此基础上提出联合使用重力位模型和地形高数据,计算陆部航空重力向下延拓总改正数的改进方案,以飞行高度面与地面对应点的位模型差分信息表征总改正数的中长波分量,以相对应的局部地形改正差分修正量表征总改正数的中高频成分,从而实现航空重力数据点对点向地面的全频段延拓。在地形变化不同区域,联合使用EGM2008位模型、地面实测重力和高分辨率高程数据进行了实际数值计算和精度评估,验证了该方法的有效性。

In order to evade the ill‐posedness of downward continuation for airborne gravity data using traditional inverse Poisson integral,in a recent published article,a practical downward continuation method of airborne gravity data was used for the sea surveying areas using the differential conception in navigation and location for reference,in which the continuation corrections are calculated using ultra‐high‐degree geopotential model.In this paper,we continue using the same idea and develop the method to the application for land surveying areas.It suggests that terrain Information can be used to improve the calculated accuracy of continuation correction from geopotential model.The differential of local topographic corrections on flying height and corresponding ground point is added to the continuation correction from geopotential model,and it makes up the total continuation correction.It is ultimately realized to continue airborne gravity measurements to the ground in full frequency extension.EGM2008 geopotential model,ground gravity data and digital elevation model in high resolution are used as a case study to prove the efficiency of the new method.