融合多源数据构建区域航空重力梯度扰动全张量

通过联合全球重力位模型(EGM2008)、航空重力扰动数据和剩余地形模型(RTM)数据,基于频谱域(二维FFT变换)和空间域(Stokes数值积分)算法对毛乌素测区GT-2A航空重力测量系统采集的空中测线后处理重力扰动数据进行解算,构建了该地区的航空重力梯度扰动全张量.(1)残余航空重力扰动延拓结果表明:残余航空重力扰动经向下延拓至大地水准面,再向上延拓至航空高度后与原数据差值的标准差为1.0078 mGal,考虑边缘效应后,内缩计算范围得到的差值标准差减小至0.1269 mGal.(2)基于残余重力扰动数据(原航空高度数据及向下延拓数据),通过不同方案解算得到的梯度扰动结果表明:两种方案得到的研究区域重力梯度扰动各分量之差的最大标准差为6.4798E(Γ_(yz)分量),最小标准差为2.6968E(Γ_(xy)分量),内缩计算范围后得到的差值标准差最大值为1.8307E(Γ_(zz)分量),最小值为0.7223E(Γ_(yz)分量).本文的思路和方法可为未来我国自主构建航空重力梯度标定场提供参考.

Combining multi-source data to construct full tensor of regional airborne gravity gradient disturbance

In this paper, by combining EGM2008, airborne gravity disturbance and Residual Terrain Model (RTM) data, we calculated the full tensor of gravity gradients disturbance over Mu US surveying area in Inner Mongolia. The gravity disturbance data are post-processed from flight line gravity data collected by GT-2A airborne gravity measurement system. The spectral domain (2D FFT) and spatial domain (Stokes' numerical integration) algorithms have been applied to computing the full tensor gravity gradients disturbance respectively. (1) The continuation results of the residual airborne gravity disturbance show that: the standard deviation of the difference between the original residual airborne gravity disturbance and its counterpart which firstly continued downward to the geoid surface and then continued upward back to the aviation height is 1.0078 mGal. In order to alleviate the edge effects, the standard deviation of the difference obtained from the inner calculation range is reducing to 0.1269 mGal. (2) Based on the two type residual gravity disturbance data (the original and the downward continuation data): The maximum standard deviation of the differences of the gradients disturbance components calculated through different computational schemes is 6.4798E (difference of Γ_yz component), and the minimum standard deviation is 2.6968E (difference of Γ_xy component). The maximum standard deviation of the difference obtained from the inner calculation range is reducing to 1.8307E (difference of Γ_zz component), and the minimum standard deviation is reducing to 0.7223E (difference of Γ_yz component). The methods and results proposed in this paper could provide a reference for the future construction on airborne gravity gradient calibration field site in China independently.