在空域,利用严密的向上延拓公式将地面重力数据上延至空中不同高度,而后与相应的地面重力数据比较从而得到不同高度的代表误差.在频域,构建了新的代表误差模型,计算了不同高度、不同分辨率下的代表误差.实际算例表明,在空域,对于地形平坦区域,在1 km高度以下,5'空中重力数据直接代表地面重力数据的误差小于1×10-5 m/s2.对于地形复杂区域；当空中测量高度大于1 km时,空中重力数据的代表误差大于3.3×10-5 m/s2,因此必须考虑向下延拓的问题.在频域,当高度小于7 km时,代表误差与高度及分辨率之间不再是简单的线性关系；当高度大于7 km时,代表误差随着分辨率的减小而减小,随着高度的增加而增加.%In space domain, air gravity data can be acquired by upward continuation of land gravity data based on the rigorous integral formula. Then the representative error can be obtained through the comparison between the air gravity data and corresponding land gravity data. The actual computation results show that the representative error of 5' air gravity data is about 1 × 10-5 m/s2 m flat area under the 1 km height. For the area yf complex terrain, the representative error is about 3. 3× 10-5 m/V when the surveying height is more than 1 km, so the downward continuation must be considered in the use of airborne gravimetry data. In frequency domain, the new gravity anomaly degree variance model is constructed based on EGM2008 model. Then the representative error of different height and different resolution are computed in frequency domain. The results show that the relationship between representative error and height is not simply the linear relation when the height is smaller than 7 km, and the representative error is becoming smaller with the resolution reducing.
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