海域航空重力快速构建区域大地水准面

A fast approach for determining geoid using airborne gravity data of sea area

我国在海域开展了大规模的航空重力勘探,这些资料对构建高精度大地水准面具有重要价值.基于此,本文提出一种利用海域航空重力测量数据快速构建大地水准面的方法.该方法基于移去-恢复法思想,利用位场最小曲率方法对航空重力数据进行高精度向下延拓并获取相应的扰动位,实现航空重力测量快速构建海域大地水准面.与斯托克斯积分计算相比,采用了处理效率更高的频率域位场转换,解决了向下延拓及垂向积分时航空重力异常数据空白及扩边问题,具有较高的位场转换精度.本文应用EGM2008模拟航空重力数据进行模型验证,计算结果与其给出的水准面的精度相当;同时,也选取GRAV-D计划的航空重力数据进行实际验证,计算结果与xGEOID18B水准面模型精度基本一致.模型验证和实际应用验证了本方法的实用性.

Large scale airborne gravity survey of sea area has carried out in China,and these data are valuable for constructing high precision geoid.This paper presents a fast approach for determining geoid using airborne gravity survey data of sea area.Based on the idea of removal-recovery method,using the minimum curvature method of the potential field to perform high precision downward continuation of the airborne gravity data,we obtain the corresponding disturbance potential field,which can be converted into geoid by the Brun formula.Compared with the Stokes integral,the transform in frequency domain provides higher processing efficiency and accuracy,which solves the problem of data missing and edge expansion in both downward continuation and vertical integration.EGM2008 model was used for simulating airborne gravity data,and the calculation results are equivalent to the accuracy of geoid derived from EGM2008.At the same time,airborne gravity data of GRAV-D plan is also selected for physical verification,and the calculation results are basically consistent with the accuracy of xGEOID18B model.Model verification and practical application verified the practicability of the method.