Airborne Gravimetry of GEOHALO Mission: Data Processing and Gravity Field Modeling
Airborne Gravimetry of GEOHALO Mission: Data Processing and Gravity Field Modeling
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GEOHALO机载重力测量任务：数据处理和重力场建模
DOI：
10.1002/2017jb014425
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发表时间：
2017-12-01
影响因子：
3.9
通讯作者：
Li, Min
中科院分区：
文献类型：
--
作者：
Lu, Biao;Barthelmes, Franz;Li, Min
航空重力测量是提高对地球重力场认识的重要手段，特别是在难以到达的地区。航空重力测量的精度一般为几个毫伽，适合于填补卫星全球重力场模型中所谓的极隙。这里介绍了基于GEOHALO使命在意大利上空的航空重力测量的一些调查。为了从重力仪测量的值中减去垂直加速度，从全球导航卫星系统记录中得出了四种不同版本的运动加速度。为了去除高频噪声，将截止波长为200 s的低通滤波器应用于Chekan-AM测量值和来自GNSS的运动加速度。为了研究如何设计未来的空中重力运动，一个专用的飞行轨迹重复了两次，表明设备在更高的高度和速度下也能正常工作。根据最后的最佳结果，交叉点处重力差的RMS为1.4 mGal，根据误差传播定律，这意味着单次测量的精度为1.4/root 2，近似于1 mGal。为了演示如何通过航空测量改进仅卫星重力场模型，计算了GEOHALO区域的重力场模型。为了计算改进的区域大地水准面模型，点质量模型（PMM）和删除计算恢复（RCR）技术，使用最近的卫星模型和残留地形模型（RTM），被应用。最后，使用全球导航卫星系统/水准点来检查区域点质量模型的质量。
Airborne gravimetry is a crucial method to improve our knowledge about the Earth gravity field, especially in hard-to-access regions. Generally, the accuracy of airborne gravimetry is several milligals, which is suitable for filling the so-called polar gaps in satellite-derived global gravity field models. Here some investigations based on airborne gravity measurements from the GEOHALO mission over Italy are presented. To subtract the vertical accelerations from the values measured by the gravimeter, four different versions of kinematic accelerations were derived from Global Navigation Satellite Systems (GNSS) recordings. To remove the high-frequency noise, a low-pass filter with a cutoff wavelength of 200 s was applied to both Chekan-AM measurements and kinematic accelerations from GNSS. To investigate how future airborne gravity campaigns could be designed, a dedicated flight track was repeated two times showing that the equipment worked well also at higher altitude and speed. From the final best results follows an RMS of gravity differences at crossover points of 1.4 mGal, which, according to the law of error propagation, implies the accuracy of a single measurement to be 1.4/root 2 approximate to 1 mGal. To demonstrate how a satellite-only gravity field model can be improved by airborne measurements, a gravity field model for the GEOHALO region has been computed. To compute also an improved regional geoid model, the point mass modeling (PMM) and the remove-compute-restore (RCR) technique, using a recent satellite-only model and residual terrain modeling (RTM), were applied. Finally, GNSS/leveling points have been used to check the quality of the regional point mass model.