Evaluation of the External Accord Accuracy of Airborne Gravity Data with Upward Continuation

• Main Authors: JIANG Tao, XIAO Xuenian, DANG Yamin, ZHANG Chuanyin, LIU Zhanke
• Format: Article
• Language: zho
• Published: Surveying and Mapping Press 2018-05-01
• Series: Acta Geodaetica et Cartographica Sinica
• Subjects: airborne gravity; external accord accuracy; upward continuation; Poisson integral; FFT; cross validation
• Online Access: http://html.rhhz.net/CHXB/html/2018-5-567.htm

Three methods for evaluating the external accord accuracy of airborne gravity survey line data, namely the gradient based, the Poisson integral based and the fast Fourier transform (FFT) based upward continuation (UPC) of terrestrial gravity, are introduced. A cross validation method is proposed for the estimation of terrestrial gravity errors and their propagation at flight altitude. The external accord accuracy of airborne gravity survey line data over Mu Us in Inner Mongolia is evaluated based on the three UPC methods and the proposed cross validation method. Numerical results show that the gridding interpolation error and representative error of terrestrial gravity range from 0.66 to 0.92 mGal, which demonstrates the necessity of removing these errors for error estimation of airborne gravity data. The Poisson integral and the FFT based UPC method are capable of evaluating the external accord accuracy of airborne gravity data, both have comparative performance. Applying the methods for the data acquired by GT-2A airborne gravimetry system over Mu Us in Inner Mongolia, it turns out the external accord accuracy of the airborne gravity disturbances is better than 1.42 mGal(1 Gal=1×10^-2 m/s²) after the removal of terrestrial gravity error contribution,while some remaining integral edge effects still exist.