Theory and results of Taiwan Airborne Gravity Survey
Speaker: Yu-tsung Lo
Abstract
Airborne gravity survey has been carried out in Taiwan from2004 to 2005 with the latest airborne gravimeter. The GPS fixed stations of MOI (Ministry of Interior) and FB (Forest Bureau) were used to compute the air gravity. The surveying area covered all Taiwan island and nearby sea. The flying altitude was about 5156m and the speed was approximately 306km per hour. The task took us 43 working days and the number of flight hours is more than 200. The airborne gravimetry was implemented by local instrument, working group, and software and this is the only one case in Asia. The items we finished include (1) the best method to compute the position, velocity and acceleration of aircraft. (2) The analysis of upward and downward continuations. (3) The analysis of crossover tests. (4) Gravity anomaly computation with airborne gravity data. (5) Geoid and Bouguer anomaly computation. The RMS of crossover analysis is 3.5mgal after the bias correction. The accuracy of geoid is about 11 cm. Bouguer anomaly are very different between surface data and downward continuation of airborne survey.
Reference
Hwang, C., Hsiao, Y.-S., Shih, H.-C., Ming Yang, Chen, K.-H., Forsberg, R., Olesen, A. V. (2007) Geodetic and geophysical results from a Taiwan airborne gravity survey: Data reduction and accuracy assessment. Journal of Geophysical Research, vol. 112, B04407.
Hwang, C., Hsiao, Y.-S., Shih, H.-C. (2006) Data reduction in scalar airborne gravimetry: Theory, software and case study in Taiwan. Computers & Geosciences 32, 1573-1584