Application of Zero Drift Correct and Detection of Scale Parameters of CG-5 Gravimeter

Using zero drift correction for single survey line data and a scale factor change detection method, we carried out fine processing of CG-5 gravimeter from dual survey observation data during 2014 for the Yunnan area; gravity variations in the area were obtained. The results show that: (1) a zero drift rate of CG-5 gravimeter varies significantly over time. In the first survey period, the zero drift rate of gravimeter C1169 and C1170 present a tendency of linear increase at a magnitude of 20×10^-8 m·s^-2·h^-1 variation. During the second survey period, the zero drift rate of the gravimeters tended to be stable. After zero drift correction, the observation precision improved substantially. (2) The scale factor of the C1170 gravimeter changed at a magnitude of-0.000 100. (3)After scale factor correction, the gravity variation showed a better agreement with the absolute observation result, and the gravity variation image can clearly reflect the difference between the two sides of the Zhaotong-Ludian faults and seismogenic background of the Ludian 6.5 earthquake, which verified the view that a large earthquake occurred in the positive-negative transition area of gravity variation. Systematic observation error can be effectively eliminated using our proposed method that obtains the real gravitational field change.