Static Measurement Experiment and Performance Analysis of GT-2A Airborne Gravimeter

A static measurement experiment and an elevator-platform test of GT-2A have been designed to determine the zero drift rate, resolving power and scale factor of the instrument. We have calculated the drift rate with the static continuous observations from GT-2A and a relative gravimeter, as well as the tidal gravity from solid tide model. Considering solid tide correction, the zero drift rate of GT-2A observations decreases from -6.5 μGal/h to -0.1 μGal/h, while the representative error caused by using the zero drift rate from calibration measurement decreases from 7.2 μGal/h to 1.1 μGal/h. Thus, we can see that the solid tide has great influence on the determination of zero drift rate. With these data, the ability for GT-2A to monitor solid tide can be tested. The results from frequency domain analysis shows that the tidal components whose amplitude exceeds 30 μGal can be seen in the amplitude-frequency diagram, which means the resolving power of GT-2A is about 30 μGal. The observations of GT-2A from the elevator-platform test can be used to calculate the vertical gradient of gravity, which is then compared with the result measured by the relative gravimeter. Then the scale factor of the instrument has been determined to be -0.003 4±0.011 6.