Study on absolute calibration method of gPhone gravimeter

The gravity stations in Chinese are mainly equipped with gPhone relative spring gravimeters (about 62 sets), which lack calibration by absolute gravity and restrict the scientific utilization with their high-precision continuous gravity data． The FG5 absolute gravity and the gPhone observation data at the same site from the Chinese 12 gravity stations were collectd, gPhone gravimeter calibrating method by FG5 absolute gravity simultaneous observations based on the constraints of the DDW-NHi global tidal model was proposed, and it was compared with the gPhone gravimeter factory scale factor method and the theoretical tide calibration method for the DDW-NHi． At last, the future strategy of absolute gravity calibration was discussed． It's shown that when the gPhone gravimeters are calibrated by the absolute observation time for 26~64 h at the same site, the relative error is about ±0.001 3~ ±0.003 8． The gravity residual amplitude of each station in the absolute calibration result is generally ≤1×10-8 m/s2, reaching the nominal accuracy of gPhone gravimeter, which is better than the calculation results of factory scale factor or theoretical tide calibration method．The gravity residual amplitude corrected by the earth tide and air pressure is consistent with the ocean tidal load in Chinese mainland． © 2022 Huazhong University of Science and Technology. All rights reserved.