Construction of a Test Field for Relative Gravimeters in a Cave With a Cold Atom Gravimeter

The Earth's gravity field is complex and variable. Performance evaluation of gravimeters requires gravity fields with well-known absolute gravity values. The aim of this study is to utilize an in-house developed cold atom gravimeter (CAG-E) in conjunction with CG-5 to establish a comprehensive test field consisting of 13 gravity datums at different altitudes. This absolute gravity field can be used for testing multiple relative gravimeters at the same time. The additional theoretical model calculations of this test field can provide a reference for gravity values at different heights, and a 3-D test field can be constructed in the future. In addition, a detailed performance evaluation of CAG-E was performed where the accuracy of the instrument repeatability was found to be 4.8 mu Gal. Finally, a correction of the geological density of the mountain was carried out using the absolute gravity values, and a minimum gravity difference residual of 0.9 mu Gal was obtained. These results verify the reliability of this test field for relative gravimeters.