Participation in the absolute gravity comparison with a compact cold atom gravimeter

The first Asia-Pacific Comparison of Absolute Gravimeters ( APMP.M.G-K1) was organized by the National Institute of Metrology (NIM) of China from December 21, 2015 to March 25, 2016 in Changping, Beijing. Our compact cold atom gravimeter (CCAG) was transported from Hangzhou to Beijing with a long distance of about 1200 km to participate in this comparison. The CCAG is the only one, to the best of our knowledge, that is based on the principle of atom interferometry among all the instruments. Absolute gravity in the indicated three test sites has been measured as requested by the organizer. The sensitivity of our CCAG is estimated to be 90 mu Gal/root Hz, even when the measurements are carried out without any vibration isolation. Besides, the accuracy of this gravimeter has been evaluated to be about 19 mu Gal by considering the significant system errors. Our results show a good agreement with the given reference value.