Metrological traceability method for atomic absolute gravimeters

Cold atomic gravimeters are attracting more and more attention and activity in the area of gravity measurement and comparison, and the corresponding methods for measurement and traceability need to be explored. Based on two self-developed cold atomic gravimeters, research on the comparison and traceability methods of absolute gravity measurement was carried out. The entire gravity measurement traceability process is divided into two stages: the preliminary traceability in the laboratory and the formal traceability in the absolute gravity reference station. Through comparison of two atomic gravimeters (ZAG-E and ZAG-B) in the laboratory, the degree of equivalence D-D and the normalized deviation E-n of ZAG-E are obtained, which are -2.7 +/- 7.6 mu Gal (k = 2) and -0.3599, respectively. Relative to the absolute gravity reference at the National Institute of Metrology (NIM) in China, D-D and E-n of ZAG-E are 0.5 +/- 12.0 mu Gal (k = 2) and 0.0417, respectively. |E-n| <= 1 in the two traceability stages, so the results of two traceability stages are acceptable, which indicates the consistency of the comparisons is good. Finally, the absolute gravity measurement value of ZAG-E is traced to the SI units, ensuring its accuracy. A gravity traceability method for atomic gravimeters is given and is very beneficial for the applications of atomic gravimeters in metrology and other fields. (C) 2021 Optical Society of America