Performance evaluation of the cold atom gravimeter WAG-H5-2#2508

The WAG-H5-2 atom gravimeter is an upgraded version of the WAG-H5-1. Compared with previous work, a highly integrated and stable optical system has been developed for the new gravimeter, based on the principle of matter–wave interferometry. The Comparison of Absolute Gravimeters for the CMONOC (Crustal Movement Observation Network of China) project was organized by the China Earthquake Networks Center from January 30 to March 30, 2026, in Wuhan. Our atom gravimeter (WAG-H5-2#2508) was invited to participate in this comparison. Absolute gravity at the indicated four sites was measured as requested by the organizer. Comparison results showed that no significant deviation existed between the WAG-H5-2#2508 atom gravimeter and laser interferometry absolute gravimeters, with deviations all within –4.3 to 6.1 μGal (1 μGal = 10⁻⁸ m/s²). The performance of our instrument in terms of sensitivity, precision, repeatability, stability, and accuracy were evaluated. The WAG-H5-2#2508 exhibited a short-term sensitivity of 16.2 μGal/Hz^1/2 and achieved an observation precision of ~1.0 μGal over 1000 s. The measurement precision was better than 0.4 μGal, based on one-day observation data. The repeatability was approximately 1.5 μGal. Long-term gravity monitoring over half a month at a sampling interval of 88 s showed that the residual was within 10 μGal. The deviation of 1.4 μGal during the comparison represents the accuracy of the instrument compared with several other gravimeters (FG5X, A10, and IGG-03B).