iGrav-012超导重力仪定期格值结果分析

利用绝对重力仪FG5X-249与超导重力仪iGrav-012在中国计量科学研究院昌平院区开展连续同期同址观测,通过最小二乘回归分析法对iGrav-012超导重力仪进行定期格值标定。2014年至2017年间的相关计算结果表明:iGrav-012超导重力仪每年的格值因子精度均优于0. 1%;当绝对重力仪FG5X-249的下落次数超过6 000次时,即可得到稳定的格值因子;格值因子年最大变化量低于0. 6 nm·s^-2·V^-1,每年格值一次即可达到精度要求。iGrav-012超导重力仪可以作为国家重力计量基准仪器的组成部分,为2017年全球绝对重力仪关键比对CCM. G-K2. 2017期间的重力测量结果建立时间链接,比对结束后用于重力测量量值的溯源。

Analysis of Calibration Factor of Superconducting Gravimeter iGrav-012

FG5X-249 absolute gravimeter and iGrav-012 superconducting gravimeter were observed in the same period and site in Changping campus of National Institute of Metrology, China. The calibration factor of iGrav-012 superconducting gravimeter is calculated by the method of least squares regression analysis. The calculation results from observations during the year of 2014 to 2017 showed that the relative calibration factor accuracy of each year is better than 0.1%. When the drop numbers of FG5X-249 absolute gravimeter is more than 6000, the calibration factor can be stable. According to the analysis result the annual maximum variation is less than 0.6nm·s^-2·V^-1, so that calibration once a year can meet the requirements of accuracy. The iGrav-012 can be used as part of national metrologia reference standard of gravity measurement, provide the gravity variation with time link during the international key comparison of absolute gravimeters CCM.G-K2.2017 and be used for the traceability of absolute gravimeters after comparison.