Absolute gravimeter field gravity station fixed point measurement-Xi'an (Other fixed-point measurements)
WF-T-1 Absolute Gravimeter (Hardware and Software Introduction)
From August 30, 2018 to September 9, 2018, the T-1 absolute gravimeter conducted absolute gravity measurement experiments at the Urumqi GNSS reference station and the Altay GNSS reference station in Xinjiang. The Urumqi measurement point was continuously observed for 52 hours, while the Altay measurement point was continuously observed for 28 hours. The following images show the gravity observation sites of the T-1 absolute gravimeter at the Urumqi reference station and the Altay reference station, respectively.
T-1 Absolute Gravimeter at the Urumqi GNSS Reference Station in Xinjiang (August 30, 2018)
T-1 Absolute Gravimeter at the Altay GNSS Reference Station in Xinjiang (September 8, 2018)
The T-1 absolute gravimeter conducted gravity observations at the Urumqi GNSS reference station from 04:17:18 UTC on August 30, 2018, to 07:24:07 on September 1, 2018. A total of 103 sets of data were collected, with 2 sets per hour, and each set was measured consecutively 16 times (i.e., the free-fall was repeated 16 times in succession). The measurement results are shown in the figure below. The results indicate that the instrument's status was basically stable, and the group means of the measurements without tidal corrections corresponded well with theoretical tides.
Measurement results of the T-1 absolute gravimeter at the Urumqi GNSS reference station (corrected for solid Earth tides) Urumqi data (52 hours)
Measurement results of the T-1 absolute gravimeter at the Urumqi GNSS reference station (unadjusted for solid Earth tides)
The T-1 absolute gravimeter's gravity observations at the Altay GNSS reference station started at 12:20:06 UTC on 2018-09-07 and ended at 17:03:40 on 2018-09-08, with a total of 57 sets of data collected, 2 sets per hour, each set measured continuously 16 times. On the second day of measurement in Altay, rainfall occurred. Due to the relatively dangerous location of the observation point and the possibility of lightning during rain, the measurement time was shortened to ensure the safety of the instrument. The measurement results are shown in the following figure. The results indicate that the instrument was basically stable, and the uncorrected tidal group mean of the measurement data agrees well with the theoretical tides.
Measurement Results of the T-1 Absolute Gravimeter at the Altay GNSS Reference Station (Corrected for Solid Earth Tides)
Measurement Results of the T-1 Absolute Gravimeter at the Altay GNSS Reference Station (Uncorrected for Solid Earth Tides)
数据处理程序得到两批数据的测量均值和标准差，再进行B 类不确定度修正、计算合成不确定度后，分别得到乌鲁木齐和阿勒泰基准站的地面重力点的最终重力值测量结果。两个基准站的测量结果不确定度分别为6.4μGal 和6.5μGal，与新疆地震局提供的台站重力加速度参考值相比，偏差满足小于2 倍的仪器合成不确定度，所以T-1 型绝对重力仪测量结果与参考值符合。此外，此次远赴新疆的重力观测还进一步验证了T-1 型绝对重力仪经受远程运输的能力。2019 年10 月20 日至2019 年11 月15 日，T-1 型绝对重力仪再次赴新疆，于乌鲁木齐、木垒、独山子3 个基准站进行绝对重力观测。其中乌鲁木齐进行了长于48h 的连续测量，木垒和独山子基准站进行了长于25h 的连续测量。下图分别为T-1 型绝对重力仪在乌鲁木齐、木垒、独山子GNSS 基准站进行重力观测的图片和测量结果。测量结果表明仪器状态基本稳定，测量数据与理论潮汐吻合得较好。
T-1 Absolute Gravimeter at the Urumqi GNSS Reference Station Observation Site
T-1 Absolute Gravimeter at the Mulele GNSS Reference Station Observation Site
T-1 Absolute Gravimeter at the Urumqi GNSS Reference Station Observation Site
Measurement results of the T-1 absolute gravimeter at the Urumqi GNSS reference station (unadjusted for solid Earth tides)
Measurement results of the T-1 absolute gravimeter at the Urumqi GNSS reference station (corrected for solid Earth tides) Urumqi data (52 hours)
Measurement results of the T-1 absolute gravimeter at the Urumqi GNSS reference station (unadjusted for solid Earth tides)
Measurement results of the T-1 absolute gravimeter at the Urumqi GNSS reference station (corrected for solid Earth tides) Urumqi data (52 hours)
