GT-2A航空重力仪静态测量实验及性能分析

Static Measurement Experiment and Performance Analysis of GT-2A Airborne Gravimeter

  • 摘要: 设计静态测量实验和升降台实验对GT-2A航空重力仪的零漂率、分辨力和尺度因子进行分析。利用GT-2A定点静态连续观测数据、相对重力仪同步观测数据和固体潮模型计算的重力固体潮数据,计算了GT-2A的零漂率。固体潮改正之前和之后的计算结果表明,采用GT-2A连续静态观测数据计算的零漂率差值最大可达7.4 μGal/h;采用施测前后校准测量数据计算零漂率引入的代表误差最大为13.7 μGal/h。以上结果表明固体潮对零漂率的确定具有较大影响。测试GT-2A观测重力固体潮的能力,通过频域分析发现幅值超过30 μGal的分潮波会对GT-2A测量结果的幅-频特征产生影响,认为GT-2A的分辨力约为30 μGal。升降台实验中利用GT-2A测定重力垂直梯度,与相对重力仪测得的重力垂直梯度比较,计算出GT-2A实验量程内观测数据的尺度因子为-0.003 4 ±0.011 6。

     

    Abstract: A static measurement experiment and an elevator-platform test of GT-2A have been designed to determine the zero drift rate, resolving power and scale factor of the instrument. We have calculated the drift rate with the static continuous observations from GT-2A and a relative gravimeter, as well as the tidal gravity from solid tide model. Considering solid tide correction, the zero drift rate of GT-2A observations decreases from -6.5 μGal/h to -0.1 μGal/h, while the representative error caused by using the zero drift rate from calibration measurement decreases from 7.2 μGal/h to 1.1 μGal/h. Thus, we can see that the solid tide has great influence on the determination of zero drift rate. With these data, the ability for GT-2A to monitor solid tide can be tested. The results from frequency domain analysis shows that the tidal components whose amplitude exceeds 30 μGal can be seen in the amplitude-frequency diagram, which means the resolving power of GT-2A is about 30 μGal. The observations of GT-2A from the elevator-platform test can be used to calculate the vertical gradient of gravity, which is then compared with the result measured by the relative gravimeter. Then the scale factor of the instrument has been determined to be -0.003 4±0.011 6.

     

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