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The accurate measurement of local gravitational acceleration (g, normal value 9.81 m/s2) is a key approach to the exploration of the gravitational field of the earth, and it has been applied in metrology, geodesy, geodynamics, seismology, and mineral exploration. With the plan of '2000 national gravity network' and 'China crustal motion observation network', highly precision gravity measurement will be increasingly required in the long term. In order to further investigate the possible systematic error of current absolute gravity measurement, and satisfy various requirements for highly accurate gravity observation, the T-1 absolute gravimeter prototype is designed and built at Tsinghua University. The T-1 instrument adopts the classic free-fall scheme to measure the g value by tracking the trajectory of a free-fall motion in vacuum with a laser interferometer. The T-1 absolute gravimeter consists of several sub-systems: high vacuum free-fall chamber, compact laser interferometer, low-frequency vertical vibration isolation, high-speed signal acquisition system, instrument control and data processing system. The length and time standards used in g measurement are stabilized He-Ne laser and rubidium atomic clock respectively. It's well known that both of the two standards have an uncertainty of less than 1 10-9. The practical gravity measurement results of T-1 absolute gravimeter give a standard deviation of the mean of less than 1 upGal (1 up Gal = 10-8 m/s2) in a typical observation within 12 h. And the reproducibility of less than 3 upGal is verified by repeatedly measuring gravity. The T-1 absolute gravimeter is a promising instrument by which highly accurate gravity measurement at a microgal level can be realized, and it is hopefully to be used in many research and application areas.
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Keywords:
- absolute gravity measurement /
- laser interferometer /
- free-fall method
[1] Faller J E 2002 Metrologia 39 425
[2] Wang L J 2009 Atom Optics and Space Physics (Amsterdam: IOS Press) p465
[3] Guo Y G, Huang D L, Fang Y Y, Zhang G Y, Zhou J H, Xu J Y 1988 Acta Geophysica Sinica 31 73 (in Chinese) [郭有光, 黄大伦, 方永源, 张光远, 周景华, 徐进义 1988 地球 31 73]
[4] Zhang W M, Zhang C J 2002 Progress in Geophysics 17 180 (in Chinese) [张为民, 张赤军 2002 地球物理学进展 17 180]
[5] Origlia C, Quagliotti D, Berrino G, Corrado G, D'Errico V, Ricciardi G 2008 Annals of Geophysics 51 39
[6] Peter G, Moose R E, Wessells C W, Faller J E, Niebauer T M 1989 Journal of Geophysical Research 94 5659
[7] Niebauer T M, Sasagawa G S, Faller J E, Klopping F 1995 Metrologia 32 159
[8] Peters A, Chung K Y, Chu S 1999 Nature 400 849
[9] Xu X Y, Wang Y Z 1997 Acta Phys. Sin. 46 1062 (in Chinese) [徐信业, 王育竹 1997 46 1062]
[10] Zheng S L, Chen J, Lin Q 2005 Acta Phys. Sin. 54 3535 (in Chinese) [郑森林, 陈君, 林强 2005 54 3535]
[11] Ren L C, Zhou L, Li R B, Liu M, Wang J, Zhan M S 2009 Acta Phys. Sin. 58 8230 (in Chinese) [任利春, 周林, 李润兵, 刘敏, 王谨, 詹明生 2009 58 8230]
[12] Zhang W M, Wang Y, Zhou X H 2008 Progress in Geophysics 23 69 (in Chinese) [张为民, 王勇, 周旭华 2008 地球物理学进展 23 69]
[13] Liu D Z, Li H, Xing L L, Sun S A, Liu Z W, Xiang A M 2007 Journal of Geodesy and Geodynamics 27 88 (in Chinese) [刘冬至, 李辉, 邢乐林, 孙少安, 刘子维, 项爱民 2007 大地测量与地球动力学 27 88]
[14] Svitlov S, Maslyk P, Rothleitner C, Hu H, Wang L J 2010 Metrologia 47 677
[15] Svetlov S 1997 Gravity, Geoid and Marine Geodesy 117 (Berlin: Springer) 47
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[1] Faller J E 2002 Metrologia 39 425
[2] Wang L J 2009 Atom Optics and Space Physics (Amsterdam: IOS Press) p465
[3] Guo Y G, Huang D L, Fang Y Y, Zhang G Y, Zhou J H, Xu J Y 1988 Acta Geophysica Sinica 31 73 (in Chinese) [郭有光, 黄大伦, 方永源, 张光远, 周景华, 徐进义 1988 地球 31 73]
[4] Zhang W M, Zhang C J 2002 Progress in Geophysics 17 180 (in Chinese) [张为民, 张赤军 2002 地球物理学进展 17 180]
[5] Origlia C, Quagliotti D, Berrino G, Corrado G, D'Errico V, Ricciardi G 2008 Annals of Geophysics 51 39
[6] Peter G, Moose R E, Wessells C W, Faller J E, Niebauer T M 1989 Journal of Geophysical Research 94 5659
[7] Niebauer T M, Sasagawa G S, Faller J E, Klopping F 1995 Metrologia 32 159
[8] Peters A, Chung K Y, Chu S 1999 Nature 400 849
[9] Xu X Y, Wang Y Z 1997 Acta Phys. Sin. 46 1062 (in Chinese) [徐信业, 王育竹 1997 46 1062]
[10] Zheng S L, Chen J, Lin Q 2005 Acta Phys. Sin. 54 3535 (in Chinese) [郑森林, 陈君, 林强 2005 54 3535]
[11] Ren L C, Zhou L, Li R B, Liu M, Wang J, Zhan M S 2009 Acta Phys. Sin. 58 8230 (in Chinese) [任利春, 周林, 李润兵, 刘敏, 王谨, 詹明生 2009 58 8230]
[12] Zhang W M, Wang Y, Zhou X H 2008 Progress in Geophysics 23 69 (in Chinese) [张为民, 王勇, 周旭华 2008 地球物理学进展 23 69]
[13] Liu D Z, Li H, Xing L L, Sun S A, Liu Z W, Xiang A M 2007 Journal of Geodesy and Geodynamics 27 88 (in Chinese) [刘冬至, 李辉, 邢乐林, 孙少安, 刘子维, 项爱民 2007 大地测量与地球动力学 27 88]
[14] Svitlov S, Maslyk P, Rothleitner C, Hu H, Wang L J 2010 Metrologia 47 677
[15] Svetlov S 1997 Gravity, Geoid and Marine Geodesy 117 (Berlin: Springer) 47
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