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Tianjin, China

Xing L.,China Earthquake Administration | Li H.,China Earthquake Administration | Li J.,61365 Troops | Zhang W.,CAS Wuhan Institute of Geodesy and Geophysics | He Z.,Shaanxi Administration of Surveying
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2016

The high accuracy absolute gravity datum covered the Chinese mainland area is established by using absolute gravity measurement data of one hundred stations in CMONOC(Crustal Movement Observation Network of China), the accuracy of each station is better than 5.0 μGal/a. The high accuracy gravity datum can be used for relative gravity measurements in adjustment, and the real gravity value can be determined from relative gravity measurement data of adjustment by using the gravity datum to avoid distortion of the real figure of gravity change. The trend of absolute gravity change from several observations at Chengdu station shows that the secular trend of gravity change is larger than 5.01±0.7 μGal/a, which is probably caused by the distribution of mass below the earth. The rate of land subsidence of Wuhan area is 3.27±0.65 mm/a determined from combined long-term absolute gravity measurements and GRACE satellite data according to the two system difference. © 2016, Surveying and Mapping Press. All right reserved.

Sun J.,61365 Troops | Zhu M.,61365 Troops
Journal of Geomatics | Year: 2014

This paper gives a brief introduction of the reference station setup principle. And together with the actual observed data it analyzes the influence caused by the distance between reference station and line to the accuracy of airborne gravity survey. The result shows that when the distance is 360 km, the standard derivations of the crossing point discrepancy gravity anomaly is ±2.0816 mGal,which is up to standard. So at the area , it is hard to setup GPS reference station, and it is necessary to loosen the distance principle to setup GPS station.

Liu X.,61365 Troops | Chen Q.,61365 Troops
Journal of Geomatics | Year: 2013

The astronomic eccentric reduction formulas in the orientating launch survey are proposed, whose applicability is analyzed by some experimental data. The precisions of astronomic eccentric reduction are not larger than 0.2 "of latitude, 0.01 s of longitude, 1" of azimuth only if the eccentricity is less than 1000m in the flat zones of middle latitude.

Ji L.,61365 Troops | Zhang Q.,65015 Troops | Zhang H.,61365 Troops | Li J.,61365 Troops | And 2 more authors.
Journal of Geomatics | Year: 2014

This paper analyzes the Earth tide and ocean loading tide in the absolute gravity measurements at the coastal fiducial station, and the accuracy statistics calculated by the different tide models, the results indicate the correction of the absolute gravity measurements near the ocean by the global ocean models are not very accurate. And the ocean loading tide correction of the relative gravity measurements are analyzed.

Liu Z.,61365 Troops | Zhang Z.,61365 Troops | Pang F.,61365 Troops
Journal of Geomatics | Year: 2014

The surveying equipment is the main equipment to complete the task of surveying and mapping. Because equipment working area is very wide, chang able, and persons of management and using equipment change frequently, management equipment is very difficult. This paper contrasts and analyses the characteristics of using the surveying equipment, and the characteristics of method for management equipment. And then this paper introduces the methods and suggestions for scientific management on surveying equipment under the condition of information.

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