13 Li Z X, Li H, Li Y F, et al. Non-tidal variation in the deflection of the vertical at Beijing observatory. J Geodesy, 2005, 78: 588-593
[7]
21 Schoebel R, Hein G W, Eissfeller B. Renaissance of astrogeodetic levelling using GPS/CCD zenith camera. In: Institute of Navigation (ION), eds. Proceedings of the IAIN World Congress and the 56th Annual Meeting of The Institute of Navigation, 2000 June 26-28, San Diego, CA. 2000. 732-740
[8]
22 Hirt C. The digital zenith camera TZK2-D a modern high precision geodetic instrument for automatic geographic positioning in real time. In: Payne H E, Jedrzejewski R I, Hook R N, eds. Proceedings of the 12th Meeting of the Astronomical Data Analysis Software and Systems of the Space Telescope Science Institute -ASP Conference Series 295, Astronomical Society of the Pacific, USA, 2003. 156-159
[9]
25 Hirt C, Bürki B, Somieski A E, et al. Modern determination of vertical deflections using digital zenith cameras. J Survey Eng, 2010, 136: 1-12
[10]
26 Bürki B, Müller A, Kahle H G. DIADEM: The new digital astronomical deflection measuring system for high-precision measurements of deflections of the vertical at ETH Zurich. CHGeoid2003, Report 03-33 A, Bundesamt für Landestopographie (swisstopo), Wabern, Schweiz. 2003
[11]
30 Abele M, Balodis J, Janpaule I, et al. Digital zenith camera for vertical deflection determination. Geodesy Cartogr, 2012, 38: 123-129
[12]
32 Ogrizovic V. A construction of an advanced measuring system for astro-geodetic determinations. Publ Astron Obs Belgrade, 2009, 86: 145-150
[13]
33 Hirt C, Kahlmann T. Hochpr?zise Neigungsmessung mit dem elektronischen Pendelneigungssensor HRTM (in German). Zeitschrift für Vermessungswesen, 2004, 129: 266-276
15 Han Y B, Ma L H, Hu H, et al. Application of astronomic time-latitude residuals in earthquake prediction. Earth Moon Planets, 2007, 100: 125-135
[24]
16 Li Z X, Li H. Earthquake-related gravity field changes at Beijing-Tangshan gravimetric network during1987-1998. Stud Geophys Geodaet, 2009, 53: 185-197
19 Barlik M, Rogowski J B. Variations of the plumb-line direction obtained from astronomical and gravimetric observations. Prace Nauk Politech Warsz, 1989, 33: 19-101
[28]
20 Jekeli C. An analysis of vertical deflections derived from high degree spherical harmonic models. J Geodesy, 1999, 73: 10-22
[29]
23 Hirt C, Reese B. High-precision astrogeodetic determination of a local geoid profile using the digital zenith camera system TZK2-D. CHGeoid 2003, Report 03-33 A, Bundesamt für Landestopographie (swisstopo), Wabern, Schweiz, 2004
[30]
24 Hirt C. Monitoring and analysis of anomalous refraction using a digital zenith camera system. Astron Astrophys, 2006, 459: 283-290
[31]
27 Gerstbach G, Pichler H. A small CCD zenith camera (ZC-G1)-developed for rapid geoid monitoring in difficult projects. Publ Astron Obs Belgrade, 2003, 75: 221-228
[32]
28 Kudrys J. Automatic determination of vertical deflection components from GPS and zenithal star observations. Acta Geodyn Geomater, 2007, 4: 169-172
[33]
29 Halicioglu K, Deniz R, Ozener H. Digital zenith camera system for Astro-Geodetic applications in Turkey. J Geodesy Geoinform, 2012, 1: 115-120
[34]
31 Ron C, ?tefka V, Vondrák J. The new CCD zenith tube. Pro Int Astron Union, 2007, 3: 120-121