从高程系统定义出发，探讨高程基准面的重力等位性质，测试分析不同类型高程系统地面点高程之间的差异，考察GNSS代替水准与实际水准测量成果的一致性，进而提出新的GNSS代替水准算法。主要结论包括：①当精度要求达到厘米级水平时，正常高的基准面也应是大地水准面。中国国家1985高程基准采用正常高系统，其高程基准面是过青岛零点的大地水准面。②近地空间中等解析正高面与大地水准面平行，GNSS代替水准能直接测定地面点的解析正高，但正常高系统更有利于描述地势和地形起伏。③本文给出的GNSS代替水准测定近地点正常高算法，大地高误差对正常高结果的影响比大地水准面误差大，前者影响约为后者的1.5倍。
Based on the definition of height system, the gravitational equipotential property of height datum surface is discussed in this paper, differences of the heights at ground points that defined in different height systems are tested and analyzed as well. A new method for replacing leveling using GNSS is proposed to ensure the consistency between GNSS replacing leveling and spirit leveling at mm accuracy level. The main conclusions include:①For determining normal height at centimeter accuracy level, the datum surface of normal height should be the geoid. The 1985 national height datum of China adopts normal height system, its datum surface is the geoid passing the Qingdao zero point.②The surface of equi-orthometric height in the near earth space is parallel to the geoid. The combination of GNSS precise positioning and geoid model can be directly used for orthometric height determination. However, the normal height system is more advantageous for describing the terrain and relief.③Based on the proposed method of GNSS replacing leveling, the errors in geodetic height affect more on normal height result than the errors of geoid model, the former is about 1.5 times of the latter.
[1] 党亚民,章传银,陈俊勇,等.现代大地测量基准[M].北京:测绘出版社,2015. DANG Yamin,ZHANG Chuanyin,CHEN Junyong,et al.Modern Geodetic Datum[M].Beijing:Surveying and Mapping Press,2015.
[2] 孔祥元,郭际明,刘宗泉.大地测量学基础[M].2版.武汉:武汉大学出版社,2010. KONG Xiangyuan,GUO Jiming,LIU Zongquan.Foundation of Geodesy[M].2nd ed.Wuhan:Wuhan University Press,2010.
[3] HOFMANN-WELLENHOF B,MORITZ H. Physical Geodesy[M].New York:Springer,2006.
[4] ARDALAN A A,SAFARI A.Global Height Datum Unification:a New Approach in Gravity Potential Space[J].Journal of Geodesy,2005,79(9):512-523.
[5] BALASUBRAMANIA N.Definition and Realization of a Global Vertical Datum[R].Ohio:Department of Geodetic Science and Surveying,the Ohio State University,1994:112.
[6] BLEWITT G.Self-consistency in Reference Frames,Geocenter Definition,and Surface Loading of the Solid Earth[J].Journal of Geophysical Research,2003,108(B2):2103.
[7] FILMER M S,FEATHERSTONE W E,KUHN M.The Effect of EGM2008-based Normal,Normal-orthometric and Helmert Orthometric Height Systems on the Australian Levelling Network[J].Journal of Geodesy, 2010,84(8):501-513.
[8] 国家测绘局.GB/T 12897-2006国家一、二等水准测量规范[S].北京:中国标准出版社,2006. National Bureau of Surveying and Mapping.GB/T 12897-2006 Specifications for the First and Second Order Leveling[S].Beijing:China Standard Press,2006.
[9] IHDE J,SÁNCHEZ L.A Unified Global Height Reference System As a Basis for IGGOS[J].Journal of Geodynamics,2005,40(4-5):400-413.
[10] 李建成.最新中国陆地数字高程基准模型:重力似大地水准面CNGG2011[J].测绘学报,2012,41(5):651-660. LI Jiancheng.The Recent Chinese Terrestrial Digital Height Datum Model:Gravimetric Quasi-geoid CNGG2011[J].Acta Geodaetica et Cartographica Sinica,2012,41(5):651-660.
[11] LAVALLÉE D A,VAN DAM T,BLEWITT G,et al.Geocenter Motions from GPS:A Unified Observation Model[J].Journal of Geophysical Research,2006,111(B5):B05405.
[12] MORITZ H.Geodetic Reference System 1980[J].Journal of Geodesy,2000,74(1):128-133.
