【3 结 论】
利用不同重力场模型(EGM2008、EIGEN-6C4)和海面高模型(DNSC08、DTU10、DTU13)计算了平均海面重力位均值为62 636 856.550 7 m2s-2，加入相应的海面地形模型改正后计算的大地水准面重力位均值为62 636 858.179 0 m2s-2。
分别利用3种不同的方法确定了我国1985国家高程基准与全球高程基准(全球平均海面/全球大地水准面)之间的垂直偏差，其中高程异常差法精度最高，正常高反算法次之，异常位法精度最差。利用以上3种方法计算的垂直偏差之间存在差异，最大差异为0.152 6 m/0.152 5 m(约1.5 m2s-2)。该差异主要来自于正常高，本文采取合理的加权的方法来减弱低精度正常高数据对计算垂直偏差的影响。改善结果为，当Pi=1/D时最大差异为0.057 6 m /0.057 6 m (约0.6 m2s-2);当Pi=1/H时最大差异为0.040 1 m/0.040 1 m (约0.4 m2s-2)。
两种验证方法计算表明：加权后计算的m=H-(WD-WP)/γ值更趋于0，且加权后计算的垂直偏差受外界影响明显小于加权前。
如果将3种方法计算的6组垂直偏差数据取均值作为我国高程基准与全球高程基准的垂直偏差，可以得到我国85高程基准高于全球平均海面0.298 0 m，高于全球大地水准面0.464 2 m。
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文/赫林1, 李建成1,2, 褚永海1,2
1. 武汉大学测绘学院, 湖北 武汉 430079 ;
2. 武汉大学地球空间环境与大地测量教育部重点实验室, 湖北 武汉 430079
收稿日期：2016-01-19; 修回日期：2016-04-11
基金项目：测绘地理信息公益性行业科研专项(201512001); 国家973计划(2013CB733301); 国家863计划(2013AA122502)
第一作者简介： 赫林(1988-),女,博士生,研究方向为全球高程基准统一。
E-mail:helin928926@163.com
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