国家高程基准 meaning in Chinese

national height datum

Then the origin vertical shift of cnhd85 with respect to whd is calculated from geopotentials . and the systematic difference and its distribution of cnhd85 is analyzed from the difference of height anomalies . at last , the systematic difference of the mean sea level at qingdao tide gauge is further testified from the sea surface topography model
然后基于位理论方法求出了1985国家高程基准点的垂直偏差，基于高程异常差分析了1985国家高程基准的系统差及其分布规律，最后基于海面地形模型进一步揭示了青岛验潮站平均海平面的系统差。