我国陆海统一似大地水准面构建的三维重力矢量法

基于重力场水平分量-垂线偏差对地形信息敏感的特点，根据边值理论由重力与地形数据确定格网垂线偏差模型，在此基础上，首先利用三维重力矢量-格网垂线偏差与格网重力异常，联合格网高程数据求得格网点间高程异常差，然后通过GPS/水准点的控制，构成紧密的几何条件，进行严密平差，从而获得高分辨率、高精度似大地水准面的数值模型。按照本文方法，利用我国6600多个GPS/水准点、1'×1'的格网垂线偏差、格网重力异常、格网高程数据，整体平差计算了我国陆海统一的似大地水准面模型，经GPS/水准点检核，全国似大地水准面的绝对精度达到了4 cm，相对精度优于7 cm。

The 3D Gravity Vectors Method in China Land and Ocean Quasi-geoid Determination

The horizontal component of earth gravity field-vertical deflection is very sensitive to the information of terrain.Firstly,using 3D gravity vectors-grid vertical deflections which are calculated by gravity and terrain data by solving physical geodetic boundary value problems (GBVP),grid gravity anomaly and grid terrain data to calculate the differences of height anomaly,then,with the control of GPS/leveling points to form rigorous geometric conditions,after that,the grid height anomaly is calculated by L-S adjustment method.Finally,a quasi-geoid model with a high precision and resolution is achieved. Based on the method presented,a national quasi-geoid model is built which includes land and ocean by using more than 6600 GPS/leveling points data,1′×1′grid vertical deflections,grid gravity anomaly and grid terrain data.Compared with the GPS/leveling points,the absolute precision of our national quasi-geoid is about 4 cm,while the relative precision is better than 7 cm.