2000国家大地坐标系椭球参数与GRS 80和WGS 84的比较

Parameters of the CGCS 2000 Ellipsoid and Comparisons with GRS 80 and WGS 84

根据2000国家大地坐标系(CGCS2000)的定义及其所定义的4个基本椭球常数,推导CGCS2000椭球的主要几何和物理参数,比较这些参数与GRS80和WGS84椭球相应参数之间的差异,给出CGCS2000椭球与GRS80及WGS84椭球定义的正常重力值的差异,并分析在CGCS2000及WGS84系下同一点坐标的差异。研究表明:CGCS2000椭球上的正常重力值与GRS80,WGS84椭球上的正常重力值的差值分别约为-143.54×10-8m/s2和0.02×10-8m/s2。同一点在CGCS2000与GRS80和WGS84下经度相同,纬度的最大差值分别为8.26×10-11″(相当于2.5×10-6mm)和3.6×10-6″(相当于0.11mm)。

According to the definition of China Geodetic Coordinate System 2000 （CGCS 2000） and defined constants of the ellipsoid adopted by CGCS 2000, the other geometrical and physical parameters of this ellipsoid are derived and compared with that from GRS80 and WGS 84, respectively. Meanwhile the coordinates and normal gravity on the CGCS 2000 ellipsoid are compared with that on WGS 84 and GRS 80. The difference between the normal gravity on CGCS 2000 ellipsoid and that on GRS80 is about 143.54×10^-8 m/s^2,while it is0.02×10^-8 m/s^2compared to WGS84. The longitudes of a point on these three ellipsoids are the same, but the maximum difference of latitude between CGCS 2000 andGRS80 is 8.26×10^-11arc seconds, which is about 2.5×10 ^-6 mm, and the maximum difference of latitude between CGCS2000 and WGS84 is3.6×10 ^-6arc seconds, which is about 0.11mm.