引潮位的Doodson规格化展开及其精度评定

基于引潮位Doodson规格化展开的基本原理以及ELP/MPP02月球历表、Newcomb太阳历表的结构,设计了一个用以代表三角函数的数据结构;并由此自定义了三角函数的乘法与加法算法,将月球、太阳引潮位分别展开至5阶、3阶,振幅绝对值截断阈值为10-7,在展开过程中对"伪波"进行"滤波"处理后,最终得到包含4 686项展开式的引潮位展开表(其中振幅绝对值超过10-6的展开式有2 441项)。以德国BFO(Black Forest Observatory)测站为例,基于DE431历表,通过天球参考系变换计算得到1950—2050年间时间间隔为1 h的法向引潮力基准序列BFDE431;并根据各个引潮位展开表计算得到相应的法向引潮力序列;通过与BFDE431基准序列求差,得到各个差值序列的统计值。计算结果表明,文中给出的展开表对应的差值序列数值在±58×10~(-11)m·s~(-2)(nGal)以内,均方差为12.5×10~(-11)m·s~(-2),与XI89展开表的精度相当。但由于没有考虑行星及地球扁率的影响,仍未达到HW95和RATGP95展开表的精度水平。

The Doodson Normalized Development of Tidal Generating Potentialand Its Precision Evaluation

Aimed at the Doodson normalized development of Tidal Generating Potential (TGP),based on the TGP theoretical formula and the structure of ELP/MPP02 lunar ephemeris and Newcomb solar ephemeris,a new data structure had been designed which can represent the trigonometric function and then customized the multiplication and addition algorithm of the trigonometric function.The TGP of lunar and solar were developed to 5 and 3 degree respectively,the truncation threshold of the absolute value of the amplitude is 10-7.The pseudo waves were filtered in the development process and then the TGP development catalogue was obtained which contains 4 686 expanding terms in which there are 2 441 terms whose amplitude absolute value are more than 10-6.Taking the Black Forest Observatory(BFO)station as an example,based on DE431 ephemeris and the celestial reference system transformation,the normal Tidal Generating Force(TGF)datum sequence BFDE431 between 1950 and 2050 with 1 hour time interval was calculated.Then the corresponding normal TGF sequence was computed according to the development catalogues and the statistic values of each difference sequence were obtained.The results show that the difference sequence values corresponding to the catalogue given in this paper are within ±58×10-11m·s-2,the RMS is 12.5×10-11m·s-2,the precision is equivalent with that of the XI89 catalogue.But because of without considering the effect of planets and the earth flattening,the precision has not yet reached that of HW95 and RATGP95 catalogue.