外国网站下载的用于行星星历计算，包括各种时间的计算和转换，岁差、章动等的计算。-Foreign website for planetary ephemeris calculation, including the various time calculation and the calculation of the conversion, precession, nutation.

FRAME地固系和惯性系坐标转换（极移、岁差、章动、参考历元）-FRAME orbit transfer

计算长时间尺度上的地球轨道参数，包括偏心率，地轴倾角和岁差-Earth' s orbital parameters calculation time scales, including the eccentricity, the earth' s axis tilt and precession