Influences Of CGCS2000Enablement To Astronomical Positioning And Orientation

All kinds of models and methods correlated with astronomical positioning and orientationwere changed for the using of the new astronomical surveying system and method based on theenablement of CGCS2000. Influences of the changes to astronomical positioning and orientationwere discussed clearly in this paper. Main contents of the thesis were as follows1. Time systems and coordinate systems associated with astronomical positioning andorientation were introduced. Transformations between them were given clearly. Theories andmethods of astronomical positioning and orientation were discussed. The vector calculationmethod of apparent position of celestial bodies was researched.2. JPL ephemerides were introduced, influences of ephemerides to apparent position ofcelestial bodies were compared detailedly. Results of astronomical orientation observed throughstars, the Sun, the Moon and planets, were compared and analyzed detailedly in differentephemerides.3. The epoch of hipparcos catalogue was transformed. HIP2000catalogue was designed forastronomical orientation. Mean positions and apparent positions were compared. Astronomicalconstant systems were introduced and analyzed.4. Targit, Zinger and multi-star approximate equal altitude methods were compared andanalyzed in different catalogue systems. Differences of astronomical orientation observedthrough stars and Polaris were analyzed.5. Influences of precession and nutation to position of celestial bodies were researched.Differences of the precession and nutation models were analyzed. Transformations of GCRS toITRS were introduced and compared. Influences of the transformation to astronomicalorientation were analyzed.6. Influences of day length and polar motion prediction to latitude，longitude and azimuthwere researched. Influences of day length and polar motion prediction error to astronomicalpositioning and orientation were analyzed. Polar coordinate systems were introduced. Influencesof them to astronomical positioning and orientation were analyzed.7. Relationships of apparent star reference frames were researched. Differences of formerastronomical achievements were analyzed.