Precise Determination of the new SLR Station of Shanghai Observatory

To merge the new SLR observation-station in Shanghai Astronomical Observatory into the federal operation of global SLR network,here the high-precision GPS positioning and accurate reduction to the mark center of the new SLR station using traditional optical-electronic observation equipments are performed according to the precision requirements of the fidncial stations in Chinese SLR observation network.A little special sliding centering cquipment is set on the SLR telescope to help find the real center of the vertical wheeling axes.which is based on the un-movement characteristics of the vertical wheeling axes wherever the telescope wheeling toward.After the vertical axes is found,the plane center is then determined according to the vertical distance from the reference point at the sliding centering equipment to the reference wheeling plane of the telescope.The whole surveying process is accomplished with three steps. First,set three reference points around the telescope,obtain their three-dimension coordinates in the ITRF at the observing epoch using three GPS receivers' observations linking to the IGS permanent station-SHAO.Second,using two total stations to get the plane coordinates and geodetic height based on the three ITRF coordinates and the agreement between the geodetic height difference and the leveling height difference in a small area.Combining the GPS precise engineering surveying technology and the traditional optical spatial direction intersection,we get a good result of three-dimension coordinate.The result indicates that the baseline's accuracy between the IGS SHAO and the mark center of the new SLR observation station is about 5 mm. the absolute positioning error related to the geo-eenter is about 10 mm while taking account into the accuracy of IGS SHAO in the ITRF.