Study on Orbit Error Test of GPS Broadcasting Ephemeris

In recent years,GPS technology has been widely used in the fields of surveying,navigation and meteorology,but the accuracy and real-time for GPS satellite ephemeris have been requested to be improved.The method and steps for calculating GPS satellite orbit coordinate by means of KEPLERIAN orbit parameters in broadcasting ephemeris and correction quanta of orbit perturbation are sated in the text.The software of calculating GPS satellite orbit coordinate according to the broadcasting ephemeris is compiled and GPS satellite orbit coordinate is calculated in accordance with the practical data of broadcasting ephemeris.Then,the calculation results are compared with those of GPS satellite provided by IGS precise ephemeris every fifteen minutes and their orbit errors are discussed,and some conclusions of reference are drawn,which are of some practical significance for understanding GPS broadcasting ephemeris orbit accuracy and its influence on the accuracy of real-time orientation.