Centimeter Level Orbit Determination for HY2A Using GPS Data

The first Chinese oceanographic satellite——HY2A was lanched on 16 August 2011 into a sun-synchronous orbit with an altitude of about 970 km.Precise orbit determination(POD) for HY2A is essential for the scientific applications of this mission.With the precision and navigation data analyst(PANDA) software,the precise orbits for HY2A are determined using only onboard GPS observations,meanwhile GPS data are used to model the consistent phase center offset(PCO) and phase center variation(PCV) of onboard receiver antenna.The orbit accuracy is assessed using a number of tests,which include analysis of observation residuals,orbit fits with CNES orbits,and satellite laser ranging residuals.The results show that 1~2 cm radial orbit accuracy for the HY2A has been achieved.These contributions could be used for continued low-earth orbiters(LEO) equipped indigenous onboard GPS receiver.