Abstract:The traditional dynamic orbit determination method is subject to the accuracy of the dynamic model. The traditional geometric orbit determination method has limited accuracy and can only reach the sub-meter level. The geometric orbit determination method based on the precise single-point positioning (PPP) mode generally uses floating point solutions. Orbit determination accuracy and reliability are worse than relative positioning based on the double-difference mode. In order to improve the positioning performance of low orbit determination in PPP mode, IGS stations inside and outside of China are used to calculate the phase deviation products of the wide and narrow lanes of all satellites. HY-2 and ZY-3 satellites over the Chinese mainland region perform fixed-ambiguity PPP fixed-orbit calculations, and compare them with ex-post precision orbit results to analyze their accuracy. The results show that using only the HY-2 and ZY-3 satellite data of the arc segment of about 10min, the tangential and tangential orbit determination accuracy can reach about 2cm and the normal direction is about 5cm, which greatly improves the accuracy of floating point solution orbit determination. The orbit determination method based on fixed ambiguity PPP can meet the real-time precise orbit determination of centimeter level.