Abstract: To meet the need for precise orbit determination  POD  of the LEO satellites equipped with a single-frequency  SF  GPS receiver and deepen the research on POD with SF GPS data, the problem of cycle-slip detection for SF GPS data was solved, and the reduced-dynamic orbits for HY-2A satellite and ZY-3 satellite were determinated with two different approaches using the SF GPS observations. The precision of the derived orbits was assessed by the analysis of the observation residuals, comparison with the precise orbits derived from dual-frequency (DF) GPS data and validation with satellite laser ranging  SLR  measurements. The results indicate that the 3D precision of the SF orbit without ionospheric delay correction is between 2dm and 3dm for HY-2A and about 1m for ZY-3, and the notable improvement with the group and phase ionospheric correction GRAPHIC observation is achieved to eliminate the first order ionospheric delay and the 3D precision can reach 1dm for HY-2A and 1～2dm for ZY-3. The results demonstrate that the sub decimeter level accuracy can be achieved for POD of LEO equipped with a SF GPS receiver.

Key words: Single-frequency, Group and phase correction, Precise orbit determination, Low earth orbit