Real-time orbit determination of Low Earth orbit satellite based on RINEX/DORIS 3.0 phase data and spaceborne GPS data

High-precision of Low Earth orbit (LEO) satellite orbit is essential for some applications having real-time requirements, such as LEO navigation enhancement, real time scientific satellite research, and so on. Currently, more mature means for real-time orbit determination of LEO satellites rely on spaceborne GPS data and RINEX/DORIS 3.0 data. However, most researchers conduct experiments using spaceborne GPS data or RINEX/DORIS 3.0 data separately, and the experiment results from combining the two types of data simultaneously have not been obtained. Therefore, we evaluate simulated real-time orbit determination capability of using the RINEX/DORIS 3.0 phase observations and spaceborne GPS pseudo-range observations from the HY2A satellite in this paper. Since the 1-km precision of the RINEX/DORIS 3.0 pseudo-range observations are unfavorable for the initial orbit, the GPS pseudo-range areused for this computation. But, the RINEX/DORIS 3.0 phase observations are used to solve the real-time orbit of HY2A satellite. Our analysis results are: (1) the three-dimensional (3D) position accuracy of HY2A satellite calculated by the spaceborne GPS pseudo-range is 6.803 m, which meets the initial orbit positional accuracy requirement. The initial orbit velocity requirement can be met when the 5–7th-order Lagrangian interpolation method is used to solve the satellite velocity. The 3D-RMS values of the HY2A satellite velocity is smaller than 0.500 m/s, indicating the initial velocity accuracy requirement is satisfied. (2) After Kalman filter convergence, the agreement of the comparison with the CNES precise orbit shows better than 0.100 m in radial position, an RMS of 0.373 m in 3D total position, and an RMS of 0.374 mm/s in 3D total velocity. The results suggest that the radial position accuracy is better than 0.100 m, and could meet some HY2A altimetry applications. In the course of this study, a Fortran-based prototype real-time orbit determination system RTODLEO (Real-Time Orbit Determination Software for Low Earth Orbit Satellite) was developed and used for the analysis. The results from thirteen-day of real-time orbit determination also validate the RTODLEO software, and show it is reliable.