The next-generation navigation system is proposed to incorporate Low Earth Orbit (LEO) satellites as an enhancement and backup. The theory and method of integrated Precise Orbit Determination (POD) of high, medium and low orbit satellites using ground station network and spaceborne GNSS receiver data is studied. A high-precision dynamic model and observation model are established, and the integrated POD experiments of navigation satellites and LEO satellites are carried out under the cases of global station and regional stations using real data. The results show that the integrated POD can obtain centimeter-level POD accuracy for both navigation satellites and LEO satellites simultaneously. As a high-dynamic space-based station, the LEO satellites can help improve the POD accuracy of navigation satellites by 20%~90%.