Abstract: With the development of space-borne GPS technologies and IGS precise orbit and clock products,precise orbit determination(POD) of Low Earth Orbiters(LEOs) based on PPP technology has become a hot issue.At present,an accuracy of 3～5 cm in Radial(R),Along-track(T),Cross-track(N) components can be achieved with conventional PPP.However,the results are less precise or reliable than the double-differenced fixed solution due to the ambiguity-float solution in traditional PPP.In order to further improv...?More