A more direct iterative algorithm of the atmospheric bending angle in the retrieval of the earth's atmospheric parameters from radio occultation data of GPS/LEO satellites on non-circular orbits is presented. The convergence of this iterative method is mathematically proved. By using the simulative software package SHAOOS for the earth atmosphere retrieval from the GPS occultation observations, the effects of the circular orbit assumption on the retrieved atmospheric profiles are estimated quantitatively, and under the condition of non-circular orbits, the consistency of different iterative processes is verified. In addition, the shortage of a kind of iterative algorithm by means of series expansion is indicated.
