29 / 2015-08-25 23:29:19

RESEARCH ON THE FITTING ALGORITHM OF GLONASS BROADCAST EPHEMERIS PARAMETERS

The accuracy of GLONASS broadcast ephemeris data accumulated error is nearly 1 meters within 15 minutes due to simplified perturbation force model. Aiming at this problem, a new method of GLONASS broadcast ephem-eris fitting algorithm is introduced. In this method, a non-linear measurement model is built based on the GLONASS broadcast ephemeris user algorithm and linear-ized. And the partial derivative of Jacobin matrix is com-puted by difference quotient approximation. Then the GLONASS broadcast ephemeris parameters are estimated by using least square method. The simulation results show that the average user range error (URE) caused by fitting GLONASS broadcast ephemeris is improved about two orders compared with the traditional GLONASS broadcast ephemeris and achieves millimeter level. Finally, a verifi-cation system of GLONASS broadcast ephemeris was built, and using the Japanese RTKLIB tools, the availabil-ity of the fitting broadcast ephemeris is validated from the positioning angle.