Patent ID: 7840351

Claim:
A system for a precise orbit determination comprising: initial orbit determination unit for estimating an initial position of a Global Positioning System (GPS) satellite based on a GPS ephemeris provided from an International Global Navigation Satellite System Services (IGS) site and determining a position of a Low-Earth-Orbit (LEO) satellite based on navigation data of the LEO satellite; ionosphere error calculating and correcting unit for correcting an ionosphere error by: calculating a first total electron content (TEC) based on a combination of carrier phase data and pseudo range data in single frequency GPS data using a distance difference in time, finding a second TEC using an ionosphere model, adding the first TEC and the second TEC, and correcting the single frequency GPS data; preprocessing unit for double differencing ionosphere-free GPS data received at GPS observation stations and GPS data received at the LEO satellite to generate ionosphere-error-removed-observation-data; and orbit determination unit for determining an orbit by applying a GPS observation model the ionosphere-error-removed-observation-data, and estimating a position and a velocity of the LEO satellite through performing a filter algorithm on a difference from the GPS observation model and a dynamic perturbation model.