By using the IGS precise final orbit as a true orbit, long-term orbit and clock variations are analyzed. Orbit and
clock errors are computed for all GPS satellites and for the group of satellites visible in Korea. Orbit and clock
errors versus GPS satellite types are also analyzed. The orbit error variation period coincides with the GPS orbital
period. The radial orbit errors of the 2nd generation satellites are approximately two times greater than those of the
3rd generation satellites. The clock errors and SISRE decrease with the new generation of GPS satellites. The 3D
orbit error difference between global and Korea-only is 0.02m. The correlation analysis shows that the 3D orbit
errors in shadow are 3.2% higher than those in sunlight. Solar activity and orbit error have a high correlation until
2008, but they have a low correlation after 2009.