ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / This document is focused on the examination of the tracking angular error due to the radio refraction for the target in low altitude of less than 5km and in low elevation angle. The real measured data using the GPS and the tracking systems of C- and S-band frequency in NARO Space centre, Korea are used for the analysis. The analysis shows couple of conclusions on the radio refraction effects; there are angular errors due to the radio refraction which is not to be neglected comparing the accuracy of the tracking system but to be considered for the precise measurement of the target position. Also, the refraction errors are dependent on the target altitude, but not on the frequency.