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Galileo system consists of 27 satellites distributed in three uniformly separated planes. At the end of 2005, one satellite,
Galileo In-Orbit Validation Element-A (GIOVE-A), was launched as planned into an MEO with an altitude of 23,260
kilometers. Carrying a payload of rubidium clocks, signal-generation units, and a phase-array antenna of individual
L-band elements. GIOVE-A started broadcasting on January 28, 2006, securing the frequencies allocated by the ITU for
Galileo. Performance of the on-board atomic clocks, antenna infrastructure, and signal properties is evaluated through
precise orbit determination, supported by Satellite Laser Ranging (SLR), an independent high-precision range
measurement technique for orbit determination based on a global network of stations that measure the round-trip
flight-time of ultra short laser pulses to satellites equipped with laser retro reflector arrays (LRAs). SLR provides
instantaneous range measurements of millimeter-level precision which can be compiled to provide accurate orbits and to
measure the on-board clock error. Given the importance of SLR data for the characterization of the GIOVE-A clocks, the
Changchun SLR station in northeast China was selected among the Chinese stations contributing to the ILRS because it
had demonstrated strong MEO satellite tracking; collocation with an existing International GPS Service station; and good
weather conditions. This paper introduces the SLR system improvement for tracking GIOVE-A satellite in Changchun
station. During the more than two months improvement, the new servo and encoder systems were installed, primary
mirror, second mirror and some other mirrors have been cleaned and recoated, and the laser system was adjusted in order
to improve the laser efficiency and output energy. The paper gives out the improvement results, and the GIOVE-A
satellite observation results.
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