Attitude determination of Galileo satellites using high-resolution kHz SLR

Galileo retroreflector panel was mounted on a tripod 32 km outside of the satellite laser ranging station Graz. The panel was tilted to achieve laser beam incident angles between 0^∘ and approx. 18^∘ while simultaneously doing distance measurements. At incident angles larger than approx. 8^∘ it was possible to identify fine structures within the data corresponding to the different columns of retroreflectors within the panel. The range differences between these columns were determined via a histogram analysis. Knowing the panel geometry it was possible to recalculate the laser beam incident angle on the panel. To compare these ground-based measurements to measurements to a specific pass of Galileo 103, matching incident angle conditions were chosen. Similar structures were found within the data set and it was possible to verify the incident angle of the laser beam. Such a method provides an excellent way to validate the attitude of Galileo satellites and is possible by analyzing the fine details of mm-accuracy kHz SLR data only.