The paper discusses the position of the orbit of PRN11 GPS satellite. Visual analysis of the current GPS constellation showed considerable deviation of PRN11 GPS satellite orbital parameters relative to other orbital plane D satellites. Short comparison of available GPS almanac format was included. Two almanacs per year since the launch of the PRN11 satellites in 1999 were obtained. Parameters of right ascension of ascending node and rate of right ascension of ascending node were taken into investigation. The results confirmed the fact of constant and progressive separation of the orbit from home orbital plane D since the very beginning of the satellite mission. The simulation of long-term persistence of the current trend in the position of the PRN11 ascending node was presented.

DOI: https://doi.org/10.3846/enviro.2017.244