Short-term analysis of internal and external CORS clocks

Abstract

AbstractThe International GNSS Service (IGS) provides high-accuracy clock products for both GNSS satellites and stations. On board of each GNSS satellite are located 3–4 atomic oscillators. In the case of CORS oscillators, the majority of them are equipped with internal oscillators and a part uses external, high-rate clocks. In the IGS network there are four types of external oscillators: quartz, rubidium, caesium and H-maser. These CORS are often reference stations for precise GNSS measurements or for time transfer. In this paper the author provides analyses of the internal and external stability of the reference stations oscillators via the usage of Allan variations. The results show a strong advantage of the external clocks over internal ones by about five orders of magnitude.