GLONASS common-view time transfer between North America and Europe and its comparison with GPS

GLONASS common-view time transfer between two North American Laboratories and the BIPM in France is in operation since June 1995. GLONASS time receivers, operating in these three locations, observe according to the 1st BIPM International GLONASS Common-View Schedule since 4 January 1996. As GPS common-view time transfer between Europe and North America is accomplished with an uncertainty of several nanoseconds, it gives here an excellent reference with which to evaluate the ultimate performance of GLONASS common-view time transfer. This comparison shows a slightly lower performance for GLONASS which is mainly due to very approximate evaluation of ionospheric delay for GLONASS observations and to limited possibilities to obtain accurate GLONASS ground antenna coordinates. In addition, the principles of developing a GLONASS common-view schedule are explained and some basic features of GLONASS time receivers are reported. Data processing and possible standardization of GLONASS international common-view time transfer are also discussed