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Reviewing calibration results over the history since early 1980's among several labs shows very mixed results. The best stabilities of GPS receivers, as given by calibrations, are of the order of a few nanoseconds or better over a year, though many results are quite a bit worse. Absolute calibrations show similar potential, though there are problems. We conclude that more calibrations and standard...
Accurate GNSS (Global Navigation Satellite System) time transfer needs accurate satellite orbit information. Since Nov. 2009, the GLONASS time transfer is introduced in UTC generation. The precise and timely GLONASS orbit information is indispensable for Circular T computation. In this paper, we compare the GLONASS orbits produced by different analysis centers. We study the differences of the products,...
The CCTF CGGTTS data formats are used worldwide in the applications of various societies from the UTC/TAI production and scientific studies to all levels of commercial usages. Its design was based on the GPS receiver technique in the 1980s. With the progress of the new GNSS receivers and new T/F transfer techniques, its short points are becoming evident, e.g. the convention that for a tracking arc...
NTSC (National Time Service Center) is responsible for Chinese national time scale generation and has being applied TWSTFT (two-way satellite time and frequency transfer, TW for short) for time transfer since 1998. NTSC was one of the first UTC laboratories practicing TWSTFT in China. From 2002 to 2004, TWSTFT was the major technique for NTSC contributing to UTC. Since 2007, direct NTSC-European TWSTFT...
In this paper we report a new experiment of the combined use of GPS and GLONASS for international time and frequency transfer using TTS-3 multi-channel multisystem receivers. The investigation was carried out on a baseline of about 1400 km between the Astrogeodynamical Observatory (AOS) in Poland and Bureau International des Poids et Mesures (BIPM) in Sèvres. Unlike GPS, almost every GLONASS satellite...
Unlike GPS, the GLONASS P-code is broadly accessible. This paper discuss GLONASS capabilities and prospects in terms of precise time transfer. We have tested GLONASS common-view time transfer using the C/A- and P-code, over time links varying in length from about 800 km to 9200 km. The raw GPS and GLONASS data were collected using 3S navigation receivers, and were corrected using IGS precise orbit...
We present results from two calibrations performed in 2003 between the Global Positioning System (GPS) common-view receivers located at the National Institute of Standards and Technology (NIST) and at the Bureau National de Métrologie - Systèmes de Référence Temps Espace (BNM-SYRTE) of the Observatoire de Paris (OP) in the context of calibrations performed over 20 years, 1983–2003. We also present...
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