Improvement of Time Comparison Results by using GPS Dual Frequency Codeless Receivers Measuring Ionospheric Delay

摘要

A dual frequency CPS receiver measuring ionospheric delay or TEC (Total Electron Content) named GTR-2 was constructed in BIPM (Bureau International des Poids et Mesures), and operates in regular base since October 1988. CRL (Communications Research Laboratory) also has completed a development of the same equipment this year. It has almost same performances as GTR-2 in BIPM. By using the two receivers, we have begun to compensate the time transfer results obtained from the conventional GPS time transfer receivers between Japan and Europe under the cooperation of CRL and BIPM for a construction of a tight time-transfer link by using GPS satellite. This paper shows the improvement of GPS time transfer results by using the ionospheric delays measured by GTR-2. For a highly transportable geodetic purpose VLBI (Very Long Baseline Interferometer) station, CRL has another application program of CTR-2. For this compact VLBI station, we are making a study of ionospheric compensation of the signal from radio stars by using the TEC data obtained from GTR-2.