Institute of Space and Astronautical Science (ISAS)
NEC Corporation
National Astronomical Observatory
Institute of Space and Astronautical Science (ISAS)
NEC Corporation
Institute of Space and Astronautical Science (ISAS)
Institute of Space and Astronautical Science (ISAS)
Institute of Space and Astronautical Science (ISAS)
The phase transfer to the space VLBI（Very Long Baseline Interferometry）satellite HALCA and the instrument system for it on board the spacecraft aredescribed. The phase transfer, supplying an extremely stable frequency-referencesignal to spacecraft by a radio wave from ground, is one of the key technologiesnecessary for space VLBI. The phase transfer for HALCA consists of such operations as:（1）a ground station transmits a 15.3 GHz up-link signal generated from a hydrogen maser frequency standard to the spacecraft,（2）a phase-lock receiver on the spacecraft receives the 15.3 GHz signal and generates the reference signal with a frequency of 50 MHz,（3）the reference signal is supplied to the radio astronomy instruments and the local signal generator,（4）the local signal generator generates a 14.2 GHz down-link carrier, together with local frequency signals for radio astronomy receivers,（5）the 14.2 GHz down-link carrier, which is QPSK modulated by radio astronomy signals, is transmitted toward ground, and（6）the down-link carrier is received and demodulated, and two-way loop phase is measured, at the ground station. The system on board the spacecraft has been confirmed, before the launch, to satisfy the coherence condition required from the VLBI correlation. The phase transfer has operated satisfactorily for the satellite HALCA in orbit and contributed to the success of the space VLBI observations by HALCA.
科学衛星「はるか」における位相基準信号伝送のための衛星搭載システム
SA0200045.pdf
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