?????????????VLBI???? VLBI Astrometric Observation of Spacecraft with phase delay

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?????????????VLBI????VLBI Astrometric
Observation of Spacecraft with phase delay

• ?? ?????????????????????(NICT)?
• ???(ISAS/JAXA)?????(???)?
• ???????VLBI??????
• (ISAS/JAXA?NICT?????????????????
• ?????????SGL,NRCan Canada)

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VLBI???????????????

• ??????????????????????????????????

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????? ?????????

• ???????????????? ?2?????????????????????

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??????????VLIB????VLBI???????? ????NiCT??????????
???????????????????????????
Algonquin SGL NRCan
Tomakomai (Hokkaido Univ.)
Mizusawa (NAO)
Usuda (ISAS)
Gifu (Gifu Univ.)
Tsukuba (GSI)
Yamaguchi (Yamaguchi Univ.)
Koganei (CRL)
Kashima (CRL)

Kagoshima(ISAS) (uplink)
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????????????VLBI ?????
???????????VLBI
???VLBI
(Fukuhisma 1993 AA)
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???????????????VLBI?????
?????? ??? (M.Eubanks 1991)
???? VLBI??? (Sekido Fukushima 2004)
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????

• C ??????????????
• ????????????CALC9 ???????.
• (Thanks to NASA/GSFC group)
• O????????????????? (tp)???.
• O-C???????????????

????
????
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??????(Post-fit ????)
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?????
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????
1280km
900km
500km
????????????????????????(24????)?????????? (June
4th experiments)
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?????????????????(?????)? ??(6?4????)
Tobs Nstn Nbase
6/4 26 h 7 21
???RRR ???????
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???

• ????????????????VLBI ???????
• ?????????????????????CALC9??????.
• 20????????????????????????.
• ??????????????????????RRR??????????????????????(?
  ??? ?????????????).
• ??????
• ????(Predicted orbit)??????????????
• ??VLBI???????????????????????????

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Space
Orbit of NOZOMI
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Group Delay(Range signal)
Closure
Observation mode 2MHz, 2bit
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Spacecraft Navigation with VLBI Motivation

• Required for increased accuracy for future space
  missions
• For landing, orbiting, saving energy
• JPL/NASA has been employed
• Japanese Space Agency (ISASNASDAJAXA)
• NOZOMI(Japanese Mars Explorer)
• Needs to support orbit determination with VLBI.
• Mission as our own Project

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Spacecraft Navigation
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ObservationIP-VLBI Sampler board
K5 VLBI System

• Sampling rate40k-16MHz
• Quantization bit 1-8bit
• 4ch/board
• 10MHz,1PPS inputs

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For astrometry of S.C.Tasks to be done are

• VLBI for Finite distance radio source
• A New VLBI delay Model corresponding to the
  CONSENSUS model.
• Narrow band width signal
• Group delay or Phase delay
• Delay Resolution (nano/pico seconds)
• Ambiguity problem
• Data Processing and Analysis software
• IP-sampler boards recording to HD
• Software correlation Analysis software

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SC coordinate solutiion with Group
Delay(Domestic Baselines)
Origin is determined orbit with RRR
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Phase delay solution
Obs. duration Nstn Nbase
May22 3.5 4 hours 6 15
May23 3.5 hours 5 10
May27 3 hours 4 6