Wettzell 測地観測所訪問

一橋大学で重力測定が行われているころ,12月14-15日,大坪はドイツにて Wettzell 測地観測所を訪問しました.3つの VLBI アンテナ,2つの SLR 望遠鏡,さらに DORIS, Ring Laser, GNSS, 重力計など,多数の宇宙測地観測装置が集積されているところです.数多くの専門家のみなさんと議論・情報交換ができました.



講演報告: Special Seminar, AIUB, Switzerland

On 12 Dec 2016, Otsubo visited the Zimmerwald Optical Ground Station to see its SLR, GNSS and space debris tracking facility, and later visited the Astronomical Institute of the University of Bern (AIUB) where he presented “SLR station network: for the near future and the far future” in AIUB Special Seminar. We appreciate the opportunity and the warm hospitality.



服部晃久,大坪俊通 「測地衛星の表面材質と太陽輻射圧係数」


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SLR Station Performance Charts: July 2015 to June 2016

T Otsubo hosted one of the ‘clinic’ session booths during the 20th International Workshop on Laser Ranging in Potsdam.   It covers both quantity and quality aspects of SLR stations.  The following are the links to the charts.

Hit-rate (observation success rate) over all fly-over observation chances (El > 20 deg)
(Pages 3 and 5 are just rescaled-without-Yarragadee version of Pages 2
and 4 resp)

LAGEOS-1+2 NP Post-POD RMS vs Session-by-session system delay RMS
(Page 1 >> ZOOM >> Page 2 >> ZOOM >> Page 3)

System delay time series
(1 year span)
(5 day span; one of densely observed periods)

System delay measurement frequency
= Interval between calibration record with different time tags
(blue parts: not a unique measurement? Identical records with different time tags found.)
(X-axis extended for 1824, 1873, 1884 and 7820)

Range residual vs System delay

Range residual vs Intensity (# of returns per NP)

Range residual vs Single-shot RMS

Range residual vs Sun Elevation (day vs night)

Toshimichi Otsubo <t.otsubo@r.hit-u.ac.jp> and Akihisa Hattori
Hitotsubashi University

20th International Workshop on Laser Ranging in Potsdam



  • Otsubo, A. Hattori, M. Kobayashi, M. Wilkinson, J. Rodriguez, Detection of various SLR systematic errors for mm accuracy, 20th International Workshop on Laser Ranging, 2016.10.12.
  • Otsubo, K. Matsuo, K. Yamamoto, Y. Aoyama, T. Hobiger, T. Kubo-oka, M. Sekido, Satellite laser ranging network: Where should a new station be placed?, 20th International Workshop on Laser Ranging, 2016.10.10.


  • Otsubo, M. Wilkinson, C. Potter, T. Shoobridge, J. Griffiths, Time series of SpinSat return intensity: How long can BK7 reflectors survive in space?, 20th International Workshop on Laser Ranging, 2016.10.11.


さらに,Clinic Session (少人数ローテーションセッション)のブース担当,1つのセッションの座長,1つの併設会議の座長を行うことになっており,忙しい1週間になりそうです.


なお,この会議の第18回は日本の富士吉田市で行われました.ウェブサイトは本研究室にまだ残っています → http://geo.science.hit-u.ac.jp/lw18/

講演報告: UCL Zibart Laboratory

8月19日(金)は University College London (UCL) の Ziebart 研究室を訪問し,午後には本学での SLR 関係の研究を紹介してきました.

UCL キャンパス内には Japan Garden という区画があり,そこにあった碑がこちら.近代日本を創った方々が 1863-1865 ころ集中的に UCL に滞在したようで,一橋大学の森有礼さんの名も. Photo: Prof M Ziebart


Ajisai 30th birthday

The Japanese Geodetic Satellite “Ajisai” was launched on 13 August 1986 in JST (12 August in UTC), and it has just reached 30 years old.  It has revolved around the Earth for more than 130000 times, and it is still being used.

JAXA has released the anniversary article: http://fanfun.jaxa.jp/topics/detail/8240.html (in Japanese only)

This has been one of the most frequently tracked satellites among a number of laser ranging targets.  Just 6 hours before it became 30, at 14:03 UTC, 12 Aug 2016, the satellite was tracked by the UK Herstmonceux laser ranging system.

This satellite was designed and manufactured nicely.  It has significantly contributed to geodesy, mapping, and space engineering, and it will be so in the future.

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Video & Photo: CP & TO.