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78 results on '"Otsubo, Toshimichi"'

51. 月レーザ測距用ホロー型新規月面反射板の開発

Author

Araki, Hiroshi, Kashima, Shingo, Noda, Hirotomo, Kunimori, Hiroo, Chiba, Kota, Otsubo, Toshimichi, Utsunomiya, Shin, and Matsumoto, Yoshiaki

Abstract

第14回宇宙科学シンポジウム (2014年1月9日-10日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 14ｔh Space Science Symposium (January 9-10, 2014. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 資料番号: SA6000058190, レポート番号: P2-158

Published
2014

52. 月面コーナーキューブミラーの高精度製造方法検討(1)

Author

Kashima, Shingo, Araki, Hiroshi, Noda, Hirotomo, Hanada, Hideo, Kunimori, Hiroo, Otsubo, Toshimichi, Yasuda, Susumu, and Utsunomiya, Shin

Abstract

第14回宇宙科学シンポジウム (2014年1月9日-10日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 14ｔh Space Science Symposium (January 9-10, 2014. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 資料番号: SA6000058191, レポート番号: P2-159

Published
2014

53. Skew characteristics of image fiber for high-speed 2-D parallel optical data link

Author

Otsubo Toshimichi, Moriya Nakamura, and Ken-ichi Kitayama

Subjects
Optical fiber cable, Physics, Optical fiber, Bobbin, business.industry, Skew, Cladding (fiber optics), Atomic and Molecular Physics, and Optics, law.invention, Radius of curvature (optics), Optics, law, Parallel communication, business, Refractive index
Abstract

Skew of an image fiber, which has more than ten thousands of cores in a common cladding, was measured by a novel measurement method for the first time. This method can measure the time-of-flight difference between individual cores over the whole area of an image circle. The measurement result reveals that a test 100-m-long image fiber has skew of 5 ps/m, and the time-of-flight distributes randomly in the whole area of the image circle due to nonuniformity of the core dimension. It is also experimentally shown that the skew of an image fiber increases by bending. The theoretical analysis reveals that the bending-induced skew depends neither on the radius of curvature nor the shape of the curve but it depends only on the number of turns it is wound. The numerical calculation of skew by using typical parameters of image fibers shows that the winding have to be restricted to less than five turns to achieve a transmission speed of over 1 Gb/s/ch. Finally, we propose a twisted image fiber and an "8-shaped" bobbin to suppress the skew due to bending.

Published
2000
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54. cm精度で軌道を決める:地球を測る

Author

Otsubo, Toshimichi, 大坪 俊通, Otsubo, Toshimichi, and 大坪 俊通

Abstract

New technologies have made it possible to measure the satellite orbits at cm precision. Precise orbit determination software requires a number of physical models on the satellite acceleration, the rotation of the Earth, the site displacement, and so on. Reversely it can be used for detecting precise effects of cm or even sub-cm order., 近年の新しいテクノロジにより、人工衛星の軌道をcmで測定することが可能になっている。そのデータ解析を行う軌道決定ソフトウェアにおいては、衛星に作用する加速度・地球の回転・地上局の動きなど、数多くの物理モデルを取り込む必要がある。一方で、精密軌道決定を通して、cmあるいはmmオーダーの新たな物理現象を検出することも可能である。, JAXA Special Publication, 宇宙航空研究開発機構特別資料

Published
2015

55. GPSおよび超小型加速度計搭載小型衛星計画

Author

Fukuda, Yoichi, Tsuda, Toshitaka, Araya, Akito, Saito, Akinori, Kunimori, Hiroo, Otsubo, Toshimichi, Aoyama, Yuichi, 福田 洋一, 津田 敏隆, 新谷 昌人, 齋藤 昭則, 國森 裕生, 大坪 俊通, 青山 雄一, Fukuda, Yoichi, Tsuda, Toshitaka, Araya, Akito, Saito, Akinori, Kunimori, Hiroo, Otsubo, Toshimichi, Aoyama, Yuichi, 福田 洋一, 津田 敏隆, 新谷 昌人, 齋藤 昭則, 國森 裕生, 大坪 俊通, and 青山 雄一

Abstract

We propose a mission plan by means of a micro-satellite on a Low Earth Orbit (LEO) (300-1,000 km) with an advanced GPS (Global Positioning System) receiving system and a micro accelerometer on board. This LEO satellite can provide the following Earth observations: (1) time variations of low degrees Earth's gravity field coefficients; (2) fluctuations in atmospheric density in the thermosphere estimated from the atmospheric drags; (3) vertical structures of temperature, water vapor and electron density with GPS occultation technique; (4) the sea surface height and surface winds by receiving GPS reflection. The cost of this kind of small satellite is mush smaller than the ordinary earth observation satellites. Thus a large number of this kind of LEO satellites enables the low cost Earth's environments monitoring with high temporal and spatial resolutions in future.

Published
2015

57. 月レーザ測距用ホロー型逆反射板の材料選定及び重力・熱変形計算

Author

Araki, Hiroshi, Kashima, Shingo, Noda, Tomohiro, Kunimori, Hiroo, Otsubo, Toshimichi, Utsunomiya, Shin, Niwa, Yoshito, and Funazaki, Kenichi

Abstract

第13回宇宙科学シンポジウム (2013年1月8日-9日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 13th Space Science Symposium (January 8-9, 2013. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 資料番号: SA6000063290, レポート番号: P5-028

Published
2013

58. SELENE-2 月レーザ測距実験

Author

Noda, Tomohiro, Araki, Hiroshi, Katayama, Masato, Sasaki, Sho, Tazawa, Seiichi, Tsuruta, Seiitsu, Hanada, Hideo, Kunimori, Hiroo, Fuse, Tetsuharu, Otsubo, Toshimichi, Funazaki, Kenichi, Taniguchi, Hideo, and Murata, Kohei

Abstract

第12回宇宙科学シンポジウム (2012年1月5日-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県, 12th Space Science Symposium (January 5-6, 2012. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)Sagamihara Campus), Sagamihara, Kanagawa Japan, 著者人数: 13名, 資料番号: SA6000064145, レポート番号: P4-048

Published
2012

59. Feasibility evaluation of precise orbit determination system of ASTRO-G

Author

ASTROG技術実証チーム, Yoshihara, Keisuke, Asaki, Yoshiharu, Takeuchi, Hiroshi, Otsubo, Toshimichi, and ASTRO--G research team

Abstract

第11回宇宙科学シンポジウム (2011年1月5日-7日. 宇宙航空研究開発機構宇宙科学研究所相模原キャンパス), 相模原市, 神奈川県, 11th Space Science Symposium (January 5-7, 2011. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Sagamihara, Kanagawa Japan, 形態: カラー図版あり, 形態: CD-ROM1枚, Physical characteristics: Original contains color illustrations, Note: One CD-ROM, 資料番号: AA0065426112

Published
2011

60. 宇宙測地学的手法による火星回転変動計測

Author

Harada, Yuji, Iwata, Takahiro, Ishihara, Yoshiaki, Asari, Kazuyoshi, Araki, Hiroshi, Kikuchi, Fuyuhiko, Sasaki, Sho, Tsuruta, Seiitsu, Noda, Tomohiro, Hanada, Hideo, Sander, Goossens, Matsumoto, Koji, Aoyama, Yuichi, Imamura, Takeshi, Okubo, Shuhei, Otsubo, Toshimichi, Kono, Yusuke, Takano, Tadashi, Takeuchi, Hiroshi, Furuya, Masato, Heki, Kosuke, and Matsuo, Koji

Abstract

第24回大気圏シンポジウム（2010年2月18日-19日. 宇宙航空研究開発機構宇宙科学研究本部（JAXA)(ISAS)）, 相模原市, 神奈川県, 24th Atmospheric Science Symposium (February 18-19, 2010. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 22名, 資料番号: SA6000073045, レポート番号: Ⅴ-22

Published
2010

61. Plan for Lunar Laser Ranging (LLR) for the next lunar exploration SELENE-2

Author

Araki, Hiroshi, Noda, Hirotomo, Kunimori, Hiroo, Otsubo, Toshimichi, Katayama, Masato, Tazawa, Seiichi, Tsuruta, Seiitsu, Hanada, Hideo, Harada, Yuji, and Matsumoto, Koji

Abstract

第31回太陽系科学シンポジウム(2009年12月21-22日, 宇宙航空研究開発機構宇宙科学研究本部), The thirty-first Space Energy Symposium (December 21, 2009, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan), 形態: カラー図版あり, 形態: CD-ROM1枚, 著者人数: 11人, Physical characteristics: Original contains color illustrations, Note: One CD-ROM, 資料番号: AA0064738008

Published
2009

63. Accelerated ice mass depletion revealed by low-degree gravity field from satellite laser ranging: Greenland, 1991-2011

Author

Matsuo, Koji, Chao, Benjamin F., Otsubo, Toshimichi, 1000030280564, Heki, Kosuke, Matsuo, Koji, Chao, Benjamin F., Otsubo, Toshimichi, 1000030280564, and Heki, Kosuke

Abstract

We detect the acceleration of ice mass depletion in Greenland for the period 1991–2011 from the low-degree gravity field up to degree and order 4 derived from the Satellite Laser Ranging (SLR) data. Between 2003 and 2011, during the era when the GRACE (Gravity Recovery and Climate Experiment) satellite data are available, our SLR results of gravity changes agree well with GRACE showing significant negative patterns in Greenland. Prior to that, the SLR linear trend maps show a near balance in Greenland ice mass during 1991–2002 (after the glacial isostatic adjustment is accounted for using model values). We further confirm the consistency of our SLR results with the vertical crustal uplift of the region observed by the Global Positining System (GPS) which manifests ice mass loading/unloading. Thus, the SLR data series constitute a continuous benchmark for the time history of the Greenland ice mass changes for over two decades.

Published
2013

64. Image fiber skew characteristics

Author

Otsubo Toshimichi, Moriya Nakamura, and Ken-ichi Kitayama

Subjects
Optical fiber, Bobbin, business.industry, Numerical analysis, Skew, Curvature, Cladding (fiber optics), law.invention, Radius of curvature (optics), Optics, law, business, Refractive index, Mathematics
Abstract

Skew of an image fiber, which has more than ten thousands of cores in a common cladding, was measured by a novel measurement method for the first time. This method can measure the time-of-flight difference between individual cores over the whole area of an image circle. The measurement results reveals that a test 100-m-long image fiber has skew of 5 ps/m, and the time-of-flight distributes randomly in the whole area of the image circle due to nonuniformity of the core dimension. It is also experimentally shown that the skew of an image fiber increases by bending. The theoretical analysis reveals that the bending-induced skew depends neither on the radius of curvature nor the shape of the curve but it depends only on the number of turns it is wound. The numerical calculation of skew by using typical parameters of image fibers shows that the winding have to be restricted to less than 12.5 turns to achieve a transmission speed of over 1 Gbps/ch. Lastly we propose twisted image fiber and a 8-shaped bobbin to suppress the skew due to bending.

Published
2000
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65. Asymmetric dihedral angle offsets for large-size lunar laser ranging retroreflectors

Author

1000070358943, Otsubo, Toshimichi, Kunimori, Hiroo, Noda, Hirotomo, Hanada, Hideo, Araki, Hiroshi, Katayama, Masato, 1000070358943, Otsubo, Toshimichi, Kunimori, Hiroo, Noda, Hirotomo, Hanada, Hideo, Araki, Hiroshi, and Katayama, Masato

Abstract

The distribution of two-dimensional velocity aberration is off-centered by 5 to 6 microradians in lunar laser ranging, due to the stable measurement geometry in the motion of the Earth and the Moon. The optical responses of hollow-type retroreflectors are investigated through numerical simulations, especially focusing on large-size, single-reflector targets that can ultimately minimize the systematic error in future lunar laser ranging. An asymmetric dihedral angle offset, i.e. setting unequal angles between the three back faces, is found to be effective for retroreflectors that are larger than 100 mm in diameter. Our numerical simulation results reveal that the optimized return energy increases approximately 3.5 times more than symmetric dihedral angle cases, and the optimized dihedral angle offsets are 0.65-0.8 arcseconds for one angle, and zeroes for the other two angles.

Published
2011

74. Spin Axis Precession of LARES Measured by Satellite Laser Ranging.

Author

Kucharski, Daniel, Lim, Hyung-Chul, Kirchner, Georg, Otsubo, Toshimichi, Bianco, Giuseppe, and Hwang, Joo-Yeon

Abstract

Satellite laser ranging (SLR) is an efficient technique to measure spin parameters of the fully passive satellite LARES. Analysis of the laser range measurements gives information about the spin rate of the spacecraft and the orientation of its spin axis. A frequency analysis applied to the SLR data indicates an exponential increase of the satellite's spin period: T = 11.7612 \cdot \exp (0.00293327 \cdot D), \RMS = 0.115\ \s, where D is in days since launch. The initial spin period of LARES is calculated from the spin observations during the first 30 days after launch and is equal to T0 = 11.7131, \RMS = 0.073\ \s. The spin axis of the satellite is precessing around the initial coordinates of right ascension \RAinitial = 186.5^\circ, \RMSRA = 3.1^\circ, and \Declination Decinitial = - 73.0^\circ, \RMSDec = 0.7^\circ (J2000 inertial reference frame), with a period of 211.7 days. The precession of the spin axis may be responsible for the observed oscillation of the slowing down rate: the spin half-life period (the time after which the spin period has doubled) varies between 209 and 267 days. The measured spin parameters of LARES are compared—and show good agreement—with the theoretical predictions given by the satellite spin model. Information about the spin parameters of LARES is necessary for the accurate modeling of the forces and torques that are affecting the orbital motion of the satellite. [ABSTRACT FROM PUBLISHER]

Published
2014
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78. The Impact of Solar Irradiance on AJISAI's Spin Period Measured by the Graz 2-kHz SLR System.

Author

Kucharski, Daniel, Kirchner, Georg, Otsubo, Toshimichi, and Koidl, Franz

Subjects
ARTIFICIAL satellites, MAGNETIC fields, GRAVITATIONAL fields, SOLAR energy, ASTRONOMICAL perturbation, REMOTE sensing
Abstract

The Graz kHz Satellite Laser Ranging (SLR) system is the first system operating with a 2-kHz-repetition-rate laser. Using Graz 2-kHz SLR data only, we applied a new analytical approach to determine the spin period of the passive satellite AJISAI. This method analyzes the range measurements to the single corner-cube-reflector panels of AJISAI, allowing accurate determination of an actual attitude of this satellite during day and night. Using Graz kHz SLR data of more than five years, we processed 877 passes of AJISAI (October 9, 2003-December 22, 2008) and calculated its spin period (∼2 s) with an accuracy of 0.0042% (84 μs). This spin period (T ) is increasing, following an exponential trend: T = 1.9028 · Exp (0.014859 · (Year - 2003.0)) s. This slow down is mainly caused by the gravitational andmagnetic fields of the Earth. The high accuracy allows, for the first time, the detection of small perturbations of the spin period caused by nongravitational effects related to the solar energy flux to which the satellite is exposed. [ABSTRACT FROM AUTHOR]

Published
2010
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