Dept. of Spacecraft Engineering

Shin-ichiro Sakai

  (坂井 真一郎)

Profile Information

Affiliation
Professor, Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
Degree
博士(工学)(Mar, 2000, 東京大学)

Researcher number
10342619
J-GLOBAL ID
202101019944115931
researchmap Member ID
R000018454

External link

Major Research Interests

 2

Major Papers

 82
  • Kambayashi Masaru, Ito Takahiro, Sakai Shinichiro
    Transactions of the Japan Society for Aeronautical and Space Sciences, 67(1) 23-31, Jan 4, 2024  Peer-reviewed
  • Toyota Hiroyuki, Miyazawa Yu, Kanaya Shusaku, Kukita Akio, Kondo Hiroatsu, Koide Kazuya, Kuhara Takahiro, Nakamura Kazuyuki, Kawano Taro, Naito Hitoshi, Sawai Shujiro, Fukuda Seisuke, Sakai Shinichiro
    Transactions of the Japan Society for Aeronautical and Space Sciences, 66(6) 199-208, Nov 4, 2023  Peer-reviewed
  • Cetiny Mustafa Efe, Soken Halil Ersin, Sakai Shinichiro
    The Journal of the Astronautical Sciences, 69 1726-1743, Nov 11, 2022  Peer-reviewed
  • 植田聡史, 伊藤琢博, 坂井真一郎
    計測自動制御学会論文集, 58(3) 194-201, Apr 7, 2022  Peer-reviewed
  • Shibata Takuma, Sakai Shinichiro
    JOURNAL OF SPACECRAFT AND ROCKETS, 59(2) 651-659, Mar 29, 2022  Peer-reviewed
  • Ito Takahiro, Sakai Shinichiro
    JOURNAL OF GUIDANCE, CONTROL, AND DYNAMICS, 46(4) 695-708, Feb 1, 2022  Peer-reviewed
  • Takahashi Yuta, Sakamoto Hiraku, Sakai Shin-ichiro
    Journal of Guidance, Control, and Dynamics, 45(2) 280-295, Feb 1, 2022  Peer-reviewed
  • Satoshi UEDA, Takahiro ITO, Shinichiro SAKAI
    Transactions of the Society of Instrument and Control Engineers, 58(3) 194-201, 2022  
  • Ueda Satoshi, Sakai Shin-ichiro
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 19(3) 334-343, May 4, 2021  Peer-reviewed
  • 柴田 拓馬, 坂井 真一郎
    日本航空宇宙学会論文集, 69(2) 60-67, Apr 5, 2021  Peer-reviewed
  • Daijiro Shiraiwa, Nobuhiko Tanaka, Kohei Kojima, Takao Kaneko, Shinichiro Sakai, Kenichi Kushiki, Shujiro Sawai, Keisuke Michigami, Taro Kawano, Kenta Goto, Katsumi Furukawa
    Proceedings of the International Astronautical Congress, IAC, C4, 2021  
    In this paper, we introduce the 500N class bipropellant ceramic thruster for SLIM (Smart Lander for Investigating Moon). It has three main features. The first is a silicon nitride ceramic chamber. It is the only one used by MHI. Second, it has a wide operating range and provides stable performance. It can perform blowdown operation without requiring a high-pressure gas tank. The third activity is Pulse firing which is considered difficult in 500N class thrusters, is possible.
  • Go Fujii, Kaname Kawatsu, Yu Daimon, Keisuke Michigami, Kenichi Kushiki, Shujiro Sawai, Shinichiro Sakai
    AIAA Propulsion and Energy Forum, 2021, 2021  
    SLIM (Smart Lander for Investigating Moon) is JAXA’s new lunar lander mission under development. The system firing test was conducted to acquire experimental data of transient behavior of propellant pressure in order to verify the requirement for the propulsion system design and the simulation model, using real propellants and the flight like model of SLIM propulsion system. We observed three remarkable phenomena, which are (1) wide frequency distribution in pressure fluctuation, (2) water hammer when the main engine’s valves are closed, and (3) cross talking. From the evaluation of test results and the combination with simulation, we understood the physical phenomena with real propellants and the flight like model. As a result, we concluded that the current design of SLIM propulsion system is compatible to all the requirements and the expected operational mode of SLIM.
  • Ito Takahiro, Sakai Shin-ichiro
    Journal of Guidance, Control, and Dynamics, 44(4) 854-861, Dec 1, 2020  Peer-reviewed
  • Ito Takahiro, Sakai Shin-ichiro
    Acta Astronautica, 176(6) 438-454, Nov 1, 2020  Peer-reviewed
    © 2020 IAA Onboard computation of a fuel-optimal trajectory is an indispensable technology for future lunar and planetary missions with pinpoint landings. This paper proposes a throttled explicit guidance (TEG) scheme under bounded constant thrust acceleration. TEG is capable of achieving fuel-optimal large diversions with good accuracy and can find optimal solutions. Thus far, the TEG algorithm is unique as it offers an explicit and simultaneous search method for the fuel-optimal thrust direction and thrust magnitude switching in predictor-corrector iterations. Fast numerical search is realized with a straightforward computation of seven final states (position, velocity, and the Hamiltonian) from seven unknowns (six adjoint variables for position and velocity and one final time). In addition, global convergence capability is enhanced by implementing the damped Newton's method. A number of simulations of large diversions show the excellent convergence of the TEG algorithm within at most 15 iterations from a cold start. The experimental results of the runtime measurement of the TEG algorithm support its real-time feasibility on a flight processor. These features of the TEG are suitable for onboard guidance of pinpoint landings.
  • Ikari Satoshi, Ito Takahiro, Oguri Kenshiro, Inamori Takaya, Sakai Shinichiro, Kawakatsu Yasuhiro, Tomiki Atsushi, Funase Ryu
    JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 68(2) 89-95, Aug 1, 2020  Peer-reviewed
    <p>A Fault Detection, Isolation, and Recovery (FDIR) algorithm for attitude control systems is a key technology to increasing the reliability and survivability of spacecraft. Micro/nano interplanetary spacecraft, which are rapidly evolving in recent years, also require robust FDIR algorithms. However, the implementation of FDIR algorithms to these micro/nano spacecraft is difficult because of the limitations of their resources (power, mass, cost, and so on). This paper shows a strategy of how to construct a FDIR algorithm in the limited resources, taking examples from micro deep space probe PROCYON. The strategy focuses on function redundancies and multi-layer FDIR. These ideas are integrated to suit the situation of micro/nano interplanetary spacecraft and demonstrated in orbit by the PROCYON mission. The in-orbit results are discussed in detail to emphasize the effectiveness of the FDIR algorithm. </p>
  • Soken Halil Ersin, Sakai Shin-ichiro, Asamura Kazushi, Nakamura Yosuke, Takashima Takeshi, Shinohara Iku
    Aerospace, 7(97) 97-97, Jul 1, 2020  Peer-reviewed
    JAXA’s ERG (Exploration of Energization and Radiation in Geospace) Spacecraft, which is nicknamed Arase, was launched on 20 December 2016. Arase is a spin-stabilized and Sun-oriented spacecraft. Its mission is to explore how relativistic electrons in the radiation belts are generated during space storms. Two different on-ground attitude determination algorithms are designed for the mission: A TRIAD-based algorithm that inherits from old missions and a filtering-based new algorithm. This paper, first, discusses the design of the filtering-based attitude determination algorithm, which is mainly based on an Unscented Kalman Filter (UKF), specifically designed for spinning spacecraft (SpinUKF). The SpinUKF uses a newly introduced set of attitude parameters (i.e., spin-parameters) to represent the three-axis attitude of the spacecraft and runs UKF for attitude estimation. The paper then presents the preliminary attitude estimation results for the spacecraft that are obtained after the launch. The results are presented along with the encountered challenges and suggested solutions for them. These preliminary attitude estimation results show that the expected accuracy of the fine attitude estimation for the spacecraft is less than 0.5°.
  • Soken Halil Ersin, Sakai Shin-ichiro
    ISA Transactions, Sep 1, 2019  Last author
  • 柴田 拓馬, 坂井 真一郎
    日本航空宇宙学会論文集, 67(4) 126-135, Aug 1, 2019  Last author
  • Mitani Shinji, Mizutani Tadahito, Sakai Shin-ichiro
    DESIGN AND DEVELOPMENT OF FIBER OPTIC ROTATION SENSORS, 113-124, Jul 1, 2019  
  • 新井 久旺, 坂井 真一郎
    日本航空宇宙学会論文集, 67(3) 81-92, Jun 1, 2019  Last author
  • Nakamura Yosuke, Fukuda Seisuke, Shibano Yasuko, Ogawa Hiroyuki, Sakai Shin-ichiro, Shimizu Shigehito, Soken Halil Ersin, Miyazawa Yu, Toyota Hiroyuki, Kukita Akio, Maru Yusuke, Nakatsuka Junichi, Sakai Tomohiko, Takeuchi Shinsuke, Maki Kenichiro, Mita Makoto, Ogawa Emiko, Kakehashi Yuya, Nitta Kumi, Asamura Kazushi, Takashima Takeshi, Shinohara Iku
    Earth, Planets and Space, 70(1) 102, Dec 1, 2018  
    The exploration of energization and radiation in geospace (ERG) satellite, nicknamed "Arase," is the second satellite in a series of small scientific satellites created by the Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency. It was launched on December 20, 2016, by the Epsilon launch vehicle. The purpose of the ERG project is to investigate how high-energy (over MeV) electrons in the radiation belts surrounding Earth are generated and lost by monitoring the interactions between plasma waves and electrically charged particles. To measure these physical processes in situ, the ERG satellite traverses the heart of the radiation belts. The orbit of the ERG is highly elliptical and varies due to the perturbation force: the apogee altitude is approximately 32,200-32,300 km, and the perigee altitude is 340-440 km. In this study, we introduce the scientific background for this project and four major challenges that need to be addressed to effectively carry out this scientific mission with a small satellite: (1) dealing with harsh environmental conditions in orbit and electromagnetic compatibility issues, (2) spin attitude stabilization and avoiding excitation of the libration by flexible structures, (3) attaining an appropriate balance between the mission requirements and the limited resources of the small satellite, and (4) the adaptation and use of a flexible standardized bus. In this context, we describe the development process and the flight operations for the satellite, which is currently working as designed and obtaining excellent data in its mission.
  • Ito Takahiro, .Ikari Satoshi, Funase Ryu, Sakai Shin-ichiro, Kawakatsu Yasuhiro, Tomiki Atsushi, Inamori Takaya
    Acta Astronautica, 152 299-309, Nov 1, 2018  
    © 2018 IAA This study proposes a solar sailing method for angular momentum control of the interplanetary micro-spacecraft PROCYON (PRoximate Object Close flYby with Optical Navigation). The method presents a simple and facile practical application of control during deep space missions. The developed method is designed to prevent angular momentum saturation in that it controls the direction of the angular momentum by using solar radiation pressure (SRP). The SRP distribution of the spacecraft is modeled as a flat and optically homogeneous plate at a shallow sun angle. The method is obtained by only selecting a single inertially fixed attitude with a bias-momentum state. The results of the numerical analysis indicate that PROCYON's angular momentum is effectively controlled in the desired directions, enabling the spacecraft to survive for at least one month without momentum-desaturation operations by the reaction control system and for two years with very limited fuel usage of less than 10 g. The flight data of PROCYON also indicate that the modeling error of PROCYON's SRP distribution is sufficiently small at a small sun angle (<10°) of the order of 10−9 Nm in terms of its standard deviation and enables the direction of the angular momentum around the target to be maintained.
  • 石井晴之, 村田暁紀, 上野史, 辰巳嵩豊, 梅内祐太, 高玉圭樹, 原田智広, 鎌田弘之, 石田貴行, 福田盛介, 澤井秀次郎, 坂井真一郎
    航空宇宙技術(Web), 17 69-78, May 1, 2018  
  • 植田 聡史, 坂井 真一郎, 福田 盛介, 澤井 秀次郎
    計測と制御, 57(4) 222-228, Apr 1, 2018  
  • Satoshi UEDA, Takahiro ITO, Takehiro HIGUCHI, Seiya UENO, Shinichiro SAKAI
    AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 17 45-54, Mar 1, 2018  
  • SAWAI Shujiro, OKAZAKI Shun, KUKITA Akio, MIYAZAWA Yu, UEDA Satoshi, TOBE Hirobumi, MARU Yusuke, SHIMOJI Haruhiko, SHIMIZU Yasuhiro, SHIBASAKI Yusuke, SHIMADA Sadanori, FUKUDA Seisuke, YOKOI Takahiro, YABUSHITA Takeshi, SATO Kenichiro, NAKAMURA Kazuyuki, KUHARA Takahiro, TAKAMI Tsuyoshi, TANAKA Nobuhiko, FURUKAWA Katsumi, SAKAI Shinichiro, KUSHIKI Kenichi, ARAKAWA Tetsuhito, SATO Eiichi, TOMIKI Atsushi, MICHIGAMI Keisuke, KAWANO Taro
    AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 17 35-43, Mar 1, 2018  
    <p>SLIM (Smart Lander for Investigating Moon) is the Lunar Landing Demonstrator which is under development at ISAS/JAXA. SLIM demonstrates not only so-called Pin-Point Landing Technique to the lunar surface, but also demonstrates the design to make the explorer small and lightweight. Realizing the compact explorer is one of the key points to achieve the frequent lunar and planetary explorations. This paper summarizes the preliminary system design of SLIM, especially the way to reduce the size.</p>
  • 岡田怜史, 中浜優佳, 森部美沙子, 鎌田弘之, 狩谷和季, 高玉圭樹, 石田貴行, 福田盛介, 澤井秀次郎, 坂井真一郎
    航空宇宙技術(Web), 17 61-67, Mar 1, 2018  
  • Ryo HIRASAWA, Toshinori IKENAGA, Satoshi UEDA, Shinichiro SAKAI
    AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 17 1-9, Jan 1, 2018  Last author
  • Shuichi Sato, Seiji Kawamura, Masaki Ando, Takashi Nakamura, Kimio Tsubono, Akito Araya, Ikkoh Funaki, Kunihito Ioka, Nobuyuki Kanda, Shigenori Moriwaki, Mitsuru Musha, Kazuhiro Nakazawa, Kenji Numata, Shin-ichiro Sakai, Naoki Seto, Takeshi Takashima, Takahiro Tanaka, Kazuhiro Agatsuma, Koh-suke Aoyanagi, Koji Arai, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka, Toshiyuki Morisawa, Shinji Mukohyama, Shigeo Nagano, Isao Naito, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Norio Okada, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Rieko Suzuki, Hideyuki Tagoshi, Fuminobu Takahashi, Kakeru Takahashi, Keitaro Takahashi, Ryutaro Takahashi, Ryuichi Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Yasuo Torii, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Yaka Wakabayashi, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun’ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino
    Journal of Physics: Conference Series, 840(1) 012010-012010, May, 2017  Peer-reviewed
  • Halil Ersin Soken, Shin-ichiro Sakai, Kazushi Asamura, Yosuke Nakamura, Takeshi Takashima
    SPACEFLIGHT MECHANICS 2017, PTS I - IV, 160 2615-2629, 2017  
    When quaternions are used for representing the attitude of a spinning spacecraft in an attitude estimation filter, several problems appear due to their rapid variations. These problems include numerical integration errors and violation of the linear approximations for the filter. In this study, we propose representing the attitude of a spinning spacecraft using a set of spin parameters. These parameters consist of the spin-axis orientation unit vector in the inertial frame and the spin phase angle. This representation is advantageous as the spin axis direction components in the inertial frame do not change rapidly and the phase angle changes with a constant rate in the absence of a torque. The attitude matrix and the kinematics equations are derived in terms of spin parameters. As the equations are highly nonlinear an Unscented Kalman Filter (UKF) is implemented to estimate the spacecraft's attitude in spin parameters. The estimation results are compared with those of a quaternion based UKF in different scenarios using the simulated data for JAXA's ERG spacecraft.
  • Satoshi Ikari, Takaya Inamori, Takahiro Ito, Kaito Ariu, Kenshiro Oguri, Masataka Fujimoto, Shinichiro Sakai, Yasuhiro Kawakatsu, Ryu Funase
    Transactions of the Japan Society for Aeronautical and Space Sciences, 60(3) 181-191, 2017  
    © 2017 The Japan Society for Aeronautical and Space Sciences. This paper describes development strategies and on-orbit results of the attitude determination and control system (ADCS) for the world's first interplanetary micro-spacecraft, PROCYON, whose advanced mission objectives are optical navigation or an asteroid close flyby. Although earth-orbiting micro-satellites already have ADCSs for practical missions, these ADCSs cannot be used for interplanetary micro-spacecraft due to differences in the space environments of their orbits. To develop a new practical ADCS, four issues for practical interplanetary micro-spacecraft are discussed: initial Sun acquisition without magnetic components, angular momentum management using a new propulsion system, the robustness realized using a fault detection, isolation, and recovery (FDIR) system, and precise attitude control. These issues have not been demonstrated on orbit by interplanetary micro-spacecraft. In order to overcome these issues, the authors developed a reliable and precise ADCS, a FDIR system without magnetic components, and ground-based evaluation systems. The four issues were evaluated before launch using the developed ground-based evaluation systems. Furthermore, they were successfully demonstrated on orbit. The architectures and simulation and on-orbit results for the developed attitude control system are proposed in this paper.
  • Satoshi Ikari, Takaya Inamori, Takahiro Ito, Kaito Ariu, Kenshiro Oguri, Masataka Fujimoto, Shinichiro Sakai, Yasuhiro Kawakatsu, Ryu Funase
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 60(3) 181-191, 2017  
    This paper describes development strategies and on-orbit results of the attitude determination and control system (ADCS) for the world's first interplanetary micro-spacecraft, PROCYON, whose advanced mission objectives are optical navigation or an asteroid close flyby. Although earth-orbiting micro-satellites already have ADCSs for practical missions, these ADCSs cannot be used for interplanetary micro-spacecraft due to differences in the space environments of their orbits. To develop a new practical ADCS, four issues for practical interplanetary micro-spacecraft are discussed: initial Sun acquisition without magnetic components, angular momentum management using a new propulsion system, the robustness realized using a fault detection, isolation, and recovery (FDIR) system, and precise attitude control. These issues have not been demonstrated on orbit by interplanetary micro-spacecraft. In order to overcome these issues, the authors developed a reliable and precise ADCS, a FDIR system without magnetic components, and ground-based evaluation systems. The four issues were evaluated before launch using the developed ground-based evaluation systems. Furthermore, they were successfully demonstrated on orbit. The architectures and simulation and on-orbit results for the developed attitude control system are proposed in this paper.
  • TAKINO Tatsuya, NOMURA Izuru, MORIBE Misako, KAMATA Hiroyuki, TAKADAMA Keiki, FUKUDA Seisuke, SAWAI Shujiro, SAKAI Shin-ichiro
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 14(30) Pt_7-Pt_14, 2016  
    <p>In this study, a crater detection method for a moon-landing system with low computational resources is proposed. The proposed method is applied to the Smart Lander for Investigating Moon (SLIM), which aims for a pin-point landing on the moon. According to this plan, surface images of the moon will be captured by a camera mounted on the space probe, and the craters are to be detected from the images. Based on the positional relationship between detected craters, the method estimates the exact flight position of the space probe. Because the computational resources of SLIM are limited, rapid and accurate crater detection must be performed using fixed-point arithmetic on a field-programmable gate array (FPGA). This study proposes a crater detection method that uses principal component analysis (PCA). The computational processing for crater detection by PCA is performed by product-sum operations, which are suitable for fixed-point arithmetic. Moreover, this method is capable of parallel processing; hence high-speed processing is expected. This study not only introduces a crater detection method using PCA but also evaluates the properties of this method.</p>
  • Kikuchi Masao, Ishikawa Takehiko, Yamamoto Shin, Sawai Shujiro, Maru Yusuke, Sakai Shinichiro, Bando Nobutaka, Shimizu Shigehito, Kobayashi Hiroaki, Yoshimitsu Tetsuo, Kan Yuji, Mizushima Takanari, Fukuyama Seijiro, Okada Junpei, Yoda Shinichi, Fuke Hideyuki, Kakehashi Yuya, Hashimoto Tatsuaki
    INTERNATIONAL JOURNAL OF MICROGRAVITY SCIENCE AND APPLICATION, 32(2), 2015  Peer-reviewed
    A microgravity experiment system using a high altitude balloon has been developed. In order to accommodate payloads larger than previous system which employed three- dimensional drag-free control, one-dimensional drag-free control has been applied. The first test flight was conducted in Aug. 2014. A gravity level below 10(-3) G was obtained for more than 30 seconds during the free-fall of the capsule. A combustion experiment was conducted during the low gravity condition.
  • BANDO Nobutaka, FUKE Hideyuki, SHOJI Yasuhiro, DOETINCHEM Philip v., HAILEY Charles J., SAKAI Shin-ichiro, HASHIMOTO Tatsuaki
    SPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 14 59-65, 2015  
    In this paper, direction control of balloon gondola with only untwisting motor is proposed. Typically a reaction wheel and another actuator for unloading the reaction wheel are in use to control the attitude (or direction) of the gondola. Although this method can get high accuracy control performance, two actuators spend many resources of the gondola. The proposed method uses only untwisting motor installed above the gondola to rotate. This method can not realize such high accuracy control performance but realize direction control with the most simple configuration. The proposed method is applied to prototype GAPS (General Anti-Particle Spectrometer) balloon experiment in 2012. This paper shows control design for this experiment and the results of the proposed method.
  • Shinji Mitani, Yasuhiro Kawakatsu, Shin-ichiro Sakai, Naomi Murakami, Toshihiko Yamawaki, Tadahito Mizutani, Keiji Komatsu, Hirokazu Kataza, Keigo Enya, Takao Nakagawa
    SPACE TELESCOPES AND INSTRUMENTATION 2014: OPTICAL, INFRARED, AND MILLIMETER WAVE, 9143, 2014  
    SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is an astronomical mission optimized for mid-and far-infrared astronomy with a 3-m class telescope which is cryogenically cooled to be less than 6 K. The SPICA mechanical cooling system is indispensable for the mission but, generates micro-vibrations which could affect to the pointing stability performances. Activities to be undertaken during a risk mitigation phase (RMP) include consolidation of micro-vibration control design for the satellite, as well as a number of breadboarding activities centered on technologies that are critical to the success of the mission. This paper presents the RMP activity results on the micro-vibration control design.
  • T. Kotani, K. Enya, T. Nakagawa, H. Matsuhara, H. Kataza, M. Kawada, M. Mita, K. Komatsu, H. Uchida, K. Fujiwara, S. Mitani, S. Sakai, K. Haze, H. Kaneda, S. Oyabu, D. Ishihara, T. Miyata, S. Sako, T. Nakamura, K. Asano, M. Tamura, J. Nishikawa, T. Yamashita, N. Narita, H. Hayano, S. Oya, E. Kokubo, Y. Itoh, T. Matsuo, M. Fukagawa, H. Shibai, M. Honda, N. Baba, N. Murakami, Y. K. Okamoto, S. Ida, M. Takami, L. Abe, O. Guyon, T. Yamamuro
    SPACE TELESCOPES AND INSTRUMENTATION 2012: OPTICAL, INFRARED, AND MILLIMETER WAVE, 8442, 2012  
    We present the current status of the development of the SPICA Coronagraph Instrument (SCI). SPICA is a next-generation 3-meter class infrared telescope, which will be launched in 2022. SCI is high-contrast imaging, spectroscopic instrument mainly for direct detection and spectroscopy of extra-solar planets in the near-to-mid infrared wavelengths to characterize their atmospheres, physical parameters and evolutionary scenarios. SCI is now under the international review process. In this paper, we present a science case of SCI. The main targets of SCI, not only for direct imaging but also for spectroscopy, are young to matured giant planets. We will also show that some of known exoplanets by ground-based direct detection are good targets for SCI, and a number of direct detection planets that are suitable for SCI will be significantly increased in the next decade. Second, a general design of SCI and a key technology including a new high-throughput binary mask coronagraph, will be presented. Furthermore, we will show that SCI is potentially capable of achieving 10(-6) contrast by a PSF subtraction method, even with a telescope pointing error. This contrast enhancement will be important to characterize low-mass and cool planets.
  • NAGAMATSU Hiroyuki, ASAMURA Kazushi, YAMAZAKI Atsushi, SAKAI Shin-ichiro, FUKUDA Seisuke, SAITO Hirobumi
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN, 10(28) Pf_15-Pf_19, 2012  
    We are in progress to develop a system for automatic operation of a satellite in order to reduce human load at satellite steady operation phase. The ground station for small satellite REIMEI (INDEX : INnovative-technology Demonstration EXperiment) is used as a test bench for verification of the proposed method. In our new automatic operation system, a scheduler software as a substitutive operator manages all the operations through a unified procedure, including sending command, receiving telemetry, and driving antenna in accordance with an operation time line which is prepared before the operation pass. The scheduler also performs diagnostics of satellite anomaly based upon the received telemetry data and status of the ground station. In case that some anomaly of the satellite is detected, the scheduler initiates an emergency schedule that was prepared depending on the emergency level. The automatic operation system is nearly completed for downlink operations of the data recorder that account for 75% of REIMEI steady operation. This approach is very effective to reduce psychological and physical load of operators.
  • NAKAYA Koji, FUKUDA Seisuke, SAKAI Shin-ichiro, YAMAZAKI Atsushi, UEMIZU Kazunori, TORIUMI Tsuyoshi, Junko TAKAHASHI, MAEHARA Masaki, OKAHASHI Takakazu, SHUJIRO SAWAI And
    Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan (Web), 10(ists28), 2012  
  • K. Enya, T. Kotani, K. Haze, K. Aono, T. Nakagawa, H. Matsuhara, H. Kataza, T. Wada, M. Kawada, K. Fujiwara, M. Mita, S. Takeuchi, K. Komatsu, S. Sakai, H. Uchida, S. Mitani, T. Yamawaki, T. Miyata, S. Sako, T. Nakamura, K. Asano, T. Yamashita, N. Narita, T. Matsuo, M. Tamura, J. Nishikawa, E. Kokubo, Y. Hayano, S. Oya, M. Fukagawa, H. Shibai, N. Baba, N. Murakami, Y. Itoh, M. Honda, B. Okamoto, S. Ida, M. Takami, L. Abe, O. Guyon, P. Bierden, T. Yamamuro
    Advances in Space Research, 48(2) 323-333, Jul 15, 2011  
    We present the SPICA Coronagraphic Instrument (SCI), which has been designed for a concentrated study of extra-solar planets (exoplanets). SPICA mission provides us with a unique opportunity to make high contrast observations because of its large telescope aperture, the simple pupil shape, and the capability for making infrared observations from space. The primary objectives for the SCI are the direct coronagraphic detection and spectroscopy of Jovian exoplanets in infrared, while the monitoring of transiting planets is another important target. The specification and an overview of the design of the instrument are shown. In the SCI, coronagraphic and non-coronagraphic modes are aplicable for both an imaging and a spectroscopy. The core wavelength range and the goal contrast of the coronagraphic mode are 3.5-27 μm, and 10 , respectively. Two complemental designs of binary shaped pupil mask coronagraph are presented. The SCI has capability of simultaneous observations of one target using two channels, a short channel with an InSb detector and a long wavelength channel with a Si:As detector. We also give a report on the current progress in the development of key technologies for the SCI. © 2011 COSPAR. Published by Elsevier Ltd. All rights reserved. 31. -6
  • NAKAMURA Tsutomu, BANDO Nobutaka, SAKAI Sin-ichiro, SAITO Hirobumi
    JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 58(682) 309-315, Nov 5, 2010  
    A radio astronomical observatory satellite ``ASTRO-G'', which will be launched in 2012, has two characteristics: flexible appendages and high-speed and high-precision attitude maneuvering. Because of these two antithetical features, attitude control system (ACS) of ASTRO-G becomes quite challenging in comparison with those of past satellites. For such a satellite, feedforward control which is robust to model identification error is considered to be important. Nil-Mode-Exciting (NME) profiler is one of references for anti-vibration, which is designed to excite no flexible modes, and thus its robustness is considered to be of most significant. NME profiler, however, is relatively slow reference because of negligible high frequency component. In this paper, we propose Modified NME profiler which is relatively fast reference designed by convolution of NME profiler and Input Shaper. Some anti-vibration experiments are carried out to show the effectiveness of the proposed reference.
  • ANDO Masaki, KAWAMURA Seiji, SATO Shuichi, NAKAMURA Takashi, TSUBONO Kimio, ARAYA Akito, FUNAKI Ikkoh, IOKA Kunihito, KANDA Nobuyuki, MORIWAKI Shigenori, MUSHA Mitsuru, NAKAZAWA Kazuhiro, NUMATA Kenji, SAKAI Shin-ichiro, SETO Naoki, TAKASHIMA Takeshi, TANAKA Takahiro, DECIGO Working Group the
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN, 8(27) Po_4_1-Po_4_6, 2010  
    A space gravitational wave antenna, DECIGO (DECI-hertz interferometer Gravitational wave Observatory) will provide fruitful insights into the universe, particularly on dark energy, the formation mechanism of supermassive black holes, and the inflation of the universe. In the current pre-conceptual design, DECIGO will be comprised of 4 interferometer units; each interferometer unit will be realized by formation flight of three drag-free spacecraft with 1000 km separation. Since DECIGO will be an extremely challenging mission with high-precision formation flight, it is important to increase the technical feasibility before its planned launch in 2024. Thus, we are planning two milestone missions. DECIGO pathfinder (DPF) is the first milestone mission for DECIGO, and key components for DPF are being tested on ground and in orbit. In this article, we review the conceptual design and current status of DECIGO and DPF.
  • SAITO Hirobumi, SAKAI Shin-ichiro, HIGUCHI Ken, KISHIMOTO Naoko, TAKEUCHI Hiroshi, YOSHIHARA Keisuke, ASAKI Yoshiharu, TSUBOI Masato, MURATA Yasuhiro, KOBAYASHI Hideyuki
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 8(27) To_4_33-To_4_41, 2010  Peer-reviewed
    Space VLBI (very long baseline interferometry) mission, ASTRO-G, will be launched in 2013 by Japan Aerospace Exploration Agency (JAXA). ASTRO-G is a follow-on mission of HALCA (VSOP) mission in 1990s, which was the world first space VLBI mission. ASTRO-G will consists of a huge synthetic aperture with diameter of 35,000 Km together with radio antennas in the ground. They will achieve the world highest angular resolution imaging by means of 43 GHz observation. This paper describes the advanced key technologies of ASTRO-G such as the 9 m deployable antenna with very accurate surface, the fast rest - to - rest attitude maneuver, and the precision orbit determination above NAVSTAR&#039;s orbits. These advance technologies lead ASTRO-G mission to the astronomical observation with the world highest angular resolution.
  • Peter J. Buist, Sandra Verhagen, Tatsuaki Hashimoto, Shujiro Sawai, Shin-ichiro Sakai, Nobutaka Bando, Shigehito Shimizu
    2010 IEEE-ION POSITION LOCATION AND NAVIGATION SYMPOSIUM PLANS, 1287-1294, 2010  Peer-reviewed
    JAXA has been developing a system to provide a long duration, good quality microgravity environment based on a capsule, named the Balloon-based Operation Vehicle, that can be released from a balloon. In this paper we will describe the Balloon-based operation vehicle itself and the experiments using GPS performed - in cooperation with Delft University of Technology - on the gondola of the balloon in 2008 (single baseline estimation) and 2009 (full attitude determination and relative positioning). The attitude calculated using raw observations from a GPS receiver during the 2009 experiment is compared with Sun Aspect Sensors' and Geomagnetic Aspect Sensor's results and moreover with the attitude as provided by the receiver itself.
  • Masaki Ando, Seiji Kawamura, Shuichi Sato, Takashi Nakamura, Kimio Tsubono, Akito Araya, Ikkoh Funaki, Kunihito Ioka, Nobuyuki Kanda, Shigenori Moriwaki, Mitsuru Musha, Kazuhiro Nakazawa, Kenji Numata, Shin-ichiro Sakai, Naoki Seto, Takeshi Takashima, Takahiro Tanaka, Kazuhiro Agatsuma, Koh-suke Aoyanagi, Koji Arai, Hideki Asada, Yoichi Aso, Takeshi Chiba, Toshikazu Ebisuzaki, Yumiko Ejiri, Motohiro Enoki, Yoshiharu Eriguchi, Masa-Katsu Fujimoto, Ryuichi Fujita, Mitsuhiro Fukushima, Toshifumi Futamase, Katsuhiko Ganzu, Tomohiro Harada, Tatsuaki Hashimoto, Kazuhiro Hayama, Wataru Hikida, Yoshiaki Himemoto, Hisashi Hirabayashi, Takashi Hiramatsu, Feng-Lei Hong, Hideyuki Horisawa, Mizuhiko Hosokawa, Kiyotomo Ichiki, Takeshi Ikegami, Kaiki T. Inoue, Koji Ishidoshiro, Hideki Ishihara, Takehiko Ishikawa, Hideharu Ishizaki, Hiroyuki Ito, Yousuke Itoh, Nobuki Kawashima, Fumiko Kawazoe, Naoko Kishimoto, Kenta Kiuchi, Shiho Kobayashi, Kazunori Kohri, Hiroyuki Koizumi, Yasufumi Kojima, Keiko Kokeyama, Wataru Kokuyama, Kei Kotake, Yoshihide Kozai, Hideaki Kudoh, Hiroo Kunimori, Hitoshi Kuninaka, Kazuaki Kuroda, Kei-ichi Maeda, Hideo Matsuhara, Yasushi Mino, Osamu Miyakawa, Shinji Miyoki, Mutsuko Y. Morimoto, Tomoko Morioka, Toshiyuki Morisawa, Shinji Mukohyama, Shigeo Nagano, Isao Naito, Kouji Nakamura, Hiroyuki Nakano, Kenichi Nakao, Shinichi Nakasuka, Yoshinori Nakayama, Erina Nishida, Kazutaka Nishiyama, Atsushi Nishizawa, Yoshito Niwa, Taiga Noumi, Yoshiyuki Obuchi, Masatake Ohashi, Naoko Ohishi, Masashi Ohkawa, Norio Okada, Kouji Onozato, Kenichi Oohara, Norichika Sago, Motoyuki Saijo, Masaaki Sakagami, Shihori Sakata, Misao Sasaki, Takashi Sato, Masaru Shibata, Hisaaki Shinkai, Kentaro Somiya, Hajime Sotani, Naoshi Sugiyama, Yudai Suwa, Rieko Suzuki, Hideyuki Tagoshi, Fuminobu Takahashi, Kakeru Takahashi, Keitaro Takahashi, Ryutaro Takahashi, Ryuichi Takahashi, Tadayuki Takahashi, Hirotaka Takahashi, Takamori Akiteru, Tadashi Takano, Keisuke Taniguchi, Atsushi Taruya, Hiroyuki Tashiro, Yasuo Torii, Morio Toyoshima, Shinji Tsujikawa, Yoshiki Tsunesada, Akitoshi Ueda, Ken-ichi Ueda, Masayoshi Utashima, Yaka Wakabayashi, Hiroshi Yamakawa, Kazuhiro Yamamoto, Toshitaka Yamazaki, Jun'ichi Yokoyama, Chul-Moon Yoo, Shijun Yoshida, Taizoh Yoshino
    CLASSICAL AND QUANTUM GRAVITY, 26(9), May, 2009  
    DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), which is a future space gravitational wave antenna. DECIGO is expected to provide fruitful insights into the universe, particularly about dark energy, the formation mechanism of supermassive black holes and the inflation of the universe. Since DECIGO will be an extremely challenging mission, which will be formed by three drag-free spacecraft with 1000 km separation, it is important to increase the technical feasibility of DECIGO before its planned launch in 2024. Thus, we are planning to launch two milestone missions: DPF and pre-DECIGO. In this paper, we review the conceptual design and current status of the first milestone mission, DPF.
  • HASHIMOTO Tatsuaki, SAWAI Shujiro, SAKAI Shin'ichiro, BANDO Nobutaka, KOBAYASHI Hiroaki, ISHIKAWA Takehiko, INATOMI Yuko, FUJITA Kazuhisa, YOSHIMITSU Tetsuo, SAITO Yoshitaka, FUKE Hideyuki
    JASMA, 26(1) 9-14, Jan 31, 2009  
  • SAWAI Shujiro, HASHIMOTO Tatsuaki, SAKAI Shinichiro, BANDO Nobutaka, YOSHIMITSU Tetsuo, ISHIKAWA Takehiko, INATOMI Yuko, FUKE Hideyuki, KAMATA Yukio, NAGAE Tomoko, KOBAYASHI Hiroaki, FUJITA Kazuhisa, KOJIMA Takayuki, UENO Seiya, MIYAJI Kouji, KADOOKA Shohei, HIRAKI Kouju, SUZUKI Koujiro, UEHARA Satoshi
    JASMA, 26(1) 21-28, Jan 31, 2009  
  • FUKUDA Seisuke, MIZUNO Takahide, SAKAI Shin-ichiro, FUKUSHIMA Yousuke, SAITO Hirobumi
    JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 57(660) 25-31, Jan 5, 2009  
    REIMEI/INDEX (INnovative-technology Demonstration EXperiment) is a 70kg class small satellite which the Institute of Space and Astronautical Science, Japan Exploration Agency, ISAS/JAXA, has developed for observation of auroral small-scale dynamics as well as demonstration of advanced satellite technologies. An important engineering mission of REIMEI is integrated satellite control using commercial RISC CPUs with a triple voting system in order to ensure fault-tolerance against radiation hazards. Software modules concerning every satellite function, such as attitude control, data handling, and mission applications, work cooperatively so that highly sophisticated satellite control can be performed. In this paper, after a concept of the integrated satellite control is introduced, the Integrated Controller Unit (ICU) is described in detail. Also unique topics in developing the integrated control system are shown.
  • Takaaki TANAKA, Takashi KIDA, Tomoyuki NAGASHIO, Takashi OHTANI, Isao YAMAGUCHI, Tokio KASAI, Yoshiro HAMADA, Shin-ichiro SAKAI, Nobutaka BANDO
    Journal of Space Engineering, 2(1) 12-24, 2009  
  • Tetsuo Yoshimitsu, Shujiro Sawai, Takahide Mizuno, Seisuke Fukuda, Nobutaka Bando, Shin'ichiro Sakai, Ken Higuchi, Tatsuaki Okada, Takashi Kubota, Daisuke Kobayashi, Ryoichiro Yasumitsu, Makoto Kunugi, Shoji Yoshikawa, Katsumi Furukawa, Tetsuya Matsuo
    60th International Astronautical Congress 2009, IAC 2009, 2 1096-1100, 2009  Peer-reviewed
    After the success of remotely-sensed global observation by SELENE orbiter, Japan has been focusing on the in-situ exploration of the Moon. To know more about the Moon, numerous missions have to be launched to the Moon for surveying different interesting places. Naturally the cost of single mission must be reduced. Japan has been considering a landing mission for about ten years as a next mission to the Moon. This has a few tons of weight and costs a few million euros including the launch vehicle because it also features the future manned mission. Obviously it is not suitable for scientific in-situ exploration, which must be conducted repeatedly. The authors have been studying a small lander on the Moon or the planets in order to enable the multiple in-situ explorations cheaply. With the technologies developed in our studies, the mission named SLIM (Smart Lander for Investigating Moon) has been proposed to demonstrate an autonomous, accurate and soft landing on the specified place of the Moon. SLIM is also helpful to increase the success probability of the nation-led flagship landing mission when it is conducted as a precursor. This paper describes the proposed SLIM mission.
  • Tatsuaki Hashimoto, Shujiro Sawai, Shin'ichiro Sakai, Nobutaka Bando, Hiroaki Kobayashi, Kazuhisa Fujita, Yuko Inatom, Takehiko Ishikawa, Tetsuo Yoshimitsu, Yoshitaka Saito
    60th International Astronautical Congress 2009, IAC 2009, 1 IAC-09.A2.5.3-730, 2009  Peer-reviewed
    To provide long duration and good quality of micro-gravity environment with moderate cost, we proposed and have been developed an experiment system that is released from a high altitude balloon. The experiment system has a double-shell drag-free structure and it is controlled not to collide with the inner shell to realize good quality of micro-gravity environment. This paper shows the configuration of the experiment system and summarizes its five-year development including three flight test results. The fist stage of the development was successfully completed this year. The next step is micro-gravity fall with engine for longer duration of experiment. Another direction of the development is real operation of the system for micro-gravity scientists. Those future plans are also described.
  • ISHIKAWA Takehiko, HASHIMOTO Tatsuaki, SAWAI Shujiro, SAITO Yoshitaka, INATOMI Yuko, YOSHIMITSU Tetsuo, SAKAI Shin'ichiro, KOBAYASHI Hiroaki, FUJITA Kazuhisa, BANDO Nobutaka
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 7(26) Ph_29-Ph_33, 2009  
    The second flight of microgravity experiment system using a free fall capsule from a high altitude balloon was conducted in May 2007. Using a drag free control, around 10-4G gravity conditions were obtained for 30 seconds. Results of a combustion experiment with Japanese sparker conducted inside the microgravity experimental unit were also reported.
  • SAWAI Shujiro, FUJITA Kazuhisa, KOBAYASHI Hiroaki, SAKAI Shin'ichiro, BANDO Nobutaka, KADOOKA Shouhei, TSUBOI Nobuyuki, MIYAJI Koji, UCHIYAMA Taku, HASHIMOTO Tatsuaki
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 7(26) Tg_27-Tg_34, 2009  
    JAXA is developing Mach 5 hypersonic turbojet engine technology that can be applied in a future hypersonic transport. Now, Jet Engine Technology Research Center of JAXA conducts the experimental study using a 1 / 10 scale-model engine. In parallel to engine development activities, a new supersonic flight-testing vehicle for the hypersonic turbojet engine is under development since 2004. In this paper, the system configuration of the flight-testing vehicle is outlined and development status is reported.
  • SAITO Hirobumi, SAWAI Syujiro, SAKAI Shin-ichiro, FUKUDA Seisuke, KITADE Kenji
    Acta Astronautica, 65(9/10), 2009  
  • 福田盛介, 澤井秀次郎, 坂井真一郎, 齋藤宏文, 遠間孝之, 高橋純子, 鳥海強, 北出賢二
    宇宙技術(Web), 8, 2009  
  • ISHIKAWA Takehiko, INATOMI Yuko, HASHIMOTO Tatsuaki, SAWAI Shujiro, SAITO Yoshitaka, YOSHIMITSU Tetsuo, SAKAI Shin'ichiro, KOBAYASHI Hiroaki, FUJITA Kazuhisa, BANDO Nobutaka, GOTO Masayuki
    JASMA, 25(1) 3-10, Jan 31, 2008  
  • 金田良介, 坂井真一郎, 橋本樹明, 齋藤宏文
    日本航空宇宙学会論文集, 56(652) 203-210 (J-STAGE)-210, 2008  Peer-reviewed
    For astronomical observing missions by formation flying satellites in LEO, satellites require control force to keep the relative position, against Keplerian orbit in an inertia coordinate frame. Since satellites require propulsion systems, i.e. thrusters, but the use of thrusters limits the mission lifetime associated with the finite fuel supply. Thus the authors propose the formation flight using electromagnetic force. In this method, the electromagnetic force between super-conducting magnets are used for the relative position control. This method has the obvious advantage of no-fuel to acquire control force. Since such large magnetic moment in earth magnetism generates large disturbance torque, the magnetic moments should be sinusoidal with shorter period than that of the orbit period. Therefore, this paper proposes the relative position control by changing the phase difference between sinusoidal magnetic moments. The proposed method was evaluated with numerical simulations and the results shows the feasibility of the proposed formation flight.
  • 澤井秀次郎, 橋本樹明, 坂井真一郎, 坂東信尚, 小林弘明, 藤田和央, 吉光徹雄, 石川毅彦, 稲富裕光, 福家英之, 鎌田幸男, 星野慎二, 田島賢一, 門岡昇平, 上原聡, 小島孝之, 上野誠也, 宮路幸二, 坪井伸幸, 平木講儒, 鈴木宏二郎, 松嶋清穂, 中田孝
    日本航空宇宙学会論文集, 56(654), 2008  
  • INATOMI Yuko, ISHIKAWA Takehiko, HASHIMOTO Tatsuaki, SAWAI Shujiro, SAITO Yoshitaka, YOSHIMITSU Tetsuo, SAKAI Shin-ichiro, KOBAYASHI Hiroaki, FUJITA Kazuo, BANDO Nobutaka, GOTO Masayuki, JIMBO Itaru, YAMAKAWA Hiroshi
    JASMA, 24(3) 296-300, Jul 30, 2007  
  • Maeda K, Tohma T, Saitoh T, Hara Y, Mitsuda K, Dotani T, Maeda Y, Ishida M, Kokubun M, Kunieda H, Hashimoto T, Sakai S
    Proceedings of the SICE Annual Conference, 3019-3024, 2007  Peer-reviewed
  • INATOMI Yuko, ISHIKAWA Takehiko, HASHIMOTO Tatsuaki, SAWAI Shujiro, SAITO Yoshitaka, YOSHIMITSU Tetsuo, SAKAI Shin-ichiro, KOBAYASHI Hiroaki, FUJITA Kazuhisa, BANDO Nobutaka, GOTO Masayuki, JIMBO Itaru, YAMAKAWA Hiroshi
    JASMA, 23(4) 197-203, Nov 30, 2006  
  • INATOMI Yuko, JIMBO Itaru, ISHIKAWA Takehiko, HASHIMOTO Tatsuaki, SAWAI Shujiro, SAITO Yoshitaka, YOSHIMITSU Tetsuo, SAKAI Shin-ichiro, KOBAYASHI Hiroaki, FUJITA Kazuhisa, BANDO Nobutaka, GOTO Masayuki, YAMAKAWA Hiroshi
    23(4) 280-280, Nov 30, 2006  
  • INATOMI Y., BANDO N., SAWAI S., ISHIKAWA T., SAKAI S., YOSHIMITSU T., SAITO Y., YAMAKAWA H., HASHIMOTO T.
    22(4) 317-317, Nov 28, 2005  
  • SAKAI Shin-ichiro, FUKUSHIMA Yosuke, HOMMA Takayuki, KANEDA Ryosuke, NAGAO Tsuyoshi
    The IEICE transactions on communications B, 88(1) 69-78, Jan 1, 2005  
  • HASHIMOTO Tatsuaki, SAITO Yoshitaka, INATOMI Hiromitsu, ISHIKAWA Takehiko, SAWAI Shujiro, YAMAKAWA Hiroshi, YOSHIMITSU Tetsuo, SAKAI Shin'ichiro
    21 66-66, Nov 4, 2004  

Misc.

 19

Major Presentations

 229

Research Projects

 5