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Multiple spacecraft formation forms a distributed space system where multiple spacecraft cooperatively exhibit the functionality of a single monolithic spacecraft or work in a cooperative way towards the completion of a common goal. This possibility of distributing the workload between different spacecraft provides the ability to work in parallel, enable economic and simple solutions in terms of spacecraft design, while is redundant towards partial or complete failure of a spacecraft. Some of the challenges, associated to the guidance and control aspects of the spacecraft formation, are to maintain a safe separation distance between each spacecraft in the formation to avoid any collision, the distribution of workload between the spacecraft group, and designing fuel efficient trajectories for each spacecraft. This thesis focuses on studying these challenges through two respective mission scenarios, a) the co-location of geostationary satellites, and b) the cooperative visual coverage of an asteroid. The first part of the thesis covers the development of guidance and control strategies to co-locate multiple geostationary satellites safely with a single operational slot. This part of the research is motivated by the growing demand to access the limited Earth resource of geostationary region; the growing use of low-thrust electric propulsion systems for geostationary satellite platforms; and the use of the same propulsion system for station keeping and momentum management of the reaction wheels to maintain a nadir pointing attitude for the satellites. Thus, to address the concurrent maneuver planning problem, a convex-optimization-based algorithm is proposed that incorporates a dual-rate prediction model to address the time scaling difference between the coupled slow orbital and fast attitude dynamics. The use of a combined prediction model in the optimization problem facilitates to include state constraints accounting for the desired orbital and momentum unloading requ

Dynamics of rapid changes of intensity and structure in an eyewall replacement cycle of tropical cyclones remain an open question. To clarify the dynamics of the inner eyewall decaying, a quantitative estimation of inner-core wind fields based on highly frequent observation images with 2.5-min temporal resolution in the Himawari-8 satellite is applied to Typhoon Trami (2018) which had a clear concentric eyewall structure. A high tangential wind of 50 m s(-1) is estimated at a radius of 30 km, which is located in the inner edge of the inner eyewall, during an active stage of the inner eyewall. During the decaying stage of the inner eyewall, the estimated tangential wind rapidly decreases to about 20 m s(-1) at a radius of 24 km. The satellite-based tangential winds are validated with dropsondes around the inner core by an aircraft. Vorticity field retrieved by the satellite-based tangential winds during the decaying stage exhibits a rapid decrease in an outer part of the eye and the inner eyewall, and a slow decrease near the storm center. Examination on an absolute angular momentum coordinate indicates that the rapidly slow-down rotation in the outer edge of the eye and inner eyewall is faster than a slow-down rotation explained by surface friction. It suggests that asymmetric eddies transport angular momentum across the moat in the inner eyewall dissipation. This study is the first examination of dynamical contributions of asymmetric eddies to the inner-eyewall dissipation based on satellite-estimated tangential winds. Plain Language Summary Intense tropical cyclones often have the concentric secondary eyewall outside the original (primary) eyewall enclosing the eye (i.e., concentric eyewalls; CEs). The primary eyewall tends to decay after the secondary eyewall formation (i.e., eyewall replacement cycle; ERC). Dynamics of rapid changes of intensity and structure in an ERC remain an open question. To clarify the dynamics of the inner eyewall decaying, a quantitative

Dynamics of rapid changes of intensity and structure in an eyewall replacement cycle of tropical cyclones remain an open question. To clarify the dynamics of the inner eyewall decaying, a quantitative estimation of inner-core wind fields based on highly frequent observation images with 2.5-min temporal resolution in the Himawari-8 satellite is applied to Typhoon Trami (2018) which had a clear concentric eyewall structure. A high tangential wind of 50 m s(-1) is estimated at a radius of 30 km, which is located in the inner edge of the inner eyewall, during an active stage of the inner eyewall. During the decaying stage of the inner eyewall, the estimated tangential wind rapidly decreases to about 20 m s(-1) at a radius of 24 km. The satellite-based tangential winds are validated with dropsondes around the inner core by an aircraft. Vorticity field retrieved by the satellite-based tangential winds during the decaying stage exhibits a rapid decrease in an outer part of the eye and the inner eyewall, and a slow decrease near the storm center. Examination on an absolute angular momentum coordinate indicates that the rapidly slow-down rotation in the outer edge of the eye and inner eyewall is faster than a slow-down rotation explained by surface friction. It suggests that asymmetric eddies transport angular momentum across the moat in the inner eyewall dissipation. This study is the first examination of dynamical contributions of asymmetric eddies to the inner-eyewall dissipation based on satellite-estimated tangential winds. Plain Language Summary Intense tropical cyclones often have the concentric secondary eyewall outside the original (primary) eyewall enclosing the eye (i.e., concentric eyewalls; CEs). The primary eyewall tends to decay after the secondary eyewall formation (i.e., eyewall replacement cycle; ERC). Dynamics of rapid changes of intensity and structure in an ERC remain an open question. To clarify the dynamics of the inner eyewall decaying, a quantitative

Multiple spacecraft formation forms a distributed space system where multiple spacecraft cooperatively exhibit the functionality of a single monolithic spacecraft or work in a cooperative way towards the completion of a common goal. This possibility of distributing the workload between different spacecraft provides the ability to work in parallel, enable economic and simple solutions in terms of spacecraft design, while is redundant towards partial or complete failure of a spacecraft. Some of the challenges, associated to the guidance and control aspects of the spacecraft formation, are to maintain a safe separation distance between each spacecraft in the formation to avoid any collision, the distribution of workload between the spacecraft group, and designing fuel efficient trajectories for each spacecraft. This thesis focuses on studying these challenges through two respective mission scenarios, a) the co-location of geostationary satellites, and b) the cooperative visual coverage of an asteroid. The first part of the thesis covers the development of guidance and control strategies to co-locate multiple geostationary satellites safely with a single operational slot. This part of the research is motivated by the growing demand to access the limited Earth resource of geostationary region; the growing use of low-thrust electric propulsion systems for geostationary satellite platforms; and the use of the same propulsion system for station keeping and momentum management of the reaction wheels to maintain a nadir pointing attitude for the satellites. Thus, to address the concurrent maneuver planning problem, a convex-optimization-based algorithm is proposed that incorporates a dual-rate prediction model to address the time scaling difference between the coupled slow orbital and fast attitude dynamics. The use of a combined prediction model in the optimization problem facilitates to include state constraints accounting for the desired orbital and momentum unloading requ

We introduce a computational framework to forecast cloud index (CI)fields for up to one hour on a spatial domain that covers a city. Such intra-hour CI forecasts are important to produce solar power forecasts of utility scale solar power and distributed rooftop solar. Our method combines a 2D advection model with cloud motion vectors (CMVs)derived from a mesoscale numerical weather prediction (NWP)model and sparse optical flow acting on successive, geostationary satellite images. We use ensemble data assimilation to combine these sources of cloud motion information based on the uncertainty of each data source. Our technique produces forecasts that have similar or lower root mean square error than reference techniques that use only optical flow, NWP CMV fields, or persistence. We describe how the method operates on three representative case studies and present results from 39 cloudy days.

We introduce a computational framework to forecast cloud index (CI)fields for up to one hour on a spatial domain that covers a city. Such intra-hour CI forecasts are important to produce solar power forecasts of utility scale solar power and distributed rooftop solar. Our method combines a 2D advection model with cloud motion vectors (CMVs)derived from a mesoscale numerical weather prediction (NWP)model and sparse optical flow acting on successive, geostationary satellite images. We use ensemble data assimilation to combine these sources of cloud motion information based on the uncertainty of each data source. Our technique produces forecasts that have similar or lower root mean square error than reference techniques that use only optical flow, NWP CMV fields, or persistence. We describe how the method operates on three representative case studies and present results from 39 cloudy days.

Accurate forecasting of Global Horizontal Irradiance (GHI) is essential for the integration of the solar resource in an electrical grid. We present a novel data-driven method aimed at delivering up to 6 h hourly probabilistic forecasts of GHI on top of a localized solar energy source. The method does not require calibration to adapt to regional differences in cloud dynamics, and uses only one type of data, covering Europe and Africa. It is thus suited for applications that require a GHI forecast for solar energy sources at different locations with few ground measurements. Cloud dynamics are emulated using an analog method based on 5 years of hourly images of geostationary satellite-derived irradiance, without using any numerical prediction model. This database contains both the images to be compared to the current atmospheric observation and their successors at one or more hours of interval. The physics of the system is emulated statistically, and no numerical prediction model is used. The method is tested on one year of data and five locations in Europe with different climatic conditions. It is compared to persistence (keeping the last observation frozen), ensemble persistence (generating a probabilistic forecast using the last observations) and an adaptive first order vector autoregressive model. As an application, the model is downscaled using ground measurements. In both cases, the analog method outperforms the classical statistical approaches. Results demonstrate the skill of the method in emulating cloud dynamics, and its potential to be coupled with a forecasting algorithm using ground measurements for operational applications.

Network of passive correlation ranging contains of five stations located in Ukraine and Latvia. It has been created at the initiative of the RI “Mykolaiv Astronomical Observatory” to have independent means to track the future Ukrainian geostationary satellite “Lybid”. Regular observations of the geostationary telecommunication satellite “Eutelsat-13B” has being carried out by the network since February 2015. A catalog of daily orbital elements of the tracked satellite has been created using the network observations. The analytical model SGP4/SDP4 of satellite motion and a numerical model of integration of equations of satellite motion are used to determine the orbital elements. The numerical model takes into account the gravitational attraction of the Sun and Moon, and non-spherical Earth. Software of the orbital elements determinations has been developed by the RI “Astronomical Observatory” of the Mechnikov Odesa National University.Satellite positions calculated using orbital elements from the catalog were compared with ones obtained using the NORAD space-track.org site and optical observations performed by the Ukrainian Network of Optical Stations. The satellite position comparisons were carried out only for time intervals of unperturbed motion of the satellite. The free motion time intervals were determined using the algorithm that had been tested using satellite owner data about the moments of satellite maneuvers. Herewith values of right ascension and declination were compared. Regular (mean) and random (standard deviation) values of the residuals are given in the report.

Accurate forecasting of Global Horizontal Irradiance (GHI) is essential for the integration of the solar resource in an electrical grid. We present a novel data-driven method aimed at delivering up to 6 h hourly probabilistic forecasts of GHI on top of a localized solar energy source. The method does not require calibration to adapt to regional differences in cloud dynamics, and uses only one type of data, covering Europe and Africa. It is thus suited for applications that require a GHI forecast for solar energy sources at different locations with few ground measurements. Cloud dynamics are emulated using an analog method based on 5 years of hourly images of geostationary satellite-derived irradiance, without using any numerical prediction model. This database contains both the images to be compared to the current atmospheric observation and their successors at one or more hours of interval. The physics of the system is emulated statistically, and no numerical prediction model is used. The method is tested on one year of data and five locations in Europe with different climatic conditions. It is compared to persistence (keeping the last observation frozen), ensemble persistence (generating a probabilistic forecast using the last observations) and an adaptive first order vector autoregressive model. As an application, the model is downscaled using ground measurements. In both cases, the analog method outperforms the classical statistical approaches. Results demonstrate the skill of the method in emulating cloud dynamics, and its potential to be coupled with a forecasting algorithm using ground measurements for operational applications.

Accurate forecasting of Global Horizontal Irradiance (GHI) is essential for the integration of the solar resource in an electrical grid. We present a novel data-driven method aimed at delivering up to 6 h hourly probabilistic forecasts of GHI on top of a localized solar energy source. The method does not require calibration to adapt to regional differences in cloud dynamics, and uses only one type of data, covering Europe and Africa. It is thus suited for applications that require a GHI forecast for solar energy sources at different locations with few ground measurements. Cloud dynamics are emulated using an analog method based on 5 years of hourly images of geostationary satellite-derived irradiance, without using any numerical prediction model. This database contains both the images to be compared to the current atmospheric observation and their successors at one or more hours of interval. The physics of the system is emulated statistically, and no numerical prediction model is used. The method is tested on one year of data and five locations in Europe with different climatic conditions. It is compared to persistence (keeping the last observation frozen), ensemble persistence (generating a probabilistic forecast using the last observations) and an adaptive first order vector autoregressive model. As an application, the model is downscaled using ground measurements. In both cases, the analog method outperforms the classical statistical approaches. Results demonstrate the skill of the method in emulating cloud dynamics, and its potential to be coupled with a forecasting algorithm using ground measurements for operational applications.

It is possible to identify certain characteristics of geostationary satellites by studying their photometry. This paper reviews some of the technical problems and methodologies concerning photometry of satellites, as well as their identification by photometric characteristics. The existing methods of identifying geostationary satellites using photometry are also summarized. The present Database of photometric and dynamic characteristics of the GSS, additional information, simplifying the input of the inverse problem  all this allows modern methods to identify unknown GSS with a probability up to 80%.

The purpose of this research is to investigate the influence of coverglass on arcing phenomena on GEO satellite solar array. Experiments were performed by using a large solar array coupon (400 x 400 mm). The Coupon has 50 Si cells. We measured surface potential on the solar array coupon immediately after arc inception. Extent of neutralization differed for each arc. Less charge was neutralized as the distance from arc position increases. At the worst case, 53 percent charge was neutralized at 325 mm in this experiment. Arc plasma propagation velocity was of the order of 10(exp 4) m/s but differed widely for each arc., JAXA Special Publication, 宇宙航空研究開発機構特別資料

This study reports on advanced GPS (Global Positioning System) navigation technologies with the objectives of reducing the operational time and effort through simplified attitude determination subsystems and orbit determination without the ground ranging. GPS attitude determination made use of the measurement of the carrier phase differences between multiple antennas. The biggest problem is the method of resolving the uncertainty in the wavelength integer multiple or the ambiguity. From a literature survey, the motion-based ambiguity estimation method was selected as the basis for the design of the GPS attitude determination method. The selected method estimated the attitude of a spacecraft and ambiguity simultaneously by making use of the changes in the baseline vector of the GPS antenna and in the directional vector of the GPS satellite. A covariance analysis program was developed in order to examine the validity of the designed system. The results of the analysis verified that the filter converged satisfactorily in the current attitude determination model. Next, the positioning of a Geostationary (GEO) satellite by using GPS signals was studied. When using GPS, the position of a spacecraft was determined by receiving four GPS signals. However, it was essentially impossible for a GEO satellite to receive four GPS signals since the signals originated at the other side of the earth. In order to make up for the shortage of the received GPS signals, an atomic clock was equipped with the receiver to stabilize time. An earth gravitational potential with fourth order was modeled in order to achieve orbit determination with higher accuracy. A covariance analysis was carried out in order to test the validity of the designed determination system. Results of the analysis confirmed that an extremely high-accuracy positioning could be achieved by using atomic clocks., 本研究は高精度GPS(全地球測位システム)航法技術について報告した。研究の目的は単純化した姿勢決定サブシステムと地上観測不要の軌道決定によって操作時間を短縮し、労力を軽減することである。GPSによる姿勢決定においては多層アンテナ間の搬送波の位相差の測定を利用する。この際の最大の問題は波長整数倍計測における不確実性、即ち曖昧性である。文献調査に基づいて、運動基準の曖昧性推定法をGPS姿勢決定法の設計の基準として選択した。この方法においては、GPSアンテナの基線ベクトルおよびGPS衛星の指向ベクトルの変化を利用して、宇宙船の姿勢と曖昧性を同時に推定する。設計したシステムの妥当性を検討するため共変性解析プログラムを開発した。解析の結果、現時点での姿勢決定モデルにおいてはフィルタの収斂性は満足すべきものであった。つぎにGPS信号による静止(GEO)衛星の測位を検討した。GPSを用いる場合、宇宙船の位置は4個のGPS信号を用いて決定される。しかしながら、GEO衛星にとって地球の反対側から発振されるGPSの4個の信号を受信することは本質的に不可能である。このGPS信号の不足を補うため、受信機に原子時計を組み込んで時間計測を安定化させた。高精度の軌道決定を達成するために4次元の地磁気ポテンシャルをモデルに用いた。設計した測位システムについて共変性解析を行なった。この結果、原子時計を用いることによって極めて高精度の測位を達成出来ることを確認した。

The total duration is evaluated in the condition that the Electrostatic Discharge (ESD) could occur and the number of expected trigger arcs for the secondary (sustained) arcs on solar array for the geostationary satellites, the Wideband InterNetworking engineering test and Demonstration Satellite (WINDS) and the Engineering Test Satellite 8 (ETS-8). For the evaluation, NASA Charging Analyzer Program (NASCAP) is used with the statistical plasma parameters observed by the Los Alamos National Laboratory geosynchronous satellites., 宇宙航空研究開発機構(JAXA)が開発中の静止軌道人工衛星のWINDS(超高速インターネット衛星)とETS-8(技術試験衛星8号機)について、NASA Charging Analyzer Program(NASCAP)を用いて表面帯電解析をおこなった。衛星表面帯電の影響として、衛星構造体(衛星アース)と誘電体、特に太陽電池表面のカバーガラスとの間の電位差により起こる放電(Electrostatic Discharge: ESD)の可能性がある帯電時間と、日照時での放電をトリガーとする持続放電による太陽電池の劣化とを見積もった。静止軌道の宇宙プラズマ環境パラメータとして、Los Alamos National Laboratory(LANL)の3つの静止衛星の延べ約12年間分のデータの統計解析結果を用いた。その結果、衛星により帯電特性が異なることが明らかになった。, JAXA Special Publication, 宇宙航空研究開発機構特別資料

Mission analysis and system study on Experimental Global imager for Geostationary orbit (EGG) were carried out to find out the specifications for a developable imager by clarifying its feasibility and technical issues. Evaluation of the performance characteristics of a two-dimensional intermediate infrared/thermal infrared detector utilizing existing consumer components was carried out to verify the materialization of EGG system. Parameters such as measurement band were set based on those used in the research on EGG/IR (Infrared) model in the preceding fiscal year. The size of detector used for the evaluation equipment was set to be more than 100 x 100 pixels, and the wavelength band of a spectral filter of spectrometer was to be corresponding to the respective band of EGG/IR. Dark time output property, input level and spectral characteristics, and detector readout property were evaluated. A two-dimensional bolometer type detector was used for the intermediate infrared/thermal infrared detector. Due to restriction on setting-up of incident light for a commercial detector, the sensitivity for 3 - 8 micrometer was inferior though that for 10 - 12 micrometer bands was relatively good. Performance for Noise Equivalent Delta Temperature (NE Delta T) was evaluated. Reduction of noise component was needed to materialize NE Delta T of around 0.3 - 0.5 K. As to extension of detector pixels, due to the restriction that sensitivity was lowered with extension of pixels, it was found that materialization of approximately 250 x 250 pixels detector was to be the technical limit., 静止軌道用イメージャ(EGG)の実現性および技術課題を明らかにして開発可能なイメージャ仕様を見出すため、イメージャのミッション解析とシステム検討を行った。EGGシステムの成立性を検証するため既存の民生品を用いた中間赤外・熱赤外用2次元検出器の性能特性評価を行った。測定バンドなどのパラメータには前年度研究で用いたEGG/IRモデルをベースラインとした。評価装置に用いた検出器の大きさは100×100画素以上とし、分光器の分光フィルタの波長帯はEGG/IRの各観測バンド相当とした。暗時出力特性、入力レベルとスペクトル特性、検出器読出し特性を評価した。中間赤外・熱赤外用2次元検出器にはボロメータ型を用いた。民生用検出器の入射光に対する設定上の制約のため、10〜12μm帯の感度は比較的良好であったが、3〜8μm帯の感度は低かった。雑音等価温度差(NEΔT)性能を評価した。0.3〜0.5K程度のNEΔTを実現するには雑音成分の低減が必要である。検出器の大画素化については、大画素化に伴う感度の低下という制約のため、250×250画素程度が技術的限界であることが分かった。

Individual studies of advanced Optical Inter-orbit Communication Engineering Test Systems (OICETS) were conducted in 1997. This year's work was organized as follows: (1) setting-up of the development goals; (2) identification of the technological elements to be developed; (3) examination of the technological elements to be developed and definition of the study themes and priorities; and (4) preparation of an abbreviated research and development schedule. Based on the results of the examinations in 1996 and 1997, a detailed investigation of the major technical problems associated with the development of advanced OICETS optical inter-orbit communication apparatuses was stated. Eventually, small and light-weight optical inter-orbit communication apparatuses with the weight of 30 kg, the power of 70 W and the transfer rate of 300 Mbps were expected to become available for practical use, once the studies of the advanced apparatuses of this type would be completed as scheduled., 先端的光衛星間通信技術試験システム(OICETS)の個別研究を1997年に行った。今年の研究を次のように組織した。すなわち、(1)開発目標の設定、(2)技術的な開発要素の明確化、(3)技術的な開発要素と研究テーマと優先順位の検討、および(4)短縮した研究と開発スケジュールの作成。1996年と1997年の試験結果に基づいて、先進的なOICETS光衛星間通信装置の開発に関連した主な技術的問題を詳細に計画した。最終的に、この形式の先進的装置に関する研究が計画通りに完了することにより、重量30kg、出力70W、および転送速度300Mbpsの小型で軽量の光衛星間通信装置を実用化することを計画した。

The experimental lunar lander is expected to be launched by H-2 rocket together with the geostationary satellite, DRTS (Data Relay Tracking Satellite), in summer of 2000 or in winter of 2001. In this report, two kinds of experimental lunar lander have been studied. One is a experimental landing system to learn the technology of soft landing on the lunar surface, and the other is a landing/relative VLBI (Very Long Baseline Interferometry) experiment system to investigate the capability of accurate position determination in addition to a technology of soft landing. At the start of the study, following dimensions have been settled as target values: 1,400 mm in height, 2,800 mm in width and 744 kg in max weight. This concept study has covered: (1) system concept study; (2) system analysis; (3) subsystem study; and (4) study of interface with H-2 rocket. In the system concept study, the conceptual design, system characteristic data and mission profile have been investigated. In the system analysis, weight distribution, flight trajectory, radiation exposure dose, requirements for propulsion system, communication capability, required electric energy and thermal environment have been investigated. The subsystem study have been performed regarding the structure, thermal control system, propulsion system, guidance/control system, obstacle avoidance system, communication/data processing system and electric power system. It was concluded that the weight reduction of about 100 kg should be required for the experimental landing/relative VLBI system, though the feasibility of the experimental landing system is promising., 本実験機は、H-2ロケットにより、静止衛星DRTS(データ中継追跡衛星)と相乗りで打ち上げられることを想定した。静止衛星DRTSは2000年夏期または2001年冬期に打ち上げられる予定である。実験機としては、月面への軟着陸技術の修得を目的とした着陸実験システムと、それに高精度位置決定機能を付加した着陸・相対VLBI(超長基線干渉)実験システムとの、2種類を検討した。検討に当たっては、実験機の諸元を、高さ1400mm、幅2800mm、最大重量744kgと定めた。構想検討は、(1)システム構想検討、(2)システム解析、(3)サブシステム検討、(4)ロケットとのインタフェース検討の4分野について行った。システム構想検討では、構想図、システム諸元、ミッションプロフィルをまとめた。システム解析では、重量構成、飛行経路、放射線被曝量、推進系への要求性能、通信機能、所要電力量、熱環境の検討を行った。サブシステム検討では、構体系、熱制御系、推進系、誘導制御系、障害物回避系、通信・データ処理系、電力系について検討を進めた。検討の結果、着陸実験システムの実現の見通しは得られたが、着陸・相対VLBI実験システムに対しては、今後さらに100kg程度の重量軽減を行う必要があるとの結論が得られた。

The optical inter orbit communication system was studied. The technological problems which are required to be demonstrated were defined, from which the development scenarios were studied. The following subjects were investigated in 1996FY. (1) As a part of the investigation of the trends in the research and development both domestically and abroad, present state of the research in the United States, Japan, and Europe was reviewed. NADSA is currently developing optical communication equipment to be installed aboard the Optical Interorbit Communications Engineering Test Satellite (OICETS). (2) A conceptual scheme for a future communication infrastructure was shown. An outline of the system utilizing optical interorbit communication was illustrated, and the major specifications and the implementation of optical communication equipment were discussed. These may be applicable to communications between low earth orbiting satellites and geostationary satellites, between geostationary satellites, and between space stations. (3) The technological issues which would arise in the assumption that the system would be demonstrated and launched around 2002 were identified and listed. (4) A study on the development scenario was performed. The most important item in the space demonstration was found to be the realization of a system in which an optical communication link with small sized, light weight equipment is operational with a highly reliable communication link., 光衛星間通信システムを研究し、実証を必要とする技術的課題を抽出し、これらの結果を基に開発のシナリオを研究した。1996年度には、以下の主題を検討した。(1)国内外における研究開発動向の調査の一環として、米国、日本、欧州における研究の現状を紹介した。NASDAでは、光衛星間通信実験衛星(OICETS)に搭載する光通信機を開発中である。(2)将来の宇宙通信インフラストラクチャについての想像図を示した。光衛星間通信を利用したシステムの概念と光通信機器に対する主要諸元と実現形式を検討した。この光衛星通信は地球周回低軌道衛星と静止衛星間、静止衛星間、および宇宙ステーション周りなどの通信に適用可能である。(3)2002年に打上予定のシステムを想定した、実証を要求される技術課題をリストアップした。(4)開発シナリオの検討を行った。この中で、宇宙通信に最も重要な項目は小型軽量機器での光通信回線が高回線信頼性で運用可能なことを実証することであると結論した。

Observation techniques for surface energy balancecomponents on kilometer scale. Several methods have been proposed to estimate ET overlarge areas which combine Earth Observation Satellite datawith standard climate data. Here we use the Makkinkapproach where incoming solar radiation is obtained bycalculating exoatmospheric incoming solar radiation, usingvisible data from GOES West to estimate cloudiness and16-day composite MODIS Enhanced Vegetation Index data toestimate fractional vegetation cover. This methodology can beused operationally at a spatial resolution of 1 km2 butvalidation data are required at a similar spatial scale. LargeAperture Scintillometers transmit and receive near infraredradiation over distances of several kilometers and providemeasurements of the structure parameter for the refractiveindex of air which is related by Monin-Obukhov SimilarityTheory to the surface sensible heat flux (H), which requiresmeasurements of air temperature, pressure and wind speed.ET can then be obtained indirectly as the residual of theenergy balance, ET = Rn – G – H so that we need estimates ofNet Radiation (Rn) and Soil Heat Flux (G) as well. Ascintillometer (Scintec BLS-450) was installed over anirrigated vineyard with area of 72 hectares (1200m x 600m) inJune 6th 2009. Net Radiation was measured in the field andsoil heat flux was estimated using G = A * Rn, where theparameter A was obtained from 8-day composite MODIS LandSurface Temperature data. Comparison of ET derived fromsatellite and scintillometer for June 2009 showed considerablescatter with r2 = 0.81 and ETSAT = 1.12 * ETBLS. Thisapparent overestimation from the satellite-based ET is similarto that found in previous work. However, in these initialcalculations it was assumed that unstable conditions wouldprevail during the daytime but it appears that stableconditions often occur in the late afternoon. Secondly, theestimation of G needs to be carefully revised since this canhave a large effect on ET. These fa

Providing affordable Internet access to rural populations in large developing countries to aid economic and social progress, using various non-conventional techniques has been a topic of active research recently. The main obstacle in providing fiber-optic based terrestrial Internet links to remote villages is the cost involved in laying the cable network and disproportionately low rate of return on investment due to low density of paid users. The conventional alternative to this is providing Internet access using geostationary satellite links, which can prove commercially infeasible in predominantly cost-driven rural markets in developing economies like India or China due to high access cost per user. A low-cost derivative of the conventional satellite-based Internet access system can be developed by utilizing an aging geostationary satellite nearing the end of its active life, allowing it to enter an inclined geosynchronous orbit by limiting station keeping to only east-west maneuvers to save fuel. Eliminating the need for individual satellite receiver modules by using one centrally located earth station per village and providing last mile connectivity using Wi-Fi can further reduce the access cost per user. A Ku band system design for rural India based on this concept, using an Intelsat 906 satellite is proposed in this thesis. The path of the satellite and the tracking requirements at village stations are determined. Components required for various blocks of the system are defined. Modulation schemes, FEC, data rates, number of customers to be served, link availability and outage statistics are presented. Quantitative analysis using link budgets and ITU rain models are provided. An optimized system design and a commercial deployment model are suggested which show the system is economically feasible.

Providing affordable Internet access to rural populations in large developing countries to aid economic and social progress, using various non-conventional techniques has been a topic of active research recently. The main obstacle in providing fiber-optic based terrestrial Internet links to remote villages is the cost involved in laying the cable network and disproportionately low rate of return on investment due to low density of paid users. The conventional alternative to this is providing Internet access using geostationary satellite links, which can prove commercially infeasible in predominantly cost-driven rural markets in developing economies like India or China due to high access cost per user. A low-cost derivative of the conventional satellite-based Internet access system can be developed by utilizing an aging geostationary satellite nearing the end of its active life, allowing it to enter an inclined geosynchronous orbit by limiting station keeping to only east-west maneuvers to save fuel. Eliminating the need for individual satellite receiver modules by using one centrally located earth station per village and providing last mile connectivity using Wi-Fi can further reduce the access cost per user. A Ku band system design for rural India based on this concept, using an Intelsat 906 satellite is proposed in this thesis. The path of the satellite and the tracking requirements at village stations are determined. Components required for various blocks of the system are defined. Modulation schemes, FEC, data rates, number of customers to be served, link availability and outage statistics are presented. Quantitative analysis using link budgets and ITU rain models are provided. An optimized system design and a commercial deployment model are suggested which show the system is economically feasible.

中国の気象衛星FY2B赤外画像のジオコーディング処理を行った。処理に必要な幾何学的情報などが不十分であるため，古典的な手法を用いた幾何補正を行いGOES-9のデータとの比較を行うことで，データの精度や信頼性についての議論を行った。処理されたFY2Bのデータは大陸スケールの対流活動の解析データとして十分使え，精度の高い幾何補正処理が要求されるメソスケールの対流活動の解析データとしても利用できることがわかった。, FY2B infrared images received in Disaster Prevention Research Institute, Kyoto University, have been geocoded by using classic method. Received FY2B raw images do not include some important parameters those are essential to the accurate geocoding, so that infrared brightness temperatures obtained from processed FY2B data are compared with those derived from GOES-9 image to measure the reliability. The results show the processed FY2B data is not only available for the synoptic scale analysis but also can be used for the meso-scale analysis of convective activity.

The Outline is as follows: Geosynchronous satellite failures; Geosynchronous Monitoring and Warning System; Preliminary results; Summary and future work., See Also ADM001334. Presented at the 2001 Space Control Conference (19th Annual) held in Lincoln Laboratory, Hanscom AFB, MA on 3-5 April 2001. --Original contains color plates: All DTIC reproductions will be in black and white. Contains viewgraphs only. This work was performed under a Cooperative Research and Development Agreement between MIT/LL and GE-Americom, SATMEX, and Telesat Canada.

This technical note provides descriptions and photograph examples of cloud/earth phenomena as seen from polar-orbiting and geostationary meteorological satellites(METSATS). It begins with a look at basic cloud types, covers comma cloud systems, low-and high-level wind flow cloud patterns and ends with miscellaneous cloud/earth phenomena. It is meant as a quick reference to help in METSAT imagery interpretation, and can serve as a portion of a unit's METSAT Imagery Reference File (MIRF)., See also Rept. no. 1WW-TN-83-001, AD-B080 673L.

V této práci jsou zpracovány základní zákony a poznatky týkající se vesmírných letů na oběžnou dráhu okolo Země a také je zde vypracován návod pro začínající uživatele, kteří chtějí pracovat s programem GMAT (General Mission Analysis Tool), což je program sloužící k navrhování vesmírných misí. V závěrečné části práce je též použití programu předvedeno na konkrétním příkladu mise družice (CubeSat) na geostacionární oběžnou dráhu. V této části je popsán postup práce, jednotlivé podstatné funkce programu a možnosti a způsob práce v něm. Na závěr jsou vyhodnoceny grafické a datové výstupy ze simulace. Výstupem práce je tedy komplexní charakteristika základů problému návrhu vesmírných misí a stručný návod pro práci se softwarem GMAT, který lze v budoucnu využít ve výuce., In this work, there are basic laws and knowledge relating to space flights into an orbit around the Earth. Also, there are instructions for beginners, who want to work with the GMAT program (General Mission Analysis Tool), which is the program used for designing space missions. In the final part of the work, there is also a use of the program demonstrated on a specific mission of a satellite (CubeSat) into the Geostationary Earth Orbit. In this section, there is a described method of work, individual relevant functions of the program and possibilities, and a way of work in it. Finally, graphical and data outputs of the simulation are evaluated. Therefore, the output of the work is complex characteristics of the basics of problems of space mission design and a brief GMAT software guide, which could be used in the future to teach.

V této práci jsou zpracovány základní zákony a poznatky týkající se vesmírných letů na oběžnou dráhu okolo Země a také je zde vypracován návod pro začínající uživatele, kteří chtějí pracovat s programem GMAT (General Mission Analysis Tool), což je program sloužící k navrhování vesmírných misí. V závěrečné části práce je též použití programu předvedeno na konkrétním příkladu mise družice (CubeSat) na geostacionární oběžnou dráhu. V této části je popsán postup práce, jednotlivé podstatné funkce programu a možnosti a způsob práce v něm. Na závěr jsou vyhodnoceny grafické a datové výstupy ze simulace. Výstupem práce je tedy komplexní charakteristika základů problému návrhu vesmírných misí a stručný návod pro práci se softwarem GMAT, který lze v budoucnu využít ve výuce., In this work, there are basic laws and knowledge relating to space flights into an orbit around the Earth. Also, there are instructions for beginners, who want to work with the GMAT program (General Mission Analysis Tool), which is the program used for designing space missions. In the final part of the work, there is also a use of the program demonstrated on a specific mission of a satellite (CubeSat) into the Geostationary Earth Orbit. In this section, there is a described method of work, individual relevant functions of the program and possibilities, and a way of work in it. Finally, graphical and data outputs of the simulation are evaluated. Therefore, the output of the work is complex characteristics of the basics of problems of space mission design and a brief GMAT software guide, which could be used in the future to teach.

V této práci jsou zpracovány základní zákony a poznatky týkající se vesmírných letů na oběžnou dráhu okolo Země a také je zde vypracován návod pro začínající uživatele, kteří chtějí pracovat s programem GMAT (General Mission Analysis Tool), což je program sloužící k navrhování vesmírných misí. V závěrečné části práce je též použití programu předvedeno na konkrétním příkladu mise družice (CubeSat) na geostacionární oběžnou dráhu. V této části je popsán postup práce, jednotlivé podstatné funkce programu a možnosti a způsob práce v něm. Na závěr jsou vyhodnoceny grafické a datové výstupy ze simulace. Výstupem práce je tedy komplexní charakteristika základů problému návrhu vesmírných misí a stručný návod pro práci se softwarem GMAT, který lze v budoucnu využít ve výuce., In this work, there are basic laws and knowledge relating to space flights into an orbit around the Earth. Also, there are instructions for beginners, who want to work with the GMAT program (General Mission Analysis Tool), which is the program used for designing space missions. In the final part of the work, there is also a use of the program demonstrated on a specific mission of a satellite (CubeSat) into the Geostationary Earth Orbit. In this section, there is a described method of work, individual relevant functions of the program and possibilities, and a way of work in it. Finally, graphical and data outputs of the simulation are evaluated. Therefore, the output of the work is complex characteristics of the basics of problems of space mission design and a brief GMAT software guide, which could be used in the future to teach.

V této práci jsou zpracovány základní zákony a poznatky týkající se vesmírných letů na oběžnou dráhu okolo Země a také je zde vypracován návod pro začínající uživatele, kteří chtějí pracovat s programem GMAT (General Mission Analysis Tool), což je program sloužící k navrhování vesmírných misí. V závěrečné části práce je též použití programu předvedeno na konkrétním příkladu mise družice (CubeSat) na geostacionární oběžnou dráhu. V této části je popsán postup práce, jednotlivé podstatné funkce programu a možnosti a způsob práce v něm. Na závěr jsou vyhodnoceny grafické a datové výstupy ze simulace. Výstupem práce je tedy komplexní charakteristika základů problému návrhu vesmírných misí a stručný návod pro práci se softwarem GMAT, který lze v budoucnu využít ve výuce., In this work, there are basic laws and knowledge relating to space flights into an orbit around the Earth. Also, there are instructions for beginners, who want to work with the GMAT program (General Mission Analysis Tool), which is the program used for designing space missions. In the final part of the work, there is also a use of the program demonstrated on a specific mission of a satellite (CubeSat) into the Geostationary Earth Orbit. In this section, there is a described method of work, individual relevant functions of the program and possibilities, and a way of work in it. Finally, graphical and data outputs of the simulation are evaluated. Therefore, the output of the work is complex characteristics of the basics of problems of space mission design and a brief GMAT software guide, which could be used in the future to teach.