The Experts below are selected from a list of 91596 Experts worldwide ranked by ideXlab platform
Sreeja Nag - One of the best experts on this subject based on the ideXlab platform.
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observing system simulations for Small Satellite formations estimating bidirectional reflectance
International Journal of Applied Earth Observation and Geoinformation, 2015Co-Authors: Sreeja Nag, Charles K Gatebe, Olivier De WeckAbstract:Abstract The bidirectional reflectance distribution function (BRDF) gives the reflectance of a target as a function of illumination geometry and viewing geometry, hence carries information about the anisotropy of the surface. BRDF is needed in remote sensing for the correction of view and illumination angle effects (for example in image standardization and mosaicing), for deriving albedo, for land cover classification, for cloud detection, for atmospheric correction, and other applications. However, current spaceborne instruments provide sparse angular sampling of BRDF and airborne instruments are limited in the spatial and temporal coverage. To fill the gaps in angular coverage within spatial, spectral and temporal requirements, we propose a new measurement technique: use of Small Satellites in formation flight, each Satellite with a VNIR (visible and near infrared) imaging spectrometer, to make multi-spectral, near-simultaneous measurements of every ground spot in the swath at multiple angles. This paper describes an observing system simulation experiment (OSSE) to evaluate the proposed concept and select the optimal formation architecture that minimizes BRDF uncertainties. The variables of the OSSE are identified; number of Satellites, measurement spread in the view zenith and relative azimuth with respect to solar plane, solar zenith angle, BRDF models and wavelength of reflection. Analyzing the sensitivity of BRDF estimation errors to the variables allow simplification of the OSSE, to enable its use to rapidly evaluate formation architectures. A 6-Satellite formation is shown to produce lower BRDF estimation errors, purely in terms of angular sampling as evaluated by the OSSE, than a single spacecraft with 9 forward-aft sensors. We demonstrate the ability to use OSSEs to design Small Satellite formations as complements to flagship mission data. The formations can fill angular sampling gaps and enable better BRDF products than currently possible.
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Cost and risk analysis of Small Satellite constellations for earth observation
Aerospace Conference 2014 IEEE, 2014Co-Authors: Sreeja Nag, Jacqueline LemoigneAbstract:Distributed Space Missions (DSMs) are gaining momentum in their application to Earth science missions owing to their ability to increase observation sampling in spatial, spectral, temporal and angular dimensions. Past literature from academia and industry have proposed and evaluated many cost models for spacecraft as well as methods for quantifying risk. However, there have been few comprehensive studies quantifying the cost for multiple spacecraft, for Small Satellites and the cost risk for the operations phase of the project which needs to be budgeted for when designing and building efficient architectures. This paper identifies the three critical problems with the applicability of current cost and risk models to distributed Small Satellite missions and uses data-based modeling to suggest changes that can be made in some of them to improve applicability. Learning curve parameters to make multiple copies of the same unit, technological complexity based costing and COTS enabled Small Satellite costing have been studied and insights provided.
Scott C. Burleigh - One of the best experts on this subject based on the ideXlab platform.
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survey of inter Satellite communication for Small Satellite systems physical layer to network layer view
arXiv: Networking and Internet Architecture, 2016Co-Authors: Radhika Radhakrishnan, William W. Edmonson, Fatemeh Afghah, Frank Pinto, Ramon Martinez Rodriguezosorio, Scott C. BurleighAbstract:Small Satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced Small Satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of Satellites provide improved spatial and temporal resolution of the target. Small Satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-Satellite communication is a key aspect when Satellites fly in formation. In this paper, we present the various researches being conducted in the Small Satellite community for implementing inter-Satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-Satellite communications for multiple Small Satellite missions. Specific topics include proposed solutions for some of the challenges faced by Small Satellite systems, enabling operations using a network of Small Satellites, and some examples of Small Satellite missions involving formation flying aspects.
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Survey of Inter-Satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View
IEEE Communications Surveys & Tutorials, 2016Co-Authors: Radhika Radhakrishnan, William W. Edmonson, Fatemeh Afghah, Ramon Martinez Rodriguez-osorio, Frank Pinto, Scott C. BurleighAbstract:Small Satellite systems enable a whole new class of missions for navigation, communications, remote sensing, and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass, and power constraints, mass-produced Small Satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. The proliferation of Small Satellites will enable a better understanding of the near-Earth environment and provide an efficient and economical means to access the space through the use of multi-Satellite solution. Constellation of Satellites provide improved spatial and temporal resolution of the target. Small Satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft, which opens the door to new applications. Future space missions are envisioned to become more complex and operate farther from Earth, and will need to support autonomous operations with minimal human intervention. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space-based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-Satellite communication is a key aspect when Satellites fly in formation. In this survey, we present the various research being conducted in the Small Satellite community for implementing inter-Satellite communications based on the open system interconnection (OSI) model. This survey also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link, and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-Satellite communications for multiple Small Satellite missions. Specific topics include proposed solutions for some of the challenges faced by Small Satellite systems, enabling operations using a network of Small Satellites, and some examples of Small Satellite missions involving formation flying aspects.
Di Zhou - One of the best experts on this subject based on the ideXlab platform.
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mission aware contact plan design in resource limited Small Satellite networks
IEEE Transactions on Communications, 2017Co-Authors: Di Zhou, Min Sheng, Xijun Wang, C Xu, Jiandong LiAbstract:Small Satellite networks (SSNs) are playing an increasing role in nowadays earth observation due to their less development cost and energy consumption. In SSNs, it is pivotal to transmit a huge amount of data for differentiated missions to ground stations. Nevertheless, due to limited transponders and energy budget, not all contacts, i.e., potential available communication links, are feasible in data delivery. Besides, Satellite downlink channel conditions are indeed time-varying due to atmospheric precipitation. Therefore, one daunting challenge is searching for feasible contacts termed as contact plan design with consideration of the differentiation for missions. In this paper, we exploit an extended time-evolving graph to characterize network resources. Based on the graph, we formulate the design of mission-aware contact plan, aiming at maximizing network profit in terms of sum weighted data volume as a mixed-integer linear programming. Due to its NP-hardness, we propose a primal decomposition method to efficiently solve the formulated problem by exploiting its special structure. To further reduce the complexity, we propose a link metric considering the issues of residual energy of Satellites, time-varying Satellite downlink contact capacity, and the differentiation for missions in the conflict graph. Based on the conflict graph, we devise a heuristic algorithm to design contact plan. Simulation results demonstrate the efficiency of the proposed algorithms and necessitate the consideration of the time-varying downlinks and the differentiation of missions for contact plan design.
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an analytical framework for resource limited Small Satellite networks
IEEE Communications Letters, 2016Co-Authors: Runzi Liu, Min Sheng, Kingshan Lui, Xijun Wang, Yu Wang, Di ZhouAbstract:In this letter, we propose an analytical framework for resource-limited Small Satellite networks. To handle the challenges raised by the intertwined impacts of energy budgets, Satellites' movements and delay requirements on data acquisition and delivery process, we extend the traditional time-expanded graph to model the data acquisition and energy managements. Based on this graph model, we formulate the data acquisition and delivery strategies into an optimization problem aiming at maximizing the delay-constrained throughput. Our framework allows us to investigate the impact of different factors on the network performance. Simulation results highlight the necessity of considering the constraints of energy budgets and delay requirements jointly in the design of data delivery strategies.
Radhika Radhakrishnan - One of the best experts on this subject based on the ideXlab platform.
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survey of inter Satellite communication for Small Satellite systems physical layer to network layer view
arXiv: Networking and Internet Architecture, 2016Co-Authors: Radhika Radhakrishnan, William W. Edmonson, Fatemeh Afghah, Frank Pinto, Ramon Martinez Rodriguezosorio, Scott C. BurleighAbstract:Small Satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced Small Satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of Satellites provide improved spatial and temporal resolution of the target. Small Satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-Satellite communication is a key aspect when Satellites fly in formation. In this paper, we present the various researches being conducted in the Small Satellite community for implementing inter-Satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-Satellite communications for multiple Small Satellite missions. Specific topics include proposed solutions for some of the challenges faced by Small Satellite systems, enabling operations using a network of Small Satellites, and some examples of Small Satellite missions involving formation flying aspects.
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Survey of Inter-Satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View
IEEE Communications Surveys & Tutorials, 2016Co-Authors: Radhika Radhakrishnan, William W. Edmonson, Fatemeh Afghah, Ramon Martinez Rodriguez-osorio, Frank Pinto, Scott C. BurleighAbstract:Small Satellite systems enable a whole new class of missions for navigation, communications, remote sensing, and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass, and power constraints, mass-produced Small Satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. The proliferation of Small Satellites will enable a better understanding of the near-Earth environment and provide an efficient and economical means to access the space through the use of multi-Satellite solution. Constellation of Satellites provide improved spatial and temporal resolution of the target. Small Satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft, which opens the door to new applications. Future space missions are envisioned to become more complex and operate farther from Earth, and will need to support autonomous operations with minimal human intervention. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space-based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-Satellite communication is a key aspect when Satellites fly in formation. In this survey, we present the various research being conducted in the Small Satellite community for implementing inter-Satellite communications based on the open system interconnection (OSI) model. This survey also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link, and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-Satellite communications for multiple Small Satellite missions. Specific topics include proposed solutions for some of the challenges faced by Small Satellite systems, enabling operations using a network of Small Satellites, and some examples of Small Satellite missions involving formation flying aspects.
Jiandong Li - One of the best experts on this subject based on the ideXlab platform.
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mission aware contact plan design in resource limited Small Satellite networks
IEEE Transactions on Communications, 2017Co-Authors: Di Zhou, Min Sheng, Xijun Wang, C Xu, Jiandong LiAbstract:Small Satellite networks (SSNs) are playing an increasing role in nowadays earth observation due to their less development cost and energy consumption. In SSNs, it is pivotal to transmit a huge amount of data for differentiated missions to ground stations. Nevertheless, due to limited transponders and energy budget, not all contacts, i.e., potential available communication links, are feasible in data delivery. Besides, Satellite downlink channel conditions are indeed time-varying due to atmospheric precipitation. Therefore, one daunting challenge is searching for feasible contacts termed as contact plan design with consideration of the differentiation for missions. In this paper, we exploit an extended time-evolving graph to characterize network resources. Based on the graph, we formulate the design of mission-aware contact plan, aiming at maximizing network profit in terms of sum weighted data volume as a mixed-integer linear programming. Due to its NP-hardness, we propose a primal decomposition method to efficiently solve the formulated problem by exploiting its special structure. To further reduce the complexity, we propose a link metric considering the issues of residual energy of Satellites, time-varying Satellite downlink contact capacity, and the differentiation for missions in the conflict graph. Based on the conflict graph, we devise a heuristic algorithm to design contact plan. Simulation results demonstrate the efficiency of the proposed algorithms and necessitate the consideration of the time-varying downlinks and the differentiation of missions for contact plan design.
