The Experts below are selected from a list of 7983 Experts worldwide ranked by ideXlab platform
Warren E. Dixon - One of the best experts on this subject based on the ideXlab platform.
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Distributed Connectivity Preserving Target Tracking With Random Sensing
IEEE Transactions on Automatic Control, 2019Co-Authors: Emily A. Doucette, Warren E. DixonAbstract:A networked multiagent system is tasked to cooperatively track a mobile target, where agents experience random loss of sensing due to occlusions resulting from the target moving in a complex environment. A directed random graph is used to model the time-varying availability of the target states to agents, where the connection of the directed edge in the graph is assumed to be probabilistic and evolves according to a two-state Markov Model. An almost sure consensus algorithm is developed for all agents to achieve consensus on the target position. Due to limited communication capabilities (i.e., the agents can only communicate within a certain range), agent motion may result in a disconnected communication network, leading to the failure of consensus to the target states. Motivated to preserve the graph connectivity of the position-dependent communication network, an algebraic-connectivity-based distributed motion controller is developed to ensure that the communication network remains connected during cooperative target tracking. Compared to existing results, our approach allows agents to break existing links when necessary as long as the algebraic connectivity remains positive, which provides more motion freedom for agents in Mission Operation. Moreover, our approach only requires information exchange within two-hop neighbors to preserve the network connectivity, which eliminates the need of iterative estimation of the algebraic connectivity.
Emily A. Doucette - One of the best experts on this subject based on the ideXlab platform.
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Distributed Connectivity Preserving Target Tracking With Random Sensing
IEEE Transactions on Automatic Control, 2019Co-Authors: Emily A. Doucette, Warren E. DixonAbstract:A networked multiagent system is tasked to cooperatively track a mobile target, where agents experience random loss of sensing due to occlusions resulting from the target moving in a complex environment. A directed random graph is used to model the time-varying availability of the target states to agents, where the connection of the directed edge in the graph is assumed to be probabilistic and evolves according to a two-state Markov Model. An almost sure consensus algorithm is developed for all agents to achieve consensus on the target position. Due to limited communication capabilities (i.e., the agents can only communicate within a certain range), agent motion may result in a disconnected communication network, leading to the failure of consensus to the target states. Motivated to preserve the graph connectivity of the position-dependent communication network, an algebraic-connectivity-based distributed motion controller is developed to ensure that the communication network remains connected during cooperative target tracking. Compared to existing results, our approach allows agents to break existing links when necessary as long as the algebraic connectivity remains positive, which provides more motion freedom for agents in Mission Operation. Moreover, our approach only requires information exchange within two-hop neighbors to preserve the network connectivity, which eliminates the need of iterative estimation of the algebraic connectivity.
V K Jordanova - One of the best experts on this subject based on the ideXlab platform.
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the occurrence and wave properties of h he and o band emic waves observed by the van allen probes
Journal of Geophysical Research, 2015Co-Authors: A A Saikin, J C Zhang, R C Allen, C W Smith, L M Kistler, Harlan E Spence, R B Torbert, C A Kletzing, V K JordanovaAbstract:We perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes Mission to investigate the spatial distribution of their occurrence, wave power, ellipticity, and normal angle. The Van Allen Probes have been used which allow us to explore the inner magnetosphere (1.1 to 5.8 RE). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes are used to identify EMIC wave events for the first 22 months of the Mission Operation (8 September 2012 to 30 June 2014). EMIC waves are examined in H+, He+, and O+ bands. Over 700 EMIC wave events have been identified over the three different wave bands (265 H+-band events, 438 He+-band events, and 68 O+-band events). EMIC wave events are observed between L = 2–8, with over 140 EMIC wave events observed below L = 4. Results show that H+-band EMIC waves have two peak magnetic local time (MLT) occurrence regions: prenoon (09:00 0.1 nT2/Hz), especially in the afternoon sector. Ellipticity observations reveal that linearly polarized EMIC waves dominate in lower L shells.
R C Allen - One of the best experts on this subject based on the ideXlab platform.
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the occurrence and wave properties of h he and o band emic waves observed by the van allen probes
Journal of Geophysical Research, 2015Co-Authors: A A Saikin, J C Zhang, R C Allen, C W Smith, L M Kistler, Harlan E Spence, R B Torbert, C A Kletzing, V K JordanovaAbstract:We perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes Mission to investigate the spatial distribution of their occurrence, wave power, ellipticity, and normal angle. The Van Allen Probes have been used which allow us to explore the inner magnetosphere (1.1 to 5.8 RE). Magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science on board the Van Allen Probes are used to identify EMIC wave events for the first 22 months of the Mission Operation (8 September 2012 to 30 June 2014). EMIC waves are examined in H+, He+, and O+ bands. Over 700 EMIC wave events have been identified over the three different wave bands (265 H+-band events, 438 He+-band events, and 68 O+-band events). EMIC wave events are observed between L = 2–8, with over 140 EMIC wave events observed below L = 4. Results show that H+-band EMIC waves have two peak magnetic local time (MLT) occurrence regions: prenoon (09:00 0.1 nT2/Hz), especially in the afternoon sector. Ellipticity observations reveal that linearly polarized EMIC waves dominate in lower L shells.
David J. Korsmeyer - One of the best experts on this subject based on the ideXlab platform.
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Intelligent Systems Technologies for Human Space Exploration Mission Operations
2011 IEEE Fourth International Conference on Space Mission Challenges for Information Technology, 2011Co-Authors: Ernest E. Smith, David J. KorsmeyerAbstract:Human space flight and exploration continues to be a key goal of the NASA, with an emphasis on utilizing new technologies to improve the effectiveness, efficiencies and safety associated with this endeavor, including the ground-based Mission support. This search for improvement has led to cross-fertilization between the advanced software development community and the manned spaceflight Operations community within NASA. This paper discusses the latest status of the on-going application of a variety of intelligent systems technologies adopted for manned Mission Operations. We discuss several specific projects between the Ames Research Center Intelligent Systems Division and the Johnson Space Center's Mission Operations Directorate, and how these technologies and projects are enhancing the Mission Operations support for the International Space Station and preparing for the Mission Operation support of the future human exploration Programs.
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Utilization of Intelligent Systems Technologies for Manned Mission Operations Support
SpaceOps 2010 Conference, 2010Co-Authors: David J. Korsmeyer, Ernest E. SmithAbstract:With the International Space Station being extended to 2020, there is additional emphasis in the manned spaceflight program to find more efficient and effective ways of providing the ground-based Mission support. This search for improvement h as led to a cross-fertilization between the advanced software development community and the manned spaceflight Operations community. Many Mission Operations systems and tools have been developed over the past decades as NASA has operated the Mars robotic Missions, the Space Shuttle, and the International Space Station. NASA Ames Research Center has been developing and applying its advanced intelligent systems research to Mission Operations tools for both unmanned Mars Missions Operations since 2001 and to manned Operations with NASA Johnson Space Center since 2006. In particular, the fundamental advanced software development work, and the experience and capabilities developed for Mission Operations systems for the Mars Exploration Rovers, and Phoenix Lander have enhanced the development and application of advanced Mission Operation systems for the International Space Station and future spacecraft. This paper discusses the on-going application of a variety of intelligent systems technologies adopted for manned Mission Operations. We discuss several specific projects between the Ames Research Center and the Johnson Space Center’s Mission Operations Directorate, and how these technologies and projects are enhancing the Mission Operations support for the Internati onal Space Station and preparing for the Mission Operation support of the future human exploration programs. I. Introduction NASA is posturing itself for the next major step in the exploration of space, and will require the development of many new capabilities including the design of new spacecraft, new launch services, and new processes and tools associated with the Mission Operations support. The Mission Operations support includes the planning of the NASA Missions, the training of the crew and flight control team, and the Mission execution. While the specific targets for NASA Mission Operations beyond the ISS Program are currently being assessed, it is clear that NASA will need to infuse new technologies into the new space exploration initiatives. The range and complexity of these exploration Missions will require an unprecedented use of automation and robotics in support of human crews. This will require the Operations of manned spacecraft in close conjunction with planetary robotic systems. NASA‘s current space flight Missions are largely segmented into unmanned Missions funded by the NASA‘s Science Mission Directorate, and the human spaceflight Missions operated by the Spaceflight Operations Mission
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Applications of Intelligent Systems for Advanced Mission Operations
SpaceOps 2008 Conference, 2008Co-Authors: David J. Korsmeyer, Ernest E. SmithAbstract:ASA’s Constellation Program (CxP) is the next major step in the exploration of space, and will require the development of many new capabilities including the design of new spacecraft and lunar surface infrastructure, new launch services, and new processes and tools associated with the Mission Operations support. The Mission Operations support includes the planning of the CxP Missions, the training of the crew and flight control team, and the Mission execution. CxP plans to develop a new spacecraft, the Orion Crew Exploration Vehicle (CEV), and a new launch infrastructure, Ares. NASA also plans for the return of humans to the Moon, and the eventual human exploration of Mars. The range and complexity of these exploration Missions will require an unprecedented use of automation and robotics in support of human crews. This will require the Operations of manned spacecraft in close conjunction with planetary robotic systems. NASA’s current space flight Missions are largely segmented into unmanned Missions funded by the NASA’s Science Mission Directorate, and the human spaceflight Missions operated by the Spaceflight Operations Mission Directorate. Typically the organizations within NASA that operate the unmanned Missions are different from the organizations that operated crewed space systems. The Mission Operations requirements and needs for the robotic Missions have been relatively distinct from those for the Space Shuttle and the International Space Station (ISS). Developing and validating the new exploration spacecraft and its associated infrastructure may place requirements on Operations design for near-term explorations (e.g. lunar) Missions. Separate Mission Operations processes—and cultures—have evolved to support manned Missions and unmanned/robotic Missions, each geared to the unique challenges of the two classes of Missions. 1 Thus, enabling the technologies and process innovations that benefited the robotic Missions to also benefit crewed Missions is not simple or straightforward. NASA Ames Research Center has been working with both human spaceflight and robotic systems communities now for several years developing Mission Operations tools and system, and is helping to bridge the gap between manned and robotic Mission Operation tools. The CxP Mission Operation Project Office is working with NASA Ames to create new intelligent systems for Mission Operations. 2 This paper updates the status report earlier in 2007 to the space Operations community.