WorldWideScience

Sample records for satellite operations control

  1. SPOT satellite family: Past, present, and future of the operations in the mission and control center

    Science.gov (United States)

    Philippe, Pacholczyk

    1993-01-01

    SPOT sun-synchronous remote sensing satellites are operated by CNES since February 1986. Today, the SPOT mission and control center (CCM) operates SPOT1, SPOT2, and is ready to operate SPOT3. During these seven years, the way to operate changed and the CCM, initially designed for the control of one satellite, has been modified and upgraded to support these new operating modes. All these events have shown the performances and the limits of the system. A new generation of satellite (SPOT4) will continue the remote sensing mission during the second half of the 90's. Its design takes into account the experience of the first generation and supports several improvements. A new generation of control center (CMP) has been developed and improves the efficiency, quality, and reliability of the operations. The CMP is designed for operating two satellites at the same time during launching, in-orbit testing, and operating phases. It supports several automatic procedures and improves data retrieval and reporting.

  2. A university-based distributed satellite mission control network for operating professional space missions

    Science.gov (United States)

    Kitts, Christopher; Rasay, Mike

    2016-03-01

    For more than a decade, Santa Clara University's Robotic Systems Laboratory has operated a unique, distributed, internet-based command and control network for providing professional satellite mission control services for a variety of government and industry space missions. The system has been developed and is operated by students who become critical members of the mission teams throughout the development, test, and on-orbit phases of these missions. The mission control system also supports research in satellite control technology and hands-on student aerospace education. This system serves as a benchmark for its comprehensive nature, its student-centric nature, its ability to support NASA and industry space missions, and its longevity in providing a consistent level of professional services. This paper highlights the unique features of this program, reviews the network's design and the supported spacecraft missions, and describes the critical programmatic features of the program that support the control of professional space missions.

  3. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  4. Assessment for Operator Confidence in Automated Space Situational Awareness and Satellite Control Systems

    Science.gov (United States)

    Gorman, J.; Voshell, M.; Sliva, A.

    2016-09-01

    The United States is highly dependent on space resources to support military, government, commercial, and research activities. Satellites operate at great distances, observation capacity is limited, and operator actions and observations can be significantly delayed. Safe operations require support systems that provide situational understanding, enhance decision making, and facilitate collaboration between human operators and system automation both in-the-loop, and on-the-loop. Joint cognitive systems engineering (JCSE) provides a rich set of methods for analyzing and informing the design of complex systems that include both human decision-makers and autonomous elements as coordinating teammates. While, JCSE-based systems can enhance a system analysts' understanding of both existing and new system processes, JCSE activities typically occur outside of traditional systems engineering (SE) methods, providing sparse guidance about how systems should be implemented. In contrast, the Joint Director's Laboratory (JDL) information fusion model and extensions, such as the Dual Node Network (DNN) technical architecture, provide the means to divide and conquer such engineering and implementation complexity, but are loosely coupled to specialized organizational contexts and needs. We previously describe how Dual Node Decision Wheels (DNDW) extend the DNN to integrate JCSE analysis and design with the practicalities of system engineering and implementation using the DNN. Insights from Rasmussen's JCSE Decision Ladders align system implementation with organizational structures and processes. In the current work, we present a novel approach to assessing system performance based on patterns occurring in operational decisions that are documented by JCSE processes as traces in a decision ladder. In this way, system assessment is closely tied not just to system design, but the design of the joint cognitive system that includes human operators, decision-makers, information systems, and

  5. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...

  6. Small satellite attitude control for sun-oriented operations utilizing a momentum bias with magnetic actuators

    Science.gov (United States)

    Wolfe, Scott M.

    1995-03-01

    The feasibility of using a three axis control, momentum bias system with magnetic actuators for sun-oriented operations is explored. Relevant equations of motion are developed for a sun-oriented coordinate system and control laws are developed for initial spacecraft capture after launch vehicle separation; reorientation from Earth oriented to a sun oriented operations mode; sun-oriented attitude control; and momentum wheel control. Simulations demonstrating the stability and time responsiveness of the system are performed. Sensor noise input tests are performed to investigate the systems susceptibility to imperfect conditions. Cross product of inertia effects are also input to test for system instability.

  7. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... of the laboratory is to conduct dynamic tests of the control and attitude determination algorithms during nominal operation and in abnormal conditions. Further it is intended to use SatLab for validation of various algorithms for fault detection, accommodation and supervisory control. Different mission objectives...... can be implemented in the laboratory, e.g. three-axis attitude control, slew manoeuvres, spins stabilization using magnetic actuation and/or reaction wheels. The spacecraft attitude can be determined applying magnetometer measurements...

  8. Operating project for the Renardieres Power Laboratory: System structure. Acquisition and control satellites

    Energy Technology Data Exchange (ETDEWEB)

    Castagnet, D. (GIXI, 91 - Les Ulis (France))

    The principles and the construction of the new operating system for the Power Test Laboratory are presented. Emphasis is laid on the similarity between the project and Architecture 3 type remote operation systems, the electromagnetic disturbance and high safety level aspects and the utilization of microcomputers. After a presentation of the basic principles, modularity, standartization, safety, surroundings and maintenance, the article offers an explanation of the checking system structure, constituted by a central core and a network of industrial computers (SAC). These latter are described from the point of view of operations (remote-signalling, remote-control, remote-measurements, subsidiary functions), equipment structure (central processing unit, input and output boards) and reflections on the software (design, implementation, etc.).

  9. Implementing an operating room pharmacy satellite.

    Science.gov (United States)

    Powell, P J; Maland, L; Bair, J N; McCall, J D; Wong, K C

    1983-07-01

    Implementation of an operating room (OR) pharmacy satellite is described, and its impact on cost-effectiveness and efficiency of drug distribution is analyzed. The OR satellite provided pharmacy coverage for 30-35 patients per day in 10 centralized surgical suites, 2 obstetric suites, and 1 burn-unit suite in a 401-bed teaching hospital. Objectives of the satellite were to consolidate accountability for drug distribution and control, reduce controlled substance loss and waste, reduce inventory costs, and improve recording of patient charges. Stock on the OR supply cart was reduced, controlled substances were dispensed to anesthesiologists from the satellite, and a system of standardized anesthesiology exchange trays was developed. A new billing form served as both the charging document and replacement list. Reduction in the medication cart stock resulted in smaller discrepancies in patient charges. For the five most commonly used controlled substances, accounting discrepancies were reduced. Inventory turnover increased and inventory dollar value and cost per patient were reduced. The percent of nurses who believed that a pharmacist should work in the area increased from 31% before implementation of the satellite to 95% after. The pilot OR pharmacy satellite was a financial success. Efficiency and effectiveness in drug distribution and control were improved, and communication between pharmacists and other medical personnel working in the OR areas was enhanced.

  10. Enterprise Level Status and Control of Multi-Satellite Operations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to take information from multiple operational environments and securely deliver it in a graphically useful manner to the end user....

  11. Evaluation and modeling of autonomous attitude thrust control for the Geostation Operational Environmental Satellite (GOES)-8 orbit determination

    Science.gov (United States)

    Forcey, W.; Minnie, C. R.; Defazio, R. L.

    1995-01-01

    The Geostationary Operational Environmental Satellite (GOES)-8 experienced a series of orbital perturbations from autonomous attitude control thrusting before perigee raising maneuvers. These perturbations influenced differential correction orbital state solutions determined by the Goddard Space Flight Center (GSFC) Goddard Trajectory Determination System (GTDS). The maneuvers induced significant variations in the converged state vector for solutions using increasingly longer tracking data spans. These solutions were used for planning perigee maneuvers as well as initial estimates for orbit solutions used to evaluate the effectiveness of the perigee raising maneuvers. This paper discusses models for the incorporation of attitude thrust effects into the orbit determination process. Results from definitive attitude solutions are modeled as impulsive thrusts in orbit determination solutions created for GOES-8 mission support. Due to the attitude orientation of GOES-8, analysis results are presented that attempt to absorb the effects of attitude thrusting by including a solution for the coefficient of reflectivity, C(R). Models to represent the attitude maneuvers are tested against orbit determination solutions generated during real-time support of the GOES-8 mission. The modeling techniques discussed in this investigation offer benefits to the remaining missions in the GOES NEXT series. Similar missions with large autonomous attitude control thrusting, such as the Solar and Heliospheric Observatory (SOHO) spacecraft and the INTELSAT series, may also benefit from these results.

  12. Satellite Attitude Control System Simulator

    Directory of Open Access Journals (Sweden)

    G.T. Conti

    2008-01-01

    Full Text Available Future space missions will involve satellites with great autonomy and stringent pointing precision, requiring of the Attitude Control Systems (ACS with better performance than before, which is function of the control algorithms implemented on board computers. The difficulties for developing experimental ACS test is to obtain zero gravity and torque free conditions similar to the SCA operate in space. However, prototypes for control algorithms experimental verification are fundamental for space mission success. This paper presents the parameters estimation such as inertia matrix and position of mass centre of a Satellite Attitude Control System Simulator (SACSS, using algorithms based on least square regression and least square recursive methods. Simulations have shown that both methods have estimated the system parameters with small error. However, the least square recursive methods have performance more adequate for the SACSS objectives. The SACSS platform model will be used to do experimental verification of fundamental aspects of the satellite attitude dynamics and design of different attitude control algorithm.

  13. Wi-Fi and Satellite-Based Location Techniques for Intelligent Agricultural Machinery Controlled by a Human Operator

    Directory of Open Access Journals (Sweden)

    Domagoj Drenjanac

    2014-10-01

    Full Text Available In the new agricultural scenarios, the interaction between autonomous tractors and a human operator is important when they jointly perform a task. Obtaining and exchanging accurate localization information between autonomous tractors and the human operator, working as a team, is a critical to maintaining safety, synchronization, and efficiency during the execution of a mission. An advanced localization system for both entities involved in the joint work, i.e., the autonomous tractors and the human operator, provides a basis for meeting the task requirements. In this paper, different localization techniques for a human operator and an autonomous tractor in a field environment were tested. First, we compared the localization performances of two global navigation satellite systems’ (GNSS receivers carried by the human operator: (1 an internal GNSS receiver built into a handheld device; and (2 an external DGNSS receiver with centimeter-level accuracy. To investigate autonomous tractor localization, a real-time kinematic (RTK-based localization system installed on autonomous tractor developed for agricultural applications was evaluated. Finally, a hybrid localization approach, which combines distance estimates obtained using a wireless scheme with the position of an autonomous tractor obtained using an RTK-GNSS system, is proposed. The hybrid solution is intended for user localization in unstructured environments in which the GNSS signal is obstructed. The hybrid localization approach has two components: (1 a localization algorithm based on the received signal strength indication (RSSI from the wireless environment; and (2 the acquisition of the tractor RTK coordinates when the human operator is near the tractor. In five RSSI tests, the best result achieved was an average localization error of 4 m. In tests of real-time position correction between rows, RMS error of 2.4 cm demonstrated that the passes were straight, as was desired for the

  14. Effective management strategy for establishing an operating room satellite pharmacy.

    Science.gov (United States)

    Brakebill, J I; Schoeneman, P F; Buchanan, B

    1988-11-01

    The steps involved in justifying and implementing an operating room (OR) pharmacy satellite are described. A hospital administrator's viewpoint on the project is included. Objectives of the satellite were to reduce inventory costs, improve control of distribution, reduce loss of revenue and improve patient charging, improve IV compounding and labeling, and significantly improve narcotic control and accountability. The satellite provides comprehensive services 12 hours a day, five days a week. Effective after-hours procedures have been developed to provide efficient drug distribution when the pharmacy is closed. Achieved benefits of the satellite include decreased drug inventory, improved patient charging, accurate labeling, improved IV compounding, and improved pharmacy/surgery relations. The OR pharmacy satellite is a successful cost-effective operation.

  15. Polar Operational Environmental Satellites: Looking at Earth

    Science.gov (United States)

    Aleman, Roberto M.

    2000-01-01

    A broad overview of the Polar Operational Environmental Satellites (POES) Project is presented at a very high level. A general description of the scientific instruments on the Television Infrared Observational Satellite (TIROS) spacecraft is presented with emphasis put on their mission and the products derived from the data. Actual pictures produced from POES instruments data are shown to help the audience relate our work to their everyday life, as affected by the weather systems.

  16. Polar Operational Environmental Satellites: Looking at Earth

    Science.gov (United States)

    Aleman, Roberto M.

    2000-01-01

    A broad overview of the Polar Operational Environmental Satellites (POES) Project is presented at a very high level. A general description of the scientific instruments on the Television Infrared Observational Satellite (TIROS) spacecraft is presented with emphasis put on their mission and the products derived from the data. Actual pictures produced from POES instruments data are shown to help the audience relate our work to their everyday life, as affected by the weather systems.

  17. Extrapolating Satellite Winds to Turbine Operating Heights

    DEFF Research Database (Denmark)

    Badger, Merete; Pena Diaz, Alfredo; Hahmann, Andrea N.;

    2016-01-01

    Ocean wind retrievals from satellite sensors are typically performed for the standard level of 10 m. This restricts their full exploitation for wind energy planning, which requires wind information at much higher levels where wind turbines operate. A new method is presented for the vertical extra...

  18. Uses of communication satellites in water utility operations

    Science.gov (United States)

    Tighe, W. S.

    This paper proposes a system to serve the communications needs of the operating side of a water utility and estimates the requirements and capabilities of the equipment needed. The system requires the shared use of a satellite transponder with 100% backup. Messages consist of data packets containing data and control information, plus voice transmission. Satellite communication may have a price advantage in some instances over wire line or VHF radio and have greater survivability in case of a natural disaster. Water and other utilities represent a significant market for low cost mass produced satellite earth terminals.

  19. Operational evapotranspiration based on Earth observation satellites

    Science.gov (United States)

    Gellens-Meulenberghs, Françoise; Ghilain, Nicolas; Arboleda, Alirio; Barrios, Jose-Miguel

    2016-04-01

    Geostationary satellites have the potential to follow fast evolving atmospheric and Earth surface phenomena such those related to cloud cover evolution and diurnal cycle. Since about 15 years, EUMETSAT has set up a network named 'Satellite Application Facility' (SAF, http://www.eumetsat.int/website/home/Satellites/GroundSegment/Safs/index.html) to complement its ground segment. The Land Surface Analysis (LSA) SAF (http://landsaf.meteo.pt/) is devoted to the development of operational products derived from the European meteorological satellites. In particular, an evapotranspiration (ET) product has been developed by the Royal Meteorological Institute of Belgium. Instantaneous and daily integrated results are produced in near real time and are freely available respectively since the end of 2009 and 2010. The products cover Europe, Africa and the Eastern part of South America with the spatial resolution of the SEVIRI sensor on-board Meteosat Second Generation (MSG) satellites. The ET product algorithm (Ghilain et al., 2011) is based on a simplified Soil-Vegetation-Atmosphere transfer (SVAT) scheme, forced with MSG derived radiative products (LSA SAF short and longwave surface fluxes, albedo). It has been extensively validated against in-situ validation data, mainly FLUXNET observations, demonstrating its good performances except in some arid or semi-arid areas. Research has then been pursued to develop an improved version for those areas. Solutions have been found in reviewing some of the model parameterizations and in assimilating additional satellite products (mainly vegetation indices and land surface temperature) into the model. The ET products will be complemented with related latent and sensible heat fluxes, to allow the monitoring of land surface energy partitioning. The new algorithm version should be tested in the LSA-SAF operational computer system in 2016 and results should become accessible to beta-users/regular users by the end of 2016/early 2017. In

  20. An operational satellite remote sensing system for ocean fishery

    Institute of Scientific and Technical Information of China (English)

    MAOZhihua; ZHUQiankun; PANDelu

    2004-01-01

    Ocean environmental information is very important to supporting the fishermen in fishing and satellite remote sensing technology can provide it in large scale and in near real-time. Ocean fishery locations are always far away beyond the coverage of the satellite data received by a land-based satellite receiving station. A nice idea is to install the satellite ground station on a fishing boat. When the boat moves to a fishery location, the station can receive the satellite data to cover the fishery areas. One satellite remote sensing system was once installed in a fishing boat and served fishing in the North Pacific fishery areas when the boat stayed there. The system can provide some oceanic environmental charts such as sea surface temperature (SST) and relevant derived products which are in most popular use in fishery industry. The accuracy of SST is the most important and affects the performance of the operational system, which is found to be dissatisfactory. Many factors affect the accuracy of SST and it is difficult to increase the accuracy by SST retrieval algorithms and clouds detection technology. A new technology of temperature error control is developed to detect the abnormity of satellite-measured SST. The performance of the technology is evaluated to change the temperature bias from-3.04 to 0.05 ℃ and the root mean square (RMS) from 5.71 to 1.75 ℃. It is suitable for employing in an operational satellite-measured SST system and improves the performance of the system in fishery applications. The system has been running for 3 a and proved to be very useful in fishing. It can help to locate the candidates of the fishery areas and monitor the typhoon which is very dangerous to the safety of fishing boats.

  1. Efficient mission control for the 48-satellite Globalstar Constellation

    Science.gov (United States)

    Smith, Dan

    1994-11-01

    The Globalstar system is being developed by Globalstar, Limited Partnership and will utilize 48 satellites in low earth orbit (See Figure 1) to create a world-wide mobile communications system consistent with Vice President Gore's vision of a Global Information Infrastructure. As a large long term commercial system developed by a newly formed organization, Globalstar provides an excellent opportunity to explore innovative solutions for highly efficient satellite command and control. Design and operational concepts being developed are unencumbered by existing physical and organizational infrastructures. This program really is 'starting with a clean sheet of paper'. Globalstar operations challenges can appear enormous. Clearly, assigning even a single person around the clock to monitor and control each satellite is excessive for Globalstar (it would require a staff of 200] . Even with only a single contact per orbit per satellite, data acquisitions will start or stop every 45 seconds] Although essentially identical, over time the satellites will develop their own 'personalities'and will re quire different data calibrations and levels of support. This paper discusses the Globalstar system and challenges and presents engineering concepts, system design decisions, and operations concepts which address the combined needs and concerns of satellite, ground system, and operations teams. Lessons from past missions have been applied, organizational barriers broken, partnerships formed across the mission segments, and new operations concepts developed for satellite constellation management. Control center requirements were then developed from the operations concepts.

  2. Autonomous robotic operations for on-orbit satellite servicing

    Science.gov (United States)

    Ogilvie, Andrew; Allport, Justin; Hannah, Michael; Lymer, John

    2008-04-01

    The Orbital Express Demonstration System (OEDS) flight test successfully demonstrated technologies required to autonomously service satellites on-orbit. The mission's integrated robotics solution, the Orbital Express Demonstration Manipulator System (OEDMS) developed by MDA, performed critical flight test operations. The OEDMS comprised a six-jointed robotic manipulator arm and its avionics, non-proprietary servicing and ORU (Orbital Replacement Unit) interfaces, a vision and arm control system for autonomous satellite capture, and a suite of Ground Segment and Flight Segment software allowing script generation and execution under supervised or full autonomy. The arm was mounted on ASTRO, the servicer spacecraft developed by Boeing. The NextSat, developed by Ball Aerospace, served as the client satellite. The OEDMS demonstrated two key goals of the OEDS flight test: autonomous free-flyer capture and berthing of a client satellite, and autonomous transfer of ORUs from servicer to client and back. The paper provides a description of the OEDMS and the key operations it performed.

  3. Use of Earth Observing Satellites for Operational Hazard Support

    Science.gov (United States)

    Wood, H. M.; Lauritson, L.

    The National Oceanic and Atmospheric Administration (NOAA) relies on Earth observing satellite data to carry out its operational mission to monitor, predict, and assess changes in the Earth's atmosphere, land, and oceans. NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) uses satellite data to help lessen the impacts of natural and man-made disasters due to tropical cyclones, flash floods, heavy snowstorms, volcanic ash clouds (for aviation safety), sea ice (for shipping safety), and harmful algal blooms. Communications systems on NOAA satellites are used to support search and rescue and to relay data from data collection platforms to a variety of users. NOAA's Geostationary (GOES) and Polar (POES) Operational Environmental Satellites are used in conjunction with other satellites to support NOAA's operational mission. While NOAA's National Hurricane Center is responsible for predicting tropical cyclones affecting the U.S. mainland, NESDIS continuously monitors the tropics world wide, relaying valuable satellite interpretations of tropical systems strength and position to users throughout the world. Text messages are sent every six hours for tropical cyclones in the Western Pacific, South Pacific, and Indian Oceans. To support the monitoring, prediction, and assessment of flash floods and winter storms, NESDIS sends out text messages alerting U.S. weather forecast offices whenever NOAA satellite imagery indicates the occurrence of heavy rain or snow. NESDIS also produces a 24-hour rainfall composite graphic image covering those areas affected by heavy precipitation. The International Civil Aviation Organization (ICAO) and other aviation concerns recognized the need to keep aviators informed of volcanic hazards. To that end, nine Volcanic Ash Advisory Centers (VAAC's) were created to monitor volcanic ash plumes within their assigned airspace. NESDIS hosts one of the VAAC's. Although the NESDIS VAAC's primary responsibility is the

  4. Communication Satellites: Experimental & Operational, Commercial & Public Service.

    Science.gov (United States)

    Development Communication Report, 1979

    1979-01-01

    The title reflects the first and major article in an issue of this newsletter devoted entirely to communication satellites. This series of articles on the potential and applications of communication satellites in development projects is concerned with their development for commercial and public service, development in the Pacific region, SPACECOM…

  5. Satellite Attitude Control Using Only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    The primary purpose of this work was to develop control laws for three axis stabilization of a magnetic actuated satellite. This was achieved by a combination of linear and nonlinear system theory. In order to reach this goal new theoretical results were produced in both fields. The focus...... was that interaction between the Earth's magnetic field and a magnetic field generated by a set of coils in the satellite can be used for actuation. Magnetic torquing was found attractive for generation of control torques on small satellites, since magnetic control systems are relatively lightweight, require low power...... was stated as a continuous function of the state. A control law for magnetic actuated satellite was proposed. Complete comprehension of the nature of the satellite control problem required a new approach merging the nonlinear control theory with physics of the rigid body motion and an extension of earlier...

  6. Tracking and data relay satellite system configuration and tradeoff study. Volume 4: TDRS system operation and control and telecommunications service system, part 1

    Science.gov (United States)

    1972-01-01

    Major study areas treated in this volume are: 1) operations and control and 2) the telecommunication service system. The TDRS orbit selection, orbital deployment, ground station visibility, sequence of events from launch to final orbit position, and TDRS control center functions required for stationkeeping, repositioning, attitude control, and antenna pointing are briefly treated as part of the operations and control section. The last topic of this section concerns the operations required for efficiently providing the TDRSS user telecommunication services. The discussion treats functions of the GSFC control and data processing facility, ground station, and TDRS control center. The second major portion of this volume deals with the Telecommunication Service System (TSS) which consists of the ground station, TDRS communication equipment and the user transceiver. A summary of the requirements and objectives for the telecommunication services and a brief summary of the TSS capabilities is followed by communication system analysis, signal design, and equipment design. Finally, descriptions of the three TSS elements are presented.

  7. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    Science.gov (United States)

    Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

    1996-01-01

    This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

  8. Lorentz Force Based Satellite Attitude Control

    Science.gov (United States)

    Giri, Dipak Kumar; Sinha, Manoranjan

    2016-07-01

    Since the inception of attitude control of a satellite, various active and passive control strategies have been developed. These include using thrusters, momentum wheels, control moment gyros and magnetic torquers. In this present work, a new technique named Lorentz force based Coulombic actuators for the active control is proposed. This method uses electrostatic charged shells, which interact with the time varying earth's magnetic field to establish a full three axes control of the satellite. It is shown that the proposed actuation mechanism is similar to a satellite actuated by magnetic coils except that the resultant magnetic moment vanishes under two different conditions. The equation for the required charges on the the Coulomb shells attached to the satellite body axes is derived, which is in turn used to find the available control torque for actuating the satellite along the orbit. Stability of the proposed system for very high initial angular velocity and exponential stability about the origin are proved for a proportional-differential control input. Simulations are carried out to show the efficacy of the proposed system for the attitude control of the earth-pointing satellite.

  9. NOAA Geostationary Operational Environmental Satellite (GOES) Imager Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA Geostationary Operational Environmental Satellite (GOES) series provides continuous measurements of the atmosphere and surface over the Western Hemisphere....

  10. Models for estimation of land remote sensing satellites operational efficiency

    Science.gov (United States)

    Kurenkov, Vladimir I.; Kucherov, Alexander S.

    2017-01-01

    The paper deals with the problem of estimation of land remote sensing satellites operational efficiency. Appropriate mathematical models have been developed. Some results obtained with the help of the software worked out in Delphi programming support environment are presented.

  11. NOAA Polar-orbiting Operational Environmental Satellites (POES) Radiometer Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Polar-orbiting Operational Environmental Satellite (POES) series offers the advantage of daily global coverage, by making nearly polar orbits 14 times per day...

  12. Smaller Satellite Operations Near Geostationary Orbit

    Science.gov (United States)

    2007-09-01

    Hubble_Space_Telescope>. 29 Heiner Klinkrad . Space Debris: Models and Risk Analysis. Chichester, UK. Springer, 2006. 32. 31 threshold, the satellites would be...Heiner Klinkrad . Space Debris: Models and Risk Analysis. Chichester, UK. Springer, 2006. 32. 35 Appendix B. 39 throughout such a maneuver36, which...46 Heiner Klinkrad . Space Debris: Models and Risk Analysis. Chichester, UK. Springer, 2006. 32. 47 S. Kilston. Ikonos-2, Block-1

  13. Statistical Design Model (SDM) of satellite thermal control subsystem

    Science.gov (United States)

    Mirshams, Mehran; Zabihian, Ehsan; Aarabi Chamalishahi, Mahdi

    2016-07-01

    Satellites thermal control, is a satellite subsystem that its main task is keeping the satellite components at its own survival and activity temperatures. Ability of satellite thermal control plays a key role in satisfying satellite's operational requirements and designing this subsystem is a part of satellite design. In the other hand due to the lack of information provided by companies and designers still doesn't have a specific design process while it is one of the fundamental subsystems. The aim of this paper, is to identify and extract statistical design models of spacecraft thermal control subsystem by using SDM design method. This method analyses statistical data with a particular procedure. To implement SDM method, a complete database is required. Therefore, we first collect spacecraft data and create a database, and then we extract statistical graphs using Microsoft Excel, from which we further extract mathematical models. Inputs parameters of the method are mass, mission, and life time of the satellite. For this purpose at first thermal control subsystem has been introduced and hardware using in the this subsystem and its variants has been investigated. In the next part different statistical models has been mentioned and a brief compare will be between them. Finally, this paper particular statistical model is extracted from collected statistical data. Process of testing the accuracy and verifying the method use a case study. Which by the comparisons between the specifications of thermal control subsystem of a fabricated satellite and the analyses results, the methodology in this paper was proved to be effective. Key Words: Thermal control subsystem design, Statistical design model (SDM), Satellite conceptual design, Thermal hardware

  14. Adaptive Fuzzy Attitude Control of Flexible Satellite

    Institute of Scientific and Technical Information of China (English)

    GUAN Ping; LIU Xiang-dong; CHEN Jia-bin

    2005-01-01

    The adaptive fuzzy control is applied in the attitude stabilization of flexible satellite. The detailed design procedure of the adaptive fuzzy control system is presented. Two T-S models are used as both controller and identifier. The parameters of the controller could be modified according to the information of the identifier. Simulation results show that the method can effectively cope with the uncertainty of flexible satellite by on-line learning and thus posses the good robustness. With the proposed method, the precise attitude control is accomplished.

  15. On-orbit control of the Communications Technology Satellite (CTS)/HERMES

    Science.gov (United States)

    Raine, H. R.

    1980-01-01

    A variety of control functions for the CIS HERMES satellite are reviewed. Its mission, to demonstrate high power SHF (12 GHz) transmission is discussed. The satellite was controlled in geostationary orbit for nearly four years from the satellite control center in Ottawa, Canada. Highlights of these operations are outlined. The interactions between many of the automatic onboard control functions and control from the ground are described. Special emphasis is placed on the characteristics and performance of the three axis attitude control system.

  16. Digital frequency control of satellite frequency standards. [Defense Navigation Satellites

    Science.gov (United States)

    Nichols, S. A.

    1973-01-01

    In the Frequency and Time Standard Development Program of the TIMATION System, a new miniaturized rubidium vapor frequency standard has been tested and analyzed for possible use on the TIMATION 3A launch, as part of the Defense Navigation Satellite Development Program. The design and construction of a digital frequency control was required to remotely control this rubidium vapor frequency standard as well as the quartz oscillator in current use. This control must be capable of accepting commands from a satellite telemetry system, verify that the correct commands have been sent and control the frequency to the requirements of the system. Several modifications must be performed to the rubidium vapor frequency standard to allow it to be compatible with the digital frequency control. These include the addition of a varactor to voltage tune the coarse range of the flywheel oscillator, and a modification to supply the C field current externally. The digital frequency control for the rubidium vapor frequency standard has been successfully tested in prototype form.

  17. Adaptive Control of Rigid Body Satellite

    Institute of Scientific and Technical Information of China (English)

    Thawar T. Arif

    2008-01-01

    The minimal controller synthesis (MCS) is an extension of the hyperstable model reference adaptive control algorithm. The aim of minimal controller synthesis is to achieve excellent closed-loop control despite the presence of plant parameter variations, external disturbances, dynamic coupling within the plant and plant nonlinearities. The minimal controller synthesis algorithm was successfully applied to the problem of decentralized adaptive schemes. The decentralized minimal controller synthesis adaptive control strategy for controlling the attitude of a rigid body satellite is adopted in this paper. A model reference adaptive control strategy which uses one single three-axis slew is proposed for the purpose of controlling the attitude of a rigid body satellite. The simulation results are excellent and show that the controlled system is robust against disturbances.

  18. Snowline retrievals using operational satellite data

    Science.gov (United States)

    Becker, R.

    2010-09-01

    Making use of atmosphere and surface parameters derived from satellite remote sensing is of increasing importance to describe appropriately status and changes of weather and climate. Even in regions with poor coverage concerning ground based measurements and/or heterogenous terrain satellite products contribute to fill temporal and spatial gaps. Imaging radiometers provide information on surface snow and ice based on multispectral algorithms with a spatial resolution from 250 m to about 3000 m. Observations by passive imaging spectro-/radiometers like SEVIRI onboard Meteosat second generation, Noaa/MetOp AVHRR and Terra/Aqua MODIS have the potential to provide snow products on a daily basis with spatial resolution comparable or better than grid increment of the hydrological models. For the evaluation of MODIS imagery a dedicated algorithm was set up utilising multispectral thresholding of calibrated radiances to separate clear land and sea from cloudy and snow-covered scenes. The scheme works independently of a-priori atmospheric data like numerical model forecasts. It outputs a combined snow/cloudmask that is finally convoluted with background topography information (GIS), allowing for the calculation of snowlines. The core snow and ice detection is based on a NDSI module (normalised difference snow index, Hall et.al. 2001). A well established algorithm developed within the framework of the Satellite Application Facility for Nowcasting (NWCSAF, Dybbroe et.al. 2005), is used to detect snowy pixels in the AVHRR imagery. MODIS and AVHRR results were compared to each other. It shows a good agreement by means of correlation (.94) but systematic deviations are considered. A verification study was carried out by taking into account all European synoptical and climatological snow measurements with snow depths of at least 1 cm. The scores show a clear seasonal cycle with PODs of .2 in summer (both) and .86 (AVHRR) and .82 (MODIS) in winter months. The evaluation data

  19. Onboard Supervisor for the Ørsted Satellite Attitude Control System

    DEFF Research Database (Denmark)

    Bøgh, S.A.; Izadi-Zamanabadi, Roozbeh; Blanke, M.

    1995-01-01

    The increasing operational requirements for onboard autonomy in satellite control systems necessitates structural methods that support the design of a complete and reliable supervisory system.......The increasing operational requirements for onboard autonomy in satellite control systems necessitates structural methods that support the design of a complete and reliable supervisory system....

  20. Geostationary Operational Environmental Satellite (GOES)-8 mission flight experience

    Science.gov (United States)

    Noonan, C. H.; McIntosh, R. J.; Rowe, J. N.; Defazio, R. L.; Galal, K. F.

    1995-05-01

    The Geostationary Operational Environmental Satellite (GOES)-8 spacecraft was launched on April 13, 1994, at 06:04:02 coordinated universal time (UTC), with separation from the Atlas-Centaur launch vehicle occurring at 06:33:05 UTC. The launch was followed by a series of complex, intense operations to maneuver the spacecraft into its geosynchronous mission orbit. The Flight Dynamics Facility (FDF) of the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) was responsible for GOES-8 attitude, orbit maneuver, orbit determination, and station acquisition support during the ascent phase. This paper summarizes the efforts of the FDF support teams and highlights some of the unique challenges the launch team faced during critical GOES-8 mission support. FDF operations experience discussed includes: (1) The abort of apogee maneuver firing-1 (AMF-1), cancellation of AMF-3, and the subsequent replans of the maneuver profile; (2) The unexpectedly large temperature dependence of the digital integrating rate assembly (DIRA) and its effect on GOES-8 attitude targeting in support of perigee raising maneuvers; (3) The significant effect of attitude control thrusting on GOES-8 orbit determination solutions; (4) Adjustment of the trim tab to minimize torque due to solar radiation pressure; and (5) Postlaunch analysis performed to estimate the GOES-8 separation attitude. The paper also discusses some key FDF GOES-8 lessons learned to be considered for the GOES-J launch which is currently scheduled for May 19, 1995.

  1. The National Polar-orbiting Operational Environmental Satellite System

    Science.gov (United States)

    Bloom, H.

    The tri-agency Integrated Program Office (IPO) is responsible for managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS will replace the current military and civilian operational polar-orbiting ``weather'' satellites. The Northrop Grumman Space Technology - Raytheon team was competitively selected in 2002 as the Acquisition and Operations contractor team to develop, integrate, deploy, and operate NPOESS satellites to meet the tri-agency user requirements for NPOESS over the 10-year (2009-2018) operational life of the program. Beginning in 2009, NPOESS spacecraft will be launched into three orbital planes to provide significantly improved operational capabilities and benefits to satisfy critical civil and national security requirements for space-based, remotely sensed environmental data. With the development of NPOESS, we are evolving operational ``weather'' satellites into integrated environmental observing systems by expanding our capabilities to observe, assess, and predict the total Earth system - atmosphere, ocean, land, and the space environment. In recent years, the operational weather forecasting and climate science communities have levied more rigorous requirements on space-based observations of the Earth's system that have significantly increased demands on performance of the instruments, spacecraft, and ground systems required to deliver NPOESS data, products, and information to end users. The ``end-to-end'' system consists of: the spacecraft; instruments and sensors on the spacecraft; launch support capabilities; the command, control, communications, and data routing infrastructure; and data processing hardware and software. NPOESS will observe significantly more phenomena simultaneously from space than its operational predecessors. NPOESS is expected to deliver large volumes of more accurate measurements at higher spatial (horizontal and vertical) and temporal resolution at much higher data

  2. Silicon avalanche photodiode operation and lifetime analysis for small satellites.

    Science.gov (United States)

    Tan, Yue Chuan; Chandrasekara, Rakhitha; Cheng, Cliff; Ling, Alexander

    2013-07-15

    Silicon avalanche photodiodes (APDs) are sensitive to operating temperature fluctuations and are also susceptible to radiation flux expected in satellite-based quantum experiments. We introduce a low power voltage adjusting mechanism to overcome the effects of in-orbit temperature fluctuations. We also present data on the performance of Si APDs after irradiation (γ-ray and proton beam). Combined with an analysis of expected orbital irradiation, we propose that a Si APD in a 400 km equatorial orbit may operate beyond the lifetime of the satellite.

  3. Silicon avalanche photodiode operation and lifetime analysis for small satellites

    CERN Document Server

    Tan, Yue Chuan; Cheng, Cliff; Ling, Alexander

    2013-01-01

    Silicon avalanche photodiodes (APDs) are sensitive to operating temperature fluctuations and are also susceptible to radiation flux expected in satellite-based quantum experiments. We introduce a low power voltage adjusting mechanism to overcome the effects of in-orbit temperature fluctuations. We also present data on the performance of Si APDs after irradiation (gamma-ray and proton beam). Combined with an analysis of expected orbital irradiation, we propose that a Si APD in a 400 km equatorial orbit may operate beyond the lifetime of the satellite.

  4. Integrating Balloon and Satellite Operation Data Centers for Technology Readiness Assessment

    Science.gov (United States)

    Mattiello-Francisco, Fátima; Fernandes, Jose Oscar

    2016-07-01

    Stratospheric balloon-borne experiments have been one of the most effective ways to validate innovative space technology, taking the advantage of reduced development cycles and low cost in launching and operation. In Brazil, the National Institute for Space Research (INPE) has balloon and satellite ground infrastructures since the 1970´s and the 1990´s, respectively. In the recent past, a strategic approach was adopted on the modernization of balloon ground operation facilities for supporting the protoMIRAX experiment, an X-ray imaging telescope under development at INPE as a pathfinder for the MIRAX (Monitor e Imageador de Raios X) satellite mission. The strategic target was to reuse the SATellite Control System (SATCS), a software framework developed to control and monitor INPÉs satellites, for balloon operation. This paper presents the results of that effort and the new ongoing project, a computer-based framework named I2Bso, which strategic target is to Integrate INPÉs Balloon and Satellite Operation data centers. The I2Bso major purpose is to support the continuous assessment of an innovative technology after different qualification flights either on board balloons or satellites in order to acquire growing evidence for the technology maturity.

  5. Chaotic satellite attitude control by adaptive approach

    Science.gov (United States)

    Wei, Wei; Wang, Jing; Zuo, Min; Liu, Zaiwen; Du, Junping

    2014-06-01

    In this article, chaos control of satellite attitude motion is considered. Adaptive control based on dynamic compensation is utilised to suppress the chaotic behaviour. Control approaches with three control inputs and with only one control input are proposed. Since the adaptive control employed is based on dynamic compensation, faithful model of the system is of no necessity. Sinusoidal disturbance and parameter uncertainties are considered to evaluate the robustness of the closed-loop system. Both of the approaches are confirmed by theoretical and numerical results.

  6. Controlling chaos in a satellite power supply subsystem

    Science.gov (United States)

    Macau, E. E. N.; Ramos Turci, L. F.; Yoneyama, T.

    2008-12-01

    In this work, we show that chaos control techniques can be used to increase the region that can be efficiently used to supply the power requests for an artificial satellite. The core of a satellite power subsystem relies on its DC/DC converter. This is a very nonlinear system that presents a multitude of phenomena ranging from bifurcations, quasi-periodicity, chaos, coexistence of attractors, among others. The traditional power subsystem design techniques try to avoid these nonlinear phenomena so that it is possible to use linear system theory in small regions about the equilibrium points. Here, we show that chaos control can be used to efficiently extend the applicability region of the satellite power subsystem when it operates in regions of high nonlinearity.

  7. Assessment of breakup severity on operational satellites

    Science.gov (United States)

    Letizia, Francesca; Colombo, Camilla; Lewis, Hugh G.; Krag, Holger

    2016-10-01

    In the past years, several methods have been proposed to rank spacecraft and space debris objects depending on their effect on the space environment. The interest in this kind of indices is primarily motivated by the need of prioritising potential candidates of active debris removal missions and to decide on the required reliability for disposal actions during the design phase. The index proposed in this work measures the effect of the catastrophic fragmentation of the analysed spacecraft in terms of the resulting collision probability for operational spacecraft. The propagation of the debris cloud generated by the fragmentation and the estimation of the collision probability are obtained by applying an analytical approach based on the study of the density of the fragment cloud. The dependence of the proposed severity index on the mass of the spacecraft and on its semi-major axis and inclination is investigated. The index was computed for the objects in the DISCOS database and its results were compared to other formulations proposed in literature. A discussion on the results and on the comparison is presented.

  8. Introducing you to satellite operated data collection platforms (DCP).

    CSIR Research Space (South Africa)

    Stavropoulos, CC

    1977-09-01

    Full Text Available using this form of repeater. However, satellites able to handle reports from data collection platform (DCP's) have hitherto only been experimental. Within the next two years the operational phase for this type of activity will have been reached...

  9. Congestion control and routing over satellite networks

    Science.gov (United States)

    Cao, Jinhua

    Satellite networks and transmissions find their application in fields of computer communications, telephone communications, television broadcasting, transportation, space situational awareness systems and so on. This thesis mainly focuses on two networking issues affecting satellite networking: network congestion control and network routing optimization. Congestion, which leads to long queueing delays, packet losses or both, is a networking problem that has drawn the attention of many researchers. The goal of congestion control mechanisms is to ensure high bandwidth utilization while avoiding network congestion by regulating the rate at which traffic sources inject packets into a network. In this thesis, we propose a stable congestion controller using data-driven, safe switching control theory to improve the dynamic performance of satellite Transmission Control Protocol/Active Queue Management (TCP/AQM) networks. First, the stable region of the Proportional-Integral (PI) parameters for a nominal model is explored. Then, a PI controller, whose parameters are adaptively tuned by switching among members of a given candidate set, using observed plant data, is presented and compared with some classical AQM policy examples, such as Random Early Detection (RED) and fixed PI control. A new cost detectable switching law with an interval cost function switching algorithm, which improves the performance and also saves the computational cost, is developed and compared with a law commonly used in the switching control literature. Finite-gain stability of the system is proved. A fuzzy logic PI controller is incorporated as a special candidate to achieve good performance at all nominal points with the available set of candidate controllers. Simulations are presented to validate the theory. An effocient routing algorithm plays a key role in optimizing network resources. In this thesis, we briefly analyze Low Earth Orbit (LEO) satellite networks, review the Cross Entropy (CE

  10. Satellite Formation Control Using Atmospheric Drag

    Science.gov (United States)

    2007-03-01

    all cases tested, and the eccentricity-minimizing control law was able to maintain the position within 4.17 feet. More recently, Wedekind considered...three different formations, in-plane, in-track, and circular, was considered. Wedekind achieved favorable results for these three formations when the...and Kluwer Academic Publishers, 2004. 23. Wedekind , James T. Characterizing and Controlling the Effects of Differential Drag on Satellite Formations

  11. Small Satellite Passive Magnetic Attitude Control

    Science.gov (United States)

    Gerhardt, David T.

    Passive Magnetic Attitude Control (PMAC) is capable of aligning a satellite within 5 degrees of the local magnetic field at low resource cost, making it ideal for a small satellite. However, simulation attempts to date have not been able to predict the attitude dynamics at a level sufficient for mission design. Also, some satellites have suffered from degraded performance due to an incomplete understanding of PMAC system design. This dissertation alleviates these issues by discussing the design, inputs, and validation of PMAC systems for small satellites. Design rules for a PMAC system are defined using the Colorado Student Space Weather Experiment (CSSWE) CubeSat as an example. A Multiplicative Extended Kalman Filter (MEKF) is defined for the attitude determination of a PMAC satellite without a rate gyro. After on-orbit calibration of the off-the-shelf magnetometer and photodiodes and an on-orbit fit to the satellite magnetic moment, the MEKF regularly achieves a three sigma attitude uncertainty of 4 degrees or less. CSSWE is found to settle to the magnetic field in seven days, verifying its attitude design requirement. A Helmholtz cage is constructed and used to characterize the CSSWE bar magnet and hysteresis rods both individually and in the flight configuration. Fitted parameters which govern the magnetic material behavior are used as input to a PMAC dynamics simulation. All components of this simulation are described and defined. Simulation-based dynamics analysis shows that certain initial conditions result in abnormally decreased settling times; these cases may be identified by their dynamic response. The simulation output is compared to the MEKF output; the true dynamics are well modeled and the predicted settling time is found to possess a 20 percent error, a significant improvement over prior simulation.

  12. Incoherent correlator system for satellite orientation control

    Science.gov (United States)

    Kouris, Aristodemos; Young, Rupert C. D.; Chatwin, Christopher R.; Birch, Philip M.

    2002-03-01

    An incoherent correlator configuration is proposed and experimentally demonstrated that is capable of recognizing star patterns. The device may thus be employed for the orientation and navigation of a satellite or spacecraft. The correlator employs starlight directly and requires no laser or input spatial light modulator for operation. The filter is constructed form an array of mirrors that may be individually appropriately tilted so as recognize a particular star arrangement. The only other components of the system are a converging lens and CCD array detector. The device is capable of determining the pointing direction and rotation of a satellite or space vehicle. Experimental results employing the mirror array device illuminated with a point source early to simulate starlight are presented.

  13. Satellite Attitude Control Using Atmospheric Drag

    Science.gov (United States)

    2007-03-01

    Astronautics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In...yaw axes and provide magnetic damping on both the pitch and yaw axes. The satellite resem- bles a shuttlecock used in badminton (see Figure 2.2). The...Control Using Atmospheric Drag Guettler, David B., Captain, USAF Air Force Institute of Technology Graduate School of Engineering and Management (AFIT

  14. A Challenging Trio in Space 'Routine' Operations of the Swarm Satellite Constellation

    Science.gov (United States)

    Diekmann, Frank-Jurgen; Clerigo, Ignacio; Albini, Giuseppe; Maleville, Laurent; Neto, Alessandro; Patterson, David; Nino, Ana Piris; Sieg, Detlef

    2016-08-01

    Swarm is the first ESA Earth Observation Mission with three satellites flying in a semi-controlled constellation. The trio is operated from ESA's satellite control centre ESOC in Darmstadt, Germany. The Swarm Flight Operations Segment consists of the typical elements of a satellite control system at ESOC, but had to be carefully tailored for this innovative mission. The main challenge was the multi-satellite system of Swarm, which necessitated the development of a Mission Control System with a multi-domain functionality, both in hardware and software and covering real-time and backup domains. This was driven by the need for extreme flexibility for constellation operations and parallel activities.The three months of commissioning in 2014 were characterized by a very tight and dynamically changing schedule of activities. All operational issues could be solved during that time, including the challenging orbit acquisition phase to achieve the final constellation.Although the formal spacecraft commissioning phase was concluded in spring 2014, the investigations for some payload instruments continue even today. The Electrical Field Instruments are for instance still being tested in order to characterize and improve science data quality. Various test phases also became necessary for the Accelerometers on the Swarm satellites. In order to improve the performance of the GPS Receivers for better scientific exploitation and to minimize the failures due to loss of synchronization, a number of parameter changes were commanded via on-board patches.Finally, to minimize the impact on operations, a new strategy had to be implemented to handle single/multi bit errors in the on-board mass Memories, defining when to ignore and when to restore the memory via a re-initialisation.The poster presentation summarizes the Swarm specific ground segment elements of the FOS and explains some of the extended payload commissioning operations, turning Swarm into a most demanding and challenging

  15. Operational high latitude surface irradiance products from polar orbiting satellites

    Science.gov (United States)

    Godøy, Øystein

    2016-12-01

    It remains a challenge to find an adequate approach for operational estimation of surface incoming short- and longwave irradiance at high latitudes using polar orbiting meteorological satellite data. In this presentation validation results at a number of North Atlantic and Arctic Ocean high latitude stations are presented and discussed. The validation results have revealed that although the method works well and normally fulfil the operational requirements, there is room for improvement. A number of issues that can improve the estimates at high latitudes have been identified. These improvements are partly related to improved cloud classification using satellite data and partly related to improved handling of multiple reflections over bright surfaces (snow and sea ice), especially in broken cloud conditions. Furthermore, the availability of validation sites over open ocean and sea ice is a challenge.

  16. Operational monitoring of turbidity in rivers: how satellites can contribute

    Science.gov (United States)

    Hucke, Dorothee; Hillebrand, Gudrun; Winterscheid, Axel; Kranz, Susanne; Baschek, Björn

    2016-10-01

    The applications of remote sensing in hydrology are diverse and offer significant benefits for water monitoring. Up to now, operational river monitoring and sediment management in Germany mainly rely on in-situ measurements and on results obtained from numerical modelling. Remote sensing by satellites has a great potential to supplement existing data with two-dimensional information on near-surface turbidity distributions at greater spatial scales than in-situ measurements can offer. Within the project WasMon-CT (WaterMonitoring-Chlorophyll/Turbidity), the Federal Institute of Hydrology (BfG) aims at the implementation of an operational monitoring of turbidity distributions based on satellite images (esp. Sentinel-2, Landsat7 and 8). Initially, selected federal inland and estuarine waterways will be addressed: Rhine, Elbe, Ems, Weser. WasMon-CT is funded within the German Copernicus activities. Within the project, a database of atmospherically corrected, geo-referenced turbidity data will be assembled. The collected corresponding meta-data will include aspects of satellite data as well as hydrological data, e.g. cloud cover and river run-off. Based on this catalogue of spatially linked meta-data, the satellite data will be selected by e.g. cloud cover or run-off. The permanently updated database will include past as well as recent satellite images. It is designed with a long-term perspective to optimize the existing in-situ measurement network, which will serve partly for calibration and partly as validation data set. The aim is to extend, but not to substitute, the existing frequent point measurements with spatially extensive, satellite-derived data from the near surface part of the water column. Here, turbidity is used as proxy for corresponding suspended sediment concentrations. For this, the relationship between turbidity and suspended sediment concentrations will be investigated. Products as e.g. longitudinal profiles or virtual measurement stations will be

  17. Science operations management. [with Infrared Astronomy Satellite project

    Science.gov (United States)

    Squibb, G. F.

    1984-01-01

    The operation teams engaged in the IR Astronomical Satellite (IRAS) project included scientists from the IRAS International Science Team. The detailed involvement of these scientists in the design, testing, validation, and operations phases of the IRAS mission contributed to the success of this project. The Project Management Group spent a substantial amount of time discussing science-related issues, because science team coleaders were members from the outset. A single scientific point-of-contact for the Management Group enhanced the depth and continuity of agreement reached in decision-making.

  18. A new algorithm for agile satellite-based acquisition operations

    Science.gov (United States)

    Bunkheila, Federico; Ortore, Emiliano; Circi, Christian

    2016-06-01

    Taking advantage of the high manoeuvrability and the accurate pointing of the so-called agile satellites, an algorithm which allows efficient management of the operations concerning optical acquisitions is described. Fundamentally, this algorithm can be subdivided into two parts: in the first one the algorithm operates a geometric classification of the areas of interest and a partitioning of these areas into stripes which develop along the optimal scan directions; in the second one it computes the succession of the time windows in which the acquisition operations of the areas of interest are feasible, taking into consideration the potential restrictions associated with these operations and with the geometric and stereoscopic constraints. The results and the performances of the proposed algorithm have been determined and discussed considering the case of the Periodic Sun-Synchronous Orbits.

  19. SILEX ground segment control facilities and flight operations

    Science.gov (United States)

    Demelenne, Benoit; Tolker-Nielsen, Toni; Guillen, Jean-Claude

    1999-04-01

    The European Space Agency is going to conduct an inter orbit link experiment which will connect a low Earth orbiting satellite and a Geostationary satellite via optical terminals. This experiment has been called SILEX (Semiconductor Inter satellite Link Experiment). Two payloads have been built. One called PASTEL (PASsager de TELecommunication) has been embarked on the French Earth observation satellite SPOT4 which has been launched successfully in March 1998. The future European experimental data relay satellite ARTEMIS (Advanced Relay and TEchnology MISsion), which will route the data to ground, will carry the OPALE terminal (Optical Payload Experiment). The European Space Agency is responsible for the operation of both terminals. Due to the complexity and experimental character of this new optical technology, the development, preparation and validation of the ground segment control facilities required a long series of technical and operational qualification tests. This paper is presenting the operations concept and the early results of the PASTEL in orbit operations.

  20. Satellite Anomalies: Benefits of a Centralized Anomaly Database and Methods for Securely Sharing Information Among Satellite Operators

    Science.gov (United States)

    2014-01-01

    a hardware defect, accidental interference, purposeful attack , or a space weather event. However, there are obstacles that inhibit satellite owners...operator error in commanding the satellite, electromagnetic interference (“jamming”— be it unintentional or intentional), and targeted attack by an...Russian Cosmos 2251 satellite accidentally collided with the operational Iridium -33 spacecraft at a LEO altitude of 790 km (e.g., Iannotta and Malik

  1. Satellite Laser Ranging Photon-Budget Calculations for a Single Satellite Cornercube Retroreflector: Attitude Control Tolerance

    Science.gov (United States)

    2015-11-01

    UNCLASSIFIED Satellite Laser Ranging Photon-Budget Calculations for a Single Satellite Cornercube Retroreflector: Attitude Control Tolerance Philip C...the SLR station, and the direction of the satellite from the SLR station. The required attitude control tolerance is to within 17◦ of the optimal... attitude control strategy determined in the present work. A pre-launch measurement of the re- flectance (diffraction) pattern of each retroreflector is

  2. Observer-based Satellite Attitude Control and Simulation Researches

    Institute of Scientific and Technical Information of China (English)

    王子才; 马克茂

    2002-01-01

    Observer design method is applied to the realization of satellite attitude control law baaed on simplified control model. Exact mathematical model of the satellite attitude control system is also constructed, together with the observer-based control law, to conduct simulation research. The simulation results justify the effectiveness andfeasibility of the observer-based control method.

  3. PID Controller with Operational Amplifier

    Directory of Open Access Journals (Sweden)

    Cristian Paul Chioncel

    2009-01-01

    Full Text Available The paper presents a PID controller made with LM741 operational amplifier that implement the PID controllers laws and allow for a widerange of applications of in the field of automatic control of technicalprocesses and systems.

  4. 78 FR 78257 - Verification of Statements of Account Submitted by Cable Operators and Satellite Carriers

    Science.gov (United States)

    2013-12-26

    ... Satellite Carriers AGENCY: U.S. Copyright Office, Library of Congress. ACTION: Interim rule. SUMMARY: The U... Satellite Television Extension and Localism Act of 2010 (``STELA''). Cable operators and satellite carriers... regulations to allow copyright owners to audit the SOAs and royalty fees that cable operators and...

  5. 77 FR 55783 - Verification of Statements of Account Submitted by Cable Operators and Satellite Carriers

    Science.gov (United States)

    2012-09-11

    ... Satellite Carriers AGENCY: Copyright Office, Library of Congress. ACTION: Notice of proposed rulemaking... Account and royalty payments that are deposited with the Office by cable operators and satellite carriers... to audit the Statements of Account and royalty fees that cable operators and satellite...

  6. Testing a satellite automatic nutation control system. [on synchronous meteorological satellite

    Science.gov (United States)

    Hrasiar, J. A.

    1974-01-01

    Testing of a particular nutation control system for the synchronous meteorological satellite (SMS) is described. The test method and principles are applicable to nutation angle control for other satellites with similar requirements. During its ascent to synchronous orbit, a spacecraft like the SMS spins about its minimum-moment-of-inertia axis. An uncontrolled spacecraft in this state is unstable because torques due to fuel motion increase the nutation angle. However, the SMS is equipped with an automatic nutation control (ANC) system which will keep the nutation angle close to zero. Because correct operation of this system is critical to mission success, it was tested on an air-bearing table. The ANC system was mounted on the three-axis air-bearing table which was scaled to the SMS and equipped with appropriate sensors and thrusters. The table was spun up in an altitude chamber and nutation induced so that table motion simulated spacecraft motion. The ANC system was used to reduce the nutation angle. This dynamic test of the ANC system met all its objectives and provided confidence that the ANC system will control the SMS nutation angle.

  7. Flexible Satellite Attitude Control via Adaptive Fuzzy Linearization

    Institute of Scientific and Technical Information of China (English)

    GUAN Ping; LIU Xiang-dong; CHEN Jia-bin; LIU Xiao-he

    2005-01-01

    The adaptive fuzzy control is combined with input-output linearization control to constitute the hybrid controller. The control method is then applied to the attitude maneuver control of the flexible satellite.The basic control structure is given. The rules of the controller parameter selection, which guarantee the attitude stabilization of the satellite with parameter uncertainties, have been analyzed. Simulation results show that the precise attitude control is accomplished in spite of the uncertainty in the system.

  8. Optimal Release Control of Companion Satellite System Using Electromagnetic Forces

    Institute of Scientific and Technical Information of China (English)

    Zengwen Xu,Peng Shi; Yushan Zhao∗

    2015-01-01

    Electromagnetic forces generated by the inter⁃action of component satellites can be used to release companion satellites. Optimal release trajectories for companion satellite system using inter⁃electromagnetic forces were investigated. Firstly, nonlinear relative motion dynamic equations of a two⁃craft electromagnetic companion satellite system were derived in spatial polar coordinates. Then principles of electromagnetic satellite formation flying were introduced. Secondly, the characteristics of the electromagnetic companion satellites release were analyzed and optimal release trajectories of companion satellites using electromagnetic forces were obtained using Gauss pseudospectral method. Three performance criteria were chosen as minimum time, minimum acceleration of the separation distance and minimum control acceleration. Finally, three release examples including expansion along separation distance, rotation in orbital plane and stable formation reconfiguration were given to demonstrate the feasibility of this method. Results indicated that the release trajectories can converge to optimal solutions effectively and the concept of release companion satellites using electromagnetic forces is practicable.

  9. Operational facilities of remote control software of ranging measurement equipment

    Science.gov (United States)

    Becceneri, Jose Carlos

    The basic purpose of this paper is to document, in this symposium, the work performed for the construction of Ranging Management Software (RAN), which is one of the functions of the Satellite Control System (SICS) software developed by Instituto Nacional de Pesquisas Espaciais (INPE) to control the Brazilian satellites of MECB (Brazilian Complete Space Mission). This paper shows the RAN basic architecture as well as a set of functions which facilitates both the operation and the ranging system test.

  10. An Overview Of Operational Satellites Built By China: Communications Satellites (Part1)

    Institute of Scientific and Technical Information of China (English)

    Guang Bo

    2008-01-01

    @@ Communications satellite technology has seen great advances since Decemher 1958 when the Americans launched the first experimental communications satellite.Currently, satellite communications account for over 80 percent of the intercontinental communications traffic and 100 percent of international live TV broadcast, while taking part in domestic and regional services. Moreover, the satellite communication service is showing a favorable continuous growth tendency.

  11. Geostationary Operational Environmental Satellite (GOES) Gyro Temperature Model

    Science.gov (United States)

    Rowe, J. N.; Noonan, C. H.; Garrick, J.

    1996-01-01

    The geostationary Operational Environmental Satellite (GOES) 1/M series of spacecraft are geostationary weather satellites that use the latest in weather imaging technology. The inertial reference unit package onboard consists of three gyroscopes measuring angular velocity along each of the spacecraft's body axes. This digital integrating rate assembly (DIRA) is calibrated and used to maintain spacecraft attitude during orbital delta-V maneuvers. During the early orbit support of GOES-8 (April 1994), the gyro drift rate biases exhibited a large dependency on gyro temperature. This complicated the calibration and introduced errors into the attitude during delta-V maneuvers. Following GOES-8, a model of the DIRA temperature and drift rate bias variation was developed for GOES-9 (May 1995). This model was used to project a value of the DIRA bias to use during the orbital delta-V maneuvers based on the bias change observed as the DIRA warmed up during the calibration. The model also optimizes the yaw reorientation necessary to achieve the correct delta-V pointing attitude. As a result, a higher accuracy was achieved on GOES-9 leading to more efficient delta-V maneuvers and a propellant savings. This paper summarizes the: Data observed on GOES-8 and the complications it caused in calibration; DIRA temperature/drift rate model; Application and results of the model on GOES-9 support.

  12. Differential spacecraft charging on the geostationary operational environmental satellites

    Science.gov (United States)

    Farthing, W. H.; Brown, J. P.; Bryant, W. C.

    1982-01-01

    Subsystems aboard the Geostationary Operational Environmental Satellites 4 and 5 showed instances of anomalous changes in state corresponding to false commands. Evidence linking the anomalous changes to geomagnetic activity, and presumably static discharges generated by spacecraft differential charging induced by substorm particle injection events is presented. The anomalies are shown to be correlated with individual substorms as monitored by stations of the North American Magnetometer Chain. The relative frequency of the anomalies is shown to be a function of geomagnetic activity. Finally a least squares fit to the time delay between substorm initiation and spacecraft anomaly as a function of spacecraft local time is shown to be consistent with injected electron populations with energy in the range 10 keV to 15 keV, in agreement with present understanding of the spacecraft charging mechanism. The spacecraft elements responsible for the differential charging were not satisfactorily identified. That question is currently under investigation.

  13. Umatilla Hatchery Satellite Facilities Operation and Maintenance; 1996 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Rowan, Gerald D.

    1997-06-01

    The Confederated Tribes of the Umatilla Indian Reservation (CTUIR) and Oregon Department of Fish and Wildlife (ODFW) are cooperating in a joint effort to enhance steelhead and re-establish salmon runs in the Umatilla River Basin. As an integral part of this program, Bonifer Pond, Minthorn Springs, Imeques C-mem-ini-kem and Thornhollow satellite facilities are operated for acclimation and release of juvenile summer steelhead (Oncorhynchus mykiss), fall and spring chinook salmon (O. tshawytscha) and coho salmon (O. kisutch). Minthorn is also used for holding and spawning adult summer steelhead and Three Mile Dam is used for holding and spawning adult fall chinook and coho salmon. Bonifer, Minthorn, Imeques and Thornhollow facilities are operated for acclimation and release of juvenile salmon and summer steelhead. The main goal of acclimation is to reduce stress from trucking prior to release and improve imprinting of juvenile salmonids in the Umatilla River Basin. Juveniles are transported to the acclimation facilities primarily from Umatilla and Bonneville Hatcheries. This report details activities associated with operation and maintenance of the Bonifer, Minthorn, Imeques, Thornhollow and Three Mile Dam facilities in 1996.

  14. Bilateral Control - Operational enhancements

    OpenAIRE

    Altınışık, Ahmet; Altinisik, Ahmet

    2006-01-01

    A succinct definition of the word bilateral is having two sides [1]. In robotics the term bilateral control is used to define the specific interaction of two systems by means of position and/or force. Bilateral systems are composed of two sides named master and slave side. The aim of such an arrangement is such that position command dictated by master side is followed by a slave side, and at the same time the force sensation of the remote environment experienced by slave is transferred to the...

  15. Interface control procedures for university satellite programmes

    NARCIS (Netherlands)

    Perez Lebbink, L.; Hamann, R.J.; Bouwmeester, J.; Brouwer, G.F.

    2009-01-01

    Now that more and more universities have joined the CubeSat community and have their own satellite in Earth orbit, it is expected that the planned successors will be of higher complexity. These successors within a university satellite programme will often house more technically ad-vanced subsystems

  16. Interface control procedures for university satellite programmes

    NARCIS (Netherlands)

    Perez Lebbink, L.; Hamann, R.J.; Bouwmeester, J.; Brouwer, G.F.

    2009-01-01

    Now that more and more universities have joined the CubeSat community and have their own satellite in Earth orbit, it is expected that the planned successors will be of higher complexity. These successors within a university satellite programme will often house more technically ad-vanced subsystems

  17. 47 CFR 25.146 - Licensing and operating authorization provisions for the non-geostationary satellite orbit fixed...

    Science.gov (United States)

    2010-10-01

    ... provisions for the non-geostationary satellite orbit fixed-satellite service (NGSO FSS) in the bands 10.7 GHz... Licensing and operating authorization provisions for the non-geostationary satellite orbit fixed-satellite... submitted for the proposed non-geostationary satellite orbit fixed-satellite service (NGSO FSS) system...

  18. Implementation and Test of the Automatic Flight Dynamics Operations for Geostationary Satellite Mission

    Science.gov (United States)

    Park, Sangwook; Lee, Young-Ran; Hwang, Yoola; Javier Santiago Noguero Galilea

    2009-12-01

    This paper describes the Flight Dynamics Automation (FDA) system for COMS Flight Dynamics System (FDS) and its test result in terms of the performance of the automation jobs. FDA controls the flight dynamics functions such as orbit determination, orbit prediction, event prediction, and fuel accounting. The designed FDA is independent from the specific characteristics which are defined by spacecraft manufacturer or specific satellite missions. Therefore, FDA could easily links its autonomous job control functions to any satellite mission control system with some interface modification. By adding autonomous system along with flight dynamics system, it decreases the operator’s tedious and repeated jobs but increase the usability and reliability of the system. Therefore, FDA is used to improve the completeness of whole mission control system’s quality. The FDA is applied to the real flight dynamics system of a geostationary satellite, COMS and the experimental test is performed. The experimental result shows the stability and reliability of the mission control operations through the automatic job control.

  19. High Precision Control of Ship-Mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Mohsen, Soltani; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2007-01-01

    The telecommunication on a modern merchandise ship is maintained by means of satellite communication. The task of the tracking system is to position the on-board antenna toward a chosen satellite. The control system is capable of rejecting the external disturbances which affect on the under......-actuated antenna and ensures that it remains locked on the satellite. In this paper, a nonlinear internal model controller (NIMC), which achieves asymptotic tracking for the nonlinear antenna system with nonlinear exogenous dynamics, is proposed. Computer simulations as well as practical tests verify...... the effectiveness of this method to cope with the external disturbances that are imposed to the satellite tracking antenna (STA)....

  20. High Precision Control of Ship-Mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Mohsen, Soltani; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2007-01-01

    The telecommunication on a modern merchandise ship is maintained by means of satellite communication. The task of the tracking system is to position the on-board antenna toward a chosen satellite. The control system is capable of rejecting the external disturbances which affect on the under......-actuated antenna and ensures that it remains locked on the satellite. In this paper, a nonlinear internal model controller (NIMC), which achieves asymptotic tracking for the nonlinear antenna system with nonlinear exogenous dynamics, is proposed. Computer simulations as well as practical tests verify...... the effectiveness of this method to cope with the external disturbances that are imposed to the satellite tracking antenna (STA)....

  1. 77 FR 60333 - Verification of Statements of Account Submitted by Cable Operators and Satellite Carriers

    Science.gov (United States)

    2012-10-03

    ... Satellite Carriers AGENCY: Copyright Office, Library of Congress. ACTION: Notice of proposed rulemaking... satellite carriers. DATES: Reply comments on the proposed rule published at 77 FR 35643, June 14, 2012, must... of Account and royalty fees that cable operators and satellite carriers deposit with the...

  2. 77 FR 77001 - Comprehensive Review of Licensing and Operating Rules for Satellite Services

    Science.gov (United States)

    2012-12-31

    ... COMMISSION 47 CFR Part 25 Comprehensive Review of Licensing and Operating Rules for Satellite Services AGENCY... this document. FOR FURTHER INFORMATION CONTACT: William Bell (202) 418-0741, Satellite Division... Satellite Services, adopted and released on December 19, 2012. The full text of this document is...

  3. Satellite Attitude Control System Design considering the Fuel Slosh Dynamics

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Gadelha de Souza

    2014-01-01

    Full Text Available The design of the satellite attitude control system (ACS becomes more complex when the satellite structure has different type of components like, flexible solar panels, antennas, mechanical manipulators, and tanks with fuel. A crucial interaction can occur between the fuel slosh motion and the satellite rigid motion during translational and/or rotational manoeuvre since these interactions can change the satellite centre of mass position damaging the ACS pointing accuracy. Although, a well-designed controller can suppress such disturbances quickly, the controller error pointing may be limited by the minimum time necessary to suppress such disturbances thus affecting the satellite attitude acquisition. As a result, the design of the satellite controller needs to explore the limits between the conflicting requirements of performance and robustness. This paper investigates the effects of the interaction between the liquid motion (slosh and the satellite dynamics in order to predict what the damage to the controller performance and robustness is. The fuel slosh dynamics is modelled by a pendulum which parameters are identified using the Kalman filter technique. This information is used to design the satellite controller by the linear quadratic regulator (LQR and linear quadratic Gaussian (LQG methods to perform a planar manoeuvre assuming thrusters are actuators.

  4. Remote Operations Control Center (ROCC)

    Science.gov (United States)

    1997-01-01

    Students at Rensselaer Polytechnic Institute (RPI) in Troy, NY, monitor the progress of the Isothermal Dendritic Growth Experiment (IDGE) during the U.S. Microgravity Payload-4 (USMP-4) mission (STS-87, Nov. 19 - Dec. 5, 1997). Remote Operation Control Center (ROCC) like this one will become more common during operations with International Space Station. IDGE, flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. Photo credit: Renssenlaer Polythnic Institute (RPI)

  5. A Robust Controller Structure for Pico-Satellite Applications

    DEFF Research Database (Denmark)

    Kragelund, Martin Nygaard; Green, Martin; Kristensen, Mads

    This paper describes the development of a robust controller structure for use in pico-satellite missions. The structure relies on unknown disturbance estimation and use of robust control theory to implement a system that is robust to both unmodeled disturbances and parameter uncertainties. As one...... possible application, a satellite mission with the purpose of monitoring shipping routes for oil spills has been considered. However, it is the aim of the control structure to be widely applicable and adaptable for a vide variety of pico-satellite missions. The robust control structure has been evaluated...

  6. GHRSST Level 2P Eastern Pacific Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-11 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

  7. GHRSST Level 2P West Atlantic Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-12 satellite (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

  8. Human factors dimensions in the evolution of increasingly automated control rooms for near-earth satellites

    Science.gov (United States)

    Mitchell, C. M.

    1982-01-01

    The NASA-Goddard Space Flight Center is responsible for the control and ground support for all of NASA's unmanned near-earth satellites. Traditionally, each satellite had its own dedicated mission operations room. In the mid-seventies, an integration of some of these dedicated facilities was begun with the primary objective to reduce costs. In this connection, the Multi-Satellite Operations Control Center (MSOCC) was designed. MSOCC represents currently a labor intensive operation. Recently, Goddard has become increasingly aware of human factors and human-machine interface issues. A summary is provided of some of the attempts to apply human factors considerations in the design of command and control environments. Current and future activities with respect to human factors and systems design are discussed, giving attention to the allocation of tasks between human and computer, and the interface for the human-computer dialogue.

  9. Human factors dimensions in the evolution of increasingly automated control rooms for near-earth satellites

    Science.gov (United States)

    Mitchell, C. M.

    1982-01-01

    The NASA-Goddard Space Flight Center is responsible for the control and ground support for all of NASA's unmanned near-earth satellites. Traditionally, each satellite had its own dedicated mission operations room. In the mid-seventies, an integration of some of these dedicated facilities was begun with the primary objective to reduce costs. In this connection, the Multi-Satellite Operations Control Center (MSOCC) was designed. MSOCC represents currently a labor intensive operation. Recently, Goddard has become increasingly aware of human factors and human-machine interface issues. A summary is provided of some of the attempts to apply human factors considerations in the design of command and control environments. Current and future activities with respect to human factors and systems design are discussed, giving attention to the allocation of tasks between human and computer, and the interface for the human-computer dialogue.

  10. Economic benefits of the Space Station to commercial communication satellite operators

    Science.gov (United States)

    Price, Kent M.; Dixson, John E.; Weyandt, Charles J.

    1987-01-01

    The economic and financial aspects of newly defined space-based activities, procedures, and operations (APOs) and associated satellite system designs are presented that have the potential to improve economic performance of future geostationary communications satellites. Launch insurance, launch costs, and the economics of APOs are examined. Retrieval missions and various Space Station scenarios are addressed. The potential benefits of the new APOs to the commercial communications satellite system operator are quantified.

  11. The EMC impact of SPS operations on low Earth orbit satellites

    Science.gov (United States)

    Grant, W. B.; Morrison, E. L., Jr.; Davis, K. C.

    1980-01-01

    The susceptibility of various operational and planned low Earth orbit satellites to solar power satellite (SPS) operations was examined. Functional degradation for the electronic systems on LANDSAT, the global positioning system, and the space telescope is described in relation to the amplitude of the SPS illumination components. Analyses include the modes of coupling to devices and subsystems, and performance effects in relation to satellite mission.

  12. NASA Operational Simulator for Small Satellites (NOS3)

    Science.gov (United States)

    Zemerick, Scott

    2015-01-01

    The Simulation-to-Flight 1 (STF-1) CubeSat mission aims to demonstrate how legacy simulation technologies may be adapted for flexible and effective use on missions using the CubeSat platform. These technologies, named NASA Operational Simulator (NOS), have demonstrated significant value on several missions such as James Webb Space Telescope, Global Precipitation Measurement, Juno, and Deep Space Climate Observatory in the areas of software development, mission operationstraining, verification and validation (VV), test procedure development and software systems check-out. STF-1 will demonstrate a highly portable simulation and test platform that allows seamless transition of mission development artifacts to flight products. This environment will decrease development time of future CubeSat missions by lessening the dependency on hardware resources. In addition, through a partnership between NASA GSFC, the West Virginia Space Grant Consortium and West Virginia University, the STF-1 CubeSat will hosts payloads for three secondary objectives that aim to advance engineering and physical-science research in the areas of navigation systems of small satellites, provide useful data for understanding magnetosphere-ionosphere coupling and space weather, and verify the performance and durability of III-V Nitride-based materials.

  13. Operational Testing of Satellite based Hydrological Model (SHM)

    Science.gov (United States)

    Gaur, Srishti; Paul, Pranesh Kumar; Singh, Rajendra; Mishra, Ashok; Gupta, Praveen Kumar; Singh, Raghavendra P.

    2017-04-01

    Incorporation of the concept of transposability in model testing is one of the prominent ways to check the credibility of a hydrological model. Successful testing ensures ability of hydrological models to deal with changing conditions, along with its extrapolation capacity. For a newly developed model, a number of contradictions arises regarding its applicability, therefore testing of credibility of model is essential to proficiently assess its strength and limitations. This concept emphasizes to perform 'Hierarchical Operational Testing' of Satellite based Hydrological Model (SHM), a newly developed surface water-groundwater coupled model, under PRACRITI-2 program initiated by Space Application Centre (SAC), Ahmedabad. SHM aims at sustainable water resources management using remote sensing data from Indian satellites. It consists of grid cells of 5km x 5km resolution and comprises of five modules namely: Surface Water (SW), Forest (F), Snow (S), Groundwater (GW) and Routing (ROU). SW module (functions in the grid cells with land cover other than forest and snow) deals with estimation of surface runoff, soil moisture and evapotranspiration by using NRCS-CN method, water balance and Hragreaves method, respectively. The hydrology of F module is dependent entirely on sub-surface processes and water balance is calculated based on it. GW module generates baseflow (depending on water table variation with the level of water in streams) using Boussinesq equation. ROU module is grounded on a cell-to-cell routing technique based on the principle of Time Variant Spatially Distributed Direct Runoff Hydrograph (SDDH) to route the generated runoff and baseflow by different modules up to the outlet. For this study Subarnarekha river basin, flood prone zone of eastern India, has been chosen for hierarchical operational testing scheme which includes tests under stationary as well as transitory conditions. For this the basin has been divided into three sub-basins using three flow

  14. Operational Control of Internal Transport

    NARCIS (Netherlands)

    J.R. van der Meer (Robert)

    2000-01-01

    textabstractOperational Control of Internal Transport considers the control of guided vehicles in vehicle-based internal transport systems found in facilities such as warehouses, production plants, distribution centers and transshipment terminals. The author's interest of research having direct use

  15. IT Strategic and Operational Controls

    CERN Document Server

    Kyriazoglou, J

    2010-01-01

    This book provides a comprehensive guide to implementing an integrated and flexible set of IT controls in a systematic way. It can help organisations to formulate a complete culture for all areas which must be supervised and controlled; allowing them to simultaneously ensure a secure, high standard whilst striving to obtain the strategic and operational goals of the company.

  16. Integrated power and attitude control of a rigid satellite with onboard magnetic bearing suspended rigid flywheels

    Science.gov (United States)

    Kim, Yeonkyu

    2003-10-01

    A system of differential equations governing the translational and rotational motion of a system model consisting of a rigid satellite and multiple MB suspended rigid flywheels in general configuration is developed. Flywheel modules are contained in a housing rigidly mounted on the satellite and floated by an active MB suspension system, therefore each flywheel module has six degrees of freedom (DOF) as well as the satellite module. Equations of motion for the satellite and flywheels are naturally coupled and the satellite rotational motion and translational motion are coupled. A nonlinear state feedback tracking control law, which is globally asymptotically stable, is developed following a Lyapunov stability theory for integrated power and attitude control using the MB suspended flywheels. The stability, robustness, and tracking and disturbance rejection performance of the present control law with respect to initial attitude error, system modeling error, an imbalance disturbance, is demonstrated by case studies. The satellite departure motion equation derived from the definition of the angular velocity error and the system dynamics equations is presented. Application study of existing power tracking algorithm with this control law shows perfect power tracking for both power charging from and power delivery to the satellite operations and the power tracking can be performed simultaneously with and independent of the attitude control function.

  17. Sliding Mode Attitude Control for Magnetic Actuated Satellite

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1998-01-01

    Magnetic torquing is attractive as a control principle on small satellites. The actuation principle is to use the interaction between the earth's magnetic field and magnetic field generated by a coil set in the satellite. This control principle is inherently nonlinear, and difficult to use becaus...... the spacecraft attitude using only magnetic torquing is realized in the form of the sliding mode control. A three dimensional sliding manifold is proposed, and it is shown that the satellite motion on the sliding manifold is asymptotically stable......Magnetic torquing is attractive as a control principle on small satellites. The actuation principle is to use the interaction between the earth's magnetic field and magnetic field generated by a coil set in the satellite. This control principle is inherently nonlinear, and difficult to use because...... control torques can only be generated perpendicular to the local geomagnetic field vector. This has been a serious obstacle for using magnetorquer based control for three-axis attitude control. This paper deals with three-axis stabilization of a low earth orbit satellite. The problem of controlling...

  18. Guidance and Control System for a Satellite Constellation

    Science.gov (United States)

    Bryson, Jonathan Lamar; Cox, James; Mays, Paul Richard; Neidhoefer, James Christian; Ephrain, Richard

    2010-01-01

    A distributed guidance and control algorithm was developed for a constellation of satellites. The system repositions satellites as required, regulates satellites to desired orbits, and prevents collisions. 1. Optimal methods are used to compute nominal transfers from orbit to orbit. 2. Satellites are regulated to maintain the desired orbits once the transfers are complete. 3. A simulator is used to predict potential collisions or near-misses. 4. Each satellite computes perturbations to its controls so as to increase any unacceptable distances of nearest approach to other objects. a. The avoidance problem is recast in a distributed and locally-linear form to arrive at a tractable solution. b. Plant matrix values are approximated via simulation at each time step. c. The Linear Quadratic Gaussian (LQG) method is used to compute perturbations to the controls that will result in increased miss distances. 5. Once all danger is passed, the satellites return to their original orbits, all the while avoiding each other as above. 6. The delta-Vs are reasonable. The controller begins maneuvers as soon as practical to minimize delta-V. 7. Despite the inclusion of trajectory simulations within the control loop, the algorithm is sufficiently fast for available satellite computer hardware. 8. The required measurement accuracies are within the capabilities of modern inertial measurement devices and modern positioning devices.

  19. Orbit control of a stratospheric satellite with parameter uncertainties

    Science.gov (United States)

    Xu, Ming; Huo, Wei

    2016-12-01

    When a stratospheric satellite travels by prevailing winds in the stratosphere, its cross-track displacement needs to be controlled to keep a constant latitude orbital flight. To design the orbit control system, a 6 degree-of-freedom (DOF) model of the satellite is established based on the second Lagrangian formulation, it is proven that the input/output feedback linearization theory cannot be directly implemented for the orbit control with this model, thus three subsystem models are deduced from the 6-DOF model to develop a sequential nonlinear control strategy. The control strategy includes an adaptive controller for the balloon-tether subsystem with uncertain balloon parameters, a PD controller based on feedback linearization for the tether-sail subsystem, and a sliding mode controller for the sail-rudder subsystem with uncertain sail parameters. Simulation studies demonstrate that the proposed control strategy is robust to uncertainties and satisfies high precision requirements for the orbit flight of the satellite.

  20. Automatic charge control system for satellites

    Science.gov (United States)

    Shuman, B. M.; Cohen, H. A.

    1985-01-01

    The SCATHA and the ATS-5 and 6 spacecraft provided insights to the problem of spacecraft charging at geosychronous altitudes. Reduction of the levels of both absolute and differential charging was indicated, by the emission of low energy neutral plasma. It is appropriate to complete the transition from experimental results to the development of a system that will sense the state-of-charge of a spacecraft, and, when a predetermined threshold is reached, will respond automatically to reduce it. A development program was initiated utilizing sensors comparable to the proton electrostatic analyzer, the surface potential monitor, and the transient pulse monitor that flew in SCATHA, and combine these outputs through a microprocessor controller to operate a rapid-start, low energy plasma source.

  1. SCAILET: An intelligent assistant for satellite ground terminal operations

    Science.gov (United States)

    Shahidi, A. K.; Crapo, J. A.; Schlegelmilch, R. F.; Reinhart, R. C.; Petrik, E. J.; Walters, J. L.; Jones, R. E.

    1993-05-01

    NASA Lewis Research Center has applied artificial intelligence to an advanced ground terminal. This software application is being deployed as an experimenter interface to the link evaluation terminal (LET) and was named Space Communication Artificial Intelligence for the Link Evaluation Terminal (SCAILET). The high-burst-rate (HBR) LET provides 30-GHz-transmitting and 20-GHz-receiving, 220-Mbps capability for wide band communications technology experiments with the Advanced Communication Technology Satellite (ACTS). The HBR-LET terminal consists of seven major subsystems. A minicomputer controls and monitors these subsystems through an IEEE-488 or RS-232 protocol interface. Programming scripts (test procedures defined by design engineers) configure the HBR-LET and permit data acquisition. However, the scripts are difficult to use, require a steep learning curve, are cryptic, and are hard to maintain. This discourages experimenters from utilizing the full capabilities of the HBR-LET system. An intelligent assistant module was developed as part of the SCAILET software. The intelligent assistant addresses critical experimenter needs by solving and resolving problems that are encountered during the configuring of the HBR-LET system. The intelligent assistant is a graphical user interface with an expert system running in the background. In order to further assist and familiarize an experimenter, an on-line hypertext documentation module was developed and included in the SCAILET software.

  2. Power generation, operation, and control

    CERN Document Server

    Wood, Allen J

    2012-01-01

    A comprehensive text on the operation and control of power generation and transmission systems In the ten years since Allen J. Wood and Bruce F. Wollenberg presented their comprehensive introduction to the engineering and economic factors involved in operating and controlling power generation systems in electric utilities, the electric power industry has undergone unprecedented change. Deregulation, open access to transmission systems, and the birth of independent power producers have altered the structure of the industry, while technological advances have created a host of new opportunities

  3. Control of satellite clusters in elliptic orbit with limited communication.

    Science.gov (United States)

    Chichka, David F; Belanger, Gene; Speyer, Jason L

    2004-05-01

    The cooperative control of satellite clusters in elliptical, low-Earth orbit is studied, with the goal of minimizing the necessary information passed among the individual satellites in the cluster. We investigate two possible control paradigms in this paper. The system is described using linearized equations of motion, allowing it to be expressed as a time-varying linear system. The control objective is to attain a required formation at a specified point along the orbit. A decentralized controller is used, in which each satellite maintains a local estimate of the overall state of the cluster. These estimates, along with any control information, are shared after any satellite executes a control action. The second paradigm is an extension of the first, in which state estimates are never shared, and only the control information is passed. In each case, less information being passed results in a higher computational burden on each satellite. Simulation results show cyclic errors, likely induced by higher-order terms in eccentricity and inclinations. The controller that shares state estimates performs much better than the controller that passes only control information.

  4. An Overview Of Operational Satellites Built By China:Communications Satellites (Part 2)

    Institute of Scientific and Technical Information of China (English)

    Zong He

    2009-01-01

    @@ INNOVATIVE GENERATION: THE DFH-4 PLATFORM AND SATELLITES The DFH-4 platform is the third generation of China-built large geostationary satellite platform with large output power,payload capacity and long service lifetime.Its overall performance ranks with other international advanced satellite platforms.This platform can be used for many services such as high capacity broadcast communication,direct TV broadcasting,digital audio broadcasting and broadband multimedia,which are badly needed for national economic construction and markets both at home and abroad.The platform also has effective technologies that can ensure the security of information transmission.

  5. The geo-control system for station keeping and colocation of geostationary satellites

    Science.gov (United States)

    Montenbruck, O.; Eckstein, M. C.; Gonner, J.

    1993-01-01

    GeoControl is a compact but powerful and accurate software system for station keeping of single and colocated satellites, which has been developed at the German Space Operations Center. It includes four core modules for orbit determination (including maneuver estimation), maneuver planning, monitoring of proximities between colocated satellites, and interference and event prediction. A simple database containing state vector and maneuver information at selected epochs is maintained as a central interface between the modules. A menu driven shell utilizing form screens for data input serves as the central user interface. The software is written in Ada and FORTRAN and may be used on VAX workstations or mainframes under the VMS operating system.

  6. A Constraint Based Approach for Building Operationally Responsive Satellites

    Science.gov (United States)

    2008-09-01

    discipline specific software codes into a common environment. LLB team also uses MATLAB R© to integrate CAD tools such as Catia , Pro/Engineer with FE...satellite configuration through a Catia CAD tool. The LLB approach is similar to the approach discussed in this research because it provides a method

  7. Accuracy of surface heat fluxes from observations of operational satellites

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Sugimori, Y.

    with uncertainties for same flux values resulting from climatological ship observations. For net satellite derived heat flux varying from 0 to 300 w/m sup(2) the uncertainties were found to be of the order of 50-90 w/m sup(2). For the same range of flux values...

  8. TELE-X and its role in a future operational Nordic satellite system

    Science.gov (United States)

    Anderson, Lars

    In the middle of 1987 it is planned to launch TELE-X, the first Nordic telecommunications satellite. The Swedish-Norwegian company NOTELSAT (Nordic Telecommunications Satellite Corporation) will be responsible for the operation of the TELE-X system. Via the experimental TELE-X satellite the Nordic countries will get access to direct broadcasting of two TV-programs and at least four digital sound programs in stereo by use of two transponders in the 12.2 to 12.5 GHz band. The programs are planned to be composed of nationally produced programs in Norway. Sweden and Finland. By means of distributing these programs via satellite they will reach up to 4 times as many viewers and listernes as presently in the terrestrial national systems. The basic motivations for exchanging programs are to strengthen the cultural ties between the Nordic countries and to give the individuals more freedom in the choice of programs. Another goal is to give the public a better sound and picture quality than can be achieved today. These quality improvements shall be met by using small receiver parabolas of less than 1 m in diameter. Contributing to the improved quality is the choice of the C-MAC (Multiplexed Analoque Components) modulation system. TELE-X is a multipurpose satellite which besides the two TV-transponders will have two transponders for data/video communication in the frequency band 12.5 to 12.75 GHz. The choice of system for data and video is based on the philosophy of thin-route traffic between small and low cost earth stations (1.8 to 2.5 m) placed directly at the subscribers premises. The system includes an advanced Data/Video Control Station which automatically connects the traffic stations with standarized transmission speeds up to 2 Mbps. The system which is based on the SCPC/DAMA method can be expanded up to 5000 traffic stations. Numerous data/video applications will be investigated in the initial experimental phase of the project which also will be used for market

  9. Satellite Dynamic Damping via Active Force Control Augmentation

    Science.gov (United States)

    Varatharajoo, Renuganth

    2012-07-01

    An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for a satellite active dynamic damping towards a full attitude control. The AFC method has been established to facilitate a robust motion control of dynamical systems in the presence of disturbances, parametric uncertainties and changes that are commonly prevalent in the real-world environment. The usefulness of the method can be extended by introducing intelligent mechanisms to approximate the mass or inertia matrix of the dynamic system to trigger the compensation effect of the controller. AFC is a technique that relies on the appropriate estimation of the inertial or mass parameters of the dynamic system and the measurements of the acceleration and force signals induced by the system if practical implementation is ever considered. In AFC, it is shown that the system subjected to a number of disturbances remains stable and robust via the compensating action of the control strategy. We demonstrate that it is possible to design a spacecraft attitude feedback controller that will ensure the system dynamics set point remains unchanged even in the presence of the disturbances provided that the actual disturbances can be modeled effectively. In order to further facilitate this analysis, a combined energy and attitude control system (CEACS) is proposed as a model satellite attitude control actuator. All the governing equations are established and the proposed satellite attitude control architecture is made amenable to numerical treatments. The results show that the PD-AFC attitude damping performances are superiorly better than that of the solely PD type. It is also shown that the tunings of the AFC system gains are crucial to ensure a better attitude damping performance and this process is mandatory for AFC systems. Finally, the results demonstrate an important satellite dynamic damping enhancement capability using the AFC

  10. The Integration of Small Satellites in Maritime Interdiction Operations (MIO)

    Science.gov (United States)

    2012-09-01

    BLANK xiii LIST OF ACRONYMS AND ABBREVIATIONS AIS Automatic Identification system BER Bit Error Rate BGAN Broadband Global Area Network bps...was the Broadband Global Area Network ( BGAN ), a global-coverage network that uses three satellites in geostationary orbits and is provided by...NOCTW WR BGAN Mutualink station Target Ship Interdiction Boat Interdiction Boat GPS Tracking Nuc/Rad Sensor Collaboration Station Nuc/Rad Sensor IP

  11. Satellite cascade attitude control via fuzzy PD controller with active force control under momentum dumping

    Science.gov (United States)

    Ismail, Z.; Varatharajoo, R.

    2016-10-01

    In this paper, fuzzy proportional-derivative (PD) controller with active force control (AFC) scheme is studied and employed in the satellite attitude control system equipped with reaction wheels. The momentum dumping is enabled via proportional integral (PI) controller as the system is impractical without momentum dumping control. The attitude controllers are developed together with their governing equations and evaluated through numerical treatment with respect to a reference satellite mission. From the results, it is evident that the three axis attitudes accuracies can be improved up to ±0.001 degree through the fuzzy PD controller with AFC scheme for the attitude control. In addition, the three-axis wheel angular momentums are well maintained during the attitude control tasks.

  12. Umatilla Hatchery Satellite Facilities; Operations and Maintenance, Annual Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    Rowan, Gerald

    2003-05-01

    The Confederated Tribes of the Umatilla Indian Reservation (CTUIR) and Oregon Department of Fish and Wildlife (ODFW) are cooperating in a joint effort to enhance steelhead and re-establish salmon runs in the Umatilla River Basin. As an integral part of this program, Bonifer Pond, Minthorn Springs, Imeques C-mem-ini-kem, Thornhollow and Pendleton satellite facilities are operated for acclimation and release of juvenile summer steelhead (Oncorhynchus mykiss), fall and spring chinook salmon (O. tshawytscha) and coho salmon (O. kisutch). Minthorn is also used for holding and spawning adult summer steelhead and Three Mile Dam and South Fork Walla Walla facilities are used for holding and spawning chinook salmon. In some years, Three Mile Dam may also be used for holding and spawning coho salmon. In the spring of 2002, summer steelhead were acclimated and released at Bonifer Pond (54,917), Minthorn Springs (47,521), and Pendleton (54,366). Yearling coho (1,621,857) were also acclimated and released at Pendleton. Yearling spring chinook salmon (876,121) were acclimated and released at Imeques C-mem-ini-kem. At Thornhollow, 520,564 yearling fall chinook and 307,194 subyearling fall chinook were acclimated. In addition, 104,908 spring chinook were transported to Imeques C-mem-ini-kem in November for release in the spring of 2003. CTUIR and ODFW personnel monitored the progress of outmigration for juvenile releases at the Westland Canal juvenile facility. Nearly all juveniles released in the spring migrated downstream prior to the trap being opened in early July. A total of 100 unmarked and 10 marked summer steelhead were collected for broodstock at Three Mile Dam from September 21, 2001, through April 2, 2002. An estimated 180,955 green eggs were taken from 36 females and were transferred to Umatilla Hatchery for incubation and rearing. A total of 560 adult and 26 jack spring chinook salmon were collected for broodstock at Three Mile Dam from April 22 through June 12, 2002

  13. Reliable Control of Ship-mounted Satellite Tracking Antenna

    DEFF Research Database (Denmark)

    Soltani, Mohsen; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

    2010-01-01

    Motorized antenna is a key element in overseas satellite telecommunication. The control system directs the on-board antenna toward a chosen satellitewhile the high sea waves disturb the antenna. Certain faults (communication system malfunction or signal blocking) cause interruption in the communi......Motorized antenna is a key element in overseas satellite telecommunication. The control system directs the on-board antenna toward a chosen satellitewhile the high sea waves disturb the antenna. Certain faults (communication system malfunction or signal blocking) cause interruption...

  14. Game Theoretic Approach to Post-Docked Satellite Control

    Science.gov (United States)

    Hiramatsu, Takashi; Fitz-Coy, Norman G.

    2007-01-01

    This paper studies the interaction between two satellites after docking. In order to maintain the docked state with uncertainty in the motion of the target vehicle, a game theoretic controller with Stackelberg strategy to minimize the interaction between the satellites is considered. The small perturbation approximation leads to LQ differential game scheme, which is validated to address the docking interactions between a service vehicle and a target vehicle. The open-loop solution are compared with Nash strategy, and it is shown that less control efforts are obtained with Stackelberg strategy.

  15. Sliding mode control of electromagnetic tethered satellite formation

    Science.gov (United States)

    Hallaj, Mohammad Amin Alandi; Assadian, Nima

    2016-08-01

    This paper investigates the control of tethered satellite formation actuated by electromagnetic dipoles and reaction wheels using the robust sliding mode control technique. Generating electromagnetic forces and moments by electric current coils provides an attractive control actuation alternative for tethered satellite system due to the advantages of no propellant consumption and no obligatory rotational motion. Based on a dumbbell model of tethered satellite in which the flexibility and mass of the tether is neglected, the equations of motion in Cartesian coordinate are derived. In this model, the J2 perturbation is taken into account. The far-field and mid-field models of electromagnetic forces and moments of two satellites on each other and the effect of the Earth's magnetic field are presented. A robust sliding mode controller is designed for precise trajectory tracking purposes and to deal with the electromagnetic force and moment uncertainties and external disturbances due to the Earth's gravitational and magnetic fields inaccuracy. Numerical simulation results are presented to validate the effectiveness of the developed controller and its superiority over the linear controller.

  16. 49 CFR 236.777 - Operator, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Operator, control. 236.777 Section 236.777..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.777 Operator, control. An employee assigned to operate the control machine of a traffic control system....

  17. Tilted wheel satellite attitude control with air-bearing table experimental results

    Science.gov (United States)

    Inumoh, Lawrence O.; Forshaw, Jason L.; Horri, Nadjim M.

    2015-12-01

    Gyroscopic actuators for satellite control have attracted significant research interest over the years, but their viability for the control of small satellites has only recently started to become clear. Research on variable speed gyroscopic actuators has long been focused on single gimbal actuators; double gimbal actuators typically operate at constant wheel spin rate and allow tilt angle ranges far larger than the ranges needed to operate most satellite missions. This research examines a tilted wheel, a newly proposed type of inertial actuator that can generate torques in all three principal axes of a rigid satellite using a spinning wheel and a double tilt mechanism. The tilt mechanism tilts the angular momentum vector about two axes providing two degree of freedom control, while variation of the wheel speed provides the third. The equations of motion of the system lead to a singularity-free system during nominal operation avoiding the need for complex steering logic. This paper describes the hardware design of the tilted wheel and the experimental setup behind both standalone and spherical air-bearing tables used to test it. Experimental results from the air bearing table are provided with the results depicting the high performance capabilities of the proposed actuator in torque generation.

  18. Cosmic rays and other space weather effects influenced on satellite operation, technologies, biosphere and people health

    Science.gov (United States)

    Lev, Dorman

    2016-07-01

    Satellite anomalies (or malfunctions), including total distortion of electronics and loose of some satellites cost for Insurance Companies billions dollars per year. During especially active periods the probability of big satellite anomalies and their loosing increased very much. Now, when a great number of civil and military satellites are continuously worked for our practice life, the problem of satellite anomalies became very important. Many years ago about half of satellite anomalies were caused by technical reasons (for example, for Russian satellites Kosmos), but with time with increasing of production quality, this part became smaller and smaller. The other part, which now is dominated, caused by different space weather effects (energetic particles of CR and generated/trapped in the magnetosphere, and so on). We consider only satellite anomalies not caused by technical reasons: the total number of such anomalies about 6000 events, and separately for high and low altitude orbit satellites (5000 and about 800 events, correspondingly for high and low altitude satellites). No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and solar proton event onsets for high (>1500 km) and low (account under developing of the anomaly frequency models and forecasting. We consider also influence of CR on frequency of gene mutations and evolution of biosphere (we show that if it will be no CR, the Earth's civilization will be start only after milliards years later, what will be too late), CR role in thunderstorm phenomena and discharges, space weather effects on space technologies and radiation effects from solar and galactic CR in dependence of cutoff rigidities and altitude, influence magnetic storms accompanied by CR Forbush-effects on people health (increasing frequency of infarct myocardial and brain strokes), increasing frequency of car

  19. Advanced Attitude Control af Pico Sized Satellites

    DEFF Research Database (Denmark)

    Larsen, Jesper A.; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

    2005-01-01

    accuracy of better than 5 degrees. Cost, size, weight and power requirements, on the other hand, impose selecting relative simple sensors and actuators which leads to an attitude control requirement of less than 1 degree. This precision is obtained by a combination of magnetorquers and momentum wheels...

  20. 78 FR 67132 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-11-08

    ... Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Air Force, DoD. ACTION: Meeting notice..., 2013 Vol. 78 No. 206. This new meeting notice is to inform GPS simulator manufacturers, who supply...

  1. 77 FR 70421 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2012-11-26

    ... Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Department of the Air Force, DoD. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS simulator manufacturers, who supply products...

  2. 78 FR 63459 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-10-24

    ... Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Department of the Air Force. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS simulator manufacturers, who supply products to the Department of Defense (DoD), and GPS simulator users, both government and DoD contractors...

  3. Uplink Power Control For Earth/Satellite/Earth Communication

    Science.gov (United States)

    Chakraborty, Dayamoy

    1994-01-01

    Proposed control subsystem adjusts power radiated by uplink transmitter in Earth station/satellite relay station/ Earth station communication system. Adjustments made to compensate for anticipated changes in attenuation by rain. Raw input is a received downlink beacon singal, amplitude of which affected not only by rain fade but also by scintillation, attenuation in atmospheric gases, and diurnal effects.

  4. A Fault tolerant Control Supervisory System development Procedurefor Small Satellites

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Larsen, Jesper Abildgaard

    The paper presents a stepwise procedure to develop a fault tolerant control system for small satellites. The procedure is illustrated through implementation on the AAUSAT-II spacecraft. As it is shown the presented procedure requires expertise from several disciplines that are nevertheless...

  5. Satellite Dynamics and Control in a Quaternion Formulation (2nd edition)

    DEFF Research Database (Denmark)

    Blanke, Mogens; Larsen, Martin Birkelund

    This lecture note treats modelling and attitude control design using a quaternion description of attitude for a rigid body in space. Dynamics and kinematics of a satellite is formulated as a non-linear model from Euler’s moment equations and a description of kinematics using the attitude quaternion...... to represent rotation. A general linearised model is derived such that the user can specify an arbitrary point of operation in angular velocity and wheel angular momentum, specifying the a inertia matrix for a rigid satellite. A set of Simulink® models that simulate the satellite’s nonlinear behaviour...

  6. The Use of Satellite Data in the Operational 3D Coupled Ecosystem Model of the Baltic Sea (3D Cembs

    Directory of Open Access Journals (Sweden)

    Nowicki Artur

    2016-01-01

    Full Text Available The objective of this paper is to present an automatic monitoring system for the 3D CEMBS model in the operational version. This predictive, eco hydrodynamic model is used as a tool to control the conditions and bio productivity of the Baltic sea environment and to forecast physical and ecological changes in the studied basin. Satellite-measured data assimilation is used to constrain the model and achieve higher accuracy of its results.

  7. Attitude Control of a Satellite by using Digital Signal Processing

    Directory of Open Access Journals (Sweden)

    Adirelle C. Santana

    2012-03-01

    Full Text Available This article has discussed the development of a three-axis attitude digital controller for an artificial satellite using a digital signal processor. The main motivation of this study is the attitude control system of the satellite Multi-Mission Platform, developed by the Brazilian National Institute for Space Research for application in different sort of missions. The controller design was based on the theory of the Linear Quadratic Gaussian Regulator, synthesized from the linearized model of the motion of the satellite, i.e., the kinematics and dynamics of attitude. The attitude actuators considered in this study are pairs of cold gas jets powered by a pulse width/pulse frequency modulator. In the first stage of the project development, a system controller for continuous time was studied with the aim of testing the adequacy of the adopted control. The next steps had included an analysis of discretization techniques, the setting time of sampling rate, and the testing of the digital version of the Linear Quadratic Gaussian Regulator controller in the MATLAB/SIMULINK. To fulfill the study, the controller was implemented in a digital signal processor, specifically the Blackfin BF537 from Analog Devices, along with the pulse width/pulse frequency modulator. The validation tests used a scheme of co-simulation, where the model of the satellite was simulated in MATLAB/SIMULINK, while the controller and modulator were processed in the digital signal processor with a tool called Processor-In-the-Loop, which acted as a data communication link between both environments.function and required time to achieve a given mission accuracy are determined, and results are provided as illustration.

  8. The long-term effects of space weather on satellite operations

    Directory of Open Access Journals (Sweden)

    D. T. Welling

    2010-06-01

    Full Text Available Integrated lifetime radiation damage may cause spacecraft to become more susceptible to operational anomalies by changing material characteristics of electronic components. This study demonstrates and quantifies the impact of these effects by examining the National Oceanic and Atmospheric Administration (NOAA National Geophysical Data Center (NGDC satellite anomaly database. Energetic particle data from the Geostationary Operational Environmental Satellites (GOES is used to construct the total lifetime particle exposure a satellite has received at the epoch of an anomaly. These values are compared to the satellite's chronological age and the average exposure per year (calculated over two solar cycles. The results show that many anomalies occur on satellites that have received a total lifetime high-energy particle exposure that is disproportionate to their age. In particular, 10.8% of all events occurred on satellites that received over two times more 20 to 40 MeV proton lifetime particle exposure than predicted using an average annual mean. This number inflates to 35.2% for 40 to 80 MeV protons and 33.7% for ≥2 MeV electrons. Overall, 73.5% of all anomalies occurred on a spacecraft that had experienced greater than two times the expected particle exposure for one of the eight particle populations used in this study. Simplistically, this means that the long term radiation background exposure matters, and that if the background radiation is elevated during the satellite's lifetime, the satellite is likely to experience more anomalies than satellites that have not been exposed to the elevated environment.

  9. An active attitude control system for a drag sail satellite

    Science.gov (United States)

    Steyn, Willem Herman; Jordaan, Hendrik Willem

    2016-11-01

    The paper describes the development and simulation results of a full ADCS subsystem for the deOrbitSail drag sail mission. The deOrbitSail satellite was developed as part of an European FP7 collaboration research project. The satellite was launched and commissioning started on 10th July 2015. Various new actuators and sensors designed for this mission will be presented. The deOrbitSail satellite is a 3U CubeSat to deploy a 4 by 4 m drag sail from an initial 650 km circular polar low earth orbit. With an active attitude control system it will be shown that by maximising the drag force, the expected de-orbiting period from the initial altitude will be less than 50 days. A future application of this technology will be the use of small drag sails as low-cost devices to de-orbit LEO satellites, when they have reached their end of life, without having to use expensive propulsion systems. Simulation and Hardware-in-Loop experiments proved the feasibility of the proposed attitude control system. A magnetic-only control approach using a Y-Thomson spin, is used to detumble the 3U Cubesat with stowed sail and subsequently to 3-axis stabilise the satellite to be ready for the final deployment phase. Minituarised torquer rods, a nano-sized momentum wheel, attitude sensor hardware (magnetometer, sun, earth) developed for this phase will be presented. The final phase will be to deploy and 3-axis stabilise the drag sail normal to the satellite's velocity vector, using a combined Y-momentum wheel and magnetic controller. The design and performance improvements when using a 2-axis translation stage to adjust the sail centre-of-pressure to satellite centre-of-mass offset, will also be discussed, although for launch risk reasons this stage was not included in the final flight configuration. To accurately determine the drag sail's attitude during the sunlit part of the orbit, an accurate wide field of view dual sensor to measure both the sun and nadir vector direction was developed for

  10. HVAC controls: Operation and maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Gupton, G.W. Jr.

    1987-01-01

    The introductory chapters review HVAC system processes and equipment, control system types and equipment, and equipment-to-control interactions. The succeeding chapters cover specific control systems functions, including electrical interlock and motor starting, electrical and electronic control system diagrams, pneumatic control system diagrams, air supply to pneumatic control systems, and control system maintenance.

  11. 3-Axis magnetic control: flight results of the TANGO satellite in the PRISMA mission

    Science.gov (United States)

    Chasset, C.; Noteborn, R.; Bodin, P.; Larsson, R.; Jakobsson, B.

    2013-09-01

    PRISMA implements guidance, navigation and control strategies for advanced formation flying and rendezvous experiments. The project is funded by the Swedish National Space Board and run by OHB-Sweden in close cooperation with DLR, CNES and the Danish Technical University. The PRISMA test bed consists of a fully manoeuvrable MANGO satellite as well as a 3-axis controlled TANGO satellite without any Δ V capability. PRISMA was launched on the 15th of June 2010 on board DNEPR. The TANGO spacecraft is the reference satellite for the experiments performed by MANGO, either with a "cooperative" or "non-cooperative" behaviour. Small, light and low-cost were the keywords for the TANGO design. The attitude determination is based on Sun sensors and magnetometers, and the active attitude control uses magnetic torque rods only. In order to perform the attitude manoeuvres required to fulfil the mission objectives, using any additional gravity gradient boom to passively stabilize the spacecraft was not allowed. After a two-month commissioning phase, TANGO separated from MANGO on the 11th of August 2010. All operational modes have been successfully tested, and the pointing performance in flight is in accordance with expectations. The robust Sun Acquisition mode reduced the initial tip-off rate and placed TANGO into a safe attitude in TANGO points its GPS antenna towards zenith with sufficient accuracy to track as many GPS satellites as MANGO. At the same time, it points its solar panel towards the Sun, and all payload equipments can be switched on without any restriction. This paper gives an overview of the TANGO Attitude Control System design. It then presents the flight results in the different operating modes. Finally, it highlights the key elements at the origin of the successful 3-axis magnetic control strategy on the TANGO satellite.

  12. Networked Operations of Hybrid Radio Optical Communications Satellites

    Science.gov (United States)

    Hylton, Alan; Raible, Daniel

    2014-01-01

    In order to address the increasing communications needs of modern equipment in space, and to address the increasing number of objects in space, NASA is demonstrating the potential capability of optical communications for both deep space and near-Earth applications. The Integrated Radio Optical Communications (iROC) is a hybrid communications system that capitalizes on the best of both the optical and RF domains while using each technology to compensate for the other's shortcomings. Specifically, the data rates of the optical links can be higher than their RF counterparts, whereas the RF links have greater link availability. The focus of this paper is twofold: to consider the operations of one or more iROC nodes from a networking point of view, and to suggest specific areas of research to further the field. We consider the utility of Disruption Tolerant Networking (DTN) and the Virtual Mission Operation Center (VMOC) model.

  13. Summary of the CTS Transient Event Counter data after one year of operation. [Communication Technology Satellite

    Science.gov (United States)

    Stevens, N. J.; Klinect, V. W.; Gore, J. V.

    1977-01-01

    The environmental charging of satellite surfaces during geomagnetic substorms is the apparent cause of a significant number of anomalous events occurring on geosynchronous satellites since the early 1970's. Electromagnetic pulses produced in connection with the differential charging of insulators can couple into the spacecraft harness and cause electronic switching anomalies. An investigation conducted to determine the response of the spacecraft surfaces to substorm particle fluxes makes use of a harness transient detector. The harness transient detector, called the Transient Event Counter (TEC) was built and integrated into the Canadian-American Communications Technology Satellite (CTS). A description of the TEC and its operational characteristics is given and the obtained data are discussed. The data show that the satellite surfaces appear to be charged to the point that discharges occur and that the discharge-induced transients couple into the wire harnesses.

  14. Autonomous Attitude Determination and Control System for the Ørsted Satellite

    DEFF Research Database (Denmark)

    Bak, Thomas; Wisniewski, Rafal; Blanke, M.

    1996-01-01

    The Ørsted Satellite mission imposes comparatively high requirements on autonomy of the attitude control system.......The Ørsted Satellite mission imposes comparatively high requirements on autonomy of the attitude control system....

  15. Satellite-aided mobile communications limited operational test in the trucking industry

    Science.gov (United States)

    Anderson, R. E.; Frey, R. L.; Lewis, J. R.

    1980-01-01

    An experiment with NASA's ATS-6 satellite, that demonstrates the practicality of satellite-aided land mobile communications is described. Satellite communications equipment for the experiment was designed so that it would be no more expensive, when mass produced, than conventional two-way mobile radio equipment. It embodied the operational features and convenience of present day mobile radios. Vehicle antennas 75 cm tall and 2 cm in diameter provided good commercial quality signals to and from trucks and jeeps. Operational applicability and usage data were gathered by installing the radio equipment in five long-haul tractor-trailer trucks and two Air Force search and rescue jeeps. Channel occupancy rates are reported. Air Force personnel found the satellite radio system extremely valuable in their search and rescue mission during maneuvers and actual rescue operations. Propagation data is subjectively analyzed and over 4 hours of random data is categorized and graded as to signal quality on a second by second basis. Trends in different topographic regions are reported. An overall communications reliability of 93% was observed despite low satellite elevation angles ranging from 9 to 24 degrees.

  16. Groebner Basis Solutions to Satellite Trajectory Control by Pole Placement

    Science.gov (United States)

    Kukelova, Z.; Krsek, P.; Smutny, V.; Pajdla, T.

    2013-09-01

    Satellites play an important role, e.g., in telecommunication, navigation and weather monitoring. Controlling their trajectories is an important problem. In [1], an approach to the pole placement for the synthesis of a linear controller has been presented. It leads to solving five polynomial equations in nine unknown elements of the state space matrices of a compensator. This is an underconstrained system and therefore four of the unknown elements need to be considered as free parameters and set to some prior values to obtain a system of five equations in five unknowns. In [1], this system was solved for one chosen set of free parameters with the help of Dixon resultants. In this work, we study and present Groebner basis solutions to this problem of computation of a dynamic compensator for the satellite for different combinations of input free parameters. We show that the Groebner basis method for solving systems of polynomial equations leads to very simple solutions for all combinations of free parameters. These solutions require to perform only the Gauss-Jordan elimination of a small matrix and computation of roots of a single variable polynomial. The maximum degree of this polynomial is not greater than six in general but for most combinations of the input free parameters its degree is even lower. [1] B. Palancz. Application of Dixon resultant to satellite trajectory control by pole placement. Journal of Symbolic Computation, Volume 50, March 2013, Pages 79-99, Elsevier.

  17. Semi-active Attitude Control and Off-line Attitude Determination for the SSETI-Express Student Micro-satellite

    OpenAIRE

    Alminde, Lars

    2005-01-01

    This paper concerns the development of the Attitude Determination and Control System (ADCS) for the SSETI-Express micro-satellite mission. The mission is an educational project involving 14 universities and the European Space Agency (ESA). The satellite has been designed and built, by students, over a period of only 18 months. This paper emphasises on the trade-offs required to build an operational ADCS system within such a rapidly developing project.

  18. Umatilla Hatchery Satellite Facilities Operation and Maintenance; 1995 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Rowan, Gerald D.

    1996-05-01

    The Confederated Tribes of the Umatilla Indian Reservoir (CTUIR) and Oregon Department of Fish and Wildlife (ODFW) are cooperating in a joint effort to enhance steelhead and re-establish salmon runs in the Umatilla River Basin. As an integral part of this program, Bonifer Pond, Minthorn Springs, Imeques C-mem-ini-kem and Thornhollow facilities are operated for acclimation and release of juvenile summer steelhead (Oncorhynchus mykiss), fall and spring chinook salmon (O. tshawytscha) and coho salmon (O. kisutch). Minthorn is also used for holding and spawning adult summer steelhead, fall chinook and coho salmon. Personnel from the ODFW Eastern Oregon Fish Pathology Laboratory in La Grande took samples of tissues and reproductive fluids from Umatilla River summer steelhead and coho salmon broodstock for monitoring and evaluation purposes. Coded-wire tag recovery information was accessed to determine the contribution of Umatilla river releases to ocean, Columbia River and Umatilla River fisheries.

  19. Co-operatives and Normative Control

    DEFF Research Database (Denmark)

    Bregn, Kirsten; Jagd, Søren

    1992-01-01

    This paper explores the conditions for applying normative control in co-operatives. For normative control to be effective two conditions are found particularly important: Individuals must be morally involved and the organization must have a system of making it possible to link common norms...... and individual action. If these conditions are not fulfilled, as may be the case in many co-operatives, normative control cannot be expected to work. The problems of normative control in co-operatives may then not be caused by the use of normative control as such, but may instead be a problem of securing...... the conditions necessary for normative control. This is illustrated by a case study of control in a Danish producers co-operative. The analysis of the case study leads to the hypothesis of a paradox of normative control in co-operatives: The need of information tends to be greater in co-operatives comparet...

  20. Attitude control for part actuator failure of agile small satellite

    Institute of Scientific and Technical Information of China (English)

    J. R. Zhang; A. Rachid; Y. Zhang

    2008-01-01

    The stability and singularity problem of agile small satellite (ASS) with actuator failure is discussed in this paper. Firstly, the three-axis stabilized controller of an ASS is designed, where micro control moment gyros (MCMG's) in pyramid configuration (PC) is used as the actuator. By using the same controller and steering law, the control results before and after one gyro fails are compared by simulation. The variation of singular momentum envelope before and after one gyro fails is also compared. The simulation results show that the failure intensively decreases the capacity of output torque, which leads to the emergence of more singular points and the rapid saturation of MCMG's. Finally, the parameters of system controller are changed to compare the control effect.

  1. Application of altitude control techniques for low altitude earth satellites

    Science.gov (United States)

    Nickerson, K. G.; Herder, R. W.; Glass, A. B.; Cooley, J. L.

    1977-01-01

    The applications sensors of many low altitude earth satellites designed for recording surface or atmospheric data require near zero orbital eccentricities for maximum usefulness. Coverage patterns and altitude profiles require specified values of orbit semimajor axis. Certain initial combinations of semimajor axis, eccentricity, and argument of perigee can produce a so called 'frozen orbit' and minimum altitude variation which enhances sensor coverage. This paper develops information on frozen orbits and minimum altitude variation for all inclinations, generalizing previous results. In the altitude regions where most of these satellites function (between 200 and 1000 kilometers) strong atmospheric drag effects influence the evolution of the initial orbits. Active orbital maneuver control techniques to correct evolution of orbit parameters while minimizing the frequency of maneuvers are presented. The paper presents the application of theoretical techniques for control of near frozen orbits and expands upon the methods useful for simultaneously targeting several inplane orbital parameters. The applications of these techniques are illustrated by performance results from the Atmosphere Explorer (AE-3 and -5) missions and in preflight maneuver analysis and plans for the Seasat Oceanographic Satellite.

  2. A study of multiple access schemes in satellite control network

    Science.gov (United States)

    Mo, Zijian; Wang, Zhonghai; Xiang, Xingyu; Wang, Gang; Chen, Genshe; Nguyen, Tien; Pham, Khanh; Blasch, Erik

    2016-05-01

    Satellite Control Networks (SCN) have provided launch control for space lift vehicles; tracking, telemetry and commanding (TTC) for on-orbit satellites; and, test support for space experiments since the 1960s. Currently, SCNs encounter a new challenge: how to maintain the high reliability of services when sharing the spectrum with emerging commercial services. To achieve this goal, the capability of multiple satellites reception is deserved as an update/modernization of SCN in the future. In this paper, we conducts an investigation of multiple access techniques in SCN scenario, e.g., frequency division multiple access (FDMA) and coded division multiple access (CDMA). First, we introduce two upgrade options of SCN based on FDMA and CDMA techniques. Correspondingly, we also provide their performance analysis, especially the system improvement in spectrum efficiency and interference mitigation. Finally, to determine the optimum upgrade option, this work uses CRISP, i.e., Cost, Risk, Installation, Supportability and Performance, as the baseline approach for a comprehensive trade study of these two options. Extensive numerical and simulation results are presented to illustrate the theoretical development.

  3. A Comparative Study of Actuator Configurations for Satellite Attitude Control

    Directory of Open Access Journals (Sweden)

    Raymond Kristiansen

    2005-10-01

    Full Text Available In this paper a controllability study of different actuator configurations consisting of magnetic torquers, reaction wheels and a gravity boom is presented. The theoretical analysis is performed with use of controllability gramians, and simulation results with the different configurations are presented and compared regarding settling time and power consumption to substantiate the theoretical analysis. A reference model is also introduced to show how the power consumption can he lowered to the same magnitude as when magnetic torquers are used, without degrading the satellite response significantly.

  4. Satellite Formation Control Using the Approximating Sequence Riccati Equations

    Directory of Open Access Journals (Sweden)

    Ashraf H. Owis

    2013-11-01

    Full Text Available In this study we develop a reliable algorithm to control the satellite formation using the Approximating Sequence of Riccati Equations(ASRE minimizing the fuel consumption and the deviation of the orbit from the nominal orbit. The nonlinear Clohessy -Wiltshire(CW equations of motions are used to describe the motion of the satellite formation about a virtual reference position maintained at the formation center. The nonlinear dynamics of the system will be factorized in such a way that the new factorized system is accessible. The problem is tackled using the Approximating Sequence Riccati Equations(ASRE method. The technique is based on Linear Quadratic Regulator (LQR with fixed terminal state, which guarantees closed loop solution.

  5. Operation and maintenance of Fermilab`s satellite refrigerator expansion engines

    Energy Technology Data Exchange (ETDEWEB)

    Soyars, W.M.

    1996-09-01

    Fermilab`s superconducting Tevatron accelerator is cooled to liquid helium temperatures by 24 satellite refrigerators, each of which uses for normal operations a reciprocating `wet` expansion engine. These expanders are basically Process System (formerly Koch) Model 1400 expanders installed in standalone cryostats designed by Fermilab. This paper will summarize recent experience with operations and maintenance of these expansion engines. Some of the statistics presented will include total engine hours, mean time between major and minor maintenance, and frequent causes of major maintenance.

  6. Guidance, Navigation, and Control System for Maneuverable Pico-Satellites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Pico-satellites are an emerging new class of spacecraft. Maneuverable pico-satellites require active guidance, navigation, and control (GN&C) systems to perform...

  7. Control-based operating system design

    CERN Document Server

    Leva, Alberto; Papadopoulos, AV; Terraneo, F

    2013-01-01

    This book argues that computer operating system components should be conceived from the outset as controllers, synthesised and assessed in the system-theoretical world of dynamic models, and then realised as control algorithms.

  8. Efficient medium access control protocol for geostationary satellite systems

    Institute of Scientific and Technical Information of China (English)

    王丽娜; 顾学迈

    2004-01-01

    This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

  9. Anti-Satellite Weapons, Countermeasures, and Arms Control

    Science.gov (United States)

    2007-11-02

    From Kosmos 1500 38 3-3. Imagery Obtained by Synthetic-Aperture Satellite Radar 40 Chapter 3 MILSATs, ASATs, and National Security THE ROLE AND...satellite capabil- ities, such as resolution. For example, Soviet oceanographic radar satellites of the Kosmos - 1500 class can obtain radar imagery with...surveillance satellite ( Kosmos 1500) equipped with a side-looking radar and in the same year placed two satellites (Venera 15 and Venera 16) equipped

  10. Controlling operational risk: Concepts and practices

    NARCIS (Netherlands)

    van den Tillaart, A.H.A.J.

    2003-01-01

    The subject of this thesis is controlling 'operational risk' in banks. Operational risk is defined as the risk of losses resulting from inadequate or failed internal processes, people, systems, or from external events. Within this very broad subject, we focus on the place of operational risk

  11. A class of symmetric controlled quantum operations

    CERN Document Server

    Vaccaro, J A; Huelga, S F; Vaccaro, John A.

    2001-01-01

    Certain quantum gates, such as the controlled-NOT gate, are symmetric in terms of the operation of the control system upon the target system and vice versa. However, no operational criteria yet exist for establishing whether or not a given quantum gate is symmetrical in this sense. We consider a restricted, yet broad, class of two-party controlled gate operations for which the gate transforms a reference state of the target into one of an orthogonal set of states. We show that for this class of gates it is possible to establish a simple necessary and sufficient condition for the gate operation to be symmetric.

  12. A class of symmetric controlled quantum operations

    Energy Technology Data Exchange (ETDEWEB)

    Vaccaro, John A.; Steuernagel, O.; Huelga, S.F. [Division of Physics and Astronomy, Department of Physical Sciences, University of Hertfordshire, Hatfield (United Kingdom)

    2001-09-07

    Certain quantum gates, such as the controlled-NOT gate, are symmetric in terms of the operation of the control system upon the target system and vice versa. However, no operational criteria yet exist for establishing whether or not a given quantum gate is symmetrical in this sense. We consider a restricted, yet broad, class of two-party controlled gate operations for which the gate transforms a reference state of the target into one of an orthogonal set of states. We show that for this class of gates it is possible to establish a simple necessary and sufficient condition for the gate operation to be symmetric. (author)

  13. Controlling the Chaos Using Fuzzy Estimation in a Gyrostat Satellite

    Science.gov (United States)

    Guran, Ardeshir

    In this paper, we present a study of the dynamical behavior in a Kelvin type gyrostat satellite. We firstly obtain the Hamiltonian equations of our model by using Cardan angles as generalized coordinates. Then, we make this Hamiltonian dimensionless and calculate motion equations for this dimensionless system. The study of the Poincare's sections of this system shows us that chaotic motion regimes are present for specific parameter values. The main goal of this work is the finding of stabilizing orbits by using a control technique, the fuzzy control of Poincare map method, so that it can be applied to stabilize special periodic orbits in this system. Finally, we expect that the technique can be useful for a better understanding of control theory and their applications in gyrostat problems.

  14. TCP-ATCA: Improved Transmission Control Algorithm in Satellite Network

    Institute of Scientific and Technical Information of China (English)

    Liu Feng; Liu Hengna; Zhao Han

    2008-01-01

    An adaptive transmission control algorithm based on TCP (TCP-ATCA) is proposed to reduce the effects of long propagation de- lay and high link error rate of the satellite network on the performances. The flow control and the error recovery are differentiated by combined dynamic random early detection-explicit congestion notification (DRED-ECN) algorithm, and, moreover, the pertaining con- gestion control methods are used in TCP-ATCA to improve the throughput. By introducing the entire recovery algorithm, the unneces- sary congestion window decrease is reduced, and the throughput and fairness are improved. Simulation results show that, compared with TCP-Reno, TCP-ATCA provides a better throughput performance when the link capacity is higher (≥ 600 packet/s), and roughly the same when it is lower. At the same time, TCP-ATCA also increases fairness and reduces transmission delay.

  15. Operational climate monitoring from space: the EUMETSAT satellite application facility on climate monitoring (CM-SAF

    Directory of Open Access Journals (Sweden)

    J. Schulz

    2008-05-01

    Full Text Available The Satellite Application Facility on Climate Monitoring (CM-SAF aims at the provision of satellite-derived geophysical parameter data sets suitable for climate monitoring. CM-SAF provides climatologies for Essential Climate Variables (ECV, as required by the Global Climate Observing System implementation plan in support of the UNFCCC. Several cloud parameters, surface albedo, radiation fluxes at the top of the atmosphere and at the surface as well as atmospheric temperature and humidity products form a sound basis for climate monitoring of the atmosphere. The products are categorized in monitoring data sets obtained in near real time and data sets based on carefully intercalibrated radiances. The CM-SAF products are derived from several instruments on-board operational satellites in geostationary and polar orbit, i.e., the Meteosat and NOAA satellites, respectively. The existing data sets will be continued using data from the instruments on-board the new EUMETSAT Meteorological Operational satellite (MetOP. The products have mostly been validated against several ground-based data sets both in situ and remotely sensed. The accomplished accuracy for products derived in near real time is sufficient to monitor variability on diurnal and seasonal scales. Products based on intercalibrated radiance data can also be used for climate variability analysis up to inter-annual scale. A central goal of the recently started Continuous Development and Operations Phase of the CM-SAF (2007–2012 is to further improve all CM-SAF data sets to a quality level that allows for studies of inter-annual variability.

  16. Short-Term Prediction Research and Transition (SPoRT) Center: Transitioning Satellite Data to Operations

    Science.gov (United States)

    Zavodsky, Bradley

    2012-01-01

    The Short-term Prediction Research and Transition (SPoRT) Center located at NASA Marshall Space Flight Center has been conducting testbed activities aimed at transitioning satellite products to National Weather Service operational end users for the last 10 years. SPoRT is a NASA/NOAA funded project that has set the bar for transition of products to operational end users through a paradigm of understanding forecast challenges and forecaster needs, displaying products in end users decision support systems, actively assessing the operational impact of these products, and improving products based on forecaster feedback. Aiming for quality partnerships rather than a large quantity of data users, SPoRT has become a community leader in training operational forecasters on the use of up-and-coming satellite data through the use of legacy instruments and proxy data. Traditionally, SPoRT has supplied satellite imagery and products from NASA instruments such as the Moderate-resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS). However, recently, SPoRT has been funded by the GOES-R and Joint Polar Satellite System (JPSS) Proving Grounds to accelerate the transition of selected imagery and products to help improve forecaster awareness of upcoming operational data from the Visible Infrared Imager Radiometer Suite (VIIRS), Cross-track Infrared Sounder (CrIS), Advanced Baseline Imager (ABI), and Geostationary Lightning Mapper (GLM). This presentation provides background on the SPoRT Center, the SPoRT paradigm, and some example products that SPoRT is excited to work with forecasters to evaluate.

  17. Novel architecture for data management and control for small satellite

    Science.gov (United States)

    Adami, G.; Fossati, D.; Turri, M.

    1995-12-01

    The paper introduces an innovative architecture for the on-board units that are responsible to provide the data interface, control and processing capability normally allocated in separated electronics boxes in the data handling subsystem of the space system. A new solution for the attitude control of the space vehicle has been studied and developed and the utilization of this technological growth, in particular that concerns the GPS receiver, is matter for novel architecture. This new approach also involves in general the small satellite ground segment product as matter of a dedicated development approach. Small and medium satellites are considered an attractive solution for the low cost scientific experimentation, communication or remote sensing satellites. The functional and performance capability of the studied on-board units and ground segment are assessed in tight conjunction with the evolution of the European and the USA market. The design of these units has to be based on few and simple driving requirements, directly derived from the new modified scenario: (1) The limited budgets available for space system. (2) The quick mission data return, i.e., low development time by specific and tailored system development tools. The quick availability of data to scientists/user is requested without jeopardizing the maximum and guaranteed scientific or commercial return. The proposed system is then given thinking to an architecture based on a high degree of modularity (and reuse of existing library of modules) thus allowing to keep down costs and to speed up the time to market. The design ground rules are so established in order to cope with the following performance: (1) capability to adapt with few impacts the system interfaces, in particular for attitude sensors and actuators that are tightly mission dependent; (2) easy adaptation of on board computational performances and memory capacity (including mass memory storage capability); (3) definition of a hierarchical

  18. General predictive control using the delta operator

    DEFF Research Database (Denmark)

    Jensen, Morten Rostgaard; Poulsen, Niels Kjølstad; Ravn, Ole

    1993-01-01

    This paper deals with two-discrete-time operators, the conventional forward shift-operator and the δ-operator. Both operators are treated in view of construction of suitable solutions to the Diophantine equation for the purpose of prediction. A general step-recursive scheme is presented. Finally...... a general predictive control (GPC) is formulated and applied adaptively to a continuous-time plant...

  19. Optimizing the Attitude Control of Small Satellite Constellations for Rapid Response Imaging

    Science.gov (United States)

    Nag, S.; Li, A.

    2016-12-01

    Distributed Space Missions (DSMs) such as formation flight and constellations, are being recognized as important solutions to increase measurement samples over space and time. Given the increasingly accurate attitude control systems emerging in the commercial market, small spacecraft now have the ability to slew and point within few minutes of notice. In spite of hardware development in CubeSats at the payload (e.g. NASA InVEST) and subsystems (e.g. Blue Canyon Technologies), software development for tradespace analysis in constellation design (e.g. Goddard's TAT-C), planning and scheduling development in single spacecraft (e.g. GEO-CAPE) and aerial flight path optimizations for UAVs (e.g. NASA Sensor Web), there is a gap in open-source, open-access software tools for planning and scheduling distributed satellite operations in terms of pointing and observing targets. This paper will demonstrate results from a tool being developed for scheduling pointing operations of narrow field-of-view (FOV) sensors over mission lifetime to maximize metrics such as global coverage and revisit statistics. Past research has shown the need for at least fourteen satellites to cover the Earth globally everyday using a LandSat-like sensor. Increasing the FOV three times reduces the need to four satellites, however adds image distortion and BRDF complexities to the observed reflectance. If narrow FOV sensors on a small satellite constellation were commanded using robust algorithms to slew their sensor dynamically, they would be able to coordinately cover the global landmass much faster without compensating for spatial resolution or BRDF effects. Our algorithm to optimize constellation satellite pointing is based on a dynamic programming approach under the constraints of orbital mechanics and existing attitude control systems for small satellites. As a case study for our algorithm, we minimize the time required to cover the 17000 Landsat images with maximum signal to noise ratio fall

  20. Power generation, operation and control

    CERN Document Server

    Wood, Allen J; Sheblé, Gerald B

    2013-01-01

    Since publication of the second edition, there have been extensive changes in the algorithms, methods, and assumptions in energy management systems that analyze and control power generation. This edition is updated to acquaint electrical engineering students and professionals with current power generation systems. Algorithms and methods for solving integrated economic, network, and generating system analysis are provided. Also included are the state-of-the-art topics undergoing evolutionary change, including market simulation, multiple market analysis, multiple interchange contract analysis, c

  1. Computer control for remote wind turbine operation

    Energy Technology Data Exchange (ETDEWEB)

    Manwell, J.F.; Rogers, A.L.; Abdulwahid, U.; Driscoll, J. [Univ. of Massachusetts, Amherst, MA (United States)

    1997-12-31

    Light weight wind turbines located in harsh, remote sites require particularly capable controllers. Based on extensive operation of the original ESI-807 moved to such a location, a much more sophisticated controller than the original one has been developed. This paper describes the design, development and testing of that new controller. The complete control and monitoring system consists of sensor and control inputs, the control computer, control outputs, and additional equipment. The control code was written in Microsoft Visual Basic on a PC type computer. The control code monitors potential faults and allows the turbine to operate in one of eight states: off, start, run, freewheel, low wind shut down, normal wind shutdown, emergency shutdown, and blade parking. The controller also incorporates two {open_quotes}virtual wind turbines,{close_quotes} including a dynamic model of the machine, for code testing. The controller can handle numerous situations for which the original controller was unequipped.

  2. Control of industrial robots for hardware-in-the-loop simulation of satellite docking

    Science.gov (United States)

    Ma, Ou; Zebenay, Melak; Boge, Toralf

    2011-06-01

    One of the most challenging and risky missions for spacecraft is to perform Rendezvous and Docking (RvD) autonomously in space. To ensure a safe and reliable operation, such a mission must be carefully designed and thoroughly verified before a real space mission can be launched. This paper describes the impact-contact dynamics simulation capability of a new, robotics-based, hardware-in-the-loop (HIL) RvD simulation facility which uses two industrial robots to simulate 6-DOF dynamic maneuvering of two docking satellites. The facility is capable of physically simulating the final approaching within 25-meter range and the entire docking/capturing process in a satellite on-orbit servicing mission. The paper briefly discusses the difficulties of using industrial robots for HIL contact dynamics simulation and how these problems are solved. Admittance control strategy is proposed to control the robotic system to make the robot dynamically behave like the spacecraft during a physical interception. The control strategy works as an outer loop on the top of the existing control system of the industrial robot and hence, it does not require altering the joint control hardware and software which are inaccessible for an industrial robot. A simulation study has shown that the methodology can accurately simulate the impact-contact dynamics behavior of the spacecraft in a docking operation.

  3. Attitude control of a small satellite using magnetic bearing momentum wheel

    OpenAIRE

    Terui, Fuyuto; Nakajima, Atsushi; 照井 冬人; 中島 厚

    1996-01-01

    An attitude controller for a 50 kg-class micro satellite which could be launched by H-2 rocket as a piggyback payload of a main satellite is considered. The survey of the proposals of the mission using a micro satellite from national institutes, universities and private companies shows that the development of a small, light and inexpensive three axis attitude controller is widely expected. One of the candidate configurations for such an attitude controller is bias momentum control using a mag...

  4. GHRSST Level 2P Western Atlantic Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-13 satellite (GDS versions 1 and 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

  5. GHRSST Level 2P Central Pacific Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-15 satellite (GDS versions 1 and 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

  6. Nuclear thermal rocket engine operation and control

    Science.gov (United States)

    Gunn, Stanley V.; Savoie, Margarita T.; Hundal, Rolv

    1993-06-01

    The operation of a typical Rover/Nerva-derived nuclear thermal rocket (NTR) engine is characterized and the control requirements of the NTR are defined. A rationale for the selection of a candidate diverse redundant NTR engine control system is presented and the projected component operating requirements are related to the state of the art of candidate components and subsystems. The projected operational capabilities of the candidate system are delineated for the startup, full-thrust, shutdown, and decay heat removal phases of the engine operation.

  7. Command and control displays for space vehicle operations

    Science.gov (United States)

    Desjardins, Daniel D.; Zetocha, Paul; Aleva, Denise

    2010-04-01

    This paper shall examine several command and control facility display architectures supporting space vehicle operations, to include TacSat 2, TacSat 3, STPSat 2, and Communications Navigation Outage Forecasting System (CNOFS), located within the Research Development Test & Evaluation Support Complex (RSC) Satellite Operations Center 97 (SOC-97) at Kirtland Air Force Base. A principal focus is to provide an understanding for the general design class of displays currently supporting space vehicle command and control, e.g., custom, commercial-off-the-shelf, or ruggedized commercial-off-the-shelf, and more specifically, what manner of display performance capabilities, e.g., active area, resolution, luminance, contrast ratio, frame/refresh rate, temperature range, shock/vibration, etc., are needed for particular aspects of space vehicle command and control. Another focus shall be to address the types of command and control functions performed for each of these systems, to include how operators interact with the displays, e.g., joystick, trackball, keyboard/mouse, as well as the kinds of information needed or displayed for each function. [Comparison with other known command and control facilities, such as Cheyenne Mountain and NORAD Operations Center, shall be made.] Future, anticipated display systems shall be discussed.

  8. Passivity Based Nonlinear Attitude Control of the Rømer Satellite

    DEFF Research Database (Denmark)

    Quottrup, Michael Melholt; Krogh-Sørensen, J.; Wisniewski, Rafal

    2001-01-01

    This paper suggests nonlinear attitude control of the Danish satellite Rømer. This satellite will be designed to fulfil two scientific objectives: The observation of stellar oscillations and the detection and localisation of gamma-ray bursts. The satellite will be equipped with a tetrahedron...

  9. Passivity based nonlinear attitude control of the Rømer satellite

    DEFF Research Database (Denmark)

    Quottrup, Michael Melholt; Krogh-Sørensen, J.; Wisniewski, Rafal

    This paper suggests nonlinear attitude control of the Danish satellite Rømer. This satellite will be designed to fulfil two scientific objectives: The observation of stellar oscillations and the detection and localisation of gamma-ray bursts. The satellite will be equipped with a tetrahedron...

  10. Phase control system concepts and simulations. [solar power satellite system

    Science.gov (United States)

    Lindsay, V. C.

    1980-01-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  11. Co-operatives and Normative Control

    DEFF Research Database (Denmark)

    Bregn, Kirsten; Jagd, Søren

    1992-01-01

    This paper explores the conditions for applying normative control in co-operatives. For normative control to be effective two conditions are found particularly important: Individuals must be morally involved and the organization must have a system of making it possible to link common norms...... to other organizations because of the special features of co-operative organizations: use of normative control, democratic decision-making, and decentralized organizational structure. On the other hand, however, there may be strong barriers in co-operatives against creating a sufficient information system....

  12. Chapter 8: Plasma operation and control

    Science.gov (United States)

    Gribov, Y.; Humphreys, D.; Kajiwara, K.; Lazarus, E. A.; Lister, J. B.; Ozeki, T.; Portone, A.; Shimada, M.; Sips, A. C. C.; Wesley, J. C.

    2007-06-01

    The ITER plasma control system has the same functional scope as the control systems in present tokamaks. These are plasma operation scenario sequencing, plasma basic control (magnetic and kinetic), plasma advanced control (control of RWMs, NTMs, ELMs, error fields, etc) and plasma fast shutdown. This chapter considers only plasma initiation and plasma basic control. This chapter describes the progress achieved in these areas in the tokamak experiments since the ITER Physics Basis (1999 Nucl. Fusion 39 2577) was written and the results of assessment of ITER to provide the plasma initiation and basic control. This assessment was done for the present ITER design (15 MA machine) at a more detailed level than it was done for the ITER design 1998 (21 MA machine) described in the ITER Physics Basis (1999 Nucl. Fusion 39 2577). The experiments on plasma initiation performed in DIII-D and JT-60U, as well as the theoretical studies performed for ITER, have demonstrated that, within specified assumptions on the plasma confinement and the impurity influx, ITER can produce plasma initiation in a low toroidal electric field (0.3 V m-1), if it is assisted by about 2 MW of ECRF heating. The plasma basic control includes control of the plasma current, position and shape—the plasma magnetic control, as well as control of other plasma global parameters or their profiles—the plasma performance control. The magnetic control is based on more reliable and simpler models of the control objects than those available at present for the plasma kinetic control. Moreover the real time diagnostics used for the magnetic control in many cases are more precise than those used for the kinetic control. Because of these reasons, the plasma magnetic control was developed for modern tokamaks and assessed for ITER better than the kinetic control. However, significant progress has been achieved in the plasma performance control during the last few years. Although the physics basis of plasma operation

  13. An Object Model for Integrating Diverse Remote Sensing Satellite Sensors: A Case Study of Union Operation

    Directory of Open Access Journals (Sweden)

    Chuli Hu

    2014-01-01

    Full Text Available In the Earth Observation sensor web environment, the rapid, accurate, and unified discovery of diverse remote sensing satellite sensors, and their association to yield an integrated solution for a comprehensive response to specific emergency tasks pose considerable challenges. In this study, we propose a remote sensing satellite sensor object model, based on the object-oriented paradigm and the Open Geospatial Consortium Sensor Model Language. The proposed model comprises a set of sensor resource objects. Each object consists of identification, state of resource attribute, and resource method. We implement the proposed attribute state description by applying it to different remote sensors. A real application, involving the observation of floods at the Yangtze River in China, is undertaken. Results indicate that the sensor inquirer can accurately discover qualified satellite sensors in an accurate and unified manner. By implementing the proposed union operation among the retrieved sensors, the inquirer can further determine how the selected sensors can collaboratively complete a specific observation requirement. Therefore, the proposed model provides a reliable foundation for sharing and integrating multiple remote sensing satellite sensors and their observations.

  14. Modeling Control Situations in Power System Operations

    DEFF Research Database (Denmark)

    Saleem, Arshad; Lind, Morten; Singh, Sri Niwas

    2010-01-01

    Increased interconnection and loading of the power system along with deregulation has brought new challenges for electric power system operation, control and automation. Traditional power system models used in intelligent operation and control are highly dependent on the task purpose. Thus, a model...... for intelligent operation and control must represent system features, so that information from measurements can be related to possible system states and to control actions. These general modeling requirements are well understood, but it is, in general, difficult to translate them into a model because of the lack...... of explicit principles for model construction. This paper presents a work on using explicit means-ends model based reasoning about complex control situations which results in maintaining consistent perspectives and selecting appropriate control action for goal driven agents. An example of power system...

  15. Modeling Control Situations in Power System Operations

    DEFF Research Database (Denmark)

    Saleem, Arshad; Lind, Morten; Singh, Sri Niwas

    2010-01-01

    Increased interconnection and loading of the power system along with deregulation has brought new challenges for electric power system operation, control and automation. Traditional power system models used in intelligent operation and control are highly dependent on the task purpose. Thus, a model...... for intelligent operation and control must represent system features, so that information from measurements can be related to possible system states and to control actions. These general modeling requirements are well understood, but it is, in general, difficult to translate them into a model because of the lack...... of explicit principles for model construction. This paper presents a work on using explicit means-ends model based reasoning about complex control situations which results in maintaining consistent perspectives and selecting appropriate control action for goal driven agents. An example of power system...

  16. Enhancing Safety at Airline Operations Control Centre

    Directory of Open Access Journals (Sweden)

    Lukáš Řasa

    2015-04-01

    Full Text Available In recent years a new term of Safety Management System (SMS has been introduced into aviation legislation. This system is being adopted by airline operators. One of the groundbased actors of everyday operations is Operations Control Centre (OCC. The goal of this article has been to identify and assess risks and dangers which occur at OCC and create a template for OCC implementation into SMS.

  17. Improving the Transition of Earth Satellite Observations from Research to Operations

    Science.gov (United States)

    Goodman, Steven J.; Lapenta, William M.; Jedlovec, Gary J.

    2004-01-01

    There are significant gaps between the observations, models, and decision support tools that make use of new data. These challenges include: 1) Decreasing the time to incorporate new satellite data into operational forecast assimilation systems, 2) Blending in-situ and satellite observing systems to produce the most accurate and comprehensive data products and assessments, 3) Accelerating the transition from research to applications through national test beds, field campaigns, and pilot demonstrations, and 4) Developing the partnerships and organizational structures to effectively transition new technology into operations. At the Short-term Prediction Research and Transition (SPORT) Center in Huntsville, Alabama, a NASA-NOAA-University collaboration has been developed to accelerate the infusion of NASA Earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The SPoRT Center research focus is to improve forecasts through new observation capability and the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues such as convective initiation and 24-hr quantitative precipitation forecasting. The near real-time availability of high-resolution experimental products of the atmosphere, land, and ocean from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Infrared Spectroradiometer (AIRS), and lightning mapping systems provide an opportunity for science and algorithm risk reduction, and for application assessment prior to planned observations from the next generation of operational low Earth orbiting and geostationary Earth orbiting satellites. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future. The SPoRT Web page is at (http://www.ghcc.msfc.nasa.gov/sport).

  18. Control of the Soft X-ray Polychromator on the Solar Maximum Mission Satellite

    Science.gov (United States)

    Springer, L. A.; Levay, M.; Gilbreth, C. W.; Finch, M. L.; Bentley, R. D.; Firth, J. G.

    1981-01-01

    The Soft X-ray Polychromator on the Solar Maximum Mission Satellite consists of two largely independent instruments: the Flat Crystal Spectrometer, a highly collimated scanning spectrometer mounted on a raster platform, and the Bent Crystal Spectrometer, a broadly collimated spectrometer providing high time-resolution (128 ms) spectra for the study of rapidly evolving phenomena. Each instrument is controlled by a microcomputer system built around an RCA 1802 microprocessor. This paper presents a discussion of the motivation for using a microprocessor in this application, and the design concepts that were implemented. The effectiveness of the approach as seen after several months of operation will also be discussed.

  19. A comparing design of satellite attitude control system based on reaction wheel

    Institute of Scientific and Technical Information of China (English)

    CHENG Hao; GE Sheng-min; SHEN Yi

    2008-01-01

    The disturbance caused by the reaction wheel with a current controller greatly influences the accuracy and stability of the satellite attitude control system.To solve this problem,the idea of speed feedback compensation control reaction wheel is put forward.This paper introduces the comparison on design and performance of two satellite attitude control systems,which are separately based on the current control reaction wheel and the speed feedback compensation control reaction wheel.Analysis shows that the speed feedback compensation control flywheel system may effectively suppress the torque fluctuation.Simulation results indicate that the satellite attitude control system with the speed feedback compensation control flywheel has improved performance.

  20. Operational Assessment of Controller Complexity Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In today's operations, acceptable levels of controller workload are maintained by assigning sector capacities based on simple aircraft count and a capacity threshold...

  1. Attitude Control of Satellite With Pulse-Width Pulse- Frequency (PWPF Modulator Using Generalized Incremental Predictive Control

    Directory of Open Access Journals (Sweden)

    Ehsan Chegeni

    2014-09-01

    Full Text Available In this paper, we use generalized incremental predictive control (GIPC to stabilize attitude of satellite. We compare Generalized Predictive Control (GPC with GIPC algorithm and present that GIPC has better performance. The three-axis attitude control systems are activated in pulse mode. Consequently, a modulation of the torque command is compelling in order to avoid high non-linear control action. This work considers the Pulse-Width Pulse-Frequency modulator (PWPF is composed of a Schmitt trigger, a first order filter, and a feedback loop. PWPF modulator has several advantages over classical bang-bang controllers such as close to linear operation, high accuracy, and reduced propellant consumption

  2. Automatic Control of Freeboard and Turbine Operation

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter Bak; Friis-Madsen, Erik;

    The report deals with the modules for automatic control of freeboard and turbine operation on board the Wave dragon, Nissum Bredning (WD-NB) prototype, and covers what has been going on up to ultimo 2003.......The report deals with the modules for automatic control of freeboard and turbine operation on board the Wave dragon, Nissum Bredning (WD-NB) prototype, and covers what has been going on up to ultimo 2003....

  3. Tethered Satellites as an Enabling Platform for Operational Space Weather Monitoring Systems

    Science.gov (United States)

    Gilchrist, Brian E.; Krause, Linda Habash; Gallagher, Dennis Lee; Bilen, Sven Gunnar; Fuhrhop, Keith; Hoegy, Walt R.; Inderesan, Rohini; Johnson, Charles; Owens, Jerry Keith; Powers, Joseph; Voronka, Nestor; Williams, Scott

    2013-01-01

    Tethered satellites offer the potential to be an important enabling technology to support operational space weather monitoring systems. Space weather "nowcasting" and forecasting models rely on assimilation of near-real-time (NRT) space environment data to provide warnings for storm events and deleterious effects on the global societal infrastructure. Typically, these models are initialized by a climatological model to provide "most probable distributions" of environmental parameters as a function of time and space. The process of NRT data assimilation gently pulls the climate model closer toward the observed state (e.g., via Kalman smoothing) for nowcasting, and forecasting is achieved through a set of iterative semi-empirical physics-based forward-prediction calculations. Many challenges are associated with the development of an operational system, from the top-level architecture (e.g., the required space weather observatories to meet the spatial and temporal requirements of these models) down to the individual instruments capable of making the NRT measurements. This study focuses on the latter challenge: we present some examples of how tethered satellites (from 100s of m to 20 km) are uniquely suited to address certain shortfalls in our ability to measure critical environmental parameters necessary to drive these space weather models. Examples include long baseline electric field measurements, magnetized ionospheric conductivity measurements, and the ability to separate temporal from spatial irregularities in environmental parameters. Tethered satellite functional requirements are presented for two examples of space environment observables.

  4. Method of Time-Delay Calculating and Correcting to Control Spin-Stabilized Satellite Synchronously

    Institute of Scientific and Technical Information of China (English)

    YangTianshe; LiJisheng; HuangYongxuan

    2005-01-01

    The key to control Spin-Stabilized Satellites Synchronously is to determine the models for calculating and correcting of time-delay at the different situations. Based on the principle of Synchronous-Control mode, the methods of determining the models of calculating and correcting of time-delay are proposed. The methods have been proved to be effective in real satellite control engineering.

  5. Evaluation of SCaMPR Satellite QPEs for Operational Hydrologic Prediction

    Science.gov (United States)

    LEE, H.; Zhang, Y.; Seo, D.; Kitzmiller, D. H.; Kuligowski, R. J.; Corby, R.

    2011-12-01

    National Weather Service (NWS) River Forecast Centers (RFCs) use rain gauge or radar-gauge multi-sensor quantitative precipitation estimates (QPEs) as the primary rainfall input to their operational hydrologic models. In areas with poor radar and rain gauge coverage, satellite-based QPEs are a potential alternative. In this work, we evaluated the utility of satellite-based QPEs produced via the Self-Calibrating Multivariate Precipitation Retrieval (SCaMPR) algorithm for operational hydrologic modeling for a set of basins in Texas and Louisiana for the period of 2000-7. First, we assessed the relative accuracy of two sets of SCaMPR QPEs versus gauge-only QPE, with operational multi-sensor QPEs as the reference. One set used only operational polar orbiting satellite microwave input as the predictors, the other included Tropical Rainfall Measuring Mission (TRMM) rain rates in the calibration process. We then performed hydrologic simulations using these QPEs and evaluated the simulations. Results indicated that a) SCaMPR QPEs showed better/worse skill than the gauge-only QPEs in resolving heavy precipitation at 1-h/24-h time intervals in terms of Critical Success Index (CSI); b) SCaMPR QPEs underperformed gauge-only QPEs in simulating flood events; and c) ingesting TRMM rainfall rates helped enhance the hydrologic utility of SCaMPR QPE, by mitigating the positive bias of SCaMPR QPEs, elevating the detection rates of heavy rainfall, and improving the simulation of flood discharge. Our findings suggest that the superior performance of gauge-only QPEs versus SCaMPR in hydrologic simulations is tied to its better accuracy at 24-h scale. The implication of the scale dependence in the relative performance of SCaMPR QPEs to their potential hydrologic utility is discussed.

  6. CV controls from design to operation

    CERN Document Server

    Blanc, D

    2002-01-01

    The cooling and Ventilation (CV) group has emphasised the need to redefine its organisational structure at the end of 98. The main objective of this operation was to ensure the CV group to be more competitive and efficient through the growing tasks of the LHC projects. The main evolution given to this reorganisation is that the new structure is more project oriented and then operates on three distinct axes: Design, Work and Operation. Process control project management requires a complete and early interaction and participation of all the actors involved. This procedure to be efficient and constructive must be considered and performed not only during the design stage but along the project planning phases and must go beyond the completion work including the process control operation activity. The paper explains the present project management for process control. It describes the present constraints and gives suggestions to a different approach to these projects to improve performances and efficiency of a contr...

  7. Hydrate Control for Gas Storage Operations

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Savidge

    2008-10-31

    The overall objective of this project was to identify low cost hydrate control options to help mitigate and solve hydrate problems that occur in moderate and high pressure natural gas storage field operations. The study includes data on a number of flow configurations, fluids and control options that are common in natural gas storage field flow lines. The final phase of this work brings together data and experience from the hydrate flow test facility and multiple field and operator sources. It includes a compilation of basic information on operating conditions as well as candidate field separation options. Lastly the work is integrated with the work with the initial work to provide a comprehensive view of gas storage field hydrate control for field operations and storage field personnel.

  8. On Optimization Control Parameters in an Adaptive Error-Control Scheme in Satellite Networks

    Directory of Open Access Journals (Sweden)

    Ranko Vojinović

    2011-09-01

    Full Text Available This paper presents a method for optimization of control parameters of an adaptive GBN scheme in error-prone satellite channel. Method is based on the channel model with three state, where channel have the variable noise level.

  9. Attitude Control of a Satellite Simulator Using Reaction Wheels and a PID Controller

    Science.gov (United States)

    2010-03-01

    Rohe, and Welty in the development of AFIT’s second- generation satellite simulator, SimSat II [40]. Instead of building another dumbbell-style spherical...Nathan F. Welty . A Systems Engineering Approach to the Design of a Spacecraft Dynamics and Control Testbed. MS thesis, Air Force Institute of

  10. Security of Operation on CSR Control System

    Institute of Scientific and Technical Information of China (English)

    GouShizhe; QiaoWeimin; JingLan

    2003-01-01

    It is important to the security of operation on the CSR control system. In order to keep the CSR control system in security environment, the following work has been done. Firstly, it can be set up a domain service, and every important services can join in it, such as databasese rvices, front web services and every interactive operating browsers, and limited the browsers right by using policy of the domain. After this, the browsers can't modify the setting of the browser, and it can keep every computers and browsers in security by preventing some virus into each computer. The domain services of control system is shown in Fig.1.

  11. Operational protocols for controlling accelerator equipment

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, R.; Baribaud, G.; Benincasa, G.P.; Burla, P.; Casalegno, L.; Coudert, G.; Gelato, G.; Kuhn, H.K.; Saban, R.; Spinks, A. (European Organization for Nuclear Research, Geneva (Switzerland). LEP Div.)

    1990-08-01

    The equipment used to operate an accelerator is varied. However, the different devices may be divided into a limited number of classes for which operational protocols can be defined. Operational protocols permit: (i) a uniform operation, (ii) a clear definition of responsibility between the various specialists, (iii) independent development of programs and use of the most appropriate technology, (iv) the change of hardware and the transportability of software, and (v) the fabrication of devices by industry for general use. An operational protocol should be independent of any given control system and it must not be confused with a transmission protocol. As a first step, one defines an operational model of the device to be controlled. The model must represent a high-level description of the device as seen by the user. It will be characterized by a set of parameters and a set of rules. Although the particular requirements of specialists are not included in the operational protocol, allowances should be made for them. Emphasis will be placed on studies carried out on power converters and beam instrumentation. A general-purpose control message architecture is reported. (orig.).

  12. Operational protocols for controlling accelerator equipment

    Science.gov (United States)

    Bailey, R.; Baribaud, G.; Benincasa, G. P.; Burla, P.; Casalegno, L.; Coudert, G.; Gelato, G.; Kuhn, H. K.; Saban, R.; Spinks, A.

    1990-08-01

    The equipment used to operate an accelerator is varied. However, the different devices may be divided into a limited number of classes for which operational protocols can be defined. Operational protocols permit: (i) a uniform operation, (ii) a clear definition of responsibility between the various specialists, (iii) independent development of programs and use of the most appropriate technology, (iv) the change of hardware and the transportability of software, and (v) the fabrication of devices by industry for general use. An operational protocol should be independent of any given control system and it must not be confused with a transmission protocol. As a first step, one defines an operational model of the device to be controlled. The model must represent a high-level description of the device as seen by the user. It will be characterized by a set of parameters and a set of rules. Although the particular requirements of specialists are not included in the operational protocol, allowances should be made for them. Emphasis will be placed on studies carried out on power converters and beam instrumentation. A general-purpose control message architecture is reported.

  13. 4-D Cloud Water Content Fields Derived from Operational Satellite Data

    Science.gov (United States)

    Smith, William L., Jr.; Minnis, Patrick

    2010-01-01

    In order to improve operational safety and efficiency, the transportation industry, including aviation, has an urgent need for accurate diagnoses and predictions of clouds and associated weather conditions. Adverse weather accounts for 70% of all air traffic delays within the U.S. National Airspace System. The Federal Aviation Administration has determined that as much as two thirds of weather-related delays are potentially avoidable with better weather information and roughly 20% of all aviation accidents are weather related. Thus, it is recognized that an important factor in meeting the goals of the Next Generation Transportation System (NexGen) vision is the improved integration of weather information. The concept of a 4-D weather cube is being developed to address that need by integrating observed and forecasted weather information into a shared 4-D database, providing an integrated and nationally consistent weather picture for a variety of users and to support operational decision support systems. Weather analyses and forecasts derived using Numerical Weather Prediction (NWP) models are a critical tool that forecasters rely on for guidance and also an important element in current and future decision support systems. For example, the Rapid Update Cycle (RUC) and the recently implemented Rapid Refresh (RR) Weather Research and Forecast (WRF) models provide high frequency forecasts and are key elements of the FAA Aviation Weather Research Program. Because clouds play a crucial role in the dynamics and thermodynamics of the atmosphere, they must be adequately accounted for in NWP models. The RUC, for example, cycles at full resolution five cloud microphysical species (cloud water, cloud ice, rain, snow, and graupel) and has the capability of updating these fields from observations. In order to improve the models initial state and subsequent forecasts, cloud top altitude (or temperature, T(sub c)) derived from operational satellite data, surface observations of

  14. The Evolution of Operational Satellite Based Remote Sensing in Support of Weather Analysis, Nowcasting, and Hazard Mitigation

    Science.gov (United States)

    Hughes, B. K.

    2010-12-01

    The mission of the National Oceanic and Atmospheric Administration (NOAA) National Environmental Data Information Service (NESDIS) is to provide timely access to global environmental data from satellites and other sources to promote, protect, and enhance America’s economy, security, environment, and quality of life. To fulfill its responsibilities, NESDIS acquires and manages America’s operational environmental satellites, operates the NOAA National Data Centers, provides data and information services including Earth system monitoring, performs official assessments of the environment, and conducts related research. The Nation’s fleet of operational environmental satellites has proven to be very critical in the detection, analysis, and forecast of natural or man-made phenomena. These assets have provided for the protection of people and property while safeguarding the Nation’s commerce and enabling safe and effective military operations. This presentation will take the audience through the evolution of operational satellite based remote sensing in support of weather forecasting, nowcasting, warning operations, hazard detection and mitigation. From the very first experiments involving radiation budget to today’s fleet of Geostationary and Polar Orbiting satellites to tomorrow’s constellation of high resolution imagers and hyperspectral sounders, environmental satellites sustain key observations for current and future generations.

  15. IPO operational algorithm teams throughout the life cycle of NPOESS environmental satellites

    Science.gov (United States)

    Duda, James L.; Emch, Pamela G.

    2004-09-01

    The tri-agency Integrated Program Office (IPO) created Operational Algorithm Teams (OATs) in 1997 to provide scientific advice for managing the development and operation of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The scientific advice focuses on (1) assuring sound science in instrument and systems design in addition to (2) assuring development and implementation of sound scientific algorithms. This paper outlines the role of IPO operational algorithm teams from mission conception, through instrument design and development, algorithm science code development and conversion to operational code, data processing system implementation, calibration, validation, and, finally, operational data and products distribution to a range of users for weather, national security, and climate science. The composition of the algorithm science teams changes substantially as the sensors and algorithms are developed, tested, integrated, launched, become operational, and age on-orbit. The concept of leveraging our heritage scientists has proven successful with many tangible benefits to the government, the contractor teams, and, ultimately, the nation's taxpayers.

  16. Guidance and adaptive-robust attitude & orbit control of a small information satellite

    Science.gov (United States)

    Somov, Ye.; Butyrin, S.; Somov, S.; Somova, T.; Testoyedov, N.; Rayevsky, V.; Titov, G.; Yakimov, Ye.; Ovchinnikov, A.; Mathylenko, M.

    2017-01-01

    We consider a small information satellite which may be placed on an orbit with altitude from 600 up to 1000 km. The satellite attitude and orbit control system contains a strap-down inertial navigation system, cluster of four reaction wheels, magnetic driver and a correcting engine unit with eight electro-reaction engines. We study problems on design of algorithms for spatial guidance, in-flight identification and adaptive-robust control of the satellite motion on sun-synchronous orbit.

  17. Reusable Reentry Satellite (RRS) system design study. Phase B, appendix E: Attitude control system study

    Science.gov (United States)

    1991-01-01

    A study which consisted of a series of design analyses for an Attitude Control System (ACS) to be incorporated into the Re-usable Re-entry Satellite (RRS) was performed. The main thrust of the study was associated with defining the control laws and estimating the mass and power requirements of the ACS needed to meet the specified performance goals. The analyses concentrated on the different on-orbit control modes which start immediately after the separation of the RRS from the launch vehicle. The three distinct on-orbit modes considered for these analyses are as follows: (1) Mode 1 - A Gravity Gradient (GG) three-axis stabilized spacecraft with active magnetic control; (2) Mode 2 - A GG stabilized mode with a controlled yaw rotation rate ('rotisserie') using three-axis magnetic control and also incorporating a 10 N-m-s momentum wheel along the (Z) yaw axis; and (3) Mode 3 - A spin stabilized mode of operation with the spin about the pitch (Y) axis, incorporating a 20 N-m-s momentum wheel along the pitch (Y) axis and attitude control via thrusters. To investigate the capabilities of the different controllers in these various operational modes, a series of computer simulations and trade-off analyses have been made to evaluate the achievable performance levels, and the necessary mass and power requirements.

  18. Sentinel-1A - Launching the first satellite and launching the operational Copernicus programme

    Science.gov (United States)

    Aschbacher, Josef; Milagro Perez, Maria Pilar

    2014-05-01

    The first Copernicus satellite, Sentinel-1A, is prepared for launch in April 2014. It will provide continuous, systematic and highly reliable radar images of the Earth. Sentinel-1B will follow around 18 months later to increase observation frequency and establish an operational system. Sentinel-1 is designed to work in a pre-programmed conflict-free operation mode ensuring the reliability required by operational services and creating a consistent long-term data archive for applications based on long time series. This mission will ensure the continuation and improvement of SAR operational services and applications addressing primarily medium- to high-resolution applications through a main mode of operation that features both a wide swath (250 km) and high geometric (5 × 20 m) and radiometric resolution, allowing imaging of global landmasses, coastal zones, sea ice, polar areas, and shipping routes at high resolution. The Sentinel-1 main operational mode (Interferometric Wide Swath) will allow to have a complete coverage of the Earth in 6 days in the operational configuration when the two Sentinel-1 spacecraft will be in orbit simultaneously. High priority areas like Europe, Canada and some shipping routes will be covered almost daily. This high global observation frequency is unprecedented and cannot be reached with any other current radar mission. Envisat, for example, which was the 'workhorse' in this domain up to April 2012, reached global coverage every 35 days. Sentinel-1 data products will be made available systematically and free of charge to all users including institutional users, the general public, scientific and commercial users. The transition of the Copernicus programme from the development to operational phase will take place at about the same time when the first Sentinel-1 satellite will be launched. During the operational phase, funding of the programme will come from the European Union Multiannual Financial Framework (MFF) for the years 2014

  19. Precise Orbit Determination of BeiDou Satellites with Contributions from Chinese National Continuous Operating Reference Stations

    Directory of Open Access Journals (Sweden)

    Ming Chen

    2017-08-01

    Full Text Available The precise orbit determination (POD for BeiDou satellites is usually limited by the insufficient quantity and poor distribution of ground tracking stations. To cope with this problem, this study used the GPS and BeiDou joint POD method based on Chinese national continuous operating reference stations (CNCORS and IGS/MGEX stations. The results show that the 3D RMS of the differences of overlapping arcs is better than 22 cm for geostationary orbit (GEO satellites and better than 10 cm for inclined geosynchronous orbit (IGSO and medium earth orbit (MEO satellites. The radial RMS is better than 2 cm for all three types of BeiDou satellites. The results of satellite laser ranging (SLR residuals show that the RMS of the IGSO and MEO satellites is better than 5 cm, whereas the GEO satellite has a systematic bias. This study investigates the contributions of CNCORS to the POD of BeiDou satellites. The results show that after the incorporation of CNCORS, the precision of overlapping arcs of the GEO, IGSO, and MEO satellites is improved by 15.5%, 57.5%, and 5.3%, respectively. In accordance with the improvement in the precision of overlapping arcs, the accuracy of the IGSO and MEO satellites assessed by the SLR is improved by 30.1% and 4.8%, respectively. The computation results and analysis demonstrate that the inclusion of CNCORS yields the biggest contribution in the improvement of orbit accuracy for IGSO satellites, when compared to GEO satellites, while the orbit improvement for MEO satellites is the lowest due to their global coverage.

  20. Evaluation of Land Surface Temperature Operationally Retrieved from Korean Geostationary Satellite (COMS Data

    Directory of Open Access Journals (Sweden)

    A-Ra Cho

    2013-08-01

    Full Text Available We evaluated the precision of land surface temperature (LST operationally retrieved from the Korean multipurpose geostationary satellite, Communication, Ocean and Meteorological Satellite (COMS. The split-window (SW-type retrieval algorithm was developed through radiative transfer model simulations under various atmospheric profiles, satellite zenith angles, surface emissivity values and surface lapse rate conditions using Moderate Resolution Atmospheric Transmission version 4 (MODTRAN4. The estimation capabilities of the COMS SW (CSW LST algorithm were evaluated for various impacting factors, and the retrieval accuracy of COMS LST data was evaluated with collocated Moderate Resolution Imaging Spectroradiometer (MODIS LST data. The surface emissivity values for two SW channels were generated using a vegetation cover method. The CSW algorithm estimated the LST distribution reasonably well (averaged bias = 0.00 K, Root Mean Square Error (RMSE = 1.41 K, correlation coefficient = 0.99; however, the estimation capabilities of the CSW algorithm were significantly impacted by large brightness temperature differences and surface lapse rates. The CSW algorithm reproduced spatiotemporal variations of LST comparing well to MODIS LST data, irrespective of what month or time of day the data were collected from. The one-year evaluation results with MODIS LST data showed that the annual mean bias, RMSE and correlation coefficient for the CSW algorithm were −1.009 K, 2.613 K and 0.988, respectively.

  1. Utilization of Precipitation and Moisture Products Derived from Satellites to Support NOAA Operational Precipitation Forecasts

    Science.gov (United States)

    Ferraro, R.; Zhao, L.; Kuligowski, R. J.; Kusselson, S.; Ma, L.; Kidder, S. Q.; Forsythe, J. M.; Jones, A. S.; Ebert, E. E.; Valenti, E.

    2012-12-01

    NOAA/NESDIS operates a constellation of polar and geostationary orbiting satellites to support weather forecasts and to monitor the climate. Additionally, NOAA utilizes satellite assets from other U.S. agencies like NASA and the Department of Defense, as well as those from other nations with similar weather and climate responsibilities (i.e., EUMETSAT and JMA). Over the past two decades, through joint efforts between U.S. and international government researchers, academic partners, and private sector corporations, a series of "value added" products have been developed to better serve the needs of weather forecasters and to exploit the full potential of precipitation and moisture products generated from these satellites. In this presentation, we will focus on two of these products - Ensemble Tropical Rainfall Potential (eTRaP) and Blended Total Precipitable Water (bTPW) - and provide examples on how they contribute to hydrometeorological forecasts. In terms of passive microwave satellite products, TPW perhaps is most widely used to support real-time forecasting applications, as it accurately depicts tropospheric water vapor and its movement. In particular, it has proven to be extremely useful in determining the location, timing, and duration of "atmospheric rivers" which contribute to and sustain flooding events. A multi-sensor approach has been developed and implemented at NESDIS in which passive microwave estimates from multiple satellites and sensors are merged to create a seamless, bTPW product that is more efficient for forecasters to use. Additionally, this product is being enhanced for utilization for television weather forecasters. Examples will be shown to illustrate the roll of atmospheric rivers and contribution to flooding events, and how the bTPW product was used to improve the forecast of these events. Heavy rains associated with land falling tropical cyclones (TC) frequently trigger floods that cause millions of dollars of damage and tremendous loss

  2. Control through operators for quantum chemistry

    CERN Document Server

    Laurent, Philippe; Salomon, Julien; Turinici, Gabriel

    2012-01-01

    We consider the problem of operator identification in quantum control. The free Hamiltonian and the dipole moment are searched such that a given target state is reached at a given time. A local existence result is obtained. As a by-product, our works reveals necessary conditions on the laser field to make the identification feasible. In the last part of this work, some algorithms are proposed to compute effectively these operators.

  3. Three-Axis Satellite Attitude Control Based on Magnetic Torquing

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1995-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics.......Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics....

  4. Three-Axis Satellite Attitude Control Based on Magnetic Torquing

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1995-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics.......Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technilogical improvement of micro-electronics....

  5. Operation of Control Rod Driving Mechanism controller at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Gyu, Doo Seung; Woo, Lee Min; San, Choe Yeong; Kyoo, Kim Hyung [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    HANARO (High flux Advanced Neutron Application Reactor) achieved its first critical operation in 1995. Recently, there has been fast developments in the field of electronics. Many manufacturers of I and C components have disappeared or merged with the other companies. The suppliers of the control systems of the CRDM (Control Rod Driving Mechanism) at HANARO have disappeared. Therefore, we needed to change the control system of the CRDM since we cannot be provided with maintenance any longer. In this paper, we investigated the operation of the control system of the CRDM when the controller and motor driver are changed.

  6. Operational experience with the CEBAF control system

    Energy Technology Data Exchange (ETDEWEB)

    Hovater, C.; Chowdhary, M.; Karn, J.; Tiefenback, M.; Zeijts, J. van; Watson, W.

    1996-10-01

    The CEBAF accelerator at Thomas Jefferson National Accelerator Facility (Jefferson Lab) successfully began its experimental nuclear physics program in November of 1995 and has since surpassed predicted machine availability. Part of this success can be attributed to using the EPICS (Experimental Physics and Industrial Control System) control system toolkit. The CEBAF control system is one of the largest accelerator control system now operating. It controls approximately 338 SRF cavities, 2,300 magnets, 500 beam position monitors and other accelerator devices, such as gun hardware and other beam monitoring devices. All told, the system must be able to access over 125,000 database records. The system has been well received by both operators and the hardware designers. The EPICS utilities have made the task of troubleshooting systems easier. The graphical and test-based creation tools have allowed operators to custom build control screens. In addition, the ability to integrate EPICS with other software packages, such as Tcl/Tk, has allowed physicists to quickly prototype high-level application programs, and to provide GUI front ends for command line driven tools. Specific examples of the control system applications are presented in the areas of energy and orbit control, cavity tuning and accelerator tune up diagnostics.

  7. Derivation and evaluation of land surface temperature from the geostationary operational environmental satellite series

    Science.gov (United States)

    Fang, Li

    The Geostationary Operational Environmental Satellites (GOES) have been continuously monitoring the earth surface since 1970, providing valuable and intensive data from a very broad range of wavelengths, day and night. The National Oceanic and Atmospheric Administration's (NOAA's) National Environmental Satellite, Data, and Information Service (NESDIS) is currently operating GOES-15 and GOES-13. The design of the GOES series is now heading to the 4 th generation. GOES-R, as a representative of the new generation of the GOES series, is scheduled to be launched in 2015 with higher spatial and temporal resolution images and full-time soundings. These frequent observations provided by GOES Image make them attractive for deriving information on the diurnal land surface temperature (LST) cycle and diurnal temperature range (DTR). These parameters are of great value for research on the Earth's diurnal variability and climate change. Accurate derivation of satellite-based LSTs from thermal infrared data has long been an interesting and challenging research area. To better support the research on climate change, the generation of consistent GOES LST products for both GOES-East and GOES-West from operational dataset as well as historical archive is in great demand. The derivation of GOES LST products and the evaluation of proposed retrieval methods are two major objectives of this study. Literature relevant to satellite-based LST retrieval techniques was reviewed. Specifically, the evolution of two LST algorithm families and LST retrieval methods for geostationary satellites were summarized in this dissertation. Literature relevant to the evaluation of satellite-based LSTs was also reviewed. All the existing methods are a valuable reference to develop the GOES LST product. The primary objective of this dissertation is the development of models for deriving consistent GOES LSTs with high spatial and high temporal coverage. Proper LST retrieval algorithms were studied

  8. Quantum remote control Teleportation of unitary operations

    CERN Document Server

    Huelga, S F; Chefles, A; Plenio, M B

    2001-01-01

    We consider the implementation of an unknown arbitrary unitary operation U upon a distant quantum system. This teleportation of U can be viewed as a quantum remote control. We investigate the protocols which achieve this using local operations, classical communication and shared entanglement (LOCCSE). Lower bounds on the necessary entanglement and classical communication are determined using causality and the linearity of quantum mechanics. We examine in particular detail the resources required if the remote control is to be implemented as a classical black box. Under these circumstances, we prove that the required resources are, necessarily, those needed for implementation by bidirectional state teleportation.

  9. Failure-tolerant control for small agile satellites using single-gimbal control moment gyros and magnetic torquers

    Institute of Scientific and Technical Information of China (English)

    Tao Meng; Saburo Matunaga

    2012-01-01

    This paper focuses on the attitude control problem of small agile satellites using single-gimbal control moment gyros (CMG) and magnetic torquers (MTQ).CMGs are regarded as effective torque generators for agile satellites because of their torque amplification capability.However,they are vulnerable to failure due to their complex inner mechanism.In this paper,different failure cases of CMGs are analyzed.A flexible failure-tolerant control strategy is developed by automatically redistributing the required control torque among the operating CMGs and MTQs,with a variable limiter to accommodate the actuator dynamics changes introduced by CMG failures.The performances of maneuvers about different directions under different failure cases are also discussed and examined.Numerical simulations demonstrate that the proposed strategy maintains certain agility in the cases of one or two CMGs failing.Moreover,a survival strategy with only one CMG left is also verified.Both sun-pointing stabilization and earth-pointing stabilization can be achieved in this case,which fulfill some basic mission requirements.

  10. Satellite-Based Derivation of High-Resolution Forest Information Layers for Operational Forest Management

    Directory of Open Access Journals (Sweden)

    Johannes Stoffels

    2015-06-01

    Full Text Available A key factor for operational forest management and forest monitoring is the availability of up-to-date spatial information on the state of forest resources. Earth observation can provide valuable contributions to these information needs. The German federal state of Rhineland-Palatinate transferred its inherited forest information system to a new architecture that is better able to serve the needs of centralized inventory and planning services, down to the level of forest districts. During this process, a spatially adaptive classification approach was developed to derive high-resolution forest information layers (e.g., forest type, tree species distribution, development stages based on multi-temporal satellite data. This study covers the application of the developed approach to a regional scale (federal state level and the further adaptation of the design to meet the information needs of the state forest service. The results confirm that the operational requirements for mapping accuracy can, in principle, be fulfilled. However, the state-wide mapping experiment also revealed that the ability to meet the required level of accuracy is largely dependent on the availability of satellite observations within the optimum phenological time-windows.

  11. Mitigating Aviation Communication and Satellite Orbit Operations Surprises from Adverse Space Weather

    Science.gov (United States)

    Tobiska, W. Kent

    2008-01-01

    Adverse space weather affects operational activities in aviation and satellite systems. For example, large solar flares create highly variable enhanced neutral atmosphere and ionosphere electron density regions. These regions impact aviation communication frequencies as well as precision orbit determination. The natural space environment, with its dynamic space weather variability, is additionally changed by human activity. The increase in orbital debris in low Earth orbit (LEO), combined with lower atmosphere CO2 that rises into the lower thermosphere and causes increased cooling that results in increased debris lifetime, adds to the environmental hazards of navigating in near-Earth space. This is at a time when commercial space endeavors are posed to begin more missions to LEO during the rise of the solar activity cycle toward the next maximum (2012). For satellite and aviation operators, adverse space weather results in greater expenses for orbit management, more communication outages or aviation and ground-based high frequency radio used, and an inability to effectively plan missions or service customers with space-based communication, imagery, and data transferal during time-critical activities. Examples of some revenue-impacting conditions and solutions for mitigating adverse space weather are offered.

  12. Current and Future Impact Risks from Small Debris to Operational Satellites

    Science.gov (United States)

    Liou, Jer-Chyi; Kessler, Don

    2011-01-01

    The collision between Iridium 33 and Cosmos 2251 in 2009 signaled the potential onset of the collision cascade effect, commonly known as the "Kessler Syndrome", in the low Earth orbit (LEO) region. Recent numerical simulations have shown that the 10 cm and larger debris population in LEO will continue to increase even with a good implementation of the commonly-adopted mitigation measures. This increase is driven by collisions involving large and massive intacts, i.e., rocket bodies and spacecraft. Therefore, active debris removal (ADR) of large and massive intacts with high collision probabilities has been argued as a direct and effective means to remediate the environment in LEO. The major risk for operational satellites in the environment, however, comes from impacts with debris just above the threshold of the protection shields. In general, these are debris in the millimeter to centimeter size regime. Although impacts by these objects are insufficient to lead to catastrophic breakup of the entire vehicle, the damage is certainly severe enough to cause critical failure of the key instruments or the entire payload. The focus of this paper is to estimate the impact risks from 5 mm and 1 cm debris to active payloads in LEO (1) in the current environment and (2) in the future environment based on different projection scenarios, including ADR. The goal of the study is to quantify the benefits of ADR in reducing debris impact risks to operational satellites.

  13. Quality control methods for KOOS operational sea surface temperature products

    Institute of Scientific and Technical Information of China (English)

    YANG Chansu; KIM Sunhwa

    2016-01-01

    Sea surface temperature SST obtained from the initial version of the Korea Operational Oceanographic System (KOOS) SST satellite have low accuracy during summer and daytime. This is attributed to the diurnal warming effect. Error estimation of SST data must be carried out to use the real-time forecasting numerical model of the KOOS. This study suggests two quality control methods for the KOOS SST system. To minimize the diurnal warming effect, SSTs of areas where wind speed is higher than 5 m/s were used. Depending on the wind threshold value, KOOS SST data for August 2014 were reduced by 0.15°C. Errors in SST data are considered to be a combination of random, sampling, and bias errors. To estimate bias error, the standard deviation of bias between KOOS SSTs and climatology SSTs were used. KOOS SST data yielded an analysis error standard deviation value similar to OSTIA and NOAA NCDC (OISST) data. The KOOS SST shows lower random and sampling errors with increasing number of observations using six satellite datasets. In further studies, the proposed quality control methods for the KOOS SST system will be applied through more long-term case studies and comparisons with other SST systems.

  14. Operating and Managing a Backup Control Center

    Science.gov (United States)

    Marsh, Angela L.; Pirani, Joseph L.; Bornas, Nicholas

    2010-01-01

    Due to the criticality of continuous mission operations, some control centers must plan for alternate locations in the event an emergency shuts down the primary control center. Johnson Space Center (JSC) in Houston, Texas is the Mission Control Center (MCC) for the International Space Station (ISS). Due to Houston s proximity to the Gulf of Mexico, JSC is prone to threats from hurricanes which could cause flooding, wind damage, and electrical outages to the buildings supporting the MCC. Marshall Space Flight Center (MSFC) has the capability to be the Backup Control Center for the ISS if the situation is needed. While the MSFC Huntsville Operations Support Center (HOSC) does house the BCC, the prime customer and operator of the ISS is still the JSC flight operations team. To satisfy the customer and maintain continuous mission operations, the BCC has critical infrastructure that hosts ISS ground systems and flight operations equipment that mirrors the prime mission control facility. However, a complete duplicate of Mission Control Center in another remote location is very expensive to recreate. The HOSC has infrastructure and services that MCC utilized for its backup control center to reduce the costs of a somewhat redundant service. While labor talents are equivalent, experiences are not. Certain operations are maintained in a redundant mode, while others are simply maintained as single string with adequate sparing levels of equipment. Personnel at the BCC facility must be trained and certified to an adequate level on primary MCC systems. Negotiations with the customer were done to match requirements with existing capabilities, and to prioritize resources for appropriate level of service. Because some of these systems are shared, an activation of the backup control center will cause a suspension of scheduled HOSC activities that may share resources needed by the BCC. For example, the MCC is monitoring a hurricane in the Gulf of Mexico. As the threat to MCC

  15. Sentinel Convoy: Synergetic Earth Observation with Satellites Flying in Formation with European Operational Missions

    Science.gov (United States)

    Regan, Amanda; Silvestrin, Pierluigi; Fernandez, Diego

    2016-08-01

    The successful launch of Sentinel-1A, Sentinel-1B, Sentinel-2A and Sentinel-3A signify the beginning of the dedicated space segment for the Copernicus Programme, which is the result of the partnership between the European Commission (EC) and the European Space Agency (ESA). These Sentinels are the first of a long-term operational series of Earth Observation (EO) satellites to be launched by Europe that will complement the already well-established series of meteorological missions.For the first time, these missions will provide a continuous and long term European capability for systematic observations of the Earth surface, its oceans and atmosphere to unprecedented accuracies, resolutions, and temporal coverage. If additional cost- effective missions could be flown together with these operational missions (including operational meteorological satellite series such as MetOp (Second Generation - SG) then the possibilities for meeting new Earth science and application objectives could be far- reaching e.g. fulfilling observational gaps, synergistic measurements of Earth system processes, etc. To explore this potential, the ESA initiated three exploratory paper studies (known as the EO-Convoy studies). The aim of these studies is two fold: Firstly, to identify scientific and operational objectives and needs that would benefit from additional in-orbit support. Secondly, to identify and develop a number of cost- effective mission concepts that would meet these objectives and needs. Each EO Convoy study is dedicated to a specific theme, namely: Study 1 - Ocean and Ice Applications, Study 2 - Land Applications and Study 3 - Atmospheric Applications.This paper will present the results of the EO-Convoy studies including an overview of the user needs and derived convoy concept descriptions. This paper shall focus on the resulting science benefits. Example convoy concepts to be presented include a passive C-band SAR flying with Sentinel-1 and possible free flying thermal

  16. Operator approach to linear control systems

    CERN Document Server

    Cheremensky, A

    1996-01-01

    Within the framework of the optimization problem for linear control systems with quadratic performance index (LQP), the operator approach allows the construction of a systems theory including a number of particular infinite-dimensional optimization problems with hardly visible concreteness. This approach yields interesting interpretations of these problems and more effective feedback design methods. This book is unique in its emphasis on developing methods for solving a sufficiently general LQP. Although this is complex material, the theory developed here is built on transparent and relatively simple principles, and readers with less experience in the field of operator theory will find enough material to give them a good overview of the current state of LQP theory and its applications. Audience: Graduate students and researchers in the fields of mathematical systems theory, operator theory, cybernetics, and control systems.

  17. Operator versus computer control of adaptive automation

    Science.gov (United States)

    Hilburn, Brian; Molloy, Robert; Wong, Dick; Parasuraman, Raja

    1993-01-01

    Adaptive automation refers to real-time allocation of functions between the human operator and automated subsystems. The article reports the results of a series of experiments whose aim is to examine the effects of adaptive automation on operator performance during multi-task flight simulation, and to provide an empirical basis for evaluations of different forms of adaptive logic. The combined results of these studies suggest several things. First, it appears that either excessively long, or excessively short, adaptation cycles can limit the effectiveness of adaptive automation in enhancing operator performance of both primary flight and monitoring tasks. Second, occasional brief reversions to manual control can counter some of the monitoring inefficiency typically associated with long cycle automation, and further, that benefits of such reversions can be sustained for some time after return to automated control. Third, no evidence was found that the benefits of such reversions depend on the adaptive logic by which long-cycle adaptive switches are triggered.

  18. Error control techniques for satellite and space communications

    Science.gov (United States)

    Costello, Daniel J., Jr.

    1989-01-01

    Two aspects of the work for NASA are examined: the construction of multi-dimensional phase modulation trellis codes and a performance analysis of these codes. A complete list is contained of all the best trellis codes for use with phase modulation. LxMPSK signal constellations are included for M = 4, 8, and 16 and L = 1, 2, 3, and 4. Spectral efficiencies range from 1 bit/channel symbol (equivalent to rate 1/2 coded QPSK) to 3.75 bits/channel symbol (equivalent to 15/16 coded 16-PSK). The parity check polynomials, rotational invariance properties, free distance, path multiplicities, and coding gains are given for all codes. These codes are considered to be the best candidates for implementation of a high speed decoder for satellite transmission. The design of a hardware decoder for one of these codes, viz., the 16-state 3x8-PSK code with free distance 4.0 and coding gain 3.75 dB is discussed. An exhaustive simulation study of the multi-dimensional phase modulation trellis codes is contained. This study was motivated by the fact that coding gains quoted for almost all codes found in literature are in fact only asymptotic coding gains, i.e., the coding gain at very high signal to noise ratios (SNRs) or very low BER. These asymptotic coding gains can be obtained directly from a knowledge of the free distance of the code. On the other hand, real coding gains at BERs in the range of 10(exp -2) to 10(exp -6), where these codes are most likely to operate in a concatenated system, must be done by simulation.

  19. Generation of high resolution sea surface temperature using multi-satellite data for operational oceanography

    Institute of Scientific and Technical Information of China (English)

    YANG Chan-Su; KIM Sun-Hwa; OUCHI Kazuo; BACK Ji-Hun

    2015-01-01

    In the present article, we introduce a high resolution sea surface temperature (SST) product generated daily by Korea Institute of Ocean Science and Technology (KIOST). The SST product is comprised of four sets of data including eight-hour and daily average SST data of 1 km resolution, and is based on the four infrared (IR) satellite SST data acquired by advanced very high resolution radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS), Multifunctional Transport Satellites-2 (MTSAT-2) Imager and Meteorological Imager (MI), two microwave radiometer SSTs acquired by Advanced Microwave Scanning Radiometer 2 (AMSR2), and WindSAT within-situ temperature data. These input satellite andin-situ SST data are merged by using the optimal interpolation (OI) algorithm. The root-mean-square-errors (RMSEs) of satellite andin-situ data are used as a weighting value in the OI algorithm. As a pilot product, four SST data sets were generated daily from January to December 2013. In the comparison between the SSTs measured by moored buoys and the daily mean KIOST SSTs, the estimated RMSE was 0.71°C and the bias value was –0.08°C. The largest RMSE and bias were 0.86 and –0.26°C respectively, observed at a buoy site in the boundary region of warm and cold waters with increased physical variability in the Sea of Japan/East Sea. Other site near the coasts shows a lower RMSE value of 0.60°C than those at the open waters. To investigate the spatial distributions of SST, the Group for High Resolution Sea Surface Temperature (GHRSST) product was used in the comparison of temperature gradients, and it was shown that the KIOST SST product represents well the water mass structures around the Korean Peninsula. The KIOST SST product generated from both satellite and buoy data is expected to make substantial contribution to the Korea Operational Oceanographic System (KOOS) as an input parameter for data assimilation.

  20. Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

    Science.gov (United States)

    TayyebTaher, M.; Esmaeilzadeh, S. Majid

    2017-07-01

    This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

  1. Development and Validation of the On-Board Control Procedures Subsystem for the Herschel and Planck Satellites

    Science.gov (United States)

    Ferraguto, M.; Wittrock, T.; Barrenscheen, M.; Paakko, M.; Sipinen, V.; Pelttari, L.

    2009-05-01

    The On-Board Control Procedures (OBCP) subsystem of Herschel and Planck Satellites' Central Data Management Unit (CDMU) Application SW (ASW) provides means to control the spacecraft through small script-like programs written in a specific language called On-board Command Language (OCL). The implementation for Herschel and Planck satellites is an adaptation from previous experiences on instruments like Rosetta/OSIRIS, Venus Express/VMC and Dawn/FC, but it had also been adapted successfully for the GOCE satellite already. A thorough validation campaign has been conducted to qualify the H&P SW implementation for flight. The purpose of having on-board control procedures is to allow the ground operators to be able to prepare and up-link complex operations sequences (more complex than simple sequences of mission time-line telecommands) to be executed on-board during the mission operational phase. This is possible because the OBCPs run in a quite separate subsystem, so the creation of a new procedure does not require modification, uplink and re-validation of the whole on-board software. The OBCP subsystem allows these control procedures to be developed, tested on ground, and executed on the spacecraft.

  2. Miniature Reaction Wheel for Small Satellite Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of this project is to design, develop, demonstrate, and deliver a miniature, high torque, low-vibration reaction wheel for use on small satellites....

  3. Use of charging control guidelines for geosynchronous satellite design studies

    Science.gov (United States)

    Steves, N. J.

    1980-01-01

    Several of the principle guidelines from the Spacecraft Charging Design Guidelines Handbook are presented with illustrative examples. Use of the geomagnetic substorm specification to qualify satellite designs, the evaluation of satellite designs by using analytical modelling techniques, the use of selected materials and coatings to minimize charging, the tying of all conducting elements to a common ground, and the use of electrical filtering to protect circuits from discharge induced upsets are discussed. Discharge criteria and SCATHA data are excluded.

  4. Satellite de-orbiting via controlled solar radiation pressure

    Science.gov (United States)

    Deienno, Rogerio; Sanchez, Diogo Merguizo; de Almeida Prado, Antonio Fernando Bertachini; Smirnov, Georgi

    2016-06-01

    The goal of the present research was to study the use of solar radiation pressure to place a satellite in an orbit that makes it to re-enter the atmosphere of the Earth. This phase of the mission is usual, since the orbital space around the Earth is crowded and all satellites have to be discarded after the end of their lifetimes. The technique proposed here is based on a device that can increase and decrease the area-to-mass ratio of the satellite when it is intended to reduce its altitude until a re-entry point is reached. Equations that predict the evolution of the eccentricity and semi-major axis of the orbit of the satellite are derived and can be used to allow the evaluation of the time required for the decay of the satellite. Numerical simulations are made, and they show the time required for the decay as a function of the area-to-mass ratio and the evolution of the most important orbital elements. The results show maps that indicate regions of fast decays as a function of the area-to-mass ratio and the initial inclination of the orbit of the satellite. They also confirmed the applicability of the equations derived here. The numerical results showed the role played by the evection and the Sun-synchronous resonances in the de-orbiting time.

  5. A close examination of under-actuated attitude control subsystem design for future satellite missions' life extension

    Science.gov (United States)

    Lam, Quang M.; Barkana, Itzhak

    2014-12-01

    Satellite mission life, maintained and prolonged beyond its typical norm of their expectancy, are primarily dictated by the state of health of its Reaction Wheel Assembly (RWA), especially for commercial GEO satellites since torquer bars are no longer applicable while thruster assistant is unacceptable due to pointing accuracy impact during jet firing. The RWA is the primary set of actuators (as compared to thrusters for orbit maintenance and maneuvering) mainly responsible for the satellite mission for accurately and precisely pointing its payloads to the right targets to conduct its mission operations. The RWA consisting of either a set of four in pyramid or three in orthogonal is the primary set of actuators to allow the satellite to achieve accurate and precise pointing of the satellite payloads towards the desired targets. Future space missions will be required to achieve much longer lives and are currently perceived by the GEO satellite community as an "expected norm" of 20 years or longer. Driven by customers' demands/goals and competitive market have challenged Attitude Control Subsystems (ACS) engineers to develop better ACS algorithms to address such an emerging need. There are two main directions to design satellite's under-actuated control subsystem: (1) Attitude Feedback with Zero Momentum Principle and (2) Attitude Control by Angular Velocity Tracking via Small Time Local Controllability concept. Successful applications of these control laws have been largely demonstrated via simulation for the rest to rest case. Limited accuracy and oscillatory behaviors are observed in three axes for non-zero wheel momentum while realistic loss of a wheel scenario (i.e., fully actuated to under-actuated) has not been closely examined! This study revisits the under-actuated control design with detailed set ups of multiple scenarios reflecting real life operating conditions which have put current under-actuated control laws mentioned earlier into a re-evaluation mode

  6. An operator's views on Fermilab's control system

    Science.gov (United States)

    Baddorf, Debra S.

    1986-06-01

    A Fermilab accelerator operator presents views and personal opinions on the control system there. The paper covers features contributing to ease of use and comprehension, as well as a few things that could be improved. Included are such hardware as the trackball and interrupt button, the touch sensitive TV screen, the color Lexidata display, and black and white and color hardcopy capabilities. It also covers the software such as the generic parameter page, the generic plot package, and prepared displays. The alarm system is discussed from an operations standpoint, and also the datalogging system.

  7. Performance of TCP Vegas, Bic and Reno Congestion Control Algorithms on Iridium Satellite Constellations

    Directory of Open Access Journals (Sweden)

    M.Nirmala

    2012-11-01

    Full Text Available Satellite networking is different from wired or wireless networks. The behavior and the performance of TCP/IP in normal wireless network as well as in wired network are different from one another. The TCP/IP protocol was not designed to perform well over high-latency or noisy channels so its performance over satellite networks are totally different. Each satellite networks/constellations have different properties. The deployment height, motion, direction, link capacity – all differ from one satellite constellations to another. So, certainly the behavior of TCP/IP will considerably differ from one satellite constellations than another.The Performance of three different TCP Congestion algorithms, Vegas, Reno and Bic are taken for evaluation on the simulated satellite network Iridium and the performance of the three algorithms under the satellites constellation is measured using suitable metrics. It is observed that, irrespective of the high end to end delay, the behavior of TCP/IP under Satellite network is somewhat resembling a high latency wired network. TCP under satellite network is not like that of a mobile ADHOC network. The observation resulted that the overall performance of Vegas was good in Iridium constellations. These reasons should be explored for designing a better congestion control algorithm exclusively for Satellite Networks.

  8. Spaceborne observations of a changing Earth - Contribution from ESÁ s operating and approved satellite missions.

    Science.gov (United States)

    Johannessen, J. A.

    2009-04-01

    The overall vision for ESÁs Earth Observation activities is to play a central role in developing the global capability to understand planet Earth, predict changes, and mitigate negative effects of global change on its populations. Since Earth observation from space first became possible more than forty years ago, it has become central to monitoring and understanding how the dynamics of the Earth System work. The greatest progress has been in meteorology, where space-based observations have become indispensable, but it is now also progressively penetrating many of the fields making up Earth sciences. Exploiting Earth observation from space presents major multidisciplinary challenges to the researches working in the Earth sciences, to the technologists who build the state-of-the-art sensors, and to the scientists interpreting measurements made of processes occurring on or within the Earth's surface and in its atmosphere. The scientific community has shown considerable imagination in rising to these challenges, and in exploiting the latest technological developments to measure from space the complex processes and interactions that occur in the Earth System. In parallel, there has been significant progress in developing computer models that represent the many processes that make up the Earth System, and the interactions and feedback between them. Success in developing this holistic view is inextricably linked to the data provided by Earth Observation systems. Satellites provide the fundamental, consistent, regular and global measurements needed to drive, parameterise, test and improve those Earth System models. These developments, together with changes in society's awareness of the need for information on a changing world, have repetitively supported the decisions on how ESA can best focus its resources, and those of the European community that it serves, in order to address critical issues in Earth System science. Moreover, it is a fact that many operational

  9. Active-passive integrated vibration control for control moment gyros and its application to satellites

    Science.gov (United States)

    Zhang, Yao; Zang, Yue; Li, Mou; Wang, Youyi; Li, Wenbo

    2017-04-01

    The strategy of active-passive integrated vibration control on the truss enveloping control moment gyroscopes (CMGs) is presented and its characteristics of time domain and frequency domain are analyzed. Truss enveloping CMGs contains pyramid-type CMGs, which are enveloped by multiple struts. These struts can be employed to realize the active-passive integrated vibration control. In addition, the struts of the trusses can maintain the working space of CMGs. Firstly, the disturbance characteristics of CMGs are analyzed considering static and dynamic imbalances of the CMG's rotor; then, an active-passive integrated vibration isolation truss structure is developed based on its characteristics. This structure can restrain the CMG vibration as much as possible and reduce its influence on the photographic quality of optical payloads. Next, the dynamic model of the active-passive vibration isolation truss structure is established. The frequency domain analysis of this model shows that the active-passive integrated vibration control method can restrain the high-frequency vibration and also improve the characteristics of low-frequency vibration. Finally, the dynamic model for the whole satellite is built with this type of CMGs. The time domain simulations of satellite attitude control verify the attitude control improvements resulting from the CMGs vibration control strategy.

  10. ESTABLISHMENT OF SATELLITE FORMATION WITH INITIAL UNCERTAINTY BY CONTROL LYAPUNOV FUNCTION APPROACH

    Directory of Open Access Journals (Sweden)

    M. Navabi

    2012-03-01

    Full Text Available In recent years, dynamics and control of satellite formation flying have been active areas of research. From the mission planning perspective, three main areas namely formation establishment, maintenance and reconfiguration have been discussed. In this paper, a study of formation establishment under initial uncertainty is presented. In this regard, dynamics of low Earth orbit satellite formation is discussed. Control Lyapunov function approach is adopted to bring a deputy satellite, with perturbed initial conditions into formation with a chief satellite. In order to take account of the initial orbit insertion error, uncertainty in initial conditions of the deputy satellite is considered. For a case study, a relatively small formation is adopted, with air-launched Pegasus as the launch vehicle. For several initial conditions, control function and required time to achieve a given mission accuracy are determined, and results are provided as illustration.

  11. New insights into the epigenetic control of satellite cells

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Epigenetics finely tunes gene expression at a functionallevel without modifying the DNA sequence, therebycontributing to the complexity of genomic regulation.Satellite cells (SCs) are adult muscle stem cells thatare important for skeletal post-natal muscle growth,homeostasis and repair. The understanding of theepigenome of SCs at different stages and of themultiple layers of the post-transcriptional regulationof gene expression is constantly expanding. Dynamicinteractions between different epigenetic mechanismsregulate the appropriate timing of muscle-specific geneexpression and influence the lineage fate of SCs. Inthis review, we report and discuss the recent literatureabout the epigenetic control of SCs during the myogenicprocess from activation to proliferation and from theircommitment to a muscle cell fate to their differentiationand fusion to myotubes. We describe how the coordinatedactivities of the histone methyltransferasefamilies Polycomb group (PcG), which represses theexpression of developmentally regulated genes, andTrithorax group, which antagonizes the repressive activityof the PcG, regulate myogenesis by restricting geneexpression in a time-dependent manner during eachstep of the process. We discuss how histone acetylationand deacetylation occurs in specific loci throughoutSC differentiation to enable the time-dependent transcriptionof specific genes. Moreover, we describe themultiple roles of microRNA, an additional epigeneticmechanism, in regulating gene expression in SCs, byrepressing or enhancing gene transcription or translationduring each step of myogenesis. The importance ofthese epigenetic pathways in modulating SC activationand differentiation renders them as promising targetsfor disease interventions. Understanding the mostrecent findings regarding the epigenetic mechanismsthat regulate SC behavior is useful from the perspectiveof pharmacological manipulation for improving muscleregeneration and for promoting muscle homeostasisunder

  12. Tethered Satellites as Enabling Platforms for an Operational Space Weather Monitoring System

    Science.gov (United States)

    Krause, L. Habash; Gilchrist, B. E.; Bilen, S.; Owens, J.; Voronka, N.; Furhop, K.

    2013-01-01

    Space weather nowcasting and forecasting models require assimilation of near-real time (NRT) space environment data to improve the precision and accuracy of operational products. Typically, these models begin with a climatological model to provide "most probable distributions" of environmental parameters as a function of time and space. The process of NRT data assimilation gently pulls the climate model closer toward the observed state (e.g. via Kalman smoothing) for nowcasting, and forecasting is achieved through a set of iterative physics-based forward-prediction calculations. The issue of required space weather observatories to meet the spatial and temporal requirements of these models is a complex one, and we do not address that with this poster. Instead, we present some examples of how tethered satellites can be used to address the shortfalls in our ability to measure critical environmental parameters necessary to drive these space weather models. Examples include very long baseline electric field measurements, magnetized ionospheric conductivity measurements, and the ability to separate temporal from spatial irregularities in environmental parameters. Tethered satellite functional requirements will be presented for each space weather parameter considered in this study.

  13. Teachers guide for building and operating weather satellite ground stations for high school science

    Science.gov (United States)

    Summers, R. J.; Gotwald, T.

    1981-01-01

    A number of colleges and universities are operating APT direct readout stations. However, high school science teachers have often failed to realize the potential of meteorological satellites and their products as unique instructional tools. The ability to receive daily pictures from these satellites offers exciting opportunities for secondary school teachers and students to assemble the electronic hardware and to view real time pictures of Earth from outer space. The station and pictures can be used in the classroom to develop an approach to science teaching that could span many scientific disciplines and offer many opportunities for student research and participation in scientific processes. This can be accomplished with relatively small expenditures of funds for equipment. In most schools some of the equipment may already be available. Others can be constructed by teachers and/or students. Yet another source might be the purchase of used equipment from industry or through the government surplus channels. The information necessary for individuals unfamiliar with these systems to construct a direct readout for receiving real time APT photographs on a daily basis in the classroom is presented.

  14. Intelligent Control and Operation of Distribution System

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad

    to be implemented with the existing technology. One of the potential alternatives is to intelligently control the electrical loads to make them follow the intermittent generation. This not only enables the end consumers to get reliable and cheap electricity but also enables the utility to prevent huge investment...... in counterpart. Therefore, the theoretical foundation of this research work is based on a paradigm shift in ‘generation following demand’ to ‘demand following generation’ scenario. The primary aim of this research work is to develop intelligent control architecture, control strategies, and an adaptive protection...... in this direction but also benefit distribution system operators in the planning and development of the distribution network. The major contributions of this work are described in the following four stages: In the first stage, an intelligent Demand Response (DR) control architecture is developed for coordinating...

  15. Quadrocopter Control Design and Flight Operation

    Science.gov (United States)

    Karwoski, Katherine

    2011-01-01

    A limiting factor in control system design and analysis for spacecraft is the inability to physically test new algorithms quickly and cheaply. Test flights of space vehicles are costly and take much preparation. As such, EV41 recently acquired a small research quadrocopter that has the ability to be a test bed for new control systems. This project focused on learning how to operate, fly, and maintain the quadrocopter, as well as developing and testing protocols for its use. In parallel to this effort, developing a model in Simulink facilitated the design and analysis of simple control systems for the quadrocopter. Software provided by the manufacturer enabled testing of the Simulink control system on the vehicle.

  16. OPTIMAL OPERATIONAL CONTROL OF INTERCEPTOR SEWER SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper, a mathematical model was built up to solve the problem of optimal operational control by analysing the factors on an interceptor sewer system and a Fortran program was produced for this model. This paper shows that the optimal control states can be determined by working out the optimal flow rates by means of Linear Programming (LP). The result is very sensitive to interception points and the concentration weight coefficients over time. The result further highlights some practical applications for the existing sewer systems or the sewer systems under design.

  17. Spacecraft flight control system design selection process for a geostationary communication satellite

    Science.gov (United States)

    Barret, C.

    1992-01-01

    The Earth's first artificial satellite, Sputnik 1, slowly tumbled in orbit. The first U.S. satellite, Explorer 1, also tumbled out of control. Now, as we launch the Mars observer and the Cassini spacecraft, stability and control have become higher priorities. The flight control system design selection process is reviewed using as an example a geostationary communication satellite which is to have a life expectancy of 10 to 14 years. Disturbance torques including aerodynamic, magnetic, gravity gradient, solar, micrometeorite, debris, collision, and internal torques are assessed to quantify the disturbance environment so that the required compensating torque can be determined. Then control torque options, including passive versus active, momentum control, bias momentum, spin stabilization, dual spin, gravity gradient, magnetic, reaction wheels, control moment gyros, nutation dampers, inertia augmentation techniques, three-axis control, reactions control system (RCS), and RCS sizing, are considered. A flight control system design is then selected and preliminary stability criteria are met by the control gains selection.

  18. Four Step to Control in the Use of Satellite Format Simulation%四层梯阶控制在卫星编队的应用仿真

    Institute of Scientific and Technical Information of China (English)

    刘猛; 冯永新; 范增

    2012-01-01

    研究了四层阶梯控制在卫星编队的控制问题及仿真.利用卫星相对运动的线性方程组和轨道机动算法的基础上,结合卫星任务规划、行为决策、行为规划和操作控制的四层阶梯卫星编队结构,从而建立建立卫星编队绕飞半径的滤波控制.仿真结果表明了四层阶梯控制在卫星编队在上对运动过程中,缩小卫星之间相对距离变换范围,增强卫星编队的稳定性.%The satellite format control and emulation by four steps to control are studied in the thesis. Based on the research of the relative equations of linear equations and track the algorithms, combining satellite mission planning,decision-making,behavior planning and operation control of four step satellite formation structure, leading to the establishment of satellite formation flying around the radius of the filter control. The simulation results show that the cfour step control in satellite formation in relative motion process,reduce the satellite relative distance between the trasformation range,enhance the stability of satellite formation flying.

  19. Testing command and control of the satellites in formation flight

    Science.gov (United States)

    Gheorghe, Popan; Gheorghe, Gh. Ion; Gabriel, Todoran

    2013-10-01

    The topics covered in the paper are mechatronic systems for determining the distance between the satellites and the design of the displacement system on air cushion table for satellites testing. INCDMTM has the capability to approach the collaboration within European Programms (ESA) of human exploration of outer space through mechatronic systems and accessories for telescopes, mechatronics systems used by the launchers, sensors and mechatronic systems for the robotic exploration programs of atmosphere and Mars. This research has a strong development component of industrial competitiveness many of the results of space research have direct applicability in industrial fabrication.

  20. Autonomous Satellite Command and Control Through the World Wide Web. Phase 3

    Science.gov (United States)

    Cantwell, Brian; Twiggs, Robert

    1998-01-01

    The Automated Space System Experimental Testbed (ASSET) system is a simple yet comprehensive real-world operations network being developed. Phase 3 of the ASSET Project was January-December 1997 and is the subject of this report. This phase permitted SSDL and its project partners to expand the ASSET system in a variety of ways. These added capabilities included the advancement of ground station capabilities, the adaptation of spacecraft on-board software, and the expansion of capabilities of the ASSET management algorithms. Specific goals of Phase 3 were: (1) Extend Web-based goal-level commanding for both the payload PI and the spacecraft engineer. (2) Support prioritized handling of multiple (PIs) Principle Investigators as well as associated payload experimenters. (3) Expand the number and types of experiments supported by the ASSET system and its associated spacecraft. (4) Implement more advanced resource management, modeling and fault management capabilities that integrate the space and ground segments of the space system hardware. (5) Implement a beacon monitoring test. (6) Implement an experimental blackboard controller for space system management. (7) Further define typical ground station developments required for Internet-based remote control and for full system automation of the PI-to-spacecraft link. Each of those goals are examined. Significant sections of this report were also published as a conference paper. Several publications produced in support of this grant are included as attachments. Titles include: 1) Experimental Initiatives in Space System Operations; 2) The ASSET Client Interface: Balancing High Level Specification with Low Level Control; 3) Specifying Spacecraft Operations At The Product/Service Level; 4) The Design of a Highly Configurable, Reusable Operating System for Testbed Satellites; 5) Automated Health Operations For The Sapphire Spacecraft; 6) Engineering Data Summaries for Space Missions; and 7) Experiments In Automated Health

  1. Optimizing operational water management with soil moisture data from Sentinel-1 satellites

    Science.gov (United States)

    Pezij, Michiel; Augustijn, Denie; Hendriks, Dimmie; Hulscher, Suzanne

    2016-04-01

    In the Netherlands, regional water authorities are responsible for management and maintenance of regional water bodies. Due to socio-economic developments (e.g. agricultural intensification and on-going urbanisation) and an increase in climate variability, the pressure on these water bodies is growing. Optimization of water availability by taking into account the needs of different users, both in wet and dry periods, is crucial for sustainable developments. To support timely and well-directed operational water management, accurate information on the current state of the system as well as reliable models to evaluate water management optimization measures are essential. Previous studies showed that the use of remote sensing data (for example soil moisture data) in water management offers many opportunities (e.g. Wanders et al. (2014)). However, these data are not yet used in operational applications at a large scale. The Sentinel-1 satellites programme offers high spatiotemporal resolution soil moisture data (1 image per 6 days with a spatial resolution of 10 by 10 m) that are freely available. In this study, these data will be used to improve the Netherlands Hydrological Instrument (NHI). The NHI consists of coupled models for the unsaturated zone (MetaSWAP), groundwater (iMODFLOW) and surface water (Mozart and DM). The NHI is used for scenario analyses and operational water management in the Netherlands (De Lange et al., 2014). Due to the lack of soil moisture data, the unsaturated zone model is not yet thoroughly validated and its output is not used by regional water authorities for decision-making. Therefore, the newly acquired remotely sensed soil moisture data will be used to improve the skill of the MetaSWAP-model and the NHI as whole. The research will focus among other things on the calibration of soil parameters by comparing model output (MetaSWAP) with the remotely sensed soil moisture data. Eventually, we want to apply data-assimilation to improve

  2. CARMENES instrument control system and operational scheduler

    Science.gov (United States)

    Garcia-Piquer, Alvaro; Guàrdia, Josep; Colomé, Josep; Ribas, Ignasi; Gesa, Lluis; Morales, Juan Carlos; Pérez-Calpena, Ana; Seifert, Walter; Quirrenbach, Andreas; Amado, Pedro J.; Caballero, José A.; Reiners, Ansgar

    2014-07-01

    The main goal of the CARMENES instrument is to perform high-accuracy measurements of stellar radial velocities (1m/s) with long-term stability. CARMENES will be installed in 2015 at the 3.5 m telescope in the Calar Alto Observatory (Spain) and it will be equipped with two spectrographs covering from the visible to the near-infrared. It will make use of its near-IR capabilities to observe late-type stars, whose peak of the spectral energy distribution falls in the relevant wavelength interval. The technology needed to develop this instrument represents a challenge at all levels. We present two software packages that play a key role in the control layer for an efficient operation of the instrument: the Instrument Control System (ICS) and the Operational Scheduler. The coordination and management of CARMENES is handled by the ICS, which is responsible for carrying out the operations of the different subsystems providing a tool to operate the instrument in an integrated manner from low to high user interaction level. The ICS interacts with the following subsystems: the near-IR and visible channels, composed by the detectors and exposure meters; the calibration units; the environment sensors; the front-end electronics; the acquisition and guiding module; the interfaces with telescope and dome; and, finally, the software subsystems for operational scheduling of tasks, data processing, and data archiving. We describe the ICS software design, which implements the CARMENES operational design and is planned to be integrated in the instrument by the end of 2014. The CARMENES operational scheduler is the second key element in the control layer described in this contribution. It is the main actor in the translation of the survey strategy into a detailed schedule for the achievement of the optimization goals. The scheduler is based on Artificial Intelligence techniques and computes the survey planning by combining the static constraints that are known a priori (i.e., target

  3. Robot force control for hazardous drilling operations

    Science.gov (United States)

    Alici, Gursel; Daniel, R. W.

    The use of robot manipulators for tasks which are inherently risky for human beings, specifically hazardous drilling operations, is investigated. Although drilling is one of the simplest and most basic metal cutting processes, robot drilling is problematic and has resulted in extreme operator fatigue and shorter drill life under telemanipulator control due to a number of possible causes such as dynamic and static effects. Both originate from differences between a robot and a drilling machine. A detailed study of the task highlighted the fact that it is necessary to regulate the distance dependent force by closed loop force control. How the robot type force could be controlled together with the robot position to allow fast drilling but without too much drill wear was considered. The answer was found in further exploration of the tasks which generated a set of specifications and problems that were addressed using novel strategies rather than those usually adopted for robots. The possible solutions are given in terms of a new control strategy and the correct choice of coordinate system to be used within that strategy.

  4. 47 CFR 78.51 - Remote control operation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Remote control operation. 78.51 Section 78.51... SERVICE General Operating Requirements § 78.51 Remote control operation. (a) A CARS station may be operated by remote control: Provided, That such operation is conducted in accordance with the conditions...

  5. Operational control of radiation conditions in Space Monitoring Data Center of Moscow State University

    Science.gov (United States)

    Kalegaev, Vladimir; Shugay, Yulia; Bobrovnikov, Sergey; Kuznetsov, Nikolay; Barinova, Vera; Myagkova, Irina; Panasyuk, Mikhail

    2016-07-01

    Space Monitoring Data Center (SMDC) of Moscow State University provides mission support for Russian satellites and give operational analysis of radiation conditions in space. SMDC Web-sites (http://smdc.sinp.msu.ru/ and http://swx.sinp.msu.ru/) give access to current data on the level of solar activity, geomagnetic and radiation state of Earth's magnetosphere and heliosphere in near-real time. For data analysis the models of space environment factors working online have been implemented. Interactive services allow one to retrieve and analyze data at a given time moment. Forecasting applications including solar wind parameters, geomagnetic and radiation condition forecasts have been developed. Radiation dose and SEE rate control are of particular importance in practical satellite operation. Satellites are always under the influence of high-energy particle fluxes during their orbital flight. The three main sources of particle fluxes: the Earth's radiation belts, the galactic cosmic rays, and the solar energetic particles (SEP), are taken into account by SMDC operational services to estimate the radiation dose caused by high-energy particles to a satellite at LEO orbits. ISO 15039 and AP8/AE8 physical models are used to estimate effects of galactic cosmic rays and radiation belt particle fluxes. Data of geosynchronous satellites (GOES or Electro-L1) allow to reconstruct the SEP fluxes spectra at a given low Earth orbit taking into account the geomagnetic cut-off depending on geomagnetic activity level.

  6. Human reliability analysis of control room operators

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Isaac J.A.L.; Carvalho, Paulo Victor R.; Grecco, Claudio H.S. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)

    2005-07-01

    Human reliability is the probability that a person correctly performs some system required action in a required time period and performs no extraneous action that can degrade the system Human reliability analysis (HRA) is the analysis, prediction and evaluation of work-oriented human performance using some indices as human error likelihood and probability of task accomplishment. Significant progress has been made in the HRA field during the last years, mainly in nuclear area. Some first-generation HRA methods were developed, as THERP (Technique for human error rate prediction). Now, an array of called second-generation methods are emerging as alternatives, for instance ATHEANA (A Technique for human event analysis). The ergonomics approach has as tool the ergonomic work analysis. It focus on the study of operator's activities in physical and mental form, considering at the same time the observed characteristics of operator and the elements of the work environment as they are presented to and perceived by the operators. The aim of this paper is to propose a methodology to analyze the human reliability of the operators of industrial plant control room, using a framework that includes the approach used by ATHEANA, THERP and the work ergonomics analysis. (author)

  7. Adaptive sliding mode control of tethered satellite deployment with input limitation

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2016-10-01

    This paper proposes a novel adaptive sliding mode tension control method for the deployment of tethered satellite, where the input tension limitation is taken into account. The underactuated governing equations of the tethered satellites system are firstly derived based on Lagrangian mechanics theory. Considering the fact that the tether can only resist axial stretching, the tension input is modelled as input limitation. New adaptive sliding mode laws are addressed to guarantee the stability of the tethered satellite deployment with input disturbance, meanwhile to eliminate the effect of the limitation features of the tension input. Compared with the classic control strategy, the newly proposed adaptive sliding mode control law can deploy the satellite with smaller overshoot of the in-plane angle and implement the tension control reasonably and effectively in engineering practice. The numerical results validate the effectiveness of the proposed methods.

  8. Design and simulation of satellite attitude control system based on Simulink and VR

    Science.gov (United States)

    Zhang, Yang; Gan, Qingbo; Kang, Jingshu

    2016-01-01

    In order to research satellite attitude control system design and visual simulation, the simulation framework of satellite dynamics and attitude control using Simulink were established. The design of satellite earth-oriented control system based on quaternion feedback was completed. The 3D scene based on VR was created and models in the scene were driven by simulation data of Simulink. By coordinate transformation. successful observing the scene in inertial coordinate system, orbit coordinate system and body coordinate system. The result shows that application of simulation method of Simulink combined with VR in the design of satellite attitude control system field, has the advantages of high confidence level, hard real-time property, multi-perspective and multi-coordinate system observing the scene, and improves the comprehensibility and accuracy of the design.

  9. 47 CFR 80.969 - Illumination of operating controls.

    Science.gov (United States)

    2010-10-01

    ... illuminate the operating controls at the principal operating position. (b) Instead of dial lights, a light from an electric lamp may be provided to illuminate the operating controls of the radiotelephone at...

  10. Operation and Control of Enzymatic Biodiesel Production

    DEFF Research Database (Denmark)

    Price, Jason Anthony; Huusom, Jakob Kjøbsted; Nordblad, Mathias

    -product. Current literature indicates that enzymatic processing of oils and fats to produce biodiesel is technically feasible and developments in immobilization technology indicate that enzyme catalysts can become cost effective compared to chemical processing. However, with very few exceptions, enzyme technology...... is not currently used in commercial-scale biodiesel production. This is mainly due to non-optimized process designs, which do not use the full potential of the catalysts in a cost-efficient way. Furthermore is it unclear what process variables need to be monitored and controlled to ensure optimal economics...... an enzymatic route, batch operation is a straightforward and efficient means for producing BD with its main disadvantage being the downtime between batches. For large-scale production of biodiesel, continuous operation is an attractive alternative as it enables efficient use of manpower and capital assets...

  11. From satellite altimetry to Argo and operational oceanography: three revolutions in oceanography

    Science.gov (United States)

    Le Traon, P. Y.

    2013-10-01

    The launch of the French/US mission Topex/Poseidon (T/P) (CNES/NASA) in August 1992 was the start of a revolution in oceanography. For the first time, a very precise altimeter system optimized for large-scale sea level and ocean circulation observations was flying. T/P alone could not observe the mesoscale circulation. In the 1990s, the ESA satellites ERS-1/2 were flying simultaneously with T/P. Together with my CLS colleagues, we demonstrated that we could use T/P as a reference mission for ERS-1/2 and bring the ERS-1/2 data to an accuracy level comparable to T/P. Near-real-time high-resolution global sea level anomaly maps were then derived. These maps have been operationally produced as part of the SSALTO/DUACS system for the last 15 yr. They are now widely used by the oceanographic community and have contributed to a much better understanding and recognition of the role and importance of mesoscale dynamics. Altimetry needs to be complemented with global in situ observations. At the end of the 90s, a major international initiative was launched to develop Argo, the global array of profiling floats. This has been an outstanding success. Argo floats now provide the most important in situ observations to monitor and understand the role of the ocean on the earth climate and for operational oceanography. This is a second revolution in oceanography. The unique capability of satellite altimetry to observe the global ocean in near-real-time at high resolution and the development of Argo were essential for the development of global operational oceanography, the third revolution in oceanography. The Global Ocean Data Assimilation Experiment (GODAE) was instrumental in the development of the required capabilities. This paper provides an historical perspective on the development of these three revolutions in oceanography which are very much interlinked. This is not an exhaustive review and I will mainly focus on the contributions we made together with many colleagues and

  12. From satellite altimetry to Argo and operational oceanography: three revolutions in oceanography

    Directory of Open Access Journals (Sweden)

    P. Y. Le Traon

    2013-10-01

    Full Text Available The launch of the French/US mission Topex/Poseidon (T/P (CNES/NASA in August 1992 was the start of a revolution in oceanography. For the first time, a very precise altimeter system optimized for large-scale sea level and ocean circulation observations was flying. T/P alone could not observe the mesoscale circulation. In the 1990s, the ESA satellites ERS-1/2 were flying simultaneously with T/P. Together with my CLS colleagues, we demonstrated that we could use T/P as a reference mission for ERS-1/2 and bring the ERS-1/2 data to an accuracy level comparable to T/P. Near-real-time high-resolution global sea level anomaly maps were then derived. These maps have been operationally produced as part of the SSALTO/DUACS system for the last 15 yr. They are now widely used by the oceanographic community and have contributed to a much better understanding and recognition of the role and importance of mesoscale dynamics. Altimetry needs to be complemented with global in situ observations. At the end of the 90s, a major international initiative was launched to develop Argo, the global array of profiling floats. This has been an outstanding success. Argo floats now provide the most important in situ observations to monitor and understand the role of the ocean on the earth climate and for operational oceanography. This is a second revolution in oceanography. The unique capability of satellite altimetry to observe the global ocean in near-real-time at high resolution and the development of Argo were essential for the development of global operational oceanography, the third revolution in oceanography. The Global Ocean Data Assimilation Experiment (GODAE was instrumental in the development of the required capabilities. This paper provides an historical perspective on the development of these three revolutions in oceanography which are very much interlinked. This is not an exhaustive review and I will mainly focus on the contributions we made together with many

  13. [Testing results of telemechanic system controlling train operators wakefulness].

    Science.gov (United States)

    Serikov, V V; Zakrevskaia, A A; Zakharchenko, D V; Alpaev, D V; At'kova, E O

    2015-01-01

    Expert and instrumental assessment covered efficiency of telemechanic system controlling train operators wakefulness in simulation of real night travel, through special simulator complex "Locomotive operator cabin". The telemechanic system controlling train operators wakefulness, if exploited correctly, provides wakefulness of the train operators at the level sufficient for the effective work. That is supported by distribution of falling asleep cases in experiments with activated or deactivated telemechanic system controlling train operators wakefulness. The study proved efficiency of telemechanic system controlling train operators wakefulness.

  14. The COASTALT Project: Towards an Operational Use of Satellite Altimetry in the Coastal Zone

    Science.gov (United States)

    Vignudelli, S.; Cipollini, P.; Gommenginger, C.; Snaith, H. M.; Coelho, E.; Fernandes, J.; Gomez-Henri, J.; Martin-Puig, C.; Woodworth, P. L.; Dinardo, S.; Benveniste, J. J.

    2009-12-01

    The coastal zone is the unique part of the Earth where land, sea, air and people meet. By its nature it is a complex system where all the processes that influence its functioning, whether physical, biological, chemical, social, climatological or geological, are interconnected. It requires an integrated approach benefiting from a synergy of modeling tools and multiple datasets created from space, air, land and ocean-based earth observing systems. An important property monitored from space using radar altimetry is the sea level, an index of variability of the ocean circulation. Since 1991, satellite altimetry has had exceptional success over the open ocean. However, the processing strategy used in the open ocean has not been of much success in getting sea level in the coastal zone. The advantage of current radar altimetry for coastal studies is that it can fill gaps in the vast areas around tide gauges which are running continu¬ously, but in only a few places. The coastal domain represents a challenging target for processing of satellite data in general; for satellite altimetry, the data retrieval is required to address some problems including: (1) re-tracking (important for the last 10 km next to the coast), (2) a more accurate wet troposphere path delay correction, (3) better modeling of tidal and atmospheric effects. A global record of length 17 years of raw data from a series of altimetry missions is presently available and represents a unique resource for retrospective analysis in the coastal zone. A great impetus has been given to the field by the recent launch of two major projects devoted to the development of coastal altimetry products for specific missions: PISTACH, by CNES focused on Jason-2 and COASTALT, by ESA for Envisat. In parallel, NASA is sustaining coastal altimetry research through specific R&D projects in response to the last OSTST call. This new “coastal altimetry” community, inherently interdisciplinary, has already had two well

  15. Observation operator for the assimilation of aerosol type resolving satellite measurements into a chemical transport model

    Directory of Open Access Journals (Sweden)

    M. Schroedter-Homscheidt

    2010-11-01

    Full Text Available Modelling of aerosol particles with chemical transport models is still based mainly on static emission databases while episodic emissions cannot be treated sufficiently. To overcome this situation, a coupling of chemical mass concentration modelling with satellite-based measurements relying on physical and optical principles has been developed. This study deals with the observation operator for a component-wise assimilation of satellite measurements. It treats aerosol particles classified into water soluble, water insoluble, soot, sea salt and mineral dust containing aerosol particles in the atmospheric boundary layer as separately assimilated aerosol components. It builds on a mapping of aerosol classes used both in observation and model space taking their optical and chemical properties into account. Refractive indices for primary organic carbon particles, anthropogenic particles, and secondary organic species have been defined based on a literature review. Together with a treatment of different size distributions in observations and model state, this allows transforming the background from mass concentrations into aerosol optical depths. A two-dimensional, variational assimilation is applied for component-wise aerosol optical depths. Error covariance matrices are defined based on a validation against AERONET sun photometer measurements. Analysis fields are assessed threefold: (1 through validation against AERONET especially in Saharan dust outbreak situations, (2 through comparison with the British Black Smoke and Sulphur Dioxide Network for soot-containing particles, and (3 through comparison with measurements of the water soluble components SO4, NH4, and NO3 conducted by the EMEP (European Monitoring and Evaluation Programme network. Separately, for the water soluble, the soot and the mineral dust aerosol components a bias reduction and subsequent a root mean square error reduction is observed in the

  16. Operating System For Numerically Controlled Milling Machine

    Science.gov (United States)

    Ray, R. B.

    1992-01-01

    OPMILL program is operating system for Kearney and Trecker milling machine providing fast easy way to program manufacture of machine parts with IBM-compatible personal computer. Gives machinist "equation plotter" feature, which plots equations that define movements and converts equations to milling-machine-controlling program moving cutter along defined path. System includes tool-manager software handling up to 25 tools and automatically adjusts to account for each tool. Developed on IBM PS/2 computer running DOS 3.3 with 1 MB of random-access memory.

  17. Operating System For Numerically Controlled Milling Machine

    Science.gov (United States)

    Ray, R. B.

    1992-01-01

    OPMILL program is operating system for Kearney and Trecker milling machine providing fast easy way to program manufacture of machine parts with IBM-compatible personal computer. Gives machinist "equation plotter" feature, which plots equations that define movements and converts equations to milling-machine-controlling program moving cutter along defined path. System includes tool-manager software handling up to 25 tools and automatically adjusts to account for each tool. Developed on IBM PS/2 computer running DOS 3.3 with 1 MB of random-access memory.

  18. Two way satellite communication for telemetrology and remote control

    Science.gov (United States)

    Hanebrekke, H.

    Low-data-rate satellite communication to fixed and floating buoys at sea, remote observation stations, and fishing vessels is studied. Particular attention is paid to Norwegian conditions, that is, high latitude and high mountains. Coverage and reliability measurements utilizing Inmarsat C and Prodat stations have been done along the coast of western and northern Norway, and on major roads in southern Norway. Good coverage is found in the coastal areas, with only 5 percent loss of messages when both the AOR and IOR satellites are used from the same location, whereas the land mobile experiments gave 40 percent to 70 percent loss, depending on the elevation angle. The possibility of using Inmarsat C or Prodat stations in the major fishing areas between Norway, Greenland, and Svalbard and in the Barents Sea are also being investigated. A method of data collection from ocean areas based on the fishing fleet is proposed.

  19. Design of Satellite Attitude Control Algorithm Based on the SDRE Method Using Gas Jets and Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Luiz C. G. de Souza

    2013-01-01

    Full Text Available An experimental attitude control algorithm design using prototypes can minimize space mission costs by reducing the number of errors transmitted to the next phase of the project. The Space Mechanics and Control Division (DMC of INPE is constructing a 3D simulator to supply the conditions for implementing and testing satellite control hardware and software. Satellite large angle maneuver makes the plant highly nonlinear and if the parameters of the system are not well determined, the plant can also present some level of uncertainty. As a result, controller designed by a linear control technique can have its performance and robustness degraded. In this paper the standard LQR linear controller and the SDRE controller associated with an SDRE filter are applied to design a controller for a nonlinear plant. The plant is similar to the DMC 3D satellite simulator where the unstructured uncertainties of the system are represented by process and measurements noise. In the sequel the State-Dependent Riccati Equation (SDRE method is used to design and test an attitude control algorithm based on gas jets and reaction wheel torques to perform large angle maneuver in three axes. The SDRE controller design takes into account the effects of the plant nonlinearities and system noise which represents uncertainty. The SDRE controller performance and robustness are tested during the transition phase from angular velocity reductions to normal mode of operation with stringent pointing accuracy using a switching control algorithm based on minimum system energy. This work serves to validate the numerical simulator model and to verify the functionality of the control algorithm designed by the SDRE method.

  20. Operational Estimation of Accumulated Precipitation using Satellite Observation, by Eumetsat Satellite Application facility in Support to Hydrology (H-SAF Consortium).

    Science.gov (United States)

    di Diodato, A.; de Leonibus, L.; Zauli, F.; Biron, D.; Melfi, D.

    2009-04-01

    Operational Estimation of Accumulated Precipitation using Satellite Observation, by Eumetsat Satellite Application facility in Support to Hydrology (H-SAF Consortium). Cap. Attilio DI DIODATO(*), T.Col. Luigi DE LEONIBUS(*), T.Col Francesco ZAULI(*), Cap. Daniele BIRON(*), Ten. Davide Melfi(*) Satellite Application Facilities (SAFs) are specialised development and processing centres of the EUMETSAT Distributed Ground Segment. SAFs process level 1b data from meteorological satellites (geostationary and polar ones) in conjunction with all other relevant sources of data and appropriate models to generate services and level 2 products. Each SAF is a consortium of EUMETSAT European partners lead by a host institute responsible for the management of the complete SAF project. The Meteorological Service of Italian Air Force is the host Institute for the Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF). HSAF has the commitment to develop and to provide, operationally after 2010, products regarding precipitation, soil moisture and snow. HSAF is going to provide information on error structure of its products and validation of the products via their impacts into Hydrological models. To that purpose it has been structured a specific subgroups. Accumulated precipitation is computed by temporal integration of the instantaneous rain rate achieved by the blended LEO/MW and GEO/IR precipitation rate products generated by Rapid Update method available every 15 minutes. The algorithm provides four outputs, consisting in accumulated precipitation in 3, 6, 12 and 24 hours, delivered every 3 hours at the synoptic hours. These outputs are our precipitation background fields. Satellite estimates can cover most of the globe, however, they suffer from errors due to lack of a direct relationship between observation parameters and precipitation, the poor sampling and algorithm imperfections. For this reason the 3 hours accumulated precipitation is

  1. Orbit Control of Fly-around Satellite with Highly Eccentric Orbit Using Solar Radiation Pressure

    Science.gov (United States)

    Yong-gang, Hou; Chang-yin, Zhao; Ming-jiang, Zhang; Rong-yu, Sun

    2017-01-01

    The method of controlling highly eccentric accompanying flight orbit using the solar wing is proposed in this paper. The formation is maintained by controlling the orbit of the accompanying satellite (follower). The accompanying satellite rotates around its inertial principal axis with a constant angular velocity. The control on the accompanying satellite is divided into the in-plane control and out-of-plane control. The in-plane control is superior to the out-of-plane control. The out-of-plane control force is applied when the in-plane error is eliminated or the in-plane control force can not be supplied due to some geometrical factors. By the sliding mode control method, the magnitude and direction of the control force required by the in-plane orbit control are calculated. Then accordingly, the expression of the solar wing orientation with respect to the satellite body in the control process is derived, so that by adjusting the orientation of the solar wing, the required control force can be obtained. Finally, the verification on this method is performed by numerical simulations, including the orbit adjustment, error elimination, and the orbit maintenance. It is shown that this method can keep the error less than 5 m, and it is feasible for the space formation flight.

  2. 47 CFR 74.634 - Remote control operation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Remote control operation. 74.634 Section 74.634... Stations § 74.634 Remote control operation. (a) A TV auxiliary station may be operated by remote control... controlled by persons authorized by the licensee. (2) The remote control equipment must be maintained to...

  3. 47 CFR 74.434 - Remote control operation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Remote control operation. 74.434 Section 74.434....434 Remote control operation. (a) A remote control system must provide adequate monitoring and control functions to permit proper operation of the station. (b) A remote control system must be designed, installed...

  4. 47 CFR 74.533 - Remote control and unattended operation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Remote control and unattended operation. 74.533... Auxiliary Stations § 74.533 Remote control and unattended operation. (a) Aural broadcast STL and intercity relay stations may be operated by remote control provided that such operation is conducted in accordance...

  5. Attitude dynamics of gyrostat-satellites under control by magnetic actuators at small perturbations

    Science.gov (United States)

    Doroshin, Anton V.

    2017-08-01

    The angular motion of gyrostat-satellites with one axial rotor is considered under control by magnetic actuators and at the action of small polyharmonic perturbations of the own dipole magnetic moment's components which are created proportionally to components of the angular velocity of the satellite. The attitude dynamics is investigated in conditions of the coincidence of the vector of magnetic induction of the external magnetic field and the initial angular momentum vector of the satellite. General and heteroclinic analytical solutions are obtained for dynamical parameters at the relative smallness of the magnetic torques. The chaotic regimes are examined on the base of the Melnikov method and Poincaré sections.

  6. Linear Time Varying Approach to Satellite Attitude Control Using only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    1997-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technological improvement of micro-electronics. Required pointing accuracy of small, inexpensive satellites is often relatively loose, within a couple of degrees. Application of cheap......, lightweight, and power efficient actuators is therefore crucial and viable. This paper discusses linear attitude control strategies for a low earth orbit satellite actuated by a set of mutually perpendicular electromagnetic coils. The principle is to use the interaction between the Earth's magnetic field...... and the magnetic field generated by the coils. A key challenge is the fact that the mechanical torque can only be produced in a plane perpendicular to the local geomagnetic field vector, therefore the satellite is not controllable when considered at fixed time. Availability of design methods for time varying...

  7. Linear Time Varying Approach to Satellite Attitude Control Using only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    Recently small satellite missions have gained considerable interest due to low-cost launch opportunities and technological improvemant of micro-electronics. Required pointing accuracy of small, inexpensive satellites is often relatively loose, within a couple of degrees. Application of cheap......, lightweight, and power efficient actuators is therefore crucial and viable. This paper discusser linear attitude control strategies for a low earth orbit satellite actuated by a set of mutually perpendicular electromagnetic coils. The principle is to use the interaction between the Earth's magnetic field...... and the magnetic field generated by the coils. A key challenge is the fact that the mechanical torque can only be produced in a plane perpendicular to the local geomagnetic field vector, therefore the satellite is not controllable at fixed time. Avaliability of design methods for time varying systems is limited...

  8. A Weekly Indicator of Surface Moisture Status from Satellite Data for Operational Monitoring of Crop Conditions

    Directory of Open Access Journals (Sweden)

    Francesco Nutini

    2017-06-01

    Full Text Available The triangle method has been applied to derive a weekly indicator of evaporative fraction on vegetated areas in a temperate region in Northern Italy. Daily MODIS Aqua Land Surface Temperature (MYD11A1 data has been combined with air temperature maps and 8-day composite MODIS NDVI (MOD13Q1/MYD13Q1 data to estimate the Evaporative Fraction (EF at 1 km resolution, on a daily basis. Measurements at two eddy covariance towers located within the study area have been exploited to assess the reliability of satellite based EF estimations as well as the robustness of input data. Weekly syntheses of the daily EF indicator (EFw were then derived at regional scale for the years 2010, 2011 and 2012 as a proxy of overall surface moisture condition. EFw showed a temporal behavior consistent with growing cycles and agro-practices of the main crops cultivated in the study area (rice, forages and corn. Comparison with official regional corn yield data showed that variations in EFw cumulated over summer are related with crop production shortages induced by water scarcity. These results suggest that weekly-averaged EF estimated from MODIS data is sensible to water stress conditions and can be used as an indicator of crops’ moisture conditions at agronomical district level. Advantages and disadvantages of the proposed approach to provide information useful to issue operational near real time bulletins on crop conditions at regional scale are discussed.

  9. Modelling and prediction of crop losses from NOAA polar-orbiting operational satellites

    Directory of Open Access Journals (Sweden)

    Felix Kogan

    2016-05-01

    Full Text Available Weather-related crop losses have always been a concern for farmers, governments, traders, and policy-makers for the purpose of balanced food supply/demands, trade, and distribution of aid to the nations in need. Among weather disasters, drought plays a major role in large-scale crop losses. This paper discusses utility of operational satellite-based vegetation health (VH indices for modelling cereal yield and for early warning of drought-related crop losses. The indices were tested in Saratov oblast (SO, one of the principal grain growing regions of Russia. Correlation and regression analysis were applied to model cereal yield from VH indices during 1982–2001. A strong correlation between mean SO's cereal yield and VH indices were found during the critical period of cereals, which starts two–three weeks before and ends two–three weeks after the heading stage. Several models were constructed where VH indices served as independent variables (predictors. The models were validated independently based on SO cereal yield during 1982–2012. Drought-related cereal yield losses can be predicted three months in advance of harvest and six–eight months in advance of official grain production statistic is released. The error of production losses prediction is 7%–10%. The error of prediction drops to 3%–5% in the years of intensive droughts.

  10. Program on stimulating operational private sector use of Earth observation satellite information

    Science.gov (United States)

    Eastwood, L. F., Jr.; Foshage, J.; Gomez, G.; Kirkpatrick, B.; Konig, B.; Stein, R. (Principal Investigator)

    1981-01-01

    Ideas for new businesses specializing in using remote sensing and computerized spatial data systems were developd. Each such business serves as an 'information middleman', buying raw satellite or aircraft imagery, processing these data, combining them in a computer system with customer-specific information, and marketing the resulting information products. Examples of the businesses the project designed are: (1) an agricultural facility site evaluation firm; (2) a mass media grocery price and supply analyst and forecaster; (3) a management service for privately held woodlots; (4) a brokerage for insulation and roofing contractors, based on infrared imagery; (5) an expanded real estate information service. In addition, more than twenty-five other commercially attractive ideas in agribusiness, forestry, mining, real estate, urban planning and redevelopment, and consumer information were created. The commercial feasibility of the five business was assessed. This assessment included market surveys, revenue projections, cost analyses, and profitability studies. The results show that there are large and enthusiastic markets willing to pay for the services these businesses offer, and that the businesses could operate profitably.

  11. From satellite altimetry to operational oceanography and Argo: three revolutions in oceanography (Fridtjof Nansen Medal Lecture)

    Science.gov (United States)

    Le Traon, P. Y.

    2012-04-01

    The launch of the US/French mission Topex/Poseidon (T/P) (CNES/NASA) in August 1992 was the start of a revolution in oceanography. For the first time, a very precise altimeter system optimized for large scale sea level and ocean circulation observations was flying. Topex/Poseidon revolutionized our vision and understanding of the ocean. It provided new views of the large scale seasonal and interannual sea level and ocean circulation variations. T/P alone could not observe the mesoscale circulation. In the 1990s, the ESA satellites ERS-1/2 were flying simultaneously with T/P. The ERS-1/2 orbit was well adapted for mesoscale circulation sampling but the orbit determination and altimeter performance were much less precise than for T/P. We demonstrated that we could use T/P as a reference mission for ERS-1/2 and bring the ERS-1/2 data to an accuracy level comparable to T/P. This was an essential first step for the merging of T/P and ERS-1/2. The second step required the development of a global optimal interpolation method. Near real time high resolution global sea level anomaly maps were then derived. These maps have been operationally produced as part of the SSALTO/DUACS system for the last 15 years. They are now widely used by the oceanographic community and have contributed to a much better understanding and recognition of the role and importance of mesoscale dynamics. The unique capability of satellite altimetry to observe the global ocean in near real time at high resolution was essential to the development of global ocean forecasting, a second revolution in oceanography. The Global Ocean Data Assimilation Experiment (GODAE) (1998-2008) was phased with the T/P and ERS-1/2 successors (Jason-1 and ENVISAT) and was instrumental in the development of global operational oceanography capabilities. Europe played a leading role in GODAE. In 1998, the global in-situ observing system was inadequate for the global scope of GODAE. This led to the development of Argo, an

  12. Upper atomosphere and Thermal control of the Super Low Altitude Test Satellite

    OpenAIRE

    2013-01-01

    The Super Low Altitude Test Satellite (SLATS) is an engineering test satellite currently under development in JAXA in an attempt to open a new frontier of space utilization on extremely low earth orbits. The altitude of SLATS orbit is around200km altitude. In this altitude, rarefied aerodynamics and high-density atomic oxygen effect on the thermal design of SLATS. The thermal control of SLATS was introduced in this paper. And, the equilibrium temperature on the bumper of SLATS was estimated w...

  13. Mastering operational limitations of LEO satellites - the GomX-3 approach

    NARCIS (Netherlands)

    Nies, Gilles; Stenger, Marvin; Krčál, Jan; Hermanns, Holger; Bisgaard, Morten; Gerhardt, David; Haverkort, Boudewijn; Jongerden, Marijn; Larsen, Kim G.; Wognsen, Erik R.

    2016-01-01

    When working with space systems the keyword is resources. For a satellite in orbit all resources are sparse and the most critical resource of all is power. It is therefore crucial to have detailed knowledge on how much power is available for an energy harvesting satellite in orbit at every time – es

  14. Lightning climatology over Jakarta, Indonesia, based on long-term surface operational, satellite, and campaign observations

    Science.gov (United States)

    Mori, Shuichi; Wu, Peiming; Yamanaka, Manabu D.; Hattori, Miki; Hamada, Jun-Ichi; Arbain, Ardhi A.; Lestari, Sopia; Sulistyowati, Reni; Syamsudin, Fadli

    2016-04-01

    Lightning frequency over Indonesian Maritime Continent (MC) is quite high (Petersen and Rutledge 2001, Christian et al. 2003, Takayabu 2006, etc). In particular, Bogor (south of Jakarta, west Jawa) had 322 days of lightning in one year (Guinness Book in 1988). Lightning causes serious damage on nature and society over the MC; forest fore, power outage, inrush/surge currents on many kinds of electronics. Lightning climatology and meso-scale characteristics of thunderstorm over the MC, in particular over Jakarta, where social damage is quite serious, were examined. We made Statistical analysis of lightning and thunderstorm based on TRMM Lightning Image Sensor (LIS) and Global Satellite Mapping of Precipitation (GSMaP) together with long-term operational surface observation data (SYNOP) in terms of diurnal, intraseasonal, monsoonal, and interannual variations. In addition, we carried out a campaign observation in February 2015 in Bogor to obtain meso-scale structure and dynamics of thunderstorm over Jakarta to focus on graupel and other ice phase particles inside by using an X-band dual-polarimetric (DP) radar. Recently, Virts et al. (2013a, b) showed comprehensive lightning climatology based on the World Wide Lightning Location Network (WWLLN). However, they also reported problems with its detection efficiency (< 10%) and small sampling frequency (< 0.1% of the time fly over tropics) by satellites. Therefore, we firstly examine in situ lightning data based on SYNOP observed by the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) because lightning is quite local and sporadic phenomena. We've started to analyze lightning characteristics over Jakarta region based on SYNOP as the ground truth data and GSMaP. Variability of lightning frequency around Jakarta was affected much by local conditions, e.g., topography (elevation) and proximity to the coastline. We confirmed the lightning frequency and its diurnal variation around Jakarta were much

  15. A Proposed Student Built and Operated Satellite: The Gamma Ray Burst Polarization Observer (PolOSat)

    Science.gov (United States)

    Malphrus, Benjamin K.; Jernigan, J. G.; Bloom, J. S.; Boggs, S.; Butler, N. R.; Cominsky, L. R.; Doering, T. J.; Doty, J. P.; Erb, D. M.; Figer, D. F.; Hurley, K. C.; Kimel, K. W.; Lumpp, J. E.; Labov, S.

    2009-01-01

    The Polarization Observer (PolOSat) is small satellite mission whose goal is to measure the polarization of bright gamma-ray bursts (GRBs). A precise measurement of the polarization of GRBs will constrain the models of radiative mechanisms associated with GRBs as supermassive stars undergo collapse into black holes. The primary goal of PolOSat is the detection of strongly linearly polarized GRBs (≥20; %) and/or to set upper limits on polarization for a few GRBs (≤30; %). PolOSat is designed to have a sensitivity to polarization that exceeds all prior experiments. The primary scientific instrument, the Gamma-ray Polarization Monitor (GPM) is based on a CMOS hybrid array that is optimized for performance in the low energy gamma-ray band (20-200 keV). The GPM has two passive Beryllium (Be) scattering elements which provide signal gamma-rays within a large field of view (two 45 degree radius cones). Gamma-rays impinge on the Be scatterers and are then Compton scattered into the CZT arrays and detected. A bright GRB (occurring 5 times a year) will produce 100,000s of direct gamma-rays and 1000s of Compton scattered gamma-rays detected by the CZT array. The PolOSat satellite with the GPM is rotated ( 1 Hz) inducing a strong temporal component at twice the spin frequency that is proportional to the linear polarization in the GRB signal. The team includes the University of California, Berkeley, the Kentucky Space Program including the Kentucky Science and Technology Corporation, the University of Kentucky, Morehead State University, Sonoma State University, the Rochester Institute of Technology, the University of Rochester and the Lawrence Livermore National Laboratory. PolOSat features significant participation by undergraduate and graduate students in all phases of development and operation of the spacecraft and instruments and in data analysis. PolOSat was initially proposed as a small complete NASA Mission of Opportunity and is currently seeking funding.

  16. Mechatronic Design, Dynamic Modeling and Results of a Satellite Flight Simulator for Experimental Validation of Satellite Attitude Determination and Control Schemes in 3-Axis

    Directory of Open Access Journals (Sweden)

    M.A. Mendoza-Bárcenas

    2014-06-01

    Full Text Available This paper describes the integration and implementation of a satellite flight simulator based on an air bearing system, which was designed and instrumented in our laboratory to evaluate and to perform research in the field of Attitude Determination and Control Systems for satellites, using the hardware-in-the-loop technique. The satellite flight simulator considers two main blocks: an instrumented mobile platform and an external computer executing costume-made Matlab® software. The first block is an air bearing system containing an FPGA based on-board computer with capabilities to integrate digital architectures for data acquisition from inertial navigation sensors, control of actuators and communications data handling. The second block is an external personal computer, which runs in parallel Matlab® based algorithms for attitude determination and control. Both blocks are linked by means of radio modems. The paper also presents the analysis of the satellite flight simulator dynamics in order to obtain its movement equation which allows a better understanding of the satellite flight simulator behavior. In addition, the paper shows experimental results about the automated tracking of the satellite flight simulator based a virtual reality model developed in Matlab®. It also depicts two different versions of FPGA based on-board computers developed in-house to integrate embedded and polymorphic digital architectures for spacecrafts applications. Finally, the paper shows successful experimental results for an attitude control test using the satellite flight simulator based on a linear control law.

  17. Attitude-Tracking Control with Path Planning for Agile Satellite Using Double-Gimbal Control Moment Gyros

    Directory of Open Access Journals (Sweden)

    Peiling Cui

    2012-01-01

    Full Text Available In view of the issue of rapid attitude maneuver control of agile satellite, this paper presents an attitude-tracking control algorithm with path planning based on the improved genetic algorithm, adaptive backstepping control as well as sliding mode control. The satellite applies double gimbal control moment gyro as actuator and is subjected to the external disturbance and uncertain inertia properties. Firstly, considering the comprehensive mathematical model of the agile satellite and the double gimbal control moment gyro, an improved genetic algorithm is proposed to solve the attitude path-planning problem. The goal is to find an energy optimal path which satisfies certain maneuverability under the constraints of the input saturation, actuator saturation, slew rate limit and singularity measurement limit. Then, the adaptive backstepping control and sliding mode control are adopted in the design of the attitude-tracking controller to track accurately the desired path comprised of the satellite attitude quaternion and velocity. Finally, simulation results indicate the robustness and good tracking performance of the derived controller as well as its ability to avert the singularity of double gimbal control moment gyro.

  18. Singularity Avoidance Strategies For Satellite Mounted Manipulators Using Attitude Control

    Science.gov (United States)

    1998-05-01

    assumed that 6c = 0. This allows a stabilizing control law using only a feedforward velocity term. If Hie assumption is not made, the control law...configuration, a reasonable first choice is to let Cavg = 0. The resulting control law is r = -K2e2 (200) This is also the stabilizing control law that

  19. Precise Ground-In-the-Loop Orbit Control for Low Earth Observation Satellites

    Science.gov (United States)

    Arbinger, C.; D'Amico, S.; Eineder, M.

    The growing interest in earth observation missions equipped with space-borne optical and synthetic aperture radar (SAR) sensors drives the accuracy requirements with respect to orbit determination and control. Especially SAR interferometry with its capability to resolve the velocity of on-ground objects (e.g. for traffic monitoring, ocean currents and glacier monitoring) and to determine highly precise digital elevation models is of significant interest for scientific applications. These goals may be achieved using along-track and repeat-pass interferometry with a satellite formation, based on the precise orbit control of one satellite with respect to the osculating trajectory of the second satellite. Such a control concept will be realized by the German TerraSAR-X mission, with an expected launch in 2006, using a virtual formation, where a single satellite will be controlled in a tight manner with respect to a predefined osculating reference trajectory. This is very challenging, since common orbit disturbances, like for close twin formations, do not cancel out in this scenario. The predefined trajectory in the TerraSAR-X case could also be the orbit of a second satellite. The paper describes the generation of such a virtual reference orbit, discusses the ground-in-the-loop control concept and presents results from a long-term simulation.

  20. Operational experience from the satellite fields Statfjord Nord and East; Driftserfaringer fra satellittfeltene Statfjord Nord og Oest

    Energy Technology Data Exchange (ETDEWEB)

    Retterdal, Atle; Hansen, Hans Birger [Statoil, Stavanger (Norway)

    1999-07-01

    Since production started on the satellite fields Statfjord Nord and East in 1995 and 1994, respectively, some opportunities for improvement have been discovered and realized both with respect to the subsea systems and the operational routines and philosophy. This presentation discusses the improvement projects. It is known from experience that creative ideas usually originate at the interfaces between supplier/customer, engineers with different backgrounds, or between different technologies. The interface between supplier and operator is very important for discovering creative solutions. The interface between Statoil and the suppliers of underwater equipment is not sufficiently well developed on the operational side.

  1. Drag-Free Motion Control of Satellite for High-Precision Gravity Field Mapping

    DEFF Research Database (Denmark)

    2002-01-01

    , sensors, actuators and environmental disturbances to the required micro-Newton accuracy. A control system is designed to compensate the non-gravitational disturbances on the satellite in three axes using an H∞-design. Performance is validated against mission requirements. Keywords: Spacecraft Attitude......High precision mapping of the geoid and the Earth's gravity field are of importance to a wide range of ongoing studies in areas like ocean circulation, solid Earth physics and ice sheet dynamics. Using a satellite in orbit around the Earth gives the opportunity to map the Earth's gravity field in 3...... dimensions with much better accuracy and spatial resolution than ever accomplished. To reach the desired quality of measurements, the satellite must fly in a low Earth orbit where disturbances from atmospheric drag and the Earth's magnetic field will perturb the satellite's motion. These effects...

  2. CTS /Hermes/ - United States experiments and operations summary. [Communications Technology Satellite

    Science.gov (United States)

    Donoughe, P. L.; Hunczak, H. R.

    1977-01-01

    The U.S. experiments conducted with the Communications Technology Satellite, a joint Canadian-U.S. venture launched in 1976, are discussed. The 14/12 GHz frequencies employed by the 200-W transmitter on board the satellite provide two-way television and voice communications. Applications of the satellite in the categories of health care, community services and education are considered; experiments have also made use of the special properties of the super-high frequency band (e.g. link characterization and digital communications). Time-sharing of the 14/12 GHz communication between the U.S. and Canada has functioned well.

  3. Spectrum management considerations of adaptive power control in satellite networks

    Science.gov (United States)

    Sawitz, P.; Sullivan, T.

    1983-01-01

    Adaptive power control concepts for the compensation of rain attenuation are considered for uplinks and downlinks. The performance of example power-controlled and fixed-EIRP uplinks is compared in terms of C/Ns and C/Is. Provisional conclusions are drawn with regard to the efficacy of uplink and downlink power control orbit/spectrum utilization efficiency.

  4. An operating environment for control systems on transputer networks

    NARCIS (Netherlands)

    Tillema, H.G.; Schoute, Albert L.; Wijbrans, K.C.J.; Wijbrans, K.C.J.

    1991-01-01

    The article describes an operating environment for control systems. The environment contains the basic layers of a distributed operating system. The design of this operating environment is based on the requirements demanded by controllers which can be found in complex control systems. Due to the

  5. 47 CFR 27.1210 - Remote control operation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Remote control operation. 27.1210 Section 27.1210 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES....1210 Remote control operation. Licensed BRS/EBS stations may be operated by remote control without...

  6. A COMBINED ADMISSION CONTROL ALGORITHM WITH DA PROTOCOL FOR SATELLITE ATM NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Lu Rong; Cao Zhigang

    2006-01-01

    Admission control is an important strategy for Quality of Service (QoS) provisioning in Asynchronous Transfer Mode (ATM) networks. Based on a control-theory model of resources on-Demand Allocation (DA) protocol, the paper studies the effect of the protocol on the statistical characteristics of network traffic,and proposes a combined connection admission control algorithm with the DA protocol to achieve full utilization of link resources in satellite communication systems. The proposed algorithm is based on the cross-layer-design approach. Theoretical analysis and system simulation results show that the proposed algorithm can admit more connections within certain admission thresholds than one that does not take into account the DA protocol. Thus, the proposed algorithm can increase admission ratio of traffic sources for satellite ATM networks and improve satellite link utilization.

  7. A Topology Control Strategy with Reliability Assurance for Satellite Cluster Networks in Earth Observation.

    Science.gov (United States)

    Chen, Qing; Zhang, Jinxiu; Hu, Ze

    2017-02-23

    This article investigates the dynamic topology control problemof satellite cluster networks (SCNs) in Earth observation (EO) missions by applying a novel metric of stability for inter-satellite links (ISLs). The properties of the periodicity and predictability of satellites' relative position are involved in the link cost metric which is to give a selection criterion for choosing the most reliable data routing paths. Also, a cooperative work model with reliability is proposed for the situation of emergency EO missions. Based on the link cost metric and the proposed reliability model, a reliability assurance topology control algorithm and its corresponding dynamic topology control (RAT) strategy are established to maximize the stability of data transmission in the SCNs. The SCNs scenario is tested through some numeric simulations of the topology stability of average topology lifetime and average packet loss rate. Simulation results show that the proposed reliable strategy applied in SCNs significantly improves the data transmission performance and prolongs the average topology lifetime.

  8. Operation and control software for APNEA

    Energy Technology Data Exchange (ETDEWEB)

    McClelland, J.H.; Storm, B.H. Jr.; Ahearn, J. [Lockheed-Martin Specialty Components, Largo, FL (United States)] [and others

    1997-11-01

    The human interface software for the Lockheed Martin Specialty Components (LMSC) Active/Passive Neutron Examination & Analysis System (APENA) provides a user friendly operating environment for the movement and analysis of waste drums. It is written in Microsoft Visual C++ on a Windows NT platform. Object oriented and multitasking techniques are used extensively to maximize the capability of the system. A waste drum is placed on a loading platform with a fork lift and then automatically moved into the APNEA chamber in preparation for analysis. A series of measurements is performed, controlled by menu commands to hardware components attached as peripheral devices, in order to create data files for analysis. The analysis routines use the files to identify the pertinent radioactive characteristics of the drum, including the type, location, and quantity of fissionable material. At the completion of the measurement process, the drum is automatically unloaded and the data are archived in preparation for storage as part of the drum`s data signature. 3 figs.

  9. Use and Assessment of Multi-Spectral Satellite Imagery in NWS Operational Forecasting Environments

    Science.gov (United States)

    Molthan, Andrew; Fuell, Kevin; Stano, Geoffrey; McGrath, Kevin; Schultz, Lori; LeRoy, Anita

    2015-01-01

    NOAA's Satellite Proving Grounds have established partnerships between product developers and NWS WFOs for the evaluation of new capabilities from the GOES-R and JPSS satellite systems. SPoRT has partnered with various WFOs to evaluate multispectral (RGB) products from MODIS, VIIRS and Himawari/AHI to prepare for GOES-R/ABI. Assisted through partnerships with GINA, UW/CIMSS, NOAA, and NASA Direct Broadcast capabilities.

  10. Initial Design and Concept of Operations for a Clandestine Data Relay UUV To Circumvent Jungle Canopy Effects on Satellite Communications

    Science.gov (United States)

    2011-09-01

    18 Grant Ehrlich, "Lithium-Ion Batteries ," In Handbook of Batteries (Third Edition), ed. D. Linden and T. Reddy, (New York: McGraw...Ehrlich, Grant. "Lithium-Ion Batteries ." In Handbook of Batteries (Third Edition), edited by D. Linden and T. Reddy, 35.1–35.94, New York...Concept of Operations for a Clandestine Data Relay UUV To Circumvent Jungle Canopy Effects on Satellite Communications 6. AUTHOR( S ) Michael G.Tyree

  11. Chinese Surveying and Control Network for Earth-Orbit Satellites and Deep Space Detection

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The relationship between the surveying and control network(CSN) for earth-orbit satellite and spatial geodesy, and the relationship between the CSN for deep space celestial bodies and detectors, and deep space detection are briefly summarized, and so are the basic technical needs of the deep space surveying and control network(DSN). Then, the techniques, the constituents and the distributing of Chinese satellite CSN (CSCSN) and other radio observing establishments in China are introduced. Lastly, with the primary CSCSN and other observing establishments, some projects for China to rebuild a more perfect CSCSN, and to establish a DSN are analyzed and stated.

  12. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...... tolerant controllers and analysis of   the system behaviour given possible faults.  The method is   illustrated using a simple example involving two satellites trying   to reach a specific formation despite of actuator faults occurring....

  13. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...... tolerant controllers and analysis of   the system behaviour given possible faults.  The method is   illustrated using a simple example involving two satellites trying   to reach a specific formation despite of actuator faults occurring....

  14. Design Considerations for Miniaturized Control Moment Gyroscopes for Rapid Retargeting and Precision Pointing of Small Satellites

    OpenAIRE

    Patankar, Kunal; Fitz-Coy, Norman; Roithmayr, Carlos

    2014-01-01

    This paper presents the design as well as characterization of a practical control moment gyroscope (CMG) based attitude control system (ACS) for small satellites in the 15-20 kg mass range performing rapid retargeting and precision pointing maneuvers. The paper focuses on the approach taken in the design of miniaturized CMGs while considering the constraints imposed by the use of commercial off-the-shelf (COTS) components as well as the size of the satellite. It is shown that a hybrid mode is...

  15. Controlled assembly and plasmonic properties of asymmetric core-satellite nanoassemblies.

    Science.gov (United States)

    Yoon, Jun Hee; Lim, Jonghui; Yoon, Sangwoon

    2012-08-28

    The assembly of noble metal nanoparticles offers an appealing means to control and enhance the plasmonic properties of nanostructures. However, making nanoassemblies with easily modifiable gap distances with high efficiency has been challenging. Here, we report a novel strategy to assemble gold nanoparticles (AuNPs) into Janus-type asymmetric core-satellite nanostructures. Markedly different desorption efficiency between large and small AuNPs in ethanol allows us to prepare the asymmetric core-satellite nanoassemblies in a dispersed colloidal state with near 100% purity. The resulting nanoassemblies have well-defined structures in which a core AuNP (51 nm) is covered by an average of 13 ± 3 satellite AuNPs (13 nm) with part of the core surfaces left unoccupied. Strong surface plasmon coupling is observed from these nanoassemblies as a result of the close proximity between the core and the satellites, which appears significantly red-shifted from the surface plasmon resonance frequencies of the constituting nanoparticles. The dependence of the surface plasmon coupling on a gap distance of less than 3 nm is systematically investigated by varying the length of the alkanedithiol linkers. The asymmetric core-satellite nanoassemblies also serve as an excellent surface-enhanced Raman scattering substrate with an enhancement factor of ~10(6). Finally, we demonstrate that the presented assembly method is extendible to the preparation of compositionally heterogeneous core-satellite nanoassemblies.

  16. Closed-Loop Control of Satellite Formations Using a Quasi-Rigid Body Formulation

    Science.gov (United States)

    Blake, Christopher; Misra, Arun K.

    2011-04-01

    Satellites in formation work together to fulfill the role of a larger satellite. The purpose of this article is to develop a quasi-rigid body formulation for modeling and controlling such a formation as a single entity. In this article, a definition of a quasi-rigid body coordinate frame is presented, which, when attached to a formation, conveniently describes its orientation in space. Using this formulation, the equations of motion for a satellite formation are recast, and natural circular formations are expressed more succinctly. When the J 2 perturbation is considered, a correction factor on the formation's spin rate is introduced. The control of a satellite formation can effectively be separated into (1) a control torque to maintain the attitude and (2) control forces that maintain the rigidity of the formation. With this in mind, a nonlinear Lyapunov controller is derived using the formulation, which acts on the formation as a whole. Simulations validate this controller and illustrate its utility for maintaining circular formations, in particular, in the presence of gravitational perturbations.

  17. Operator's Influence on the Safety of the Controlled Process

    Directory of Open Access Journals (Sweden)

    Peter Nagy

    2015-01-01

    Full Text Available An analysis of risks related to controlled process and related hazards identification is an important activity during the development of the safety related control system (SRCS. The mistake of the operational staff during the execution of the safety relevant operations related to controlled process can be the cause of hazard. Influence of the operator on controlled process safety depends on operation mode of the SRCS and on technical safety of the SRCS. This contribution deals with the issue of the safety assessment of the operator effect on the safety of the controlled process.

  18. A fault tolerant design for autonomous attitude control of the DSCS-III communication satellite

    Science.gov (United States)

    Matijevic, J.; Mettler, E.

    1983-01-01

    The first of a new series of satellites, which will provide the principal elements in the Defense Space Communications System (DSCS), was launched on Oct. 31, 1982. This satellite, DSCS-III, is part of a system which will consist of super-high frequency communications satellites in synchronous, equatorial orbits, continuously operating in four widely separate geographic regions. The DSCS-III is designed both to maintain critical communications in the presence of an electronic jamming threat and to survive nuclear radiation exposure. The results of the present investigation are to provide a basis for the design of a spacecraft tolerant of on-board failures, survivable against external threats, and capable of performing its mission autonomously for periods as long as six months.

  19. Nutation and precession control of the High Energy Solar Physics (HESP) satellite

    Science.gov (United States)

    Jayaraman, C. P.; Robertson, B. P.

    1993-01-01

    The High Energy Solar Physics (HESP) spacecraft is an intermediate class satellite proposed by NASA to study solar high-energy phenomena during the next cycle of high solar activity in the 1998 to 2005 time frame. The HESP spacecraft is a spinning satellite which points to the sun with stringent pointing requirements. The natural dynamics of a spinning satellite includes an undesirable effect: nutation, which is due to the presence of disturbances and offsets of the spin axis from the angular momentum vector. The proposed Attitude Control System (ACS) attenuates nutation with reaction wheels. Precessing the spacecraft to track the sun in the north-south and east-west directions is accomplished with the use of torques from magnetic torquer bars. In this paper, the basic dynamics of a spinning spacecraft are derived, control algorithms to meet HESP science requirements are discussed and simulation results to demonstrate feasibility of the ACS concept are presented.

  20. Closed-Loop Acoustic Control of Reverberant Room for Satellite Environmental Testing

    Science.gov (United States)

    Janssens, Karl; Bianciardi, Fabio; Sabbatini, Danilo; Debille, Jan; Carrella, Alex

    2012-07-01

    The full satellite acoustic test is an important milestone in a satellite launch survivability verification campaign. This test is required to verify the satellite’s mechanical design against the high-level acoustic loads induced by the launch vehicle during the atmospheric flight. During the test, the satellite is subjected to a broadband diffuse acoustic field, reproducing the pressure levels observed during launch. The excitation is in most cases provided by a combination of horns for the low frequencies and noise generators for the higher frequencies. Acoustic control tests are commonly performed in reverberant rooms, controlling the sound pressure levels in third octave bands over the specified target spectrum. This paper discusses an automatic feedback control system for acoustic control of large reverberation rooms for satellite environmental testing. The acoustic control system consists of parallel third octave PI (Proportional Integral) feedback controllers that take the reverberation characteristics of the room into consideration. The drive output of the control system is shaped at every control step based on the comparison of the average third octave noise spectrum, measured from a number of microphones in the test room, with the target spectrum. Cross-over filters split the output drive into band- limited signals to feed each of the horns. The control system is realized in several steps. In the first phase, a dynamic process model is developed, including the non-linear characteristics of the horns and the reverberant properties of the room. The model is identified from dynamic experiments using system identification techniques. In the next phase, an adequate control strategy is designed which is capable of reaching the target spectrum in the required time period without overshoots. This control strategy is obtained from model-in-the-loop (MIL) simulations, evaluating the performance of various potential strategies. Finally, the proposed strategy is

  1. Adaptive FTC based on Control Allocation and Fault Accommodation for Satellite Reaction Wheels

    OpenAIRE

    Baldi, P.; Blanke, Mogens; P. Castaldi; Mimmo, N.; S. Simani

    2016-01-01

    This paper proposes an active fault tolerant control scheme to cope with faults or failures affecting the flywheel spin rate sensors or satellite reaction wheel motors. The active fault tolerant control system consists of a fault detection and diagnosis module along with a control allocationand fault accommodation module directly exploiting the on-line fault estimates. The use of the nonlinear geometric approach and radial basis function neural networks allows to obtain a precise fault isolat...

  2. ARM Radiosondes for National Polar-Orbiting Operational Environmental Satellite System Preparatory Project Validation Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Borg, Lori [Univ. of Wisconsin, Madison, WI (United States); Tobin, David [Univ. of Wisconsin, Madison, WI (United States); Reale, Anthony [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Knuteson, Robert [Univ. of Wisconsin, Madison, WI (United States); Feltz, Michelle [Univ. of Wisconsin, Madison, WI (United States); Liu, Mark [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Holdridge, Donna J [Argonne National Lab. (ANL), Argonne, IL (United States); Mather, James [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-06-01

    This IOP has been a coordinated effort involving the U.S. Department of Energy (DOE) Atmospheric Radiation (ARM) Climate Research Facility, the University of Wisconsin (UW)-Madison, and the JPSS project to validate SNPP NOAA Unique Combined Atmospheric Processing System (NUCAPS) temperature and moisture sounding products from the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS). In this arrangement, funding for radiosondes was provided by the JPSS project to ARM. These radiosondes were launched coincident with the SNPP satellite overpasses (OP) at four of the ARM field sites beginning in July 2012 and running through September 2017. Combined with other ARM data, an assessment of the radiosonde data quality was performed and post-processing corrections applied producing an ARM site Best Estimate (BE) product. The SNPP targeted radiosondes were integrated into the NOAA Products Validation System (NPROVS+) system, which collocated the radiosondes with satellite products (NOAA, National Aeronautics and Space Administration [NASA], European Organisation for the Exploitation of Meteorological Satellites [EUMETSAT], Geostationary Operational Environmental Satellite [GOES], Constellation Observing System for Meteorology, Ionosphere, and Climate [COSMIC]) and Numerical Weather Prediction (NWP forecasts for use in product assessment and algorithm development. This work was a fundamental, integral, and cost-effective part of the SNPP validation effort and provided critical accuracy assessments of the SNPP temperature and water vapor soundings.

  3. 49 CFR 227.113 - Noise operational controls.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION OCCUPATIONAL NOISE EXPOSURE Occupational Noise Exposure for Railroad Operating Employees. § 227.113 Noise operational controls. (a) Railroads may use noise operational controls at any sound level to reduce exposures to levels below those required by Table A-1 of appendix A...

  4. 30 CFR 56.6300 - Control of blasting operations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of blasting operations. 56.6300 Section... § 56.6300 Control of blasting operations. (a) Only persons trained and experienced in the handling and use of explosive material shall direct blasting operations and related activities. (b) Trainees...

  5. 30 CFR 57.6300 - Control of blasting operations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of blasting operations. 57.6300 Section... Transportation-Surface and Underground § 57.6300 Control of blasting operations. (a) Only persons trained and experienced in the handling and use of explosive material shall direct blasting operations and...

  6. Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty

    Science.gov (United States)

    Wu, Shunan; Liu, Yufei; Radice, Gianmarco; Tan, Shujun

    2017-01-01

    With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna’s optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional–derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness. PMID:28287450

  7. Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty.

    Science.gov (United States)

    Wu, Shunan; Liu, Yufei; Radice, Gianmarco; Tan, Shujun

    2017-03-10

    With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna's optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional-derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness.

  8. Autonomous Pointing Control of a Large Satellite Antenna Subject to Parametric Uncertainty

    Directory of Open Access Journals (Sweden)

    Shunan Wu

    2017-03-01

    Full Text Available With the development of satellite mobile communications, large antennas are now widely used. The precise pointing of the antenna’s optical axis is essential for many space missions. This paper addresses the challenging problem of high-precision autonomous pointing control of a large satellite antenna. The pointing dynamics are firstly proposed. The proportional–derivative feedback and structural filter to perform pointing maneuvers and suppress antenna vibrations are then presented. An adaptive controller to estimate actual system frequencies in the presence of modal parameters uncertainty is proposed. In order to reduce periodic errors, the modified controllers, which include the proposed adaptive controller and an active disturbance rejection filter, are then developed. The system stability and robustness are analyzed and discussed in the frequency domain. Numerical results are finally provided, and the results have demonstrated that the proposed controllers have good autonomy and robustness.

  9. Multiagent Attitude Control System for Satellites Based in Momentum Wheels and Event-Driven Synchronization

    Science.gov (United States)

    Garcia, Juan L.; Moreno, Jose Sanchez

    2012-12-01

    Attitude control is a requirement always present in spacecraft design. Several kinds of actuators exist to accomplish this control, being momentum wheels one of the most employed. Usually satellites carry redundant momentum wheels to handle any possible single failure, but the controller remains as a single centralized element, posing problems in case of failures. In this work a decentralized agent-based event-driven algorithm for attitude control is presented as a possible solution. Several agents based in momentum wheels will interact among them to accomplish the satellite control. A simulation environment has been developed to analyze the behavior of this architecture. This environment has been made available through the web page http://www.dia.uned.es.

  10. Remote Operations and Ground Control Centers

    Science.gov (United States)

    Bryant, Barry S.; Lankford, Kimberly; Pitts, R. Lee

    2004-01-01

    The Payload Operations Integration Center (POIC) at the Marshall Space Flight Center supports the International Space Station (ISS) through remote interfaces around the world. The POIC was originally designed as a gateway to space for remote facilities; ranging from an individual user to a full-scale multiuser environment. This achievement was accomplished while meeting program requirements and accommodating the injection of modern technology on an ongoing basis to ensure cost effective operations. This paper will discuss the open POIC architecture developed to support similar and dissimilar remote operations centers. It will include technologies, protocols, and compromises which on a day to day basis support ongoing operations. Additional areas covered include centralized management of shared resources and methods utilized to provide highly available and restricted resources to remote users. Finally, the effort of coordinating the actions of participants will be discussed.

  11. Automatic phase control in solar power satellite systems

    Science.gov (United States)

    Lindsey, W. C.; Kantak, A. V.

    1978-01-01

    Various approaches to the problem of generating, maintaining and distributing a coherent, reference phase signal over a large area are suggested, mathematically modeled and analyzed with respect to their ability to minimize: phase build-up, beam diffusion and beam steering phase jitter, cable length, and maximize power transfer efficiency. In addition, phase control configurations are suggested which alleviate the need for layout symmetry.

  12. Communication and Control in the Canadian North: The Role of Interactive Satellites.

    Science.gov (United States)

    Valaskakis, Gail G.

    In 1972 the Canadian government launched its first domestic communications satellite, Anik A, which relays direct broadcast television and telephone messages to northern communities. The impact of television on Inuit life has raised issues and concerns pertaining to native language broadcasting, media access and control, and cultural identity…

  13. Solar attitude control including active nutation damping in a fixed-momentum wheel satellite

    Science.gov (United States)

    Azor, Ruth

    1992-08-01

    In geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances, caused mainly by solar pressure. This work presents a roll/yaw control, which is obtained by the use of solar arrays and fixed flaps as actuators, with a horizon sensor for roll measurement. The design also includes an active nutation damping.

  14. Lessons Learned from the Deployment and Integration of a Microwave Sounder Based Tropical Cyclone Intensity and Surface Wind Estimation Algorithm into NOAA/NESDIS Satellite Product Operations

    Science.gov (United States)

    Longmore, S. P.; Knaff, J. A.; Schumacher, A.; Dostalek, J.; DeMaria, R.; Chirokova, G.; Demaria, M.; Powell, D. C.; Sigmund, A.; Yu, W.

    2014-12-01

    The Colorado State University (CSU) Cooperative Institute for Research in the Atmosphere (CIRA) has recently deployed a tropical cyclone (TC) intensity and surface wind radii estimation algorithm that utilizes Suomi National Polar-orbiting Partnership (S-NPP) satellite Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit (AMSU) from the NOAA18, NOAA19 and METOPA polar orbiting satellites for testing, integration and operations for the Product System Development and Implementation (PSDI) projects at NOAA's National Environmental Satellite, Data, and Information Service (NESDIS). This presentation discusses the evolution of the CIRA NPP/AMSU TC algorithms internally at CIRA and its migration and integration into the NOAA Data Exploitation (NDE) development and testing frameworks. The discussion will focus on 1) the development cycle of internal NPP/AMSU TC algorithms components by scientists and software engineers, 2) the exchange of these components into the NPP/AMSU TC software systems using the subversion version control system and other exchange methods, 3) testing, debugging and integration of the NPP/AMSU TC systems both at CIRA/NESDIS and 4) the update cycle of new releases through continuous integration. Lastly, a discussion of the methods that were effective and those that need revision will be detailed for the next iteration of the NPP/AMSU TC system.

  15. Dynamics and chaos control of asymmetric gyrostat satellites

    Science.gov (United States)

    Aslanov, V. S.; Yudintsev, V. V.

    2014-05-01

    The motion of a free gyrostat consisting of a platform with a triaxial ellipsoid of inertia and a rotor with a slight asymmetry with respect to the axis of rotation is considered. Dimensionless equations of motion for a system with perturbations caused by the small asymmetries of the rotor are written in Andoyer-Deprit variables. These perturbations result in a chaotic layer in the separatrix vicinity. Heteroclinic and homoclinic trajectories are written in analytical form for gyrostats with different ratios of their moments of inertia. These trajectories are used to construct a modified Melnikov function, and to produce control that eliminates separatrix chaos. The Poincare sections and Melnikov function are constructed via numerical modeling that demonstrates the effectiveness of control.

  16. Operational Strategy of CBPs for load balancing of Operators in Advanced Main Control Room

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seunghwan; Kim, Yochan; Jung, Wondea [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    With the using of a computer-based control room in an APR1400 (Advanced Pressurized Reactor-1400), the operators' behaviors in the main control room had changed. However, though the working environment of operators has been changed a great deal, digitalized interfaces can also change the cognitive tasks or activities of operators. First, a shift supervisor (SS) can confirm/check the conduction of the procedures and the execution of actions of board operators (BOs) while confirming directly the operation variables without relying on the BOs. Second, all operators added to their work the use of a new CBP and Soft Controls, increasing their procedural workload. New operational control strategies of CBPs are necessary for load balancing of operator's task load in APR1400. In this paper, we compared the workloads of operators in an APR1400 who work with two different usages of the CBP. They are SS oriented usage and SS-BO collaborative usage. In this research, we evaluated the workloads of operators in an advanced main control room by the COCOA method. Two types of CBP usages were defined and the effects of these usages on the workloads were investigated. The obtained results showed that the workloads between operators in a control room can be balanced according to the CBP usages by assigning control authority to the operators.

  17. Guidance, Navigation, and Control Techniques and Technologies for Active Satellite Removal

    Science.gov (United States)

    Ortega Hernando, Guillermo; Erb, Sven; Cropp, Alexander; Voirin, Thomas; Dubois-Matra, Olivier; Rinalducci, Antonio; Visentin, Gianfranco; Innocenti, Luisa; Raposo, Ana

    2013-09-01

    This paper shows an internal feasibility analysis to de- orbit a non-functional satellite of big dimensions by the Technical Directorate of the European Space Agency ESA. The paper focuses specifically on the design of the techniques and technologies for the Guidance, Navigation, and Control (GNC) system of the spacecraft mission that will capture the satellite and ultimately will de-orbit it on a controlled re-entry.The paper explains the guidance strategies to launch, rendezvous, close-approach, and capture the target satellite. The guidance strategy uses chaser manoeuvres, hold points, and collision avoidance trajectories to ensure a safe capture. It also details the guidance profile to de-orbit it in a controlled re-entry.The paper continues with an analysis of the required sensing suite and the navigation algorithms to allow the homing, fly-around, and capture of the target satellite. The emphasis is placed around the design of a system to allow the rendezvous with an un-cooperative target, including the autonomous acquisition of both the orbital elements and the attitude of the target satellite.Analysing the capture phase, the paper provides a trade- off between two selected capture systems: the net and the tentacles. Both are studied from the point of view of the GNC system.The paper analyses as well the advanced algorithms proposed to control the final compound after the capture that will allow the controlled de-orbiting of the assembly in a safe place in the Earth.The paper ends proposing the continuation of this work with the extension to the analysis of the destruction process of the compound in consecutive segments starting from the entry gate to the rupture and break up.

  18. Frequency Control for Island Operation of Bornholm Power System

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Wu, Qiuwei; Zhao, Haoran;

    2014-01-01

    This paper presents a coordinated control strategy of a battery energy storage system (BESS) and distributed generation (DG) units for the island operation of the Danish island of Bornholm. The Bornholm power system is able to transit from the grid connected operation with the Nordic power system...... the primary frequency control and the DG units are used to provide the secondary frequency control. As such, the proposed control scheme can strike a balance of the frequency control speed and the energy used from the BESS for the frequency control support. The real-time model of the Bornholm power system...... to the isolated island operation. In order to ensure the secure island operation, the coordinated control of the BESS and the DG has been proposed to stabilize the frequency of the system after the transition to the island operation. In the proposed coordinate control scheme, the BESS is used to provide...

  19. Analytical derivation and verification of zero-gyro control for the IUE satellite

    Science.gov (United States)

    Bowles, Tiffany; Croft, John

    1989-01-01

    The International Ultraviolet Explorer (IUE) satellite was launched January 26, 1978 into a geosynchronous orbit over South America. From its stationary position, the telescope maintains continuous communication with the control centers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and at the European Space Agency's (ESA's) Villagranca del Castillo Satellite Tracking Station in Spain. Since its launch in 1978, the satellite has gradually lost four of the original six gyroscopes in the Inertial Reference Assembly (IRA). In August 1985, the fourth of the original six gyros failed and a two-gyro system developed by NASA-GSFC was uplinked to the satellite and is currently in use. A one-gyro system also developed by NASA-GSFC is ready for use in case of another gyro failure. In the event that the sixth gyro should also fail, a zero-gyro system is being developed. The goal of this system is to provide interial target pointing without the use of gyroscopes. The satellite has sun sensors to provide attitude information about two of the three axes. It relies upon the exchange of reaction wheel momenta to determine angular position and rate of the third axis.

  20. An Open Specification for Space Project Mission Operations Control Architectures

    Science.gov (United States)

    Hooke, A.; Heuser, W. R.

    1995-01-01

    An 'open specification' for Space Project Mission Operations Control Architectures is under development in the Spacecraft Control Working Group of the American Institute for Aeronautics and Astro- nautics. This architecture identifies 5 basic elements incorporated in the design of similar operations systems: Data, System Management, Control Interface, Decision Support Engine, & Space Messaging Service.

  1. Experimental verification of chaotic control of an underactuated tethered satellite system

    Science.gov (United States)

    Pang, Zhaojun; Jin, Dongping

    2016-03-01

    This paper studies chaotic control of a tethered satellite system (TSS) driven only by a momentum-exchange device during its attitude adjustment. In dealing with such the underactuated system, an extended time-delay autosynchronization (ETDAS) is employed to stabilize the chaotic motion to a periodic motion. To obtain the control domains of the ETDAS method, a stability analysis of the controlled tethered satellite system in elliptical orbit is implemented. According to the principle of dynamic similarity, then, ground-based experiment setups are proposed and designed to emulate the in-plane motions of the TSS. Representative experiments are presented to demonstrate the effectiveness of the ETDAS scheme in controlling the chaotic motion of the underactuated TSS.

  2. Search for an eventual control of Saturnian kilometric radiation by Titan satellite

    Science.gov (United States)

    Boudjada, Mohammed Y.; Galopeau, Patrick H. M.; Lecacheux, Alain; Rucker, Helmut

    2013-04-01

    The Cassini Radio and Plasma Wave Science Experiment (RPWS) revealed prominent arcs when the data are displayed in time-frequency coordinates, in the so-called dynamic spectra. We show that the Saturnian Kilometric Radiation (SKR) presents different kinds of characteristic appearances like arc structures. Those arcs may be classified in two sets: the 'vertex early arcs' (VEA) and the 'vertex late arcs' (VLA), and are observed in the frequency range between 80 kHz and 1 MHz. We investigate the probable control of the SKR arcs by the Titan satellite. We emphasis in this study on the arc observational parameters (e.g. the probability of occurrence, the local time and the gyro-frequency) and their eventual relations to the geometrical configuration between Saturn, Titan, and the observed (i.e. Cassini spacecraft). We follow in this analysis a similar method applied to the control of Jovian decametric emissions by the Io satellite. This method consists principally to observe, on one side, the arc curvatures and their corresponding maximum frequency, and on the other side the orbital phase of the Titan satellite around the planet. This leads us to provide a first attempt concerning the 'controls' of non-thermal Jovian and Saturnian radio emissions, respectively, by Io and Titan satellites.

  3. Adaptive FTC based on Control Allocation and Fault Accommodation for Satellite Reaction Wheels

    DEFF Research Database (Denmark)

    Baldi, P.; Blanke, Mogens; Castaldi, P.;

    2016-01-01

    This paper proposes an active fault tolerant control scheme to cope with faults or failures affecting the flywheel spin rate sensors or satellite reaction wheel motors. The active fault tolerant control system consists of a fault detection and diagnosis module along with a control allocation...... estimation filters, which do not need a priori information about the internal model of the signal to be estimated. The adaptive control allocation and sensor fault accommodation can handle both temporal faults and failures. Simulation results illustrate the convincing fault correction and attitude control...

  4. Fuzzy Control Strategies in Human Operator and Sport Modeling

    CERN Document Server

    Ivancevic, Tijana T; Markovic, Sasa

    2009-01-01

    The motivation behind mathematically modeling the human operator is to help explain the response characteristics of the complex dynamical system including the human manual controller. In this paper, we present two different fuzzy logic strategies for human operator and sport modeling: fixed fuzzy-logic inference control and adaptive fuzzy-logic control, including neuro-fuzzy-fractal control. As an application of the presented fuzzy strategies, we present a fuzzy-control based tennis simulator.

  5. Deploying process modeling and attitude control of a satellite with a large deployable antenna

    OpenAIRE

    Zhigang Xing; Gangtie Zheng

    2014-01-01

    Modeling and attitude control methods for a satellite with a large deployable antenna are studied in the present paper. Firstly, for reducing the model dimension, three dynamic models for the deploying process are developed, which are built with the methods of multi-rigid-body dynamics, hybrid coordinate and substructure. Then an attitude control method suitable for the deploying process is proposed, which can keep stability under any dynamical parameter variation. Subsequently, this attitude...

  6. Solar sail attitude control including active nutation damping in a fixed-momentum wheel satellite

    Science.gov (United States)

    Azor, Ruth

    1992-02-01

    In the geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances caused by solar radiation pressure. This work presents a roll/yaw control system with a horizon sensor for roll measurement. Roll/yaw control is obtained by the use of solar arrays and fixed flaps as actuators. The design also includes an active nutation damping method.

  7. Simple operated multipurpose temperature control cryostat

    Institute of Scientific and Technical Information of China (English)

    ABBAS T.A.; OMAR M.S.

    2007-01-01

    A suitable simple optical cryostat for optical, magneto-optical, electrical and thermo-electrical measurements was designed. It is suitable for use in a magnetic pool gap as narrow as less than 1 cm. Throughout a long period of time, the heat diffusion process of the cryostat can be easily operated at slow increase in sample temperature in a range 1.25 K/min at 200 K that will be reduced gradually to 0.66 K at room temperature. Liquid nitrogen was used to cool down the temperature. During the operation, the change in the measured energy gap of a semiconductor sample and other physical parameters resulting from the change of temperature can be corrected through the temperature coefficient of that parameter at the corresponding temperature.The cryostat was successfully used for all experiments mentioned above to measure the properties of a single crystal of GaP (Gallium Phosphate) semiconductor.

  8. Contamination Control for Scientific Drilling Operations.

    Science.gov (United States)

    Kallmeyer, J

    2017-01-01

    Drilling is an integral part of subsurface exploration. Because almost all drilling operations require the use of a drill fluid, contamination by infiltration of drill fluid into the recovered core material cannot be avoided. Because it is impossible to maintain sterile conditions during drilling the drill fluid will contain surface microbes and other contaminants. As contamination cannot be avoided, it has to be tracked to identify those parts of the drill core that were not infiltrated by the drill fluid. This is done by the addition of tracer compounds. A great variety of tracers is available, and the choice depends on many factors. This review will first explain the basic principles of drilling before presenting the most common tracers and discussing their strengths and weaknesses. The final part of this review presents a number of key questions that have to be addressed in order to find the right tracer for a particular drilling operation.

  9. A satellite digital controller or 'play that PID tune again, Sam'. [Position, Integral, Derivative feedback control algorithm for design strategy

    Science.gov (United States)

    Seltzer, S. M.

    1976-01-01

    The problem discussed is to design a digital controller for a typical satellite. The controlled plant is considered to be a rigid body acting in a plane. The controller is assumed to be a digital computer which, when combined with the proposed control algorithm, can be represented as a sampled-data system. The objective is to present a design strategy and technique for selecting numerical values for the control gains (assuming position, integral, and derivative feedback) and the sample rate. The technique is based on the parameter plane method and requires that the system be amenable to z-transform analysis.

  10. Visual operations control in administrative environments

    Energy Technology Data Exchange (ETDEWEB)

    Carson, M.L.; Levine, L.O.

    1995-03-01

    When asked what comes to mind when they think of ``controlling work`` in the office, people may respond with ``overbearing boss,`` ``no autonomy,`` or ``Theory X management.`` The idea of controlling work in white collar or administrative environments can have a negative connotation. However, office life is often chaotic and miserable precisely because the work processes are out of control, and managers must spend their time looking over people`s shoulders and fighting fires. While management styles and structures vary, the need for control of work processes does not. Workers in many environments are being reorganized into self-managed work teams. These teams are expected to manage their own work through increased autonomy and empowerment. However, even empowered work teams must manage their work processes because of process variation. The amount of incoming jobs vary with both expected (seasonal) and unexpected demand. The mixture of job types vary over time, changing the need for certain skills or knowledge. And illness and turnover affect the availability of workers with needed skills and knowledge. Clearly, there is still a need to control work, whether the authority for controlling work is vested in one person or many. Visual control concepts provide simple, inexpensive, and flexible mechanisms for managing processes in work teams and continuous improvement administrative environments.

  11. Next Generation Operational Control System (OCX)

    Science.gov (United States)

    2015-12-01

    UNCLASSIFIED 5 Mission and Description The Global Positioning System (GPS) is a space-based positioning, navigation, and timing distribution system, which...operates through weather and electromagnetic environments (jamming, spoofing, etc.). GPS supports both civil and military users in air, space, sea, and...a complex incentive structure; and high government personnel turnover. The Program Office and Raytheon have worked to address the root causes

  12. Networks systems and operations. [wideband communication techniques for data links with satellites

    Science.gov (United States)

    1975-01-01

    The application of wideband communication techniques for data links with satellites is discussed. A diagram of the demand assigned voice communications system is provided. The development of prototype integrated spacecraft paramps at S- and C-bands is described and the performance of space-qualified paramps is tabulated. The characteristics of a dual parabolic cylinder monopulse zoom antenna for use with the tracking and data relay satellite system (TDRSS) are analyzed. The development of a universally applicable transponder at S-band is reported. A block diagram of the major subassemblies of the S-band transponder is included. The technology aspects of network timing and synchronization of communication systems are to show the use of the Omega navigation system. The telemetry data compression system used during the Skylab program is evaluated.

  13. SARSAT (Search and Rescue Satellite) Operational Data Categorization and Accuracy Studies.

    Science.gov (United States)

    1985-09-01

    poursuite terrestre SARSAT jusqu’aux usagers du systime de recherche et de sauvetage opgrationnels influe de faqon importante sur le succis qu’auront...or an Emergency Position Indicating Radio Beacon (EPIRB), is detected by a polar- orbiting spacecraft equipped with suitable receive.-s. Such signals...positioning performance, satellites in a low-altitude polar orbit are used. The low altitude results in low ELT/EPIRB power requirements, good Doppler-shift

  14. Dynamical modelling and control of a spacecraft-mounted manipulator capturing a spinning satellite

    Science.gov (United States)

    Cyril, Xavier; Jaar, Gilbert J.; Misra, Arun K.

    1995-01-01

    Issues associated with the modelling and control of a spacecraft-mounted manipulator capturing a spinning satellite are presented. The Lagrangian formulation is used to derive the dynamical equations of the system immediately following the capture. The formulation is carried out by writing Lagrange's equations for the individual bodies, and then assembling them to obtain the constrained dynamical equations of the system. The non-working constraint forces/torques are then eliminated by using the natural orthogonal complement which produces a set of independent dynamical equations. A control algorithm whose objective is to produce a set of feedback-linearized, homogeneous and uncoupled equations is designed and implemented. The initial conditions of the state variables needed to achieve smooth berthing of the satellite are computed, and the dynamics simulation of both the controlled and uncontrolled systems is carried out. The manipulator's structural flexibility is included in the dynamics simulation model.

  15. Design of Air Traffic Control Operation System

    Directory of Open Access Journals (Sweden)

    Gabriela STROE

    2017-09-01

    Full Text Available This paper presents a numerical simulation for a different aircraft, based on the specific aircraft data that can be incorporated in the model and the equations of motions which can be consequently solved. The aircraft flight design involves various technical steps and requires the use of sophisticated software having modeling and simulation capabilities. Within the flight simulation model, the aerodynamic model can be regarded as the most complex and most important. With appropriate aerodynamic modeling the aerodynamic forces and moments acting on the aircraft's center of gravity can be numerically solved with accuracy. These forces and moments are further used to solve the equations of motion. The development of control and computing technology makes it possible for advanced flight control strategy. The advanced control techniques tend to make the control design and their implementation much more complicated with more control loops or channels; in this line, the autopilot of modern aircrafts includes a variety of automatic control systems that aid and support the flight navigation, flight management, and perform the enhancing and/or augmenting of the stability characteristics of the airplane. Therefore in this context it is very important to choose the dynamic that will satisfy the performance and robustness specifications.

  16. A modeling and simulation of control system of satellite tracking platform an- tenna

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaojun; GONG Lihong

    2012-01-01

    Based on the platform of mobile carrier satellite tracking has a wide range of applications. The paper adopts the advanced method of to step response identify, using the data obtained by the experiment model of high-speed acquisition, using the method of the least squares, finally the antenna control system model function was identified. Make use of integral separation algorithm, simu- link simulation and experiment analysis to set the control parameters of it. Stimulate the signal antenna control system under inter- fering. The experiment of the simulation experiment showed that the antenna control system model is stable with little error.

  17. Orbit and Attitude Control of Asymmetric Satellites in Polar Near-Circular Orbit

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2009-10-01

    Full Text Available In this paper, the general problem about the orbit and attitude dynamic model is discussed. A feedback linearization control method is introduced for this model. Due to the asymmetric structure, the orbital properties of such satellites are the same as traditional symmetric ones, but the attitude properties are greatly different from the symmetric counterparts. With perturbations accumulate with time, the attitude angles increase periodically with time, but the orbital elements change much slower than the attitude angles. In the attitude dynamic model, chaos could appear. Traditional linear controllers can not compensate enough for asymmetric satellite when the mission is complex, especially in maneuver missions. Thus nonlinear control method is required to solve such problem in large scale. A feedback linearization method, one robust nonlinear control method, is introduced and applied to the asymmetric satellite in this paper. Some simulations are also given and the results show that feedback linearization controller not only stabilizes the system, but also exempt the chaos in the system.

  18. Post operative pain control in inguinal hernia repair: comparison of ...

    African Journals Online (AJOL)

    Post operative pain control in inguinal hernia repair: comparison of tramadol versus ... Log in or Register to get access to full text downloads. ... postoperative pain control effects and cost effectiveness of Tramadol versus Bupivaaine in wound ...

  19. MITRA Virtual laboratory for operative application of satellite time series for land degradation risk estimation

    Science.gov (United States)

    Nole, Gabriele; Scorza, Francesco; Lanorte, Antonio; Manzi, Teresa; Lasaponara, Rosa

    2015-04-01

    This paper aims to present the development of a tool to integrate time series from active and passive satellite sensors (such as of MODIS, Vegetation, Landsat, ASTER, COSMO, Sentinel) into a virtual laboratory to support studies on landscape and archaeological landscape, investigation on environmental changes, estimation and monitoring of natural and anthropogenic risks. The virtual laboratory is composed by both data and open source tools specifically developed for the above mentioned applications. Results obtained for investigations carried out using the implemented tools for monitoring land degradation issues and subtle changes ongoing on forestry and natural areas are herein presented. In detail MODIS, SPOT Vegetation and Landsat time series were analyzed comparing results of different statistical analyses and the results integrated with ancillary data and evaluated with field survey. The comparison of the outputs we obtained for the Basilicata Region from satellite data analyses and independent data sets clearly pointed out the reliability for the diverse change analyses we performed, at the pixel level, using MODIS, SPOT Vegetation and Landsat TM data. Next steps are going to be implemented to further advance the current Virtual Laboratory tools, by extending current facilities adding new computational algorithms and applying to other geographic regions. Acknowledgement This research was performed within the framework of the project PO FESR Basilicata 2007/2013 - Progetto di cooperazione internazionale MITRA "Remote Sensing tecnologies for Natural and Cultural heritage Degradation Monitoring for Preservation and valorization" funded by Basilicata Region Reference 1. A. Lanorte, R Lasaponara, M Lovallo, L Telesca 2014 Fisher-Shannon information plane analysis of SPOT/VEGETATION Normalized Difference Vegetation Index (NDVI) time series to characterize vegetation recovery after fire disturbance International Journal of Applied Earth Observation and

  20. Boiler Control Systems Theory of Operation Manual.

    Science.gov (United States)

    1983-02-01

    9 lfeduce!s routine mtainltenance N through use of bitilt-in air 4up- *,1 ilternd, ltain eisa e Simplifie.. stockintg of -.pare - parto -illre uuanyv...operation pushbuttons and two-position transfer switch. The vertical meter is a I.5v voltmeter scaled 0-ICO representing percent of the nput M vanal-le. The...by the ratio dial seting. Ie 002 Pr aie Set Satieson, curren output. Vertices ale ndiceerds*o ea tof the Storin pae atF iei signel. 1 T1wred i 22A

  1. Expert operator preferences in remote manipulator control systems

    Energy Technology Data Exchange (ETDEWEB)

    Sundstrom, E. [Human Machine Interfaces, Inc., Knoxville, TN (United States); Draper, J.V. [Oak Ridge National Lab., TN (United States); Fausz, A.; Woods, H. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-06-01

    This report describes a survey of expert remote manipulator operators designed to identify features of control systems related to operator efficiency and comfort. It provides information for designing the control center for the Single-Shell Tank Waste Retrieval Manipulator System (TWRMS) Test Bed, described in a separate report. Research questions concerned preferred modes of control, optimum work sessions, sources of operator fatigue, importance of control system design features, and desired changes in control rooms. Participants comprised four expert remote manipulator operators at Oak Ridge National Laboratory, who individually have from 9 to 20 years of experience using teleoperators. The operators had all used rate and position control, and all preferred bilateral (force-reflecting) position control. They reported spending an average of 2.75 h in control of a teleoperator system during a typical shift. All were accustomed to working in a crew of two and alternating control and support roles in 2-h rotations in an 8-h shift. Operators reported that fatigue in using remote manipulator systems came mainly from watching TV monitors and making repetitive motions. Three of four experienced symptoms, including headaches and sore eyes, wrists, and back. Of 17 features of control rooms rated on importance, highest ratings went to comfort and support provided by the operator chair, location of controls, location of video monitors, video image clarity, types of controls, and control modes. When asked what they wanted to change, operators said work stations designed for comfort; simpler, lighter hand-controls; separate controls for each camera; better placement of remote camera; color monitors; and control room layouts that support crew interaction. Results of this small survey reinforced the importance of ergonomic factors in remote manipulation.

  2. Monitored Geologic Repository Operations Monitoring and Control System Description Document

    Energy Technology Data Exchange (ETDEWEB)

    E.F. Loros

    2000-06-29

    The Monitored Geologic Repository Operations Monitoring and Control System provides supervisory control, monitoring, and selected remote control of primary and secondary repository operations. Primary repository operations consist of both surface and subsurface activities relating to high-level waste receipt, preparation, and emplacement. Secondary repository operations consist of support operations for waste handling and treatment, utilities, subsurface construction, and other selected ancillary activities. Remote control of the subsurface emplacement operations, as well as, repository performance confirmation operations are the direct responsibility of the system. In addition, the system monitors parameters such as radiological data, air quality data, fire detection status, meteorological conditions, unauthorized access, and abnormal operating conditions, to ensure a safe workplace for personnel. Parameters are displayed in a real-time manner to human operators regarding surface and subsurface conditions. The system performs supervisory monitoring and control for both important to safety and non-safety systems. The system provides repository operational information, alarm capability, and human operator response messages during emergency response situations. The system also includes logic control to place equipment, systems, and utilities in a safe operational mode or complete shutdown during emergency response situations. The system initiates alarms and provides operational data to enable appropriate actions at the local level in support of emergency response, radiological protection response, evacuation, and underground rescue. The system provides data communications, data processing, managerial reports, data storage, and data analysis. This system's primary surface and subsurface operator consoles, for both supervisory and remote control activities, will be located in a Central Control Center (CCC) inside one of the surface facility buildings. The system

  3. Construction robot force control in cleaning operations

    Science.gov (United States)

    Zhou, Y.; Skibniewski, M. J.

    1994-01-01

    Basic surface treatment tasks on construction sites that can be performed by robots include the spraying, cleaning, and finishing of surfaces. In the present paper, a construction robot is proposed for accomplishing a variety of cleaning tasks in construction. Specifically, the force-control problem in cleaning a surface is studied. The paper shows that a force sensor can be used not only to monitor the force acting at the contact points, but also to identify the uncertainties of the unstructured construction environment. A different formulation for the external force is presented. With this formulation, the external force on the end-effector is presented as a function of the contact force, contact torque, and constraint conditions, but not the actuated torque in the joint space. Therefore, the force-control problem is simplified to compensate for the external force and to exert a desired force. One advantage fo this approach is that the original PID position control loop of an industrial robot is retained so that the time-consuming computed torque method is avoided. The proposed control scheme can be applied to numerous cleaning tasks with hard contact regardless of the different nature of the surface.

  4. 47 CFR 90.473 - Operation of internal transmitter control systems through licensed fixed control points.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operation of internal transmitter control... Transmitter Control Internal Transmitter Control Systems § 90.473 Operation of internal transmitter control systems through licensed fixed control points. An internal transmitter control system may be...

  5. Utilizing Robot Operating System (ROS) in Robot Vision and Control

    Science.gov (United States)

    2015-09-01

    OPERATING SYSTEM (ROS) IN ROBOT VISION AND CONTROL by Joshua S. Lum September 2015 Thesis Advisor: Xiaoping Yun Co-Advisor: Zac Staples...Master’s Thesis 4. TITLE AND SUBTITLE UTILIZING ROBOT OPERATING SYSTEM (ROS) IN ROBOT VISION AND CONTROL 5. FUNDING NUMBERS 6. AUTHOR(S) Lum, Joshua S...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) The Robot Operating System (ROS) is an open-source framework that allows robot developers to create

  6. Attitude and vibration control of a satellite containing flexible solar arrays by using reaction wheels, and piezoelectric transducers as sensors and actuators

    Science.gov (United States)

    da Fonseca, Ijar M.; Rade, Domingos A.; Goes, Luiz C. S.; de Paula Sales, Thiago

    2017-10-01

    The primary purpose of this paper is to provide insight into control-structure interaction for satellites comprising flexible appendages and internal moving components. The physical model considered herein aiming to attend such purpose is a rigid-flexible satellite consisting of a rigid platform containing two rotating flexible solar panels. The solar panels rotation is assumed to be in a sun-synchronous configuration mode. The panels contain surface-bonded piezoelectric patches that can be used either as sensors for the elastic displacements or as actuators to counteract the vibration motion. It is assumed that in the normal mode operation the satellite platform points towards the Earth while the solar arrays rotate so as to follow the Sun. The vehicle moves in a low Earth polar orbit. The technique used to obtain the mathematical model combines the Lagrangian formulation with the Finite Elements Method used to describe the dynamics of the solar panel. The gravity-gradient torque as well as the torque due to the interaction of the Earth magnetic field and the satellite internal residual magnetic moment is included as environmental perturbations. The actuators are three reaction wheels for attitude control and piezoelectric actuators to control the flexible motion of the solar arrays. Computer simulations are performed using the MATLAB® software package. The following on-orbit satellite operating configurations are object of analysis: i) Satellite pointing towards the Earth (Earth acquisition maneuver) by considering the initial conditions in the elastic displacement equal to zero, aiming the assessment of the flexible modes excitation by the referred maneuver; ii) the satellite pointing towards the Earth with the assumption of an initial condition different from zero for the flexible motion such that the attitude alterations are checked against the elastic motion disturbance; and iii) attitude acquisition accomplished by taking into account initial conditions

  7. Research on Canal System Operation Based on Controlled Volume Method

    Directory of Open Access Journals (Sweden)

    Zhiliang Ding

    2009-10-01

    Full Text Available An operating simulation mode based on storage volume control method for multireach canal system in series was established. In allusion to the deficiency of existing controlled volume algorithm, the improved algorithm was proposed, that is the controlled volume algorithm of whole canal pools, the simulation results indicate that the storage volume and water level of each canal pool can be accurately controlled after the improved algorithm was adopted. However, for some typical discharge demand change operating conditions of canal, if the controlled volume algorithm of whole canal pool is still adopted, then it certainly will cause some unnecessary regulation, and consequently increases the disturbed canal reaches. Therefor, the idea of controlled volume operation method of continuous canal pools was proposed, and its algorithm was designed. Through simulation to practical project, the results indicate that the new controlled volume algorithm proposed for typical operating condition can comparatively obviously reduce the number of regulated check gates and disturbed canal pools for some typical discharge demand change operating conditions of canal, thus the control efficiency of canal system was improved. The controlled volume method of operation is specially suitable for large-scale water delivery canal system which possesses complex operation requirements.

  8. Design Considerations for Miniaturized Control Moment Gyroscopes for Rapid Retargeting and Precision Pointing of Small Satellites

    Science.gov (United States)

    Patankar, Kunal; Fitz-Coy, Norman; Roithmayr, Carlos M.

    2014-01-01

    This paper presents the design as well as characterization of a practical control moment gyroscope (CMG) based attitude control system (ACS) for small satellites in the 15-20 kilogram mass range performing rapid retargeting and precision pointing maneuvers. The paper focuses on the approach taken in the design of miniaturized CMGs while considering the constraints imposed by the use of commercial off-the-shelf (COTS) components as well as the size of the satellite. It is shown that a hybrid mode is more suitable for COTS based moment exchange actuators; a mode that uses the torque amplification of CMGs for rapid retargeting and direct torque capabilities of the flywheel motors for precision pointing. A simulation is provided to demonstrate on-orbit slew and pointing performance.

  9. Optimality of incompletely measurable active and passive attitude control systems. [for satellites

    Science.gov (United States)

    Schiehlen, W.; Popp, K.

    1973-01-01

    Passive attitude control systems and active systems with incomplete state measurements are only suboptimal systems in the sense of optimal control theory, since optimal systems require complete state measurements or state estimations. An optimal system, then, requires additional hardware (especially in the case of flexible spacecraft) which results in higher costs. Therefore, it is a real engineering problem to determine how much an optimal system exceeds the suboptimal system, or in other words, what is the suboptimal system's degree of optimality. The problem will be treated in three steps: (1) definition of the degree of optimality for linear, time-invariant systems; (2) a computation method using the quadratic cost functional; (3) application to a gravity-gradient stabilized three-body satellite and a spinning flexible satellite.

  10. CONTACT: An Air Force technical report on military satellite control technology

    Science.gov (United States)

    Weakley, Christopher K.

    1993-07-01

    This technical report focuses on Military Satellite Control Technologies and their application to the Air Force Satellite Control Network (AFSCN). This report is a compilation of articles that provide an overview of the AFSCN and the Advanced Technology Program, and discusses relevant technical issues and developments applicable to the AFSCN. Among the topics covered are articles on Future Technology Projections; Future AFSCN Topologies; Modeling of the AFSCN; Wide Area Communications Technology Evolution; Automating AFSCN Resource Scheduling; Health & Status Monitoring at Remote Tracking Stations; Software Metrics and Tools for Measuring AFSCN Software Performance; Human-Computer Interface Working Group; Trusted Systems Workshop; and the University Technical Interaction Program. In addition, Key Technology Area points of contact are listed in the report.

  11. Attitude Control Synthesis for Small Satellites Using Gradient Method. Part I - Nonlinear Equations

    Directory of Open Access Journals (Sweden)

    Teodor-Viorel CHELARU

    2012-12-01

    Full Text Available The paper presents some aspects for synthesis of small satellites attitude control. Thesatellite nonlinear model presented here will be with six degrees of freedom. After movement equationlinearization the stability and command matrixes will be established and the controller will beobtained using gradient and gradient method. Two attitude control cases will be analysed: thereaction wheels and the micro thrusters. The results will be used in the project European Space MoonOrbit - ESMO founded by European Space Agency in which the University POLITEHNICA ofBucharest is involved.

  12. Attitude Control Synthesis for Small Satellites Using Gradient Method. Part II Linear Equations, Synthesis

    Directory of Open Access Journals (Sweden)

    Adrian CHELARU

    2013-03-01

    Full Text Available In order to continue paper [5] which presented the nonlinear equations of the movement for small satellite, this paper presents some aspects regarding the synthesis of the attitude control. Afterthe movement equation linearization, the stability and command matrixes will be established and by using the gradient methods controller we will obtain them. Two attitude control cases will beanalysed: the reaction wheels and the micro thrusters. The results will be used in the project European Space Moon Orbit - ESMO, founded by the European Space Agency in which the POLITEHNICA University of Bucharest is involved.

  13. The Use of a Satellite Communications System for Command and Control of the National Aeronautics and Space Administration Surrogate Unmanned Aerial System Research Aircraft

    Science.gov (United States)

    Howell, Charles T.; Jones, Frank; Hutchinson, Brian; Joyce, Claude; Nelson, Skip; Melum, Mike

    2017-01-01

    The NASA Langley Research Center has transformed a Cirrus Design SR22 general aviation (GA) aircraft into an Unmanned Aerial Systems (UAS) Surrogate research aircraft which has served for several years as a platform for unmanned systems research and development. The aircraft is manned with a Safety Pilot and a Research Systems Operator (RSO) that allows for flight operations almost any-where in the national airspace system (NAS) without the need for a Federal Aviation Administration (FAA) Certificate of Authorization (COA). The UAS Surrogate can be remotely controlled from a modular, transportable ground control station (GCS) like a true UAS. Ground control of the aircraft is accomplished by the use of data links that allow the two-way passage of the required data to control the aircraft and provide the GCS with situational awareness. The original UAS Surrogate data-link system was composed of redundant very high frequency (VHF) data radio modems with a maximum range of approximately 40 nautical miles. A new requirement was developed to extend this range beyond visual range (BVR). This new requirement led to the development of a satellite communications system that provided the means to command and control the UAS Surrogate at ranges beyond the limits of the VHF data links. The system makes use of the Globalstar low earth orbit (LEO) satellite communications system. This paper will provide details of the development, implementation, and flight testing of the satellite data communications system on the UAS Surrogate research aircraft.

  14. Understanding satellite-based monthly-to-seasonal reservoir outflow estimation as a function of hydrologic controls

    Science.gov (United States)

    Bonnema, Matthew; Sikder, Safat; Miao, Yabin; Chen, Xiaodong; Hossain, Faisal; Ara Pervin, Ismat; Mahbubur Rahman, S. M.; Lee, Hyongki

    2016-05-01

    Growing population and increased demand for water is causing an increase in dam and reservoir construction in developing nations. When rivers cross international boundaries, the downstream stakeholders often have little knowledge of upstream reservoir operation practices. Satellite remote sensing in the form of radar altimetry and multisensor precipitation products can be used as a practical way to provide downstream stakeholders with the fundamentally elusive upstream information on reservoir outflow needed to make important and proactive water management decisions. This study uses a mass balance approach of three hydrologic controls to estimate reservoir outflow from satellite data at monthly and annual time scales: precipitation-induced inflow, evaporation, and reservoir storage change. Furthermore, this study explores the importance of each of these hydrologic controls to the accuracy of outflow estimation. The hydrologic controls found to be unimportant could potentially be neglected from similar future studies. Two reservoirs were examined in contrasting regions of the world, the Hungry Horse Reservoir in a mountainous region in northwest U.S. and the Kaptai Reservoir in a low-lying, forested region of Bangladesh. It was found that this mass balance method estimated the annual outflow of both reservoirs with reasonable skill. The estimation of monthly outflow from both reservoirs was however less accurate. The Kaptai basin exhibited a shift in basin behavior resulting in variable accuracy across the 9 year study period. Monthly outflow estimation from Hungry Horse Reservoir was compounded by snow accumulation and melt processes, reflected by relatively low accuracy in summer and fall, when snow processes control runoff. Furthermore, it was found that the important hydrologic controls for reservoir outflow estimation at the monthly time scale differs between the two reservoirs, with precipitation-induced inflow being the most important control for the Kaptai

  15. Nonlinear Predictive Control for PEMFC Stack Operation Temperature

    Institute of Scientific and Technical Information of China (English)

    LI Xi; CAO Guang-yi; ZHU Xin-jian

    2005-01-01

    Operating temperature of proton exchange membrane fuel cell stack should be controlled within a special range. The input-output data and operating experiences were used to establish a PEMFC stack model and operating temperature control system. A nonlinear predictive control algorithm based on fuzzy model was presented for a family of complex system with severe nonlinearity such as PEMFC. Based on the obtained fuzzy model, a discrete optimization of the control action was carried out according to the principle of Branch and Bound method. The test results demonstrate the effectiveness and advantage of this approach.

  16. Satellite-based assessment of climate controls on US burned area

    OpenAIRE

    D. C. Morton; G. J. Collatz; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2013-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate–fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burne...

  17. Wildland fire management. Volume 2: Wildland fire control 1985-1995. [satellite information system for California fire problems

    Science.gov (United States)

    Saveker, D. R. (Editor)

    1973-01-01

    The preliminary design of a satellite plus computer earth resources information system is proposed for potential uses in fire prevention and control in the wildland fire community. Suggested are satellite characteristics, sensor characteristics, discrimination algorithms, data communication techniques, data processing requirements, display characteristics, and costs in achieving the integrated wildland fire information system.

  18. Semi-active Attitude Control and Off-line Attitude Determination for the SEETI-Express Student Micro-satellite

    DEFF Research Database (Denmark)

    Alminde, Lars

    This paper concerns the development of the Attitude Determination and Control System (ADCS) for the SSETI-Express micro-satellite mission. The mission is an educational project involving 14 universities and the European Space Agency (ESA). The satellite has been designed and built, by students...

  19. Semi-active Attitude Control and Off-line Attitude Determination for the SSETI-Express Student Micro-satellite

    DEFF Research Database (Denmark)

    Alminde, Lars

    2005-01-01

    This paper concerns the development of the Attitude Determination and Control System (ADCS) for the SSETI-Express micro-satellite mission. The mission is an educational project involving 14 universities and the European Space Agency (ESA). The satellite has been designed and built, by students...

  20. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    Science.gov (United States)

    Pepin, Gerard R.

    1992-01-01

    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  1. Coastal ocean research in sub-Saharan Africa: towards operational oceanography using satellites, in situ measurements and numerical models

    Science.gov (United States)

    Shillington, Frank

    Sub-Saharan Africa is greatly influenced by major western boundary currents of the Indian Ocean, Agulhas Current and the Somali Current (for six months of the year), and the major eastern boundary upwelling current systems of the Atlantic Ocean, with their concomitant nu-trient rich upwelling ecosystems which support large fisheries: the Benguela Upwelling System and the Canary Upwelling System. The location of the tip of placecountry-regionSouth Africa is unique in the world oceans, since it is such the only place where a warm western boundary current can interact with a cold upwelling ecosystem. In addition, the Agulhas Current is unique in that it retroflects 80% of its large volume flux back into the placeIndian Ocean. The interocean transport of warm thermocline water from the Indian to the placeAtlantic ocean is of global importance. Satellite observations of temperature, chlorophyll, sea surface height, and wind and waves have elucidated many of these first order processes. Numerical ocean models forced and constrained by satellite measurements are being increasingly used to place operational oceanography on a sound footing. Partnerships with African and northern hemisphere collaborators (e.g. the new Norwegian Nansen-Tutu Centre for Marine Research, PlaceNamePrinceton PlaceTypeUniversity) will enhance operational oceanography around placeAfrica to the benefit of all its inhabitants. All of the above aspects will be discussed, with specific examples of local innovative space borne techniques.

  2. Mapping Neglected Swimming Pools from Satellite Data for Urban Vector Control

    Science.gov (United States)

    Barker, C. M.; Melton, F. S.; Reisen, W. K.

    2010-12-01

    Neglected swimming pools provide suitable breeding habit for mosquitoes, can contain thousands of mosquito larvae, and present both a significant nuisance and public health risk due to their inherent proximity to urban and suburban populations. The rapid increase and sustained rate of foreclosures in California associated with the recent recession presents a challenge for vector control districts seeking to identify, treat, and monitor neglected pools. Commercial high resolution satellite imagery offers some promise for mapping potential neglected pools, and for mapping pools for which routine maintenance has been reestablished. We present progress on unsupervised classification techniques for mapping both neglected pools and clean pools using high resolution commercial satellite data and discuss the potential uses and limitations of this data source in support of vector control efforts. An unsupervised classification scheme that utilizes image segmentation, band thresholds, and a change detection approach was implemented for sample regions in Coachella Valley, CA and the greater Los Angeles area. Comparison with field data collected by vector control personal was used to assess the accuracy of the estimates. The results suggest that the current system may provide some utility for early detection, or cost effective and time efficient annual monitoring, but additional work is required to address spectral and spatial limitations of current commercial satellite sensors for this purpose.

  3. Modeling and Control for Islanding Operation of Active Distribution Systems

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Wu, Qiuwei; Saleem, Arshad

    2011-01-01

    Along with the increasing penetration of distributed generation (DG) in distribution systems, there are more resources for system operators to improve the operation and control of the whole system and enhance the reliability of electricity supply to customers. The distribution systems with DG...... are able to operate in is-landing operation mode intentionally or unintentionally. In order to smooth the transition from grid connected operation to islanding operation for distribution systems with DG, a multi-agent based controller is proposed to utilize different re-sources in the distribution systems...... to stabilize the frequency. Different agents are defined to represent different resources in the distribution systems. A test platform with a real time digital simulator (RTDS), an OPen Connectivity (OPC) protocol server and the multi-agent based intelligent controller is established to test the proposed multi...

  4. Control of Exciton Dynamics in Nanodots for Quantum Operations

    Science.gov (United States)

    Chen, Pochung; Piermarocchi, C.; Sham, L. J.

    2001-08-01

    We present a theory to further a new perspective of proactive control of exciton dynamics in the quantum limit. Circularly polarized optical pulses in a semiconductor nanodot are used to control the dynamics of two interacting excitons of opposite polarizations. Shaping of femtosecond laser pulses keeps the quantum operation within the decoherence time. Computation of the fidelity of the operations and application to the complete solution of a minimal quantum computing algorithm demonstrate in theory the feasibility of quantum control.

  5. 77 FR 67171 - Comprehensive Review of Licensing and Operating Rules for Satellite Services

    Science.gov (United States)

    2012-11-08

    ... amplifier output power, and net losses between amplifier output and antenna input. We also propose to adopt... beginning and end of life, estimated space station ] operational lifetime, reliability of the space station... operational lifetime. We propose to delete the other requirements because they are either collected elsewhere...

  6. Industry leading satellite based GNSS (Global Navigation Satellite System) positioning and monitoring solutions with real-time CORS (Continuously Operating Reference Station) networks

    Science.gov (United States)

    Janousek, Martin

    2010-05-01

    Real-Time CORS (Continuously Operating Reference Station Networks) today are typically GNSS networks for positioning and monitoring purposes. Real-Time networks can consist of a few stations for a local network up to nation- or continental wide networks with several hundred CORS stations. Such networks use wide area modeling of GNSS error sources including ionospheric, tropospheric and satellite orbit correction parameters to produce highest precision and efficiency method of positioning using GNSS. In 1998 Trimble Navigation Ltd. introduced a method of surveying with a non-physical or computed base station, called VRS (Virtual Reference Station). It is the most widely supported method of producing a network solution for precise carrier phase positioning in the industry. Surveying historically required one base as the fixed point of reference, and one or multiple rovers using that point of reference to compute their location by processing a vector result, either in real-time or in a postprocessed sense. Real-time survey is often referred to as RTK, short for real-time kinematic, and as the name suggests the results are in real time and you can move. The power of VRS is in the ability to compute a real-time wide-area solution to the factors that cause single base methods to degrade with distance. Namely, ionospheric and tropospheric modeling, and satellite orbit corrections. This is achieved by the reference network of CORS. A wide scattering of CORS across a state, typically 50-70km in mid-latitudes, creates a ground based sampling which significantly reduces the distance dependent errors that accumulate in the single base-rover relationship described early. Furthermore, GNSS networks can be used for real-time monitoring purposes at various distance range. Trimble Integrity Manager software provides a suite of motion engines designed to detect and quantify any movement in a range of scales from slow, creeping movement like subsidence, through sudden events such as

  7. 21 CFR 111.110 - What quality control operations are required for laboratory operations associated with the...

    Science.gov (United States)

    2010-04-01

    ... laboratory operations associated with the production and process control system? 111.110 Section 111.110 Food... OPERATIONS FOR DIETARY SUPPLEMENTS Production and Process Control System: Requirements for Quality Control... production and process control system? Quality control operations for laboratory operations associated...

  8. High Accuracy Attitude Control System Design for Satellite with Flexible Appendages

    Directory of Open Access Journals (Sweden)

    Wenya Zhou

    2014-01-01

    Full Text Available In order to realize the high accuracy attitude control of satellite with flexible appendages, attitude control system consisting of the controller and structural filter was designed. When the low order vibration frequency of flexible appendages is approximating the bandwidth of attitude control system, the vibration signal will enter the control system through measurement device to bring impact on the accuracy or even the stability. In order to reduce the impact of vibration of appendages on the attitude control system, the structural filter is designed in terms of rejecting the vibration of flexible appendages. Considering the potential problem of in-orbit frequency variation of the flexible appendages, the design method for the adaptive notch filter is proposed based on the in-orbit identification technology. Finally, the simulation results are given to demonstrate the feasibility and effectiveness of the proposed design techniques.

  9. South African Weather Service operational satellite based precipitation estimation technique: applications and improvements

    Directory of Open Access Journals (Sweden)

    E. de Coning

    2010-11-01

    Full Text Available Extreme weather related to heavy or more frequent precipitation events seem to be a likely possibility for the future of our planet. While precipitation measurements can be done by means of rain gauges, the obvious disadvantages of point measurements are driving meteorologists towards remotely sensed precipitation methods. In South Africa more sophisticated and expensive nowcasting technology such as radar and lightning networks are available, supported by a fairly dense rain gauge network of about 1500 gauges. In the rest of southern Africa rainfall measurements are more difficult to obtain. The availability of the local version of the Unified Model and the Meteosat Second Generation satellite data make these products ideal components of precipitation measurement in data sparse regions such as Africa. In this article the local version of the Hydroestimator (originally from NOAA/NESDIS is discussed as well as its applications for precipitation measurement in this region. Hourly accumulations of the Hydroestimator are currently used as a satellite based precipitation estimator for the South African Flash Flood Guidance system. However, the Hydroestimator is by no means a perfect representation of the real rainfall. In this study the Hydroestimator and the stratiform rainfall field from the Unified Model are both bias corrected and then combined into a new precipitation field which can feed into the South African Flash Flood Guidance system. This new product should provide a more accurate and comprehensive input to the Flash Flood Guidance systems in South Africa as well as southern Africa. In this way the southern African region where data is sparse and very few radars are available can have access to more accurate flash flood guidance.

  10. Bacterial control through contamination control in operating theatres

    NARCIS (Netherlands)

    Luscuere, P.G.

    1996-01-01

    Nowadays Operating Theatres (OT's) are well established for normai surgical use in modernised world. The application of downflow systems is some 20 years old and besides incremental improvements the concept is stil) the same as from the start. The two most common concepts are based on filtered air

  11. Controllability Analysis for Operation Margin of Zone 3 Impedance Relay

    Science.gov (United States)

    Li, Shenghu; Yorino, Naoto; Zoka, Yoshifumi

    Undesirable operation of zone 3 impedance relay (mho relays) is a possible factor for causing cascading failure as seen in several previous large scale blackouts, where power flow redistribution and power swing caused by outage or switching operations satisfy the condition for the relay operation. So far, the condition itself has not fully been investigated, and therefore, there has been little attempt to avoid the relay operation by means of direct power flow control. This paper analyzes the condition for zone 3 relay operation from the viewpoint of its sensitivity to power flow. An operating margin for security is defined for each relay to carry out effective monitoring. It is newly pointed out that undesirable operation can be effectively avoided by reactive power controls as well as real power controls. The method to compute the operation margin is also given through the analysis of the optimal Var location to control the operation margin. Effectiveness of the proposed method is demonstrated using the IEEE test systems.

  12. Real-time horizontality adjusting and control system of a large platform applied to satellite experiment

    Institute of Scientific and Technical Information of China (English)

    ZHONG Shi-sheng; ZHANG Shi-peng; WANG Rui

    2007-01-01

    In order to satisfy a satellite horizontality requirement in an experiment, it is indispensable to monitor and adjust the horizontality of a large platform loading the satellite under the condition of ultra-low temperature with real time. So the control system design and control strategy are described in detail to accomplish the horizontality monitoring and adjusting. The system adopts the industry control computer as the upper computer and the SIEMENS S7-300 PLC as the lower computer. The upper computer that bases on industry configuration software IFIX takes charge of monitoring the platform and puts forward the control strategy. PLC takes charge of receiving the adjusting instructions and controlling the legs moving to accomplish the horizontality adjusting. The horizontality adjusting strategy is emphasized and the concept of grads is introduced to establish a mathematics model of the platform inclined state, so the adjusting method is obtained. Accordingly the key question of the automatic horizontality adjusting is solved in this control system.

  13. Controlled remote implementation of partially unknown quantum operation

    Institute of Scientific and Technical Information of China (English)

    FAN QiuBo; LIU DongDong

    2008-01-01

    A protocol for controlled remote implementation of a partially unknown operation on an arbitrary quantum state is proposed. In this protocol, a task can be performed using a GHZ state shared among three distant parties: Alice, Bob and the controller Charlie. This protocol is also generalized to the multi-party control system based on sharing an N-qubit GHZ state.

  14. Eigensensitivity in integrated design. [of earth-pointing satellite's control system

    Science.gov (United States)

    Kenny, Sean P.; Hou, Gene J.; Belvin, W. K.

    1990-01-01

    An application of eigensensitivity analysis to the control-structure integrated design process is presented with an emphasis placed on computational efficiency improvement of the overall design optimization process. The computational efficiency of eigenvalue/vector sensitivity analysis is demonstrated using the Earth Pointing Satellite in the context of a control-structure integrated design program. Results for a 2 percent design variable perturbation with and without the effects of the actuator mass show a 42 and 52 percent reduction in CPU time, respectively.

  15. Synchronization and Antisynchronization of a Planar Oscillation of Satellite in an Elliptic Orbit via Active Control

    Directory of Open Access Journals (Sweden)

    Mohammad Shahzad

    2011-01-01

    Full Text Available We have investigated the synchronization and antisynchronization behaviour of two identical planar oscillation of a satellite in elliptic orbit evolving from different initial conditions using the active control technique based on the Lyapunov stability theory and the Routh-Hurwitz criteria. The designed controller, with our own choice of the coefficient matrix of the error dynamics that satisfy the Lyapunov stability theory and the Routh-Hurwitz criteria, is found to be effective in the stabilization of the error states at the origin, thereby, achieving synchronization and antisynchronization between the states variables of two nonlinear dynamical systems under consideration. The results are validated by numerical simulations using mathematica.

  16. Antenna pointing system for satellite tracking based on Kalman filtering and model predictive control techniques

    Science.gov (United States)

    Souza, André L. G.; Ishihara, João Y.; Ferreira, Henrique C.; Borges, Renato A.; Borges, Geovany A.

    2016-12-01

    The present work proposes a new approach for an antenna pointing system for satellite tracking. Such a system uses the received signal to estimate the beam pointing deviation and then adjusts the antenna pointing. The present work has two contributions. First, the estimation is performed by a Kalman filter based conical scan technique. This technique uses the Kalman filter avoiding the batch estimator and applies a mathematical manipulation avoiding the linearization approximations. Secondly, a control technique based on the model predictive control together with an explicit state feedback solution are obtained in order to reduce the computational burden. Numerical examples illustrate the results.

  17. An Automated Tool to Enable the Distributed Operations of Air Force Satellites

    Science.gov (United States)

    2002-01-01

    commanding and telemetry commanding. It is implemented on Gensym ’ s G2 expert system. • The System 500 Model550 front-end processor from L-3...results led to the concept of a virtual distributed operations environment, in which cross- trained staff are dynamically allocated to missions, as needed...tasks are the same (e.g., planning, fault detection). However, there are some key differences between operations, such as: • Near-real time

  18. CONTROL OF OPERATIONAL HYGIENE IN FAST FOOD RESTAURANTS

    Directory of Open Access Journals (Sweden)

    Ľubomír Lopašovský

    2014-02-01

    Full Text Available The aim of this study was control of operational hygiene in fast-food restaurants. Control was carried out in three fast food restaurants. Samples were collected from ten sampling places, in cycles of morning, afternoon and evening. Sanitation process was also controlled in each operation. Grown colonies of microorganisms were counted after incubation in a thermostat. Samples were collected using a 3M ® plates PetrifilmTM - modern detection methods. Presence of coliform bacteria was determined by this method. In the first operation 1 sample from 30 sampling places did not meet the prescribed value according to standard. In the second operation 5 samples from 30 sampling places did not meet prescribed value according to the standard. In the third operation 2 samples from 30 sampling places did not meet the prescribed values.

  19. Graph-tree-based software control flow checking for COTS processors on pico-satellites

    Institute of Scientific and Technical Information of China (English)

    Yang Mu; Wang Hao; Zheng Yangming; Jin Zhonghe

    2013-01-01

    This paper proposes a generic high-performance and low-time-overhead software control flow checking solution,graph-tree-based control flow checking (GTCFC) for space-borne commercial-off-the-shelf (COTS) processors.A graph tree data structure with a topology similar to common trees is introduced to transform the control flow graphs of target programs.This together with design of IDs and signatures of its vertices and edges allows for an easy check of legality of actual branching during target program execution.As a result,the algorithm not only is capable of detecting all single and multiple branching errors with low latency and time overheads along with a linear-complexity space overhead,but also remains generic among arbitrary instruction sets and independent of any specific hardware.Tests of the algorithm using a COTS-processor-based on-board computer (OBC) of in-service ZDPS-1A pico-satellite products show that GTCFC can detect over 90% of the randomly injected and all-pattern-covering branching errors for different types of target programs,with performance and overheads consistent with the theoretical analysis; and beats well-established preeminent control flow checking algorithms in these dimensions.Furthermore,it is validated that GTCGC not only can be accommodated in pico-satellites conveniently with still sufficient system margins left,but also has the ability to minimize the risk of control flow errors being undetected in their space missions.Therefore,due to its effectiveness,efficiency,and compatibility,the GTCFC solution is ready for applications on COTS processors on pico-satellites in their real space missions.

  20. Robust optimal sun-pointing control of a large solar power satellite

    Science.gov (United States)

    Wu, Shunan; Zhang, Kaiming; Peng, Haijun; Wu, Zhigang; Radice, Gianmarco

    2016-10-01

    The robust optimal sun-pointing control strategy for a large geostationary solar power satellite (SPS) is addressed in this paper. The SPS is considered as a huge rigid body, and the sun-pointing dynamics are firstly proposed in the state space representation. The perturbation effects caused by gravity gradient, solar radiation pressure and microwave reaction are investigated. To perform sun-pointing maneuvers, a periodically time-varying robust optimal LQR controller is designed to assess the pointing accuracy and the control inputs. It should be noted that, to reduce the pointing errors, the disturbance rejection technique is combined into the proposed LQR controller. A recursive algorithm is then proposed to solve the optimal LQR control gain. Simulation results are finally provided to illustrate the performance of the proposed closed-loop system.

  1. Tractor controls actuating force limits for Indian operators.

    Science.gov (United States)

    Mehta, C R; Pandey, M M; Tiwari, P S; Gite, L P; Khadatkar, Abhijit

    2011-01-01

    In four-wheel tractors, proper design of controls is important for comfortable and safe operation of the tractor. The design involves location and dimensions of controls as well as strength limits for operating these controls. The present study was aimed to quantify human strength for operation of tractor controls and to recommend the maximum control actuating forces for normal operation of tractors based on strength capability of 3,423 Indian male agricultural workers. The 5th percentile values of strength parameters i.e. leg strength sitting (left and right), foot strength sitting (right), torque strength (both hands) sitting, push strength (left hand and right hand) sitting and pull strength (left hand and right hand) sitting of agricultural workers collected using a strength measurement set-up were taken into consideration for the study. It was recommended that the maximum actuating forces for normal operation of frequently operated brake and clutch pedals of tractors should not exceed 260 N and 125 N based on 5th percentile values of right and left leg strength of male agricultural workers, respectively. The maximum actuating force required in steering wheel operation should not exceed 51 N based on 5th percentile value of torque strength (both hands) sitting of workers. The maximum actuating forces required for operating frequently operated levers viz. gear selection, speed selection, hydraulic control and hand throttle of Indian tractors should not exceed 46 N, 46 N, 25 N and 25 N, respectively. It may be concluded that the maximum actuating force limits as given in Bureau of Indian Standards IS 10703 are very high as compared to the findings of the study based on strength data of Indian male operators, which highlight the need to revise the standard.

  2. Remotely operated gripper provides vertical control rod movement

    Science.gov (United States)

    Hutter, E.; Koch, L. J.

    1968-01-01

    Remote actuation of a gripper shaft affects vertical engagement between a drive shaft and control rod. A secondary function of the gripper is to provide remote indication of positive completion of the gripping or ungripping operation.

  3. Distributed Command/Control Impacts on NAS Operations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Command and Control (C2) activities abound in the NAS, and significantly influence daily operations and overall NAS efficiency. Since C2 effects are so prominent,...

  4. Challenges for process system engineering in infrastructure operation and control

    NARCIS (Netherlands)

    Lukszo, Z.; Weijnen, M.P.C.; Negenborn, R.R.; De Schutter, B.; Ilic, M.

    2006-01-01

    The need for improving the operation and control of infrastructure systems has created a demand on optimization methods applicable in the area of complex sociotechnical systems operated by a multitude of actors in a setting of decentralized decision making. This paper briefly presents main classes o

  5. The character of harms: operational challenges in control

    National Research Council Canada - National Science Library

    Sparrow, Malcolm K

    2008-01-01

    ... - an operational approach which he terms "the sabotage of harms." The book explores the institutional arrangements and decision-frameworks necessary to support this emerging operational model. Written for reflective practitioners charged with risk-control responsibilities across the public, private, and non-governmental sectors, The Character ...

  6. Evaluation of the Operational Stress Control and Readiness (OSCAR) Program

    Science.gov (United States)

    2015-01-01

    that their unit cares about them, and that everyone gets treated fairly and equally. Whether it’s PTS [posttraumatic stress ] or financial issues. When...training on suicide prevention (U.S. Marine Corps, 2012). Recommendation 2.2. Integrate Combat and Operational Stress –Control Training into the...Christine Anne Vaughan, Carrie M. Farmer, Joshua Breslau, Crystal Burnette Evaluation of the Operational Stress Control and Readiness (OSCAR

  7. Controlled English for Effective Communication during Coalition Operations

    Science.gov (United States)

    2013-06-01

    simplified and common form of expression in English , which is not only user- friendly in nature but is also restricted in vocabulary and grammar for clear...18th ICCRTS C2 in Underdeveloped, Degraded and Denied Operational Environments Title of Paper: Controlled English for Effective Communication...4. TITLE AND SUBTITLE Controlled English for Effective Communication during Coalition Operations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  8. A new, long-term daily satellite-based rainfall dataset for operational monitoring in Africa

    Science.gov (United States)

    Maidment, Ross I.; Grimes, David; Black, Emily; Tarnavsky, Elena; Young, Matthew; Greatrex, Helen; Allan, Richard P.; Stein, Thorwald; Nkonde, Edson; Senkunda, Samuel; Alcántara, Edgar Misael Uribe

    2017-05-01

    Rainfall information is essential for many applications in developing countries, and yet, continually updated information at fine temporal and spatial scales is lacking. In Africa, rainfall monitoring is particularly important given the close relationship between climate and livelihoods. To address this information gap, this paper describes two versions (v2.0 and v3.0) of the TAMSAT daily rainfall dataset based on high-resolution thermal-infrared observations, available from 1983 to the present. The datasets are based on the disaggregation of 10-day (v2.0) and 5-day (v3.0) total TAMSAT rainfall estimates to a daily time-step using daily cold cloud duration. This approach provides temporally consistent historic and near-real time daily rainfall information for all of Africa. The estimates have been evaluated using ground-based observations from five countries with contrasting rainfall climates (Mozambique, Niger, Nigeria, Uganda, and Zambia) and compared to other satellite-based rainfall estimates. The results indicate that both versions of the TAMSAT daily estimates reliably detects rainy days, but have less skill in capturing rainfall amount—results that are comparable to the other datasets.

  9. Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program.

    Science.gov (United States)

    Lee, Eun Ju; Jan, Arif Tasleem; Baig, Mohammad Hassan; Ashraf, Jalaluddin Mohammad; Nahm, Sang-Soep; Kim, Yong-Woon; Park, So-Young; Choi, Inho

    2016-08-01

    Differentiation of muscle satellite cells (MSCs) involves interaction of the proteins present in the extracellular matrix (ECM) with MSCs to regulate their activity, and therefore phenotype. Herein, we report fibromodulin (FMOD), a member of the proteoglycan family participating in the assembly of ECM, as a novel regulator of myostatin (MSTN) during myoblast differentiation. In addition to having a pronounced effect on the expression of myogenic marker genes [myogenin (MYOG) and myosin light chain 2 (MYL2)], FMOD was found to maintain the transcriptional activity of MSTN Moreover, coimmunoprecipitation and in silico studies performed to investigate the interaction of FMOD helped confirm that it antagonizes MSTN function by distorting its folding and preventing its binding to activin receptor type IIB. Furthermore, in vivo studies revealed that FMOD plays an active role in healing by increasing satellite cell recruitment to sites of injury. Together, these findings disclose a hitherto unrecognized regulatory role for FMOD in MSCs and highlight new mechanisms whereby FMOD circumvents the inhibitory effects of MSTN and triggers myoblast differentiation. These findings offer a basis for the design of novel MSTN inhibitors that promote muscle regeneration after injury or for the development of pharmaceutical agents for the treatment of different muscle atrophies.-Lee, E. J., Jan, A. T., Baig, M. H., Ashraf, J. M., Nahm, S.-S., Kim, Y.-W., Park, S.-Y., Choi, I. Fibromodulin: a master regulator of myostatin controlling progression of satellite cells through a myogenic program.

  10. A distributed model predictive control (MPC) fault reconfiguration strategy for formation flying satellites

    Science.gov (United States)

    Esfahani, N. R.; Khorasani, K.

    2016-05-01

    In this paper, an active distributed (also referred to as semi-decentralised) fault recovery control scheme is proposed that employs inaccurate and unreliable fault information into a model-predictive-control-based design. The objective is to compensate for the identified actuator faults that are subject to uncertainties and detection time delays, in the attitude control subsystems of formation flying satellites. The proposed distributed fault recovery scheme is developed through a two-level hierarchical framework. In the first level, or the agent level, the fault is recovered locally to maintain as much as possible the design specifications, feasibility, and tracking performance of all the agents. In the second level, or the formation level, the recovery is carried out by enhancing the entire team performance. The fault recovery performance of our proposed distributed (semi-decentralised) scheme is compared with two other alternative schemes, namely the centralised and the decentralised fault recovery schemes. It is shown that the distributed (semi-decentralised) fault recovery scheme satisfies the recovery design specifications and also imposes lower fault compensation control effort cost and communication bandwidth requirements as compared to the centralised scheme. Our proposed distributed (semi-decentralised) scheme also outperforms the achievable performance capabilities of the decentralised scheme. Simulation results corresponding to a network of four precision formation flight satellites are also provided to demonstrate and illustrate the advantages of our proposed distributed (semi-decentralised) fault recovery strategy.

  11. Adaptive sliding mode controller based on super-twist observer for tethered satellite system

    Science.gov (United States)

    Keshtkar, Sajjad; Poznyak, Alexander

    2016-09-01

    In this work, the sliding mode control based on the super-twist observer is presented. The parameters of the controller as well as the observer are admitted to be time-varying and depending on available current measurements. In view of that, the considered controller is referred to as an adaptive one. It is shown that the deviations of the generated state estimates from real state values together with a distance of the closed-loop system trajectories to a desired sliding surface reach a μ-zone around the origin in finite time. The application of the suggested controller is illustrated for the orientation of a tethered satellite system in a required position.

  12. Nonlinear dynamics of mini-satellite respinup by weak internal controllable torques

    Energy Technology Data Exchange (ETDEWEB)

    Somov, Yevgeny, E-mail: e-somov@mail.ru [Samara State Technical University, Department for Guidance, Navigation and Control, 244 Molodogvardeyskaya Str., Samara 443100 (Russian Federation)

    2014-12-10

    Contemporary space engineering advanced new problem before theoretical mechanics and motion control theory: a spacecraft directed respinup by the weak restricted control internal forces. The paper presents some results on this problem, which is very actual for energy supply of information mini-satellites (for communication, geodesy, radio- and opto-electronic observation of the Earth et al.) with electro-reaction plasma thrusters and gyro moment cluster based on the reaction wheels or the control moment gyros. The solution achieved is based on the methods for synthesis of nonlinear robust control and on rigorous analytical proof for the required spacecraft rotation stability by Lyapunov function method. These results were verified by a computer simulation of strongly nonlinear oscillatory processes at respinuping of a flexible spacecraft.

  13. Development of an integrated spacecraft Guidance, Navigation, & Control subsystem for automated proximity operations

    Science.gov (United States)

    Schulte, Peter Z.; Spencer, David A.

    2016-01-01

    This paper describes the development and validation process of a highly automated Guidance, Navigation, & Control subsystem for a small satellite on-orbit inspection application, enabling proximity operations without human-in-the-loop interaction. The paper focuses on the integration and testing of Guidance, Navigation, & Control software and the development of decision logic to address the question of how such a system can be effectively implemented for full automation. This process is unique because a multitude of operational scenarios must be considered and a set of complex interactions between subsystem algorithms must be defined to achieve the automation goal. The Prox-1 mission is currently under development within the Space Systems Design Laboratory at the Georgia Institute of Technology. The mission involves the characterization of new small satellite component technologies, deployment of the LightSail 3U CubeSat, entering into a trailing orbit relative to LightSail using ground-in-the-loop commands, and demonstration of automated proximity operations through formation flight and natural motion circumnavigation maneuvers. Operations such as these may be utilized for many scenarios including on-orbit inspection, refueling, repair, construction, reconnaissance, docking, and debris mitigation activities. Prox-1 uses onboard sensors and imaging instruments to perform Guidance, Navigation, & Control operations during on-orbit inspection of LightSail. Navigation filters perform relative orbit determination based on images of the target spacecraft, and guidance algorithms conduct automated maneuver planning. A slew and tracking controller sends attitude actuation commands to a set of control moment gyroscopes, and other controllers manage desaturation, detumble, thruster firing, and target acquisition/recovery. All Guidance, Navigation, & Control algorithms are developed in a MATLAB/Simulink six degree-of-freedom simulation environment and are integrated using

  14. CONTROL COMMAND SYSTEMS IMPACT ON THE RAILWAY OPERATIONAL SAFETY

    Directory of Open Access Journals (Sweden)

    Marek Pawlik

    2015-04-01

    Full Text Available Purpose. Safety is seen as a must, for railway transport market. However it is not so obvious what does safety exactly mean as it means different things for different experts. Showing safety ensured by control command systems as a component of the railway operational safety and pointing associated challenges especially those arising from subdivision of the national railway system into different entities. Methodology. To achieve this purpose control command and signalling systems keeping safe distances between trains, preventing setting conflicting train routs, locking of the mobile elements of the switches, protecting the level crossings, enabling safe incorporation of additional trains were analyzed. Findings. Article analyses how control command system influence operational safety taking into account safety of the control-command system itself, interfaces on one side between signalling systems and control command system and on the other side between control command system and vehicle control systems, transmission, maintenance, and operation in degraded modes of running. Originality. New and high-effective scope of tests which are necessary for putting new control command installation into service both track-side and on-board are proposed. Practical value. Control command implementations will significantly improve operational safety, however it is possible only when recommendations defined in this article are taken into account. This means that all the components including interfaces have to meet acceptable hazard rate 10E-9 and have to be properly design, constructed, assembled and maintained, all taking into account whole chain of functions performed and supervised by different railway entities.

  15. Controlling laser beam irradiation area using an optical duplicate system to improve satellite-ground laser communications

    Science.gov (United States)

    Nakayama, Tomoko; Takayama, Yoshihisa; Fujikawa, Chiemi; Kodate, Kashiko

    2016-08-01

    To improve the quality of ground to satellite laser communications, we propose an optical duplicate system of the optical ground station. Our proposed approach can be used to control the beam irradiation area for a satellite position without changing the total power of the output beam and the mechanical drive unit; this is performed by controlling the input pattern of a liquid crystal filter inserted in the input plane of the optical duplicate system. Most of the power of the diffracted laser beam emitted from the ground is focused on the optical axis. By distributing the power to side lobes, it is possible to extend the coverage area for a satellite position. This system allows the laser beam irradiation area to be controlled by a sufficient degree by adjusting the threshold of the satellite reception level. We verify the efficacy of the system using wave optics numerical calculations.

  16. Post-operative pain control after tonsillectomy: dexametasone vs tramadol.

    Science.gov (United States)

    Topal, Kubra; Aktan, Bulent; Sakat, Muhammed Sedat; Kilic, Korhan; Gozeler, Mustafa Sitki

    2017-06-01

    Tramadol was found to be more effective than dexamethasone in post-operative pain control, with long-lasting relief of pain. This study aimed to compare the effects of pre-operative local injections of tramadol and dexamethasone on post-operative pain, nausea and vomiting in patients who underwent tonsillectomy. Sixty patients between 3-13 years of age who were planned for tonsillectomy were included in the study. Patients were divided into three groups. Group 1 was the control group. Patients in Group 2 received 0.3 mg/kg Dexamethasone and Group 3 received 0.1 mg/kg Tramadol injection to the peritonsillary space just before the operation. Patients were evaluated for nausea, vomiting, and pain. When the control and the dexamethasone groups were compared; there were statistically significant differences in pain scores at post-operative 15 and 30 min, whereas there was no statistically significant difference in pain scores at other hours. When the control and tramadol groups were compared, there was a statistically significant difference in pain scores at all intervals. When tramadol and dexamethasone groups were compared, there was no statistically significant difference in pain scores at post-operative 15 and 30 min, 1 and 2 h, whereas there was a statistically significant difference in pain scores at post-operative 6 and 24 h.

  17. Intelligent Real-Time Reservoir Operation for Flood Control

    Science.gov (United States)

    Chang, L.; Hsu, H.

    2008-12-01

    Real-time flood control of a multi-purpose reservoir should consider decreasing the flood peak stage downstream and storing floodwaters for future usage during typhoon seasons. It is a continuous and instant decision-making process based on relevant operating rules, policy and water laws, in addition the immediate rainfall and the hydrology information; however, it is difficult to learn the intelligent experience from the elder operators. The main purpose of this study is to establish the automatic reservoir flood control model to achieve the goal of a reservoir operation during flood periods. In this study, we propose an intelligent reservoir operating methodology for real-time flood control. First, the genetic algorithm is used to search the optimal solutions, which can be considered as extracting the knowledge of reservoir operation strategies. Then, the adaptive network-based fuzzy inference system (ANFIS), which uses a hybrid learning procedure for extracting knowledge in the form of fuzzy if-then rules, is used to learn the input-output patterns and then to estimate the optimal flood operation. The Shihmen reservoir in Northern Taiwan was used as a case study, where its 26 typhoon events are investigated by the proposed method. The results demonstrate that the proposed control model can perform much better than the original reservoir operator in 26 flood events and effectively achieve decreasing peak flood stage downstream and storing floodwaters for future usage.

  18. Ground controlled robotic assembly operations for Space Station Freedom

    Science.gov (United States)

    Parrish, Joseph C.

    1991-01-01

    A number of dextrous robotic systems and associated positioning and transportation devices are available on Space Station Freedom (SSF) to perform assembly tasks that would otherwise need to be performed by extravehicular activity (EVA) crewmembers. The currently planned operating mode for these robotic systems during the assembly phase is teleoperation by intravehicular activity (IVA) crewmembers. While this operating mode is less hazardous and expensive than manned EVA operations, and has insignificant control loop time delays, the amount of IVA time available to support telerobotic operations is much less than the anticipated requirements. Some alternative is needed to allow the robotic systems to perform useful tasks without exhausting the available IVA resources; ground control is one such alternative. The issues associated with ground control of SSF robotic systems to alleviate onboard crew time availability constraints are investigated. Key technical issues include the effect of communication time delays, the need for safe, reliable execution of remote operations, and required modifications to the SSF ground and flight system architecture. Time delay compensation techniques such as predictive displays and world model-based force reflection are addressed and collision detection and avoidance strategies to ensure the safety of the on-orbit crew, Orbiter, and SSF are described. Although more time consuming and difficult than IVA controlled teleoperations or manned EVA, ground controlled telerobotic operations offer significant benefits during the SSF assembly phase, and should be considered in assembly planning activities.

  19. Command Generation and Control of Momentum Exchange Electrodynamic Reboost Tethered Satellite

    Science.gov (United States)

    Robertson, Michael J.

    2005-01-01

    The research completed for this NASA Graduate Student Research Program Fellowship sought to enhance the current state-of-the-art dynamic models and control laws for Momentum Exchange Electrodynamic Reboost satellite systems by utilizing command generation, specifically Input Shaping. The precise control of tethered spacecraft with flexible appendages is extremely difficult. The complexity is magnified many times when the satellite must interact with other satellites as in a momentum exchange via a tether. The Momentum Exchange Electronic Reboost Tether (MXER) concept encapsulates all of these challenging tasks [l]. Input Shaping is a command generation technique that allows flexible spacecraft to move without inducing residual vibration [2], limit transient deflection [3] and utilize fuel-efficient actuation [4]. Input shaping is implemented by convolving a sequence of impulses, known as the input shaper, with a desired system command to produce a shaped input that is then used to drive the system. This process is demonstrated in Figure 1. The shaped command is then use to drive the system without residual vibration while meeting many other performance specifications. The completed work developed tether control algorithms for retrieval. A simple model of the tether response has been developed and command shaping was implemented to minimize unwanted dynamics. A model of a flexible electrodynamic tether has been developed to investigate the tether s response during reboost. Command shaping techniques have been developed to eliminate the tether oscillations and reduce the tether s deflection to pre-specified levels during reboost. Additionally, a model for the spin-up of a tethered system was developed. This model was used in determining the parameters for optimization the resulting angular velocity.

  20. The Geostationary Lightning Mapper (GLM) for the GOES-R Series Next Generation Operational Environmental Satellite Constellation

    Science.gov (United States)

    Goodman, Steven J.; Blakeslee, Richard; Koshak, William; Petersen, Walter; Carey, Larry; Mach, Douglas; Buechler, Dennis; Bateman, Monte; McCaul, Eugene; Bruning, Eric; Albrecht, Rachel; MacGorman, Donald

    2010-01-01

    The next generation Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2015 is a follow on to the existing GOES system currently operating over the Western Hemisphere. The system will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. The system provides products including lightning, cloud properties, rainfall rate, volcanic ash, air quality, hurricane intensity, and fire/hot spot characterization. Advancements over current GOES include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved spectral, spatial, and temporal resolution for the 16-channel Advanced Baseline Imager (ABI). The Geostationary Lightning Mapper (GLM), an optical transient detector will map total (in-cloud and cloud-to-ground) lightning flashes continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions, from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fully operational. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the higher level algorithms and applications using the GLM alone and decision aids incorporating information from the ABI, ground-based weather radar, and numerical models. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional lightning networks are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time total lightning mapping data are also being provided in an experimental mode to selected National Weather Service (NWS) national centers and forecast offices via

  1. Flight results from the gravity-gradient-controlled RAE-1 satellite

    Science.gov (United States)

    Blanchard, D. L.

    1986-01-01

    The in-orbit dynamics of a large, flexible spacecraft has been modeled with a computer simulation, which was used for designing the control system, developing a deployment and gravity-gradient capture procedure, predicting the steady-state behavior, and designing a series of dynamics experiments for the Radio Astronomy Explorer (RAE) satellite. This flexible body dynamics simulator permits three-dimensional, large-angle rotation of the total spacecraft and includes effects of orbit eccentricity, thermal bending, solar pressure, gravitational accelerations, and the damper system. Flight results are consistent with the simulator predictions and are presented for the deployment and capture phases, the steady-state mission, and the dynamics experiments.

  2. Monolithic sensors for low frequency motion measurement and control of spacecrafts and satellites

    Science.gov (United States)

    Barone, F.; Giordano, G.; Acernese, F.; Romano, R.

    2016-10-01

    In this paper we describe the characteristics and performances of a monolithic sensor designed for low frequency motion measurement and control of spacecrafts and satellites, whose mechanics is based on the UNISA Folded Pendulum. The latter, developed for ground-based applications, exhibits unique features (compactness, lightness, scalability, low resonance frequency and high quality factor), consequence of the action of the gravitational force on its inertial mass. In this paper we introduce and discuss the general methodology used to extend the application of ground-based folded pendulums to space, also in total absence of gravity, still keeping all their peculiar features and characteristics.

  3. Analysis of Access Control Policies in Operating Systems

    Science.gov (United States)

    Chen, Hong

    2009-01-01

    Operating systems rely heavily on access control mechanisms to achieve security goals and defend against remote and local attacks. The complexities of modern access control mechanisms and the scale of policy configurations are often overwhelming to system administrators and software developers. Therefore, mis-configurations are common, and the…

  4. Analysis of Access Control Policies in Operating Systems

    Science.gov (United States)

    Chen, Hong

    2009-01-01

    Operating systems rely heavily on access control mechanisms to achieve security goals and defend against remote and local attacks. The complexities of modern access control mechanisms and the scale of policy configurations are often overwhelming to system administrators and software developers. Therefore, mis-configurations are common, and the…

  5. A Topology Control Strategy with Reliability Assurance for Satellite Cluster Networks in Earth Observation

    Science.gov (United States)

    Chen, Qing; Zhang, Jinxiu; Hu, Ze

    2017-01-01

    This article investigates the dynamic topology control problem of satellite cluster networks (SCNs) in Earth observation (EO) missions by applying a novel metric of stability for inter-satellite links (ISLs). The properties of the periodicity and predictability of satellites’ relative position are involved in the link cost metric which is to give a selection criterion for choosing the most reliable data routing paths. Also, a cooperative work model with reliability is proposed for the situation of emergency EO missions. Based on the link cost metric and the proposed reliability model, a reliability assurance topology control algorithm and its corresponding dynamic topology control (RAT) strategy are established to maximize the stability of data transmission in the SCNs. The SCNs scenario is tested through some numeric simulations of the topology stability of average topology lifetime and average packet loss rate. Simulation results show that the proposed reliable strategy applied in SCNs significantly improves the data transmission performance and prolongs the average topology lifetime. PMID:28241474

  6. Viability of Hybrid Systems A Controllability Operator Approach

    CERN Document Server

    Labinaz, G

    2012-01-01

    The problem of viability of hybrid systems is considered in this work. A model for a hybrid system is developed including a means of including three forms of uncertainty: transition dynamics, structural uncertainty, and parametric uncertainty. A computational basis for viability of hybrid systems is developed and applied to three control law classes. An approach is developed for robust viability based on two extensions of the controllability operator. The three-tank example is examined for both the viability problem and robust viability problem. The theory is applied through simulation to an active magnetic bearing system and to a batch polymerization process showing that viability can be satisfied in practice. The problem of viable attainability is examined based on the controllability operator approach introduced by Nerode and colleagues. Lastly, properties of the controllability operator are presented.

  7. Multi-mission Satellite Management

    Science.gov (United States)

    Jamilkowski, M. L.; Teter, M. A.; Grant, K. D.; Dougherty, B.; Cochran, S.

    2015-12-01

    NOAA's next-generation environmental satellite, the Joint Polar Satellite System (JPSS) replaces the current Polar-orbiting Operational Environmental Satellites (POES). JPSS satellites carry sensors which collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The first JPSS satellite was launched in 2011 and is currently NOAA's primary operational polar satellite. The JPSS ground system is the Common Ground System (CGS), and provides command, control, and communications (C3) and data processing (DP). A multi-mission system, CGS provides combinations of C3/DP for numerous NASA, NOAA, DoD, and international missions. In preparation for the next JPSS satellite, CGS improved its multi-mission capabilities to enhance mission operations for larger constellations of earth observing satellites with the added benefit of streamlining mission operations for other NOAA missions. CGS's multi-mission capabilities allows management all of assets as a single enterprise, more efficiently using ground resources and personnel and consolidating multiple ground systems into one. Sophisticated scheduling algorithms compare mission priorities and constraints across all ground stations, creating an enterprise schedule optimized to mission needs, which CGS executes to acquire the satellite link, uplink commands, downlink and route data to the operations and data processing facilities, and generate the final products for delivery to downstream users. This paper will illustrate the CGS's ability to manage multiple, enterprise-wide polar orbiting missions by demonstrating resource modeling and tasking, production of enterprise contact schedules for NOAA's Fairbanks ground station (using both standing and ad hoc requests), deconflicting resources due to ground outages, and updating resource allocations through dynamic priority definitions.

  8. ADVANCED COMPRESSOR ENGINE CONTROLS TO ENHANCE OPERATION, RELIABILITY AND INTEGRITY

    Energy Technology Data Exchange (ETDEWEB)

    Gary D. Bourn; Jess W. Gingrich; Jack A. Smith

    2004-03-01

    This document is the final report for the ''Advanced Compressor Engine Controls to Enhance Operation, Reliability, and Integrity'' project. SwRI conducted this project for DOE in conjunction with Cooper Compression, under DOE contract number DE-FC26-03NT41859. This report addresses an investigation of engine controls for integral compressor engines and the development of control strategies that implement closed-loop NOX emissions feedback.

  9. Adaptive Hierarchical Sliding Mode Control with Input Saturation for Attitude Regulation of Multi-satellite Tethered System

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2017-06-01

    This paper proposes a novel adaptive hierarchical sliding mode control for the attitude regulation of the multi-satellite inline tethered system, where the input saturation is taken into account. The governing equations for the attitude dynamics of the three-satellite inline tethered system are derived firstly by utilizing Lagrangian mechanics theory. Considering the fact that the attitude of the central satellite can be adjusted by using the simple exponential stabilization scheme, the decoupling of the central satellite and the terminal ones is presented, and in addition, the new adaptive sliding mode control law is applied to stabilize the attitude dynamics of the two terminal satellites based on the synchronization and partial contraction theory. In the adaptive hierarchical sliding mode control design, the input is modeled as saturated input due to the fact that the flywheel torque is bounded, and meanwhile, an adaptive update rate is introduced to eliminate the effect of the saturated input and the external perturbation. The proposed control scheme can be applied on the two-satellite system to achieve fixed-point rotation. Numerical results validate the effectiveness of the proposed method.

  10. Adaptive Hierarchical Sliding Mode Control with Input Saturation for Attitude Regulation of Multi-satellite Tethered System

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2016-11-01

    This paper proposes a novel adaptive hierarchical sliding mode control for the attitude regulation of the multi-satellite inline tethered system, where the input saturation is taken into account. The governing equations for the attitude dynamics of the three-satellite inline tethered system are derived firstly by utilizing Lagrangian mechanics theory. Considering the fact that the attitude of the central satellite can be adjusted by using the simple exponential stabilization scheme, the decoupling of the central satellite and the terminal ones is presented, and in addition, the new adaptive sliding mode control law is applied to stabilize the attitude dynamics of the two terminal satellites based on the synchronization and partial contraction theory. In the adaptive hierarchical sliding mode control design, the input is modeled as saturated input due to the fact that the flywheel torque is bounded, and meanwhile, an adaptive update rate is introduced to eliminate the effect of the saturated input and the external perturbation. The proposed control scheme can be applied on the two-satellite system to achieve fixed-point rotation. Numerical results validate the effectiveness of the proposed method.

  11. Operational High Resolution Land Cover Map Production at the Country Scale Using Satellite Image Time Series

    Directory of Open Access Journals (Sweden)

    Jordi Inglada

    2017-01-01

    Full Text Available A detailed and accurate knowledge of land cover is crucial for many scientific and operational applications, and as such, it has been identified as an Essential Climate Variable. This accurate knowledge needs frequent updates. This paper presents a methodology for the fully automatic production of land cover maps at country scale using high resolution optical image time series which is based on supervised classification and uses existing databases as reference data for training and validation. The originality of the approach resides in the use of all available image data, a simple pre-processing step leading to a homogeneous set of acquisition dates over the whole area and the use of a supervised classifier which is robust to errors in the reference data. The produced maps have a kappa coefficient of 0.86 with 17 land cover classes. The processing is efficient, allowing a fast delivery of the maps after the acquisition of the image data, does not need expensive field surveys for model calibration and validation, nor human operators for decision making, and uses open and freely available imagery. The land cover maps are provided with a confidence map which gives information at the pixel level about the expected quality of the result.

  12. Development of control system in abdominal operating ROV

    Directory of Open Access Journals (Sweden)

    ZHANG Weikang

    2017-03-01

    Full Text Available In order to satisfy all the requirements of Unmanned Underwater Vehicle(UUVrecovery tasks, a new type of abdominal operating Remote Operated Vehicle(ROV was developed. The abdominal operating ROV is different from the general ROV which works by a manipulator, as it completes the docking and recovery tasks of UUVs with its abdominal operating mechanism. In this paper, the system composition and principles of the abdominal operating ROV are presented. We then propose a framework for a control system in which the integrated industrial reinforced computer acts as a surface monitor unit, while the PC104 embedded industrial computer acts as the underwater master control unit and the other drive boards act as the driver unit. In addition, the dynamics model and a robust H-infinity controller for automatic orientation in the horizontal plane were designed and built. Single tests, system tests and underwater tests show that this control system has good real-time performance and reliability, and it can complete the recovery task of a UUV. The presented structure and algorithm could have reference significance to the control system development of mobile robots, drones, and biomimetic robot.

  13. SMES application for frequency control during islanded microgrid operation

    Science.gov (United States)

    Kim, A.-Rong; Kim, Gyeong-Hun; Heo, Serim; Park, Minwon; Yu, In-Keun; Kim, Hak-Man

    2013-01-01

    This paper analyzes the operating characteristics of a superconducting magnetic energy storage (SMES) for the frequency control of an islanded microgrid operation. In the grid-connected mode of a microgrid, an imbalance between power supply and demand is solved by a power trade with the upstream power grid. The difference in the islanded mode is a critical problem because the microgrid is isolated from any power grid. For this reason, the frequency control during islanded microgrid operation is a challenging issue. A test microgrid in this paper consisted of a wind power generator, a PV generation system, a diesel generator and a load to test the feasibility of the SMES for controlling frequency during islanded operation as well as the transient state varying from the grid-connected mode to the islanded mode. The results show that the SMES contributes well for frequency control in the islanded operation. In addition, a dual and a single magnet type of SMES have been compared to demonstrate the control performance. The dual magnet has the same energy capacity as the single magnet, but there are two superconducting coils and each coil has half inductance of the single magnet. The effectiveness of the SMES application with the simulation results is discussed in detail.

  14. Shift control method for the local time at descending node based on sun-synchronous orbit satellite

    Institute of Scientific and Technical Information of China (English)

    Yang Yong'an; Feng Zuren; Sun Linyan; Tan Wei

    2009-01-01

    This article analyzes the shift factors of the descending node local time for sun-synchronous satellites and proposes a shift control method to keep the local time shift within an allowance range. It is found that the satellite orbit design and the orbit injection deviation are the causes for the initial shift velocity, whereas the atmospheric drag and the sun gravitational perturbation produce the shift acceleration. To deal with these shift factors, a shift control method is put forward, through such methods as orbit variation design, orbit altitude, and inclination keeping control. The simulation experiment and practical application have proved the effectiveness of this control method.

  15. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  16. Integrated Robot-Human Control in Mining Operations

    Energy Technology Data Exchange (ETDEWEB)

    George Danko

    2007-09-30

    This report contains a detailed description of the work conducted for the project on Integrated Robot-Human Control in Mining Operations at University of Nevada, Reno. This project combines human operator control with robotic control concepts to create a hybrid control architecture, in which the strengths of each control method are combined to increase machine efficiency and reduce operator fatigue. The kinematics reconfiguration type differential control of the excavator implemented with a variety of 'software machine kinematics' is the key feature of the project. This software re-configured excavator is more desirable to execute a given digging task. The human operator retains the master control of the main motion parameters, while the computer coordinates the repetitive movement patterns of the machine links. These repetitive movements may be selected from a pre-defined family of trajectories with different transformations. The operator can make adjustments to this pattern in real time, as needed, to accommodate rapidly-changing environmental conditions. A working prototype has been developed using a Bobcat 435 excavator. The machine is operational with or without the computer control system depending on whether the computer interface is on or off. In preparation for emulated mining tasks tests, typical, repetitive tool trajectories during surface mining operations were recorded at the Newmont Mining Corporation's 'Lone Tree' mine in Nevada. Analysis of these working trajectories has been completed. The motion patterns, when transformed into a family of curves, may serve as the basis for software-controlled machine kinematics transformation in the new human-robot control system. A Cartesian control example has been developed and tested both in simulation and on the experimental excavator. Open-loop control is robustly stable and free of short-term dynamic problems, but it allows for drifting away from the desired motion kinematics of the

  17. Operational Satellite Based Flood Mapping Using the Delft-FEWS System

    Science.gov (United States)

    Westerhoff, Rogier; Huizinga, Jan; Kleuskens, Marco; Burren, Richard; Casey, Simon

    2010-12-01

    Reliable and timely information is essential for appropriate flood management. This article describes a probabilistic method to assess flood extent from SAR data. The article also addresses the derivation of flood levels and flood depth based on probabilistic flood extents and SRTM. The methods are tested on Envisat ASAR images in a hydrological open standard IT platform (Delft-FEWS). Providing flood extent maps in terms of probabilities using multiple angle data offers advantages for operational purposes, like major improvement of revisit time from 35 to 1-2 days, weighted merging of various data sources (in-situ, optical and SAR) and uncertainty propagation in models. Using medium or high resolution SAR data instead of 1x1 km pixels and using high resolution digital terrain model instead of SRTM data are important recommendations.

  18. An improved automated procedure for informal and temporary dwellings detection and enumeration, using mathematical morphology operators on VHR satellite data

    Science.gov (United States)

    Jenerowicz, Małgorzata; Kemper, Thomas

    2016-10-01

    Every year thousands of people are displaced by conflicts or natural disasters and often gather in large camps. Knowing how many people have been gathered is crucial for an efficient relief operation. However, it is often difficult to collect exact information on the total number of the population. This paper presents the improved morphological methodology for the estimation of dwellings structures located in several Internally Displaced Persons (IDPs) Camps, based on Very High Resolution (VHR) multispectral satellite imagery with pixel sizes of 1 meter or less including GeoEye-1, WorldView-2, QuickBird-2, Ikonos-2, Pléiades-A and Pléiades-B. The main topic of this paper is the approach enhancement with selection of feature extraction algorithm, the improvement and automation of pre-processing and results verification. For the informal and temporary dwellings extraction purpose the high quality of data has to be ensured. The pre-processing has been extended by including the input data hierarchy level assignment and data fusion method selection and evaluation. The feature extraction algorithm follows the procedure presented in Jenerowicz, M., Kemper, T., 2011. Optical data are analysed in a cyclic approach comprising image segmentation, geometrical, textural and spectral class modeling aiming at camp area identification. The successive steps of morphological processing have been combined in a one stand-alone application for automatic dwellings detection and enumeration. Actively implemented, these approaches can provide a reliable and consistent results, independent of the imaging satellite type and different study sites location, providing decision support in emergency response for the humanitarian community like United Nations, European Union and Non-Governmental relief organizations.

  19. Investigation of a possible control by Saturn satellites of auroral kilometric radiation

    Science.gov (United States)

    Boudjada, M. Y.; Galopeau, P. H. M.; Rucker, H. O.

    2013-09-01

    We attempt in this contribution to investigate the possible control of the Saturnian kilometric radiation by the planet's satellites. We use the observation of the Radio and Plasma Wave Science (RPWS) onboard the Cassini spacecraft. We consider the variation of the flux density versus the observation in time and frequency. The auroral kilometric emissions of Saturn are recorded in the frequency band from few kilohertz up to 1 MHz. The investigated period started from 01 Jan. 2004 to 31 Dec. 2007. We distinguish in this analysis between different Saturnian 'sources' which can be recognized by their spectral characteristics. We define two kinds of arc structures: the 'vertex early arcs' (VEA) and the 'vertex late arcs' (VLA). The arcs of the first group set open toward increasing time, while the arcs of the other one open towards decreasing time. A total of 556 arcs have been observed during the four investigated years, where 310 and 246 correspond, respectively, to the vertex early and late arcs. We show how the occurrence of arcs may be related to the position of the satellite around the planet Saturn. We emphasis in this analysis on the eventual control of the Saturnian kilometric radiation by Titan. Our results are compared with previous investigations performed by Daigne et al. (1982) and Kurth et al. (2006) using, respectively, Voyager and Cassini observations.

  20. Simultaneous state and actuator fault estimation for satellite attitude control systems

    Institute of Scientific and Technical Information of China (English)

    Cheng Yao; Wang Rixin; Xu Minqiang; Li Yuqing

    2016-01-01

    In this paper, a new nonlinear augmented observer is proposed and applied to satellite attitude control systems. The observer can estimate system state and actuator fault simultaneously. It can enhance the performances of rapidly-varying faults estimation. Only original system matrices are adopted in the parameter design. The considered faults can be unbounded, and the proposed augmented observer can estimate a large class of faults. Systems without disturbances and the fault whose finite times derivatives are zero piecewise are initially considered, followed by a discussion of a general situation where the system is subject to disturbances and the finite times derivatives of the faults are not null but bounded. For the considered nonlinear system, convergence conditions of the observer are provided and the stability analysis is performed using Lyapunov direct method. Then a feasible algorithm is explored to compute the observer parameters using linear matrix inequalities (LMIs). Finally, the effectiveness of the proposed approach is illustrated by considering an example of a closed-loop satellite attitude control system. The simulation results show satisfactory perfor-mance in estimating states and actuator faults. It also shows that multiple faults can be estimated successfully.

  1. Robot Control Based On Spatial-Operator Algebra

    Science.gov (United States)

    Rodriguez, Guillermo; Kreutz, Kenneth K.; Jain, Abhinandan

    1992-01-01

    Method for mathematical modeling and control of robotic manipulators based on spatial-operator algebra providing concise representation and simple, high-level theoretical frame-work for solution of kinematical and dynamical problems involving complicated temporal and spatial relationships. Recursive algorithms derived immediately from abstract spatial-operator expressions by inspection. Transition from abstract formulation through abstract solution to detailed implementation of specific algorithms to compute solution greatly simplified. Complicated dynamical problems like two cooperating robot arms solved more easily.

  2. Control, Operator Support and Safety System of PVC-reactors

    Directory of Open Access Journals (Sweden)

    Jens I. Ytreeide

    1997-01-01

    Full Text Available In modern petrochemical plants the corporate and societal demands to plant safety and minimum environmental effects are high. These demands rise high performance requirements to the technical systems, specially the process control and safety systems including an effective operator support system with fault detection capability. The systems must have high reliability also against erroneous operations which may cause shutdown situations or quality deviations.

  3. OPERATIONAL AND STRATEGIC CONTROLLING TOOLS IN MICROENTERPRISES – CASE STUDY

    Directory of Open Access Journals (Sweden)

    Justyna KONSEK-CIECHOŃSKA

    2017-10-01

    Full Text Available Globalisation and increasing requirements of the environment cause the executives and supervisors to search for more and more perfect solutions, allowing them to streamline and improve the effectiveness of company operations. One of such tools, used more and more often, is controlling, the role of which has substantially increased in the recent years. It is already implemented not only in large companies with foreign capital, but also in increasingly smaller entities, which begin to notice the positive effects of the implications of the principles and tools of controlling - both operational and strategic. The purpose of the article is to demonstrate the practical side of controlling tools that can be used for the purposes of operations conducted by microenterprises.

  4. Forces required to operate controls on farm tractors: implications for young operators.

    Science.gov (United States)

    Fathallah, F A; Chang, J H; Berg, R L; Pickett, W; Marlenga, B

    2008-07-01

    Farm tractors account for the majority of fatal injuries to adolescents working in agriculture and therefore remain a leading occupational priority. The question of whether these injuries occur because adolescents are assigned tractor jobs beyond their physical capabilities has not been answered. The purpose of this study was to estimate the activation forces required to operate controls on 40 tractors in common use in the US and compare them with existing estimates of physical strength for children of varying ages and with recommended ergonomic force limits for repeatedly engaging controls. Activation forces for steering, brakes and clutch were measured on each tractor. The main study finding was that the activation forces required to operate tractors typically exceeded the physical abilities of most children aged 13 to 17 years. This raises serious questions about the ability of children to safely operate tractors in common use on US farms. This study provides an ergonomic approach for evaluating the potential mismatch between young people's strength capabilities and forces required in operating farm tractors. This approach could be used in similar situations where adolescents may operate vehicles (e.g. all-terrain vehicles), machinery or other mechanical devices requiring activation of levers and controls. Study findings potentially inform the establishment of occupational policies surrounding tractor operation by young people.

  5. Feasibility of touch-less control of operating room lights.

    Science.gov (United States)

    Hartmann, Florian; Schlaefer, Alexander

    2013-03-01

    Today's highly technical operating rooms lead to fairly complex surgical workflows where the surgeon has to interact with a number of devices, including the operating room light. Hence, ideally, the surgeon could direct the light without major disruption of his work. We studied whether a gesture tracking-based control of an automated operating room light is feasible. So far, there has been little research on control approaches for operating lights. We have implemented an exemplary setup to mimic an automated light controlled by a gesture tracking system. The setup includes a articulated arm to position the light source and an off-the-shelf RGBD camera to detect the user interaction. We assessed the tracking performance using a robot-mounted hand phantom and ran a number of tests with 18 volunteers to evaluate the potential of touch-less light control. All test persons were comfortable with using the gesture-based system and quickly learned how to move a light spot on flat surface. The hand tracking error is direction-dependent and in the range of several centimeters, with a standard deviation of less than 1 mm and up to 3.5 mm orthogonal and parallel to the finger orientation, respectively. However, the subjects had no problems following even more complex paths with a width of less than 10 cm. The average speed was 0.15 m/s, and even initially slow subjects improved over time. Gestures to initiate control can be performed in approximately 2 s. Two-thirds of the subjects considered gesture control to be simple, and a majority considered it to be rather efficient. Implementation of an automated operating room light and touch-less control using an RGBD camera for gesture tracking is feasible. The remaining tracking error does not affect smooth control, and the use of the system is intuitive even for inexperienced users.

  6. Prophylactic digitalization fails to control dysrhythmia in thoracic esophageal operations.

    Science.gov (United States)

    Ritchie, A J; Tolan, M; Whiteside, M; McGuigan, J A; Gibbons, J R

    1993-01-01

    A prospective, controlled, randomized study of 80 patients undergoing esophageal operations was undertaken, in which one group of patients was given digoxin and the other was not. The incidence of cardiac dysrhythmia was compared in each group. Twenty-six patients underwent operation for benign disease. Equal numbers were digitalized or not and no dysrhythmias occurred. Fifty-four patients underwent operation for malignant disease. Of 26 in the group digitalized, 12 suffered dysrhythmia (46%). Of 28 not digitalized, 9 suffered dysrhythmia (32%). Overall, 39% of patients with malignant disease suffered a dysrhythmia compared with none with benign disease (p < 0.002 by chi 2).

  7. Distributed Motor Controller (DMC) for Operation in Extreme Environments

    Science.gov (United States)

    McKinney, Colin M.; Yager, Jeremy A.; Mojarradi, Mohammad M.; Some, Rafi; Sirota, Allen; Kopf, Ted; Stern, Ryan; Hunter, Don

    2012-01-01

    This paper presents an extreme environment capable Distributed Motor Controller (DMC) module suitable for operation with a distributed architecture of future spacecraft systems. This motor controller is designed to be a bus-based electronics module capable of operating a single Brushless DC motor in extreme space environments: temperature (-120 C to +85 C required, -180 C to +100 C stretch goal); radiation (>;20K required, >;100KRad stretch goal); >;360 cycles of operation. Achieving this objective will result in a scalable modular configuration for motor control with enhanced reliability that will greatly lower cost during the design, fabrication and ATLO phases of future missions. Within the heart of the DMC lies a pair of cold-capable Application Specific Integrated Circuits (ASICs) and a Field Programmable Gate Array (FPGA) that enable its miniaturization and operation in extreme environments. The ASICs are fabricated in the IBM 0.5 micron Silicon Germanium (SiGe) BiCMOS process and are comprised of Analog circuitry to provide telemetry information, sensor interface, and health and status of DMC. The FPGA contains logic to provide motor control, status monitoring and spacecraft interface. The testing and characterization of these ASICs have yielded excellent functionality in cold temperatures (-135 C). The DMC module has demonstrated successful operation of a motor at temperature.

  8. Distributed control of uncertain systems using superpositions of linear operators.

    Science.gov (United States)

    Sanger, Terence D

    2011-08-01

    Control in the natural environment is difficult in part because of uncertainty in the effect of actions. Uncertainty can be due to added motor or sensory noise, unmodeled dynamics, or quantization of sensory feedback. Biological systems are faced with further difficulties, since control must be performed by networks of cooperating neurons and neural subsystems. Here, we propose a new mathematical framework for modeling and simulation of distributed control systems operating in an uncertain environment. Stochastic differential operators can be derived from the stochastic differential equation describing a system, and they map the current state density into the differential of the state density. Unlike discrete-time Markov update operators, stochastic differential operators combine linearly for a large class of linear and nonlinear systems, and therefore the combined effects of multiple controllable and uncontrollable subsystems can be predicted. Design using these operators yields systems whose statistical behavior can be specified throughout state-space. The relationship to Bayesian estimation and discrete-time Markov processes is described.

  9. Nuclear electric power safety, operation, and control aspects

    CERN Document Server

    Knowles, J Brian

    2013-01-01

    Assesses the engineering of renewable sources for commercial power generation and discusses the safety, operation, and control aspects of nuclear electric power From an expert who advised the European Commission and UK government in the aftermath of Three Mile Island and Chernobyl comes a book that contains experienced engineering assessments of the options for replacing the existing, aged, fossil-fired power stations with renewable, gas-fired, or nuclear plants. From geothermal, solar, and wind to tidal and hydro generation, Nuclear Electric Power: Safety, Operation, and Control Aspects ass

  10. Decomposing Objectives and Functions in Power System Operation and Control

    DEFF Research Database (Denmark)

    Heussen, Kai; Lind, Morten

    2009-01-01

    mix of challenges posed by renewable energy sources, demand response technologies and smartgrid concepts, affecting all areas of power system operation. Both, new control modes and changes in market design are required. This paper presents a mean-ends perspective to the analysis of the control...... way. Finally, the discussion is opened up toward a formalization of service-exchange between market participants.......The introduction of many new energy solutions requires the adaptation of classical operation paradigms in power systems. In the standard paradigm, a power system is some equivalent of a synchronous generators, a power line and an uncontrollable load. This paradigm has been challenged by a diverse...

  11. User-oriented data acquisition chain task planning algorithm for operationally responsive space satellite

    Institute of Scientific and Technical Information of China (English)

    Hao Chen; Jun Li; Ning Jing

    2016-01-01

    With the development of operational y responsive space (ORS) and on-board processing techniques, the end users can receive the observation data from the ORS satel ite directly. To satisfy the demand for reducing the requirements-tasking-effects cycle from one day to hours, the various resources of the whole data acquisition chain (including satel ites, ground stations, data processing centers, users, etc.) should be taken into an overal consideration, and the traditional batch task planning mode should be transformed into the user-oriented task planning mode. Con-sidering there are many approaches for data acquisition due to the new techniques of ORS satel ite, the data acquisition chain task planning problem for ORS satel ite can be seen as the multi-modal route planning problem. Thereby, a framework is presented using label-constrained shortest path technique with the conflict resolution. To apply this framework to solve the ORS satel ite task planning problem, the preprocessing and the conflict resolution strategies are discussed in detail. Based on the above work, the user-oriented data acquisition chain task planning algorithm for ORS satel ite is proposed. The exact solution can be obtained in polynomial time using the proposed algorithm. The simulation experiments validate the feasibility and the adaptability of the pro-posed approach.

  12. Assimilation of Satellite Altimetry into a Western North Pacific Operational Model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An ocean data assimilation system, COMPASS-K (the Comprehensive Ocean Modeling, Prediction, Analysis and Synthesis System in the Kuroshio-region), has been developed at the Meteorological Research Institute (MRI). The purposes of the development are understanding ocean variability in the Kuroshio re gion as a local response to a global climate change with assimilated four-dimensional data sets, develop ment of an operational system in the Japan Meteorological Agency, and for the GODAE (Global Ocean Data Assimilation Experiment) project. The model is an eddy permitting version of an MRI-OGCM. Space-time decorrelation scales of ocean variability are estimated with TOPEX/POSEIDON (T/P) altimeter data. Subsurface temperature and salinity fields are projected from the T / P altimeter data with a statistical correlation method and are assim ilated into the model with a time-retrospective nudging scheme. Seasonal variation in the western North Pacific is investigated. Realistic space-time distribution of the physical quantities, the path of Kuroshio and its separation from Honshu are captured well. The Kuroshio volume transport is well reproduced in a reanalysis experiment of 1993. Preliminary predictability experi ments are done in February and March, 1994. Predictability diagram shows the time scale of the predictability for temperature field is about 17 days in the Kuroshio south of Japan. This time scale is smal ler than that in the North Atlantic.

  13. Rectification of single and multiple frames of satellite scanner imagery using points and edges as control

    Science.gov (United States)

    Paderes, F. C., Jr.; Mikhail, E. M.; Foerstner, W.

    1984-01-01

    Rectification of single and overlapping multiple scanner frames produced by such satellite-borne scanners as the LANDSAT MSS was carried out using a newly developed comprehensive parametric model. Tests with both simulated and real image data demonstrate conclusively that this model in general is superior to the widely used polynomial model, and that the simultaneous rectification of overlapping frames using least squares techniques yields a high accuracy than sngle frame rectification due to the inclusion of tie points between the image frames. Used to control, edges or lines, whic are much more likely to be found in images, can replace conventional control points and can easily be implemented into the least squares approach. An efficient algorithm for findng corresponding points in image paris was developed which can be used for determining tie points between image frames and thus increase the ecnomy of the whole rectification procedure.

  14. Analysis of broadcasting satellite service feeder link power control and polarization

    Science.gov (United States)

    Sullivan, T. M.

    1982-01-01

    Statistical analyses of carrier to interference power ratios (C/Is) were performed in assessing 17.5 GHz feeder links using (1) fixed power and power control, and (2) orthogonal linear and orthogonal circular polarizations. The analysis methods and attenuation/depolarization data base were based on CCIR findings to the greatest possible extent. Feeder links using adaptive power control were found to neither cause or suffer significant C/I degradation relative to that for fixed power feeder links having similar or less stringent availability objectives. The C/Is for sharing between orthogonal linearly polarized feeder links were found to be significantly higher than those for circular polarization only in links to nominally colocated satellites from nominally colocated Earth stations in high attenuation environments.

  15. Multilayer Control for Inverters in Parallel Operation without Intercommunications

    DEFF Research Database (Denmark)

    Hua, Ming; Hu, Haibing; Xing, Yan;

    2012-01-01

    among the inverters. The second layer is designed to compensate the voltage deviations caused by the mentioned droop control, thus improving the load-voltage regulation of the system. The third layer is a quasi-synchronization control aiming to roughly adjust the angle of the inverter to be close......In this paper, a multilayer control is proposed for inverters able to operate in parallel without intercommunications. The first control layer is an improved droop method that introduces power proportional terms into the conventional droop scheme, letting both active and reactive power to be shared...

  16. Simulator design for advanced ISDN satellite design and experiments

    Science.gov (United States)

    Pepin, Gerald R.

    1992-01-01

    This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) program, moves all control and switching functions on-board the next generation ISDN communication satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete events simulation experiments will be performed with these models using various traffic scenarios, design parameters and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  17. Grande Ronde Endemic Spring Chinook Salmon Supplementation Program; Satellite Facilities Operation and Maintenance, 2005 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    McLean, Michael L.; Seeger, Ryan; Hewitt, Laurie (Confederated Tribes of the Umatilla Indian Reservation, Department of Natural Resources, Pendleton, OR)

    2006-01-01

    prompting an early release. The total mortality for the acclimation period was 49 (0.05 %). The total number of fish released from the acclimation facility during the late period was 105,369. Maintenance and repair activities were conducted at the acclimation facilities in 2005. Facility maintenance work consisted of snow removal, installation of drainage lines, removal of gravel from intake area, installation of new gate at the CCAF, and complete overhaul of 2 travel trailers. The Catherine Creek Adult Capture Facility (CCACF) was put into operation on 11 February 2005. The first adult summer steelhead was captured on 4 March. A total of 190 adult summer steelhead were trapped and released from 4 March to 16 May 2005. Peak arrival at the trap was the week of 8 April. The first adult spring Chinook salmon was captured at CCACF on 6 May 2005. A total of 226 spring Chinook salmon were trapped from 6 May to 8 July 2005. There were 56 adults and 4 jacks unmarked and 136 adult and 30 jack marked spring Chinook salmon trapped. Peak arrival at the trap was the week of 10 June for the unmarked and marked fish. None of the captive broodstock returns were collected for broodstock. Broodstock was collected systematically over the entire return from 31 May to 6 July 2005. Ten of the 34 broodstock collected and transported from CCACF to LGH were unmarked fish trapped. About 18% of the naturally produced adult males and females trapped were taken to LGH for broodstock. One jack was collected for every 5 adult males that were taken to LGH. A total of 30 age 4 and 5 and 4 age 3 fish were transported to LGH for broodstock. The hatchery component of the broodstock was 66.7%. Five weekly spawning surveys were conducted below the weir on Catherine Creek beginning 30 June 2005. During these surveys no live or dead fish were observed. The trap was removed from Catherine Creek on 3 August 2005. Temperatures at the CCACF ranged from -0.1 C on 14 February to 23.7 C on 21 July. The hourly

  18. Guidance, Navigation, and Control System for Maneuverable Pico-Satellites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A compact, low-power GN&C system is essential to the success of pico-satellite Automated Rendezvous and Docking (AR&D). Austin Satellite Design (ASD)...

  19. High Level Control Applications for SOLEIL Commissioning and Operation

    CERN Document Server

    Nadolski, Laurent S; Ho, Katy; Leclercq, Nicolas; Ounsy, Majid; Petit, Sylvain

    2005-01-01

    The SOLEIL control system, namely TANGO developed in collaboration with ESRF, is now mature and stable. TANGO has also been chosen now by several other laboratories. High-level control applications implemented in the control room for the storage ring, the two transfer lines, and the booster will be described in this paper. Three kinds of tools for commissioning are used. First the generic TANGO tools (alarms, simple graphical control applications), which allow us to control in a simple way any TANGO Device Server. Secondly a Matlab Middle Layer (adapted from ALS and SPEAR3): Matlab is fully interconnected with TANGO; it is used primarily for writing Physics control applications. Finally Globalscreen, a commercial SCADA software devoted for building operation applications has been selected (panels for controlling or displaying setpoint, readback values, status of equipments). In addition an overview of the historical and short-term databases for the accelerators will be given. They have been developed in house...

  20. Operation and control of large wind turbines and wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Thomsen, Kenneth (and others)

    2005-09-01

    This report is the final report of a Danish research project 'Operation and control of large wind turbines and wind farms'. The objective of the project has been to analyse and assess operational strategies and possibilities for control of different types of wind turbines and different wind farm concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have been simulated, where the power production is decreased to an optimum when taking loads and actual price of produced electricity into account. Dynamic models and control strategies for the wind farms have also been developed, with the aim to optimise the operation of the wind farms considering participation in power system control of power (frequency) and reactive power (voltage), maximise power production, keep good power quality and limit mechanical loads and life time consumption. The project developed models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept is based on pitch controlled wind turbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms when it was isolated from the main grid on a local grid. Also the possibility to use the available information from the wind turbine controllers to predict the wind speed has been investigated. The main idea has been to predict the wind speed at a wind turbine using up-wind measurements of the wind speed in another wind turbine. (au)

  1. Control of Cauchy System for an Elliptic Operator

    Institute of Scientific and Technical Information of China (English)

    G.MASSENGO MOPHOU; O.NAKOULIMA

    2009-01-01

    The control of a Cauchy system for an elliptic operator seems to be globally an open problem. In this paper, we analyze this problem using a regularization method which consists in viewing a singular problem as a limit of a family of well-posed problems. Following this analysis and assuming that the interior of considered convex is non-empty, we obtain a singular optimality system (S.O.S.) for the considered control problem.

  2. Operation and control of large wind turbines and wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Thomsen, Kenneth (and others)

    2005-09-01

    This report is the final report of a Danish research project 'Operation and control of large wind turbines and wind farms'. The objective of the project has been to analyse and assess operational strategies and possibilities for control of different types of wind turbines and different wind farm concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have been simulated, where the power production is decreased to an optimum when taking loads and actual price of produced electricity into account. Dynamic models and control strategies for the wind farms have also been developed, with the aim to optimise the operation of the wind farms considering participation in power system control of power (frequency) and reactive power (voltage), maximise power production, keep good power quality and limit mechanical loads and life time consumption. The project developed models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept is based on pitch controlled wind turbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms when it was isolated from the main grid on a local grid. Also the possibility to use the available information from the wind turbine controllers to predict the wind speed has been investigated. The main idea has been to predict the wind speed at a wind turbine using up-wind measurements of the wind speed in another wind turbine. (au)

  3. Ability of youth operators to reach farm tractor controls.

    Science.gov (United States)

    Fathallah, F A; Chang, J H; Pickett, W; Marlenga, B

    2009-06-01

    Farm tractor work is commonly assigned to young people on North American farms, where tractors account for the majority of deaths and major portions of non-fatal trauma to working youths. However, little is known about the potential mismatch between the anthropometric and physical characteristics of children and tractor characteristics. The purpose of this study was to evaluate the ability of children of varying ages and percentiles to reach major controls on 45 tractors in common use in the US. The main study finding was that many tractor controls, especially those that are hand-operated, may not be effectively reached by the majority of youth operators aged 12 to 16 years. The study raises further serious questions about the ability of children to safely operate tractors in common use on US farms and calls for reconsideration of age guidelines for the assignment of children to tractor work on farms. This study provides novel ergonomic evidence about the ability of children to reach controls inside agricultural tractor cabins. The approach could be applied in similar situations where youths may operate other vehicles or machines. Study findings support the establishment and refinement of policies and guidelines related to youth tractor operation.

  4. Operational controlling - a tool of translating strategy into action

    Directory of Open Access Journals (Sweden)

    2011-03-01

    Full Text Available . Enterprises have a lot of problems with realization their strategic aims in the fast changing and competitive business arena from many years. Effective execution of strategic plan needs its translating into action, task results and indicators of everyday activities. The success on the market is attainable by communicating strategic and operating goals on the each level of organizational structure and their connecting with budget of units or employee motivation. The scorecards balancing in finance, customer, process and development perspectives is very useful for pointing - what do we control with? or - what do we have to achieve? But doesn't answer to question about ways of enterprise managing. Main aim of the article is proving that operational controlling system is a essential tool for translating strategy into action. The Balanced Scorecard methodology should to take into consideration system and process connection of enterprise with procurement, co-operation or distribution supply chain also.

  5. Control Operator for the Two-Dimensional Energized Wave Equation

    Directory of Open Access Journals (Sweden)

    Sunday Augustus REJU

    2006-07-01

    Full Text Available This paper studies the analytical model for the construction of the two-dimensional Energized wave equation. The control operator is given in term of space and time t independent variables. The integral quadratic objective cost functional is subject to the constraint of two-dimensional Energized diffusion, Heat and a source. The operator that shall be obtained extends the Conjugate Gradient method (ECGM as developed by Hestenes et al (1952, [1]. The new operator enables the computation of the penalty cost, optimal controls and state trajectories of the two-dimensional energized wave equation when apply to the Conjugate Gradient methods in (Waziri & Reju, LEJPT & LJS, Issues 9, 2006, [2-4] to appear in this series.

  6. Mold Heating and Cooling Pump Package Operator Interface Controls Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Josh A. Salmond

    2009-08-07

    The modernization of the Mold Heating and Cooling Pump Package Operator Interface (MHC PP OI) consisted of upgrading the antiquated single board computer with a proprietary operating system to off-the-shelf hardware and off-the-shelf software with customizable software options. The pump package is the machine interface between a central heating and cooling system that pumps heat transfer fluid through an injection or compression mold base on a local plastic molding machine. The operator interface provides the intelligent means of controlling this pumping process. Strict temperature control of a mold allows the production of high quality parts with tight tolerances and low residual stresses. The products fabricated are used on multiple programs.

  7. Three controllable factors of steady operation of EGSB reactor

    Institute of Scientific and Technical Information of China (English)

    LI Hui-li; LU Bing-nan; LI Fang

    2008-01-01

    The bench- scale EGSB (expanded granular sludge bed) reactor was operated to study the effect of sludge loading rate, pH value and nutrient element on the operation of the EGSB reactor and the control rule of these factors. Continuous flow was used to treat synthetic wastewater containing dextrose and beer, and the temperature of reactor was controlled at mesophiles temperature (33 ℃). The experimental results demonstrated trolled by adding sodium bicarbonate, the proper additive quantity was 1000-1200 mg/L; the additive quantity wastewater with 400-5000 mg/L COD concentration. The COD removal efficiency was over 85%. The operation of the EGSB reactor was steady and the EGSB reactor had strong anti-shock load ability.

  8. CNC Turning Center Advanced Operations. Computer Numerical Control Operator/Programmer. 444-332.

    Science.gov (United States)

    Skowronski, Steven D.; Tatum, Kenneth

    This student guide provides materials for a course designed to introduce the student to the operations and functions of a two-axis computer numerical control (CNC) turning center. The course consists of seven units. Unit 1 presents course expectations and syllabus, covers safety precautions, and describes the CNC turning center components, CNC…

  9. CNC Turning Center Advanced Operations. Computer Numerical Control Operator/Programmer. 444-332.

    Science.gov (United States)

    Skowronski, Steven D.; Tatum, Kenneth

    This student guide provides materials for a course designed to introduce the student to the operations and functions of a two-axis computer numerical control (CNC) turning center. The course consists of seven units. Unit 1 presents course expectations and syllabus, covers safety precautions, and describes the CNC turning center components, CNC…

  10. Robust Nonlinear Control with Compensation Operator for a Peltier System

    Directory of Open Access Journals (Sweden)

    Sheng-Jun Wen

    2014-01-01

    Full Text Available Robust nonlinear control with compensation operator is presented for a Peltier actuated system, where the compensation operator is designed by using a predictive model on heat radiation. For the Peltier system, the heat radiation is related to the fourth power of temperature. So, the heat radiation is affected evidently by the temperature when it is high and temperature difference between the system and environment is large. A new nonlinear model with the heat radiation is set up for the system according to some thermal conduction laws. To ensure robust stability of the nonlinear system, operator based robust right coprime factorization design is considered. Also, a compensation operator based on a predictive model is proposed to cancel effect of the heat radiation, where the predictive model is set up by using radial basis kernel function based SVM (support vector machine method. Finally, simulation results are given to show the effectiveness of the proposed scheme.

  11. A spatial operator algebra for manipulator modeling and control

    Science.gov (United States)

    Rodriguez, G.; Kreutz, K.; Milman, M.

    1988-01-01

    A powerful new spatial operator algebra for modeling, control, and trajectory design of manipulators is discussed along with its implementation in the Ada programming language. Applications of this algebra to robotics include an operator representation of the manipulator Jacobian matrix; the robot dynamical equations formulated in terms of the spatial algebra, showing the complete equivalence between the recursive Newton-Euler formulations to robot dynamics; the operator factorization and inversion of the manipulator mass matrix which immediately results in O(N) recursive forward dynamics algorithms; the joint accelerations of a manipulator due to a tip contact force; the recursive computation of the equivalent mass matrix as seen at the tip of a manipulator; and recursive forward dynamics of a closed chain system. Finally, additional applications and current research involving the use of the spatial operator algebra are discussed in general terms.

  12. MIMO Self-Tuning Control of Chemical Process Operation

    DEFF Research Database (Denmark)

    Hallager, L.; Jørgensen, S. B.; Goldschmidt, L.

    1984-01-01

    The problem of selecting a feasible model structure for a MIMO self-tuning controller (MIMOSC) is addressed. The dependency of the necessary structure complexity in relation to the specific process operating point is investigated. Experimental results from a fixed-bed chemical reactor are used...

  13. Fault tolerant wind turbine production operation and shutdown (Sustainable Control)

    NARCIS (Netherlands)

    Van Engelen, T.; Schuurmans, J.; Kanev, S.; Dong, J.; Verhaegen, M.H.G.; Hayashi, Y.

    2011-01-01

    Extreme environmental conditions as well as system failure are real-life phenomena. Especially offshore, extreme environmental conditions and system faults are to be dealt with in an effective way. The project Sustainable Control, a new approach to operate wind turbines (Agentschap NL, grant EOSLT02

  14. Formation Flying Satellite Control Around the L2 Sun-Earth Libration Point

    Science.gov (United States)

    Hamilton, Nicholas H.

    2001-12-01

    A growing interest in formation flying satellites demands development and analysis of control and estimation algorithms for station-keeping and formation maneuvering. This thesis discusses the development of a discrete linear-quadratic- regulator control algorithm for formations in the vicinity of the L2 sun-earth libration point. The development of an appropriate Kalman filter is included as well. Simulations are created for the analysis of the station-keeping and various formation maneuvers of the Stellar Imager mission. The simulations provide tracking error, estimation error, and control effort results. From the control effort, useful design parameters such as AV and propellant mass are determined. For formation maneuvering, the drone spacecraft track to within 4 meters of their desired position and within 1.3 millimeters per second of their desired zero velocity. The filter, with few exceptions, keeps the estimation errors within their three-sigma values. Without noise, the controller performs extremely well, with the drones tracking to within several micrometers. Bach drone uses around 1 to 2 grams of propellant per maneuver, depending on the circumstances.

  15. An advanced OBP-based payload operating in an asynchronous network for future data relay satellites utilising CCSDS-standard data structures

    Science.gov (United States)

    Grant, M.; Vernucci, A.

    1991-01-01

    A possible Data Relay Satellite System (DRSS) topology and network architecture is introduced. An asynchronous network concept, whereby each link (Inter-orbit, Inter-satellite, Feeder) is allowed to operate on its own clock, without causing loss of information, in conjunction with packet data structures, such as those specified by the CCSDS for advanced orbiting systems is discussed. A matching OBP payload architecture is described, highlighting the advantages provided by the OBP-based concept and then giving some indications on the OBP mass/power requirements.

  16. Toward a warfighter's associate: eliminating the operator control unit

    Science.gov (United States)

    Everett, Hobart R.; Pacis, Estrellina B.; Kogut, Greg; Farrington, Nathan M.; Khurana, S.

    2004-12-01

    In addition to the challenges of equipping a mobile robot with the appropriate sensors, actuators, and processing electronics necessary to perform some useful function, there coexists the equally important challenge of effectively controlling the system"s desired actions. This need is particularly critical if the intent is to operate in conjunction with human forces in a military application, as any low-level distractions can seriously reduce a warfighter"s chances of survival in hostile environments. Historically there can be seen a definitive trend towards making the robot smarter in order to reduce the control burden on the operator, and while much progress has been made in laboratory prototypes, all equipment deployed in theatre to date has been strictly teleoperated. There exists a definite tradeoff between the value added by the robot, in terms of how it contributes to the performance of the mission, and the loss of effectiveness associated with the operator control unit. From a command-and-control perspective, the ultimate goal would be to eliminate the need for a separate robot controller altogether, since it represents an unwanted burden and potential liability from the operator"s perspective. This paper introduces the long-term concept of a supervised autonomous Warfighter"s Associate, which employs a natural-language interface for communication with (and oversight by) its human counterpart. More realistic near-term solutions to achieve intermediate success are then presented, along with actual results to date. The primary application discussed is military, but the concept also applies to law enforcement, space exploration, and search-and-rescue scenarios.

  17. Multilayer control for inverters in parallel operation without signal interconnection

    DEFF Research Database (Denmark)

    Hua, Ming; Hu, Haibing; Xing, Yan;

    2011-01-01

    by adjusting the phase and amplitude of the output voltage respectively. The second layer is to compensate the droop voltage caused by the droop control and thus improve the load regulation performance of the inverter. The third layer limits the phase deviation between the inverter and the shared ac bus......A multilayer control is proposed for inverters with wireless parallel operation in this paper. The control is embedded in every inverter respectively and consists of three layers. The first layer is based on an improved droop method, which shares the active and reactive power in each module...

  18. Control, operator support and safety system of PVC reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ytreeide, J.I.; Aaker, O.; Kristoffersen, V.; Moe, G.; Naustdal, C.

    1997-06-01

    In modern petrochemical plants the corporate and societal demands to plant safety and minimum environmental effects are high. These demands rise high performance requirements to the technical systems, specially the process control and safety systems including an effective operator support system with fault detection capability. PVC producing plants have high inherent hazard potentials, and the studied reaction in this publication is exothermic and non-linear and open-loop unstable, and the plant is equipped with two independent cooling systems to keep the reaction under control. A system to solve the stability problem of parallel control is suggested, showing the simulation of real process data. The publication describes an operator support system for monitoring the heat of reaction in the autoclave consisting of a model based estimator. The system is tested on-line, and the results of simulations and on-line estimates are presented. 6 refs., 13 figs.

  19. Operational tools and applications of EO satellite data to retrieve surface fluxes in semi-arid countries

    Science.gov (United States)

    Tanguy, Maliko

    The objective of the thesis is to develop and evaluate useful tools and applications of Earth Observation (EO) satellite data to estimate surface fluxes in semi-arid countries. In a first part (Chapter 4), we assess the performance of a new parameterisation scheme of ground heat flux (G) to be used in remote sensing (RS) evapotranspiration (ET) estimation methods. The G-parameterisation optimized with AMMA flux data performs well and improves the sensible heat flux (H) and ET retrieved by means of the triangle method (Jiang & Islam, 2001). In a second part (Chapter 5), the triangle method is compared with ET estimated by means of a land surface model (JULES). An attempt is made to calibrate JULES using the triangle method through Monte Carlo simulations, but the two methods supply rather different results, indicating that further intercomparison tasks should be carried out to assess the performance of RS-based algorithms and land surface models in estimating the components of the land surface energy balance. Chapter 6 presents a set of operational examples for retrieving surface fluxes using RS data. The first example is the study of temporal evolution of ET-maps in Western Africa under monsoonal influence. In a second example, we apply the new scheme proposed in Chapter 4 to retrieve and analyse the long term evolution (2000-2009) of the surface energy balance components, G, H and ET at several sites of the Segura Basin (S-E Spain) using MODIS-Terra data (land surface temperature and NDVI). Temporal and spatial distribution of evapotranspiration reveals different controls on ET. (Chapter 6). In the last example, MODIS-Aqua Sea Surface Temperature (SST) is used to validate a mathematical model to retrieve surface fluxes in a Mediterranean coastal lagoon (Mar Menor, S-E Spain). El objetivo de esta tesis es de desarrollar y evaluar herramientas y aplicaciones de la teledetección para estimar flujos de superficie en zonas semiáridas. En una primera parte (Cap

  20. Cassini Attitude Control Operations Flight Rules and How They are Enforced

    Science.gov (United States)

    Burk, Thomas; Bates, David

    2008-01-01

    The Cassini spacecraft was launched on October 15, 1997 and arrived at Saturn on June 30, 2004. It has performed detailed observations and remote sensing of Saturn, its rings, and its satellites since that time. Cassini deployed the European-built Huygens probe which descended through the Titan atmosphere and landed on its surface on January 14, 2005. Operating the Cassini spacecraft is a complex scientific, engineering, and management job. In order to safely operate the spacecraft, a large number of flight rules were developed. These flight rules must be enforced throughout the lifetime of the Cassini spacecraft. Flight rules are defined as any operational limitation imposed by the spacecraft system design, hardware, and software, violation of which would result in spacecraft damage, loss of consumables, loss of mission objectives, loss and/or degradation of science, and less than optimal performance. Flight rules require clear description and rationale. Detailed automated methods have been developed to insure the spacecraft is continuously operated within these flight rules. An overview of all the flight rules allocated to the Cassini Attitude Control and Articulation Subsystem and how they are enforced is presented in this paper.

  1. Cassini Attitude Control Operations Flight Rules and How They are Enforced

    Science.gov (United States)

    Burk, Thomas; Bates, David

    2008-01-01

    The Cassini spacecraft was launched on October 15, 1997 and arrived at Saturn on June 30, 2004. It has performed detailed observations and remote sensing of Saturn, its rings, and its satellites since that time. Cassini deployed the European-built Huygens probe which descended through the Titan atmosphere and landed on its surface on January 14, 2005. Operating the Cassini spacecraft is a complex scientific, engineering, and management job. In order to safely operate the spacecraft, a large number of flight rules were developed. These flight rules must be enforced throughout the lifetime of the Cassini spacecraft. Flight rules are defined as any operational limitation imposed by the spacecraft system design, hardware, and software, violation of which would result in spacecraft damage, loss of consumables, loss of mission objectives, loss and/or degradation of science, and less than optimal performance. Flight rules require clear description and rationale. Detailed automated methods have been developed to insure the spacecraft is continuously operated within these flight rules. An overview of all the flight rules allocated to the Cassini Attitude Control and Articulation Subsystem and how they are enforced is presented in this paper.

  2. Preparing for JWST wavefront sensing and control operations

    Science.gov (United States)

    Perrin, Marshall D.; Acton, D. Scott; Lajoie, Charles-Philippe; Knight, J. Scott; Lallo, Matthew D.; Allen, Marsha; Baggett, Wayne; Barker, Elizabeth; Comeau, Thomas; Coppock, Eric; Dean, Bruce H.; Hartig, George; Hayden, William L.; Jordan, Margaret; Jurling, Alden; Kulp, Trey; Long, Joseph; McElwain, Michael W.; Meza, Luis; Nelan, Edmund P.; Soummer, Remi; Stansberry, John; Stark, Christopher; Telfer, Randal; Welsh, Andria L.; Zielinski, Thomas P.; Zimmerman, Neil T.

    2016-07-01

    The James Webb Space Telescopes segmented primary and deployable secondary mirrors will be actively con- trolled to achieve optical alignment through a complex series of steps that will extend across several months during the observatory's commissioning. This process will require an intricate interplay between individual wavefront sensing and control tasks, instrument-level checkout and commissioning, and observatory-level calibrations, which involves many subsystems across both the observatory and the ground system. Furthermore, commissioning will often exercise observatory capabilities under atypical circumstances, such as fine guiding with unstacked or defocused images, or planning targeted observations in the presence of substantial time-variable offsets to the telescope line of sight. Coordination for this process across the JWST partnership has been conducted through the Wavefront Sensing and Control Operations Working Group. We describe at a high level the activities of this group and the resulting detailed commissioning operations plans, supporting software tools development, and ongoing preparations activities at the Science and Operations Center. For each major step in JWST's wavefront sensing and control, we also explain the changes and additions that were needed to turn an initial operations concept into a flight-ready plan with proven tools. These efforts are leading to a robust and well-tested process and preparing the team for an efficient and successful commissioning of JWSTs active telescope.

  3. The control of satellites with microgravity constraints: The COMET Control System

    Science.gov (United States)

    Grossman, Walter; Freesland, Douglas

    1994-01-01

    The COMET attitude determination and control system, using inverse dynamics and a novel torque distribution/momentum management technique, has shown great flexibility, performance, and robustness. Three-axis control with two wheels is an inherent consequence of inverse dynamics control which allows for reduction in spacecraft weight and cost, or alternatively, provides a simple means of failure-redundancy for three-wheel spacecraft. The control system, without modification, has continued to perform well in spite of large changes in spacecraft mass properties and mission orbit altitude that have occurred during development. This flexibility has obviated imposition of early stringent ADACS design constraints and has greatly reduced commonly incurred ADACS modification costs and delay associated with program maturation.

  4. Operation assistance of a voice-controlled electric wheelchair

    Science.gov (United States)

    Asakawa, Takashi; Nishihara, Kazue

    2007-12-01

    We propose a voice-controlled electric wheelchair with a system for detecting its position and direction. Thus far, we have studied systems that incorporated voice instructions with our indoor navigation equipment using RF tags. The operability of a wheelchair was measured in the same environment for different operating methods. We found that one very effective method is to store the possible stopping positions and angles of rotation for the desired directions in RF cards, which could then adequately assist the movement of a wheelchair.

  5. Medical Command and Control in Sea-Based Operations

    Science.gov (United States)

    2006-01-01

    AND CONTROL IN SEA-BASED OPERATIONS Captain Arthur M. Smith, MC, U.S. Navy Reserve (Retired), and Captain Harold R. Bohman, MC, U.S. Navy Medical...Operation Desert Storm: Full Army Capability Not Achieved, GAO/NSIAD 92-175 (Washington, D.C.: 1992), p. 47. See also Arthur M. Smith, “Integrated...September 1976), pp. 694–703; Ron R. Rozin and Y. Kleinman , “Surgical Priorities of Abdominal Wounded in a Combat Situation,” Journal of Trauma 27, no. 6

  6. Advanced Transport Operating System (ATOPS) control display unit software description

    Science.gov (United States)

    Slominski, Christopher J.; Parks, Mark A.; Debure, Kelly R.; Heaphy, William J.

    1992-01-01

    The software created for the Control Display Units (CDUs), used for the Advanced Transport Operating Systems (ATOPS) project, on the Transport Systems Research Vehicle (TSRV) is described. Module descriptions are presented in a standardized format which contains module purpose, calling sequence, a detailed description, and global references. The global reference section includes subroutines, functions, and common variables referenced by a particular module. The CDUs, one for the pilot and one for the copilot, are used for flight management purposes. Operations performed with the CDU affects the aircraft's guidance, navigation, and display software.

  7. Microgrids and distributed generation systems: Control, operation, coordination and planning

    Science.gov (United States)

    Che, Liang

    Distributed Energy Resources (DERs) which include distributed generations (DGs), distributed energy storage systems, and adjustable loads are key components in microgrid operations. A microgrid is a small electric power system integrated with on-site DERs to serve all or some portion of the local load and connected to the utility grid through the point of common coupling (PCC). Microgrids can operate in both grid-connected mode and island mode. The structure and components of hierarchical control for a microgrid at Illinois Institute of Technology (IIT) are discussed and analyzed. Case studies would address the reliable and economic operation of IIT microgrid. The simulation results of IIT microgrid operation demonstrate that the hierarchical control and the coordination strategy of distributed energy resources (DERs) is an effective way of optimizing the economic operation and the reliability of microgrids. The benefits and challenges of DC microgrids are addressed with a DC model for the IIT microgrid. We presented the hierarchical control strategy including the primary, secondary, and tertiary controls for economic operation and the resilience of a DC microgrid. The simulation results verify that the proposed coordinated strategy is an effective way of ensuring the resilient response of DC microgrids to emergencies and optimizing their economic operation at steady state. The concept and prototype of a community microgrid that interconnecting multiple microgrids in a community are proposed. Two works are conducted. For the coordination, novel three-level hierarchical coordination strategy to coordinate the optimal power exchanges among neighboring microgrids is proposed. For the planning, a multi-microgrid interconnection planning framework using probabilistic minimal cut-set (MCS) based iterative methodology is proposed for enhancing the economic, resilience, and reliability signals in multi-microgrid operations. The implementation of high-reliability microgrids

  8. Attitude Control and Orbital Dynamics Challenges of Removing the First 3-Axis Stabilized Tracking and Data Relay Satellite from the Geosynchronous ARC

    Science.gov (United States)

    Benet, Charles A.; Hofman, Henry; Williams, Thomas E.; Olney, Dave; Zaleski, Ronald

    2011-01-01

    Launched on April 4, 1983 onboard STS 6 (Space Shuttle Challenger), the First Tracking and Data Relay Satellite (TDRS 1) was retired above the Geosynchronous Orbit (GEO) on June 27, 2010 after having provided real-time communications with a variety of low-orbiting spacecraft over a 26-year period. To meet NASA requirements limiting orbital debris 1, a team of experts was assembled to conduct an End-Of-Mission (EOM) procedure to raise the satellite 350 km above the GEO orbit. Following the orbit raising via conventional station change maneuvers, the team was confronted with having to deplete the remaining propellant and passivate all energy storage or generation sources. To accomplish these tasks within the time window, communications (telemetry and control links), electrical power, propulsion, and thermal constraints, a spacecraft originally designed as a three-axis stabilized satellite was turned into a spinner. This paper (a companion paper to Innovative Approach Enabled the Retirement of TDRS 1, paper # 1699, IEEE 2011 Aerospace Conference, March 5-12, 2011 sup 2) focuses on the challenges of maintaining an acceptable spinning dynamics, while repetitively firing thrusters. Also addressed are the effects of thruster firings on the orbit characteristics and how they were mitigated by a careful scheduling of the fuel depletion operations. Periodic thruster firings for spin rate adjustment, nutation damping, and precession of the momentum vector were also required in order to maintain effective communications with the satellite. All operations were thoroughly rehearsed and supported by simulations thus lending a high level of confidence in meeting the NASA EOM goals.

  9. Satellite and Aerial Remote Sensing in Support of Disaster Response Operations Conducted by the Texas Division of Emergency Management

    Science.gov (United States)

    Wells, G. L.; Tapley, B. D.; Bettadpur, S. V.; Howard, T.; Porter, B.; Smith, S.; Teng, L.; Tapley, C.

    2014-12-01

    The effective use of remote sensing products as guidance to emergency managers and first responders during field operations requires close coordination and communication with state-level decision makers, incident commanders and the leaders of individual strike teams. Information must be tailored to meet the needs of different emergency support functions and must contain current (ideally near real-time) data delivered in standard formats in time to influence decisions made under rapidly changing conditions. Since 2003, a representative of the University of Texas Center for Space Research (CSR) has served as a member of the Governor's Emergency Management Council and has directed the flow of information from remote sensing observations and high performance computing modeling and simulations to the Texas Division of Emergency Management in the State Operations Center. The CSR team has supported response and recovery missions resulting from hurricanes, tornadoes, flash floods, wildfires, oil spills and other natural and man-made disasters in Texas and surrounding states. Through web mapping services, state emergency managers and field teams have received threat model forecasts, real-time vehicle tracking displays and imagery to support search-and-clear operations before hurricane landfall, search-and-rescue missions following floods, tactical wildfire suppression, pollution monitoring and hazardous materials detection. Data servers provide near real-time satellite imagery collected by CSR's direct broadcast receiving system and post data products delivered during activations of the United Nations International Charter on Space and Major Disasters. In the aftermath of large-scale events, CSR is charged with tasking state aviation resources, including the Air National Guard and Texas Civil Air Patrol, to acquire geolocated aerial photography of the affected region for wide area damage assessment. A data archive for each disaster is available online for years following

  10. Preliminary Location Accuracy Assessments of 3rd Satellite of TH-1

    OpenAIRE

    2016-01-01

    The TH-1 satellite is the first stereo mapping transmission satellite in China, and the primary mission goal of the satellite is for topographic mapping at 1:50 000 scale and high-accuracy location without Ground Control Points (GCPs). 1st, 2nd satellites of TH-1 were launched on August 24, 2010, May 6, 2012, and 3rd satellite was launched on October 26, 2015. Now, three satellites of TH-1 are well operating on its orbit. After evaluation, the location accuracy of 1st satellite without GCPs i...

  11. Operator in-the-loop control of rotary cranes

    Energy Technology Data Exchange (ETDEWEB)

    Parker, G.G.; Robinett, R.D.; Driessen, B.J.; Dohrmann, C.R.

    1996-03-01

    An open-loop control method is presented for reducing the oscillatory motion of rotary crane payloads during operator commanded maneuvers. A typical rotary crane consists of a multiple degree-of-freedom platform for positioning a spherical pendulum with an attached payload. The crane operator positions the Payload by issuing a combination of translational and rotational commands to the platform as well as load-line length changes. Frequently, these pendulum modes are time-varying and exhibit low natural frequencies. Maneuvers are therefore performed at rates sufficiently slow so as not to excite oscillation. The strategy presented here generates crane commands which suppress vibration of the payload without a priori knowledge of the desired maneuver. Results are presented for operator in-the-loop positioning using a real-time dynamics simulation of a three-axis rotary crane where the residual sway magnitude is reduced in excess of 4OdB.

  12. Remote Synchronization Experiments for Quasi-Zenith Satellite System Using Multiple Navigation Signals as Feedback Control

    Directory of Open Access Journals (Sweden)

    Toshiaki Iwata

    2011-01-01

    Full Text Available The remote synchronization system for the onboard crystal oscillator (RESSOX is a remote control method that permits synchronization between a ground station atomic clock and Japanese quasi-zenith satellite system (QZSS crystal oscillators. To realize the RESSOX of the QZSS, the utilization of navigation signals of QZSS for feedback control is an important issue. Since QZSS transmits seven navigation signals (L1C/A, L1CP, L1CD, L2CM, L2CL, L5Q, and L5I, all combinations of these signals should be evaluated. First, the RESSOX algorithm will be introduced. Next, experimental performance will be demonstrated. If only a single signal is available, ionospheric delay should be input from external measurements. If multiple frequency signals are available, any combination, except for L2 and L5, gives good performance with synchronization error being within two nanoseconds that of RESSOX. The combination of L1CD and L5Q gives the best synchronization performance (synchronization error within 1.14 ns. Finally, in the discussion, comparisons of long-duration performance, computer simulation, and sampling number used in feedback control are considered. Although experimental results do not correspond to the simulation results, the tendencies are similar. For the overlapping Allan deviation of long duration, the stability of 1.23×10−14 at 100,160 s is obtained.

  13. Expert systems in power substation operation and control

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Guilherme Moutinho; Lambert-Torres, Germano; Silva, Alexandre P. Alves da [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    With digital technology being increasingly adopted in power substations (SE), perspectives are created for integration of supervision, control and protection systems in addition to making its process automation feasible. Once a SE is digitalized, the systems which previously were implemented physically will be able to be implemented by means of computer programs (software), allowing the expansion of its scope of operation. Studies and research performed at the international level have pointed to the utilization of Expert Systems (ES) as a more suitable alternative for representation and solution of the operation and control problems, especially those which do not have an established theory, which are provided with diagnosis characteristics and that associate themselves with fuzzy data and information. (author) 4 refs., 3 figs.

  14. New operator assistance features in the CMS Run Control System

    CERN Document Server

    Andre, Jean-marc Olivier; Branson, James; Brummer, Philipp Maximilian; Chaze, Olivier; Cittolin, Sergio; Contescu, Cristian; Craigs, Benjamin Gordon; Darlea, Georgiana Lavinia; Deldicque, Christian; Demiragli, Zeynep; Dobson, Marc; Doualot, Nicolas; Erhan, Samim; Fulcheri, Jonathan F; Gigi, Dominique; Michail Gl; adki; Glege, Frank; Gomez Ceballos, Guillelmo; Hegeman, Jeroen Guido; Holzner, Andre Georg; Janulis, Mindaugas; Jimenez Estupinan, Raul; Masetti, Lorenzo; Meijers, Franciscus; Meschi, Emilio; Mommsen, Remigius; Morovic, Srecko; O'Dell, Vivian; Orsini, Luciano; Paus, Christoph Maria Ernst; Petrova, Petia; Pieri, Marco; Racz, Attila; Reis, Thomas; Sakulin, Hannes; Schwick, Christoph; Simelevicius, Dainius; Zejdl, Petr

    2017-01-01

    The Run Control System of the Compact Muon Solenoid (CMS) experiment at CERN is a distributed Java web application running on Apache Tomcat servers. During Run-1 of the LHC, many operational procedures have been automated. When detector high voltages are ramped up or down or upon certain beam mode changes of the LHC, the DAQ system is automatically partially reconfigured with new parameters. Certain types of errors such as errors caused by single-event upsets may trigger an automatic recovery procedure. Furthermore, the top-level control node continuously performs cross-checks to detect sub-system actions becoming necessary because of changes in configuration keys, changes in the set of included front-end drivers or because of potential clock instabilities. The operator is guided to perform the necessary actions through graphical indicators displayed next to the relevant command buttons in the user interface. Through these indicators, consistent configuration of CMS is ensured. However, manually following t...

  15. Optically controlled multiple switching operations of DNA biopolymer devices

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu [Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Fruk, Ljiljana [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Hung, Yu-Chueh, E-mail: ychung@ee.nthu.edu.tw [Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2015-12-21

    We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices.

  16. Joint Forward Operating Base Elements of Command and Control

    Science.gov (United States)

    Summers, William C.

    2002-01-01

    Since the 1986 Goldwater-Nichols Act directed the Chairman of the Joint Chiefs of Staff to develop doctrine for the joint employment of the armed forces, tactics, techniques, and procedures have evolved at different rates depending on the competency. Whereas the command of joint air forces is well prescribed within the structure of the air operations center and its associated leadership, command of air assets at a joint forward operating base lacks guidance. Today, the United States prosecutes an air war over Afghanistan from bases in Uzbekistan, Pakistan, and Afghanistan. Elements of the United States Army, Air Force, and Marines combine at these geographically minute locations, each bringing a certain complement of support and command and control. Evidence from operations during the 1999 air war for Kosovo at Tirana Rinas Airport in Albania suggests that when these service elements meet at the airfield for the first time, there are problems associated with local procedure. At best, time is wasted creating local joint systems to overcome the difficulties. At worst, safety and mission accomplishment are jeopardized. This thesis will address the need to develop doctrine and a jointly integrated organization to support the command and control function at a forward operating base.

  17. ERROR-CONTROL CODING OF ADS-B MESSAGES FOR IRIDIUM SATELLITES

    Directory of Open Access Journals (Sweden)

    Volodymyr Kharchenko

    2013-12-01

    Full Text Available For modelling of ADS-B messages transmitting on the base of low-orbit satellite constellation Іrіdіum the model of a communication channel “Aircraft - Satellite - Ground Station” was built using MATLAB Sіmulіnk. This model allowed to investigate dependences of the Bit Error Rate on a type of  signal coding/decoding, ratio Eb/N0 and satellite repeater gain

  18. Robots for Field Operations with Comprehensive Multilayer Control

    OpenAIRE

    2013-01-01

    Today research within agricultural technology focuses beside productivity and operation costs mainly on increasing the resource efficiency of crop production. Autonomous machines have the potential to significantly contribute to this by utilizing more multi-factorial real-time sensing and embedding artificial intelligence. A multilayer controller has successfully been implemented on two outdoor machines with various implements to conduct several agricultural applications in autonomous mode. F...

  19. Neutral recirculation—the key to control of divertor operation

    Science.gov (United States)

    Kukushkin, A. S.; Pacher, H. D.

    2016-12-01

    Interaction of the plasma with neutral gas in the divertor affects virtually all aspects of divertor functionality (power loading of the targets, pumping and fuelling, sustaining the operational conditions of the core plasma). In the course of ITER design development, this interaction has been the subject of intense modelling analysis, supported by experiments on various tokamaks. Neutral gas puffing is found to be the most effective means of divertor control. The results of those studies are summarized and assessed in the paper.

  20. Response Times of Operators in a Control Room

    DEFF Research Database (Denmark)

    Platz, O.; Rasmussen, J.; Skanborg, Preben Zacho

    A statistical analysis was made of operator response times recorded in the control room of a research reactor during the years 1972-1974. A homogeneity test revealed that the data consist of a mixture of populations. A small but statistically significant difference is found between day and night ...... response times. Lognormal distributions are found to provide the best fit of the day and the night response times....

  1. Evaluation of Digital Checklists for Command and Control Operations

    Science.gov (United States)

    2016-01-01

    EVALUATION OF DIGITAL CHECKLISTS FOR COMMAND AND CONTROL OPERATIONS Christopher K. McClernon 1 , Victor S. Finomore 2 , Terence S. Andre 3...the potential effectiveness of a digital system that could take the place of the paper system that is currently being used. A between groups...assessments of each system were analyzed and compared. The data showed that a linear digital checklist takes a longer amount of time than both a paper

  2. Personnel Access Control System Evaluation for National Ignition Facility Operations

    Energy Technology Data Exchange (ETDEWEB)

    Altenbach, T; Brereton, S.; Hermes, G.; Singh, M.

    2001-06-01

    The purpose of this document is to analyze the baseline Access Control System for the National Ignition Facility (NIF), and to assess its effectiveness at controlling access to hazardous locations during full NIF operations. It reviews the various hazards present during a NIF shot sequence, and evaluates the effectiveness of the applicable set of controls at preventing access while the hazards are present. It considers only those hazards that could potentially be lethal. In addition, various types of technologies that might be applicable at NIF are reviewed, as are systems currently in use at other facilities requiring access control for safety reasons. Recommendations on how this system might be modified to reduce risk are made.

  3. Hierarchical Control for Optimal and Distributed Operation of Microgrid Systems

    DEFF Research Database (Denmark)

    Meng, Lexuan

    of the underlying communication features (sampling time, topology, parameters, etc.). System dynamics and sensitivity analysis are conducted based on the proposed model. A MG central controller is also developed based on the experimental system in the intelligent MG lab in Aalborg University for providing...... are also conducted in order to ensure safe operation during the optimization procedure. In addition, as the secondary and tertiary controls require global information to perform the functions, they are usually implemented in centralized fashion. In this sense the communication links are required from...... the central unit to each local unit, a single point of failure in the central controller may jerpodize the safety of the whole system, and the flexibility of the system is limited. Consequently, this project proposes the application of dynamic consensus algorithm (DCA) into existing hierarchical control...

  4. Satellite mobile data service for Canada

    Science.gov (United States)

    Egan, Glenn R.; Sward, David J.

    A commercial mobile satellite system which is to be constructed and operated in Canada is examined. This is done in two phases. First, mobile data services was introduced. Hub equipment and 3000 mobile data terminals were supplied. Over the satellite tests were performed. The mobile data service provides full two way digital messaging automatic vehicle location and fleet management services. The second phase is to construct, launch and make operational the MSAT satellite and associated network control facilities. The implementation is examined of the mobile data service in Canada, including the technical description. Marketing and applications are also examined.

  5. 47 CFR 90.471 - Points of operation in internal transmitter control systems.

    Science.gov (United States)

    2010-10-01

    ...) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Transmitter Control Internal Transmitter Control Systems § 90.471 Points of operation in internal transmitter control systems. The... licensee for internal communications and transmitter control purposes. Operating positions in...

  6. A series on optimizing satellite systems. I - Restoring interruptions of communications sattelite service: Logistical and cost comparisons of mature and newly operational systems

    Science.gov (United States)

    Snow, Marcellus S.

    1989-09-01

    A mathematical model is presented of costs and operational factors involved in provision for service interruptions of both a mature and typically large incumbent satellite system and of a smaller, more recently operational system. The equation expresses the required launch frequency for the new system as a function of the launch spacing of the mature system; the time disparity between the inauguration of the two systems; and the rate of capacity depreciation. In addition, a technique is presented to compare the relative extent to which the discounted costs of the new system exceed those of the mature system in furnishing the same effective capacity in orbit, and thus the same service liability, at a given point in time. It is determined that a mature incumbent communications satellite system, having more capacity in orbit, will on balance have a lower probability of service interruption than a newer, smaller system.

  7. Integrated Orbit, Attitude, and Structural Control Systems Design for Space Solar Power Satellites

    Science.gov (United States)

    Wie, Bong; Roithmayr, Carlos M.

    2001-01-01

    The major objective of this study is to develop an integrated orbit, attitude, and structural control systems architecture for very large Space Solar Power Satellites (SSPS) in geosynchronous orbit. This study focuses on the 1.2-GW Abacus SSPS concept characterized by a 3.2 x 3.2 km solar-array platform, a 500-m diameter microwave beam transmitting antenna, and a 500 x 700 m earth-tracking reflector. For this baseline Abacus SSPS configuration, we derive and analyze a complete set of mathematical models, including external disturbances such as solar radiation pressure, microwave radiation, gravity-gradient torque, and other orbit perturbation effects. The proposed control systems architecture utilizes a minimum of 500 1-N electric thrusters to counter, simultaneously, the cyclic pitch gravity-gradient torque, the secular roll torque caused by an offset of the center-of-mass and center-of-pressure, the cyclic roll/yaw microwave radiation torque, and the solar radiation pressure force whose average value is about 60 N.

  8. Nonlinear Burn Control and Operating Point Optimization in ITER

    Science.gov (United States)

    Boyer, Mark; Schuster, Eugenio

    2013-10-01

    Control of the fusion power through regulation of the plasma density and temperature will be essential for achieving and maintaining desired operating points in fusion reactors and burning plasma experiments like ITER. In this work, a volume averaged model for the evolution of the density of energy, deuterium and tritium fuel ions, alpha-particles, and impurity ions is used to synthesize a multi-input multi-output nonlinear feedback controller for stabilizing and modulating the burn condition. Adaptive control techniques are used to account for uncertainty in model parameters, including particle confinement times and recycling rates. The control approach makes use of the different possible methods for altering the fusion power, including adjusting the temperature through auxiliary heating, modulating the density and isotopic mix through fueling, and altering the impurity density through impurity injection. Furthermore, a model-based optimization scheme is proposed to drive the system as close as possible to desired fusion power and temperature references. Constraints are considered in the optimization scheme to ensure that, for example, density and beta limits are avoided, and that optimal operation is achieved even when actuators reach saturation. Supported by the NSF CAREER award program (ECCS-0645086).

  9. CCSDS Spacecraft Monitor and Control Mission Operations Interoperability Prototype

    Science.gov (United States)

    Lucord, Steve; Martinez, Lindolfo

    2009-01-01

    We are entering a new era in space exploration. Reduced operating budgets require innovative solutions to leverage existing systems to implement the capabilities of future missions. Custom solutions to fulfill mission objectives are no longer viable. Can NASA adopt international standards to reduce costs and increase interoperability with other space agencies? Can legacy systems be leveraged in a service oriented architecture (SOA) to further reduce operations costs? The Operations Technology Facility (OTF) at the Johnson Space Center (JSC) is collaborating with Deutsches Zentrum fur Luft- und Raumfahrt (DLR) to answer these very questions. The Mission Operations and Information Management Services Area (MOIMS) Spacecraft Monitor and Control (SM&C) Working Group within the Consultative Committee for Space Data Systems (CCSDS) is developing the Mission Operations standards to address this problem space. The set of proposed standards presents a service oriented architecture to increase the level of interoperability among space agencies. The OTF and DLR are developing independent implementations of the standards as part of an interoperability prototype. This prototype will address three key components: validation of the SM&C Mission Operations protocol, exploration of the Object Management Group (OMG) Data Distribution Service (DDS), and the incorporation of legacy systems in a SOA. The OTF will implement the service providers described in the SM&C Mission Operation standards to create a portal for interaction with a spacecraft simulator. DLR will implement the service consumers to perform the monitor and control of the spacecraft. The specifications insulate the applications from the underlying transport layer. We will gain experience with a DDS transport layer as we delegate responsibility to the middleware and explore transport bridges to connect disparate middleware products. A SOA facilitates the reuse of software components. The prototype will leverage the

  10. Computing an operating parameter of a unified power flow controller

    Science.gov (United States)

    Wilson, David G; Robinett, III, Rush D

    2015-01-06

    A Unified Power Flow Controller described herein comprises a sensor that outputs at least one sensed condition, a processor that receives the at least one sensed condition, a memory that comprises control logic that is executable by the processor; and power electronics that comprise power storage, wherein the processor causes the power electronics to selectively cause the power storage to act as one of a power generator or a load based at least in part upon the at least one sensed condition output by the sensor and the control logic, and wherein at least one operating parameter of the power electronics is designed to facilitate maximal transmittal of electrical power generated at a variable power generation system to a grid system while meeting power constraints set forth by the electrical power grid.

  11. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  12. Contactless operating table control based on 3D image processing.

    Science.gov (United States)

    Schröder, Stephan; Loftfield, Nina; Langmann, Benjamin; Frank, Klaus; Reithmeier, Eduard

    2014-01-01

    Interaction with mobile consumer devices leads to a higher acceptance and affinity of persons to natural user interfaces and perceptional interaction possibilities. New interaction modalities become accessible and are capable to improve human machine interaction even in complex and high risk environments, like the operation room. Here, manifold medical disciplines cause a great variety of procedures and thus staff and equipment. One universal challenge is to meet the sterility requirements, for which common contact-afflicted remote interfaces always pose a potential risk causing a hazard for the process. The proposed operating table control system overcomes this process risk and thus improves the system usability significantly. The 3D sensor system, the Microsoft Kinect, captures the motion of the user, allowing a touchless manipulation of an operating table. Three gestures enable the user to select, activate and manipulate all segments of the motorised system in a safe and intuitive way. The gesture dynamics are synchronised with the table movement. In a usability study, 15 participants evaluated the system with a system usability score by Broke of 79. This states a high potential for implementation and acceptance in interventional environments. In the near future, even processes with higher risks could be controlled with the proposed interface, while interfaces become safer and more direct.

  13. Ground Operations Autonomous Control and Integrated Health Management

    Science.gov (United States)

    Daniels, James

    2014-01-01

    The Ground Operations Autonomous Control and Integrated Health Management plays a key role for future ground operations at NASA. The software that is integrated into this system is called G2 2011 Gensym. The purpose of this report is to describe the Ground Operations Autonomous Control and Integrated Health Management with the use of the G2 Gensym software and the G2 NASA toolkit for Integrated System Health Management (ISHM) which is a Computer Software Configuration Item (CSCI). The decision rationale for the use of the G2 platform is to develop a modular capability for ISHM and AC. Toolkit modules include knowledge bases that are generic and can be applied in any application domain module. That way, there's a maximization of reusability, maintainability, and systematic evolution, portability, and scalability. Engine modules are generic, while application modules represent the domain model of a specific application. Furthermore, the NASA toolkit, developed since 2006 (a set of modules), makes it possible to create application domain models quickly, using pre-defined objects that include sensors and components libraries for typical fluid, electrical, and mechanical systems.

  14. Robust Fault-Tolerant Control for Satellite Attitude Stabilization Based on Active Disturbance Rejection Approach with Artificial Bee Colony Algorithm

    OpenAIRE

    Fei Song; Shiyin Qin

    2014-01-01

    This paper proposed a robust fault-tolerant control algorithm for satellite stabilization based on active disturbance rejection approach with artificial bee colony algorithm. The actuating mechanism of attitude control system consists of three working reaction flywheels and one spare reaction flywheel. The speed measurement of reaction flywheel is adopted for fault detection. If any reaction flywheel fault is detected, the corresponding fault flywheel is isolated and the spare reaction flywhe...

  15. Mission Operations Control Room Activities during STS-2 mission

    Science.gov (United States)

    1981-01-01

    Mission Operations Control Room (MOCR) activities during STS-2 mission. Overall view of the MOCR in the Johnson Space Center's Mission Control Center. At far right is Eugene F. Kranz, Deputy Director of Flight Operations. At the flight director console in front of Kranz's FOD console are Flight Directors M.P. Frank, Neil B. Hutchinson and Donald R. Puddy as well as others (39506); Wide-angle view of flight controllers in the MOCR. Clifford E. Charlesworth, JSC Deputy Director, huddles with several flight directors for STS-2 at the flight director console. Kranz, is at far right of frame (39507); Dr. Christopher C. Kraft, Jr., JSC Director, center, celebrates successful flight and landing of STS-2 with a cigar in the MOCR. He is flanked by Dr. Maxime A Faget, left, Director of Engineering and Development, and Thomas L. Moser, of the Structures and Mechanics Division (39508); Flight Director Donald R. Puddy, near right, holds replica of the STS-2 insignia. Insignias on the opposite wall

  16. A practical small satellite variable-speed control moment gyroscope for combined energy storage and attitude control

    Science.gov (United States)

    Richie, David J.; Lappas, Vaios J.; Prassinos, George

    2009-12-01

    A recent effort to develop single-gimbal variable-speed control moment gyroscopes (VSCMGs) for a combined energy storage and attitude control subsystem (ESACS) on small satellites has culminated in laboratory validation of the concept. A single actuator prototype comprised of a cutting-edge Carbon Fiber rotor and COTS motor/generator components has been developed, balanced, bench tested, and integrated onto a spherical air-bearing structure. This structure is used to demonstrate the primary capability of a VSCMG to act as a dynamo whilst simultaneously changing a spacecraft's orientation in a controlled fashion. As originally predicted, the actuator's flywheel spins up when energy is supplied (supported via a direct energy transfer power architecture), then spins down when the energy source is removed, porting the energy released to run a resistive load. The work presented gives an overview of the governing principles of the technology, addresses the underlying mission and design requirements, and presents the prototype design. Then, effectiveness of the prototype integrated on a three-axis test article is presented along with its associated test data. Finally, discussion of these results and identification of future research concludes the work. The benefits of this technology for future space missions are that system consolidation permits mass reduction, higher instantaneous peak power is available as compared to conventional secondary battery systems, state-of-charge measurement is readily available from wheel speed feedback, and torque amplification through gimballing permits efficient actuator control. The technology demonstrated is exciting and leaves the door open for future development via inclusion of magnetic levitation.

  17. Analysing the Advantages of High Temporal Resolution Geostationary MSG SEVIRI Data Compared to Polar Operational Environmental Satellite Data for Land Surface Monitoring in Africa

    Science.gov (United States)

    Fensholt, R.; Anyamba, A.; Huber, S.; Proud, S. R.; Tucker, C. J.; Small, J.; Pak, E.; Rasmussen, M. O.; Sandholt, I.; Shisanya, C.

    2011-01-01

    Since 1972, satellite remote sensing of the environment has been dominated by polar-orbiting sensors providing useful data for monitoring the earth s natural resources. However their observation and monitoring capacity are inhibited by daily to monthly looks for any given ground surface which often is obscured by frequent and persistent cloud cover creating large gaps in time series measurements. The launch of the Meteosat Second Generation (MSG) satellite into geostationary orbit has opened new opportunities for land surface monitoring. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument on-board MSG with an imaging capability every 15 minutes which is substantially greater than any temporal resolution that can be obtained from existing polar operational environmental satellites (POES) systems currently in use for environmental monitoring. Different areas of the African continent were affected by droughts and floods in 2008 caused by periods of abnormally low and high rainfall, respectively. Based on the effectiveness of monitoring these events from Earth Observation (EO) data the current analyses show that the new generation of geostationary remote sensing data can provide higher temporal resolution cloud-free (less than 5 days) measurements of the environment as compared to existing POES systems. SEVIRI MSG 5-day continental scale composites will enable rapid assessment of environmental conditions and improved early warning of disasters for the African continent such as flooding or droughts. The high temporal resolution geostationary data will complement existing higher spatial resolution polar-orbiting satellite data for various dynamic environmental and natural resource applications of terrestrial ecosystems.

  18. Normal Form Bisimulations for Delimited-Control Operators

    CERN Document Server

    Biernacki, Dariusz

    2012-01-01

    We define a notion of normal form bisimilarity for the untyped call-by-value lambda calculus extended with the delimited-control operators shift and reset. Normal form bisimilarities are simple, easy-to-use behavioral equivalences which relate terms without having to test them within all contexts (like contextual equivalence), or by applying them to function arguments (like applicative bisimilarity). We prove that the normal form bisimilarity for shift and reset is sound but not complete w.r.t. contextual equivalence and we define up-to techniques that aim at simplifying bisimulation proofs. Finally, we illustrate the simplicity of the techniques we develop by proving several equivalences on terms.

  19. Using Robotic Operating System (ROS) to control autonomous observatories

    Science.gov (United States)

    Vilardell, Francesc; Artigues, Gabriel; Sanz, Josep; García-Piquer, Álvaro; Colomé, Josep; Ribas, Ignasi

    2016-07-01

    Astronomical observatories are complex systems requiring the integration of numerous devices into a common platform. We are presenting here the firsts steps to integrate the popular Robotic Operating System (ROS) into the control of a fully autonomous observatory. The observatory is also equipped with a decision-making procedure that can automatically react to a changing environment (like weather events). The results obtained so far have shown that the automation of a small observatory can be greatly simplified when using ROS, as well as robust, with the implementation of our decision-making algorithms.

  20. Implementing controlled-unitary operations over the butterfly network

    Science.gov (United States)

    Soeda, Akihito; Kinjo, Yoshiyuki; Turner, Peter S.; Murao, Mio

    2014-12-01

    We introduce a multiparty quantum computation task over a network in a situation where the capacities of both the quantum and classical communication channels of the network are limited and a bottleneck occurs. Using a resource setting introduced by Hayashi [1], we present an efficient protocol for performing controlled-unitary operations between two input nodes and two output nodes over the butterfly network, one of the most fundamental networks exhibiting the bottleneck problem. This result opens the possibility of developing a theory of quantum network coding for multiparty quantum computation, whereas the conventional network coding only treats multiparty quantum communication.