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Sample records for autonomous star tracker

  1. Autonomous Star Tracker Algorithms

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Kilsgaard, Søren;

    1998-01-01

    Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances.......Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances....

  2. CLOSED LOOP AOCS TESTING OF AN AUTONOMOUS STAR TRACKER

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    . It is a fully autonomous star tracker intended as a high accuracy attitude reference onboard spacecrafts. The ASC consists of a miniaturized but powerful microcomputer driving from one to four CCD-based camera heads. The use of multiple camera heads may relieve several constraints on the AOCS, such as increased...

  3. Miniature Autonomous Star Tracker Based on CMOS APS

    OpenAIRE

    Ying, Dong; Zheng, You; Fei, Xing; Qin, Chou

    2006-01-01

    An APS (Active Pixel Sensor) based autonomous star tracker (AAST) has been proposed for small satellite and microsatellite attitude determination. A prototype of AAST has been developed. It has low mass of 1kg, low power of 3W, high rate up to 5Hz, and acquisition success rate of higher than 99.9%. The improvements in dimensions and performances are realized with the replacement of the CCD (Charge Coupled Device) by the APS. The optical design of the prototype is based on PSF (Point Spread Fu...

  4. On-Orbit Performance of Autonomous Star Trackers

    Science.gov (United States)

    Airapetian, V.; Sedlak, J.; Hashmall, J.

    2001-01-01

    This paper presents the results of a performance study of the autonomous star trackers (ASTs) on the IMAGE and the EO-1 spacecraft. IMAGE is a spinning spacecraft without gyros or redundant precision attitude sensors, so the statistical properties of the AST are estimated simply by comparing the output observed quaternions with a rigid rotator model with constant angular momentum. The initial conditions are determined by a least-squares fit to minimize the AST residuals. An additional fit is used to remove the remaining systematic error and to obtain the inherent sensor noise. Gyro rate data are available for the EO-1 mission, so the AST noise statistics are obtained from the residuals after solving for an epoch attitude and gyro bias also using a least-squares method.

  5. Operational Experience with Autonomous Star Trackers on ESA Interplanetary Spacecraft

    Science.gov (United States)

    Lauer, Mathias; Jauregui, Libe; Kielbassa, Sabine

    2007-01-01

    Mars Express (MEX), Rosetta and Venus Express (VEX) are ESA interplanetary spacecrafts (S/C) launched in June 2003, March 2004 and November 2005, respectively. Mars Express was injected into Mars orbit end of 2003 with routine operations starting in spring 2004. Rosetta is since launch on its way to rendezvous comet Churyumov-Gerasimenko in 2014. It has completed several test and commissioning activities and is performing several planetary swingbys (Earth in spring 2005, Mars in spring 2007, Earth in autumn 2007 and again two years later). Venus Express has also started routine operations since the completion of the Venus orbit insertion maneuver sequence beginning of May 2006. All three S/C are three axes stabilized with a similar attitude and orbit control system (AOCS). The attitude is estimated on board using star and rate sensors and controlled using four reaction wheels. A bipropellant reaction control system with 10N thrusters serves for wheel off loadings and attitude control in safe mode. Mars Express and Venus Express have an additional 400N engine for the planetary orbit insertion. Nominal Earth communication is accomplished through a high gain antenna. All three S/C are equipped with a redundant set of autonomous star trackers (STR) which are based on almost the same hardware. The STR software is especially adapted for the respective mission. This paper addresses several topics related to the experience gained with the STR operations on board the three S/C so far.

  6. CLOSED LOOP AOCS TESTING OF AN AUTONOMOUS STAR TRACKER

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    The only really efficient way of evading the above dilemma is, to build in AIT support functionality into the autonomous unit. This paper discusses the AIT support functions of a highly autonomous instrument, the Advanced Stellar Compass (ASC), developed by the department of Automation at DTU. It...... not even a high quality star pattern generator may be able to pass the outlier rejection filtering of the ASC thus efficiently precluding artificial stimuli during AIT tests. In order to circumvent this impasse, the ASC has a series of build-in features enabling simple, yet comprehensive, closed loop...... testing. These features encompass a suite of support functions including an in-line attitude simulator, image up and download features, and failure and surveillance monitors. The paper describes the operation of these modes and how they have been used during the AIT of several spacecrafts....

  7. The MONS Star Trackers

    CERN Document Server

    Bedding, T R; Bedding, Timothy R.; Kjeldsen, Hans

    2000-01-01

    The MONS satellite will have two Star Trackers to sense the spacecraft attitude, and we plan to use them as scientific instruments to perform high-precision photometry of thousands of stars. We briefly describe the current plans for the Star Trackers and their expected capabilities.

  8. Intelligent Star Tracker

    OpenAIRE

    Clark, Natalie; Furth, Paul; Horan, Steven

    2000-01-01

    We describe our Intelligent Star Tracker System. Our Intelligent Star Tracker System incorporates an adaptive optic catadioptric telescope in a silicon carbide housing. Leveraging off of our active optic technologies, the novel active pixel position sensors (APPS) enable wide dynamic range and allows simultaneous imagery of faint and bright stars in a single image. Moreover, the APPS, in conjunction with the adaptive optics technologies, offer unprecedented accuracy in altitude and navigation...

  9. Interferometric star tracker Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optical Physics Company (OPC) proposes to develop a high accuracy version of its interferometric star tracker capable of meeting the milli-arcsecond-level pointing...

  10. Vidicon star tracker.

    Science.gov (United States)

    Schuck, W H

    1966-04-01

    In many applications of star trackers, extremely short acquisition times, as well as accuracy and sensitivity, are required. Tracking systems employing the vidicon as a radiation sensor have been shown to provide the necessary speed of acquisition for such applications. This paper discusses the various theoretical and practical considerations involved in using the vidicon as a sensor in a star tracking system. A typical system configuration including telescope, sensor, and processing electronics is presented. The various optical and sensor parametric relationships required in the design of a vidicon star tracker are fully discussed and analyzed. PMID:20048884

  11. Star trackers for attitude determination

    DEFF Research Database (Denmark)

    Liebe, Carl Christian

    1995-01-01

    CCD camera and a powerful microcomputer. The instruments are called star trackers and they are capable of determining the attitude with an accuracy better than 1 arcsecond. The concept of the star tracker is explained. The obtainable accuracy is calculated, the numbers of stars to be included in the...... star catalogue are discussed and the acquisition of the initial attitude is explained. Finally the commercial market for star trackers is discussed...

  12. STAR Integrated Tracker

    CERN Document Server

    Rose, A

    2003-01-01

    We present the design and performance analysis of a new integrated track reconstruction code developed for the STAR experiment at RHIC. The code is meant to replace multiple previous tracking codes written in FORTRAN many years ago, and to readily enable the integration of new and varied detector components. The new tracker is written from the ground up in C++ using a strong object-oriented model. Key features include an abstract geometry model for representation of detector components, a flexible track representation model, a built-in KALMAN filter for track parameter determination, and a powerful object factory model for fast handling of numerous small objects, such as hits and tracks. The new tracker will be deployed and used for analysis of data aquired during the RHIC year 3 run of the STAR experiment.

  13. STAR Integrated Tracker

    OpenAIRE

    Rose, A.

    2003-01-01

    We present the design and performance analysis of a new integrated track reconstruction code developed for the STAR experiment at RHIC. The code is meant to replace multiple previous tracking codes written in FORTRAN many years ago, and to readily enable the integration of new and varied detector components. The new tracker is written from the ground up in C++ using a strong object-oriented model. Key features include an abstract geometry model for representation of detector components, a fle...

  14. STAR heavy flavor tracker

    International Nuclear Information System (INIS)

    Hadrons containing heavy quarks are a clean probe of the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. To explore heavy quark production at RHIC, the Heavy Flavor Tracker (HFT) for the STAR experiment was built and installed in time for RHIC Run 14. The HFT consists of four layers of silicon detectors. The two outermost layers are silicon strip detectors and the two innermost layers are made from state-of-the-art ultra-thin CMOS Monolithic Active Pixel Sensors (MAPS). This is the first application of a CMOS MAPS detector in a collider experiment. The use of thin pixel sensors plus the use of carbon fiber supporting material limits the material budget to be only 0.4% radiation length per pixel detector layer, enabling the reconstruction of low pT heavy flavor hadrons. The status and performance of the HFT in the RHIC 200 GeV Au + Au run in 2014 are reported. Very good detector efficiency, hit residuals and track resolution (DCAs) were observed in the cosmic ray data and in the Au + Au data

  15. STAR heavy flavor tracker

    Science.gov (United States)

    Qiu, Hao

    2014-11-01

    Hadrons containing heavy quarks are a clean probe of the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. To explore heavy quark production at RHIC, the Heavy Flavor Tracker (HFT) for the STAR experiment was built and installed in time for RHIC Run 14. The HFT consists of four layers of silicon detectors. The two outermost layers are silicon strip detectors and the two innermost layers are made from state-of-the-art ultra-thin CMOS Monolithic Active Pixel Sensors (MAPS). This is the first application of a CMOS MAPS detector in a collider experiment. The use of thin pixel sensors plus the use of carbon fiber supporting material limits the material budget to be only 0.4% radiation length per pixel detector layer, enabling the reconstruction of low pT heavy flavor hadrons. The status and performance of the HFT in the RHIC 200 GeV Au + Au run in 2014 are reported. Very good detector efficiency, hit residuals and track resolution (DCAs) were observed in the cosmic ray data and in the Au + Au data.

  16. STAR heavy flavor tracker

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Hao

    2014-11-15

    Hadrons containing heavy quarks are a clean probe of the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. To explore heavy quark production at RHIC, the Heavy Flavor Tracker (HFT) for the STAR experiment was built and installed in time for RHIC Run 14. The HFT consists of four layers of silicon detectors. The two outermost layers are silicon strip detectors and the two innermost layers are made from state-of-the-art ultra-thin CMOS Monolithic Active Pixel Sensors (MAPS). This is the first application of a CMOS MAPS detector in a collider experiment. The use of thin pixel sensors plus the use of carbon fiber supporting material limits the material budget to be only 0.4% radiation length per pixel detector layer, enabling the reconstruction of low p{sub T} heavy flavor hadrons. The status and performance of the HFT in the RHIC 200 GeV Au + Au run in 2014 are reported. Very good detector efficiency, hit residuals and track resolution (DCAs) were observed in the cosmic ray data and in the Au + Au data.

  17. Advanced Exoplanet Star Tracker for Orbit Self Determination Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal puts forth an innovative star tracker hardware sensor that allows for autonomous calculation of a spacecraft's orbit by employing Doppler Spectroscopy...

  18. Focal Adjustment for Star Tracker

    OpenAIRE

    Liu Hai-bo; Jian-kun Yang; Ji-chun Tan; De-zhi Su; Wen-liang Wang; Xiu-jian Li; Hui Jia

    2010-01-01

    Technique of measuring intensity distribution and size of spot image developed has been discussed, which is especially suitable for defocus adjustment in ground test of star tracker. A novel approach for choosing a proper defocusing position has been proposed based on collimator, Gaussian surface fitting method, and other ordinary instruments. It proves to be practical and adequate in the development of distant object tracking such as star tracker.Defence Science Journal, 2010, 60(6), pp.678-...

  19. Space Shuttle Star Tracker Challenges

    Science.gov (United States)

    Herrera, Linda M.

    2010-01-01

    The space shuttle fleet of avionics was originally designed in the 1970's. Many of the subsystems have been upgraded and replaced, however some original hardware continues to fly. Not only fly, but has proven to be the best design available to perform its designated task. The shuttle star tracker system is currently flying as a mixture of old and new designs, each with a unique purpose to fill for the mission. Orbiter missions have tackled many varied missions in space over the years. As the orbiters began flying to the International Space Station (ISS), new challenges were discovered and overcome as new trusses and modules were added. For the star tracker subsystem, the growing ISS posed an unusual problem, bright light. With two star trackers on board, the 1970's vintage image dissector tube (IDT) star trackers track the ISS, while the new solid state design is used for dim star tracking. This presentation focuses on the challenges and solutions used to ensure star trackers can complete the shuttle missions successfully. Topics include KSC team and industry partner methods used to correct pressurized case failures and track system performance.

  20. Focal Adjustment for Star Tracker

    Directory of Open Access Journals (Sweden)

    Liu Hai-bo

    2010-10-01

    Full Text Available Technique of measuring intensity distribution and size of spot image developed has been discussed, which is especially suitable for defocus adjustment in ground test of star tracker. A novel approach for choosing a proper defocusing position has been proposed based on collimator, Gaussian surface fitting method, and other ordinary instruments. It proves to be practical and adequate in the development of distant object tracking such as star tracker.Defence Science Journal, 2010, 60(6, pp.678-682, DOI:http://dx.doi.org/10.14429/dsj.60.36

  1. Optical filtering for star trackers

    Science.gov (United States)

    Wilson, R. E.

    1973-01-01

    The optimization of optical filtering was investigated for tracking faint stars, down to the fifth magnitude. The effective wavelength and bandwidth for tracking pre-selected guide stars are discussed along with the results of an all-electronic tracker with a star tracking photomultiplier, which was tested with a simulated second magnitude star. Tables which give the sum of zodiacal light and galactic background light over the entire sky for intervals of five degrees in declination, and twenty minutes in right ascension are included.

  2. Star trackers for attitude determination

    OpenAIRE

    Liebe, Carl Christian

    1995-01-01

    One problem comes to all spacecrafts using vector information. That is the problem of determining the attitude. This paper describes how the area of attitude determination instruments has evolved from simple pointing devices into the latest technology, which determines the attitude by utilizing a CCD camera and a powerful microcomputer. The instruments are called star trackers and they are capable of determining the attitude with an accuracy better than 1 arcsecond. The concept of the star tr...

  3. Towards Star Tracker Only Attitude Estimation

    OpenAIRE

    Enright, John; Sinclair, Doug; Grant, Cordell; McVittie, Geoff; Dzamba, Tom

    2010-01-01

    Star trackers can provide full information about satellite attitude information from a single sensor. In this paper, we examine the feasibility of designing attitude determination systems using only star trackers. Star trackers can provide direct inertial attitude estimates without the need for sensor fusion, but current sensors are not robust enough to provide effective attitude estimates in all mission scenarios. Specific technical capabilities must be developed before star tracker only sch...

  4. Performance of the Microwave Anisotropy Probe AST-201 Star Trackers

    Science.gov (United States)

    Ward, David K.; vanBezooijen, Roelof; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) was launched to create a full-sky map of the cosmic microwave background. MAP incorporates two modified Lockheed Martin AST-201 (Autonomous Star Tracker) star trackers. The AST-201 employs an eight element radiation hardened lens assembly which is used to focus an image on a charge coupled device (CCD). The CCD image is then processed by a star identification algorithm which outputs a three-axis attitude. A CCD-shift algorithm called Time Delayed Integration (TDI) was also included in each star tracker. In order to provide some radiation effect filtering during MAP's three to five phasing loop passes through the Van Allen radiation belts, a simple pixel filtering scheme was implemented, rather than using a more complex, but more robust windowing algorithm. The trackers also include a fiber optic data interface. This paper details the ground testing that was accomplished on the MAP trackers.

  5. The STAR Forward GEM Tracker

    Science.gov (United States)

    Balewski, Jan

    2008-10-01

    The STAR collaboration is preparing a tracking detector upgrade, the Heavy Flavor Tracker (HFT) [1] and the Forward GEM Tracker (FGT) to further investigate fundamental properties of the new state of strongly interacting matter produced in relativistic-heavy ion collisions at RHIC and to provide fundamental studies of the proton spin structure and dynamics in high-energy polarized proton-proton collisions at RHIC. The FGT will focus on novel spin physics measurements in high-energy polarized proton-proton collisions, determining the flavor dependence (δu versus δd) of the polarized sea. STAR plans to probe these PDFs using parity violating W production and decay. W^-(+) bosons are produced in u+d,d+u) collisions and can be detected through their leptonic decays, e^-+νe,e^++νe), where only the respective charged lepton is measured. The sensitivity of those measurements is enhanced in the forward direction. The discrimination of u+d (d+u) quark combinations requires distinguishing between high pT e^-(+) through their opposite charge sign. An upgrade of the STAR forward tracking system is needed to provide the required tracking precision for charge sign discrimination. This upgrade will consist of six triple-GEM detectors with two dimensional readout arranged in disks along the beam axis. The FGT design and installation schedule will be presented. [1] The STAR Heavy-Flavor Tracker, DNP Fall 2008 Meeting.

  6. Star-Tracker Computer Program

    Science.gov (United States)

    Glavich, Thomas

    1987-01-01

    Image-analyzing pointing systems aimed to high precision. Star-tracker program, STRACKER, developed to solve algorithm-design problems for area-array tracking and pointing systems operating at accuracies of 0.001 to 0.01 picture element. Includes auxiliary programs for reformatting point-spread data from commercial ACCOSV lens-design program. Other optical-analysis program data reformatted by use of utility routines included in package. Written in FORTRAN 77.

  7. Development and Implementation of Star Tracker Electronics

    OpenAIRE

    Lindh, Marcus

    2014-01-01

    Star trackers are essential instruments commonly used on satellites. They provide precise measurement of the orientation of a satellite and are part of the attitude control system. For cubesats star trackers need to be small, consume low power and preferably cheap to manufacture. In this thesis work the electronics for a miniature star tracker has been developed. A star detection algorithm has been implemented in hardware logic, tested and verified. A platform for continued work is presented ...

  8. Precession–nutation correction for star tracker attitude measurement of STECE satellite

    OpenAIRE

    Lai Yuwang; Liu Junhong; Ding Yonghe; Gu Defeng; Yi Dongyun

    2014-01-01

    Space Technology Experiment and Climate Exploration (STECE) is a small satellite mission of China for space technology experiment and climate exploration. A new test star tracker and one ASTRO 10 star tracker have been loaded on the STECE satellite to test the new star tracker’s measurement performance. However, there is no autonomous precession–nutation correction function for the test star tracker, which causes an apparent periodic deflection in the inter-boresight angle between the two sta...

  9. Star Position Estimation Improvements for Accurate Star Tracker Attitude Estimation

    OpenAIRE

    Delabie, Tjorven

    2015-01-01

    This paper presents several methods to improve the estimation of the star positions in a star tracker, using a Kalman Filter. The accuracy with which the star positions can be estimated greatly influences the accuracy of the star tracker attitude estimate. In this paper, a Kalman Filter with low computational complexity, that can be used to estimate the star positions based on star tracker centroiding data and gyroscope data is discussed. The performance of this Kalman Filter can be increased...

  10. Star tracker for the Apollo telescope mount

    Science.gov (United States)

    Lee, C. E.

    1971-01-01

    The star tracker for the Apollo Telescope Mount (ATM) has been designed specifically to meet the requirements of the Skylab vehicle and mission. The functions of the star tracker are presented, as well as descriptions of the optical-mechanical assembly (OMA) and the star tracker electronics (STE). Also included are the electronic and mechanical specifications, interface and operational requirements, support equipment and test requirements, and occultation information. Laboratory functional tests, environmental qualification tests, and life tests have provided a high confidence factor in the performance of the star tracker in the laboratory and on the Skylab mission.

  11. Rosetta Star Tracker and Navigation Camera

    DEFF Research Database (Denmark)

    Thuesen, Gøsta

    1998-01-01

    Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera.......Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera....

  12. The STAR Heavy Flavor Tracker

    Science.gov (United States)

    Videbaek, Flemming; STAR Collaboration

    2013-10-01

    The Heavy Flavor Tracker (HFT) is an on-going upgrade for the STAR detector at RHIC that aim to study heavy quark production. In relativistic heavy-ion collisions at RHIC, heavy quarks are primarily created from initial hard scatterings. Since their large masses are not easily affected by the strong interaction with QCD medium they may carry information from the system at early stage. The interaction between heavy quarks and the medium is sensitive to the medium dynamics; therefore heavy quarks are suggested as an ideal probe to quantify the properties of the strongly interacting QCD matter. The HFT detectors will study this via the topological reconstruction of open charm hadrons. The HFT that consists of a thin two layer inner Pixel vertex detector, and two outer concentric layers of silicon, the Silicon Strip Detector, and the Intermediate Silicon Tracker. We will show how this detector system can assess heavy flavor physics with great precision. An overview of the HFT that will be completed for the upcoming RHIC run-14, its expected performance, and current status will be presented. Supported by the Division of Nuclear Physics of the Office of Science of the U.S. Department of Energy.

  13. The STAR Heavy Flavour Tracker

    International Nuclear Information System (INIS)

    In order to understand the partonic EOS of matter created at RHIC, one needs to study both the collectivity of the produced matter and the degree of thermalization. We propose to address this physics through the study of heavy flavour hadrons in high-energy nuclear collisions at RHIC. The heavy flavour tracker (HFT), a tracking upgrade of the STAR experiment, is being designed to provide an unambiguous measurement of charm hadrons through the direct reconstruction of hadronic decays. These measurements require high accuracy space points near the collision vertex. The current design of our detector uses a novel CMOS-based sensor, allowing for a low-mass and high-resolution detector element. We provide rate estimations for D0 v2 measurements in Au+Au collisions at 200 GeV

  14. A Heavy Flavor Tracker for STAR

    International Nuclear Information System (INIS)

    We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era

  15. A Heavy Flavor Tracker for STAR

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Miller,M.; Surrow, B.; Van Nieuwenhuizen G.; Bieser, F.; Gareus, R.; Greiner,L.; Lesser, F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for theSTAR experiment at RHIC. The HFT will bring new physics capabilities toSTAR and it will significantly enhance the physics capabilities of theSTAR detector at central rapidities. The HFT will ensure that STAR willbe able to take heavy flavor data at all luminosities attainablethroughout the proposed RHIC II era.

  16. A Heavy Flavor Tracker for STAR

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Surrow,B.; Van Nieuwenhuizen, G.; Bieser, F.; Gareus, R.; Greiner, L.; Lesser,F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era.

  17. A Heavy Flavor Tracker for STAR

    OpenAIRE

    Z. Xu; Chen, Y; Kleinfelder, S.; Koohi, A.; Li, S.; H. Huang; Tai, A.; Kushpil, V.; Sumbera, M; Colledani, C.; Dulinski, W.; Himmi, A.; Hu, C; Shabetai, A.; Szelezniak, M.

    2005-01-01

    We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era.

  18. Opportunity Science Using the Juno Magnetometer Investigation Star Trackers

    Science.gov (United States)

    Joergensen, J. L.; Connerney, J. E.; Bang, A. M.; Denver, T.; Oliversen, R. J.; Benn, M.; Lawton, P.

    2013-12-01

    The magnetometer experiment onboard Juno is equipped with four non-magnetic star tracker camera heads, two of which reside on each of the magnetometer sensor optical benches. These are located 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. The star tracker, collectively referred to as the Advanced Stellar Compass (ASC), provides high accuracy attitude information for the magnetometer sensors throughout science operations. The star tracker camera heads are pointed +/- 13 deg off the spin vector, in the anti-sun direction, imaging a 13 x 20 deg field of view every ¼ second as Juno rotates at 1 or 2 rpm. The ASC is a fully autonomous star tracker, producing a time series of attitude quaternions for each camera head, utilizing a suite of internal support functions. These include imaging capabilities, autonomous object tracking, automatic dark-sky monitoring, and related capabilities; these internal functions may be accessed via telecommand. During Juno's cruise phase, this capability can be tapped to provide unique science and engineering data available along the Juno trajectory. We present a few examples of the JUNO ASC opportunity science here. As the Juno spacecraft approached the Earth-Moon system for the close encounter with the Earth on October 9, 2013, one of the ASC camera heads obtained imagery of the Earth-Moon system while the other three remained in full science (attitude determination) operation. This enabled the first movie of the Earth and Moon obtained by a spacecraft flying past the Earth in gravity assist. We also use the many artificial satellites in orbit about the Earth as calibration targets for the autonomous asteroid detection system inherent to the ASC autonomous star tracker. We shall also profile the zodiacal dust disk, using the interstellar image data, and present the outlook for small asteroid body detection and distribution being performed during Juno's passage from Earth flyby to Jovian orbit

  19. A microprocessor-controlled CCD star tracker

    Science.gov (United States)

    Salomon, P. M.; Goss, W. C.

    1976-01-01

    The STELLAR (Star Tracker for Economical Long Life Attitude Reference) utilizes an image sensing Charge-Coupled Device (CCD) operating under microprocessor control. This approach results in a new type of high-accuracy star tracker which can be adapted to a wide variety of different space flight applications through software changes only. The STELLAR determines two-axis star positions by computing the element and the interelement interpolated centroid positions of the star images. As many as 10 stars may be tracked simultaneously, providing significantly increased stability and accuracy. A detailed description of the STELLAR is presented along with measurements of system performance obtained from an operating breadboard model.

  20. Combinations of 148 navigation stars and the star tracker

    Science.gov (United States)

    Duncan, R.

    1980-01-01

    The angular separation of all star combinations for 148 nav star on the onboard software for space transportation system-3 flight and following missions is presented as well as the separation of each pair that satisfies the viewing constraints of using both star trackers simultaneously. Tables show (1) shuttle star catalog 1980 star position in M 1950 coordinates; (2) two star combination of 148 nav stars; and (3) summary of two star-combinations of the star tracker 5 deg filter. These 148 stars present 10,875 combinations. For the star tracker filters of plus or minus 5 deg, there are 875 combinations. Formalhaut (nav star 26) has the best number of combinations, which is 33.

  1. Star Tracker Performance Estimate with IMU

    Science.gov (United States)

    Aretskin-Hariton, Eliot D.; Swank, Aaron J.

    2015-01-01

    A software tool for estimating cross-boresight error of a star tracker combined with an inertial measurement unit (IMU) was developed to support trade studies for the Integrated Radio and Optical Communication project (iROC) at the National Aeronautics and Space Administration Glenn Research Center. Typical laser communication systems, such as the Lunar Laser Communication Demonstration (LLCD) and the Laser Communication Relay Demonstration (LCRD), use a beacon to locate ground stations. iROC is investigating the use of beaconless precision laser pointing to enable laser communication at Mars orbits and beyond. Precision attitude knowledge is essential to the iROC mission to enable high-speed steering of the optical link. The preliminary concept to achieve this precision attitude knowledge is to use star trackers combined with an IMU. The Star Tracker Accuracy (STAcc) software was developed to rapidly assess the capabilities of star tracker and IMU configurations. STAcc determines the overall cross-boresight error of a star tracker with an IMU given the characteristic parameters: quantum efficiency, aperture, apparent star magnitude, exposure time, field of view, photon spread, detector pixels, spacecraft slew rate, maximum stars used for quaternion estimation, and IMU angular random walk. This paper discusses the supporting theory used to construct STAcc, verification of the program and sample results.

  2. Star spot location estimation using Kalman filter for star tracker.

    Science.gov (United States)

    Liu, Hai-bo; Yang, Jian-kun; Wang, Jiong-qi; Tan, Ji-chun; Li, Xiu-jian

    2011-04-20

    Star pattern recognition and attitude determination accuracy is highly dependent on star spot location accuracy for the star tracker. A star spot location estimation approach with the Kalman filter for a star tracker has been proposed, which consists of three steps. In the proposed approach, the approximate locations of the star spots in successive frames are predicted first; then the measurement star spot locations are achieved by defining a series of small windows around each predictive star spot location. Finally, the star spot locations are updated by the designed Kalman filter. To confirm the proposed star spot location estimation approach, the simulations based on the orbit data of the CHAMP satellite and the real guide star catalog are performed. The simulation results indicate that the proposed approach can filter out noises from the measurements remarkably if the sampling frequency is sufficient. PMID:21509065

  3. Optical contacting for gravity probe star tracker

    Science.gov (United States)

    Wright, J. J.; Zissa, D. E.

    1984-01-01

    A star-tracker telescope, constructed entirely of fused silica elements optically contacted together, has been proposed to provide submilliarc-second pointing accuracy for Gravity Probe. A bibliography and discussion on optical contacting (the bonding of very flat, highly polished surfaces without the use of adhesives) are presented. Then results from preliminary experiments on the strength of optical contacts including a tensile strength test in liquid helium are discussed. Suggestions are made for further study to verify an optical contacting method for the Gravity Probe star-tracker telescope.

  4. The STAR Heavy Flavor Tracker (HFT)

    OpenAIRE

    Schambach, Joachim; Anderssen, Eric; Wieman, Howard; Woodmansee, Sam; Contin, Giacomo; Greiner, Leo; Silber, Joe; Stezelberger, Thorsten; Sun, Xiangming; Szelezniak, Michal; Videbæk, Flemming; Vu, Chinh

    2014-01-01

    The heavy quark hadrons are suggested as a clean probe for studying the early dynamic evolution of the dense and hot medium created in high-energy nuclear collisions. The Heavy Flavor Tracker (HFT) of the STAR experiment, designed to improve the vertex resolution and extend the measurement capabilities in the heavy flavor domain, was installed for the 2014 heavy ion run of RHIC. It is composed of three different silicon detectors arranged in four concentric cylinders close to the STAR interac...

  5. A Heavy Flavor Tracker for STAR

    OpenAIRE

    Chasman, C.

    2008-01-01

    The STAR Collaboration proposes to construct a state-of-the-art microvertex detector, the Heavy Flavor Tracker (HFT), utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precision measurement of the yields and spectra of particles containing heavy quarks. This will be accomplished through topological identification of D mesons by reconstruction of their displaced decay vertices with a precision of approxim...

  6. Real-Time Hardware-in-the-Loop Tests of Star Tracker Algorithms

    OpenAIRE

    Giancarlo Rufino; Domenico Accardo; Michele Grassi; Giancarmine Fasano; Alfredo Renga; Urbano Tancredi

    2013-01-01

    This paper deals with star tracker algorithms validation based on star field scene simulation and hardware-in-the-loop test configuration. A laboratory facility for indoor tests, based on the simulation of star field scenes, is presented. Attainable performance is analyzed theoretically for both static and dynamic simulations. Also, a test campaign is presented, in which a star sensor prototype with real-time, fully autonomous capability is exploited. Results that assess star field scene simu...

  7. RFP for the Auroral Multiscale Midex (AMM) Mission star tracker

    DEFF Research Database (Denmark)

    Riis, Troels; Betto, Maurizio; Jørgensen, John Leif;

    1999-01-01

    This document is in response to the John Hopkins University - Applied Physics Laboratory RFP for the Auroral Multiscale Midex Mission star tracker.It describes the functionality, the requirements and the performance of the ASC Star Tracker.......This document is in response to the John Hopkins University - Applied Physics Laboratory RFP for the Auroral Multiscale Midex Mission star tracker.It describes the functionality, the requirements and the performance of the ASC Star Tracker....

  8. Precession–nutation correction for star tracker attitude measurement of STECE satellite

    Directory of Open Access Journals (Sweden)

    Lai Yuwang

    2014-02-01

    Full Text Available Space Technology Experiment and Climate Exploration (STECE is a small satellite mission of China for space technology experiment and climate exploration. A new test star tracker and one ASTRO 10 star tracker have been loaded on the STECE satellite to test the new star tracker’s measurement performance. However, there is no autonomous precession–nutation correction function for the test star tracker, which causes an apparent periodic deflection in the inter-boresight angle between the two star trackers with respect to each other of up to ±500 arcsec, so the precession and nutation effect needs to be considered while assessing the test star tracker. This paper researches on the precession–nutation correction for the test star tracker’s attitude measurement and presents a precession–nutation correction method based on attitude quaternion data. The periodic deflection of the inter-boresight angle between the two star trackers has been greatly eliminated after the precession and nutation of the test star tracker’s attitude data have been corrected by the proposed method and the validity of the proposed algorithm has been demonstrated. The in-flight accuracy of the test star tracker has been assessed like attitude noise and low-frequency errors after the precession–nutation correction.

  9. Precession-nutation correction for star tracker attitude measurement of STECE satellite

    Institute of Scientific and Technical Information of China (English)

    Lai Yuwang; Liu Junhong; Ding Yonghe; Gu Defeng; Yi Dongyun

    2014-01-01

    Space Technology Experiment and Climate Exploration (STECE) is a small satellite mis-sion of China for space technology experiment and climate exploration. A new test star tracker and one ASTRO 10 star tracker have been loaded on the STECE satellite to test the new star tracker’s measurement performance. However, there is no autonomous precession-nutation correction func-tion for the test star tracker, which causes an apparent periodic deflection in the inter-boresight angle between the two star trackers with respect to each other of up to ±500 arcsec, so the preces-sion and nutation effect needs to be considered while assessing the test star tracker. This paper researches on the precession-nutation correction for the test star tracker’s attitude measurement and presents a precession-nutation correction method based on attitude quaternion data. The peri-odic deflection of the inter-boresight angle between the two star trackers has been greatly eliminated after the precession and nutation of the test star tracker’s attitude data have been corrected by the proposed method and the validity of the proposed algorithm has been demonstrated. The in-flight accuracy of the test star tracker has been assessed like attitude noise and low-frequency errors after the precession-nutation correction.

  10. An Integrated Tracker for STAR

    OpenAIRE

    Simon, Frank; Collaboration, for the STAR

    2006-01-01

    The STAR experiment at the Relativistic Heavy Ion Collider RHIC studies the new state of matter produced in relativistic heavy ion collisions and the spin structure of the nucleon in collisions of polarized protons. In order to improve the capabilities for heavy flavor measurements and the reconstruction of charged vector bosons an upgrade of the tracking system both in the central and the forward region is pursued. The integrated system providing high resolution tracking and secondary vertex...

  11. Precision Pointing Control System (PPCS) star tracker test

    Science.gov (United States)

    1972-01-01

    Tests performed on the TRW precision star tracker are described. The unit tested was a two-axis gimballed star tracker designed to provide star LOS data to an accuracy of 1 to 2 sec. The tracker features a unique bearing system and utilizes thermal and mechanical symmetry techniques to achieve high precision which can be demonstrated in a one g environment. The test program included a laboratory evaluation of tracker functional operation, sensitivity, repeatibility, and thermal stability.

  12. An Integrated Tracker for STAR

    CERN Document Server

    Simon, F

    2006-01-01

    The STAR experiment at the Relativistic Heavy Ion Collider RHIC studies the new state of matter produced in relativistic heavy ion collisions and the spin structure of the nucleon in collisions of polarized protons. In order to improve the capabilities for heavy flavor measurements and the reconstruction of charged vector bosons an upgrade of the tracking system both in the central and the forward region is pursued. The integrated system providing high resolution tracking and secondary vertex reconstruction capabilities will use silicon pixel, strip and GEM technology.

  13. Microsatellite Star Tracker Baffles: Validation and Testing

    OpenAIRE

    Marciniak, Martin; Enright, John; Sinclair, Doug; Dzamba, Tom

    2013-01-01

    In this paper, we examine the challenges of ground-based stray light testing from a microsatellite perspective. We consider some of the historical approaches to simulation and laboratory testing and propose strategies for ground validation that require only modest investment in test facilities. The star tracker or instrument is characterized in the lab without any baffle, using a novel technique to subtract out reflections internal to the test chamber. From the resulting data a simulation ele...

  14. Star Tracker Cost Reduction for Small Satellites

    OpenAIRE

    Delabie, Tjorven; DE SCHUTTER, JORIS; Vandenbussche, Bart

    2014-01-01

    In recent years, the great potential of small satellites has become ever clearer and small satellites are selected to perform increasingly complex missions. With this rise in mission complexity, the requirements on the Attitude Determination and Control System of the satellite increase as well. Of all the attitude determination sensors, the star tracker is by far the most accurate one. The accuracy of this sensor is in the order of arc seconds. The disadvantages of this sensor are that it...

  15. Lightweight, Low-Power Coarse Star Tracker

    OpenAIRE

    Zenick, Ray; McGuire, Thomas

    2003-01-01

    General industry research on spacecraft attitude determination and control components is focused on increasing accuracy to the exclusion of all else. This is contrary to the clear requirement for decreased complexity, mass, and power consumption to fit the needs of small, maneuverable, low-cost spacecraft. To address this need, AeroAstro and the Massachusetts Institute of Technology Space Systems Laboratory are developing a coarse star tracker, which strikes an appropriate balance between acc...

  16. A Heavy-Flavor Tracker for STAR

    CERN Document Server

    Schweda, K

    2006-01-01

    We propose to construct a heavy flavor tracker for the STAR experiment at RHIC in order to measure the elliptic flow of charmed hadrons in the low pt region and identify B-meson contributions in the region pt > 4 GeV/c. In this talk, we will present the design of the detector in-depth and its expected performance as studied in detailed simulations and analytic calculations. Physics potentials of the detector will also be discussed.

  17. A Brightness-Referenced Star Identification Algorithm for APS Star Trackers

    OpenAIRE

    Peng Zhang; Qile Zhao; Jingnan Liu; Ning Liu

    2014-01-01

    Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD)-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS) star trackers, the intensity of an imaged star is valuable information that can be used in star identification process...

  18. Autonomous orientation for LEO spacecraft using multi-FOV star tracker%多视场星敏感器近地轨道自主定位导航方法

    Institute of Scientific and Technical Information of China (English)

    魏新国; 李延鹏; 李健; 江洁

    2014-01-01

    传统航天器自主天文导航需要星敏感器、红外地平仪、磁强计等多种敏感器采集导航数据,增加了航天器的成本和复杂度。利用多视场星敏感器的特点,分别对恒星与地球进行成像,在完成姿态测量的同时,得到地心矢量信息,从而进行自主天文导航。首先建立地球几何模型,结合航天器轨道参数与多视场星敏感器的安装布局,实现各个视场内地球边缘的成像模拟,使用Steger算法提取地球边缘。综合考虑地球扁率的影响,对不同视场中观测到的地球边缘进行拟合得到精确地心矢量,最后进行基于星光角距的直接敏感地平导航仿真。仿真结果表明,在一个视场观测恒星,另外两个视场观测地球边缘的布局情况下,地心矢量精度和导航位置精度分别达到0.0172º(1σ)和190 m(1σ)。%The traditional methods for spacecraft autonomous navigation need several sensors, such as star sensor, infrared horizon sensor and magnetometer, to collect navigation data. As a result the load of spacecraft will gain in weight, size and power. Based on the advantages of multi- field of view (FOV) star tracker, an autonomous navigation method was proposed which used multi- FOV star tracker (MFST) to image the star and the earth respectively and got the orientation vectors of them. Combining with the orbit parameters of the spacecraft and the layout of the MFST, a mathematic model of the earth imaging was set up to implement the earth edge images in every single FOV. The Steger method was used to determine the earth edge in the images. Considering the earth oblateness, the orientation vector of the earth will be obtained through circle- fitting the earth edge points in each FOV. With the configuration that one FOV measures the navigation star and the other two FOV measures the earth edge, the autonomous orientation based on the starlight angle is simulated and the result indicates that

  19. Intermediate Silicon Tracker for STAR HFT Upgrade

    Science.gov (United States)

    Wang, Yaping

    2013-04-01

    The STAR experiment at the Relative Heavy Ion Collider in Brookhaven National Laboratory at Upton, NY will soon be upgraded with the a Heavy Flavor Tracker (HFT), which will greatly enhance the capability for heavy flavor studies by measurements of displaced vertices and direct topological reconstruction of open charm hadrons. The HFT consists of 4 layers of silicon detectors. The Intermediate Silicon Tracker (IST) is one of these layers. It uses conventional silicon pad sensors, which provide a position resolution of about 180 (1800) microns in the r-phi (longitudinal) direction. The IST detector is in production now so that it will be ready for installation in Fall 2013. In this talk, we will present the design and performance of the IST, and the status of the production.

  20. Attitude determination using Star Tracker Data with Kalman filters

    OpenAIRE

    Travis, Henry D.

    2001-01-01

    This study adapts some established attitude determination techniq ues for use with star tracker measurements on satellites. Other work in this area has utilized gyro measurements with star tracker updates. Todayαs star trackers are giving measurements with accuracies of less than 6 arcseconds, and are therefore of high enough fidelity to be used alone. Computer simulation of a Linear Kalman Filter to process these measurements is presented. The Filter uses a linear, constant coefficient stat...

  1. Exposure Time Optimization for Highly Dynamic Star Trackers

    OpenAIRE

    Xinguo Wei; Wei Tan; Jian Li; Guangjun Zhang

    2014-01-01

    Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect...

  2. Star tracker and vision systems performance in a high radiation environment

    OpenAIRE

    Jørgensen, John Leif; Riis, Troels; Betto, Maurizio

    1999-01-01

    A part of the payload of the second Ariane 5 prototype vehicle to be launched by Arianespace, was a small technology demonstration satellite. On October 30th, 1997, this test satellite, dubbed Teamsat, was launched into Geostationary Transfer Orbit and would as such pass the Van Allen radiation belts twice per orbit. One of the experiments onboard Teamsat was the so-called Autonomous Vision System (AVS). The AVS instrument is a fully autonomous star tracker with several advanced features for ...

  3. A Heavy Flavor Tracker for STAR

    International Nuclear Information System (INIS)

    The STAR Collaboration proposes to construct a state-of-the-art microvertex detector, the Heavy Flavor Tracker (HFT), utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precision measurement of the yields and spectra of particles containing heavy quarks. This will be accomplished through topological identification of D mesons by reconstruction of their displaced decay vertices with a precision of approximately 50 mu m in p+p, d+A, and A+A collisions. The HFT consists of 4 layers of silicon detectors grouped into two sub-systems with different technologies, guaranteeing increasing resolution when tracking from the TPC and the Silicon Strip Detector (SSD) towards the vertex of the collision. The Intermediate Silicon Tracker (IST), consisting of two layers of single-sided strips, is located inside the SSD. Two layers of Silicon Pixel Detector (PIXEL) are inside the IST. The PIXEL detectors have the resolution necessary for a precision measurement of the displaced vertex. The PIXEL detector will use CMOS Active Pixel Sensors (APS), an innovative technology never used before in a collider experiment. The APS sensors are only 50 mu m thick and at a distance of only 2.5 cm from the interaction point. This opens up a new realm of possibilities for physics measurements. In particular, a thin detector (0.28percent radiation length per layer) in STAR makes it possible to do the direct topological reconstruction of open charm hadrons down to very low pT by the identification of the charged daughters of the hadronic decay

  4. A Heavy Flavor Tracker for STAR

    Energy Technology Data Exchange (ETDEWEB)

    Chasman, C.; Beavis, D.; Debbe, R.; Lee, J.H.; Levine, M.J.; Videbaek, F.; Xu, Z.; Kleinfelder, S.; Li, S.; Cendejas, R.; Huang, H.; Sakai, S.; Whitten, C.; Joseph, J.; Keane, D.; Margetis, S.; Rykov, V.; Zhang, W.M.; Bystersky, M.; Kapitan, J.; Kushpil, V.; Sumbera, M.; Baudot, J.; Hu-Guo, C.; Shabetai, A.; Szelezniak, M.; Winter, M.; Kelsey, J.; Milner, R.; Plesko, M.; Redwine, R.; Simon, F.; Surrow, B.; Van Nieuwenhuizen, G.; Anderssen, E.; Dong, X.; Greiner, L.; Matis, H.S.; Morgan, S.; Ritter, H.G.; Rose, A.; Sichtermann, E.; Singh, R.P.; Stezelberger, T.; Sun, X.; Thomas, J.H.; Tram, V.; Vu, C.; Wieman, H.H.; Xu, N.; Hirsch, A.; Srivastava, B.; Wang, F.; Xie, W.; Bichsel, H.

    2008-02-25

    The STAR Collaboration proposes to construct a state-of-the-art microvertex detector,the Heavy Flavor Tracker (HFT), utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precision measurement of the yields and spectra of particles containing heavy quarks. This will be accomplished through topological identification of D mesons by reconstruction of their displaced decay vertices with a precision of approximately 50 mu m in p+p, d+A, and A+A collisions. The HFT consists of 4 layers of silicon detectors grouped into two sub-systems with different technologies, guaranteeing increasing resolution when tracking from the TPC and the Silicon Strip Detector (SSD) towards the vertex of the collision. The Intermediate Silicon Tracker (IST), consisting of two layers of single-sided strips, is located inside the SSD. Two layers of Silicon Pixel Detector (PIXEL) are inside the IST. The PIXEL detectors have the resolution necessary for a precision measurement of the displaced vertex. The PIXEL detector will use CMOS Active Pixel Sensors (APS), an innovative technology never used before in a collider experiment. The APSsensors are only 50 mu m thick and at a distance of only 2.5 cm from the interaction point. This opens up a new realm of possibilities for physics measurements. In particular, a thin detector (0.28percent radiation length per layer) in STAR makes it possible to do the direct topological reconstruction of open charm hadrons down to very low pT by the identification of the charged daughters of the hadronic decay.

  5. Documentation for delivery of Star Tracker to PROBA

    DEFF Research Database (Denmark)

    Thuesen, Gøsta; Riis, Troels; Madsen, Peter Buch;

    1999-01-01

    The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the flight hardware of the Star Tracker for the ESA satellite PROBA.......The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the flight hardware of the Star Tracker for the ESA satellite PROBA....

  6. Documentation for delivery of Star Tracker to CHAMP

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Betto, Maurizio; Jørgensen, John Leif;

    1999-01-01

    The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the flight hardware of the Star Tracker for the German satellite CHAMP.......The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the flight hardware of the Star Tracker for the German satellite CHAMP....

  7. Documentation for delivery of Star Tracker to ADEOS II

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Betto, Maurizio; Denver, Troelz;

    1999-01-01

    The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the Flight Hardware of the Star Tracker for the Japanese satellite ADEOS II.......The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the Flight Hardware of the Star Tracker for the Japanese satellite ADEOS II....

  8. A low-cost, CCD solid state star tracker

    Science.gov (United States)

    Chmielowski, M.; Wynne, D.

    1992-01-01

    Applied Research Corporation (ARC) has developed an engineering model of a multi-star CCD-based tracker for space applications requiring radiation hardness, high reliability and low power consumption. The engineering unit compared favorably in functional performance tests to the standard NASA single-star tracker. Characteristics of the ARC star tracker are: field of view = 10 deg x 7.5 deg, sensitivity range of -1 to +5 star magnitude, NEA = 3 in x 3 in, linearity = 5 in x 5 in, and power consumption of 1-3 W (operating mode dependent). The software is upgradable through a remote link. The hardware-limited acquisition rate is 1-5 Hz for stars of +2 to +5 magnitude and 10-30 Hz for -1 to +2 magnitude stars. Mechanical and electrical interfaces are identical to the standard NASA star tracker.

  9. Optimization of star research algorithm for esmo star tracker

    OpenAIRE

    Jalabert, Eva; Fabacher, Emilien; Guy, Nicolas; Lizy-Destrez, Stéphanie; Rappin, William; Rivier, Guillaume

    2011-01-01

    This paper explains in detail the design and the development of a software research star algorithm, embedded on a star tracker, by the ISAE/SUPAERO team. This research algorithm is inspired by musical techniques. This work will be carried out as part of the ESMO (European Student Moon Orbiter) project by different teams of students and professors from ISAE/SUPAERO (Institut Supe ́rieur de l’Ae ́ronautique et de l’Espace). Till today, the system engineering studies have been completed and the ...

  10. Forward GEM Tracker (FGT) at STAR

    Science.gov (United States)

    Surrow, Bernd

    2012-10-01

    As part of our program to understand the internal structure of the proton, we have and will continue mid-rapidity (-1anti-d quarks to the proton spin. The gluon spin contribution can be probed through di-jet measurements. The Forward GEM Tracker (FGT) at STAR will enhance the charged sign separation for high pT tracks in the pseudo-rapidity range of 1.0<η<2.0, and therefore allows an extension of W and di-jet measurements at forward pseudo-rapidity. We will present the status of the FGT assembly and completion along with projections for future W and di-jet measurements. We will discuss studies that explore the possibilities of using the FGT to reconstruct jets in the forward direction.

  11. High Energy Astronomy Observatory star tracker search program

    Science.gov (United States)

    Weiler, W. J.

    1972-01-01

    The development of a control system to accommodate the scientific payload of the High Energy Astronomy Observatory (HEAO) is discussed. One of the critical elements of the system is the star tracker subsystem, which defines an accurate three-axis attitude reference. A digital computer program has been developed to evaluate the ability of a particular star tracker configuration to meet the requirements for attitude reference at various vehicle orientations. Used in conjuction with an adequate star catalog, the computer program provides information on availability of stars for each tracker and on the ability of the system to maintain three-axis attitude reference throughout a representative sequence of vehicle orientations.

  12. Exposure Time Optimization for Highly Dynamic Star Trackers

    Directory of Open Access Journals (Sweden)

    Xinguo Wei

    2014-03-01

    Full Text Available Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers.

  13. Exposure time optimization for highly dynamic star trackers.

    Science.gov (United States)

    Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun

    2014-01-01

    Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers. PMID:24618776

  14. On Random and Systematic Errors of a Star Tracker

    OpenAIRE

    Tuchin, Maksim; Biryukov, Anton; Nickiforov, Mikhail; Prokhorov, Mikhail; Zakharov, Andrey

    2013-01-01

    The error of the attitude of many modern star trackers is determined by systematic errors. In this paper we consider the effect of random and different systematic errors of sensors on the attitude accuracy of star trackers. The results of modeling of principal systematic errors, first of all, due to underestimation of the dark current inhomogeneity, are discussed. It is shown that only this systematic error can decrease the attitude accuracy of a star tracker by a factor of 3–4. Methods of ta...

  15. EOS attitude determination and next generation star tracker enhancements

    Science.gov (United States)

    Kudva, P.; Throckmorton, A.

    1993-01-01

    The pointing knowledge required for the Earth Observing System (EOS) AM mission is at the limit of the current generation of star trackers, with little margin. Techniques for improving the performance of existing star trackers are explored, with performance sensitivities developed for each alternative. These are extended to define the most significant performance enhancements for a next generation star tracker. Since attitude determination studies tend to be computationally intensive, an approach for using a simpler one degree of freedom formulation is contrasted with a full three degree of freedom formulation. Additionally, covariance analysis results are compared with time domain simulation performance results.

  16. Simulation analysis of dynamic working performance for star trackers.

    Science.gov (United States)

    Shen, Juan; Zhang, Guangjun; Wei, Xinguo

    2010-12-01

    The elongated imaging track pertaining to a star spot recorded in the image sensor of a star tracker will diffuse over several pixels at a high angular velocity, leading to an inaccurate, even false, attitude value. A computer simulation of the attitude determination from a dynamic star tracker is developed first, based on a dynamic mathematical model of the star-spot imaging and an efficiency validation of the star centroiding algorithm in the dynamic condition. Then major error sources affecting the attitude accuracy in the dynamic condition are analyzed and discussed systematically based on the simulation results. A mathematical model calculating the average star number detected in the field of view is also deduced, using simulation results and signal processing theory, with image trailing ranging from 0 to 20 pixels during exposure. The summarized regularity is helpful in the system design and accuracy evaluation of a star tracker. PMID:21119749

  17. Lost in space: Onboard star identification using CCD star tracker data without an a priori attitude

    Science.gov (United States)

    Ketchum, Eleanor A.; Tolson, Robert H.

    1993-01-01

    There are many algorithms in use today which determine spacecraft attitude by identifying stars in the field of view of a star tracker. Some methods, which date from the early 1960's, compare the angular separation between observed stars with a small catalog. In the last 10 years, several methods have been developed which speed up the process and reduce the amount of memory needed, a key element to onboard attitude determination. However, each of these methods require some a priori knowledge of the spacecraft attitude. Although the Sun and magnetic field generally provide the necessary coarse attitude information, there are occasions when a spacecraft could get lost when it is not prudent to wait for sunlight. Also, the possibility of efficient attitude determination using only the highly accurate CCD star tracker could lead to fully autonomous spacecraft attitude determination. The need for redundant coarse sensors could thus be eliminated at substantial cost reduction. Some groups have extended their algorithms to implement a computation intense full sky scan. Some require large data bases. Both storage and speed are concerns for autonomous onboard systems. Neural network technology is even being explored by some as a possible solution, but because of the limited number of patterns that can be stored and large overhead, nothing concrete has resulted from these efforts. This paper presents an algorithm which, by descretizing the sky and filtering by visual magnitude of the brightness observed star, speeds up the lost in space star identification process while reducing the amount of necessary onboard computer storage compared to existing techniques.

  18. Interferometric Star Tracker for High Precision Pointing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Optical Physics Company (OPC) proposes to adapt the precision star tracker it is currently developing under several DoD contracts for deep space lasercom beam...

  19. Gaussian Analytic Centroiding method of star image of star tracker

    Science.gov (United States)

    Wang, Haiyong; Xu, Ershuai; Li, Zhifeng; Li, Jingjin; Qin, Tianmu

    2015-11-01

    The energy distribution of an actual star image coincides with the Gaussian law statistically in most cases, so the optimized processing algorithm about star image centroiding should be constructed also by following Gaussian law. For a star image spot covering a certain number of pixels, the marginal distribution of the gray accumulation on rows and columns are shown and analyzed, based on which the formulas of Gaussian Analytic Centroiding method (GAC) are deduced, and the robustness is also promoted due to the inherited filtering effect of gray accumulation. Ideal reference star images are simulated by the PSF (point spread function) with integral form. Precision and speed tests for the Gaussian Analytic formulas are conducted under three scenarios of Gaussian radius (0.5, 0.671, 0.8 pixel), The simulation results show that the precision of GAC method is better than that of the other given algorithms when the Gaussian radius is not bigger than 5 × 5 pixel window, a widely used parameter. Above all, the algorithm which consumes the least time is still the novel GAC method. GAC method helps to promote the comprehensive performance in the attitude determination of a star tracker.

  20. Documentation for delivery of Star Tracker to SAC-C

    DEFF Research Database (Denmark)

    Kilsgaard, Søren; Thuesen, Gøsta; Riis, Troels;

    1999-01-01

    The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the flight hardware of the Star Tracker for the Argentine, Danish and NASA satellite SAC-C.......The documentation EIDP (End Item Data Package) describes all the tests which have been performed on the flight hardware of the Star Tracker for the Argentine, Danish and NASA satellite SAC-C....

  1. Optical Alignment of the Global Precipitation Measurement (GPM) Star Trackers

    Science.gov (United States)

    Hetherington, Samuel; Osgood, Dean; McMann, Joe; Roberts, Viki; Gill, James; Mclean, Kyle

    2013-01-01

    The optical alignment of the star trackers on the Global Precipitation Measurement (GPM) core spacecraft at NASA Goddard Space Flight Center (GSFC) was challenging due to the layout and structural design of the GPM Lower Bus Structure (LBS) in which the star trackers are mounted as well as the presence of the star tracker shades that blocked line-of-sight to the primary star tracker optical references. The initial solution was to negotiate minor changes in the original LBS design to allow for the installation of a removable item of ground support equipment (GSE) that could be installed whenever measurements of the star tracker optical references were needed. However, this GSE could only be used to measure secondary optical reference cube faces not used by the star tracker vendor to obtain the relationship information and matrix transformations necessary to determine star tracker alignment. Unfortunately, due to unexpectedly large orthogonality errors between the measured secondary adjacent cube faces and the lack of cube calibration data, we required a method that could be used to measure the same reference cube faces as originally measured by the vendor. We describe an alternative technique to theodolite auto-collimation for measurement of an optical reference mirror pointing direction when normal incidence measurements are not possible. This technique was used to successfully align the GPM star trackers and has been used on a number of other NASA flight projects. We also discuss alignment theory as well as a GSFC-developed theodolite data analysis package used to analyze angular metrology data.

  2. Real-Time Hardware-in-the-Loop Tests of Star Tracker Algorithms

    Directory of Open Access Journals (Sweden)

    Giancarlo Rufino

    2013-01-01

    Full Text Available This paper deals with star tracker algorithms validation based on star field scene simulation and hardware-in-the-loop test configuration. A laboratory facility for indoor tests, based on the simulation of star field scenes, is presented. Attainable performance is analyzed theoretically for both static and dynamic simulations. Also, a test campaign is presented, in which a star sensor prototype with real-time, fully autonomous capability is exploited. Results that assess star field scene simulation performance and show the achievable validation for the sensor algorithms and performance in different operating modes (autonomous attitude acquisition, attitude tracking, and angular rate-only and different aspects (coverage, reliability, and measurement performance are discussed.

  3. On-Orbit Solar Dynamics Observatory (SDO) Star Tracker Warm Pixel Analysis

    Science.gov (United States)

    Felikson, Denis; Ekinci, Matthew; Hashmall, Joseph A.; Vess, Melissa

    2011-01-01

    This paper describes the process of identification and analysis of warm pixels in two autonomous star trackers on the Solar Dynamics Observatory (SDO) mission. A brief description of the mission orbit and attitude regimes is discussed and pertinent star tracker hardware specifications are given. Warm pixels are defined and the Quality Index parameter is introduced, which can be explained qualitatively as a manifestation of a possible warm pixel event. A description of the algorithm used to identify warm pixel candidates is given. Finally, analysis of dumps of on-orbit star tracker charge coupled devices (CCD) images is presented and an operational plan going forward is discussed. SDO, launched on February 11, 2010, is operated from the NASA Goddard Space Flight Center (GSFC). SDO is in a geosynchronous orbit with a 28.5 inclination. The nominal mission attitude points the spacecraft X-axis at the Sun, with the spacecraft Z-axis roughly aligned with the Solar North Pole. The spacecraft Y-axis completes the triad. In attitude, SDO moves approximately 0.04 per hour, mostly about the spacecraft Z-axis. The SDO star trackers, manufactured by Galileo Avionica, project the images of stars in their 16.4deg x 16.4deg fields-of-view onto CCD detectors consisting of 512 x 512 pixels. The trackers autonomously identify the star patterns and provide an attitude estimate. Each unit is able to track up to 9 stars. Additionally, each tracker calculates a parameter called the Quality Index, which is a measure of the quality of the attitude solution. Each pixel in the CCD measures the intensity of light and a warns pixel is defined as having a measurement consistently and significantly higher than the mean background intensity level. A warns pixel should also have lower intensity than a pixel containing a star image and will not move across the field of view as the attitude changes (as would a dim star image). It should be noted that the maximum error introduced in the star tracker

  4. Improved autonomous star identification algorithm

    Science.gov (United States)

    Luo, Li-Yan; Xu, Lu-Ping; Zhang, Hua; Sun, Jing-Rong

    2015-06-01

    The log-polar transform (LPT) is introduced into the star identification because of its rotation invariance. An improved autonomous star identification algorithm is proposed in this paper to avoid the circular shift of the feature vector and to reduce the time consumed in the star identification algorithm using LPT. In the proposed algorithm, the star pattern of the same navigation star remains unchanged when the stellar image is rotated, which makes it able to reduce the star identification time. The logarithmic values of the plane distances between the navigation and its neighbor stars are adopted to structure the feature vector of the navigation star, which enhances the robustness of star identification. In addition, some efforts are made to make it able to find the identification result with fewer comparisons, instead of searching the whole feature database. The simulation results demonstrate that the proposed algorithm can effectively accelerate the star identification. Moreover, the recognition rate and robustness by the proposed algorithm are better than those by the LPT algorithm and the modified grid algorithm. Project supported by the National Natural Science Foundation of China (Grant Nos. 61172138 and 61401340), the Open Research Fund of the Academy of Satellite Application, China (Grant No. 2014_CXJJ-DH_12), the Fundamental Research Funds for the Central Universities, China (Grant Nos. JB141303 and 201413B), the Natural Science Basic Research Plan in Shaanxi Province, China (Grant No. 2013JQ8040), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20130203120004), and the Xi’an Science and Technology Plan, China (Grant. No CXY1350(4)).

  5. A star identification algorithm based on a voting scheme for star trackers

    OpenAIRE

    M. Hamidi; F. Samadzadegan

    2014-01-01

    Star identification is one of the most important stages in attitude determination with star trackers. This can be performed using matching algorithms between observed stars and a master star catalogue. The main challenge in this approach is to provide a fast and reliable identification algorithm that is sufficiently robust in different pointing views of the star tracker optical system in the space. In this article, an identification algorithm based on a geometric voting scheme is presented. I...

  6. Multi-functional star tracker — future perspectives

    OpenAIRE

    J. Roháč; M. Řeřábek; R. Hudec(Czech Technical University in Prague, Faculty of electrical Engineering and Astronomical Institute, Academy of Science of the Czech Republic, Czech Republic)

    2011-01-01

    This paper focuses on the idea of a multi-functional wide-field star tracker (WFST) and provides a description of the current state-of-the-art in this field. The idea comes from a proposal handed in to ESA at the beginning of 2011. Star trackers (STs) usually have more than one object-lens with a small Field-of-View. They provide very precise information about the attitude in space according to consecutive evaluation of star positions. Our idea of WFST will combine the functions of several in...

  7. System and method for calibrating inter-star-tracker misalignments in a stellar inertial attitude determination system

    Science.gov (United States)

    Li, Rongsheng (Inventor); Wu, Yeong-Wei Andy (Inventor); Hein, Douglas H. (Inventor)

    2004-01-01

    A method and apparatus for determining star tracker misalignments is disclosed. The method comprises the steps of defining a defining a reference frame for the star tracker assembly according to a boresight of the primary star tracker and a boresight of a second star tracker wherein the boresight of the primary star tracker and a plane spanned by the boresight of the primary star tracker and the boresight of the second star tracker at least partially define a datum for the reference frame for the star tracker assembly; and determining the misalignment of the at least one star tracker as a rotation of the defined reference frame.

  8. A brightness-referenced star identification algorithm for APS star trackers.

    Science.gov (United States)

    Zhang, Peng; Zhao, Qile; Liu, Jingnan; Liu, Ning

    2014-01-01

    Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD)-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS) star trackers, the intensity of an imaged star is valuable information that can be used in star identification process. In this paper an improved brightness referenced star identification algorithm is presented. This algorithm utilizes the k-vector search theory and adds imaged stars' intensities to narrow the search scope and therefore increase the efficiency of the matching process. Based on different imaging conditions (slew, bright bodies, etc.) the developed matching algorithm operates in one of two identification modes: a three-star mode, and a four-star mode. If the reference bright stars (the stars brighter than three magnitude) show up, the algorithm runs the three-star mode and efficiency is further improved. The proposed method was compared with other two distinctive methods the pyramid and geometric voting methods. All three methods were tested with simulation data and actual in orbit data from the APS star tracker of ZY-3. Using a catalog composed of 1500 stars, the results show that without false stars the efficiency of this new method is 4~5 times that of the pyramid method and 35~37 times that of the geometric method. PMID:25299950

  9. Space shuttle orbiter vehicle star tracker test program plan

    Science.gov (United States)

    Smith, R. A.

    1974-01-01

    The development model test program was written to provide guidance for essential star tracker test support to the Space Shuttle Orbiter Program. The program organization included test equipment preparation, prototype baseline/acceptance tests, prototype total performance tests, and prototype special tests. Test configurations, preparation phase, documentation, scheduling, and manpower requirements are discussed. The test program permits an early evaluation of the tracker's performance prior to completion and testing of the final flight models.

  10. A Novel Gyro-less Tracking Method for Star Tracker

    OpenAIRE

    Mehdi Nasiri-Sarvi*1

    2014-01-01

    In this paper a new tracking method is presented, which is one of the most important and useful algorithms in the stat tracker normal mode. the developed algorithm is gyro less algorithm without need to angular speed information of satellite. The presented algorithm was realized and tested on the fabricated star tracker (ROJA1) in Nanoptronics research center located at faculty of electrical engineering, Iran University of Science and Technology.

  11. A Brightness-Referenced Star Identification Algorithm for APS Star Trackers

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2014-10-01

    Full Text Available Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS star trackers, the intensity of an imaged star is valuable information that can be used in star identification process. In this paper an improved brightness referenced star identification algorithm is presented. This algorithm utilizes the k-vector search theory and adds imaged stars’ intensities to narrow the search scope and therefore increase the efficiency of the matching process. Based on different imaging conditions (slew, bright bodies, etc. the developed matching algorithm operates in one of two identification modes: a three-star mode, and a four-star mode. If the reference bright stars (the stars brighter than three magnitude show up, the algorithm runs the three-star mode and efficiency is further improved. The proposed method was compared with other two distinctive methods the pyramid and geometric voting methods. All three methods were tested with simulation data and actual in orbit data from the APS star tracker of ZY-3. Using a catalog composed of 1500 stars, the results show that without false stars the efficiency of this new method is 4~5 times that of the pyramid method and 35~37 times that of the geometric method.

  12. Miniature wide field-of-view star trackers for spacecraft attitude sensing and navigation

    Science.gov (United States)

    Mccarty, William; Curtis, Eric; Hull, Anthony; Morgan, William

    1993-01-01

    Introducing a family of miniature, wide field-of-view star trackers for low cost, high performance spacecraft attitude determination and navigation applications. These devices, derivative of the WFOV Star Tracker Camera developed cooperatively by OCA Applied Optics and the Lawrence Livermore National Laboratory for the Brilliant Pebbles program, offer a suite of options addressing a wide range of spacecraft attitude measurement and control requirements. These sensors employ much wider fields than are customary (ranging between 20 and 60 degrees) to assure enough bright stars for quick and accurate attitude determinations without long integration intervals. The key benefit of this approach are light weight, low power, reduced data processing loads and high information carrier rates for wide ACS bandwidths. Devices described range from the proven OCA/LLNL WFOV Star Tracker Camera (a low-cost, space-qualified star-field imager utilizing the spacecraft's own computer and centroiding and position-finding), to a new autonomous subsystem design featuring dual-redundant cameras and completely self-contained star-field data processing with output quaternion solutions accurate to 100 micro-rad, 3 sigma, for stand-alone applications.

  13. Star tracker operation in a high density proton field

    Science.gov (United States)

    Miklus, Kenneth J.; Kissh, Frank; Flynn, David J.

    1993-01-01

    Algorithms that reject transient signals due to proton effects on charge coupled device (CCD) sensors have been implemented in the HDOS ASTRA-l Star Trackers to be flown on the TOPEX mission scheduled for launch in July 1992. A unique technique for simulating a proton-rich environment to test trackers is described, as well as the test results obtained. Solar flares or an orbit that passes through the South Atlantic Anomaly can subject the vehicle to very high proton flux levels. There are three ways in which spurious proton generated signals can impact tracker performance: the many false signals can prevent or extend the time to acquire a star; a proton-generated signal can compromise the accuracy of the star's reported magnitude and position; and the tracked star can be lost, requiring reacquisition. Tests simulating a proton-rich environment were performed on two ASTRA-1 Star Trackers utilizing these new algorithms. There were no false acquisitions, no lost stars, and a significant reduction in reported position errors due to these improvements.

  14. A star pattern recognition algorithm for autonomous attitude determination

    Science.gov (United States)

    Van Bezooijen, R. W. H.

    1990-01-01

    The star-pattern recognition algorithm presented allows the advanced Full-sky Autonomous Star Tracker (FAST) device, such as the projected ASTROS II system of the Mariner Mark II planetary spacecraft, to reliably ascertain attitude about all three axes. An ASTROS II-based FAST, possessing an 11.5 x 11.5 deg field of view and 8-arcsec accuracy, can when integrated with an all-sky data base of 4100 guide stars determine its attitude in about 1 sec, with a success rate close to 100 percent. The present recognition algorithm can also be used for automating the acquisition of celestial targets by astronomy telescopes, autonomously updating the attitude of gyro-based attitude control systems, and automating ground-based attitude reconstruction.

  15. Simulations of silicon vertex tracker for star experiment at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Odyniec, G.; Cebra, D.; Christie, W.; Naudet, C.; Schroeder, L.; Wilson, W. [Lawrence Berkeley Lab., CA (United States); Liko, D. [Institut fur Hochenenergiephysik, Vienna, (Austria); Cramer, J.; Prindle, D.; Trainor, T. [Univ. of Washington, Seattle (United States); Braithwaite, W. [Univ. of Arkansas, Little Rock (United States)

    1991-12-31

    The first computer simulations to optimize the Silicon Vertex Tracker (SVT) designed for the STAR experiment at RHIC are presented. The physics goals and the expected complexity of the events at RHIC dictate the design of a tracking system for the STAR experiment. The proposed tracking system will consist of a silicon vertex tracker (SVT) to locate the primary interaction and secondary decay vertices and to improve the momentum resolution, and a time projection chamber (TPC), positioned inside a solenoidal magnet, for continuous tracking.

  16. Star tracker error analysis: Roll-to-pitch nonorthogonality

    Science.gov (United States)

    Corson, R. W.

    1979-01-01

    An error analysis is described on an anomaly isolated in the star tracker software line of sight (LOS) rate test. The LOS rate cosine was found to be greater than one in certain cases which implied that either one or both of the star tracker measured end point unit vectors used to compute the LOS rate cosine had lengths greater than unity. The roll/pitch nonorthogonality matrix in the TNB CL module of the IMU software is examined as the source of error.

  17. Qualification of the next generation of Star Tracker using COTS

    DEFF Research Database (Denmark)

    Guldager, Peter Buch; Aage, Helle Karina

    2005-01-01

    The Star Tracker from ØRSTED•DTU is built by using COTS components (Commercial-Off-The-Shelf) and due to no radiation data exists on COTS components, the EEE components are tested for Radiation effects. The components, which are tested is the one from the same lot, which is going to be used for the...... flight equipment, if they pass the radiation test. The next generation of Star Tracker are using 3-volt technology and this document describes how the COTS components are upscreened for space and how the instrument is qualified for space. The components are TID irradiated and are irradiated until...

  18. Acoustic underwater navigation of the Phoenix Autonomous Underwater Vehicle using the DiveTracker system

    OpenAIRE

    Scrivener, Arthur W.

    1996-01-01

    Autonomous Underwater Vehicles (AUVs) require a navigation system in order to conduct useful functions. This research was an experimental investigation of the commercial DiveTracker underwater acoustic navigation system used onboard the NPS Phoenix AUV. Tests conducted with the DiveTracker system proved that the system could be used successfully in AUV navigation while submerged and revealed that more precise positioning could be obtained through postconditioning of the DiveTracker output ran...

  19. ASTROS - A sub-arcsec CCD star tracker

    Science.gov (United States)

    Stanton, R. H.; Alexander, J. W.; Dennison, E. W.; Glavich, T. A.; Salomon, P. M.

    1984-01-01

    The design and application of ASTROS (Advanced Star and Target Reference Optical Sensor) are described, with emphasis on performance test results acquired with a prototype system. The ASTROS tracker provides extremely precise measurements of star image coordinates as inputs to the Image Motion Compensation (IMC) system used to stabilize the science instrument focal planes. Performance levels achieved are dramatic improvements over the levels achieved with image dissector designs with comparable fields of view.

  20. Star tracker and vision systems performance in a high radiation environment

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Riis, Troels; Betto, Maurizio

    1999-01-01

    belts twice per orbit. One of the experiments onboard Teamsat was the so-called Autonomous Vision System (AVS). The AVS instrument is a fully autonomous star tracker with several advanced features for non-stellar object detection and tracking, real-time image compression and transmission. The objectives...... for the AVS in Teamsat were to test these functions, to validate their autonomous operation in space, and to assess the operational constraints of a high radiation environment on such processes. This paper describes the AVS experiment, and the radiation flux experienced onboard TEAMSAT. This overview...... is followed by examples of the radiation impact on the AVS instrument flown onboard the TEAMSAT, and finally the operations of the various countermeasures are discussed....

  1. Multi-functional star tracker — future perspectives

    Directory of Open Access Journals (Sweden)

    J. Roháč

    2011-01-01

    Full Text Available This paper focuses on the idea of a multi-functional wide-field star tracker (WFST and provides a description of the current state-of-the-art in this field. The idea comes from a proposal handed in to ESA at the beginning of 2011. Star trackers (STs usually have more than one object-lens with a small Field-of-View. They provide very precise information about the attitude in space according to consecutive evaluation of star positions. Our idea of WFST will combine the functions of several instruments, e.g. ST, a horizon sensor, and an all-sky photometry camera. WFST will use a fish-eye lens. There is no comparable product on the present-day market. Nowadays, spacecraft have to carry several instruments for these applications. This increases the weight of the instrumentation and reduces the weight available for the payload.

  2. Clementine Star Tracker Stellar Compass: Final report part 1

    Energy Technology Data Exchange (ETDEWEB)

    Priest, R.E.; Kordas, J.F.; Lewis, I.T. [and others

    1995-07-01

    The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star stracker stellar compasses (star tracker camera + stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 x 384 focal plane array and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 m{sub v}, providing rms pointing accuracy of better than 100 {mu}rad pitch and yaw and 450 {mu}rad roll. A description of this light-weight, low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights. Documentation generated during the design, analysis, build, test and characterization of the star tracker cameras are presented. Collectively, this documentation represents a small library of information for this camera, and may be used as a framework for producing copy units by commercial enterprises, and therefore satisfies a Department of Defense and Department of Energy goal to transfer technology to industry. However, the considerable knowledge gained from the experience of the individuals involved in the system trades, design, analysis, production, testing and characterization of the star tracker stellar compass is not contained in this documentation.

  3. A precision star tracker utilizing advanced techniques and materials

    Science.gov (United States)

    Gates, R. F.; Mcaloon, K. J.

    1976-01-01

    An image dissector star tracker has been developed which operates in the photon counting mode making it possible to utilize all digital electronics. A unique pulse processing circuit allows bright stars to be tracked as well as dim stars. Thermal mechanical stability has been greatly enhanced by fabricating a housing with graphite/epoxy composite material with a linear coefficient of thermal expansion near zero. Test results indicate the +10 Mv stars can be acquired and tracked, while position variation with star intensity is less than 2 arc seconds from 2.5 Mv to +10 Mv. The noise equivalent angle for a +8 Mv star is 3 arc seconds. Polynominal correction for remaining cross-coupling and nonlinearity reduced error over total 1 x 1 deg field to 1.5 arc seconds.

  4. Intern Develops Small, Inexpensive Star Tracker

    OpenAIRE

    Stewart, Kenneth A.

    2015-01-01

    Naval Postgraduate School (NPS) student Intern Julian Brown is just 21 years old, but don’t let his young age and boyish charm fool you. He is a serious scientist and is working to build a star tracking system at NPS designed to help very small satellites determine their orientation in space.

  5. Spacecraft Attitude Determination Simulation and Experiment to Improve the Efficiency of a Star Tracker

    OpenAIRE

    Houtz, Nathan; Frueh, Carolin, Dr.

    2015-01-01

    Knowing a spacecraft’s orientation is crucial for many vital functions. Attitude is often determined using a star tracker. Star tracker attitude determination must be fast and efficient given the limited on board computing resources. To determine its attitude, a star tracker must take an image of its environment, locate the stars in that image, recognize a pattern among those stars, match it with patterns in a catalog, and determine the rotation matrix that relates the spacecraft to the inert...

  6. COTS Detectors for Nanosatellite Star Trackers: A Case Study

    OpenAIRE

    Enright, John; Sinclair, Doug; Fernando, Christy

    2011-01-01

    In recent years, many imaging sensors for small satellites have adopted CMOS active pixel sensors. The Aptina MT9P031 in particular, has seen many adopters. This paper presents lessons learned from our experience integrating this detector with the Sinclair Interplanetary S3S Star Tracker. We present practical advice for handling and assembly and discuss strategies for maximizing image quality over the sensor lifetime. In particular, we characterize the noise characteristics from several units...

  7. Acquisition and track algorithms for the Astros star tracker

    Science.gov (United States)

    Shalom, E.; Alexander, J. W.; Stanton, R. H.

    1985-01-01

    The Astros star tracker has been designed for an employment with the Space Shuttle. An achievement of the performance levels needed has required critical trade-offs between the hardware design and the control algorithms. This paper provides a description of the development of the acquisition and track algorithms. Attention is given to an Astros system overview, a system firmware description, cluster evaluation, guide star selection, exposure time determination, video data input, update interval timing, exposure time sequencing full frame video A/D conversion, analog threshold for acquisition, minimum threshold determination, and the theoretical basis for the track algorithm.

  8. Ground Testing Strategies for Verifying the Slew Rate Tolerance of Star Trackers

    OpenAIRE

    Tom Dzamba; John Enright

    2014-01-01

    The performance of a star tracker is largely based on the availability of its attitude solution. Several methods exist to assess star tracker availability under both static and dynamic imaging conditions. However, these methods typically make various idealizations that can limit the accuracy of these results. This study aims to increase the fidelity of star tracker availability modeling by accounting for the effects of detection logic and pixel saturation on star detection. We achieve this by...

  9. Motion-blurred star acquisition method of the star tracker under high dynamic conditions.

    Science.gov (United States)

    Sun, Ting; Xing, Fei; You, Zheng; Wei, Minsong

    2013-08-26

    The star tracker is one of the most promising attitude measurement devices used in spacecraft due to its extremely high accuracy. However, high dynamic performance is still one of its constraints. Smearing appears, making it more difficult to distinguish the energy dispersive star point from the noise. An effective star acquisition approach for motion-blurred star image is proposed in this work. The correlation filter and mathematical morphology algorithm is combined to enhance the signal energy and evaluate slowly varying background noise. The star point can be separated from most types of noise in this manner, making extraction and recognition easier. Partial image differentiation is then utilized to obtain the motion parameters from only one image of the star tracker based on the above process. Considering the motion model, the reference window is adopted to perform centroid determination. Star acquisition results of real on-orbit star images and laboratory validation experiments demonstrate that the method described in this work is effective and the dynamic performance of the star tracker could be improved along with more identified stars and guaranteed position accuracy of the star point. PMID:24105556

  10. Precision Attitude Determination System (PADS) system design and analysis: Single-axis gimbal star tracker

    Science.gov (United States)

    1974-01-01

    The feasibility is evaluated of an evolutionary development for use of a single-axis gimbal star tracker from prior two-axis gimbal star tracker based system applications. Detailed evaluation of the star tracker gimbal encoder is considered. A brief system description is given including the aspects of tracker evolution and encoder evaluation. System analysis includes evaluation of star availability and mounting constraints for the geosynchronous orbit application, and a covariance simulation analysis to evaluate performance potential. Star availability and covariance analysis digital computer programs are included.

  11. A star identification algorithm based on a voting scheme for star trackers

    Directory of Open Access Journals (Sweden)

    M. Hamidi

    2014-04-01

    Full Text Available Star identification is one of the most important stages in attitude determination with star trackers. This can be performed using matching algorithms between observed stars and a master star catalogue. The main challenge in this approach is to provide a fast and reliable identification algorithm that is sufficiently robust in different pointing views of the star tracker optical system in the space. In this article, an identification algorithm based on a geometric voting scheme is presented. In this algorithm a pair of stars in the catalogue votes for a pair of stars in the image if angular distance between the stars of both pairs is similar. As angular distance is a symmetric relationship, each of the two catalogue stars votes for each of the image stars. The identity of each star in the image is set to the identity of the catalogue star which cast the most votes. Applying the algorithm in different attitudes and with different optical system parameters shows its high performance in star identification in our simulations.

  12. The STAR Heavy Flavor Tracker PXL detector readout electronics

    Science.gov (United States)

    Schambach, J.; Contin, G.; Greiner, L.; Stezelberger, T.; Sun, X.; Szelezniak, M.; Vu, C.

    2016-01-01

    The Heavy Flavor Tracker (HFT) is a recently installed micro-vertex detector upgrade to the STAR experiment at RHIC, consisting of three subsystems with various technologies of silicon sensors arranged in 4 concentric cylinders. The two innermost layers of the HFT close to the beam pipe, the Pixel ("PXL") subsystem, employ CMOS Monolithic Active Pixel Sensor (MAPS) technology that integrate the sensor, front-end electronics, and zero-suppression circuitry in one silicon die. This paper presents selected characteristics of the PXL detector part of the HFT and the hardware, firmware and software associated with the readout system for this detector.

  13. Ds Meson Reconstruction from STAR Heavy Flavor Tracker

    Science.gov (United States)

    Njoya, Oumarou

    2009-10-01

    Nucleus-Nucleus Collisions at RHIC (the Relativistic Heavy Ion Collider) have produced a strongly interacting dense partonic matter whose degrees of freedom are governed by the Quantum ChromoDynamics (QCD). The Solenoid Tracker At RHIC (STAR) is an ongoing major experiment which aims to study the properties of the QCD matter under extreme energy density, pressure, and temperature. Heavy quark production and propagation are unique probes to the dense matter created at RHIC. The HFT (Heavy Flavor Tracker) is a proposed detector upgrade of STAR, capable of reconstructing open charm hadrons from hadronic decay channels. We carry out a study of Ds meson reconstruction using GEANT simulations. We reconstruct Ds mesons through a 3-body decay of K^+K^-π at displaced vertices as a function of transverse momentum. We present preliminary results on the statistical significance of the reconstructed Ds signal as well as on the Ds detection efficiency using HFT. The physics impact of the Ds measurement will also be discussed.

  14. Adaptive Neural Star Tracker Calibration for Precision Spacecraft Pointing and Tracking

    Science.gov (United States)

    Bayard, David S.

    1996-01-01

    The Star Tracker is an essential sensor for precision pointing and tracking in most 3-axis stabilized spacecraft. In the interest (of) improving pointing performance by taking advantage of dramatic increases in flight computer power and memory anticipated over the next decade, this paper investigates the use of a neural net for adaptive in-flight calibration of the Star Tracker.

  15. Measurement of charm flow with the STAR Heavy Flavour Tracker

    International Nuclear Information System (INIS)

    In order to understand the partonic EOS of matter created at RHIC, one needs to study both the collectivity of the produced matter and the degree of thermalization. Anisotropic flow measurements have already demonstrated the development of partonic collectivity at RHIC (Ackermann K et al 2001 Phys. Rev. Lett. 86 402), and now it is necessary to address the issue of quark thermalization. Since the masses of the heavy flavour quarks are larger than the possible excitations of the system created in the collision, their collective motion could be used to indicate the degree of thermalization of the light flavour quarks (u, d, s). The Heavy Flavour Tracker (HFT), a tracking upgrade of the STAR experiment, is being designed to provide an unambiguous measurement of charm quark flow through the direct reconstruction of the D0. The current design of our detector uses a novel CMOS-based sensor, allowing for a low mass and high resolution detector element

  16. Angular velocity estimation from measurement vectors of star tracker.

    Science.gov (United States)

    Liu, Hai-bo; Yang, Jun-cai; Yi, Wen-jun; Wang, Jiong-qi; Yang, Jian-kun; Li, Xiu-jian; Tan, Ji-chun

    2012-06-01

    In most spacecraft, there is a need to know the craft's angular rate. Approaches with least squares and an adaptive Kalman filter are proposed for estimating the angular rate directly from the star tracker measurements. In these approaches, only knowledge of the vector measurements and sampling interval is required. The designed adaptive Kalman filter can filter out noise without information of the dynamic model and inertia dyadic. To verify the proposed estimation approaches, simulations based on the orbit data of the challenging minisatellite payload (CHAMP) satellite and experimental tests with night-sky observation are performed. Both the simulations and experimental testing results have demonstrated that the proposed approach performs well in terms of accuracy, robustness, and performance. PMID:22695598

  17. Optimal estimation for the satellite attitude using star tracker measurements

    Science.gov (United States)

    Lo, J. T.-H.

    1986-01-01

    An optimal estimation scheme is presented, which determines the satellite attitude using the gyro readings and the star tracker measurements of a commonly used satellite attitude measuring unit. The scheme is mainly based on the exponential Fourier densities that have the desirable closure property under conditioning. By updating a finite and fixed number of parameters, the conditional probability density, which is an exponential Fourier density, is recursively determined. Simulation results indicate that the scheme is more accurate and robust than extended Kalman filtering. It is believed that this approach is applicable to many other attitude measuring units. As no linearization and approximation are necessary in the approach, it is ideal for systems involving high levels of randomness and/or low levels of observability and systems for which accuracy is of overriding importance.

  18. Star trackers, star catalogs, and attitude determination - Probabilistic aspects of system design

    Science.gov (United States)

    Vedder, John D.

    1992-01-01

    Optimizing spacecraft attitude determination systems that use onboard star trackers requires analysis and evaluation of some probabilistic aspects of system design. This paper discusses methods of constructing or compiling optimum star catalogs, which are defined as uniform distributions on a sphere. Both local and global measures of uniformity on a sphere are defined. Application of these methods and measures to a specific problem is also discussed. In addition, Poisson models of star tracker acquisition probabilities are formulated to provide a useful analytical basis for designing and optimizing attitude determination systems. These analytical models and methods lead to rapid and realistic quantitative results, and should therefore facilitate making system performance trades. Use of such methods should also reduce the need for performing tedious computer simulations to obtain analogous results.

  19. TRACKER

    CERN Multimedia

    C. Barth

    2012-01-01

      Strip Tracker In the end of 2011, the Silicon Strip Tracker participated in the very successful heavy-ion collision data-taking. With zero downtime attributed to the Strip Tracker, CMS could achieve the excellent efficiency of 96%. Thus we were able to improve on the already good uptime during pp collisions, and completed an excellent year for the Strip Tracker. The shift of responsibility to raise the high voltages at the declaration of Stable Beams from the Tracker DOC to the central crew went smoothly. The new scheme is working reliably and we improved our automatic DQM and DCS SMS services. With this further improvement we plan to discontinue calling the TK DOC at each Stable Beam; so far the TK DOC personally checked all systems. The biggest effort of this Year-End Technical Stop was a comprehensive evaluation of the C6F14 cooling system performance with respect to future cold operation. The analysis allows a dedicated planning of system refurbishments to be executed during 2012 and LS1....

  20. Fast and Robust pointing and tracking using a second-generation star tracker

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Pickles, Andrew

    1998-01-01

    Second generation star trackers work by taking wide-angle optical pictures of star fields, correlating the image against a star catalogue in ROM, centroiding many stars to derive an accurate position and orientation. This paper describes a miniature instrument(10cm cube), fast and lightweight (850g...

  1. Optical System Error Analysis and Calibration Method of High-Accuracy Star Trackers

    OpenAIRE

    Zheng You; Fei Xing; Ting Sun

    2013-01-01

    The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star ...

  2. The Forward GEM Tracker of STAR at RHIC

    CERN Document Server

    Simon, F; Fatemi, R; Hasell, D; Kelsey, J; Majka, R; Page, B; Plesko, M; Underwood, D; Smirnov, N; Sowinski, J; Spinka, H; Surrow, B; Visser, G

    2008-01-01

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is in the process of designing and constructing a forward tracking system based on triple GEM technology. This upgrade is necessary to give STAR the capability to reconstruct and identify the charge sign of W bosons over an extended rapidity range through their leptonic decay mode into an electron (positron) and a neutrino. This will allow a detailed study of the flavor-separated spin structure of the proton in polarized p + p collisions uniquely available at RHIC. The Forward GEM Tracker FGT will consist of six triple GEM disks with an outer radius of ~39 cm and an inner radius of ~10.5 cm, arranged along the beam pipe, covering the pseudo-rapidity range from 1.0 to 2.0 over a wide range of collision vertices. The GEM foils will be produced by Tech-Etch, Inc. Beam tests with test detectors using 10 cm x 10 cm Tech-Etch GEM foils and a two dimensional orthogonal strip readout have demonstrated a spatial r...

  3. Systematic error analysis and compensation for high accuracy star centroid estimation of star tracker

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Subpixel centroid estimation is the most important star image location method of star tracker. This paper presents a theoretical analysis of the systematic error of subpixel centroid estimation algorithm utilizing frequency domain analysis under the con-sideration of sampling frequency limitation and sampling window limitation. Explicit expression of systematic error of cen-troid estimation is obtained, and the dependence of systematic error on Gaussian width of star image, actual star centroid loca-tion and the number of sampling pixels is derived. A systematic error compensation algorithm for star centroid estimation is proposed based on the result of theoretical analysis. Simulation results show that after compensation, the residual systematic errors of 3-pixel-and 5-pixel-windows’ centroid estimation are less than 2×10-3 pixels and 2×10-4 pixels respectively.

  4. Compensation for Time-Dependent Star Tracker Thermal Deformation on the Aqua Spacecraft

    Science.gov (United States)

    Hashmall, Joseph A.; Natanson, Gregory; Glickman, Jonathan; Sedlak, Joseph

    2004-01-01

    Analysis of attitude sensor data from the Aqua mission showed small but systematic differences between batch least-squares and extended Kalman filter attitudes. These differences were also found to be correlated with star tracker residuals, gyro bias estimates, and star tracker baseplate temperatures. This paper describes the analysis that shows that these correlations are all consistent with a single cause: time-dependent thermal deformation of star tracker alignments. These varying alignments can be separated into relative and common components. The relative misalignments can be determined and compensated for. The common misalignments can only be determined in special cases.

  5. Post flight analysis of NASA standard star trackers recovered from the solar maximum mission

    Science.gov (United States)

    Newman, P.

    1985-01-01

    The flight hardware returned after the Solar Maximum Mission Repair Mission was analyzed to determine the effects of 4 years in space. The NASA Standard Star Tracker would be a good candidate for such analysis because it is moderately complex and had a very elaborate calibration during the acceptance procedure. However, the recovery process extensively damaged the cathode of the image dissector detector making proper operation of the tracker and a comparison with preflight characteristics impossible. Otherwise, the tracker functioned nominally during testing.

  6. A Method for Detecting Resident Space Objects and Orbit Determination Based on Star Trackers and Image Analysis

    OpenAIRE

    Bengtsson Bernander, Karl

    2014-01-01

    Satellites commonly use onboard digital cameras, called star trackers. A star tracker determines the satellite's attitude, i.e. its orientation in space, by comparing star positions with databases of star patterns. In this thesis, I investigate the possibility of extending the functionality of star trackers to also detect the presence of resident space objects (RSO) orbiting the earth. RSO consist of both active satellites and orbital debris, such as inactive satellites, spent rocket stages a...

  7. TRACKER

    CERN Multimedia

    D. Strom

    2011-01-01

    Strip Tracker Since the June CMS Week, the Silicon Strip Tracker has had another period of excellent detector operation with more than 97% system uptime. The focus on stable proton physics collection was fruitful, as CMS recorded greater than 5 fb–1 by the completion of the 2011 pp run. Following the November machine development and technical stop, the Strip Tracker now aims to provide the highest quality data during the heavy-ion run. The detector health, measured by the fraction of alive channels, is largely stable at around 97.8%. Recent failures include a TOB control ring, which now requires redundancy, and a TEC control ring with intermittent failures. These will be investigated during the Year-End Technical Stop. Critical services are very stable. The cooling system has a low total leak rate of less than 1 kg per day, and the power supply exchange rate is less than 1 unit per month. Two operational changes recently went into effect to optimise data-taking efficiency: (1) a tripped power su...

  8. TRACKER

    CERN Multimedia

    Frank Hartmann

    2012-01-01

      Strip Tracker In general, the Strip Tracker is operating smoothly with the current peak instantaneous luminosity beyond 6.5E33, high L1 rate and large pile-up. With several improvements in automatic DQM checks and an enhanced SMS and e-mail service system plus additional audio alarms, we have reduced the work-load of our TK DOC and stopped the calls made at the beginning of each fill. We successfully collected more than two million cosmic tracks in peak mode during inter-fill periods before June, fulfilling the request from the Tracker alignment group. Around 500k cosmic tracks were also collected at zero Tesla. All planned special measurements, namely DCU calibration and I-V scans, have been taken during the YETS and other technical stops. A peak-mode run, a delay run and two HV scans have also been taken during early collisions at the initial low-lumi runs as well as during the fill where CMS had a problem with the magnet. The largest source of downtime comes from TIB-2.8.1 a.k.a. FED 101, ...

  9. TRACKER

    CERN Multimedia

    L. Demaria

    2011-01-01

    Strip Tracker The Silicon Strip Tracker has maintained excellent operational performance during the 2011 data-taking period. The increase of instantaneous luminosity up to 1033 cm-2s-1 did not introduce any new issues in the detector. The detector has collected high-quality physics data with an uptime greater than 98%. Sources of downtime have been identified and problems were properly addressed. Improved firmware in the Front-End Driver (FED) firmware was deployed to increase the robustness of the readout against spurious extra frames coming from the detector. When a FED detects bad data, it goes into Out-Of-Sync (OOS) status, waits for a L1 resynchronisation command (resync) to clean up the culprit data and restarts. Resync commands are now sent automatically to the Strip Tracker when it signals OOS and, as a result, this source of downtime has been reduced significantly. The dead-time, caused by recoveries from OOS, accounts for less than 0.1%. Downtime was also found to be caused by a FED occasionally ge...

  10. TRACKER

    CERN Multimedia

    G. Dirkes

    2010-01-01

    The strip system has generally exhibited stable and high performance operation during the last six months of pp and heavy ion collisions. The up-time during pp collision from June onwards was 99.0% and during the first weeks of heavy-ion running we reached 99.7%. Most of the down-time during the proton runs came from Tracker DAQ problems. Spurious extra events from individual front-end channels caused ‘sync loss draining’ errors at the central DAQ system downstream of the Tracker FEDs. Once the problem was understood, new firmware that detects this error condition was installed on the FEDs. This has reduced the recovery procedure from this particular condition from a full reconfiguration requiring 170 s, to a simple re-synchronisation taking only ~1 s. We have also streamlined the instructions for the central DAQ shifters in order to minimise the time needed to decide the proper reaction to a given problem. The average down-time for problems triggered by the strip tracker DAQ is 395 s. Th...

  11. The HFT, a Heavy Flavor Tracker for STAR

    International Nuclear Information System (INIS)

    Determining the degree of thermalization of the medium created in heavy ion collisions at RHIC remains highly debated. Elliptic flow (v2) measurements at RHIC have already suggested the development of collectivity among partons before hadronization. If heavy flavor hadrons flow with the light flavor hadrons, this indicates frequent interactions between the light (u,d,s) and heavy (c,b) quarks. Thus, thermalization of light quarks is likely to have been reached through partonic re-scattering. Experimentally this can be probed by making a direct measurement of D-mesons v2 with sufficient precision at low transverse momentum. Using the Heavy Flavor Tracker (HFT) detector, the STAR experiment at RHIC is proposing to both study this process and also to directly reconstruct charmed hadrons (D0, D+, Ds, ΛC,..), using the displaced vertices of their decay products. The HFT is the first vertex detector to use a new and promising CMOS active pixel sensor technology. It will allow to build a relatively fast, accurate and radiation tolerant detector, while keeping the material budget low (∝0.3%X0 per layer). Detector design and physics performance simulations are presented. (orig.)

  12. TAB Bonded SSD Module for the STAR and ALICE Trackers

    CERN Document Server

    Lutz, Jean Robert; Baudot, J; Bonnet, D; Coffin, J P; Germain, M; Gojak, C; Jundt, F; Kühn, C E; Suire, C; Tarchini, A; Berst, D; Clauss, G; Colledani, C; Dulinski, W; Boucham, A; Bouvier, S; Castillo, J; Drancourt, C; Erazmus, B; Guilloux, G; Martin, L; Roy, C

    1999-01-01

    Presentation made at LEB99, 20-24 September 1999A novel compact detector module has been produced by the "IReS"-"Subatech"-"Thomson-CSF-Detexis" collaboration. It includes a Double-Sided (DS) Silicon Strip Detector (SSD) and the related Front End Electronics (FEE) located on two hybrids, one for the N side and one for the P side. Bumpless Tape Automated Bonding (TAB) is used to connect the detector to the hybrids by means of microcables with neither wirebonding nor pitch adapter. Each of the six dedicated ALICE128C FE chip [1], located on the hybrid, is TABed on identical single layer microcables, which connect its inputs to the DS SSD and its outputs to the hybrid [2]. These microcables are bent in order to fold over the two hybrids on the DS SSD. This module meets the specifications of two experiments, ALICE (A Large Ion Collider Experiment) on the LHC accelerator at CERN [3] and STAR (Solenoid Tracker At Rhic) on the RHIC accelerator at BNL (Brookhaven National Laboratory)[4]. It can be used with air cooli...

  13. Integrated CubeSat ADACS with Reaction Wheels and Star Tracker Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A high performance ADACS (Attitude Determination and Control System) for CubeSats incorporating Miniature Star Trackers is proposed. The proposed program will focus...

  14. Ultra-Miniaturized Star Tracker for Small Satellite Attitude Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Creare and Virginia Polytechnic Institute and State University propose to design, develop, test, and deliver an ultra compact star tracker specifically intended for...

  15. Ultra-Miniaturized Star Tracker for Small Satellite Attitude Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Creare and Embry-Riddle Aeronautical University (ERAU) propose to complete the design, development, and testing of an ultra compact star tracker specifically...

  16. Spacecraft attitude control systems with dynamic methods and structures for processing star tracker signals

    Science.gov (United States)

    Liu, Yong (Inventor); Wu, Yeong-Wei Andy (Inventor); Li, Rongsheng (Inventor)

    2001-01-01

    Methods are provided for dynamically processing successively-generated star tracker data frames and associated valid flags to generate processed star tracker signals that have reduced noise and a probability greater than a selected probability P.sub.slctd of being valid. These methods maintain accurate spacecraft attitude control in the presence of spurious inputs (e.g., impinging protons) that corrupt collected charges in spacecraft star trackers. The methods of the invention enhance the probability of generating valid star tracker signals because they respond to a current frame probability P.sub.frm by dynamically selecting the largest valid frame combination whose combination probability P.sub.cmb satisfies a selected probability P.sub.slctd. Noise is thus reduced while the probability of finding a valid frame combination is enhanced. Spacecraft structures are also provided for practicing the methods of the invention.

  17. The Things You Can’t Ignore: Evolving a Sub-Arcsecond Star Tracker

    OpenAIRE

    Enright, John; Sinclair, Doug; Dzamba, Tom

    2012-01-01

    The feasibility of a star tracker with 1 arc-second accuracy and 1 deg/sec slew capability is explored, using the ST-16 design as a starting point. Whole-sky simulation is used to determine the impact of optical design on the star tracker availability. The current optical calibration process is examined, and shown to be inadequate for the desired performance. Additional factors that become important at high accuracy are examined. These are detector calibration, temperature variation, chromati...

  18. Development of a low cost star tracker for the SHEFEX mission

    OpenAIRE

    Samaan, Malak; Theil, Stephan

    2011-01-01

    German Aerospace Center (DLR) is designing and developing a novel star tracker to be used as the primary attitude sensor for the SHEFEX mission. The developed star tracker is considered to be a low cost and low accuracy sensor that is suitable for the proposed mission and the attitude accuracy requirements. This sensor is based on an off-the-shelf camera and a PC/104 computer communicating with the navigation computer. The attitude determination software consists of a processing chain incl...

  19. TRACKER

    CERN Multimedia

    Bora Akgun

    2013-01-01

    Pixel Tracker Maintenance of the Pixel Tracker has been ongoing since it was extracted from inside CMS and safely stored at low temperatures in Pixel laboratory at Point 5 (see previous Bulletin).    All four half cylinders of the forward Pixel detector (FPIX) have been repaired and the failures have been understood. In October, a team of technicians from Fermilab replaced a total of three panels that were not repairable in place. The replacement of panels is a delicate operation that involves removing the half disks that hold the panels from the half cylinders, removing the damaged panels from the half disks, installing the new panels on the half disks, and finally putting the half disks back into the half cylinders and hooking up the cooling connections. The work was completed successfully. The same team also prepared the installation of the Phase 1 Pixel pilot blade system, installing a third half disk mechanics in the half cylinders; these half disks will host new Phase 1 P...

  20. TRACKER

    CERN Multimedia

    K. Gill

    2010-01-01

    The Tracker has continued to operate with excellent performance during this first period with 7 TeV collisions. Strips operations have been very smooth. The up-time during collisions was 98.5%, up to end of May, with a large fraction of the down-time coming during the planned fine-timing scan with early 7 TeV collisions. Pixels operations are also going very well, besides problems related to background beam-gas collisions where the particles produced generate very large clusters in the barrel modules. When CMS triggers on these events, the FEDs affected overflow and then timeout. Effort was mobilised very quickly to understand and mitigate this problem, with modifications made to the pixel FED firmware in order to provide automatic recovery. With operations becoming more and more routine at P5, Pixels have begun the transition to centrally attended operation, which means that the P5 shifters will no longer be required to be on duty. The strip-Tracker is also planning to make this transition at the end of Ju...

  1. TRACKER

    CERN Multimedia

    K. Gill and G. Bolla

    2010-01-01

    Silicon strips During the first collisions the strip-Tracker operated with excellent performance and stability. The results obtained were very impressive and this exciting experience marked a fine end to another intense year. Several issues were identified during 2009 operations that could benefit from improvement: to suppress the increased output data volume when in STANDBY state (LV ON, HV OFF), which is due to the larger noise amplitudes when the sensors are unbiased; to reduce the strips configuration time; to increase the stability of the power system, particularly during state transitions, and to decrease the powering up time. The strip-Tracker FEDs now react to changes in the HV conditions of the strips. Upon a transition to STAND-BY, central DAQ starts a PAUSE-RESUME cycle and a flag is issued to the FEDSupervisor. This results in forcing the common mode noise artificially to the maximum value, which effectively suppresses the analogue data output. This forced offset is removed as soon as the strips ...

  2. Optical system error analysis and calibration method of high-accuracy star trackers.

    Science.gov (United States)

    Sun, Ting; Xing, Fei; You, Zheng

    2013-01-01

    The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers. PMID:23567527

  3. Optical System Error Analysis and Calibration Method of High-Accuracy Star Trackers

    Directory of Open Access Journals (Sweden)

    Zheng You

    2013-04-01

    Full Text Available The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers.

  4. Precision Attitude Determination System (PADS) design and analysis. Two-axis gimbal star tracker

    Science.gov (United States)

    1973-01-01

    Development of the Precision Attitude Determination System (PADS) focused chiefly on the two-axis gimballed star tracker and electronics design improved from that of Precision Pointing Control System (PPCS), and application of the improved tracker for PADS at geosynchronous altitude. System design, system analysis, software design, and hardware design activities are reported. The system design encompasses the PADS configuration, system performance characteristics, component design summaries, and interface considerations. The PADS design and performance analysis includes error analysis, performance analysis via attitude determination simulation, and star tracker servo design analysis. The design of the star tracker and electronics are discussed. Sensor electronics schematics are included. A detailed characterization of the application software algorithms and computer requirements is provided.

  5. An accuracy measurement method for star trackers based on direct astronomic observation.

    Science.gov (United States)

    Sun, Ting; Xing, Fei; Wang, Xiaochu; You, Zheng; Chu, Daping

    2016-01-01

    Star tracker is one of the most promising optical attitude measurement devices and it is widely used in spacecraft for its high accuracy. However, how to realize and verify such an accuracy remains a crucial but unsolved issue until now. The authenticity of the accuracy measurement method of a star tracker will eventually determine the satellite performance. A new and robust accuracy measurement method for a star tracker based on the direct astronomical observation is proposed here. In comparison with the conventional method with simulated stars, this method utilizes real navigation stars as observation targets which makes the measurement results more authoritative and authentic. Transformations between different coordinate systems are conducted on the account of the precision movements of the Earth, and the error curves of directional vectors are obtained along the three axes. Based on error analysis and accuracy definitions, a three-axis accuracy evaluation criterion has been proposed in this paper, which could determine pointing and rolling accuracy of a star tracker directly. Experimental measurements confirm that this method is effective and convenient to implement. Such a measurement environment is close to the in-orbit conditions and it can satisfy the stringent requirement for high-accuracy star trackers. PMID:26948412

  6. An accuracy measurement method for star trackers based on direct astronomic observation

    Science.gov (United States)

    Sun, Ting; Xing, Fei; Wang, Xiaochu; You, Zheng; Chu, Daping

    2016-03-01

    Star tracker is one of the most promising optical attitude measurement devices and it is widely used in spacecraft for its high accuracy. However, how to realize and verify such an accuracy remains a crucial but unsolved issue until now. The authenticity of the accuracy measurement method of a star tracker will eventually determine the satellite performance. A new and robust accuracy measurement method for a star tracker based on the direct astronomical observation is proposed here. In comparison with the conventional method with simulated stars, this method utilizes real navigation stars as observation targets which makes the measurement results more authoritative and authentic. Transformations between different coordinate systems are conducted on the account of the precision movements of the Earth, and the error curves of directional vectors are obtained along the three axes. Based on error analysis and accuracy definitions, a three-axis accuracy evaluation criterion has been proposed in this paper, which could determine pointing and rolling accuracy of a star tracker directly. Experimental measurements confirm that this method is effective and convenient to implement. Such a measurement environment is close to the in-orbit conditions and it can satisfy the stringent requirement for high-accuracy star trackers.

  7. TRACKER

    CERN Multimedia

    D. Duggan and L. Demaria

    2012-01-01

    Pixels Tracker With the 2012 proton-proton run almost complete, the pixel detector continues to operate well in an environment with large pile-up and high L1 rate. During this period, the pixel detector has shown excellent stability, with the number of current active channels from each the BPIX and FPIX the same as from the first month of 2012 running, resulting in 96.3% of the detector active. This total includes the recovery of six FPIX channels, temporarily disabled due to an unexpected dependence on the magnetic field. From a dedicated study that identified a small crack in an optical cable connector, a repair was made which restored 120 ROCs in the FPIX. During 2012 there has been a close collaboration of the online operations with the offline studies, resulting in the first dedicated HV bias scans used for the pixel Lorentz Angle measurement. These scans help to better understand this important parameter that changes with temperature, irradiation, and bias voltage. This is in addition to all other s...

  8. TRACKER

    CERN Multimedia

    M. Dinardo and G. Benelli

    2013-01-01

    Pixel Tracker At the beginning of May, the Pixel detector was successfully extracted from inside CMS. The operation lasted one and a half days each for the forward and barrel Pixel detectors. Everything went smoothly: new people were trained during the exercise and care was taken to minimise radiation exposure – see Image 3.  Lessons learned were noted in an updated written extraction procedure.  Care was also taken to prepare for reinsertion around the new beam pipe next year, with new alignment targets placed on the barrel Pixel detector. All pieces were lifted to the surface and are now safely stored at low temperatures in the dedicated Pixel laboratory at Point 5 (see Image 4 and previous Bulletin). Image 3 (a) and (b): Extracted FPIX and BPIX detector The subsequent maintenance of the forward Pixel detector started on 27 May.  Since then one of four half cylinders has been repaired and, even more importantly, most of the failures have been fully understood. ...

  9. TRACKER

    CERN Multimedia

    R. Yohay and E. Butz

    2013-01-01

      Pixel Tracker Preparation of the newly built Pixel clean room in the radioprotection (RP) zone of SX5 has been proceeding at a steady clip since the beginning of 2013. The clean room is designed to provide a cold, dry, dust-free laboratory environment for storage and repairs of the CMS Pixel detector during LS1 and future LHC shutdown periods. To that end, it is required to have robust temperature and humidity control, standalone DAQ and DCS systems, and space for specialised silicon testing and repair equipment. Good progress has been made in delivering each of these items. The ongoing project of commissioning the clean room HVAC system has been a success so far. The clean room will be kept at 10–20 Pa above atmospheric pressure to ensure that contaminants flow out of the room. There are two operating temperatures for the room: 21°C will be used when the Pixel detector components are under cold storage at subzero temperatures in well-sealed “cold boxes,” ...

  10. TRACKER

    CERN Multimedia

    E. Butz

    2011-01-01

    The strip tracker took data very efficiently during 2010 with system availabilities of above 97% in the pp running and close to 100% during the heavy-ion running. The number of active channels in the readout is largely stable around 98%. The maintenance and development during the extended technical stop have been focussed on improving the operating conditions of the main silicon strip cooling plants SS1 and SS2, which have been items of concern (see last Bulletin). In order to stabilise and smooth the operation of SS1 and SS2, larger bypass valves and variable frequency drivers (VFDs) have been introduced. Possible noise induced by operation of the VFDs on other parts of CMS has been evaluated and no increased noise has been reported so far. The leak rate of every single line on SS2 was measured with the precise test-rig. Besides the known leaky lines, ten other SS2 lines were measured to leak between 120 g/day and 1200 g/day under the given test conditions, establishin...

  11. Ground testing strategies for verifying the slew rate tolerance of star trackers.

    Science.gov (United States)

    Dzamba, Tom; Enright, John

    2014-01-01

    The performance of a star tracker is largely based on the availability of its attitude solution. Several methods exist to assess star tracker availability under both static and dynamic imaging conditions. However, these methods typically make various idealizations that can limit the accuracy of these results. This study aims to increase the fidelity of star tracker availability modeling by accounting for the effects of detection logic and pixel saturation on star detection. We achieve this by developing an analytical model for the focal plane intensity distribution of a star in the presence of sensor slew. Using the developed model, we examine the effects of slew rate on star detection using simulations and lab tests. The developed approach allows us to determine the maximum slew rate for which a star of a given stellar magnitude can still be detected. This information can then be used to describe the availability of a star tracker attitude solution as a function of slew rate, both spatially, across the entire celestial sphere, or locally, along a specified orientation track. PMID:24577522

  12. Ground Testing Strategies for Verifying the Slew Rate Tolerance of Star Trackers

    Directory of Open Access Journals (Sweden)

    Tom Dzamba

    2014-02-01

    Full Text Available The performance of a star tracker is largely based on the availability of its attitude solution. Several methods exist to assess star tracker availability under both static and dynamic imaging conditions. However, these methods typically make various idealizations that can limit the accuracy of these results. This study aims to increase the fidelity of star tracker availability modeling by accounting for the effects of detection logic and pixel saturation on star detection. We achieve this by developing an analytical model for the focal plane intensity distribution of a star in the presence of sensor slew. Using the developed model, we examine the effects of slew rate on star detection using simulations and lab tests. The developed approach allows us to determine the maximum slew rate for which a star of a given stellar magnitude can still be detected. This information can then be used to describe the availability of a star tracker attitude solution as a function of slew rate, both spatially, across the entire celestial sphere, or locally, along a specified orientation track.

  13. Determining the Requirements for the Star Tracker on JEM-EUSO

    OpenAIRE

    Dhraief, Youssef; Hedayati, Farid

    2015-01-01

    This work will focus on how the JEM-EUSO project, which orbits around Earth on the International Space Station and whose purpose is to detect air shower from the atmosphere caused by high energy particles from outer space, will be able to determine its positon once it detects such air shower. This is best done by adding a star tracker to it. The main purpose is to determine how accurate the star tracker has to be. To do this a few calculations were made, as well as looking for any star tracke...

  14. The STAR silicon vertex tracker: a large area silicon drift detector

    CERN Document Server

    Lynn, D; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pandey, S U; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R

    2000-01-01

    The Solenoidal Tracker At RHIC-Silicon Vertex Tracker (STAR-SVT) is a three barrel microvertex detector based upon silicon drift detector technology. As designed for the STAR-SVT, silicon drift detectors (SDDs) are capable of providing unambiguous two-dimensional hit position measurements with resolutions on the order of 20 mu m in each coordinate. Achievement of such resolutions, particularly in the drift direction coordinate, depends upon certain characteristics of silicon and drift detector geometry that are uniquely critical for silicon drift detectors hit measurements. Here we describe features of the design of the STAR-SVT SDDs and the front-end electronics that are motivated by such characteristics.

  15. The use of a second generation star tracker in the control loop of the pointing system

    DEFF Research Database (Denmark)

    Betto, Maurizio

    1998-01-01

    The scope of this note is to propose the use of a second generation star tracker to guide the UVISS pointing system.As UVISS is mounted on the International Space Station the time to observe a specific star is limited by the orbital motion, therefore it is crucial to reduce as much as possible the...... pointing and acquisition time.Due to the limited resources, primarily power and mass, and the attitude perturbations, the traditional pointing systems do not seem suitable.However, a star tracker of the second generation might be the key to find an elegant solution to the above points....

  16. In Orbit Performance of a Fully Autonomous Star Tracker

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    . The key features of the ASC are fast and extremely robust arcsecond accuracy in a miniature design. Due to the attractive ratios of performance to mass, power and cost, the ASC has been selected as the baseline attitude sensor for a suite of missions by the major space agencies of the world. Generally....... This paper compares in-orbit performance with ground test starting with a brief summary of the ASC configurations on the missions referenced, i.e. Teamsat, ASTRID2 and Oersted. Then the in-orbit operation and performance of the ASC with special emphasis on robustness and closed loop operation aspects...

  17. In Orbit Performance of a Fully Autonomous Star Tracker

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    . The key features of the ASC are fast and extremely robust arcsecond accuracy in a miniature design. Due to the attractive ratios of performance to mass, power and cost, the ASC has been selected as the baseline attitude sensor for a suite of missions by the major space agencies of the world. Generally...

  18. Operations of a non-stellar object tracker in space

    OpenAIRE

    Riis, Troels; Jørgensen, John Leif; Betto, Maurizio

    1999-01-01

    The ability to detect and track non-stellar objects by utilizing a star tracker may seem rather straight forward, as any bright object, not recognized as a star by the system is a non stellar object. However, several pitfalls and errors exist, if a reliable and robust detection is required. To test the operation, performance and robustness of such a function, the Autonomous Vision System (AVS), a fully autonomous star tracker that has flown onboard the Teamsat was equipped with several advanc...

  19. Star Tracker Attitude Estimation for an Indoor Ground-Based Spacecraft Simulator

    OpenAIRE

    Tappe, J.; Kim, J.J.; A. Jordan; Agrawal, B.N.

    2011-01-01

    The article of record as published may be found at http://dx.doi.org/10.2514/6.2011-6270 This paper presents a study of star tracker attitude estimation algorithms and implementation on an indoor ground-based Three Axis Spacecraft Simulator (TASS). Angle, Planar Triangle, and Spherical Triangle algorithms are studied for star pattern recognition. Least squares, QUEST and TRIAD algorithms are studied for attitude determination. A star field image is suspended above TASS. The indoor laborato...

  20. Low-frequency Periodic Error Identification and Compensation for Star Tracker Attitude Measurement

    Institute of Scientific and Technical Information of China (English)

    WANG Jiongqi; XIONG Kai; ZHOU Haiyin

    2012-01-01

    The low-frequency periodic error of star tracker is one of the most critical problems for high-accuracy satellite attitude determination.In this paper an approach is proposed to identify and compensate the low-frequency periodic error for star tracker in attitude measurement.The analytical expression between the estimated gyro drift and the low-frequency periodic error of star tracker is derived firstly.And then the low-frequency periodic error,which can be expressed by Fourier series,is identified by the frequency spectrum of the estimated gyro drift according to the solution of the first step.Furthermore,the compensated model of the low-frequency periodic error is established based on the identified parameters to improve the attitude determination accuracy.Finally,promising simulated experimental results demonstrate the validity and effectiveness of the proposed method.The periodic error for attitude determination is eliminated basically and the estimation precision is improved greatly.

  1. Magnitude calibration of a fixed head star tracker using Astro-1 flight data

    Science.gov (United States)

    Rakoczy, John M.; West, Mark E.

    1992-01-01

    The Astro-1 UV astronomy mission was hampered by the failures of the automatic star acquisition procedure. The acquisition procedure depended on the Instrument Pointing Subsystem's Fixed Head Star Trackers (FHST) to acquire, track and identify guidestars of known visual magnitude. During the Astro-1 mission it was suspected that the star magnitudes measured by the FHST were much lower than predicted. A postflight investigation of the Astro-1 flight data confirmed and quantified this suspicion. Star magnitude calibration curves computed from the flight data depict the variance from the preflight calibration curves. These results are helping engineers to plan improvements to the acquisition procedure for the upcoming Astro-2 mission.

  2. Application of flight data to Space Shuttle CCD star tracker catalog design

    Science.gov (United States)

    Barry, Karen; Hindman, Mark; Yates, Russell

    1993-01-01

    The new Shuttle Solid-State Tracker (SSST) is an improved but transparent replacement for the analog version which has flown on every Shuttle mission. This paper will examine the data collected from four Shuttle flights to establish parameters for selection of acceptable navigation stars, and apply those parameters to establish a star catalog which will be sufficient to ensure the ability of the SSST to perform attitude updates while docked to the Space Station.

  3. The AeroAstro Fast-Angular-Rate Miniature Star Tracker: Algorithms and Simulation Results

    OpenAIRE

    Seng, Bill; Stafford, James; Zenick, Ray; Kennedy, Vickie

    2005-01-01

    AeroAstro’s Fast Angular Rate Miniature Star Tracker (FAR-MST) is an optical-based system that uses image processing of star fields viewed from the satellite to determine ephemeris information. The FAR-MST system offers solutions to several problems, including the determination of an initial position fix (the “lost-in-space” problem), determination of spacecraft attitude, and measurement of spacecraft rotational velocity – even at high angular rates. Low-cost, high-performance microsatellites...

  4. Prospects for observing pulsating red giants with the MONS Star Trackers

    CERN Document Server

    Bedding, T R

    2000-01-01

    K and M giants show variability on timescales from years down to days and possibly even hours. I discuss the contribution that can be made with high-precision photometry that will be obtained by the MONS Star Trackers. These include observations of flare-like events on Mira variables, and oscillation spectra for K giants and short-period M giants.

  5. Star tracker axis-to-sunlit earth horizon angle constraint evaluations for rendezvous operations

    Science.gov (United States)

    Hutchison, W. L.

    1975-01-01

    The results are presented of a study initiated to evaluate the star tracker axis-to-sunlit earth horizon angle constraint with respect to limitations imposed on the passive target rendezvous capability. The data presented include considerations for dispersions and sensor pointing capabilities and generalizations with respect to the uncertainties associated with the angle constraint available in practice.

  6. StarTracker: An Integrated, Web-based Clinical Search Engine

    OpenAIRE

    Gregg, William; Jirjis, Jim; Lorenzi, Nancy M.; Giuse, Dario

    2003-01-01

    This poster details the design and use of the StarTracker clinical search engine. This program is fully integrated within our electronic medical record system and allows users to enter simple rules that direct formatted searches of multiple legacy databases.

  7. Exploring the possibilities for star-tracker assisted calibration of the six individual GOCE accelerometers

    NARCIS (Netherlands)

    Visser, P.N.A.M.

    2008-01-01

    A method has been developed and tested for estimating calibration parameters for the six accelerometers on board the Gravity field and steady-state Ocean Circulation Explorer (GOCE) from star tracker observations. These six accelerometers are part of the gradiometer, which is the prime instrument on

  8. Design and Performance Evaluation of an Intelligent Star Tracker

    OpenAIRE

    Clark, Natalie

    2001-01-01

    Current state-of-the-art commercial star sensors typically weigh 15 pounds, attain 5 to 10 arcsecond accuracy, and use roughly 10 watts of power. Unfortunately, the current state-of-the-art commercial star sensors do not meet many of NASA’s “next-generation” spacecraft and instrument needs. Nor do they satisfy Air Force’s needs for micro/nano-satellite systems. In an effort to satisfy micro/nano satellite mission needs the Air Force Research Laboratory is developing an intelligent star Tracke...

  9. The Forward GEM Tracker of STAR at RHIC

    OpenAIRE

    Simon, F.; Balewski, J.; Fatemi, R.; Hasell, D.; Kelsey, J.; Majka, R.; Page, B.; Plesko, M.; Underwood, D.; Smirnov, N.; Sowinski, J.; Spinka, H.; Surrow, B.(Temple University, Philadelphia, PA, 19122, USA); Visser, G.

    2008-01-01

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is in the process of designing and constructing a forward tracking system based on triple GEM technology. This upgrade is necessary to give STAR the capability to reconstruct and identify the charge sign of W bosons over an extended rapidity range through their leptonic decay mode into an electron (positron) and a neutrino. This will allow a detailed study of the flavor-separated spin str...

  10. CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

    Science.gov (United States)

    Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

    1996-01-01

    The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

  11. Star tracker based attitude determination system for nanosatellites

    OpenAIRE

    Jané Abad, Jaume

    2015-01-01

    The aim of this project is to conceive, design, implement, test, qualify, operate, and validate a new high accuracy sensor based on a star sensor for the ADCS subsystem of the 3Cat-2 Mission. This system will implement the necessary algorithms for the star identification and attitude determination in a highly constrained in time, size, mass and power embedded environment. Test and qualification campaign shall be done both in controlled environment and field test. [ANGLÈS] Access to space i...

  12. General constraints on influential error sources for super-high accuracy star tracker

    CERN Document Server

    Zhang, J; Wang, L; Long, Y

    2015-01-01

    Though in-orbit calibration is adopted to reduce position error of individual star spot down to 0.02pixel on star tracker, little study has been conducted on the accuracy to what extent for some significant error sources which often leads to in-orbit correction inefficiency. This study presents the general theory and estimates of the minimum error constraints, including not only on position but also on intensity and scale of Gaussian shaped profile based on Cramer Rao Lower Bound(CRLB) theory. By imposing those constraints on motion, drift in focal length and so on, margins of in-flight error sources and the final accuracy of star tracker can be analytically determined before launch.

  13. Deep coupling of star tracker and MEMS-gyro data under highly dynamic and long exposure conditions

    International Nuclear Information System (INIS)

    Star trackers and gyroscopes are the two most widely used attitude measurement devices in spacecrafts. The star tracker is supposed to have the highest accuracy in stable conditions among different types of attitude measurement devices. In general, to detect faint stars and reduce the size of the star tracker, a method with long exposure time method is usually used. Thus, under dynamic conditions, smearing of the star image may appear and result in decreased accuracy or even failed extraction of the star spot. This may cause inaccuracies in attitude measurement. Gyros have relatively good dynamic performance and are usually used in combination with star trackers. However, current combination methods focus mainly on the data fusion of the output attitude data levels, which are inadequate for utilizing and processing internal blurred star image information. A method for tracking deep coupling stars and MEMS-gyro data is proposed in this work. The method achieves deep fusion at the star image level. First, dynamic star image processing is performed based on the angular velocity information of the MEMS-gyro. Signal-to-noise ratio (SNR) of the star spot could be improved, and extraction is achieved more effectively. Then, a prediction model for optimal estimation of the star spot position is obtained through the MEMS-gyro, and an extended Kalman filter is introduced. Meanwhile, the MEMS-gyro drift can be estimated and compensated though the proposed method. These enable the star tracker to achieve high star centroid determination accuracy under dynamic conditions. The MEMS-gyro drift can be corrected even when attitude data of the star tracker are unable to be solved and only one navigation star is captured in the field of view. Laboratory experiments were performed to verify the effectiveness of the proposed method and the whole system. (paper)

  14. Star Tracker Algorithms and a Low-Cost Attitude Determination and Control System for Space Missions

    OpenAIRE

    Delabie, Tjorven

    2016-01-01

    The attitude determination and control system determines and controls the orientation of the spacecraft. This system is crucial in the majority of space missions to e.g. point a camera to a star or direct an antenna to a ground station. Increasingly complex missions drive the need for higher accuracy, while the growing number of small spacecraft requires high robustness and low computational cost. This work focusses on the star tracker, a sensor that takes an image of the stars and compares i...

  15. Autonomous attitude estimation via star sensing and pattern recognition

    Science.gov (United States)

    Junkins, J. L.; Strikwerda, T. E.

    1979-01-01

    Results are reported on the development of an autonomous, onboard, near real time spacecraft attitude estimation technique. The approach uses CCD based star sensors to digitize relative star positions. Three microcomputers are envisioned, configured in parallel, to: (1) determine star image centroids and delete spurious images; (2) identify measured stars with stars in an onboard catalog and determine discrete attitude estimates; (3) integrate gyro rate measurements and determine optimal real time attitude estimates for use in the control system and for feedback to the star identification algorithm. Algorithms for the star identification are presented. The discrete attitude estimation algorithm recovers thermally varying interlock angles between two star sensors. The optimal state estimation process recovers rate gyro biases in addition to real time attitude estimates.

  16. Performance of the Star Tracker Lightshades on the Earth Observing Satellite (EOS) Aqua

    Science.gov (United States)

    Kenney, Thomas; Schroeder, Michael; Donnelly, Michael; McNally, Mark; Bauer, Frank H. (Technical Monitor)

    2003-01-01

    The TRW built EOS Aqua spacecraft uses two Ball Aerospace CT-602 star trackers to provide attitude updates to the 3-axis, zero momentum, controller. Two months prior to the scheduled launch of Aqua, Ball reported an error in the design of the star tracker lightshades. The lightshades, which had been designed specifically for the EOS Common spacecraft, were not expected to meet the stray light rejection requirements of the mission and thus impact the overall spacecraft pointing performance. What ensued was an effort to characterize the actual performance of the existing shade design, determine what could be done within the physical envelope available, and modify the hardware to meet requirements. Changes were made based on this review activity and Aqua was launched on May 4, 2002. To date the spacecraft is meeting all of its science pointing requirements. Reported here are the lightshade design predictions, test results, and the measured on orbit performance of these shades.

  17. Apollo Telescope Mount (ATM) gimballed star tracker. [developed for the Skylab program

    Science.gov (United States)

    Lana, J. D.

    1974-01-01

    Design and development of six gimballed star trackers for Skylab's Apollo Telescope Mount, which performed successfully on all three manned Skylab missions and accumulated a total usage time of approximately 3,500 hours, is described in terms of configurations, materials and construction, qualification testing, performance, and reliability characteristics. A brief program history and design changes incorporated during the life of the program are also discussed. Extensive drawings, block diagrams, and photographs are provided.

  18. Success by 1000 Improvements: Flight Qualification of the ST-16 Star Tracker

    OpenAIRE

    Dzamba, Tom; Enright, John; Sinclair, Doug; Amankwah, Kofi; Votel, Ronny; Jovanovic, Ilija; McVittie, Geoffrey

    2014-01-01

    The first launch of a pair of 90 gram Sinclair Interplanetary ST-16 star trackers was in November, 2013 on-board the Skybox Imaging SkySat-1 satellite. The sensor performance — as captured by the sensors’ availability, accuracy, and bad-match rate — fell significantly below expectations. This paper explores the flight qualification campaign undertaken by the sensor developers to bring the sensors back to their intended level of performance. No single fix was sufficient and many small incremen...

  19. Optical analysis of the star-tracker telescope for Gravity Probe

    Science.gov (United States)

    Zissa, D. E.

    1984-01-01

    A ray tracing modeling of the star tracker telescope for Gravity Probe was used to predict the character of the output signal and its sensitivity to fabrication errors. In particular, the impact of the optical subsystem on the requirement of 1 milliarc second signal linearity over a + or - 50 milliarc second range was examined. Photomultiplier and solid state detector options were considered. Recommendations are made.

  20. Exploring the possibilities for star-tracker assisted calibration of the six individual GOCE accelerometers

    OpenAIRE

    Visser, P N A M

    2008-01-01

    A method has been developed and tested for estimating calibration parameters for the six accelerometers on board the Gravity field and steady-state Ocean Circulation Explorer (GOCE) from star tracker observations. These six accelerometers are part of the gradiometer, which is the prime instrument on board GOCE. It will be shown that by taking appropriate combinations of observations collected by the accelerometers, by modeling acceleration terms caused by gravity gradients from an a priori lo...

  1. 新型分体式星敏感器设计及其应用%Design and applications of novel separated type star tracker

    Institute of Scientific and Technical Information of China (English)

    钟红军; 卢欣; 李春江; 李玉明; 李晓

    2014-01-01

    星敏感器是当前广泛应用于航天器姿态测量的高精度光学姿态敏感器。介绍了一种新型分体式星敏感器的总体设计、应用及验证情况,其已成功应用于科学试验、通讯及地球观测等多种卫星平台,共有21套产品在轨验证。根据在轨遥测数据分析,全面验证了其主要技术指标:探测灵敏度5.7 Mv、数据更新率8 Hz、测量精度2.6″、阳光抑制角28°、动态性能1(°)/s等。新型分体式星敏感器是国际上首个在轨飞行验证并引入控制系统闭环控制的APS星敏感器,根据地面测试验证结果和20余套产品长达两年在轨数据的全面分析,其在轨性能与地面测试性能一致,在轨测试结果证明产品的测量精度、鲁棒性、可用性和可靠性等主要性能满足卫星使用要求。%Star tracker is current widely used optical sensor in spacecraft attitude control system which produces the most accurate measurements. The overall design description, application and qualification results of a novel separated autonomous miniature star tracker were introduced. The novel separated type star tracker successfully operated in-orbit on a large variety of different satellite platforms such as scientific experiment, telecommunication and earth observation. The novel star tracker has applied in-orbit with a total of 21 sets of products up to now. According to the real time telemetry data packages under real in-orbit conditions, the main qualification features are sensitivity 5.7 Mv, update rate 8 Hz, accuracy 2.6″, sun exclusion 28° , tracking slew rate 1 (° )/s. The novel separated type star tracker was the first APS based star tracker ever flown which was adopted in AOCS closed loop control. A full analysis on ground qualification campaign was carried out successfully on the novel star tracker and an in-flight qualification was also achieved, with more than two years information from 20 other star trackers on

  2. Triple GEM Detectors for the Forward Tracker in STAR

    CERN Document Server

    Simon, Frank; Kohl, Michael; Majka, Richard; Plesko, Miroslav; Underwood, David; Sakuma, Tai; Smirnov, Nikolai; Spinka, Harold; Surrow, Bernd

    2007-01-01

    Future measurements of the flavor-separated spin structure of the proton via parity-violating W boson production at RHIC require an upgrade of the forward tracking system of the STAR detector. This upgrade will allow the reconstruction of the charge sign of electrons and positrons produced from decaying W bosons. A design based on six large area triple GEM disks using GEM foils produced by Tech-Etch Inc. has emerged as a cost-effective solution to provide the necessary tracking precision. We report first results from a beam test of three test detectors using Tech-Etch produced GEM foils and a laser etched two dimensional strip readout. The detectors show good operational stability, high efficiency and a spacial resolution of around 70 um or better, exceeding the requirements for the forward tracking upgrade. The influence of the angle of incidence of the particles on the spatial resolution of the detectors has also been studied in detail.

  3. Reducing systematic centroid errors induced by fiber optic faceplates in intensified high-accuracy star trackers.

    Science.gov (United States)

    Xiong, Kun; Jiang, Jie

    2015-01-01

    Compared with traditional star trackers, intensified high-accuracy star trackers equipped with an image intensifier exhibit overwhelmingly superior dynamic performance. However, the multiple-fiber-optic faceplate structure in the image intensifier complicates the optoelectronic detecting system of star trackers and may cause considerable systematic centroid errors and poor attitude accuracy. All the sources of systematic centroid errors related to fiber optic faceplates (FOFPs) throughout the detection process of the optoelectronic system were analyzed. Based on the general expression of the systematic centroid error deduced in the frequency domain and the FOFP modulation transfer function, an accurate expression that described the systematic centroid error of FOFPs was obtained. Furthermore, reduction of the systematic error between the optical lens and the input FOFP of the intensifier, the one among multiple FOFPs and the one between the output FOFP of the intensifier and the imaging chip of the detecting system were discussed. Two important parametric constraints were acquired from the analysis. The correctness of the analysis on the optoelectronic detecting system was demonstrated through simulation and experiment. PMID:26016920

  4. Reducing Systematic Centroid Errors Induced by Fiber Optic Faceplates in Intensified High-Accuracy Star Trackers

    Directory of Open Access Journals (Sweden)

    Kun Xiong

    2015-05-01

    Full Text Available Compared with traditional star trackers, intensified high-accuracy star trackers equipped with an image intensifier exhibit overwhelmingly superior dynamic performance. However, the multiple-fiber-optic faceplate structure in the image intensifier complicates the optoelectronic detecting system of star trackers and may cause considerable systematic centroid errors and poor attitude accuracy. All the sources of systematic centroid errors related to fiber optic faceplates (FOFPs throughout the detection process of the optoelectronic system were analyzed. Based on the general expression of the systematic centroid error deduced in the frequency domain and the FOFP modulation transfer function, an accurate expression that described the systematic centroid error of FOFPs was obtained. Furthermore, reduction of the systematic error between the optical lens and the input FOFP of the intensifier, the one among multiple FOFPs and the one between the output FOFP of the intensifier and the imaging chip of the detecting system were discussed. Two important parametric constraints were acquired from the analysis. The correctness of the analysis on the optoelectronic detecting system was demonstrated through simulation and experiment.

  5. General constraints on influential error sources for super-high accuracy star tracker

    OpenAIRE

    Zhang, J.; Hao, Y. C.; Wang, L.; Long, Y

    2015-01-01

    Though in-orbit calibration is adopted to reduce position error of individual star spot down to 0.02pixel on star tracker, little study has been conducted on the accuracy to what extent for some significant error sources which often leads to in-orbit correction inefficiency. This study presents the general theory and estimates of the minimum error constraints, including not only on position but also on intensity and scale of Gaussian shaped profile based on Cramer Rao Lower Bound(CRLB) theory...

  6. Fixed-head star tracker attitude updates on the Hubble Space Telescope

    Science.gov (United States)

    Nadelman, Matthew S.; Karl, Jeffrey B.; Hallock, Lou

    1994-01-01

    The Hubble Space Telescope (HST) was launched in April 1990 to begin observing celestial space to the edge of the universe. National Aeronautics and Space Administration (NASA) standard fixed-head star trackers (FHST's) are used operationally onboard the HST to regularly adjust ('update') the spacecraft attitude before the acquisition of guide stars for science observations. During the first 3 months of the mission, the FHST's updated the spacecraft attitude successfully only 85 percent of the time. During the other periods, the trackers were unable to find the selected stars -- either they failed to find any star, or worse, they selected incorrect stars and produced erroneous attitude updates. In July 1990, the HST project office at Goddard Space Flight Center (GSFC) requested that Computer Sciences Corporation (CSC) form an investigative 'tiger' team to examine these FHST update failures. This paper discusses the work of the FHST tiger team, describes the investigations that led the team to identify the sources of the errors, and defines the solutions that were subsequently developed, which ultimately increased the success rate of FHST updates to approximately 98 percent.

  7. Simple free star-autonomous categories and full coherence

    OpenAIRE

    Hughes, Dominic

    2005-01-01

    This paper gives a simple presentation of the free star-autonomous category over a category, based on Eilenberg-Kelly-MacLane graphs and Trimble rewiring, yielding a full coherence theorem: the commutativity of diagrams of canonical maps is decidable.

  8. (abstract) Realization of a Faster, Cheaper, Better Mission and Its New Paradigm Star Tracker, the Advanced Stellar Compass

    Science.gov (United States)

    Eisenman, Allan Read; Liebe, Carl Christian; Joergensen, John Lief; Jensen, Gunnar Bent

    1997-01-01

    The first Danish satellite, rsted, will be launched in August of 1997. The scientific objective of sted is to perform a precision mapping of the Earth's magnetic field. Attitude data for the payload and the satellite are provided by the Advanced Stellar Compass (ASC) star tracker. The ASC consists of a CCD star camera and a capable microprocessor which operates by comparing the star image frames taken by the camera to its internal star catalogs.

  9. Fixed-head star tracker magnitude calibration on the solar maximum mission

    Science.gov (United States)

    Pitone, Daniel S.; Twambly, B. J.; Eudell, A. H.; Roberts, D. A.

    1990-01-01

    The sensitivity of the fixed-head star trackers (FHSTs) on the Solar Maximum Mission (SMM) is defined as the accuracy of the electronic response to the magnitude of a star in the sensor field-of-view, which is measured as intensity in volts. To identify stars during attitude determination and control processes, a transformation equation is required to convert from star intensity in volts to units of magnitude and vice versa. To maintain high accuracy standards, this transformation is calibrated frequently. A sensitivity index is defined as the observed intensity in volts divided by the predicted intensity in volts; thus, the sensitivity index is a measure of the accuracy of the calibration. Using the sensitivity index, analysis is presented that compares the strengths and weaknesses of two possible transformation equations. The effect on the transformation equations of variables, such as position in the sensor field-of-view, star color, and star magnitude, is investigated. In addition, results are given that evaluate the aging process of each sensor. The results in this work can be used by future missions as an aid to employing data from star cameras as effectively as possible.

  10. A high-accuracy digital star tracker for advanced planetary missions

    Science.gov (United States)

    Salomon, P. M.; Crawford, W. E.

    1973-01-01

    The digital star tracker represents a novel departure from previous analog designs in terms of circuit implementation and operational capabilities. As an element of an all-digital spacecraft control system, it combines proven low-level analog signal processing with digital error control and command functions. Additional capabilities that are obtainable with the digital circuitry include programmable intensity threshold gates, commanded electronic pointing control, and an acquisition/control algorithm which minimizes the effects of straylight disturbances. The capabilities inherent in the implementation have been successfully demonstrated in a laboratory model of the instrument.

  11. LLiST - a new star tracker camera for tip-tilt correction at IOTA

    OpenAIRE

    Schuller, P.A.; Lacasse, M. G.; Lydon, D.; McGonagle, W. H.; Pedretti, E; Reich, R. K.; Schloerb, F. P.; Traub, W. A.

    2004-01-01

    The tip-tilt correction system at the Infrared Optical Telescope Array (IOTA) has been upgraded with a new star tracker camera. The camera features a backside-illuminated CCD chip offering doubled overall quantum efficiency and a four times higher system gain compared to the previous system. Tests carried out to characterize the new system showed a higher system gain with a lower read-out noise electron level. Shorter read-out cycle times now allow to compensate tip-tilt fluctuations so that ...

  12. STR: a student developed star tracker for the ESA-LED ESMO moon mission

    OpenAIRE

    Lizy-Destrez, Stéphanie; Mimoun, David

    2010-01-01

    In the frame of their engineering degree, ISAE’s students are developing a Star Tracker, with the aim of being the core attitude estimation equipment of the European Moon Student Orbiter. This development goes on since several years and is currently in phase B. We intend to start building an integrated breadboard for the end of the academic year. The STR is composed of several sub-systems: the optical and detection sub-system, the electronics, the mechanics and the software. The optical de...

  13. LLiST - a new star tracker camera for tip-tilt correction at IOTA

    CERN Document Server

    Schuller, P A; Lydon, D; McGonagle, W H; Pedretti, E; Reich, R K; Schloerb, F P; Traub, W A

    2004-01-01

    The tip-tilt correction system at the Infrared Optical Telescope Array (IOTA) has been upgraded with a new star tracker camera. The camera features a backside-illuminated CCD chip offering doubled overall quantum efficiency and a four times higher system gain compared to the previous system. Tests carried out to characterize the new system showed a higher system gain with a lower read-out noise electron level. Shorter read-out cycle times now allow to compensate tip-tilt fluctuations so that their error imposed on visibility measurements becomes comparable to, and even smaller than, that of higher-order aberrations.

  14. Development of the Pico Star Tracker ST-200 – Design Challenges and Road Ahead

    OpenAIRE

    Segert, Tom; Engelen, Steven; Buhl, Matthias; Monna, Bert

    2011-01-01

    The Pico Star Tracker ST-200 under development by Berlin Space Technologies GmbH (BST) is specifically designed keeping the limitations of CubeSats in mind. It comes in a compact 29x29x37mm³ package. It weights 74g and has a power consumption of 220mW average (620mW peak). The ST-200 offers a set of standard interfaces (I²C, SPI, RS485, RS232) and accepts input voltages of 3.3 to 5V. It can detect stars with a limiting magnitude of 6 and has an accuracy of 30 arc seconds (~0.01°). Using its i...

  15. Operations of a non-stellar object tracker in space

    DEFF Research Database (Denmark)

    Riis, Troels; Jørgensen, John Leif; Betto, Maurizio

    1999-01-01

    The ability to detect and track non-stellar objects by utilizing a star tracker may seem rather straight forward, as any bright object, not recognized as a star by the system is a non stellar object. However, several pitfalls and errors exist, if a reliable and robust detection is required. To test...... the operation, performance and robustness of such a function, the Autonomous Vision System (AVS), a fully autonomous star tracker that has flown onboard the Teamsat was equipped with several advanced features. These features included a non-stellar object detection and tracking module and an image and...

  16. Theoretic Studies of Full Constraints on a Star Tracker's Influential Error Sources for In-orbit Calibration

    Science.gov (United States)

    Zhang, Jun; Cai Hao, Yun; Wang, Li; Long, Ye

    2016-03-01

    To collect star transits data qualified for in-orbit calibration, this study derives the full error constraints to limit star tracker's influential error sources and computes their error boundaries from a theoretical perspective. The full constraints, including not only the minimum variance estimation of position but also the error bound prediction of scale and intensity of Gaussian-shaped starspots, are studied based on the Cramér-Rao Lower Bound (CRLB) theorem. By imposing these constraints on motion, drift in focal length, and other factors, their boundaries could be determined before launch. Therefore, the in-orbit correction accuracy is expected to be close to CRLB through suitable implementation of these constraints. The correctness of the theoretical position error of motion is demonstrated by the data-fitting procedure against test results of star tracker on dynamic performance. The simulation result shows that the drift in focal length can generate an error with the same magnitude as detector noise and thus might be the dominant error source when star tracker is working under stationary circumstance. Using the accuracy performance of some typical star trackers, this study shows that the CRLB constraint may be very effective to estimate the overall position error of a starspot or one axis, valuable data that can be used for online calibration. The overall position uncertainty analysis shows that a weighted method can be employed for calibration, a process where star data can be given a weight in inverse proportion to the CRLB value.

  17. Color/magnitude calibration for National Aeronautics and Space Administration (NASA) standard Fixed-Head Star Trackers (FHST)

    Science.gov (United States)

    Landis, J.; Leid, Terry; Garber, A.; Lee, M.

    1994-01-01

    This paper characterizes and analyzes the spectral response of Ball Aerospace fixed-head star trackers, (FHST's) currently in use on some three-axis stabilized spacecraft. The FHST output is a function of the frequency and intensity of the incident light and the position of the star image in the field of view. The FHST's on board the Extreme Ultraviolet Explorer (EUVE) have had occasional problems identifying stars with a high B-V value. These problems are characterized by inaccurate intensity counts observed by the tracker. The inaccuracies are due to errors in the observed star magnitude values. These errors are unique to each individual FHST. For this reason, data were also collected and analyzed from the Upper Atmosphere Research Satellite (UARS). As a consequence of this work, the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) hopes to improve the attitude accuracy on these missions and to adopt better star selection procedures for catalogs.

  18. Status and Physics Opportunities of the STAR Heavy Flavor Tracker and the Muon Telescope Detector Upgrades

    International Nuclear Information System (INIS)

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. HFT utilizes the state-of-art active pixel detector technology, which will greatly enhance the STAR physics capabilities by measuring heavy quark yield, collectivity and correlations via the topological reconstruction of charmed hadrons over a wide momentum range. The MTD is based on the long Multi-Gap Resistive Plate Chamber detector technology designed to measure muons penetrating the bulk of other detectors and the magnet yoke. It will enable STAR to study di-muon and electron-muon correlations and enhance heavy quarkonium studies. With the addition of these upgrades, STAR is well suited to perform precise measurements of production as well as correlations of rare probes (heavy flavors, dileptons) to systematically investigate the quark-gluon plasma properties at RHIC. For Run 13 63% of the MTD has been installed and data have been taken. Prototype PXL sectors (30% coverage) have also been installed and commissioned. Anticipated physics results and current status of these upgrades is reported

  19. Status and Physics Opportunities of the STAR Heavy Flavor Tracker and the Muon Telescope Detector Upgrades

    Science.gov (United States)

    Hao, Qiu; Star Collaboration

    2014-05-01

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. HFT utilizes the state-of-art active pixel detector technology, which will greatly enhance the STAR physics capabilities by measuring heavy quark yield, collectivity and correlations via the topological reconstruction of charmed hadrons over a wide momentum range. The MTD is based on the long Multi-Gap Resistive Plate Chamber detector technology designed to measure muons penetrating the bulk of other detectors and the magnet yoke. It will enable STAR to study di-muon and electron-muon correlations and enhance heavy quarkonium studies. With the addition of these upgrades, STAR is well suited to perform precise measurements of production as well as correlations of rare probes (heavy flavors, dileptons) to systematically investigate the quark-gluon plasma properties at RHIC. For Run 13 63% of the MTD has been installed and data have been taken. Prototype PXL sectors (30% coverage) have also been installed and commissioned. Anticipated physics results and current status of these upgrades is reported.

  20. Studies on dynamic motion compensation and positioning accuracy on star tracker.

    Science.gov (United States)

    Jun, Zhang; Yuncai, Hao; Li, Wang; Da, Liu

    2015-10-01

    Error from motion is the dominant restriction on the improvement of dynamic performance on a star tracker. As a remarkable motion error, the degree of nonuniformity of the star image velocity field on the detector is studied, and thus a general model for the moving star spot is built. To minimize velocity nonuniformity, a novel general method is proposed to derive the proper motion compensation and location accuracy in cases of both uniform velocity and acceleration. Using this method, a theoretic analysis on the accuracy of time-delayed integration and similar techniques, which are thought of as state-of-the-art approaches to reduce error from motion, is conducted. The simulations and experimental results validate the proposed method. Our method shows a more steady performance than the dynamic binning algorithm. The positional error could be neglected when the smear length is far less than 3.464 times the scale of star spot, which suggests accuracy can be maintained by changing frame-integration time inverse proportional to the velocity on the focal plane. It also shows that the acceleration effect must be compensated to achieve accuracy close to the Cramér-Rao lower bound. PMID:26479618

  1. Secure Transportable Autonomous Reactor (STAR-H2). Annex XXIV

    International Nuclear Information System (INIS)

    STAR1 concept development is being conducted for a portfolio of reactor and balance of plant designs to enable an incremental market penetration that is time-phased according to the degree of R and D required. Secure Transportable Autonomous Reactor - Liquid Metal (STAR-LM) is a Pb-cooled, 400 MW(th), natural circulation reactor of 565 deg. C core outlet temperature driving a supercritical CO2 Brayton cycle for electricity production. It draws on many proven technologies and will be ready for market in 15-20 years. The STAR-H2 raises the Pb outlet temperature to 800 deg. C to drive a thermochemical water cracking cycle and will require additional R and D. It is targeted for deployment by 2030. The SSTAR takes the STAR-LM design features down to ∼ 25 to 50 MW(th) to provide for secure energy supply to remote small villages. It is targeted for early prototyping of the technology and institutional features of the STAR concept. All STAR concepts are designed for 15 to 20-year refuelling interval and rely on outsourcing the associated fuel cycle and waste management services to proposed regional fuel cycle centres. All employ desalination (or alterative) bottoming cycles to extend their scope of energy services and to minimize their environmental footprint. The small sizing and outsourced fuel cycle and waste management configuration allows for plant deployment at modest initial capital outlay by the customer. Turnkey plants are transported to the customer's site and rapidly connected to a pre-constructed non-nuclear safety grade balance of plant to achieve a rapid start of the revenue stream. The R and D for the STAR-H2 concept is being performed in Argonne National Laboratory (ANL, USA). Institutions involved in STAR-H2 research and development together with ANL are Oregon State University, Texas A and M University, and Ohio State University

  2. Simulation on the Charged Particle Response of the STAR Heavy Flavor Tracker Pixel Detector

    Science.gov (United States)

    Cimaroli, Alex; Li, Xin

    2009-10-01

    The main task of the STAR experiment, located at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory, is to study the quark-gluon plasma (QGP), which is believed to have been created a few microseconds after the ``Big Bang.'' Heavy quarks are ideal tools for studying the properties of QGP. The Heavy Flavor Tracker (HFT) is the central part of the STAR future heavy flavor physics program and will enable STAR to directly measure heavy flavor mesons. The core of HFT is a pixel detector (PIXEL) using CMOS Active PIXEL Sensor. This poster will describe the development of a detailed simulation of the pixel detector response to charged particles and the corresponding fast simulation that dramatically enhances the simulation speed with little sacrifice in accuracy. The full simulation randomly generates ionized electrons along an incoming track and diffuses the electrons inside the pixel array until they are collected by the electronics or recombined inside a pixel. With the same result, the fast simulation, which quickens processing time from one hour to 5 seconds, generates a grid inside a single pixel and create a map of probability distribution functions for a single ionized electron generated from a grid point. We will also discuss the study of pixel detector position resolution using a simple clustering algorithm.

  3. Test of charge injection device, phase 1. [prospective star tracker application

    Science.gov (United States)

    Gradinger, A.; Sayles, M. B.; Peters, D.; Buckley, P.

    1981-01-01

    A computer-controlled automatic facility containing two interactive microprocessors, peripherals, and an optical bench was used to obtain device characteristics for use in evaluating CID's as the sensor element in a prospective star tracker application. Each of the ST-256 chips tested contains a 256 x 256 pixel element array with 65536 picture elements. Two ST-256 devices were tested at 20 C under light levels of 10%, 0.1%, and 0.01% saturation, and in darkness. The saturation level was established at 0.95 microwatts sq cm as measured by the radiometeric sensor. Two test runs under each condition were performed for each chip. Two complete sets of data for each of the devices were thus obtained. A separate data field was used to store the results of each test condition. Repetitive runs of a test condition were stored sequentially in the same file. Examination of the data using print-outs is shown in examples.

  4. Analysis for Mar Vel Black and acetylene soot low reflectivity surfaces for star tracker sunshade applications

    Science.gov (United States)

    Yung, E.

    1974-01-01

    Mar Vel Black is a revolutionary new extremely low reflectivity anodized coating developed by Martin Marietta of Denver. It is of great interest in optics in general, and in star trackers specifically because it can reduce extraneous light reflections. A sample of Mar Vel Black was evaluated. Mar Vel Black looks much like a super black surface with many small peaks and very steep sides so that any light incident upon the surface will tend to reflect many times before exiting that surface. Even a high reflectivity surface would thus appear to have a very low reflectivity under such conditions. Conversely, acetylene soot does not have the magnified surface appearance of a super black surface. Its performance is, however, predictable from the surface structure, considering the known configuration of virtually pure carbon.

  5. A study of a multi-pinned phase CCD detector for use as a star tracker

    Science.gov (United States)

    Friedman, Scott D.

    1994-01-01

    This grant has supported studies of the use of charge coupled devices (CCD's) in star trackers in a number of different areas. Among the tasks we have pursued are the following: (1) radiation modeling and the increase in noise equivalent angle as a result of exposure to protons and bremsstrahlung gamma rays; (2) the development of pattern matching software to identify field locations from a CCD image and a pre-existing map of the local area; (3) observations of various stellar fields from the 24 inch telescope at the Offit Observatory at JHU, primarily to test the pattern matching software (these included crowded fields as well as moving objects, like comets); and (4) tracking of very faint objects to determine the faint limit of the CCD system.

  6. Star tracker constraint violations digital capability description and analysis results. Mission planning, mission analysis, and software formulation

    Science.gov (United States)

    Poston, P. L.

    1975-01-01

    Results of star tracker constraint violation analyses performed with the digital computer program Shuttle Attitude and Pointing Time Line Processor (SAPT) are presented. Results are typical of those utilized to provide the information required to update Baseline Reference Mission Attitude and Pointing Time Lines. Descriptions of SAPT modifications implemented to perform these analyses are also presented.

  7. XpertTrack: Precision Autonomous Measuring Device Developed for Real Time Shipments Tracker.

    Science.gov (United States)

    Viman, Liviu; Daraban, Mihai; Fizesan, Raul; Iuonas, Mircea

    2016-01-01

    This paper proposes a software and hardware solution for real time condition monitoring applications. The proposed device, called XpertTrack, exchanges data through the GPRS protocol over a GSM network and monitories temperature and vibrations of critical merchandise during commercial shipments anywhere on the globe. Another feature of this real time tracker is to provide GPS and GSM positioning with a precision of 10 m or less. In order to interpret the condition of the merchandise, the data acquisition, analysis and visualization are done with 0.1 °C accuracy for the temperature sensor, and 10 levels of shock sensitivity for the acceleration sensor. In addition to this, the architecture allows increasing the number and the types of sensors, so that companies can use this flexible solution to monitor a large percentage of their fleet. PMID:26978360

  8. Star Tracker Based ATP System Conceptual Design and Pointing Accuracy Estimation

    Science.gov (United States)

    Orfiz, Gerardo G.; Lee, Shinhak

    2006-01-01

    A star tracker based beaconless (a.k.a. non-cooperative beacon) acquisition, tracking and pointing concept for precisely pointing an optical communication beam is presented as an innovative approach to extend the range of high bandwidth (> 100 Mbps) deep space optical communication links throughout the solar system and to remove the need for a ground based high power laser as a beacon source. The basic approach for executing the ATP functions involves the use of stars as the reference sources from which the attitude knowledge is obtained and combined with high bandwidth gyroscopes for propagating the pointing knowledge to the beam pointing mechanism. Details of the conceptual design are presented including selection of an orthogonal telescope configuration and the introduction of an optical metering scheme to reduce misalignment error. Also, estimates are presented that demonstrate that aiming of the communications beam to the Earth based receive terminal can be achieved with a total system pointing accuracy of better than 850 nanoradians (3 sigma) from anywhere in the solar system.

  9. An enhanced Cramér-Rao bound weighted method for attitude accuracy improvement of a star tracker

    Science.gov (United States)

    Zhang, Jun; Wang, Jian

    2016-06-01

    This study presents a non-average weighted method for the QUEST (QUaternion ESTimator) algorithm, using the inverse value of root sum square of Cramér-Rao bound and focal length drift errors of the tracking star as weight, to enhance the pointing accuracy of a star tracker. In this technique, the stars that are brighter, or at low angular rate, or located towards the center of star field will be given a higher weight in the attitude determination process, and thus, the accuracy is readily improved. Simulations and ground test results demonstrate that, compared to the average weighted method, it can reduce the attitude uncertainty by 10%-20%, which is confirmed particularly for the sky zones with non-uniform distribution of stars. Moreover, by using the iteratively weighted center of gravity algorithm as the newly centroiding method for the QUEST algorithm, the current attitude uncertainty can be further reduced to 44% with a negligible additional computing load.

  10. Heavy Flavor Physics in Heavy-Ion Collisions with STAR Heavy Flavor Tracker

    Science.gov (United States)

    Zhang, Yifei

    2010-02-01

    Heavy quarks are a unique tool to probe the strongly interacting matter created in relativistic heavy-ion collisions at RHIC energies. Due to their large mass, energetic heavy quarks are predicted to lose less energy than light quarks by gluon radiation when they traverse a Quark-Gluon Plasma. In contrast, recent measurements of non-photonic electrons from heavy quark decays at high transverse momentum (pT) show a jet quenching level similar to that of the light hadrons. Heavy quark are produced mainly at early stage in heavy-ion collisions, thus they are proposed to probe the QCD medium and to be sensitive to bulk medium properties. Ultimately, their flow behavior may help establish whether light quarks thermalize. Therefore, topological reconstruction of D-mesons and identification of electrons from charm and bottom decays are crucial to understand the heavy flavor production and their in medium properties. The Heavy Flavor Tracker (HFT) is a micro-vertex detector utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precise measurement of charmed and bottom hadrons. We present a performance study with full detector on the open charm nuclear modification factor, elliptic flow v2 and λc measurement as well as the measurement of bottom mesons via a semi-leptonic decay. )

  11. A method of autonomous orbit determination for satellite using star sensor

    Institute of Scientific and Technical Information of China (English)

    MA; Jianbo; XU; Jin

    2005-01-01

    In this paper a method of autonomous orbit determination using star sensor is studied. By building relatively consummate dynamical models which simulate attitude motion of satellite and observation from satellite to background stars, the simulant computation of this method is executed, and it is shown that the method of autonomous orbit determination is feasible. Academic and calculation analyses have been done for the relation between the direction of star sensor with respect to satellite-body coordinate system and the accuracy of autonomous orbit determination.

  12. Calibration of the Heavy Flavor Tracker (HFT) detector in star experiment at RHIC

    Science.gov (United States)

    Alanazi, Norah

    This project is in the area of Relativistic Nuclear collisions and the commissioning of a new silicon vertex detector, the Heavy Flavor Tracker (HFT) in the STAR experiment at Brookhaven National Laboratory (BNL). BNL hosts RHIC, the Relativistic Heavy Ion Collider, the world's most advanced dedicated heavy ion and polarized proton accelerator facility. Heavy Ion collisions at RHIC provide a unique probe into the understanding of several aspects of the behavior of nuclear, i.e. strongly inter- acting, matter. Among the many insights that can be provided is the description of parton interaction inside the hot and dense medium produced in the early stages of a collision. It also allows us to search for evidence for a phase transition in nuclear matter, a phase where partons [quarks and gluons] can move freely over an extended volume. Production of heavy quarks in high-energy nuclear collisions at RHIC occurs mainly during the initial collisions where energetic gluon and quark interactions can create heavy quarks. Thus, heavy flavor provides an ideal probe in studying the hot and dense medium created in the early phases of high-energy nuclear collisions. A detailed study of heavy flavor is essential to better understand the parton dynamics and select among competing theoretical approaches, however, precise measurements of heavy flavor are difficult to obtain due to relatively low production rates and short lifetimes of heavy flavor hadrons. The combinatorial background in nuclear collisions makes the measurement of heavy flavor a challenging task. One approach to dramatically reduce the combinatorial background by several orders of magnitude is to separate the heavy-flavor hadron's decay vertex from the background. This is done with the help of high resolution vertex detectors. The Heavy Flavor Tracker upgrade for the STAR experiment, which made its debut during the year 2014 RHIC run (Run14), greatly improved the experiment's track pointing capabilities making STAR

  13. Heavy Flavor Physics in Heavy-Ion Collisions with STAR Heavy Flavor Tracker

    International Nuclear Information System (INIS)

    Heavy quarks are a unique tool to probe the strongly interacting matter created in relativistic heavy-ion collisions at RHIC energies. Due to their large mass, energetic heavy quarks are predicted to lose less energy than light quarks by gluon radiation when they traverse a Quark-Gluon Plasma. In contrast, recent measurements of non-photonic electrons from heavy quark decays at high transverse momentum (pT) show a jet quenching level similar to that of the light hadrons. Heavy quark are produced mainly at early stage in heavy-ion collisions, thus they are proposed to probe the QCD medium and to be sensitive to bulk medium properties. Ultimately, their flow behavior may help establish whether light quarks thermalize. But due to the absence of the measurement of B-mesons and precise measurement of D-mesons, it is difficult to separate bottom and charm contributions experimentally in current non-photonic electron measurements for both spectra and elliptic flow v2. Therefore, topological reconstruction of D-mesons and identification of electrons from charm and bottom decays are crucial to understand the heavy flavor production and their in medium properties. The Heavy Flavor Tracker (HFT) is a micro-vertex detector utilizing active pixel sensors and silicon strip technology. The HFT will significantly extend the physics reach of the STAR experiment for precise measurement of charmed and bottom hadrons. We present a study on the open charm nuclear modification factor, elliptic flow v2 and λc measurement as well as the measurement of bottom mesons via a semi-leptonic decay. (author)

  14. B^0 Meson Reconstruction Through the J/ψ Decay Channel with the Heavy Flavor Tracker at STAR

    Science.gov (United States)

    Weiner, Joshua

    2008-10-01

    The Solenoidal Tracker at RHIC (STAR) is an ongoing experiment at the Relativistic Heavy Ion Collider (RHIC) located at Brookhaven National Laboratory. Its goals are to observe and study the characteristics of the quark-gluon plasma produced by nuclear collisions. The Heavy Flavor Tracker (HFT) is a new high-resolution vertex detector that has been proposed by STAR. The HFT will allow high-resolution tracking of charged particles, enabling the identification of particles containing charm and bottom quarks that decay hundreds of microns from the primary interaction vertex. The B^0-> J/ψ X and J/ψ->e^+e^- decay channels form a good candidate for B^0 meson detection due to the presence of the dielectron pair generated at a large distance from the primary vertex. Reconstruction of B^0 events mixed with Au-Au 200 GeV events was performed with HIJING, GEANT, and the STAR software library. We will show how the HFT can identify the B^0 events and what can be learned by identifying the B mesons.

  15. Single event and TREE latchup mitigation for a star tracker sensor: An innovative approach to system level latchup mitigation

    International Nuclear Information System (INIS)

    Electronic packages designed for spacecraft should be fault-tolerant and operate without ground control intervention through extremes in the space radiation environment. If designed for military use, the electronics must survive and function in a nuclear radiation environment. This paper presents an innovative ''blink'' approach rather than the typical ''operate through'' approach to achieve system level latchup mitigation on a prototype star tracker camera. Included are circuit designs, flash x-ray test data, and heavy ion data demonstrating latchup mitigation protecting micro-electronics from current latchup and burnout due to Single Event Latchup (SEL) and Transient Radiation Effects on Electronics (TREE)

  16. 船用星敏感器星图模拟方法%A Star Image Simulation Method for a Marine Star Tracker

    Institute of Scientific and Technical Information of China (English)

    李辉; 王安国; 张磊; 佟帅

    2013-01-01

    A high-precision real-time star image simulation method is proposed for the emulational test of a marine star tracker. The computation model for star image simulation is established, and the non-stellar elements simulation method is analyzed. The related algorithms are realized by Visual C++programming. Typical star image simulation examples are presented and compared with the star images generated by Starry Night. The results show that this proposed method can be used to achieve star image simulation for a marine star tracker under various operating conditions. The elements of simulation are complete and correct. The simulation accuracy is comparable to the accuracy of Starry Night at sub-pixel level. And the simulation time for each image is about 24.8 ms. This method meets well the basic requirements of high-precision real-time emulational test of a marine star tracker.%  针对船用星敏感器的仿真测试,提出一种高精度实时星图模拟方法.建立了星图模拟计算模型,并对非恒星要素的模拟方法进行分析.采用Visual C++编程实现相关算法.给出典型星图模拟实例,并与Starry Night软件产生的星图进行比对.结果表明,本文提出的方法能够对船用星敏感器各种运行场景下的星图进行模拟,模拟要素完整、正确,模拟精度与Starry Night接近至亚像素级别,每帧模拟星图生成时间约24.8 ms.能够满足船用星敏感器高精度实时仿真测试要求.

  17. Development of star tracker system for accurate estimation of spacecraft attitude

    OpenAIRE

    Tappe, Jack A.

    2009-01-01

    Approved for public release, distribution unlimited This thesis researches different star pattern recognition and attitude determination algorithms for a three-axis rotational spacecraft. A simulated star field will be suspended above the experimental Three-Axis Spacecraft simulator to proved a reference for the star-pattern recognition algorithms. A star field inertial reference frame database of stars will be developed with the simulator at zero attitude. The angle, planar triangle an...

  18. In-flight calibration and performance evaluation of the fixed head star trackers for the solar maximum mission

    Science.gov (United States)

    Thompson, R. H.; Gambardella, P. J.

    1980-01-01

    The Solar Maximum Mission (SMM) spacecraft provides an excellent opportunity for evaluating attitude determination accuracies achievable with tracking instruments such as fixed head star trackers (FHSTs). As a part of its payload, SMM carries a highly accurate fine pointing Sun sensor (FPSS). The EPSS provides an independent check of the pitch and yaw parameters computed from observations of stars in the FHST field of view. A method to determine the alignment of the FHSTs relative to the FPSS using spacecraft data is applied. Two methods that were used to determine distortions in the 8 degree by 8 degree field of view of the FHSTs using spacecraft data are also presented. The attitude determination accuracy performance of the in flight calibrated FHSTs is evaluated.

  19. FLAT: Folded Low-profile Autonomous star Tracker for cubesats/smallsats Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Perform trade studies over folded aperture optics to specify design parameters - diameter, effective aperture, sensitivity, field of view; Model, design, fabricate...

  20. Autonomous satellite constellation orbit determination using the star sensor and inter-satellite links data

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A method of autonomous orbit determination for a satellite constellation using a star sensor combined with inter satellite links(ISLs) is studied.Two types of simulated observation data,Three-Satellite Constellation ISLs and background stellar observations by a CCD star sensor,are first produced.Based on these data,an observation equation is built for the constellation joint autonomous orbit determination,in which the simulations are run.The accuracy of this method with different orbital determination models are analyzed and compared with regard to the effect of potential measurement errors.The results show that autonomous satellite constellation orbit determination using star sensor measurement and ISLs data is feasible.Finally,this paper arrives at several conclusions which contribute to extending this method to a more general satellite constellation.

  1. Contingency Operations during Failure of Inertial Attitude Acquisition Due to Star Tracker Blinding for Three-Axes-Stabilized Interplanetary Spacecraft

    Science.gov (United States)

    Keil, Joachim; Herfort, Ulrich

    2007-01-01

    The three interplanetary ESA missions Mars-Express, Rosetta and Venus-Express (launched 2003, 2004 and 2005 resp.) are three-axes stabilized spacecraft (s/c) that estimate their inertial attitude (i.e. the attitude of the s/c w.r.t. the inertial frame) using measurements from a redundant set of star trackers (STR). Each s/c is equipped with four reaction wheels, a reaction control system based on thrusters and a redundant set of ring laser gyroscopes (gyros). The STR h/w layout of the three s/c is identical whereas there is a difference in the star pattern recognition algorithm of Rosetta which uses five neighbouring stars around a central star instead of star triads. The Rosetta algorithm has been implemented to cope with the presence of false stars which are expected to be seen during operations around the comet. The attitude acquisition capability from lost in space is different also in terms of AOCMS: The survival mode of Rosetta which is entered upon STR failure is presented. The AOCMS of Mars- and Venus-Express manages temporary STR outages during sky occultation by the planet not even by using redundancy. Though, a blinding of both STR during cruise lasting for the order of days confronts the ground operators with the limits of the AOCMS design. The operations and analyses that have been planned and partially been performed to compensate for the outage of the STR are demonstrated for Mars-Express. The caution measures taken before Venus orbit insertion of Venus-Express are detailed.

  2. Optical System Error Analysis of High Accuracy Star Trackers%高精度星敏感器光学系统误差分析

    Institute of Scientific and Technical Information of China (English)

    孙婷; 邢飞; 尤政

    2013-01-01

    在对影响星敏感器精度的误差源做出权重分析和比较的基础上,提出一种基于蒙特卡罗模拟的星敏感器精度误差分析方法,避免冗长和繁琐的理论推导,直观且系统地分析了星敏感器误差传播关系,建立星敏感器误差传播模型,为星敏感器的优化设计、标定补偿提供依据和准则,通过仿真验证误差传播模型及误差分析方法的准确性,为高精度星敏感器的设计制造提供重要基础和保证.%A synthetic error analysis approach is proposed in detail based on error source weight analysis and comparison of the star tracker using Monte Carlo method. It can avoid long and cumbersome theoretical derivation, which can provide error propagation relation of the star tracker intuitively and systematacially. The error propagation model can provide foundation and rule for optimization design, calibration and compensation of the star tracker. Simulation consequences prove that the systematic analysis is adequate and precise, which can provides important guarantee for design and manufacture of high accuracy star trackers.

  3. The measurement of hadronic observables with the solenoidal tracker at RHIC (STAR)

    Energy Technology Data Exchange (ETDEWEB)

    Bellwied, R. [Wayne State Univ., Detroit, MI (United States)

    1995-07-15

    The authors describe the capabilities of the STAR detector at RHIC regarding the measurement of hadronic observables. Special emphasis will be given to the determination of event-by-event observables deduced from particle spectra for protons (p), kaons (K) and pions ({pi}). The authors show that based on the present status of the simulations STAR will be able to measure quantities such as , slope parameter, and particle ratios on an event-by-event basis. These parameters, in connection with charged particle multiplicities as a function of momentum and rapidity, may shed light on the occurance of a phase transition in ultrarelativistic heavy ion collisions.

  4. Heavy Flavor Tracker (HFT): A new inner tracking device at STAR

    Science.gov (United States)

    STAR Collaboration; Bouchet, J.; STAR Collaboration

    2009-11-01

    The HFT, a new inner tracking detector for STAR, aims to measure the charmed hadron nuclear modification factor as well as their elliptic flow to the low p region (˜0.5 GeV/c) by measuring the displaced vertices of charmed particles.

  5. Heavy Flavor Tracker (HFT): A new inner tracking device at STAR

    International Nuclear Information System (INIS)

    The HFT, a new inner tracking detector for STAR, aims to measure the charmed hadron nuclear modification factor as well as their elliptic flow to the low pT region (∼0.5 GeV/c) by measuring the displaced vertices of charmed particles.

  6. Heavy Flavor Tracker (HFT) : A new inner tracking device at STAR

    OpenAIRE

    Bouchet, Jonathan; Collaboration, for the STAR

    2009-01-01

    The HFT, a new inner tracking detector for STAR, aims to measure the charmed hadron nuclear modification factor as well as their elliptic flow to the low $p_\\mathrm{T}$ region ($\\sim$0.5 GeV/c) by measuring the displaced vertices of charmed particles.

  7. Heavy Flavor Tracker (HFT) : A new inner tracking device at STAR

    CERN Document Server

    2009-01-01

    The HFT, a new inner tracking detector for STAR, aims to measure the charmed meson nuclear modification factor as well as their elliptic flow in low $p_\\mathrm{T}$ region (0.5 - 2 GeV/c) by measuring the displaced vertices of charmed particles.

  8. In-flight scale/distortion calibration of the Hubble Space Telescope fixed-head star trackers

    Science.gov (United States)

    Mccutcheon, R.; Boia, John J.; Gakenheimer, Martin F.; Hallock, L.; Kimmer, E.; Murphy, S.; Welter, Gary L.

    1994-01-01

    This paper describes an in-flight scale and distortion calibration procedure that has been developed for the Ball Aerospace Systems Division Fixed-Head Star Trackers (FHST's) used on the Hubble Space Telescope (HST). The FHST is a magnetically focused and deflected imaging sensor that is designed to track stars as faint as m(sub v) = 5.7 over an 8 degree by 8 degree field of view. Raw FHST position measurements are accurate to approximately 200 arcseconds, but this can be improved to 10-15 arcseconds by processing the raw measurements through calibration polynomials that correct for flat field, temperature intensity, and magnetic field effects. The coefficients for these polynomials were initially determined using ground test data. On HST the use of three FHST's is an integral part of the preliminary attitude update procedures required before the acquisition of guide stars for science observations. To this end, FHST-based attitude determination having single-axis errors no worse than 22 arcseconds (1 sigma) is required. In early 1991 it became evident that one of the HST FHST's was experiencing a significant change in its optical scale. By mid-1993 the size of this error had grown to a point that, if not corrected, it would correspond to a maximum position error on the order of 100 arcseconds. Subsequent investigations demonstrated that substantial, uncompensated cubic distortion effects had also developed, the maximum contribution to position errors from the cubic terms being on the order of 30 arcseconds. To ensure accurate FHST-based attitude updates, procedures have been developed to redetermine the FHST scale and distortion calibration coefficients based on in-flight data gathered during normal HST operations. These scale and distortion calibrations have proven very effective operationally, and procedures are in place to monitor FHST calibration changes on a continuing basis.

  9. Experience from the in-flight calibration of the Extreme Ultraviolet Explorer (EUVE) and Upper Atmosphere Research Satellite (UARS) fixed head star trackers (FHSTs)

    Science.gov (United States)

    Lee, Michael

    1995-01-01

    Since the original post-launch calibration of the FHSTs (Fixed Head Star Trackers) on EUVE (Extreme Ultraviolet Explorer) and UARS (Upper Atmosphere Research Satellite), the Flight Dynamics task has continued to analyze the FHST performance. The algorithm used for inflight alignment of spacecraft sensors is described and the equations for the errors in the relative alignment for the simple 2 star tracker case are shown. Simulated data and real data are used to compute the covariance of the relative alignment errors. Several methods for correcting the alignment are compared and results analyzed. The specific problems seen on orbit with UARS and EUVE are then discussed. UARS has experienced anomalous tracker performance on an FHST resulting in continuous variation in apparent tracker alignment. On EUVE, the FHST residuals from the attitude determination algorithm showed a dependence on the direction of roll during survey mode. This dependence is traced back to time tagging errors and the original post launch alignment is found to be in error due to the impact of the time tagging errors on the alignment algorithm. The methods used by the FDF (Flight Dynamics Facility) to correct for these problems is described.

  10. Heavy Flavor Tracker (HFT): a New Silicon Detector for the STAR Experiment at RHIC

    International Nuclear Information System (INIS)

    The HFT is a silicon detector for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to achieve about an order of magnitude better track pointing (DCA) resolution. This will allow for a direct and full topological reconstruction of charmed meson decays (e.g. D0) and a better determination of the B-meson spectra. Key measurements include D0 elliptic flow (v2) determination, especially in the lower transverse momenta (pT) region, and identified heavy quark suppression studies at high pT via the nuclear modification factor (RCP and RAA). (author)

  11. Hubble Space Telescope Star Tracker ad Two-Gyro Control Law Design, Implementation, and On-Orbit Performance. Part 2

    Science.gov (United States)

    VanArsdall, John C.

    2005-01-01

    The Hubble Space Telescope (HST) normally requires three gyroscopes for three-axis rate control. The loss of the Space Shuttle Columbia on STS-107 resulted in the cancellation of a shuttle-based HST Servicing Mission 4. Therefore, HST must operate using the on-board hardware until an alternate means of servicing can be accomplished. The probability of gyro failure indicates that fewer than three gyros will be operable before any servicing mission can be performe& To mitigate this, and to extend the HST life expectancy, a rate estimation and control algorithm was developed that requires two gyros to measure rate about two axes, with the remaining axis rate estimated using one of three alternate sensors. Three-axis magnetometers (MSS) are used for coarse rate estimation during large maneuvers and during occultations of other sensors. Fixed-Head Star Trackers (FHSTs) are used for rate estimation during safe mode recovery and during transition to science operations. Fine rate estimation during science operations is performed using the Fine Guidance Sensors (FGSs). The FHST mode (T2G) relies on star vectors as measured by the FHSTs to estimate vehicle rate about the axis not measured by the gyros. Since the FHSTs were not designed to estimate body rate, this method involves a unique set of problems that had to be overcome in the final design, such as the effect of FHST break tracks and moving targets on rate estimation. The solutions to these problems, as well as a detailed description of the design and implementation of the rate estimation are presented Also included are the time domain and frequency domain analysis of the T2G control law. A high fidelity HST simulator (HSTSIM) was used to verify T2G performance prior to on-orbit use. Results of these simulations are also presented. Finally, analysis of actual T2G on-orbit test results is presented for design validation.

  12. Heavy Flavor Tracker (HFT): The new silicon vertex detector for the STAR experiment at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Margetis, Spiros [Kent State University, Ohio (United States)

    2011-01-15

    The HFT is the vertex-detector upgrade for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to increase by about an order of magnitude the track-pointing (DCA) resolution. This will allow direct and full topological reconstruction of charmed meson decays (e.g. D{sup 0}) and a better determination of the B-meson spectra. Key measurements include D{sup 0} elliptic flow (v{sub 2}) determination, especially in the lower transverse momenta (p{sub T}) region, and identified heavy quark suppression studies at high p{sub T} via the nuclear modification factor (R{sub CP} and R{sub AA}).

  13. Heavy Flavor Tracker (HFT): The new silicon vertex detector for the STAR experiment at RHIC

    International Nuclear Information System (INIS)

    The HFT is the vertex-detector upgrade for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to increase by about an order of magnitude the track-pointing (DCA) resolution. This will allow direct and full topological reconstruction of charmed meson decays (e.g. D0) and a better determination of the B-meson spectra. Key measurements include D0 elliptic flow (v2) determination, especially in the lower transverse momenta (pT) region, and identified heavy quark suppression studies at high pT via the nuclear modification factor (RCP and RAA).

  14. Heavy Flavor Tracker (HFT): The new silicon vertex detector for the STAR experiment at RHIC

    Science.gov (United States)

    Margetis, Spiros; STAR Collaboration

    2011-01-01

    The HFT is the vertex-detector upgrade for the STAR experiment at RHIC. It is replacing the decommissioned silicon drift detector (SVT) with active pixel technology close to the beam pipe in order to increase by about an order of magnitude the track-pointing (DCA) resolution. This will allow direct and full topological reconstruction of charmed meson decays (e.g. D 0) and a better determination of the B-meson spectra. Key measurements include D 0 elliptic flow (v 2) determination, especially in the lower transverse momenta ( pT) region, and identified heavy quark suppression studies at high pT via the nuclear modification factor ( R and R).

  15. A computer-aided telescope pointing system utilizing a video star tracker

    Science.gov (United States)

    Lorell, K. R.; Murphy, J. P.; Swift, C. D.

    1976-01-01

    The Video Inertial Pointing (VIP) System is being developed to satisfy the acquisition and pointing requirements of astronomical telescopes. VIP employs a single video sensor to generate three-axis pointing error signals and to provide inputs for a cathode ray tube (CRT) display of the star field. The pointing error signals update the telescope's gyro stabilization system. The CRT display facilitates target acquisition and positioning of the telescope by a remote operator. The present paper describes the analysis, simulation, and hardware development of a prototype, advanced VIP system. An early model of the system utilizing a silicon-intensified target vidicon camera has flown on a balloon-borne telescope and is briefly described. The advanced system, which can employ either a vidicon camera or a charge-coupled device video sensor, has been tested using an analog/digital hybrid simulation. The advanced VIP hardware is described, and the simulation results presented.

  16. The secure, transportable, autonomous reactor (STAR): a small proliferation-resistant reactor system for developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N W; Hassberger, J A; Smith, C F

    1999-05-27

    The Secure, Transportable, Autonomous Reactor (STAR), is an integrated concept for a small, proliferation-resistant nuclear power system capable of meeting the growing power demands of many regions of the developing world. The STAR approach builds on earlier work investigating the features required for implementation of such a system. The STAR approach includes establishing overall system requirements, conducting research into issues common to four reactor concepts (gas, liquid metal, light water and molten salt), and defining and performing the down-selection to a preferred concept that will serve as the basis for continued development leading to an eventual prototype. The paper indicates that a number of unique and distinguishing innovations are needed to both meet the energy demands of most of the world's developing regions and address growing nuclear proliferation concerns. These technical innovations form much of the basis underlying the STAR concept and include: eliminating on-site refueling and fuel access; incorporating a systems approach to nuclear energy supply and infrastructure design, with all aspects of equipment life, fuel and waste cycles included; small unit size enabling transportability; replaceable standardized modular design; resilient and robust design concepts leading to large safety margins, high reliability and reduced maintenance; simplicity in operation with reliance on autonomous control and remote monitoring; and waste minimization and waste form optimization.

  17. 捷联惯性/大视场星光组合导航方法研究%The Research on Integrated Navigation Method of SINS/Star with Large View Field Star Tracker

    Institute of Scientific and Technical Information of China (English)

    李双喜; 张宗梅; 张俊

    2011-01-01

    Recently, the integrated navigation using star tracker in missiles and rockets becomes a hotspot in both domestic and oversea. The integrated navigation method of SINS/Star with large view field star tracker is studied and the Kalman filter equation is established in this paper. Using the SINS error transfer matrix method, the navigation error of ballistic missile in ascend phase is also estimated. The simulation resubs show that the integrated navigation method of SINS/Star with large view field star tracker can revise attitude angle error and gyroscope constant drift while the velocity and position error in ascend phase can also be estimated.%近年来,使用星敏感器的导弹、火箭惯性组合导航成为国内外研究的热点.本文对捷联惯性/大视场星光组合导航方法进行了研究,建立了卡尔曼滤波方程,并利用SINS误差转移矩阵方法估计主动段导航误差.数学仿真表明:捷联惯性/大视场星光组合导航方法不仅可以修正姿态角偏差和陀螺常值漂移,还可以对主动段的速度、位置误差有很好的估计效果.

  18. STARS: A software application for the EBEX autonomous daytime star cameras

    CERN Document Server

    Chapman, Daniel; Hanany, Shaul; Hillbrand, Seth; Limon, Michele; Miller, Amber; Reichborn-Kjennerud, Britt; Tucker, Greg; Vinokurov, Yury

    2014-01-01

    The E and B Experiment (EBEX) is a balloon-borne telescope designed to probe polarization signals in the CMB resulting from primordial gravitational waves, gravitational lensing, and Galactic dust emission. EBEX completed an 11 day flight over Antarctica in January 2013 and data analysis is underway. EBEX employs two star cameras to achieve its real-time and post-flight pointing requirements. We wrote a software application called STARS to operate, command, and collect data from each of the star cameras, and to interface them with the main flight computer. We paid special attention to make the software robust against potential in-flight failures. We report on the implementation, testing, and successful in flight performance of STARS.

  19. Thermo-optic Effects on Accuracy Performance of Star Tracker%热-光效应对星敏感器测量准确度的影响

    Institute of Scientific and Technical Information of China (English)

    刘海波; 黄水花; 谭吉春; 贾辉; 杨建坤; 杨俊才

    2009-01-01

    Thermo-optic effects on position accuracy of star tracker was analysised using opto-mechanical coupling method.The displacements of star centroids and sub-pixel interpolation errors,caused by three kinds of temperature distribution respectively,were calculated quantitatively in a typical optical system of star tracker.The measurement error of star tracker was about 0.07″,when uniform temperature changed 20℃.The measurement errors were about 0.17″and 0.31″,respectively,when temperature difference were 10℃ and 20℃ in axis.And it was as much as 1.46″,when temperature distribution difference between top of the optical system and the bottom was only 2℃.The results show that temperature distribution difference between the top and the bottom has serious effects on measurement accuracy of star tracker,and uniform temperature distribution has a little.%运用"热-结构-光"耦合分析方法,计算典型星敏感器光学系统(6透镜光具组,f=56 mm,相对孔径1/1.3)恒星像斑理想质心位移和亚像元内插质心偏移量,研究温度分布对星敏感器测量准确度的影响.以20℃为光学系统标定温度,计算光学系统均匀温度分布、轴向温差分布和上下侧温差分布三种条件下,星敏感器测量误差.均匀分布温度变化20℃时,星敏感器测量误差约0.07″;轴向温差10℃和20℃时,测量误差分别约为0.17″和0.31″;上下侧温差仅2℃时,测量误差就高达1.46″.计算结果表明,上下侧温差分布对星敏感器准确度影响最大,均匀温度分布影响最小.

  20. Optimized Design of Optical Lens of Star Tracker%星跟踪器光学系统的优化设计

    Institute of Scientific and Technical Information of China (English)

    王立秋; 田明; 崔士宝

    2015-01-01

    在星光制导的空间飞行器中,为准确确定空间方位信息,提高导航系统的精度,对星跟踪器光学镜头设计提出很高的要求。针对精度要求,设计了一种新型星跟踪器的光学镜头,系统地阐述了星跟踪器的工作原理,通过光学设计及相差分析,使光学系统的畸变小于0.2%、轴向球差小于0.1,该设计满足用户对高精度天文导航系统的需求。%In the star light guidance of space vehicles, the optical lens design requirements for star tracker are critical to determine accurately the spatial location information and to improve the accuracy of navigation system. A new type of star tracker optical lens system is designed according to the requirements and the operation principle is presented. With the optical design and difference analysis, the optical system distortion is less than 0.2%, the axial spherical aberration is less than 0.1, which can meet the demand for high-precision astronomical navigation system.

  1. Assessment of reactivity coefficient uncertainty effects upon STAR-LM autonomous operation and passive safety

    International Nuclear Information System (INIS)

    The STAR-LM 300 to 400 MWt class modular, factory fabricated, fully transportable, proliferation resistant, autonomous, natural circulation reactor achieves autonomous load following and passive power shutdown as a consequence of the fast neutron spectrum core utilizing lead-bismuth eutectic coolant, transuranic nitride fuel, and ferritic-martensitic stainless steel cladding. A first principles model has been developed to calculate the final steady state peak cladding temperature, mean fuel, coolant outlet, and coolant inlet temperatures following an autonomous change in core power to match a change in heat removal. The model is based upon zero net reactivity change between the initial and final states; final temperatures depend explicitly upon reactivity feedback coefficients, final core power/heat removal rate, and the initial temperatures. The model is applied to determine the effects of uncertainties inherent in the calculation of the reactivity feedback coefficients. Uncertainty effects are quantified in terms of the cumulative probability and probability density distributions for the peak cladding temperature. The probability that the peak cladding temperature density exceeds a temperature criterion of 650degC based upon interaction of lead-bismuth melt and the cladding is shown to be zero for the 300 MWt design and small or zero for the 400 MWt design. (author)

  2. 适用于小视场星敏感器的导航星表构建方法%Guide star selection method for star tracker with thin field of view

    Institute of Scientific and Technical Information of China (English)

    崔祥祥; 王宏力; 陆敬辉; 乔兴; 邓长智; 张勇; 赵爱罡

    2015-01-01

    Guide star selection is a crucial part of star tracker design. For thin field-of-view star tracker, guide star catalog "holes" are common as stars are not evenly distributed. To optimize the guide star selection for star tracker with thin field of view, the selection method based on spherical spiral points was modified. Building a new guide star catalog by increasing the number and changing the positions of spherical spiral points, which was usually adopted, was abandoned. Some new stars which can effectively decrease guide star catalog "holes" into the guide star catalog were proposed. The weights to measure stars’ ability of decreasing guide star catalog "holes" were constructed and the adding star process was carried out on the order of the weights descending. And the new star added into guide star catalog was required far away from the guide stars to keep the guide stars even. Simulations expressed that the modified method got less and evener guide stars than the original method with similar guide star catalog"holes", which shows the superiority of the modified method.%导航星表构建是星敏感器设计阶段的重要工作。对于小视场,受限于恒星分布规律,易出现导航星表“空洞”问题。为解决小视场条件下均匀完备导航星表构建问题,对基于球面螺旋基准点的导航星表构建方法进行了改进:摒弃了原方法通过改变球面螺旋基准点数量和位置重新构建导航星表的思路,转而通过增选部分恒星来达到减少星表“空洞”的目的。设立了描述恒星消除星表“空洞”能力的权值,并以该权值递减顺序开展恒星增选;同时,设计了增选恒星距离阈值条件以保持增选后导航星表的均匀性。仿真表明,在4º圆形视场条件下,相对于原方法,文中方法得到的导航星表,总星数减少708颗,均匀性指标提高约44%,而星表“空洞”变化较小,显示了较好的性能。

  3. Analysis of influence of earth albedo on star tracker%地球反照对星敏感器的影响分析

    Institute of Scientific and Technical Information of China (English)

    张春明; 解永春; 王立; 赵春晖; 钟红军

    2012-01-01

    A geometry optical model for analyzing the influence of earth albedo on star tracker is presented. Based on the principle of photometry and Point Source Transmittance(PST) ,this model has a certain generality and practicability by means of dividing earth surfaces into 2D cells with longitude and attitude and providing application interface of available TOMS reflectance data. It can be used to analyze the magnitude of irradiance of entrance and exit of a sunshade and corresponding imaging surface at different off-axis angles,where earth albedo pours on within some conditions, including altitude of orbit,installing position of star tracker,incident angle of sun,etc. Based on this model,we can make proposal of installing orientation of star tracker on satellites and estimate anti-earth albedo performance of sunshade of star tracker. Simulation indicates that for MEO and LEO, the irradiance of earth albedo reaching the entrance of sunshade of star tracker changes little, the magnitude of irradiance of earth albedo received by the exit of sunshade is mainly related to its PST and installation elevation; When this angle is equal to 32. 5°,the irradiance of the exit of sunshade declines to 10 -7 W/m2 ,thus satisfying sunshade's requirement of suppressing stray light.%利用光度学的概念和点源辐射传输率(PST),提出了一种分析地球反照对星敏感器的影响的几何光学模型.该模型对地球表面按照经纬度划分了网格,为已知的TOMS反射数据的应用提供了接口,具有一定的通用性和实用性,可简要分析卫星上的星敏感器在一定输入条件下,包括轨道高度、星敏感器的安装方位、太阳入射角度等,地球反照到达遮光罩入口、出口的照度,以及不同离轴角下像面接收的地球反照的照度值.借助此模型,可以为星敏感器在卫星上的安装方位提出建议,并估算出星敏感器遮光罩的抗地球反照干扰性能.仿真分析表明,对于中低轨道而言,

  4. 一种新的方法用于星敏感器近红外星图星点提取%A new method used for star distillation of near-infrared star image of star tracker

    Institute of Scientific and Technical Information of China (English)

    廖育富; 钟建勇

    2014-01-01

    分析了近红外星图小波分解系数的特点。依据小波分析的边缘检测特性、解相关性和多分辨率特性结合星点的灰度分布特征设计了不同尺度下的检测模板。在恒虚警概率条件下,提出利用局部阈值克服红外星图本身的背景不均匀性。通过在星图第二次分解的近似系数上检测星点最大灰度值的位置,削弱了单点噪声和条纹噪声的影响。实验结果显示,算法能有效得出视场中的星点最大灰度值坐标,误差在1个像素位置左右,满足后续星点提取的需要。%The distillation of near-infrared star image of star tracker was analyzed in this paper. A new method for this problem was presented. Firstly, characters of near-infrared star image in wavelet domain were analyzed and mask used to detect stars in multi scales were designed according to the distribution of the gray of stars. Then, local threshold was applied to overcome the imbalance of the background under the constant false alarm rate. Lastly, positions of the heaviest gray values of stars in the secondly decomposed approximation coefficients were accessed, eliminating the effect of the single point noise and stripe noise. Experimental results indicate that the method could efficiently obtain the position of the heaviest gray value of detected stars with error around one pixel, which satisfies the requirement of estimation of centroid.

  5. Modeling and accuracy analysis for multiple heads star tracker%多视场星敏感器数学模型与精度分析

    Institute of Scientific and Technical Information of China (English)

    李健; 张广军; 魏新国

    2015-01-01

    多视场星敏感器与传统单视场星敏感器相比不仅具有更高的可靠性和自主性,也具有更高的精度和动态性能,是未来星敏感器发展的重要趋势之一。为获得最佳性能,需要对多视场星敏感器的视场大小和布局进行优化。为此,首先建立了多视场星敏感器的数学模型,重点介绍了星点成像和姿态计算。然后推导了多视场星敏感器测量精度的数学表示,分析了影响精度的因素。通过仿真分析了多视场星敏感器视场大小和布局对各因素和精度的影响。仿真结果表明,视场大小对星敏感器精度的影响取决于星敏感器的运动情况,当角速度较小时,视场越小,精度越高;当角速度较大时,视场越大,精度越高。而各视轴相互正交的视场布局下,多视场星敏感器的测量精度最高。%As an important trend in the future, multiple heads star tracker is not only of higher reliability and autonomy, but also of higher precision and dynamic performance than classical star tracker. In order to achieve the best performance, system parameters optimization for multiple heads star tracker is needed. A mathematical model of multiple heads star tracker was developed firstly, particularly on the star imaging and attitude determination. Then an analytic expression of accuracy was deduced, and the error sources affecting the attitude accuracy were analyzed. Finally, the effects of the field of view and the relative alignment on the accuracy were discussed systematically based on the simulation results. The results show that the relation between field of view and accuracy depends on the angular rate. The accuracy is improved with smaller field of view at lower angular rate, while with larger field of view at higher angular rate. And multiple heads star sensor reaches the highest precision when the boresights are orthogonal.

  6. GLAST Tracker

    CERN Document Server

    Tajima, H

    2006-01-01

    The Large Area Telescope (LAT) on board the Gamma-ray Large-Area Space Telescope (GLAST) is a pair-conversion gamma-ray detector designed to explore the gamma-ray universe in the 20 MeV-300 GeV energy band. The Tracker subsystem of the LAT will perform tracking of electron and positrons to determine the origin of the gamma-ray. The design and performance of the GLAST LAT Tracker are described in this paper.

  7. INNER TRACKER

    CERN Multimedia

    Karl Gill

    A series of important milestones have been passed during the last 3 months. With the delivery of refurbished cooling systems, pixels and strip systems have been brought back into operation after long shutdowns. Pixels has been operating since reinsertion of FPIX in April, and has been running at 4°C since May 16 when the bulkhead thermal screen was commissioned. More recently, on June 10 the Strip Tracker was powered up in its entirety, with cooling fluid circulating at 4°C, allowing commissioning of the Strip Tracker to proceed at full speed. The full Tracker is well on course to be ready for CRAFT, with Strip Tracker readout operation in ‘peak’ mode remaining also on track to be ready for beam operations in the Autumn in ‘deconvolution’ readout mode. The main Tracker activity during the shutdown was the cooling plant refurbishment for Strips and Pixels systems. The objectives were to reduce the serious leaks observed in 2008 and improve the longevity...

  8. INNER TRACKER

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The Objective for 2007 is to deliver to CMS a completed, installed, commissioned and calibrated Tracking System (Silicon Strip and Pixels) aligned to < 100µ in April 2008 ready for the first physics collisions at LHC. On 21 March 2007, the integration of the CMS Silicon Strip Tracker was completed with the successful integration of TEC- into the Tracker Support Tube (TST). Since then ~25% of the complete Tracker Systems has been commission at the TIF at both room temperature and operating temperature (-100 C), and the Tracker Community has gained very valuable experience in operating, calibrating and aligning the Tracker at the TIF before it is prepared for transportation to P5 in July 2007. The CMS Pixel System continues to make good progress. Module and Plaquette production is very well advanced. The first 25% of the Forward Pixel detector (Fpix) was delivered to CERN in April and the second 25% will shipped to CERN on 19 ...

  9. INNER TRACKER

    CERN Multimedia

    K. Gill.

    The clear highlight of recent months was switching on the Tracker to capture the first LHC collisions with 450GeV beams. This was during the first trial run of the LHC on 23rd November. On that day, the Tracker Outer Barrel (TOB) was powered and the detector performance was excellent, in accord with our expectations. Since then, the full Tracker, strips and pixels, has been powered up during “quiet” beam periods when there was judged to be little risk of damage due to sudden beam losses. All Tracker systems performed very well, considering the beam and trigger conditions in place, and we now eagerly anticipate the first collisions with stable beams. Besides this very intense and exciting recent period there has been a lot of other activity in the last 6 months. The full Tracker participated in CRAFT09 and operations of all systems went very smoothly for both pixels and strips, validating all the meticulous work that had taking place during the long shutdown, the subsequent re-commissionin...

  10. INNER TRACKER

    CERN Multimedia

    K. Gill

    During the winter shutdown several parts of the Tracker system are undergoing maintenance, revision or upgrade. The main items are the revision of the strips and pixels cooling plants, removal and maintenance of FPIX, sealing of Tracker patch-panels and the bulkhead, integration of strips and pixels DCS, and further development of the DAQ, Online and commissioning software and firmware. The revision of the cooling system involves the complete replacement of the tanks, distribution lines, valves and manifolds on the SS1 and SS2 strip tracker (182 circuits) and pixels (36 circuits) cooling plants. The objectives are to eliminate the large leaks experienced during 2008 operations and to assure the long-term reliability of the cooling systems. Additional instrumentation is being added to provide more detailed monitoring of the performance of the cooling system. This work is proceeding smoothly under close supervision. Procurements are almost completed and the quality of delivered parts and the subsequent assembl...

  11. Results from a Prototype MAPS Sensor Telescope and Readout Systemwith Zero Suppression for the Heavy Flavor Tracker at STAR

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, Leo C.; Matis, Howard S.; Ritter, Hans G.; Rose, AndrewA.; Stezelberger, Thorsten; Sun, Xiangming; Szelezniak, Michal A.; Thomas, James H.; Vu, Chinh Q.; Wieman, Howard H.

    2008-02-11

    We describe a three Mimostar-2 Monolithic Active PixelSensor (MAPS) sensor telescope prototype with an accompanying readoutsystem incorporating on-the-fly data sparsification. The system has beencharacterized and we report on the measured performance of the sensortelescope and readout system in beam tests conducted both at the AdvancedLight Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) and inthe STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Thiseffort is part of the development and prototyping work that will lead toa vertex detector for the STAR experiment.

  12. Results from a Prototype MAPS Sensor Telescope and Readout System with Zero Suppression for the Heavy Flavor Tracker at STAR

    OpenAIRE

    Greiner, Leo C.; Matis, Howard S.; Ritter, Hans G.; Rose, Andrew A.; Stezelberger, Thorsten; Sun, Xiangming; Szelezniak, Michal A.; Thomas, James H.; Vu, Chinh Q.; Wieman, Howard H.

    2008-01-01

    We describe a three Mimostar-2 Monolithic Active Pixel Sensor (MAPS) sensor telescope prototype with an accompanying readout system incorporating on-the-fly data sparsification. The system has been characterized and we report on the measured performance of the sensor telescope and readout system in beam tests conducted both at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) and in the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). This effo...

  13. 一种基于天体运动学的星敏感器精度测量方法%Accuracy measurement of star trackers based on astronomy

    Institute of Scientific and Technical Information of China (English)

    孙婷; 邢飞; 尤政

    2012-01-01

    Star trackers the highest accuracy attitude measurement devices used in spacecraft. The star tracker's accuracy is especially important. A method was given to measure the accuracy of a star tracker based on astronomical principles using the earth's rotation. The star tracker's position is fixed to the earth while taking photographs of stars. The celestial coordinates in the star catalogue stored in the star tracker are transformed from the J2000.0 coordinate system to an earth fixed coordinate system taking into account axial precession, nutation, proper motion and the earth's rotation. Pointing and roll accuracy curves are acquired after the star extraction, star map recognition and attitude solution. This method conveniently, efficiently and accurately measures the star tracker's accuracy while avoiding traditional complex operations. Tests using a precise star simulator and a three-axis table verify the system's accuracy.%星敏感器是目前应用在航天飞行器中精度最高的姿态测量器件,因此其精度的标定显得尤为重要。该文提出了一种基于天体运动学规律的星敏感器精度测量方法,利用地球自转的精密性,将星敏感器与地球固连,对天顶邻域拍摄星图。同时将存储在星敏感器内的导航星表由J2000.0坐标系在考虑恒星自行、岁差、章动及地球自转影响后变换到地固坐标系,经过星点提取、星图识别和姿态解算,得到星敏感器俯仰、偏航和滚转三轴在地固坐标系中的变化,根据统计规律得出星敏感器的指向精度和滚转精度。该测量方法方便易实施,可以避免传统测试方法操作复杂、需要精密转台和星模拟器的困扰,测量精度满足星敏感器要求,具有准确性和真实性。

  14. INNER TRACKER

    CERN Multimedia

    Peter Sharp

    In March the Silicon Strip Detector had been successfully connected to the PP1 patch panels on the CMS Cryostat, and every thing had been prepared to check out the Tracker and commission it with CMS with the ambition of joining the CMS Global Cosmic Run in April.  There followed serious problems with the cooling plant which through tremendous effort have been overcome and recently allowed commissioning of the tracker to proceed. In November 2007 there had been a failure of the heat exchanger in one of the seven cooling plants in the UXC cavern. After an analysis of the failure it was decided to replace this heat exchanger with a well-proven commercial heat exchanger and to re-commission the system. Re-commissioning the system proved to be more difficult than anticipated as on May 8 there was a second failure of a heat exchanger, in the main chiller plant in the USC service cavern. The analysis of the failure showed it was very similar to the previous failure. It was decided to replace all the heat ...

  15. The electromagnetic calorimeter for the solenoidal tracker at RHIC

    International Nuclear Information System (INIS)

    This report discusses the following on the electromagnetic calorimeter for the solenoidal tracker at RHIC: conceptual design; the physics of electromagnetic calorimetry in STAR; trigger capability; integration into STAR; and cost, schedule, manpower, and funding

  16. Brightness Independent 4-Star Matching Algorithm for Lost-in-Space 3-Axis Attitude Acquisition

    Institute of Scientific and Technical Information of China (English)

    DONG Ying; XING Fei; YOU Zheng

    2006-01-01

    A star identification algorithm was developed for a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) autonomous star tracker to acquire 3-axis attitude information for a lost-in-space spacecraft. The algorithm took advantage of an efficient on-board database and an original "4-star matching" pattern recognition strategy to achieve fast and reliable star identification. The on-board database was composed of a brightness independent guide star catalog (mission catalog) and a K-vector star pair catalog. The star pattern recognition method involved direct location of star pair candidates and a simple array matching procedure. Tests of the algorithm with a CMOS active pixel sensor (APS) star tracker result in a 99.9% success rate for star identification for lost-in-space 3-axis attitude acquisition when the angular measurement accuracy of the star tracker is at least 0.01°. The brightness independent algorithm requires relatively higher measurement accuracy of the star apparent positions that can be easily achieved by CCD or CMOS sensors along with subpixel centroiding techniques.

  17. Interacting Multiview Tracker.

    Science.gov (United States)

    Yoon, Ju Hong; Yang, Ming-Hsuan; Yoon, Kuk-Jin

    2016-05-01

    A robust algorithm is proposed for tracking a target object in dynamic conditions including motion blurs, illumination changes, pose variations, and occlusions. To cope with these challenging factors, multiple trackers based on different feature representations are integrated within a probabilistic framework. Each view of the proposed multiview (multi-channel) feature learning algorithm is concerned with one particular feature representation of a target object from which a tracker is developed with different levels of reliability. With the multiple trackers, the proposed algorithm exploits tracker interaction and selection for robust tracking performance. In the tracker interaction, a transition probability matrix is used to estimate dependencies between trackers. Multiple trackers communicate with each other by sharing information of sample distributions. The tracker selection process determines the most reliable tracker with the highest probability. To account for object appearance changes, the transition probability matrix and tracker probability are updated in a recursive Bayesian framework by reflecting the tracker reliability measured by a robust tracker likelihood function that learns to account for both transient and stable appearance changes. Experimental results on benchmark datasets demonstrate that the proposed interacting multiview algorithm performs robustly and favorably against state-of-the-art methods in terms of several quantitative metrics. PMID:26336117

  18. STAR: The Secure Transportable Autonomous Reactor System - Encapsulated Fission Heat Source

    International Nuclear Information System (INIS)

    OAK-B135 The Encapsulated Nuclear Heat Source (ENHS) is a novel 125 MWth fast spectrum reactor concept that was selected by the 1999 DOE NERI program as a candidate ''Generation-IV'' reactor. It uses Pb-Bi or other liquid-metal coolant and is intended to be factory manufactured in large numbers to be economically competitive. It is anticipated to be most useful to developing countries. The US team studying the feasibility of the ENHS reactor concept consisted of the University of California, Berkeley, Argonne National Laboratory (ANL), Lawrence Livermore National Laboratory (LLNL) and Westinghouse. Collaborating with the US team were three Korean organizations: Korean Atomic Energy Research Institute (KAERI), Korean Advanced Institute for Science and Technology (KAIST) and the University of Seoul, as well as the Central Research Institute of the Electrical Power Industry (CRIEPI) of Japan. Unique features of the ENHS include at least 20 years of operation without refueling; no fuel handling in the host country; no pumps and valves; excess reactivity does not exceed 1$; fully passive removal of the decay heat; very small probability of core damaging accidents; autonomous operation and capability of load-following over a wide range; very long plant life. In addition it offers a close match between demand and supply, large tolerance to human errors, is likely to get public acceptance via demonstration of superb safety, lack of need for offsite response, and very good proliferation resistance. The ENHS reactor is designed to meet the requirements of Generation IV reactors including sustainable energy supply, low waste, high level of proliferation resistance, high level of safety and reliability, acceptable risk to capital and, hopefully, also competitive busbar cost of electricity

  19. STAR: The Secure Transportable Autonomous Reactor System - Encapsulated Fission Heat Source

    Energy Technology Data Exchange (ETDEWEB)

    Ehud Greenspan

    2003-10-31

    OAK-B135 The Encapsulated Nuclear Heat Source (ENHS) is a novel 125 MWth fast spectrum reactor concept that was selected by the 1999 DOE NERI program as a candidate ''Generation-IV'' reactor. It uses Pb-Bi or other liquid-metal coolant and is intended to be factory manufactured in large numbers to be economically competitive. It is anticipated to be most useful to developing countries. The US team studying the feasibility of the ENHS reactor concept consisted of the University of California, Berkeley, Argonne National Laboratory (ANL), Lawrence Livermore National Laboratory (LLNL) and Westinghouse. Collaborating with the US team were three Korean organizations: Korean Atomic Energy Research Institute (KAERI), Korean Advanced Institute for Science and Technology (KAIST) and the University of Seoul, as well as the Central Research Institute of the Electrical Power Industry (CRIEPI) of Japan. Unique features of the ENHS include at least 20 years of operation without refueling; no fuel handling in the host country; no pumps and valves; excess reactivity does not exceed 1$; fully passive removal of the decay heat; very small probability of core damaging accidents; autonomous operation and capability of load-following over a wide range; very long plant life. In addition it offers a close match between demand and supply, large tolerance to human errors, is likely to get public acceptance via demonstration of superb safety, lack of need for offsite response, and very good proliferation resistance. The ENHS reactor is designed to meet the requirements of Generation IV reactors including sustainable energy supply, low waste, high level of proliferation resistance, high level of safety and reliability, acceptable risk to capital and, hopefully, also competitive busbar cost of electricity.

  20. D^0 measurements in Au+Au Collisions at \\sqrt{s_{NN}} = 200 GeV using the STAR Silicon Inner Tracker

    CERN Document Server

    2009-01-01

    We present preliminary results from D^0 meson measurements through the hadronic decay channel in minimum bias Au+Au collisions at \\sqrt{s_{NN}} = 200 GeV at STAR. The measurements are performed using a secondary vertexing technique that exploits the resolution given by the Silicon detectors available in STAR.

  1. ATLAS Transitional Radiation Tracker

    CERN Multimedia

    ATLAS Outreach

    2006-01-01

    This colorful 3D animation is an excerpt from the film "ATLAS-Episode II, The Particles Strike Back." Shot with a bug's eye view of the inside of the detector. The viewer is taken on a tour of the inner workings of the transitional radiation tracker within the ATLAS detector. Subjects covered include what the tracker is used to measure, its structure, what happens when particles pass through the tracker, how it distinguishes between different types of particles within it.

  2. 星敏感器参数分析与自主校正%Star tracker parametric analysis for autonomous calibration

    Institute of Scientific and Technical Information of China (English)

    邢飞; 董瑛; 武延鹏; 尤政

    2005-01-01

    星敏感器焦距和主光轴偏心等参数对整个系统产生较大的影响.该文定量地分析了星敏感器星点坐标处理精度、主光轴位置和焦距误差对星图识别的影响,利用观星实验设计了一种自主进行参数校正的方法并给出了设计原则.对APS CMOS星敏感器进行了参数校正,并利用校正后的参数进行观星实验,星图识别成功率达到100%. 理论分析和实验结果表明,该方法可用于星敏感器的系统设计和参数的自主校正.

  3. Development of a digital mobile solar tracker

    Directory of Open Access Journals (Sweden)

    S. Baidar

    2015-11-01

    Full Text Available We have constructed and deployed a fast digital solar tracker aboard a moving ground-based platform. The tracker consists of two rotating mirrors, a lens, an imaging camera, and a motion compensation system that provides the Euler angles of the mobile platform in real time. The tracker can be simultaneously coupled to UV-Vis and FTIR spectrometers making it a versatile tool to measure the absorption of trace gases using solar incoming radiation. The integrated system allows the tracker to operate autonomously while the mobile laboratory is in motion. Mobile direct sun Differential Optical Absorption Spectroscopy (mobile DS-DOAS observations using this tracker were conducted during summer 2014 as part of the Front Range Photochemistry and Pollution Experiment (FRAPPE in Colorado, USA. We demonstrate an angular precision of 0.052° (about 1/10 of the solar disk diameter during research drives, and verify this tracking precision from measurements of the center to limb darkening (CLD, the changing appearance of Fraunhofer lines in the mobile DS-DOAS spectra. The high photon flux from direct sun observation enables measurements of nitrogen dioxide (NO2 slant columns with high temporal resolution, and reveals spatial detail in the variations of NO2 vertical column densities (VCDs. The NO2 VCD from DS-DOAS is compared with a co-located MAX-DOAS instrument. Overall good agreement is observed amid a highly heterogeneous air mass.

  4. Development of a digital mobile solar tracker

    Science.gov (United States)

    Baidar, Sunil; Kille, Natalie; Ortega, Ivan; Sinreich, Roman; Thomson, David; Hannigan, James; Volkamer, Rainer

    2016-03-01

    We have constructed and deployed a fast digital solar tracker aboard a moving ground-based platform. The tracker consists of two rotating mirrors, a lens, an imaging camera, and a motion compensation system that provides the Euler angles of the mobile platform in real time. The tracker can be simultaneously coupled to UV-Vis and Fourier transform infrared spectrometers, making it a versatile tool to measure the absorption of trace gases using solar incoming radiation. The integrated system allows the tracker to operate autonomously while the mobile laboratory is in motion. Mobile direct sun differential optical absorption spectroscopy (mobile DS-DOAS) observations using this tracker were conducted during summer 2014 as part of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) in Colorado, USA. We demonstrate an angular precision of 0.052° (about 1/10 of the solar disk diameter) during research drives and verify this tracking precision from measurements of the center to limb darkening (CLD, the changing appearance of Fraunhofer lines) in the mobile DS-DOAS spectra. The high photon flux from direct sun observation enables measurements of nitrogen dioxide (NO2) slant columns with high temporal resolution and reveals spatial detail in the variations of NO2 vertical column densities (VCDs). The NO2 VCD from DS-DOAS is compared with a co-located MAX-DOAS instrument. Overall good agreement is observed amid a highly heterogeneous air mass.

  5. 捷联惯导基于星体跟踪器的高精度初始对准算法%Precise SINS initial alignment algorithm based on star tracker

    Institute of Scientific and Technical Information of China (English)

    张金亮; 秦永元; 吴枫

    2013-01-01

      捷联惯导与小视场星体跟踪器构成惯性/天文组合导航系统,导航精度受导航初始误差和器件误差的综合影响。基于此,提出一种捷联惯导与小视场星体跟踪器相组合的初始对准算法,对导航初始姿态误差和惯性器件误差进行估计修正。捷联惯导初始对准过程完成之后,在地面准静基座条件下做速度和位置阻尼条件下的惯导更新解算,利用捷联惯导系统的速度误差量测及小视场星体跟踪器的导航误差角测量量,设计组合粗对准算法和组合精对准算法,用于对捷联惯导系统的初始对准误差和惯性器件误差做进一步有效估计。仿真结果表明:对中等精度导航级捷联惯导系统,组合对准后水平姿态精度可提高到2',方位精度可提高到5'。%Inertial/celestial integrated navigation system, which is composed of SINS and star tracker, may be influenced by initial errors and inertial sensor errors. To solve this problem, an integrated initial alignment algorithm was proposed to estimate and correct the above errors. After self-alignment procedure, the SINS performs a designed navigation update algorithm in which the velocity and position is damped under stillness situation. Simultaneously, the star tracker measures and outputs the SINS’s navigation angel error. Then, by using SINS’s velocity outputs and star tracker’s angle error outputs as measurements, an integrated coarse alignment algorithm and corresponding fine alignment algorithm was deduced through a designed kalman filter, which could estimate both SINS’s initial navigation errors and IMU’s sensor errors. Simulation result shows that, for a SINS with medium precision, the level and azimuth precision of the integrated alignment algorithm can achieve 2' and 5' respectively.

  6. Mounting Angle between Two Star Trackers in Combined Images Technique%组合星图技术中的双星敏感器安装角度分析

    Institute of Scientific and Technical Information of China (English)

    崔祥祥; 王宏力; 王永胜; 张勇; 何星; 陆敬辉

    2013-01-01

    Generally, two star trackers with small FOV (field-of-view) are used to maintain a high accuracy for micro-satellite’s attitude determination. Due to the small FOV, a sufficient number of stars for identification cannot be always captured. Combined images technique can be used to ease this problem, but its efficiency is highly affected by the mounting angle between two star trackers. The role made by the mounting angle is analyzed and simulated here. Results show that the number of guide starpairs matched to the reference angular distance changes like the sine function as the reference angular distance changes, and it reaches its extremum when the angular distance is about 90 degrees. And it increases as the tolerance increase. The extremum difference of the numbers of guide starpairs is highly affected by the tolerance. Therefore, the mounting angle should not be 90 degrees in combined images technique. The efficiency of the identification is higher as the mounting angle is smaller.%微小卫星一般使用两个小视场星敏感器以实现高精度姿态测量,但小视场容易导致观测星数量不足。组合星图技术可以缓解该问题,但其受星敏感器安装角度影响很大。分析了双星敏感器安装角度对组合星图识别效率的影响,并开展了仿真研究。实验结果表明:角距匹配得到的导航星对个数,随参考星对角距近似呈正弦函数变化,在约90°时达到极值;随容差增大而增大,且容差对导航星对个数极差影响很大。在组合星图技术中,双星敏感器应避免使用90°安装角,且安装角越小,组合星图识别效率越高。

  7. The autonomous vision system on TeamSat

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Riis, Troels

    1999-01-01

    The second qualification flight of Ariane 5 blasted off-the European Space Port in French Guiana on October 30, 1997, carrying on board a small technology demonstration satellite called TeamSat. Several experiments were proposed by various universities and research institutions in Europe and five...... of them were finally selected and integrated into TeamSat, namely FIPEX, VTS, YES, ODD and the Autonomous Vision System, AVS, a fully autonomous star tracker and vision system. This paper gives short overview of the TeamSat satellite; design, implementation and mission objectives. AVS is described in more...... and science data for further ground analysis. AVS successfully determined the attitude and attitude dynamics of TeamSat....

  8. LHCb Upstream Tracker

    CERN Multimedia

    Gandini, Paolo

    2014-01-01

    The LHCb upgrade requires replacing the silicon strip tracker between the vertex locator (VELO) and the magnet. A new design has been developed and tested based on the "stave" concept planned for the ATLAS upgrade.

  9. LHCb Upstream Tracker

    CERN Multimedia

    Gandini, P

    2014-01-01

    The LHCb upgrade requires replacing the silicon strip tracker between the vertex locator (VELO) and the magnet. A new design has been developed and tested based on the "stave" concept planned for the ATLAS upgrade

  10. CMOS APS噪声对星斑质心定位精度的影响%CMOS APS Noise Effect on Position Accuracy of Star Tracker

    Institute of Scientific and Technical Information of China (English)

    史少龙; 尹达一

    2013-01-01

    CCD作为星敏感器探测器的技术已经比较成熟,但其瓶颈限制也日渐显露.本文以IBIS5-B-1300A探测器为例,具体分析CMOS APS各种噪声对星敏感器星像质心定位精度的影响,在理论上分析CMOS探测器所能达到的质心定位精度上限,并通过建模仿真验证理论分析结果,得出弥散斑束腰宽度为0.7,开窗大小为5×5时质心算法精度最高,固定模式噪声(FPN)对质心定位精度影响最大等结论,为星敏感器探测器的选型以及提高系统星点定位精度的潜力提供理论上的依据和支持.%The technology of CCD as a star sensor starlight detector has been very mature,but the bottleneck is becoming exposed.On the basis of parameters of IBIS5-B-1300A,the article analyzes CMOS APS noise effects on position accuracy of star sensor,obtains the maximum star position accuracy which a CMOS APS sensor can achieve and verifies the theoretical analysis results through modeling and simulation.Then two conclusions are drawn.First,when gauss dispersion radius is 0.7 and the windows size is 5 × 5,we can obtain optimized subpixel accuracy; Second,Fixed Pattern Noise(FPN) has the greatest effect on the accuracy of centroid algorithm.This article provides a theoretical basis and support for the selection of the starlight detector for a star sensor system.

  11. A Survey on Star Identification Algorithms

    OpenAIRE

    Daniele Mortari; Benjamin B. Spratling

    2009-01-01

    The author surveys algorithms used in star identification, commonly used in star trackers to determine the attitude of a spacecraft. Star trackers are a staple of attitude determination systems for most types of satellites. The paper covers: (a) lost-in-space algorithms (when no a priori attitude information is available), (b) recursive algorithms (when some a priori attitude information is available), and (c) non-dimensional algorithms (when the star tracker calibration is not well-known). T...

  12. LHCb Upgrade: Upstream Tracker

    CERN Document Server

    AUTHOR|(CDS)2082337

    2015-01-01

    The upgraded LHCb detector will run at an instantaneous luminosity of 2 X 10$^{33}$ cm$^{-2}$ s$^{-1}$, five times higher than in the current configuration, and will have a full 40 MHz readout. In order to cope with these higher instantaneous rates, the tracking detector upstream of the LHCb dipole magnet, called Tracker Turicensis (TT) [1], will be replaced by the Upstream Tracker (UT) [2]. The conceptual design of the UT and the current status of the R&D are presented here.

  13. CMS silicon tracker developments

    International Nuclear Information System (INIS)

    The CMS Silicon tracker consists of 70 m2 of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors

  14. LHCb Silicon Tracker infrastructure

    CERN Document Server

    Ermoline, Yuri

    2004-01-01

    The LHCb Silicon Tracker is a vital part of the experiment. It consists of four planar stations: one trigger and three inner tracking stations. The operation of the Silicon Tracker detectors and electronics is provided by its infrastructure: cooling system, high- and low-voltage power supply systems, temperature and radiation monitoring systems. Several components of these systems are located in the experimental hall and subjected to radiation. This paper mainly concentrates on the recent development: requirements definition, evaluation of possible implementation scenarios, component choice and component radiation tests.

  15. Rotational Dynamics with Tracker

    Science.gov (United States)

    Eadkhong, T.; Rajsadorn, R.; Jannual, P.; Danworaphong, S.

    2012-01-01

    We propose the use of Tracker, freeware for video analysis, to analyse the moment of inertia ("I") of a cylindrical plate. Three experiments are performed to validate the proposed method. The first experiment is dedicated to find the linear coefficient of rotational friction ("b") for our system. By omitting the effect of such friction, we derive…

  16. Teaching Astronomy Using Tracker

    Science.gov (United States)

    Belloni, Mario; Christian, Wolfgang; Brown, Douglas

    2013-01-01

    A recent paper in this journal presented a set of innovative uses of video analysis for introductory physics using Tracker. In addition, numerous other papers have described how video analysis can be a meaningful part of introductory courses. Yet despite this, there are few resources for using video analysis in introductory astronomy classes. In…

  17. LHCb: LHCb Upstream Tracker

    CERN Multimedia

    Manning Jr, P; Stone, S

    2014-01-01

    The LHCb upgrade requires replacing the silicon strip tracker between the vertex locator and the magnet. A new design has been developed and tested based on the "stave" concept planned for the ATLAS upgrade. We will describe the new detector being constructed and show its improved performance in charged particle tracking and triggering.

  18. Two ATLAS trackers become one

    CERN Multimedia

    2006-01-01

    The ATLAS inner detector barrel comes one step closer to completion as the semiconductor tracker is merged with the transition radiation tracker. ATLAS collaborators prepare for the insertion of the semiconductor tracker (SCT, behind) into the transition radiation tracker (TRT, in front). Some had hoped it would fall on Valentine's Day. But despite the slight delay, Friday 17 February was lovingly embraced as 'Conception Day,' when dozens of physicists and engineers from the international collaboration gathered to witness the insertion of the ATLAS semiconductor tracker into the transition radiation tracker, a major milestone in the assembly of the experiment's inner detector. With just millimeters of room for error, the cylindrical trackers were slid into each other as inner detector integration coordinator Heinz Pernegger issued commands and scientists held out flashlights, lay on their backs and stood on ladders to take careful measurements. Each tracker is the result of about 10 years of international ...

  19. MediaTracker system

    International Nuclear Information System (INIS)

    The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can accommodate

  20. Star tracker ground calibration based on the invariant of interstar angles%利用星角距不变性标定星敏感器内部参数

    Institute of Scientific and Technical Information of China (English)

    刘海波; 王文学; 陈圣义; 苏昂; 张小虎

    2014-01-01

    A calibration approach based on the invariant of interstar angles was put forward for star trackers.Compared with common approaches,the sine of interstar angle which provides greater sensitivity for the angle changes closed to 0°was adopted to construct the observation equation instead of its cosine.In the calibration procedure,the two-step approach was proposed to estimate the principal point,focal length,and distortion parameters.The iterative optimization was also proposed to get the optimal estimations.In order to improve the accuracy of calibration, the apparent position of star at the observing time was modified.The experimental results indicate that the sine method is more accurate;and the deviation root-mean-square of the measured interstar angle is 2.2 ×10 -5 rad after calibrated.%提出了一种恒星角距不变的星敏感器内部参数的地面标定方法。较常见的星角距的标定方法不同的是,该方法利用对在0°附近的角度变化较敏感的恒星角距的正弦值建立观测方程;采用两步法分别估计焦距、主点和高阶畸变系数,并采用迭代优化的方法,获得最优估计值。为了确保标定精度,对观测时刻的导航星进行了视位置的修正。实验结果表明,采用星角距的正弦值建立观测方程,估计精度较高,采用考虑高阶畸变的改进正弦法标定后的星角距误差的均方根值为2.2×10-5 rad。

  1. CMS Tracker Visualisation

    CERN Document Server

    Mennea, Maria Santa; Zito, Giuseppe

    2004-01-01

    To provide improvements in the performance of existing tracker data visualization tools in IGUANA, a 2D visualisation software has been developed, using the object oriented paradigm and software engineering techniques. We have designed 2D graphics objects and some of them have been implemented. The access to the new objects is made in ORCA plugin of IGUANA CMS. A new tracker object oriented model has been designed for developing these 2D graphics objects. The model consists of new classes which represent all its components (layers, modules, rings, petals, rods).The new classes are described here. The last part of this document contains a user manual of the software and will be updated with new releases.

  2. LHCb upstream tracker

    CERN Multimedia

    Artuso, Marina

    2016-01-01

    The detector for the LHCb upgrade is designed for 40MHz readout, allowing the experiment to run at an instantaneous luminosity of 2x10^33 cm$^2$s$^-1$. The upgrade of the tracker subsystem in front of the dipole magnet, the Upstream Tracker, is crucial for charged track reconstruction and fast trigger decisions based on a tracking algorithm involving also vertex detector information. The detector consists of 4 planes with a total area of about 8.5m$^2$, made of single sided silicon strip sensors read-out by a novel custom-made ASIC (SALT). Details on the performance of prototype sensors, front-end electronics, near-detector electronics and mechanical components are presented.

  3. The LHCb silicon tracker

    CERN Document Server

    Adeva, B; Bauer, C; Baumeister, D; Bay, A; Bernhard, R P; Bernet, R; Blouw, J; Carron, B; Ermoline, Y; Esperante-Pereira, D; Frei, R; Gassner, J; Hofmann, W; Jiménez-Otero, S; Knöpfle, K T; Köstner, S; Lehner, F; Löchner, S; Lois, C; Needham, M; Pugatch, V; Schmelling, M; Schwingenheuer, B; Siegler, M; Steinkamp, O; Straumann, U; Tran, M T; Vázquez, P; Vollhardt, A; Volyanskyy, D; Voss, H

    2005-01-01

    LHCb is a dedicated B-physics and CP-violation experiment for the Large Hadron Collider at CERN. Efficient track reconstruction and excellent trigger performances are essential in order to exploit fully its physics potential. Silicon strip detectors providing fast signal generation, high resolution and fine granularity are used for this purpose in the large area Trigger Tracker station in front of the spectrometer magnet and the LHCb Inner Tracker covering the area close to the beam pipe behind the magnet. Long read-out strips of up to 38cm are used together with fast signal shaping adapted to the 25ns LHC bunch crossing. The design of these tracking stations, the silicon sensor strip geometries and the latest test results are presented here.

  4. The CMS silicon tracker

    International Nuclear Information System (INIS)

    This paper describes the Silicon microstrip Tracker of the CMS experiment at LHC. It consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 10 000 single-sided equivalent modules have to be built, each one carrying two daisy-chained silicon detectors and their front-end electronics. Back-to-back modules are used to read-out the radial coordinate. The tracker will be operated in an environment kept at a temperature of T=-10 deg. C to minimize the Si sensors radiation damage. Heavily irradiated detectors will be safely operated due to the high-voltage capability of the sensors. Full-size mechanical prototypes have been built to check the system aspects before starting the construction

  5. The CMS silicon tracker

    International Nuclear Information System (INIS)

    The new silicon tracker layout (V4) is presented. The system aspects of the construction are discussed together with the expected tracking performance. Because of the high radiation environment in which the detectors will operate, particular care has been devoted to the study of the characteristics of heavily irradiated detectors. This includes studies on performance (charge collection, cluster size, resolution, efficiency) as a function of the bias voltage, integrated fluence, incidence angle and temperature. (author)

  6. Robust correlation tracker

    Indian Academy of Sciences (India)

    M Sankar Kishore; K Veerabhadra Rao

    2001-06-01

    Correlation tracking plays an important role in the automation of weapon systems. Area correlation is an effective technique for tracking targets that have neither prominent features nor high contrast with the background and the ‘target’ can even be an area or a scene of interest. Even though this technique is robust under varying conditions of target background and light conditions, it has some problems like target drift and false registration. When the tracker or target is moving, the registration point drifts due to the discrete pixel size and aspect angle change. In this research work, an attempt has been made to improve the performance of a correlation tracker for tracking ground targets with very poor contrast. In the present work only the CCD visible images with very poor target to background contrast are considered. Applying novel linear and nonlinear filters, the problems present in the correlation tracker are overcome. Confidence and redundancy measures have been proposed to improve the performance by detecting misregistration. The proposed algorithm is tested on different sequences of images and its performance is satisfactory.

  7. Millisecond X-ray Star Tracker Project

    Data.gov (United States)

    National Aeronautics and Space Administration — CrossTrac Engineering, in cooperation with its subcontractors Dr Suneel Sheikh of ASTER Labs, Inc, and Mr Paul Graven of Cateni, Inc, proposes to develop a next...

  8. The Proba Satellite Star Tracker Performance

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Denver, Troelz; Betto, Maurizio;

    2005-01-01

    ESA's PROBA satellite features a high degree of autonomy, both technologically and scientifically. It is build around a powerful command, data and AOCS controller and with its less than 100 kg it is a true microsatellite. The scientific mission of PROBA includes a scanning telescope, which calls...

  9. Precision High Altitude Star Tracker Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Motivation: The long, successful history of scientific ballooning, coupled with tightening budgets, has led to a surge of interest in the scientific potential of...

  10. A quadrant-CCD star tracker

    Science.gov (United States)

    Clampin, M.; Durrance, S. T.; Barkhouser, R.; Golimowski, D. A.; Wald, A.; Fastie, W. G.; Heidtmann, D. L.; Blouke, Morley M.; Westphal, James A.; Janesick, James R.

    1990-01-01

    The characteristics of a quadrant-CCD designed for pointing and tracking are discussed with reference to its use in an adaptive optics program. The quadrant-CCD is used to correct stellar image motion proceeding from atmospheric turbulence by means of a system in which a sensor measures the image offset and sends data to a high-speed tip/tilt mirror. The design and control of the device are detailed, including four 100-micron-square pixels, the quadrant architecture, controller electronics, and data acquisition computer and interface. The transfer function is set forth in the x and y directions, and transfer curves are shown. A laboratory simulation of random image motion was conducted to evaluate the performance of the quadrant-CCD as an image motion sensor, and the experimental results are presented. The suitability of the quadrant-CCD for space-based pointing and tracking uses is demonstrated by this test and two earlier theoretical studies. Some future developments which improve performance capabilities are mentioned.

  11. CMS tracker visualization tools

    CERN Document Server

    Zito, G; Osborne, I; Regano, A

    2005-01-01

    This document will review the design considerations, implementations and performance of the CMS Tracker Visualization tools. In view of the great complexity of this sub-detector (more than 50 millions channels organized in 16540 modules each one of these being a complete detector), the standard CMS visualization tools (IGUANA and IGUANACMS) that provide basic 3D capabilities and integration within CMS framework, respectively, have been complemented with additional 2D graphics objects. Based on the experience acquired using this software to debug and understand both hardware and software during the construction phase, we propose possible future improvements to cope with online monitoring and event analysis during data taking.

  12. CMS tracker visualization tools

    Energy Technology Data Exchange (ETDEWEB)

    Mennea, M.S. [Dipartimento Interateneo di Fisica ' Michelangelo Merlin' e INFN sezione di Bari, Via Amendola 173 - 70126 Bari (Italy); Osborne, I. [Northeastern University, 360 Huntington Avenue, Boston, MA 02115 (United States); Regano, A. [Dipartimento Interateneo di Fisica ' Michelangelo Merlin' e INFN sezione di Bari, Via Amendola 173 - 70126 Bari (Italy); Zito, G. [Dipartimento Interateneo di Fisica ' Michelangelo Merlin' e INFN sezione di Bari, Via Amendola 173 - 70126 Bari (Italy)]. E-mail: giuseppe.zito@ba.infn.it

    2005-08-21

    This document will review the design considerations, implementations and performance of the CMS Tracker Visualization tools. In view of the great complexity of this sub-detector (more than 50 millions channels organized in 16540 modules each one of these being a complete detector), the standard CMS visualization tools (IGUANA and IGUANACMS) that provide basic 3D capabilities and integration within CMS framework, respectively, have been complemented with additional 2D graphics objects. Based on the experience acquired using this software to debug and understand both hardware and software during the construction phase, we propose possible future improvements to cope with online monitoring and event analysis during data taking.

  13. CMS tracker visualization tools

    Science.gov (United States)

    Mennea, M. S.; Osborne, I.; Regano, A.; Zito, G.

    2005-08-01

    This document will review the design considerations, implementations and performance of the CMS Tracker Visualization tools. In view of the great complexity of this sub-detector (more than 50 millions channels organized in 16540 modules each one of these being a complete detector), the standard CMS visualization tools (IGUANA and IGUANACMS) that provide basic 3D capabilities and integration within CMS framework, respectively, have been complemented with additional 2D graphics objects. Based on the experience acquired using this software to debug and understand both hardware and software during the construction phase, we propose possible future improvements to cope with online monitoring and event analysis during data taking.

  14. CMS tracker visualization tools

    International Nuclear Information System (INIS)

    This document will review the design considerations, implementations and performance of the CMS Tracker Visualization tools. In view of the great complexity of this sub-detector (more than 50 millions channels organized in 16540 modules each one of these being a complete detector), the standard CMS visualization tools (IGUANA and IGUANACMS) that provide basic 3D capabilities and integration within CMS framework, respectively, have been complemented with additional 2D graphics objects. Based on the experience acquired using this software to debug and understand both hardware and software during the construction phase, we propose possible future improvements to cope with online monitoring and event analysis during data taking

  15. Robotics Vision-Based System of Autonomous Underwater Vehicle for an Underwater Pipeline Tracker%自主式水下机器人的光视觉管道探测跟踪系统

    Institute of Scientific and Technical Information of China (English)

    曾文静; 徐玉如; 万磊; 张铁栋

    2012-01-01

    The detection and tracking of underwater pipeline based on monocular vision system of AUV(autonomous underwater vehicle) were addressed.An integrated vision system including software and hardware structure was designed.The feature of underwater pipeline image was analyzed and according to that,corresponding pre-processing method was proposed.An improved Hough transforming was advanced to obtain pipeline contour.Pipeline reference zone was estimated to increase the accuracy and decrease the time cost of pipeline tracking.Finally,the system was validated to be effective and feasible through the tank experiments.%研究了自主式水下机器人(AUV)利用单目光视觉系统对水下管道的检测跟踪问题,对实现该方法的各个过程从硬件组成和软件体系结构两方面进行了阐述,从而完成了一整套水下光视觉系统的软、硬件设计.分析了水下管道图像的特点,结合该特点阐述了图像预处理过程,提出了一种改进的Hough变换方法,改善了管道边界的提取效果.同时采用管道参考区域预测方法,提高了管道的检测率以及实时性,并利用水池试验对系统的可行性和有效性进行了验证.

  16. The ATLAS semiconductor tracker

    CERN Document Server

    Mikuz, Marko

    2003-01-01

    The ATLAS Semiconductor Tracker (SCT) is presented. About 16000 silicon micro-strip sensors with a total active surface of over 60 m **2 and with 6.3 million read-out channels are built into 4088 modules arranged into four barrel layers and nine disks covering each of the forward regions up to an eta of 2.5. Challenges are imposed by the hostile radiation environment with particle fluences up to 2 multiplied by 10**1**4 cm**-**2 1 MeV neutron NIEL equivalent and 100 kGy TID, the 25 ns LHC bunch crossing time and the need for a hermetic, lightweight tracker. The solution adopted is carefully designed strip detectors operated at -7 degree C, biased up to 500 V and read out by binary radhard fast BiCMOS electronics. A zero-CTE carbon fibre structure provides mechanical support. 30 kW of power are supplied on aluminiutn/Kapton tapes and cooled by C//3F//8 evaporative cooling. Data and commands are transferred by optical links. Prototypes of detector modules have been built, irradiated to the maximum expected flue...

  17. The ATLAS Fast Tracker

    CERN Document Server

    Volpi, Guido; The ATLAS collaboration

    2015-01-01

    The use of tracking information at the trigger level in the LHC Run II period is crucial for the trigger an data acquisition (TDAQ) system. The tracking precision is in fact important to identify specific decay products of the Higgs boson or new phenomena, a well as to distinguish the contributions coming from many contemporary collisions that occur at every bunch crossing. However, the track reconstruction is among the most demanding tasks performed by the TDAQ computing farm; in fact, full reconstruction at full Level-1 trigger accept rate (100 KHz) is not possible. In order to overcome this limitation, the ATLAS experiment is planning the installation of a specific processor: the Fast Tracker (FTK), which is aimed at achieving this goal. The FTK is a pipeline of high performance electronic, based on custom and commercial devices, which is expected to reconstruct, with high resolution, the trajectories of charged tracks with a transverse momentum above 1 GeV, using the ATLAS inner tracker information. Patte...

  18. CMS tracker observes muons

    CERN Multimedia

    2006-01-01

    A computer image of a cosmic ray traversing the many layers of the TEC+ silicon sensors. The first cosmic muon tracks have been observed in one of the CMS tracker endcaps. On 14 March, a sector on one of the two large tracker endcaps underwent a cosmic muon run. Since then, thousands of tracks have been recorded. These data will be used not only to study the tracking, but also to exercise various track alignment algorithms The endcap tested, called the TEC+, is under construction at RWTH Aachen in Germany. The endcaps have a modular design, with silicon strip modules mounted onto wedge-shaped carbon fibre support plates, so-called petals. Up to 28 modules are arranged in radial rings on both sides of these plates. One eighth of an endcap is populated with 18 petals and called a sector. The next major step is a test of the first sector at CMS operating conditions, with the silicon modules at a temperature below -10°C. Afterwards, the remaining seven sectors have to be integrated. In autumn 2006, TEC+ wil...

  19. ILC Vertex Tracker R&D

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, Marco; Bussat, Jean-Marie; Contarato, Devis; Denes,Peter; Glesener, Lindsay; Greiner, Leo; Hooberman, Benjamin; Shuman,Derek; Tompkins, Lauren; Vu, Chinh; Bisello, Dario; Giubilato, Piero; Pantano, Devis; Costa, Marco; La Rosa, Alessandro; Bolla, Gino; Bortoletto, Daniela; Children, Isaac

    2007-10-01

    This document summarizes past achievements, current activities and future goals of the R&D program aimed at the design, prototyping and characterization of a full detector module, equipped with monolithic pixel sensors, matching the requirements for the Vertex Tracker at the ILC. We provide a plan of activities to obtain a demonstrator multi-layered vertex tracker equipped with sensors matching the ILC requirements and realistic lightweight ladders in FY11, under the assumption that ILC detector proto-collaborations will be choosing technologies and designs for the Vertex Tracker by that time. The R&D program discussed here started at LBNL in 2004, supported by a Laboratory Directed R&D (LDRD) grant and by funding allocated from the core budget of the LBNL Physics Division and from the Department of Physics at UC Berkeley. Subsequently additional funding has been awarded under the NSF-DOE LCRD program and also personnel have become available through collaborative research with other groups. The aim of the R&D program carried out by our collaboration is to provide a well-integrated, inclusive research effort starting from physics requirements for the ILC Vertex Tracker and addressing Si sensor design and characterization, engineered ladder design, module system issues, tracking and vertex performances and beam test validation. The broad scope of this program is made possible by important synergies with existing know-how and concurrent programs both at LBNL and at the other collaborating institutions. In particular, significant overlaps with LHC detector design, SLHC R&D as well as prototyping for the STAR upgrade have been exploited to optimize the cost per deliverable of our program. This activity is carried out as a collaborative effort together with Accelerator and Fusion Research, the Engineering and the Nuclear Science Divisions at LBNL, INFN and the Department of Physics in Padova, Italy, INFN and the Department of Physics in Torino, Italy and the Department

  20. The CMS Tracker Alignment Strategy

    CERN Document Server

    Weber, Martin

    2006-01-01

    CMS silicon Tracker alignment consists of three key components: Survey during tracker construction, measurements with the Laser Alignment System during operation and track based alignment. Methods and results are explained in detail, with a special focus on track based alignment due to its enormous complexity and numerical challenges.

  1. The LHCb Silicon Tracker

    CERN Document Server

    Bernhard, R P; Bauer, J; Blouw, J; Hofmann, W; Löchner, S; Maciuc, F; Schmelling, M; Smale, N; Schwingenheuer, B; Voss, H; Borysova, M; Ohrimenko, O; Pugatch, V; Yakovenko, V; Bay, A; Bettler, M O; Fauland, P; Frei, R; Nicolas, L; Knecht, M; Perrin, A; Schneider, O; Tran, M T; Van Hunen, J; Vervink, K; Adeva, B; Esperante-Pereira, D; Gallas, A; Fungueirino-Pazos, J L; Lois, C; Pazos-Alvarez, A; Pérez-Trigo, E; Pló-Casasus, M; Vázquez, P; Bernet, R; Gassner, J; Lehner, F; Sakhelashvili, T; Steiner, S; Steinkamp, O; Straumann, U; Van Tilburg, J; Vollhardt, A; Volyanskyy, D; Wenger, A

    2007-01-01

    The Silicon Tracker is a large-surface silicon micro-strip detector that covers the full acceptance of the experiment in a single tracking station upstream of the spectrometer magnet and the inner-most part of the three tracking stations downstream of the magnet. Special emphasis has been put on module quality assurance at all stages of the production. Various tests are performed after each production step and each module goes through several burn-in cycles. The design of the LHCb silicon detectors is described and the main lessons learnt from the R&D phase are summarized. Focus will be on the experience from module production and the quality assurance program.

  2. A silicon tracker for Christmas

    CERN Multimedia

    2008-01-01

    The CMS experiment installed the world’s largest silicon tracker just before Christmas. Marcello Mannelli: physicist and deputy CMS project leader, and Alan Honma, physicist, compare two generations of tracker: OPAL for the LEP (at the front) and CMS for the LHC (behind). There is quite a difference between 1m2 and 205m2.. CMS received an early Christmas present on 18 December when the silicon tracker was installed in the heart of the CMS magnet. The CMS tracker team couldn’t have hoped for a better present. Carefully wrapped in shiny plastic, the world’s largest silicon tracker arrived at Cessy ready for installation inside the CMS magnet on 18 December. This rounded off the year for CMS with a major event, the crowning touch to ten years of work on the project by over five hundred scientists and engineers. "Building a scientific instrument of this size and complexity is a huge technical a...

  3. Mechatronic Prototype of Parabolic Solar Tracker.

    Science.gov (United States)

    Morón, Carlos; Díaz, Jorge Pablo; Ferrández, Daniel; Ramos, Mari Paz

    2016-01-01

    In the last 30 years numerous attempts have been made to improve the efficiency of the parabolic collectors in the electric power production, although most of the studies have focused on the industrial production of thermoelectric power. This research focuses on the application of this concentrating solar thermal power in the unexplored field of building construction. To that end, a mechatronic prototype of a hybrid paraboloidal and cylindrical-parabolic tracker based on the Arduido technology has been designed. The prototype is able to measure meteorological data autonomously in order to quantify the energy potential of any location. In this way, it is possible to reliably model real commercial equipment behavior before its deployment in buildings and single family houses. PMID:27314359

  4. Agent, autonomous

    OpenAIRE

    Luciani, Annie

    2007-01-01

    The expression autonomous agents, widely used in virtual reality, computer graphics, artificial intelligence and artificial life, corresponds to the simulation of autonomous creatures, virtual (i.e. totally computed by a program), or embodied in a physical envelope, as done in autonomous robots.

  5. The CMS Silicon Tracker Alignment

    CERN Document Server

    Castello, R

    2008-01-01

    The alignment of the Strip and Pixel Tracker of the Compact Muon Solenoid experiment, with its large number of independent silicon sensors and its excellent spatial resolution, is a complex and challenging task. Besides high precision mounting, survey measurements and the Laser Alignment System, track-based alignment is needed to reach the envisaged precision.\\\\ Three different algorithms for track-based alignment were successfully tested on a sample of cosmic-ray data collected at the Tracker Integration Facility, where 15\\% of the Tracker was tested. These results, together with those coming from the CMS global run, will provide the basis for the full-scale alignment of the Tracker, which will be carried out with the first \\emph{p-p} collisions.

  6. ATLAS semiconductor tracker installed into its barrel

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    The ATLAS silicon tracker is installed in the silicon tracker barrel. Absolute precision was required in this operation to ensure that the tracker was inserted without damage through minimal clearance. The installation was performed in a clean room on the CERN site so that no impurities in the air would contaminate the tracker's systems.

  7. A Survey on Star Identification Algorithms

    Directory of Open Access Journals (Sweden)

    Daniele Mortari

    2009-01-01

    Full Text Available The author surveys algorithms used in star identification, commonly used in star trackers to determine the attitude of a spacecraft. Star trackers are a staple of attitude determination systems for most types of satellites. The paper covers: (a lost-in-space algorithms (when no a priori attitude information is available, (b recursive algorithms (when some a priori attitude information is available, and (c non-dimensional algorithms (when the star tracker calibration is not well-known. The performance of selected algorithms and supporting algorithms are compared.

  8. CMS Silicon Strip Tracker Monitoring

    CERN Document Server

    Mersi, Stefano

    2010-01-01

    The CMS Silicon Strip Tracker is the largest detector of its kind ever operated, with a silicon surface area of about 200 m$^2$ of silicon surface. The Silicon Strip Tracker it is the sub-detector with the highest number of detector modules within the CMS experiment. Given the complexity of the device, a variety of tools were developed and are used to determine the status of the detector in real time and allow for data qualification and corrective actions when needed. In this paper we describe the monitoring techniques that are used to safely operate the detector and assess the state of its calibration.

  9. Chapter 6: CPV Tracking and Trackers

    Energy Technology Data Exchange (ETDEWEB)

    Luque-Heredia, Ignacio; Magalhaes, Pedro; Muller, Matthew

    2016-04-15

    This chapter explains the functional requirements of a concentrator photovoltaic (CPV) sun tracker. It derives the design specifications of a CPV tracker. The chapter presents taxonomy of trackers describing the most common tracking architectures, based on the number of axes, their relative position, and the foundation and placing of tracking drives. It deals with the structural issues related to tracker design, mainly related to structural flexure and its impact on the system's acceptance angle. The chapter analyzes the auto-calibrated sun tracking control, by describing the state of the art and its development background. It explores the sun tracking accuracy measurement with a practical example. The chapter discusses tracker manufacturing and tracker field works. It reviews survey of different types of tracker designs obtained from different manufacturers. Finally, the chapter deals with IEC62817, the technical standard developed for CPV sun trackers.

  10. Mechanical stability of the CMS Tracker

    CERN Document Server

    CMS Collaboration

    2015-01-01

    reconstructs the absolute position of individual detector modules with a similar accuracy but after days of data taking. During the long term operation at fixed temperature of +4$^o$C in years 2011--2013 the alignment of tracker components was stable within 10 microns. Temperature variations in the Tracker volume are found to cause the displacements of tracker structures of abou...

  11. The CMS silicon strip tracker

    International Nuclear Information System (INIS)

    The Silicon Strip Tracker (SST) is the intermediate part of the CMS Central Tracker System. SST is based on microstrip silicon devices and in combination with pixel detectors and the Microstrip Gas Chambers aims at performing pattern recognition, track reconstruction and momentum measurements for all tracks with pT≥2 GeV/c originating from high luminosity interactions at √s=14 TeV at LHC. We aim at exploiting the advantages and the physics potential of the precise tracking performance provided by the microstrip silicon detectors on a large scale apparatus and in a much more difficult environment than ever. In this paper we describe the actual SST layout and the readout system. (author)

  12. The LHCb Silicon Tracker Project

    Energy Technology Data Exchange (ETDEWEB)

    Agari, M. [Max Planck Institute for Nuclear Physics (Germany); Bauer, C. [Max Planck Institute for Nuclear Physics (Germany); Baumeister, D. [Max Planck Institute for Nuclear Physics (Germany); Blouw, J. [Max Planck Institute for Nuclear Physics (Germany)]. E-mail: Johan.Blouw@mpi-hd.mpg.de; Hofmann, W. [Max Planck Institute for Nuclear Physics (Germany); Knoepfle, K.T. [Max Planck Institute for Nuclear Physics (Germany); Loechner, S. [Max Planck Institute for Nuclear Physics (Germany); Schmelling, M. [Max Planck Institute for Nuclear Physics (Germany); Pugatch, V. [Kiev Institute for Nuclear Research (Ukraine); Bay, A. [Laboratoire de Physique des Hautes Energies, Ecole Polytechnique de Lausanne (France); Carron, B. [Laboratoire de Physique des Hautes Energies, Ecole Polytechnique de Lausanne (France); Frei, R. [Laboratoire de Physique des Hautes Energies, Ecole Polytechnique de Lausanne (France); Jiminez-Otero, S. [Laboratoire de Physique des Hautes Energies, Ecole Polytechnique de Lausanne (France); Tran, M.-T. [Laboratoire de Physique des Hautes Energies, Ecole Polytechnique de Lausanne (France); Voss, H. [Laboratoire de Physique des Hautes Energies, Ecole Polytechnique de Lausanne (France); Adeva, B. [Universidad de Santiago de Compostela (Spain); Esperante, D. [Universidad de Santiago de Compostela (Spain); Lois, C. [Universidad de Santiago de Compostela (Spain); Vasquez, P. [Universidad de Santiago de Compostela (Spain); Bernhard, R.P. [Physik-Insitut Universitaet Zuerich (Switzerland); Bernet, R. [Physik-Insitut Universitaet Zuerich (Switzerland); Ermoline, Y. [Physik-Insitut Universitaet Zuerich (Switzerland); Gassner, J. [Physik-Insitut Universitaet Zuerich (Switzerland); Koestner, S. [Physik-Insitut Universitaet Zuerich (Switzerland); Lehner, F.; Needham, M.; Siegler, M.; Steinkamp, O.; Straumann, U.; Vollhardt, A.; Volyanskyy, D. [Physik-Insitut Universitaet Zuerich (Switzerland)

    2006-01-15

    Two silicon strip detectors, the Trigger Tracker(TT) and the Inner Tracker(Italy) will be constructed for the LHCb experiment. Transverse momentum information extracted from the TT will be used in the Level 1 trigger. The IT is part of the main tracking system behind the magnet. Both silicon detectors will be read out using a custom-developed chip by the ASIC lab in Heidelberg. The signal-over-noise behavior and performance of various geometrical designs of the silicon sensors, in conjunction with the Beetle read-out chip, have been extensively studied in test beam experiments. Results from those experiments are presented, and have been used in the final choice of sensor geometry.

  13. The LHCb Silicon Tracker Project

    International Nuclear Information System (INIS)

    Two silicon strip detectors, the Trigger Tracker(TT) and the Inner Tracker(Italy) will be constructed for the LHCb experiment. Transverse momentum information extracted from the TT will be used in the Level 1 trigger. The IT is part of the main tracking system behind the magnet. Both silicon detectors will be read out using a custom-developed chip by the ASIC lab in Heidelberg. The signal-over-noise behavior and performance of various geometrical designs of the silicon sensors, in conjunction with the Beetle read-out chip, have been extensively studied in test beam experiments. Results from those experiments are presented, and have been used in the final choice of sensor geometry

  14. Introduction to Mini Muon Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Borozdin, Konstantin N. [Los Alamos National Laboratory

    2012-08-13

    Using a mini muon tracker developed at the Los Alamos National Laboratory we performed experiments of simple landscapes of various materials, including TNT, 9501, lead, tungsten, aluminium, and water. Most common scenes are four two inches thick step wedges of different dimensions: 12-inch x 12-inch, 12-inch x 9-inch, 12-inch x 6-inch, and 12-inch x 3-inch; and a one three inches thick hemisphere of lead with spherical hollow, and a similar full lead sphere.

  15. GPS Tracker Data Analysis Platform

    OpenAIRE

    Belay, Tinbit

    2015-01-01

    This thesis work offers GPS tracking solutions which provides detailed reporting on the tracked assets while significantly reducing costs. Despite the fact that GPS trackers are used as a security mechanism. The objective of this thesis was to develop a web platform for gathering the be-havioral aspects of the tracked assets. The thesis work was designed and imple-mented using Groovy-based web application framework, which integrates smooth-ly with the JVM. The user interface was implement...

  16. The CMS tracker control system

    Science.gov (United States)

    Dierlamm, A.; Dirkes, G. H.; Fahrer, M.; Frey, M.; Hartmann, F.; Masetti, L.; Militaru, O.; Shah, S. Y.; Stringer, R.; Tsirou, A.

    2008-07-01

    The Tracker Control System (TCS) is a distributed control software to operate about 2000 power supplies for the silicon modules of the CMS Tracker and monitor its environmental sensors. TCS must thus be able to handle about 104 power supply parameters, about 103 environmental probes from the Programmable Logic Controllers of the Tracker Safety System (TSS), about 105 parameters read via DAQ from the DCUs in all front end hybrids and from CCUs in all control groups. TCS is built on top of an industrial SCADA program (PVSS) extended with a framework developed at CERN (JCOP) and used by all LHC experiments. The logical partitioning of the detector is reflected in the hierarchical structure of the TCS, where commands move down to the individual hardware devices, while states are reported up to the root which is interfaced to the broader CMS control system. The system computes and continuously monitors the mean and maximum values of critical parameters and updates the percentage of currently operating hardware. Automatic procedures switch off selected parts of the detector using detailed granularity and avoiding widespread TSS intervention.

  17. Activity trackers: a critical review.

    Science.gov (United States)

    Lee, Jeon; Finkelstein, Joseph

    2014-01-01

    The wearable consumer health devices can be mainly divided into activity trackers, sleep trackers, and stress management devices. These devices are widely advertised to provide positive effects on the user's daily behaviours and overall heath. However, objective evidence supporting these claims appears to be missing. The goal of this study was to review available evidence pertaining to performance of activity trackers. A comprehensive review of available information has been conducted for seven representative devices and the validity of marketing claims was assessed. The device assessment was based on availability of verified output metrics, theoretical frameworks, systematic evaluation, and FDA clearance. The review identified critical absence of supporting evidence of advertised functions and benefits for the majority of the devices. Six out of seven devices did not provide any information on sensor accuracy and output validity at all. Possible underestimation or overestimation of specific health indicators reported to consumers was not clearly disclosed to the public. Furthermore, significant limitations of these devices which can be categorized into user restrictions, user responsibilities and company disclaimers could not be easily found or comprehended by unsophisticated users and may represent a serious health hazard. PMID:25160247

  18. GigaTracker, the NA62 Beam Tracker

    CERN Document Server

    Velghe, Bob; Bonacini, Sandro; Ceccucci, Augusto; Degrange, Jordan; Kaplon, Jan; Kluge, Alexander; Mapelli, Alessandro; Morel, Michel; Noël, Jérôme; Noy, Matthew; Perktold, Lukas; Petagna, Paolo; Poltorak, Karolina; Riedler, Petra; Romagnoli, Giulia; Chiozzi, Stefano; Ramusino, Angelo Cotta; Fiorini, Massimiliano; Gianoli, Alberto; Petrucci, Ferruccio; Wahl, Heinrich; Arcidiacono, Roberta; Jarron, Pierre; Marchetto, Flavio; Gil, Eduardo Cortina; Nuessle, Georg; Szilasi, Nicolas

    2015-01-01

    The GigaTracker measures the momentum, the direction and the crossing time of all the NA62 secondary beam particles. It is composed of three hybrid silicon pixel stations and four achromatic magnets. All the stations have a rate capability above 750 MHz, a single hit time resolution better than 200 ps and a thickness less than 0.5 % of X = X 0 . The stations’ sensor is read out by ten custom TDCpix ASICs. An innovative microchannel cooling solution is used to keep the sensor temperature below 0 °C. The stations are operated in vacuum and are easily swappable

  19. Adaptive Visual Face Tracking for an Autonomous Robot

    NARCIS (Netherlands)

    van Hoof, Herke; van der Zant, Tijn; Wiering, Marco

    2011-01-01

    Perception is an essential ability for autonomous robots in non-standardized conditions. However, the appearance of objects can change between different conditions. A system visually tracking a target based on its appearance could lose its target in those cases. A tracker learning the appearance of

  20. GigaTracker, a Thin and Fast Silicon Pixels Tracker

    CERN Document Server

    Velghe, Bob; Bonacini, Sandro; Ceccucci, Augusto; Kaplon, Jan; Kluge, Alexander; Mapelli, Alessandro; Morel, Michel; Noël, Jérôme; Noy, Matthew; Perktold, Lukas; Petagna, Paolo; Poltorak, Karolina; Riedler, Petra; Romagnoli, Giulia; Chiozzi, Stefano; Cotta Ramusino, Angelo; Fiorini, Massimiliano; Gianoli, Alberto; Petrucci, Ferruccio; Wahl, Heinrich; Arcidiacono, Roberta; Jarron, Pierre; Marchetto, Flavio; Gil, Eduardo Cortina; Nuessle, Georg; Szilasi, Nicolas

    2014-01-01

    GigaTracker, the NA62’s upstream spectrometer, plays a key role in the kinematically constrained background suppression for the study of the K + ! p + n ̄ n decay. It is made of three independent stations, each of which is a six by three cm 2 hybrid silicon pixels detector. To meet the NA62 physics goals, GigaTracker has to address challenging requirements. The hit time resolution must be better than 200 ps while keeping the total thickness of the sensor to less than 0.5 mm silicon equivalent. The 200 μm thick sensor is divided into 18000 300 μm 300 μm pixels bump-bounded to ten independent read-out chips. The chips use an end-of-column architecture and rely on time-over- threshold discriminators. A station can handle a crossing rate of 750 MHz. Microchannel cooling technology will be used to cool the assembly. It allows us to keep the sensor close to 0 C with 130 μm of silicon in the beam area. The sensor and read-out chip performance were validated using a 45 pixel demonstrator with a laser test setu...

  1. OptoTracker project proposal

    OpenAIRE

    Celentano, A.

    2016-01-01

    The project OptoTracker aims to investigate a new approach to track charged particles in a scintillating material, by using the optical signal. Our idea is to reconstruct the trajectory of a charged particle by collecting the scintillation light emitted along the path with pixelized photo-detectors. This would permit to obtain an image of the track, similarly to what is done in a photographic camera. Full 3D reconstruction is performed by using both the charge distribution and the hit time in...

  2. Development of a digital mobile solar tracker

    OpenAIRE

    Baidar, Sunil; Kille, Natalie; Ortega, Ivan; Sinreich, Roman; Thomson, David; Hannigan, James; Volkamer, Rainer

    2016-01-01

    We have constructed and deployed a fast digital solar tracker aboard a moving ground-based platform. The tracker consists of two rotating mirrors, a lens, an imaging camera, and a motion compensation system that provides the Euler angles of the mobile platform in real time. The tracker can be simultaneously coupled to UV–Vis and Fourier transform infrared spectrometers, making it a versatile tool to measure the absorption of trace gases using solar incoming radiation. The in...

  3. Development of a digital mobile solar tracker

    OpenAIRE

    S. Baidar; N. Kille; I. Ortega; R. Sinreich; Thomson, D.; Hannigan, J.; R. Volkamer

    2015-01-01

    We have constructed and deployed a fast digital solar tracker aboard a moving ground-based platform. The tracker consists of two rotating mirrors, a lens, an imaging camera, and a motion compensation system that provides the Euler angles of the mobile platform in real time. The tracker can be simultaneously coupled to UV-Vis and FTIR spectrometers making it a versatile tool to measure the absorption of trace gases using solar incoming radi...

  4. A Novel Approach for Star Extraction from Star Image

    Institute of Scientific and Technical Information of China (English)

    ZHENGSheng; LIUJian; TIANJinwen; YANGRuijuan

    2005-01-01

    Star acquisition is one of the most timeconsuming routines in star tracker operation. One star Point spread function (PSF) forms a near Gaussian distribution in the star image, the star image can be regarded as 2-D intensity surface, and every pixel is the sampled point. The star cluster grouping is to find the highes tintensity pixel among the PSFs and collect the adjacent pixels and group them. The possible highest intensity pixels are the maximum extremum points of the 2-D intensity surface. To efficiently extract star from the star image, a novel star acquisition approach, which uses the simplified least squares support vector machines regression algorithm to find the optimal intensity surface function and predictthe maximum extremum points, is proposed. Comput erexperiments are carried out for the simulated star images.The experimental results demonstrate that the proposed method has a lot of advantages, including the high efficiency and good robustness over a wide range of sensor noise.

  5. The ATLAS semiconductor tracker (SCT)

    CERN Document Server

    Jackson, J N

    2005-01-01

    The ATLAS detector (CERN/LHCC/94-43 (1994)) is designed to study a wide range of physics at the CERN Large Hadron Collider (LHC) at luminosities up to 10**3**4 cm**-**2 s**-**1 with a bunch-crossing rate of 40 MHz. The Semiconductor Tracker (SCT) forms a key component of the Inner Detector (vol. 1, ATLAS TDR 4, CERN/LHCC 97-16 (1997); vol. 2, ATLAS TDR 5, CERN/LHCC 97-17 (1997)) which is situated inside a 2 T solenoid field. The ATLAS Semiconductor Tracker (SCT) utilises 4088 silicon modules with binary readout mounted on carbon fibre composite structures arranged in the forms of barrels in the central region and discs in the forward region. The construction of the SCT is now well advanced. The design of the SCT modules, services and support structures will be briefly outlined. A description of the various stages in the construction process will be presented with examples of the performance achieved and the main difficulties encountered. Finally, the current status of the construction is reviewed.

  6. Upgrade of the CMS tracker

    CERN Document Server

    Tricomi, Alessia

    2014-01-01

    The LHC machine is planning an upgrade program which will smoothly bring the luminosity up to or above $5\\times 10^{34}$ cm$^{-2}$s$^{-1}$ sometimes after 2020, to eventually reach an integrated luminosity of 3000 fb$^{-1}$ at the end of that decade. The foreseen increases of both the instantaneous and the integrated luminosity by the LHC during the next ten years will necessitate a stepwise upgrade of the CMS tracking detector. During the extended end-of-year shutdown 2016-2017 the pixel detector will be exchanged with a new one. The so-called Phase1 Pixel foresees one additional barrel layer and one additional end-cap disk, a new readout chip, reduction of material, and the installation of more efficient cooling and powering systems. In the so-called Phase2, when LHC will reach the High Luminosity (HL-LHC) phase, CMS will need a completely new Tracker detector, in order to fully exploit the high-demanding operating conditions and the delivered luminosity. The new Tracker should have also trigg...

  7. 无热化大相对孔径星敏感器光学系统设计%Optical System Design of Light Star Tracker with Low F-number

    Institute of Scientific and Technical Information of China (English)

    汤天瑾

    2011-01-01

    提出了一种大相时孔径轻小型光学系统的设计方案,给出了设计方案及热分析结果.光学系统工作谱段500~800nm,视场角9°,相对孔径1/1.2,光学系统设计结果良好,弥散斑直径在两个像元尺寸之内,能够满足光学系统对能量集中度和弥散斑的要求.基于光学热补偿理论对光学系统进行了无热化分析和消热设计.通过分析不同温度下的传递函数和能量集中度曲线,可以看出在-10℃~40℃温度范围内系统性能稳定,基本实现无热化.%The Paper presents an optical system design of light CCD star sensor with low F-number, and atermalization is also done based on the compensation theory of thermal dispersion,giving the design and thermo-optical analysis results. The lens system is composed of seven lens which has an F-number of F/1.2, a field of view of 9 degrees, and a working wavelength range of 500~800nm.The geometric spot dispersed in two pixels at its focal surface, which can satisfied the requirement of the encircled energy and spot dispersion. The encircled energy and modulation transfer function of the lens at different temperatures are given as examples , It shows that the athermal optical system can work steadily within the temperature range of ~10℃~40℃.

  8. CMS Tracker Integration: monitoring the process quality

    International Nuclear Information System (INIS)

    The CMS experiment at LHC features the largest Silicon Strip Tracker (SST) ever built. This detector is composed of about 15000 modules, thus the potential problems of the system comes from its complexity. This article covers the tests performed during the tracker integration, describing their motivations in terms of process quality assurance

  9. OptoTracker project proposal

    CERN Document Server

    Celentano, A

    2016-01-01

    The project OptoTracker aims to investigate a new approach to track charged particles in a scintillating material, by using the optical signal. Our idea is to reconstruct the trajectory of a charged particle by collecting the scintillation light emitted along the path with pixelized photo-detectors. This would permit to obtain an image of the track, similarly to what is done in a photographic camera. Full 3D reconstruction is performed by using both the charge distribution and the hit time information folded in a sophisticated reconstruction algorithm. This solution, compared to "traditional" tracking methods, exploits the fastest information carrier within a material: the light. Therefore, an optical tracking detector would be intrinsically capable of sustaining a very high interaction rate. Moreover, the intrinsic resolution would not be limited by carriers diffusion, as happens in charge-transport based detectors. This new technology could have a very large impact both on beam experiments, thanks to the po...

  10. Silicon photomultipliers for scintillating trackers

    Energy Technology Data Exchange (ETDEWEB)

    Rabaioli, S., E-mail: simone.rabaioli@gmail.com [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); Berra, A.; Bolognini, D. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Bonvicini, V. [INFN sezione di Trieste (Italy); Bosisio, L. [Universita degli Studi di Trieste and INFN sezione di Trieste (Italy); Ciano, S.; Iugovaz, D. [INFN sezione di Trieste (Italy); Lietti, D. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Penzo, A. [INFN sezione di Trieste (Italy); Prest, M. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Rashevskaya, I.; Reia, S. [INFN sezione di Trieste (Italy); Stoppani, L. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); Vallazza, E. [INFN sezione di Trieste (Italy)

    2012-12-11

    In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain ({approx}10{sup 6}). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

  11. Silicon photomultipliers for scintillating trackers

    Science.gov (United States)

    Rabaioli, S.; Berra, A.; Bolognini, D.; Bonvicini, V.; Bosisio, L.; Ciano, S.; Iugovaz, D.; Lietti, D.; Penzo, A.; Prest, M.; Rashevskaya, I.; Reia, S.; Stoppani, L.; Vallazza, E.

    2012-12-01

    In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain (∼106). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

  12. Ruby on Rails Issue Tracker

    Science.gov (United States)

    Rodriguez, Juan Jared

    2014-01-01

    The purpose of this report is to detail the tasks accomplished as a NASA NIFS intern for the summer 2014 session. This internship opportunity is to develop an issue tracker Ruby on Rails web application to improve the communication of developmental anomalies between the Support Software Computer Software Configuration Item (CSCI) teams, System Build and Information Architecture. As many may know software development is an arduous, time consuming, collaborative effort. It involves nearly as much work designing, planning, collaborating, discussing, and resolving issues as effort expended in actual development. This internship opportunity was put in place to help alleviate the amount of time spent discussing issues such as bugs, missing tests, new requirements, and usability concerns that arise during development and throughout the life cycle of software applications once in production.

  13. Autonomous Search

    CERN Document Server

    Hamadi, Youssef; Saubion, Frédéric

    2012-01-01

    Decades of innovations in combinatorial problem solving have produced better and more complex algorithms. These new methods are better since they can solve larger problems and address new application domains. They are also more complex which means that they are hard to reproduce and often harder to fine-tune to the peculiarities of a given problem. This last point has created a paradox where efficient tools are out of reach of practitioners. Autonomous search (AS) represents a new research field defined to precisely address the above challenge. Its major strength and originality consist in the

  14. Pure Autonomic Failure

    Science.gov (United States)

    ... Drugs GARD Information Navigator FAQs About Rare Diseases Pure autonomic failure Title Other Names: Bradbury Eggleston syndrome; ... Categories: Nervous System Diseases ; RDCRN Summary Summary Listen Pure autonomic failure is characterized by generalized autonomic failure ...

  15. The D0 silicon microstrip tracker

    CERN Document Server

    Quinn, B

    2003-01-01

    The D0 collaboration has completed building a 793,000 channel silicon microstrip tracker for the D0 upgrade. The tracker consists of 768 ladder and wedge assemblies including both single- and double-sided detectors. Detector readout utilizes the SVX-IIE radiation hard chip with on-chip digitization and sparsification. A brief review of the detector design is presented along with results from the assembly and testing processes. The operation of the full readout chain and the performance of the silicon tracker are described. Finally, lessons for future production of large scale tracking systems are discussed.

  16. The Silicon Tracker of the LHCb experiment

    CERN Document Server

    Köstner, S; Agari, M; Bauer, C; Baumeister, D; Bay, A; Bernhard, R P; Bernet, R; Blouw, J; Carron, B; Ermoline, Y; Esperante-Pereira, D; Frei, R; Gassner, J; Hofmann, W; Jiménez-Otero, S; Knöpfle, K T; Lehner, F; Löchner, S L; Lois, C; Needham, M; Perron, A; Pugatch, V; Schmelling, M; Schwingenheuer, B; Siegler, M; Steinkamp, O; Straumann, U; Tran, M T; Vazques, P; Vollhardt, A; Volyanskyy, D; Voss, H

    2004-01-01

    LHCb is one of the experiments of the Large Hadron Collider at CERN, dedicated to B-physics and CP-violation measurements. To fully exploit the physics potential, a good tracking performance with high efficiency in a high particle density environment close to the beam pipe is required. Silicon strip detectors with large read-out pitch and long strips will be used for the LHCb Inner Tracker after the magnet and the Trigger Tracker station in front of the magnet. We report here about the design of the Silicon Tracker, test beam results and the electrical tests foreseen during module production.

  17. ATLAS Fast Tracker Simulation Challenges

    CERN Document Server

    Adelman, Jahred; The ATLAS collaboration; Borodin, Mikhail; Chakraborty, Dhiman; García Navarro, José Enrique; Golubkov, Dmitry; Kama, Sami; Panitkin, Sergey; Smirnov, Yuri; Stewart, Graeme; Tompkins, Lauren; Vaniachine, Alexandre; Volpi, Guido

    2015-01-01

    To deal with Big Data flood from the ATLAS detector most events have to be rejected in the trigger system. the trigger rejection is complicated by the presence of a large number of minimum-bias events – the pileup. To limit pileup effects in the high luminosity environment of the LHC Run-2, ATLAS relies on full tracking provided by the Fast TracKer (FTK) implemented with custom electronics. The FTK data processing pipeline has to be simulated in preparation for LHC upgrades to support electronics design and develop trigger strategies at high luminosity. The simulation of the FTK - a highly parallelized system - has inherent performance bottlenecks on general-purpose CPUs. To take advantage of the Grid Computing power, the FTK simulation is integrated with Monte Carlo simulations at the Production System level above the ATLAS workload management system PanDA. We report on ATLAS experience with FTK simulations on the Grid and next steps for accommodating the growing requirements for resources during the LHC R...

  18. The LHCb Upstream Tracker Project

    CERN Document Server

    Steinkamp, Olaf

    2015-01-01

    The LHCb detector performs searches for New Physics in CP-violating observables and rare heavy-quark decays at the LHC. A comprehensive upgrade is planned for the long shutdown of the LHC in 2018/19. A goal of this upgrade is to abolish hardware triggers and read out the full detector at 40 MHz. This requires to replace the existing TT station upstream of the LHCb magnet by a new silicon micro-strip detector, the Upstream Tracker (UT). The UT will have a new front-end chip compatible with 40 MHz readout, silicon sensors with improved radiation hardness, finer readout granularity, and improved acceptance coverage at small polar angles. The outer region of each detection layer will be covered by p-in-n sensors with 10 cm long strips and a pitch of about 180 mum, while n-in-p sensors with half the pitch and strip length will be employed in the regions of highest particle density close to the beam pipe. The innermost sensors will have a circular cutout to optimize the forward acceptance. The front-end chip is bei...

  19. CMS Silicon Strip Tracker Operation

    CERN Document Server

    Gotra, Yuri

    2010-01-01

    The CMS Silicon Strip Tracker (SST), comprising 9.6 million readout channels from 15148 modules covering an area of about 200 square meters, needs to be precisely calibrated in order to correctly interpret and reconstruct the events recorded from the detector, ensuring that the SST performance fully meets the physics research program of the CMS experiment. Calibration constants may be derived from promptly reconstructed events as well as from pedestal runs gathered just before the acquisition of physics runs. These calibration procedures were exercised in summer and winter 2009, when the CMS detector was commissioned using cosmic muons and proton-proton collisions at a center-of-mass energies of 900 GeV and 2.36 TeV. During these data taking periods the performance of the SST was carefully studied: the noise of the detector, the data integrity, the signal-to-noise ratio, the hit reconstruction efficiency, the calibration workflows have been all checked for stability and for different conditions, at the module...

  20. ATLAS Silicon Microstrip Tracker Operation

    CERN Document Server

    Berglund, E; The ATLAS collaboration

    2009-01-01

    The ATLAS experiment at the CERN Large Hadron Collider (LHC) has started taking data last autumn with the inauguration of the LHC. The SemiConductor Tracker (SCT) is the key precision tracking device in ATLAS, made up from silicon micro-strip detectors processed in the planar p-in-n technology. The completed SCT has been installed inside the ATLAS experimental hall. Since then the detector was operated for many months under realistic conditions. Calibration data has been taken and analyzed to determine the noise performance of the system. In addition, extensive commissioning with cosmic ray events has been performed both with and without magnetic field. The cosmic muon data has been used to align the detector, to check the timing of the front-end electronics as well as to measure the hit efficiency of modules. The sensor behavior in magnetic field was studied by measurements of the Lorentz angle. For the initial running with unfocused LHC beam operation with undepleted sensors is foreseen. Efficiency and nois...

  1. The silicon drift vertex detector for the STAR experiment at RHIC

    CERN Document Server

    Pandey, S U; Beuttenmüller, Rolf H; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Elliot, D; Eremin, V; Grau, M; Hoffmann, G W; Humanic, T; Ilyashenko, Yu S; Kotov, I; Kraner, H W; Kuczewski, P; Leonhardt, B; Li, Z; Liaw, C J; Lo Curto, G; Middelkamp, P; Minor, R; Munhoz, M; Ott, G; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Soja, B; Sugarbaker, E R; Takahashi, J; Wilson, K; Wilson, R

    2002-01-01

    The current status of the STAR Silicon Vertex Tracker (SVT) is presented. The performance of the Silicon Drift Detectors (SDD) is discussed. Results for a recent 15 layer SDD tracker which prototypes all components of the SVT are presented. The enhanced physics capabilities of the STAR detector due to the addition of the SVT are addressed.

  2. Power Studies for the CMS Pixel Tracker

    International Nuclear Information System (INIS)

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R and D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  3. Power distribution studies for CMS forward tracker

    International Nuclear Information System (INIS)

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R and D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  4. Incremental LSTM-based Dialog State Tracker

    OpenAIRE

    Zilka, Lukas; Jurcicek, Filip

    2015-01-01

    A dialog state tracker is an important component in modern spoken dialog systems. We present an incremental dialog state tracker, based on LSTM networks. It directly uses automatic speech recognition hypotheses to track the state. We also present the key non-standard aspects of the model that bring its performance close to the state-of-the-art and experimentally analyze their contribution: including the ASR confidence scores, abstracting scarcely represented values, including transcriptions i...

  5. Work on the ATLAS semiconductor tracker barrel

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    Precision work is performed on the semiconductor tracker barrel of the ATLAS experiment. All work on these delicate components must be performed in a clean room so that impurities in the air, such as dust, do not contaminate the detector. The semiconductor tracker will be mounted in the barrel close to the heart of the ATLAS experiment to detect the path of particles produced in proton-proton collisions.

  6. Design and manufacture of a Solar Tracker

    OpenAIRE

    Domínguez Marzo, Hugo

    2014-01-01

    This project pretends to be a document that includes all the process of design and manufacture of a solar tracker. The solar tracker has its performance divided in three main parts; the first that gets information from the exterior. This project explains how the sensors that get the external information are chosen, the materials which are made of and how are they positioned. The second part, which analyses and process this information is done through a microcontroller, the document also in...

  7. Last ATLAS transition radiation tracker module installed

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    The ATLAS transition radiation tracker consists of 96 modules and will join the pixel detector and silicon tracker at the heart of the experiment to map the trajectories of particles and identify electrons produced when proton beams collide. In the last image the team responsible for assembly are shown from left to right: Kirill Egorov (Petersburg Nuclear Physics Institute), Pauline Gagnon (Indiana University), Ben Legeyt (University of Pennsylvania), Chuck Long (Hampton University), John Callahan (Indiana University) and Alex High (University of Pennsylvania).

  8. Search for tracker potentials in quintessence theory

    Science.gov (United States)

    Johri, Vinod B.

    2002-12-01

    We report a significant finding in quintessence theory that scalar fields with tracker potentials have a model-independent scaling behaviour in the expanding universe. So far, widely discussed exponential, power law or hyperbolic potentials can simply mimic the tracking behaviour over a limited range of redshift. A new version of the tracker field theory is proposed and it is shown that in the small redshift range where the variation of the tracking parameter ɛ may be taken to be negligible, the differential equation of generic potentials leads to hyperbolic sine and hyperbolic cosine potentials which may approximate a tracker field in the present-day universe. We have plotted the variation of the tracker potential and the equation of state of the tracker field as a function of the redshift z for the model-independent relation derived from tracker field theory; we have also plotted the variation of V(Φ) in terms of the scalar field Φ for the chosen hyperbolic cosine function and have compared it with the curves obtained by the reconstruction of V(Φ) from real observational data from the supernovae.

  9. Measurements of strangeness production in the STAR experiment at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, W.K. [Wayne State Univ., Detroit, MI (United States)

    1995-07-15

    Simulations of the ability of the STAR (Solenoidal Tracker at RHIC) detector to measure strangeness production in central Au+Au collisions at RHIC are presented. Emphasis is placed on the reconstruction of short lived particles using a high resolution inner tracker. The prospects for performing neutral kaon interferometry are discussed. Simulation results for measurements of strange and multi-strange baryons are presented.

  10. Measurement of charm flow with the STAR Heavy Flavour Tracker

    Czech Academy of Sciences Publication Activity Database

    Xu, Z.; Kushpil, Vasilij; Šumbera, Michal

    2006-01-01

    Roč. 32, č. 12 (2006), S571-S574. ISSN 0954-3899 R&D Projects: GA ČR GA202/04/0793 Institutional research plan: CEZ:AV0Z10480505 Keywords : RHIC Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.781, year: 2006

  11. Angular-Rate Estimation using Star Tracker Measurements

    Science.gov (United States)

    Azor, R.; Bar-Itzhack, Itzhack Y.; Deutschmann, Julie K.; Harman, Richard R.

    1999-01-01

    This paper presents algorithms for estimating the angular-rate vector of satellites using quaternion measurements. Two approaches are compared, one that uses differentiated quaternion measurements to yield coarse rate measurements which are then fed into two different estimators. In the other approach the raw quaternion measurements themselves are fed directly into the two estimators. The two estimators rely on the ability to decompose the non-linear rate dependent part of the rotational dynamics equation of a rigid body into a product of an angular-rate dependent matrix and the angular-rate vector itself. This decomposition, which is not unique, enables the treatment of the nonlinear spacecraft dynamics model as a linear one and, consequently, the application of a Pseudo-Linear Kalman Filter (PSELIKA). It also enables the application of a special Kalman filter which is based on the use of the solution of the State Dependent Algebraic Riccati Equation (SDARE) in order to compute the Kalman gain matrix and thus eliminates the need to propagate and update the filter covariance matrix. The replacement of the elaborate rotational dynamics by a simple first order Markov model is also examined. In this paper a special consideration is given to the problem of delayed quaternion measurements. Two solutions to this problem are suggested and tested. Real Rossi X-Ray Timing Explorer (RXTE) data is used to test these algorithms, and results of these tests are presented.

  12. Star Pattern Recognition for Attitude Determination using Genetic Algorithms

    OpenAIRE

    Paladugu, Lalitha; Williams, Brian,; Schoen, Marco

    2003-01-01

    This paper presents a study using Genetic Algorithms (GA) to solve the star pattern recognition problem associated with star tracker attitude determination systems. Characteristics of the stars that are visible within the Field of View (FOV) of an imager are defined with regard to relative distances and angles. The proposed GA minimizes the discrepancy between the characteristics of the stars inside the actual FOV and a candidate FOV selected from the star map in order to determine the inerti...

  13. LEO AUTONOMOUS NAVIGATION BASED ON IMAGE MOTION

    Institute of Scientific and Technical Information of China (English)

    DUANFang; LIUJian-ye; YUFeng

    2005-01-01

    A method of LEO autonomous navigation is presented based on the nonlinear satellite velocity relative to the earth. The velocity is detected by a high-speed camera, with the attitude information detected by a star sensor. Compared with traditional autonomous navigation by landmark identification, the satellite velocity relarive to the earth is obtained by correlativity analysis of images. It does not need to recognize ground objects or views. Since it is not necessary to pre-store the database of ground marks, lots of memory space can be saved.The state and observation equations are constructed, and the filtering is processed by the Kalman filter. Simulation results show that the system has high autonomous navigation precision in LEO autonomous navigation.

  14. Search for Tracker Potentials in Quintessence Theory

    CERN Document Server

    Johri, V B

    2002-01-01

    We report a significant finding in Quintessence theory that the the scalar fields with tracker potentials have a model-independent scaling behaviour in the expanding universe. So far widely discussed exponential,power law or hyperbolic potentials can simply mimic the tracking behaviour over a limited range of redshift. In the small redshift range where the variation of the tracking parameter $\\epsilon$ may be taken to be negligible, the differential equation of generic potentials leads to hyperbolic sine and hyperbolic cosine potentials which may approximate tracker field in the present day universe. We have plotted the variation of tracker potential and the equation of state of the tracker field as function of the redshift $z$ for the model-independent relation derived from tracker field theory; we have also plotted the variation of $V(\\Phi)$ in terms of the scalar field $\\Phi$ for the chosen hyperbolic cosine function and have compared with the curves obtained by reconstruction of $V(\\phi)$ from the real ob...

  15. CMS tracker slides into centre stage

    CERN Multimedia

    2006-01-01

    As preparations for the magnet test and cosmic challenge get underway, a prototype tracker has been carefully inserted into the centre of CMS. The tracker, in its special platform, is slowly inserted into the centre of CMS. The CMS prototype tracker to be used for the magnet test and cosmic challenge coming up this summer has the same dimensions -2.5 m in diameter and 6 m in length- as the real one and tooling exactly like it. However, the support tube is only about 1% equipped, with 2 m2 of silicon detectors installed out of the total 200 m2. This is already more than any LEP experiment ever used and indicates the great care needed to be taken by engineers and technicians as these fragile detectors were installed and transported to Point 5. Sixteen thousand silicon detectors with a total of about 10 million strips will make up the full tracker. So far, 140 modules with about 100 000 strips have been implanted into the prototype tracker. These silicon strips will provide precision tracking for cosmic muon...

  16. Construction of the CMS silicon strip tracker

    International Nuclear Information System (INIS)

    In the last year the CMS experiment has constructed and integrated the largest ever build full Silicon Strip Tracker. The CMS Tracker collaboration set up a unique scheme of quality control to ensure the necessary high quality of all of the 15,148 modules and their super structures. The applied scheme of quality control revealed several problems, which escaped the initial R and D phase, ranging from corrosion effects on the silicon, capton and via problems on the front end hybrids up to aging conductive glue connections. An overview of the construction and qualification experience is given, discussing the major steps which result in the unique experimental device, which the CMS Tracker is currently commissioning

  17. The NA62 GigaTracker

    CERN Document Server

    Perrin-Terrin, Mathieu

    2015-01-01

    The GigaTracker is an hybrid silicon pixel detector built for the NA62 experiment aiming at measuring the branching fraction of the ultra-rare kaon decay K + ! p + n ̄ n at the CERN SPS. The detector has to track particles in a beam with a flux reaching 1.3 MHz/mm 2 and provide single-hit timing with 200ps RMS resolution for a total material budget of less than 1.5 X 0 . The tracker comprises three 60.8mm 27mm stations installed in vacuum ( 10 ...

  18. The CMS tracker and its performance

    International Nuclear Information System (INIS)

    The compact muon solenoid CMS is one of the two general purpose detectors planned at the large hadron collider at CERN. The main physics goals of CMS include the search for the Higgs boson, for signs beyond the standard model and an accurate measurement of CP violation in the b-system. These goals and the hostile radiation environment at the LHC represent a challenge for the tracker which will utilise a system of silicon pixel detectors, silicon strip detectors and microstrip gas chambers. The design of the tracker and its performance in selected aspects of b-physics are presented in this paper. (orig.)

  19. Autonomous Real Time Requirements Tracing

    Science.gov (United States)

    Plattsmier, George; Stetson, Howard

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  20. Autonomic Nervous System Disorders

    Science.gov (United States)

    Your autonomic nervous system is the part of your nervous system that controls involuntary actions, such as the beating of your heart ... breathing and swallowing Erectile dysfunction in men Autonomic nervous system disorders can occur alone or as the result ...

  1. Autoimmune Autonomic Ganglionopathy

    Science.gov (United States)

    ... Accessed 9/2/2015. Autoimmune Autonomic Ganglionopathy Summary. Dysautonomia International . http://www.dysautonomiainternational.org/page.php?ID= ... page Basic Information In Depth Information Basic Information Dysautonomia International offers an information page on Autoimmune autonomic ...

  2. System for star catalog equalization to enhance attitude determination

    Science.gov (United States)

    Liu, Yong (Inventor); Wu, Yeong-Wei Andy (Inventor); Li, Rongsheng (Inventor)

    2001-01-01

    An apparatus for star catalog equalization to enhance attitude determination includes a star tracker, a star catalog and a controller. The star tracker is used to sense the positions of stars and generate signals corresponding to the positions of the stars as seen in its field of view. The star catalog contains star location data that is stored using a primary and multiple secondary arrays sorted by both declination (DEC) and right ascension (RA), respectively. The star location data stored in the star catalog is predetermined by calculating a plurality of desired star locations, associating one of a plurality of stars with each of the plurality of desired star locations based upon a neighborhood association angle to generate an associated plurality of star locations: If an artificial star gap occurs during association, then the neighborhood association angle for reassociation is increased. The controller uses the star catalog to determine which stars to select to provide star measurement residuals for correcting gyroscope bias and spacecraft attitude.

  3. jTracker and Monte Carlo Comparison

    Science.gov (United States)

    Selensky, Lauren; SeaQuest/E906 Collaboration

    2015-10-01

    SeaQuest is designed to observe the characteristics and behavior of `sea-quarks' in a proton by reconstructing them from the subatomic particles produced in a collision. The 120 GeV beam from the main injector collides with a fixed target and then passes through a series of detectors which records information about the particles produced in the collision. However, this data becomes meaningful only after it has been processed, stored, analyzed, and interpreted. Several programs are involved in this process. jTracker (sqerp) reads wire or hodoscope hits and reconstructs the tracks of potential dimuon pairs from a run, and Geant4 Monte Carlo simulates dimuon production and background noise from the beam. During track reconstruction, an event must meet the criteria set by the tracker to be considered a viable dimuon pair; this ensures that relevant data is retained. As a check, a comparison between a new version of jTracker and Monte Carlo was made in order to see how accurately jTracker could reconstruct the events created by Monte Carlo. In this presentation, the results of the inquest and their potential effects on the programming will be shown. This work is supported by U.S. DOE MENP Grant DE-FG02-03ER41243.

  4. Developments for the TOF Straw Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Ucar, A.

    2006-07-01

    COSY-TOF is a very large acceptance spectrometer for charged particles using precise information on track geometry and time of flight of reaction products. It is an external detector system at the Cooler Synchrotron and storage ring COSY in Juelich. In order to improve the performance of the COSY-TOF, a new tracking detector ''Straw Tracker'' is being constructed which combines very low mass, operation in vacuum, very good resolution, high sampling density and very high acceptance. A comparison of pp{yields}d{pi}{sup +} data and a simulation using the straw tracker with geometry alone indicates big improvements with the new tracker. In order to investigate the straw tracker properties a small tracking hodoscope ''cosmic ray test facility'' was constructed in advance. It is made of two crossed hodoscopes consisting of 128 straw tubes arranged in 4 double planes. For the first time Juelich straws have been used for 3 dimensional reconstruction of cosmic ray tracks. In this illuminating field the space dependent response of scintillators and a straw tube were studied. (orig.)

  5. The CMS silicon strip tracker modules production

    CERN Document Server

    Giorgi, M

    2006-01-01

    To complete the construction of the CMS silicon strip tracker, about 16,000 silicon microstrip detector modules will be required. In order to guarantee the uniform quality of the produced modules and to be able to match the deadlines requested by the CMS collaboration, a semi-industrialized organization has been developed, and the different components are being presented here.

  6. UK semiconductor tracker parts head for CERN

    CERN Multimedia

    Holland, Colin

    2005-01-01

    The last of the 4 barrels that make up the central part of the Semiconductor Tracker (SCT), the heart of the biggest physics collaboration in the world have left Oxford for its new home at the European Particle Physics Laboratory, CERN, near Geneva

  7. Expected performance of the ATLAS Inner Tracker

    CERN Document Server

    Viel, Simon; The ATLAS collaboration

    2016-01-01

    These slides present the expected tracking performance of the ATLAS Inner Tracker, based on the latest available public results (scoping document). More recent layout designs currently under consideration are also shown. The extended inner pixel barrel concept is discussed in more detail, along with test beam results demonstrating the proof-of-principle.

  8. The D0 Silicon Microstrip Tracker

    CERN Document Server

    Ahmed, S N; Aoki, M; Åsman, B; Austin, S; Bagby, L; Barberis, E; Baringer, P; Bean, A; Bischoff, A; Blekman, F; Bolton, T A; Boswell, C; Bowden, M; Browning, F; Buchholz, D; Burdin, S; Butler, D; Cease, H; Choi, S; Clark, A R; Clutter, J; Cooper, A; Cooper, W E; Corcoran, M; de Jong, S J; Demarteau, M; Demina, R; Desai, S; Derylo, G; Ellison, J; Ermolov, P; Fagan, J; Fast, J; Filthaut, F; Foglesong, J; Fox, H; Galea, C F; Gardner, J; Genik, R J; Gerber, C E; Gershtein, Y; Gounder, K; Grinstein, S; Gu, W; Gutierrez, P; Haggerty, H; Hall, R E; Hagopian, S; Hance, R; Harder, K; Heger, P; Heinson, A P; Heintz, U; Hesketh, G; Hover, D; Howell, J; Hrycyk, M; Iashvili, I; Johnson, M; Jöstlein, H; Juste, A; Kahl, W; Kajfasz, E; Karmanov, D; Kesisoglou, S; Khanov, A; King, J; Kleinfelder, S; Kowalski, J; Krempetz, K; Kubantsev, M; Kulik, Y; Landsberg, G; Leflat, A; Lehner, F; Lipton, R; Mao, H S; Martin, M; Mateski, J; Matulik, M; McKenna, M; Melnitchouk, A; Merkin, M; Mihalcea, D; Milgrome, O; Montgomery, H E; Moua, S; Naumann, N A; Nomerotski, A; Olis, D; O'Neil, D C; Garzón, G J Otero y; Parua, N; Pawlak, J; Petteni, M; Quinn, B; Rapidis, P A; Ratzmann, P; Rizatdinova, F; Roco, M; Rucinski, R; Rykalin, V; Schellman, H; Schmitt, W; Sellberg, G; Serritella, C; Shabalina, E; Sidwell, R A; Simak, V; Smith, E; Squires, B; Stanton, N R; Steinbrück, G; Strandberg, J; Strandberg, S; Strauss, M; Stredde, S; Toukhtarov, A; Tripathi, S M; Trippe, T G; Tsybychev, D; Utes, M; van Gemmeren, P; Vaz, M; Weber, M; Wijngaarden, D A; Wish, J; Womersley, J; Yarema, R; Ye, Z; Zieminski, A; Zimmerman, T; Zverev, E G

    2010-01-01

    This paper describes the mechanical design, the readout chain, the production, testing and the installation of the Silicon Microstrip Tracker of the D0 experiment at the Fermilab Tevatron collider. In addition, description of the performance of the detector during the experiment data collection between 2001 and 2010 is provided.

  9. Developments for the TOF Straw Tracker

    International Nuclear Information System (INIS)

    COSY-TOF is a very large acceptance spectrometer for charged particles using precise information on track geometry and time of flight of reaction products. It is an external detector system at the Cooler Synchrotron and storage ring COSY in Juelich. In order to improve the performance of the COSY-TOF, a new tracking detector ''Straw Tracker'' is being constructed which combines very low mass, operation in vacuum, very good resolution, high sampling density and very high acceptance. A comparison of pp→dπ+ data and a simulation using the straw tracker with geometry alone indicates big improvements with the new tracker. In order to investigate the straw tracker properties a small tracking hodoscope ''cosmic ray test facility'' was constructed in advance. It is made of two crossed hodoscopes consisting of 128 straw tubes arranged in 4 double planes. For the first time Juelich straws have been used for 3 dimensional reconstruction of cosmic ray tracks. In this illuminating field the space dependent response of scintillators and a straw tube were studied. (orig.)

  10. CDF central detector installation. An efficient merge of digital photogrammetry and laser tracker metrology

    International Nuclear Information System (INIS)

    Metrology for Run II at the Collider Detector at Fermilab (CDF) required a very complex geodetic survey. The Collision Hall network, surveyed with a Laser Tracker and digital level, provides a constraining network for the positioning of the Central Detector (CD). A part-based Laser Tracker network, which surrounded the 2,000-ton CD, was used as control for assembly. Subassembly surveys of the Detector's major components were measured as independent networks using Laser Tracker, V-STARS/S (Video-Simultaneous Triangulation And Resection System/Single camera) digital photogrammetry system, and BETS (Brunson Electronic Theodolite System) theodolite triangulation system. Each subassembly survey was transformed into and constrained by the part-based network. For roll-in, the CD part-based network was transformed into the Collision Hall network coordinate system. The CD was positioned in the Collision Hall using two Laser Trackers in 'stakeout mode.' This paper discusses the survey, adjustment, transformation, and precision of the various networks. (author)

  11. Conceptual design report for the Solenoidal Tracker at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    The STAR Collaboration

    1992-06-15

    The Solenoidal Tracker At RHIC (STAR) will search for signatures of quark-gluon plasma (QGP) formation and investigate the behavior of strongly interacting matter at high energy density. The emphasis win be the correlation of many observables on an event-by-event basis. In the absence of definitive signatures for the QGP, it is imperative that such correlations be used to identify special events and possible signatures. This requires a flexible detection system that can simultaneously measure many experimental observables. The physics goals dictate the design of star and it`s experiment. To meet the design criteria, tracking, momentum analysis, and particle identification of most of the charged particles at midrapidity are necessary. The tracking must operate in conditions at higher than the expected maximum charged particle multiplicities for central Au + Au collisions. Particle identification of pions/kaons for p < 0.7 GeV/c and kaons/protons for p < 1 GeV/c, as well as measurement of decay particles and reconstruction of secondary vertices will be possible. A two-track resolution of 2 cm at 2 m radial distance from, the interaction is expected. Momentum resolution of {Delta}p/p {approximately} 0.02 at p = 0.1 GeV/c is required to accomplish the physics, and,{Delta}p/p of several percent at p = 10 GeV/c is sufficient to accurately measure the rapidly failing spectra at high Pt and particles from mini-jets and jets.

  12. Conceptual design report for the Solenoidal Tracker at RHIC

    International Nuclear Information System (INIS)

    The Solenoidal Tracker At RHIC (STAR) will search for signatures of quark-gluon plasma (QGP) formation and investigate the behavior of strongly interacting matter at high energy density. The emphasis win be the correlation of many observables on an event-by-event basis. In the absence of definitive signatures for the QGP, it is imperative that such correlations be used to identify special events and possible signatures. This requires a flexible detection system that can simultaneously measure many experimental observables. The physics goals dictate the design of star and it's experiment. To meet the design criteria, tracking, momentum analysis, and particle identification of most of the charged particles at midrapidity are necessary. The tracking must operate in conditions at higher than the expected maximum charged particle multiplicities for central Au + Au collisions. Particle identification of pions/kaons for p < 0.7 GeV/c and kaons/protons for p < 1 GeV/c, as well as measurement of decay particles and reconstruction of secondary vertices will be possible. A two-track resolution of 2 cm at 2 m radial distance from, the interaction is expected. Momentum resolution of Δp/p ∼ 0.02 at p = 0.1 GeV/c is required to accomplish the physics, and,Δp/p of several percent at p = 10 GeV/c is sufficient to accurately measure the rapidly failing spectra at high Pt and particles from mini-jets and jets

  13. The research and development of the automatic solar power tracker

    Directory of Open Access Journals (Sweden)

    Li Yan Ping

    2016-01-01

    Full Text Available The article describes a kind of automatic tracker using solar power. It depends on two important parts which are servo system and adjusting mechanism system to keep the tracker operating normally. The article focuses on describing the characteristics and functions of two systems and the operating details of the automatic solar power tracker.

  14. Evaluation of a remote webcam-based eye tracker

    DEFF Research Database (Denmark)

    Skovsgaard, Henrik; Agustin, Javier San; Johansen, Sune Alstrup;

    2011-01-01

    In this paper we assess the performance of an open-source gaze tracker in a remote (i.e. table-mounted) setup, and compare it with two other commercial eye trackers. An experiment with 5 subjects showed the open-source eye tracker to have a significantly higher level of accuracy than one of the c...

  15. Alignment procedures for the CMS silicon tracker

    CERN Document Server

    Behr, Joerg

    2012-01-01

    The CMS all-silicon tracker consists of 16588 modules. Therefore its alignment procedures require sophisticated algorithms. Advanced tools of computing, tracking and data analysis have been deployed for reaching the targeted performance. Ultimate local precision is now achieved by the determination of sensor curvatures, challenging the algorithms to determine about 200k parameters simultaneously. Systematic biases in the geometry are controlled by adding further information into the alignment workflow, e.g. the mass of decaying resonances. The orientation of the tracker with respect to the magnetic field of CMS is determined with a stand-alone chi-square minimization procedure. The geometries are finally carefully validated. The monitored quantities include the basic track quantities for tracks from both collisions and cosmic muons and physics observables.

  16. Alignment strategy for the CMS Tracker

    CERN Document Server

    Weber, M

    2008-01-01

    The CMS Tracker measures the momentum of charged particles created in proton-proton interactions with 14\\,TeV nominal center-of-mass energy close to the interaction region. Its excellent single-point position resolution of 9--60\\,$\\mu$m\\ is far below typical construction tolerances, and together with its high granularity renders the alignment a demanding task, which needs to aim at micro-meter level precision. A strategy to align the CMS tracker with its 15\\,148 silicon strip and 1\\,440 silicon pixel modules, starting from survey measurements during construction, incorporating information from the laser hardware monitoring system and finally using collision and non-collision tracks for highest precision has been developed and is detailed in this article.

  17. OFFSET: Optical Fiber Folded Scintillating Extended Tracker

    International Nuclear Information System (INIS)

    The OFFSET collaboration aims at the development of a novel system for tracking charged particles, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. This paper presents the first prototype of this tracker, having a 20×20 cm2 sensitive area made by two crossed ribbons of 500μm square scintillating fibers. The track position information is extracted in real time using a reduced number of read-out channels to obtain very large detection area at moderate cost and complexity. The performance of the tracker was investigated using β sources, cosmic rays and a 62 MeV proton beam

  18. The Alpha Magnetic Spectrometer Silicon Tracker

    International Nuclear Information System (INIS)

    The Alpha Magnetic Spectrometer (AMS) is designed as a independent module for installation on the International Space Station Alpha (ISSA) in the year 2002 for an operational period of three years. The principal scientific objectives are the searches for antimatter and dark matter in cosmic rays. The AMS uses 5.5 m2 of silicon microstrip sensors to reconstruct charged particle trajectories in the field of a permanent magnet. The detector design and construction covered a 3 yr period which terminated with a test flight on the NASA space shuttle Discovery during June 2-12, 1988. In this contribution, we describe the shuttle version of the AMS silicon tracker, including preliminary results of the tracker performance during the flight. (author)

  19. Target for optically activated seekers and trackers

    Science.gov (United States)

    Lakin, C. T.; Willett, N. F.

    1984-05-01

    This abstract discloses a target for optically activated seekers and trackers (TOAST) which provides for calibrated and variable target characteristics such as size, intensity, spatial position, color and interfering background. The TOAST has a first ilumination system providing a target light beam through an adjustable iris which controls image size. The target beam passes through a collimator lens which focuses the light at infinity. With the target beam focused at infinity, the motion of an elevation plate lengthens or shortens the distance from the collimator lens to a one motion mirror. The target beam is attenuated by a variable filter driven by a servo-motor, and a color selection process is provided by passing the beam through spectral filters. A background light beam with background imagery is provided to the beamsplitter mirror and mixed with the target image so as to simulate the target environment encountered by an operating optically activated seeker and tracker.

  20. Alignment procedures for the CMS silicon tracker

    International Nuclear Information System (INIS)

    The CMS all-silicon tracker consists of 16588 modules. Therefore its alignment procedures require sophisticated algorithms. Advanced tools of computing, tracking and data analysis have been deployed for reaching the targeted performance. Ultimate local precision is now achieved by the determination of sensor curvatures, challenging the algorithms to determine about 200k parameters simultaneously. Systematic biases in the geometry are controlled by adding further information into the alignment workflow, e.g. the mass of decaying resonances. The orientation of the tracker with respect to the magnetic field of CMS is determined with a stand-alone chi-square minimization procedure. The geometries are finally carefully validated. The monitored quantities include the basic track quantities for tracks from both collisions and cosmic muons and physics observables.

  1. CMS tracker towards the HL-LHC

    CERN Document Server

    Alunni Solestizi, Luisa

    2015-01-01

    In sight of the incoming new LHC era (High Luminosity - LHC), characterized by a jump forward in the precision boundary and in the event rate, all the CMS sub-detector are developing and studying innovative strategies of trigger, pattern recognition, event timing and so on. A crucial aspect will be the online event selection: a totally new paradigm is needed, given the huge amount of events. In this picture the most granular and innermost sub-detector, the tracker, will play a decisive role. The phase-2 tracker will be involved in the L1 Trigger and, taking advantage of both the Associative Memories and the FPGA, it can ensure a trigger decision in proper time and with satisfactory performances.

  2. Magnet Test Setup of the CMS Tracker ready for installation

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    The pieces of the Tracker that will be operated in the forthcoming Magnet Test and Cosmic Challenge (MTCC) have been transported inside the dummy tracker support tube to the CMS experimental hall (Point 5, Cessy). The operation took place during the night of 12th May, covering the ~15km distance in about three hours. The transport was monitored for shocks, temperature and humidity with the help of the CERN TS-IC section. The Tracker setup comprises segments of the Tracker Inner Barrel (TIB), the Tracker Outer Barrel (TOB) and Tracker EndCaps (TEC) detectors. It represents roughly 1% of the final CMS Tracker. Installation into the solenoid is foreseen to take place on Wednesday 17th May.

  3. Search for Tracker Potentials in Quintessence Theory

    OpenAIRE

    Johri, Vinod B.

    2001-01-01

    We report a significant finding in Quintessence theory that the the scalar fields with tracker potentials have a model-independent scaling behaviour in the expanding universe. So far widely discussed exponential,power law or hyperbolic potentials can simply mimic the tracking behaviour over a limited range of redshift. In the small redshift range where the variation of the tracking parameter $\\epsilon$ may be taken to be negligible, the differential equation of generic potentials leads to hyp...

  4. Mobile application CarbonTracker development

    OpenAIRE

    Adžič, Nik

    2012-01-01

    The following Bachelor's thesis discusses the CarbonTracker mobile application development as well as the part of its server which may run without connection to the mobile application and may be used independently of it. The mobile application was developed in the Java programming language for the currently leading operating system for mobile applications-Android. It was designed in the integrated development environment (IDE) Eclipse with the Android Software Development Kit (SDK) and the...

  5. Dynamic exit pupil trackers for autostereoscopic displays

    OpenAIRE

    Akşit, Kaan; Ölçer, Selim; Ürey, Hakan; Baghsiahi, Hadi; Surman, Phil; Willman, Eero; Selviah, David R.; Day, Sally

    2013-01-01

    Dynamic exit pupil trackers for autostereoscopic displays Kaan Akşit,1,* Hadi Baghsiahi,2 Phil Surman,3 Selim Ӧlçer,1 Eero Willman,2 David R. Selviah,2 Sally Day, 2 and Hakan Urey1 1Koç University, Department of Electrical Engineering Istanbul, 34450, Turkey 2University College London, UCL, Department of Electronic & Electrical Engineering, WC1E 7JE, London, UK 3De Montfort University, Department of Computer Technology, Leicester, UK * Abstract: This...

  6. Radiation monitoring system for LHCb inner tracker

    International Nuclear Information System (INIS)

    Performance requirements to and the design of a radiation monitoring system (RMS) for the LHCb inner Tracker (CERN) have been presented. The physical principle of operation and some constructional details of metal foil detectors (MFDs) developed at the Institute for Nuclear Research of the National Academy of Sciences of Ukraine and used in the RMS manufacture have been described. The results of testing demonstrate that the parameters of the RMS correspond to the requirements of the LHCb experiment

  7. Robust visual tracking with dual spatio-temporal context trackers

    Science.gov (United States)

    Sun, Shiyan; Zhang, Hong; Yuan, Ding

    2015-12-01

    Visual tracking is a challenging problem in computer vision. Recent years, significant numbers of trackers have been proposed. Among these trackers, tracking with dense spatio-temporal context has been proved to be an efficient and accurate method. Other than trackers with online trained classifier that struggle to meet the requirement of real-time tracking task, a tracker with spatio-temporal context can run at hundreds of frames per second with Fast Fourier Transform (FFT). Nevertheless, the performance of the tracker with Spatio-temporal context relies heavily on the learning rate of the context, which restricts the robustness of the tracker. In this paper, we proposed a tracking method with dual spatio-temporal context trackers that hold different learning rate during tracking. The tracker with high learning rate could track the target smoothly when the appearance of target changes, while the tracker with low learning rate could percepts the occlusion occurring and continues to track when the target starts to emerge again. To find the target among the candidates from these two trackers, we adopt Normalized Correlation Coefficient (NCC) to evaluate the confidence of each sample. Experimental results show that the proposed algorithm performs robustly against several state-of-the-art tracking methods.

  8. Conceptual design report for the Solenoidal Tracker at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    1992-06-15

    The Solenoidal Tracker At RHIC (STAR) will search for signatures of quark-gluon plasma (QGP) formation and investigate the behavior of strongly interacting matter at high energy density. The emphasis win be the correlation of many observables on an event-by-event basis. In the absence of definitive signatures for the QGP, it is imperative that such correlations be used to identify special events and possible signatures. This requires a flexible detection system that can simultaneously measure many experimental observables. The physics goals dictate the design of star and it's experiment. To meet the design criteria, tracking, momentum analysis, and particle identification of most of the charged particles at midrapidity are necessary. The tracking must operate in conditions at higher than the expected maximum charged particle multiplicities for central Au + Au collisions. Particle identification of pions/kaons for p < 0.7 GeV/c and kaons/protons for p < 1 GeV/c, as well as measurement of decay particles and reconstruction of secondary vertices will be possible. A two-track resolution of 2 cm at 2 m radial distance from, the interaction is expected. Momentum resolution of {Delta}p/p {approximately} 0.02 at p = 0.1 GeV/c is required to accomplish the physics, and,{Delta}p/p of several percent at p = 10 GeV/c is sufficient to accurately measure the rapidly failing spectra at high Pt and particles from mini-jets and jets.

  9. Dynamic exit pupil trackers for autostereoscopic displays.

    Science.gov (United States)

    Akşit, Kaan; Baghsiahi, Hadi; Surman, Phil; Ölçer, Selim; Willman, Eero; Selviah, David R; Day, Sally; Urey, Hakan

    2013-06-17

    This paper describes the first demonstrations of two dynamic exit pupil (DEP) tracker techniques for autostereoscopic displays. The first DEP tracker forms an exit pupil pair for a single viewer in a defined space with low intraocular crosstalk using a pair of moving shutter glasses located within the optical system. A display prototype using the first DEP tracker is constructed from a pair of laser projectors, pupil-forming optics, moving shutter glasses at an intermediate pupil plane, an image relay lens, and a Gabor superlens based viewing screen. The left and right eye images are presented time-sequentially to a single viewer and seen as a 3D image without wearing glasses and allows the viewer to move within a region of 40 cm × 20 cm in the lateral plane, and 30 cm along the axial axis. The second DEP optics can move the exit pupil location dynamically in a much larger 3D space by using a custom spatial light modulator (SLM) forming an array of shutters. Simultaneous control of multiple exit pupils in both lateral and axial axes is demonstrated for the first time and provides a viewing volume with an axial extent of 0.6-3 m from the screen and within a lateral viewing angle of ± 20° for multiple viewers. This system has acceptable crosstalk (< 5%) between the stereo image pairs. In this novel version of the display the optical system is used as an advanced dynamic backlight for a liquid crystal display (LCD). This has advantages in terms of overall display size as there is no requirement for an intermediate image, and in image quality. This system has acceptable crosstalk (< 5%) between the stereo image pairs. PMID:23787621

  10. Autonomous Spacecraft Navigation With Pulsars

    CERN Document Server

    Becker, Werner; Jessner, Axel

    2013-01-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  11. The superB silicon vertex tracker

    International Nuclear Information System (INIS)

    The SuperB asymmetric e+-e- collider has been designed to deliver a luminosity greater than 1036cm-2s-1 with moderate beam currents. Comparing to current B-Factories, the reduced center of mass boost of the SuperB machine requires improved vertex resolution to allow precision measurements sensitive to New Physics. We present the conceptual design of the silicon vertex tracker (SVT) for the SuperB detector with the present status of the R and D on the different options under study for its innermost Layer0.

  12. The silicon microstrip tracker for CMS

    International Nuclear Information System (INIS)

    The CMS silicon strip tracker involves about 70 m2 of instrumented silicon, with approximately 18500 microstrip detectors read out by 5 x 106 electronics channels. It has to satisfy a set of stringent requirements imposed by the environment and by the physics expected at the LHC: low cell occupancy and good resolution, radiation hardness aided by adequate cooling, low mass combined with high stability. These conditions have been incorporated in a highly modular design of the detector modules and their support structures, chosen to facilitate construction and to allow for easy assembly and maintenance

  13. Readout electronics for the ATLAS semiconductor tracker

    International Nuclear Information System (INIS)

    The binary readout architecture as a base-line and the analogue one as a fall-forward option have been adopted recently by the ATLAS semiconductor tracker group for the readout of silicon strip detectors. A brief overview of different architectures considered before as well as the status of the binary readout development will be presented. A new idea of the binary readout architecture employing a dual threshold scheme will be discussed and new results obtained for the full analogue readout chip realised in the DMILL technology will be reported. (orig.)

  14. LHCb: The LHCb Silicon Tracker: Running experience

    CERN Multimedia

    Saornil Gamarra, S

    2012-01-01

    The LHCb Silicon Tracker is part of the main tracking system of the LHCb detector at the LHC. It measures very precisely the particle trajectories coming from the interaction point in the region of high occupancies around the beam axis. After presenting our production and comissioning issues in TWEPP 2008, we report on our running experience. Focusing on electronic and hardware issues as well as operation and maintenance adversities, we describe the lessons learned and the pitfalls encountered after three years of successful operation.

  15. Trigeminal autonomic cephalgias

    OpenAIRE

    Benoliel, Rafael

    2012-01-01

    1. Trigeminal autonomic cephalgias (TACs) are headaches/facial pains classified together based on:a suspected common pathophysiology involving the trigeminovascular system, the trigeminoparasympathetic reflex and centres controlling circadian rhythms;a similar clinical presentation of trigeminal pain, and autonomic activation.

  16. Testing for autonomic neuropathy

    DEFF Research Database (Denmark)

    Hilsted, J

    1984-01-01

    disease, and may be nonspecific. A number of recently developed quantifiable and reproducible autonomic nerve function tests are reviewed, with emphasis on the physiological basis of the tests and on practical applicability. Finally, diagnostic criteria, based on autonomic nerve function tests, are...

  17. Performance studies of the CMS strip tracker before installation

    OpenAIRE

    Adam, W.; Anttila, E.; Czellar, S.; Engström, P.; HÀrkönen, J.; KarimÀki, V.; Kortesmaa, J; Kuronen, A.; Lampén, T.; Lindén, T.; Luukka, P. -R.; MÀenpÀÀ, T.; Michal, S.; Tuominen, E.; Tuominiemi, J.

    2009-01-01

    In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to understand the efficiency and alignment of the strip tracker modules, a cosmic ray trigger was implemented. From March through July 4.5 million tr...

  18. WalkNRide: contextualising feedback in physical activity trackers

    OpenAIRE

    Barros, Sérgio Manuel Nóbrega de

    2014-01-01

    Increasing levels of sedentarism and obesity, along with advances in sensor technologies have instigated a market for wearable activity trackers, electronic devices that sense users’ physical activity levels with the goals of self-monitoring and behaviour change. Nowadays, activity trackers are one of the most desirable technologies, making up for a market of over $230 million in 2013. However, despite the spike of users’ interest, activity trackers have been shown to lose their appeal over t...

  19. Modelling Structural Flexure Effects in CPV Sun Trackers

    OpenAIRE

    LUQUE-HEREDIA, Ignacio; Quéméré, G.; Magalhães, P.H.; Fraile de Lerma, Alberto; Hermanns, Lutz Karl Heinz; Alarcón Álvarez, Enrique; Luque López, Antonio

    2006-01-01

    Nowadays CPV trends mostly based in lens parqueted flat modules, enable the separate design of the sun tracker. To enable this possibility a set of specifications is to be prescribed for the tracker design team, which take into account fundamental requisites such as the maximum service loads both permanent and variable, the sun tracking accuracy and the tracker structural stiffness required to maintain the CPV array acceptance angle loss below a certain threshold. In its first part this paper...

  20. Success potential of automated star pattern recognition

    Science.gov (United States)

    Van Bezooijen, R. W. H.

    1986-01-01

    A quasi-analytical model is presented for calculating the success probability of automated star pattern recognition systems for attitude control of spacecraft. The star data is gathered by an imaging star tracker (STR) with a circular FOV capable of detecting 20 stars. The success potential is evaluated in terms of the equivalent diameters of the FOV and the target star area ('uniqueness area'). Recognition is carried out as a function of the position and brightness of selected stars in an area around each guide star. The success of the system is dependent on the resultant pointing error, and is calculated by generating a probability distribution of reaching a threshold probability of an unacceptable pointing error. The method yields data which are equivalent to data available with Monte Carlo simulatins. When applied to the recognition system intended for use on the Space IR Telescope Facility it is shown that acceptable pointing, to a level of nearly 100 percent certainty, can be obtained using a single star tracker and about 4000 guide stars.

  1. Lunar Navigator - A Miniature, Fully Autonomous, Lunar Navigation, Surveyor, and Range Finder System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcosm proposes to design and develop a fully autonomous Lunar Navigator based on our MicroMak miniature star sensor and a gravity gradiometer similar to one on...

  2. The ATLAS Semiconductor tracker: operations and performance

    CERN Document Server

    Pani, P; The ATLAS collaboration

    2013-01-01

    Tracker After more than 3 years of successful operation at the LHC, we report on the operation and performance of the Semi-Conductor Tracker (SCT) functioning in a high luminosity, high radiation environment. The SCT is part of the ATLAS experiment at CERN and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibers. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications; the alignment is very cl...

  3. The LHCb Upgrade Scintillating Fibre Tracker

    CERN Document Server

    Leverington, Blake D

    2014-01-01

    The Scintillating Fibre (SciFi) Tracker is designed to replace the current downstream tracking detectors in the LHCb Upgrade during 2018 (CERN/LHCC 2014-001; LHCb TDR 15). The operation and the results obtained from the data collected 2011 and 2012 demonstrate that the current detector is robust and functioning very well. However, the limit of O ( 1 fb-1) of data per year cannot be overcome without improving the detector. This will be achieved using 25 ns bunch spacing with the average number of proton-proton interactions per bunch crossing n = 7 : 6. Collecting data at this luminosity will only be possible if the detector is improved by increasing the readout of the front-end electronics to 40MHz and implementing a more flexible software-based triggering system that will increase the data rate as well as the efficiency. The increase in interactions per bunch crossing will result in an increased occupancy in the tracking detectors and will exceed the operational occupancy for the Outer Tracker. Here we presen...

  4. The alignment of the CMS Silicon Tracker

    International Nuclear Information System (INIS)

    The complex system of the CMS all-silicon Tracker, with 15 148 silicon strip and 1440 silicon pixel modules, requires sophisticated alignment procedures. In order to achieve an optimal track-parameter resolution, the position and orientation of its modules need to be determined with a precision of few micrometers. We present results of the alignment of the full Tracker, in its final position, used for the reconstruction of the first collisions recorded by the CMS experiment. The aligned geometry is based on the analysis of several million reconstructed tracks recorded during the commissioning of the CMS experiment, both with cosmic rays and with the first proton-proton collisions. The geometry has been systematically monitored in the different periods of operation of the CMS detector. The results have been validated by several data-driven studies (laser beam cross-checks, track fit self-consistency, track residuals in overlapping module regions, and track parameter resolution) and compared with predictions obtained from a detailed detector simulation. (author)

  5. Monitoring the CMS strip tracker readout system

    International Nuclear Information System (INIS)

    The CMS Silicon Strip Tracker at the LHC comprises a sensitive area of approximately 200 m2 and 10 million readout channels. Its data acquisition system is based around a custom analogue front-end chip. Both the control and the readout of the front-end electronics are performed by off-detector VME boards in the counting room, which digitise the raw event data and perform zero-suppression and formatting. The data acquisition system uses the CMS online software framework to configure, control and monitor the hardware components and steer the data acquisition. The first data analysis is performed online within the official CMS reconstruction framework, which provides many services, such as distributed analysis, access to geometry and conditions data, and a Data Quality Monitoring tool based on the online physics reconstruction. The data acquisition monitoring of the Strip Tracker uses both the data acquisition and the reconstruction software frameworks in order to provide real-time feedback to shifters on the operational state of the detector, archiving for later analysis and possibly trigger automatic recovery actions in case of errors. Here we review the proposed architecture of the monitoring system and we describe its software components, which are already in place, the various monitoring streams available, and our experiences of operating and monitoring a large-scale system

  6. Overview of the ATLAS Fast Tracker Project

    CERN Document Server

    Ancu, Lucian Stefan; The ATLAS collaboration

    2016-01-01

    The next LHC runs, with a significant increase in instantaneous luminosity, will provide a big challenge for the trigger and data acquisition systems of all the experiments. An intensive use of the tracking information at the trigger level will be important to keep high efficiency for interesting events despite the increase in multiple collisions per bunch crossing. In order to increase the use of tracks within the High Level Trigger, the ATLAS experiment planned the installation of a hardware processor dedicated to tracking: the Fast TracKer processor. The Fast Tracker is designed to perform full scan track reconstruction of every event accepted by the ATLAS first level hardware trigger. To achieve this goal the system uses a parallel architecture, with algorithms designed to exploit the computing power of custom Associative Memory chips, and modern field programmable gate arrays. The processor will provide computing power to reconstruct tracks with transverse momentum greater than 1 GeV in the whol...

  7. The ATLAS fast tracker processor design

    CERN Document Server

    Volpi, Guido; Albicocco, Pietro; Alison, John; Ancu, Lucian Stefan; Anderson, James; Andari, Nansi; Andreani, Alessandro; Andreazza, Attilio; Annovi, Alberto; Antonelli, Mario; Asbah, Needa; Atkinson, Markus; Baines, J; Barberio, Elisabetta; Beccherle, Roberto; Beretta, Matteo; Biesuz, Nicolo Vladi; Blair, R E; Bogdan, Mircea; Boveia, Antonio; Britzger, Daniel; Bryant, Partick; Burghgrave, Blake; Calderini, Giovanni; Camplani, Alessandra; Cavaliere, Viviana; Cavasinni, Vincenzo; Chakraborty, Dhiman; Chang, Philip; Cheng, Yangyang; Citraro, Saverio; Citterio, Mauro; Crescioli, Francesco; Dawe, Noel; Dell'Orso, Mauro; Donati, Simone; Dondero, Paolo; Drake, G; Gadomski, Szymon; Gatta, Mauro; Gentsos, Christos; Giannetti, Paola; Gkaitatzis, Stamatios; Gramling, Johanna; Howarth, James William; Iizawa, Tomoya; Ilic, Nikolina; Jiang, Zihao; Kaji, Toshiaki; Kasten, Michael; Kawaguchi, Yoshimasa; Kim, Young Kee; Kimura, Naoki; Klimkovich, Tatsiana; Kolb, Mathis; Kordas, K; Krizka, Karol; Kubota, T; Lanza, Agostino; Li, Ho Ling; Liberali, Valentino; Lisovyi, Mykhailo; Liu, Lulu; Love, Jeremy; Luciano, Pierluigi; Luongo, Carmela; Magalotti, Daniel; Maznas, Ioannis; Meroni, Chiara; Mitani, Takashi; Nasimi, Hikmat; Negri, Andrea; Neroutsos, Panos; Neubauer, Mark; Nikolaidis, Spiridon; Okumura, Y; Pandini, Carlo; Petridou, Chariclia; Piendibene, Marco; Proudfoot, James; Rados, Petar Kevin; Roda, Chiara; Rossi, Enrico; Sakurai, Yuki; Sampsonidis, Dimitrios; Saxon, James; Schmitt, Stefan; Schoening, Andre; Shochet, Mel; Shoijaii, Jafar; Soltveit, Hans Kristian; Sotiropoulou, Calliope-Louisa; Stabile, Alberto; Swiatlowski, Maximilian J; Tang, Fukun; Taylor, Pierre Thor Elliot; Testa, Marianna; Tompkins, Lauren; Vercesi, V; Wang, Rui; Watari, Ryutaro; Zhang, Jianhong; Zeng, Jian Cong; Zou, Rui; Bertolucci, Federico

    2015-01-01

    The extended use of tracking information at the trigger level in the LHC is crucial for the trigger and data acquisition (TDAQ) system to fulfill its task. Precise and fast tracking is important to identify specific decay products of the Higgs boson or new phenomena, as well as to distinguish the contributions coming from the many collisions that occur at every bunch crossing. However, track reconstruction is among the most demanding tasks performed by the TDAQ computing farm; in fact, complete reconstruction at full Level-1 trigger accept rate (100 kHz) is not possible. In order to overcome this limitation, the ATLAS experiment is planning the installation of a dedicated processor, the Fast Tracker (FTK), which is aimed at achieving this goal. The FTK is a pipeline of high performance electronics, based on custom and commercial devices, which is expected to reconstruct, with high resolution, the trajectories of charged-particle tracks with a transverse momentum above 1 GeV, using the ATLAS inner tracker info...

  8. The Alignment of the CMS Silicon Tracker

    International Nuclear Information System (INIS)

    The complex system of the CMS all-silicon Tracker, with 15148 silicon strips and 1440 silicon pixel modules, requires sophisticated alignment procedures. In order to achieve an optimal track-parameter resolution, the position and orientation of its modules need to be determined with a precision of few micrometers. We present results of the alignment of the full Tracker, in its final position, used for the reconstruction of the first collisions recorded by the CMS experiment. The aligned geometry is based on the analysis of several million reconstructed tracks recorded during the commissioning of the CMS experiment, both with cosmic rays and with the first proton-proton collisions. The geometry has been systematically monitored in the different periods of operation of the CMS detector. The results have been validated by several data-driven studies (laser beam cross-checks, track fit self-consistency, track residuals in overlapping module regions, and track parameter resolution) and compared with predictions obtained from a detailed detector simulation.

  9. The CMS tracker alignment in pp collisions

    International Nuclear Information System (INIS)

    The CMS all-silicon tracker consists of 16,588 modules. Aligning these with the desired precision of a few micrometers is only feasible using track based alignment procedures. Ultimate local precision is now achieved by the determination of sensor curvatures. This faces the algorithms with about 200,000 parameters to be calculated simultaneously. The Millipede II program interfaced with CMS software is optimized to provide solution in one step. The main remaining challenges are systematic distortions in the achieved geometry that are systematically biasing the track parameters like the track momenta. These distortions are controlled by adding further information into the alignment workflow, e.g. the mass of decaying resonances. In addition, the orientation of the tracker with respect to the magnetic field of CMS is determined with a stand-alone chi-square minimization procedure. The geometries are finally carefully validated. The monitored quantities include the basic track quantities for tracks from both collisions and cosmic muons and physics observables like resonance masses

  10. Semiconductor Strip Tracker Endcaps come to CERN

    CERN Multimedia

    P. Bell

    The first few months of 2006 saw the delivery to CERN of the final components of the ATLAS Semi-Conductor Tracker (SCT), namely the completed SCT end-caps. Regular ATLAS eNews readers will recall that the SCT barrel arrived in sections in 2005 and was assembled later that year (see the April 2005 and December 2005 issues, respectively.) And as reported in this issue of the eNews, the barrel SCT has recently been integrated with the barrel Transition Radiation Tracker. The end-caps were constructed in Liverpool (side C) and NIKHEF (side A), using components manufactured at many different sites across the world. End-cap C left Liverpool on Monday 20 February and arrived at CERN after a two-day journey by road and through the Channel Tunnel. Accelerations in all three dimensions were monitored during the trip, as was temperature and humidity inside the container; all values remained within pre-specified safe ranges. The end-cap was visually inspected upon arrival, with no obvious damage being seen. Subsequent ...

  11. Autonomous linear lossless systems

    OpenAIRE

    Rao, Shodhan; Rapisarda, Paolo

    2008-01-01

    We define a lossless autonomous system as one having a quadratic differential form associated with it called an energy function, which is positive and which is conserved. We define an oscillatory system as one which has all its trajectories bounded on the entire time axis. In this paper, we show that an autonomous system is lossless if and only if it is oscillatory. Next we discuss a few properties of energy functions of autonomous lossless systems and a suitable way of splitting a given ener...

  12. Autonomous surveillance for biosecurity.

    Science.gov (United States)

    Jurdak, Raja; Elfes, Alberto; Kusy, Branislav; Tews, Ashley; Hu, Wen; Hernandez, Emili; Kottege, Navinda; Sikka, Pavan

    2015-04-01

    The global movement of people and goods has increased the risk of biosecurity threats and their potential to incur large economic, social, and environmental costs. Conventional manual biosecurity surveillance methods are limited by their scalability in space and time. This article focuses on autonomous surveillance systems, comprising sensor networks, robots, and intelligent algorithms, and their applicability to biosecurity threats. We discuss the spatial and temporal attributes of autonomous surveillance technologies and map them to three broad categories of biosecurity threat: (i) vector-borne diseases; (ii) plant pests; and (iii) aquatic pests. Our discussion reveals a broad range of opportunities to serve biosecurity needs through autonomous surveillance. PMID:25744760

  13. An advanced tracker design for pointing and control of space vehicles using the charge injection device

    Science.gov (United States)

    Jones, C.; Kollodge, J. C.

    1982-01-01

    The use of charge transfer devices (CTD) in pointing and control of space vehicles is examined, with emphasis on the use of charge injection devices (CID). The selection of CTD type and CID operation, including CID signal and noise analysis and signal improvement, are discussed. Star tracking operational advantages of the CTD are pointed out, and the tracking optical concept is discussed and graphically depicted. The position interpolation procedure and the effects of rate of stellar motion on position interpolation are considered, and error analysis is examined. Finally, the breadboard and test program are discussed in detail, coarse and fine acquisition, test for star, track pattern, test procedure and results. An overall accuracy performance of approximately 0.02 pixels or approximately 0.8 arcsec for the test equipment and tracker was obtained.

  14. Optimization of the silicon sensors for the CMS tracker

    Science.gov (United States)

    Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Biino, C.; Bilei, G. M.; Bisello, D.; Boemi, D.; Bosi, F.; Borello, L.; Braibant, S.; Breuker, H.; Brunetti, M. T.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Costa, M.; Creanza, D.; D'Alessandro, R.; DeMaria, N.; de Palma, M.; Dell'Orso, R.; Dutta, S.; Favro, G.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A.; Friedl, M.; Fürtjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, W.; Gu, W. H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honkanen, A.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Mättig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Mc Evoy, B.; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Neviani, A.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pernicka, M.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Rizzo, F.; Santocchia, A.; Segneri, G.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuominiemi, J.; Tuuva, T.; Verdini, P. G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B.

    2001-07-01

    The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R&D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker.

  15. Optimization of the silicon sensors for the CMS tracker

    International Nuclear Information System (INIS)

    The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R and D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker

  16. Optimization of the silicon sensors for the CMS tracker

    Energy Technology Data Exchange (ETDEWEB)

    Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Biino, C.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bosi, F.; Borello, L.; Braibant, S.; Breuker, H.; Brunetti, M.T.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Costa, M.; Creanza, D.; D' Alessandro, R.; DeMaria, N.; Palma, M. de; Dell' Orso, R.; Dutta, S.; Favro, G.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Frey, A. E-mail: ariane.frey@cern.ch; Friedl, M.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, W.; Gu, W.H.; Hall, G.; Hammarstrom, R.; Hebbeker, T.; Honkanen, A.; Honma, A.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Mc Evoy, B.; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Neviani, A.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pernicka, M.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Rizzo, F.; Santocchia, A.; Segneri, G.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Starodumov, A.; Stavitski, I.; Surrow, B.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuominiemi, J.; Tuuva, T.; Verdini, P.G.; Viertel, G.; Xie, Z.; Yahong, Li; Watts, S.; Wittmer, B

    2001-07-01

    The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R and D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker.

  17. Study of prototype sensors for the Upstream Tracker Upgrade

    CERN Document Server

    Abba, Andrea; Blusk, Steven R.; Bursche, Albert; Davis, Adam; Dendek, Adam Mateusz; Dey, Biplab; Ely, Scott Edward; Forshaw, Dean Charles; Fu, Jinlin; Kelsey, Matthew Jordan; Lionetto, Federica; Manning Jr, Peter Michael; Mountain, Ray; Neri, Nicola; Papula, Alana Leigh; Petruzzo, Marco; Pikies, Malgorzata Maria; Rudolph, Matthew Scott; Sokoloff, Michael David; Stone, Sheldon; Szumlak, Tomasz; Wang, Jianchun

    2016-01-01

    Three testbeams were carried out in 2015 to test the performance of prototype sensors for the Upstream Tracker. Two of the testbeams were devoted to studying full size n-in-p sensors, and one was devoted to testing mini-sensors, all from Hamamatsu. Results on the performance of these Upstream Tracker sensor prototypes are presented.

  18. Reliability and validity of ten consumer activity trackers

    NARCIS (Netherlands)

    Kooiman, Thea J.M.; Dontje, Manon L.; Sprenger, Siska R.; Krijnen, Wim P.; Schans, Cees P. van der; Groot, Martijn de

    2015-01-01

    Background: Activity trackers can potentially stimulate users to increase their physical activity behavior. The aim of this study was to examine the reliability and validity of ten consumer activity trackers for measuring step count in both laboratory and free-living conditions. Method: Healthy adul

  19. AUTONOMOUS DRIVEN CAR

    OpenAIRE

    Meeshika Arora

    2013-01-01

    In order to achieve autonomous operation of a vehiclein urban situations with unpredictable traffic, several real timesystems must interoperate, including environment perceptionplanning and control. In addition a robust vehicle platform withappropriate sensors, computational hardware, networking andsoftware infrastructure is essential.

  20. Highly Autonomous Systems Workshop

    Science.gov (United States)

    Doyle, R.; Rasmussen, R.; Man, G.; Patel, K.

    1998-01-01

    It is our aim by launching a series of workshops on the topic of highly autonomous systems to reach out to the larger community interested in technology development for remotely deployed systems, particularly those for exploration.

  1. LHC survey laser tracker controls renovation

    International Nuclear Information System (INIS)

    The LHC survey laser tracker control system is based on an industrial software package (Axyz) from Leica Geosystems (TM) that has an interface to Visual Basic (TM), which we used to automate the geometric measurements for the LHC magnets. With the new version of the Leica software, this Visual Basic (TM) interface is no longer available and we had to redesign the interface software to adapt to a PC-DMIS server that replaced the Axyz software. As this package is no longer supported, we have taken the decision to re-code the automation application in LabVIEW. This presentation describes the existing equipment, interface and application showing the reasons for our decisions to move to PC-DMIS and LabVIEW. A comparison between the new and the existing system is made. (authors)

  2. LHC Survey Laser Tracker Controls Renovation

    CERN Document Server

    Charrondière, C

    2011-01-01

    The LHC survey laser tracker control system is based on an industrial software package (Axyz) from Leica Geosystems™ that has an interface to Visual Basic™, which we used to automate the geometric measurements for the LHC magnets. With the new version of the Leica software, this Visual Basic™ interface is no longerb available and we had to redesign the interface software to adapt to a PC-DMIS server that replaced the Axyz software. As this package is no longer supported, we have taken the decision to recode the automation application in LabVIEW. This presentation describes the existing equipment, interface and application showing the reasons for our decisions to move to PC-DMIS and LabVIEW. A comparison between the new and legacy system is made

  3. The ATLAS Semiconductor Tracker: operations and performance

    CERN Document Server

    Pani, P; The ATLAS collaboration

    2013-01-01

    After more than 3 years of successful operation at 2 the LHC, we report on the operation and performance of the Semi-Conductor Tracker (SCT) functioning in a high luminosity, 4 high radiation environment. The SCT is part of the inner tracking system of the ATLAS 6 experiment at CERN and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. We find 99.3% of the 8 SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to 10 the ideal to allow on-line track reconstruction and invariant mass determination. We will report on the operation and performance 12 of the detector including an overview of the issues encountered. The observables employed to monitor online and offline the 14 quality and the performance of the data acquired by the SCT will be described and discussed.

  4. Performance of the ATLAS Inner Tracker

    CERN Document Server

    Marti-Garcia, S; The ATLAS collaboration

    2011-01-01

    ATLAS is a one of the four multipurpose experiments that records the products of the LHC proton-proton collisions at the LHC. In order to reconstruct the trajectories of charged particles, ATLAS is equipped, among others, with an inner charged particle tracking system built on two different technologies on silicon planar sensors (pixel and microstrips) plus drift-tube based detectors, all embedded in a 2 T solenoidal field. In order to achieve its scientific goals, ATLAS has quite demanding tracking performance requirements. Therefore, ATLAS is equipped, among others, with a charged particle tracking system built on two different technologies: silicon planar sensors and drift-tube based detectors constituting the ATLAS Inner Detector (ID). The ATLAS ID consists of about 6000 modules in its Silicon Tracker combined with several hundred drift tube based detector modules. The silicon modules use both technologies: pixel and microstrip. Pixel modules determine the position of passing particle tracks with an accur...

  5. Setup for testing LHCb Inner Tracker ladders

    CERN Document Server

    Vasquez Regueiro, P; Voss, H; Nicolas, L

    2007-01-01

    The Inner Tracker of the LHCb experiment is a silicon microstrip detector consisting of 336 detector modules with either one or two sensors. The module production is now underway and we present here the setup employed for module testing during the production. The setup is based on the same electronics that will be used in the final experiment. We perform burn-in and ageing tests with the help of a custom made Temperature Cycling Box controlled with LabVIEW under Windows. The DAQ is done in another PC running Linux. Here we integrate the different C/C++ libraries used to communicate to the LHCb Time and Fast Control system, Experiment Control System and Data Acquisition.

  6. 3D Technology for intelligent trackers

    Energy Technology Data Exchange (ETDEWEB)

    Lipton, Ronald; /Fermilab

    2010-09-01

    At Super-LHC luminosity it is expected that the standard suite of level 1 triggers for CMS will saturate. Information from the tracker will be needed to reduce trigger rates to satisfy the level 1 bandwidth. Tracking trigger modules which correlate information from closely-spaced sensor layers to form an on-detector momentum filter are being developed by several groups. We report on a trigger module design which utilizes three dimensional integrated circuit technology incorporating chips which are connected both to the top and bottom sensor, providing the ability to filter information locally. A demonstration chip, the VICTR, has been submitted to the Chartered/Tezzaron two-tier 3D run coordinated by Fermilab. We report on the 3D design concept, the status of the VICTR chip and associated sensor integration utilizing oxide bonding.

  7. Operation and performance of the CMS tracker

    CERN Document Server

    Malberti, Martina

    2014-01-01

    The CMS silicon tracker is the largest silicon detector ever built. It consists of an inner pixel detector, with 66 million readout channels, and an outer 200 m$^{2}$ silicon strip detector with 10 million channels. The successful operation of this detector during the first three years of LHC running with proton-proton and heavy ion collisions is discussed. Results include operational challenges encountered during data taking that influenced the active fraction and readout efficiency of the detectors. Details are given on the performance at high occupancy with respect to local observables, such as signal-to-noise ratio and hit reconstruction efficiency, and on radiation effects with respect to the evolution of power consumption, sensor bias, readout thresholds and leakage current.

  8. Ageing of the LHCb outer tracker

    CERN Document Server

    Blom, M R

    2009-01-01

    The modules of the LHCb outer tracker have shown to suffer severe gain loss under moderate irradiation. This process is called ageing. Ageing of the modules results from contamination of the gas system by glue, araldite AY 103-1, used in their construction. In this thesis the ageing process will be shown. The schemes known to reduce, reverse, or prevent ageing have been investigated to determine their effect on the detector performance. The addition of O2 to the gas mixture lowers the detector response by an acceptable amount and does not affect the gas transport properties significantly. The ageing rate is decreased after extensive flushing and HV training could eventually repair the irradiation damage. The risks of HV training have been assessed. Furthermore, several gaseous and aquatic additions have been tested for their capability to prevent, or moderate ageing, but none showed significant improvement.

  9. Radiation hardness of the LHCb Outer Tracker

    International Nuclear Information System (INIS)

    This paper presents results on the radiation hardness of the LHCb Outer Tracker (OT) during LHC operation in 2010 and 2011. Modules of the OT have shown to suffer from ageing effects that lead to gain loss, after irradiation in the laboratory. Under irradiation at moderate intensities an insulating layer is formed on the anode wire of the OT straw cells. This ageing effect is caused by contamination of the counting gas due to outgassing of the glue used in the construction of the OT modules. Two methods to monitor gain stability in the OT are presented: module scans with radioactive sources and the study of hit efficiency as a function of amplifier threshold. No gain loss is observed after receiving 1.3 fb−1 of integrated luminosity corresponding to an integrated charge of 0.055 C/cm in the hottest spot of the detector.

  10. Autonomous vision in space, based on Advanced Stellar Compass platform

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Eisenman, Allan R.; Liebe, Carl Christian

    1996-01-01

    The Ørsted Star Imager, comprises the functionality of an Advanced Stellar Compass (ASC). I.e. it is able to, autonomously solve "the lost in space" attitude problem, as well as determine the attitude with high precision in the matter of seconds. The autonomy makes for a high capability for error...

  11. Engineering Autonomous Driving Software

    OpenAIRE

    Berger, Christian; Rumpe, Bernhard

    2014-01-01

    A larger number of people with heterogeneous knowledge and skills running a project together needs an adaptable, target, and skill-specific engineering process. This especially holds for a project to develop a highly innovative, autonomously driving vehicle to participate in the 2007 DARPA Urban Challenge. In this contribution, we present essential elements of a software and systems engineering process to develop a so-called artificial intelligence capable of driving autonomously in complex u...

  12. Test of the Inner Tracker Silicon Microstrip Modules

    CERN Document Server

    Albergo, Sebastiano; Azzurri, Paolo; Bagliesi, Giuseppe; Bellan, Riccardo; Benedetti, Daniele; Benotto, Franco; Benucci, Leonardo; Bernardini, Jacopo; Bonato, Alessio; Brasolin, A; Chiorboli, Massimiliano; Civinini, Carlo; Costa, Marco; Creanza, Donato; D'Alfonso, Mariarosaria; De Palma, Mauro; Dell'Orso, Roberto; Demaria, Natale; Fiore, Luigi; Foà, Lorenzo; Galanti, Mario; Gatto Rotondo, Giuliana; Gerbaudo, Davide; Giammanco, Andrea; Giordano, Domenico; Kaminski, A; Karaevski, S; Lenzi, Piergiulio; Ligabue, Franco; Loreti, Maurizio; Mangano, Boris; Manolescu, Florentina; Marchettini, Cristiano; Meschini, Marco; Migliore, Ernesto; My, Salvatore; Preda, M; Radicci, Valeria; Ranieri, Riccardo; Reznikov, Sergey; Rizzi, Andrea; Saizu, Mirela Angela; Santocchia, Attilio; Segneri, Gabriele; Sguazzoni, Giacomo; Spagnolo, Paolo; Tenchini, Roberto; Tricomi, Alessia; Venturi, Andrea

    2009-01-01

    The inner portion of the CMS microstrip Tracker consists of 3540 silicon detector modules; its construction has been under full responsibility of seven INFN (Istituto Nazionale di Fisica Nucleare) and University laboratories in Italy. In this note procedures and strategies, which were developed and perfected to qualify the Tracker Inner Barrel and Inner Disks modules for installation, are described. In particular the tests required to select highly reliable detector modules are illustrated and a summary of the results from the full Inner Tracker module test is presented.

  13. New technologies in the D0 central tracker upgrade

    International Nuclear Information System (INIS)

    The D0 collaboration has undertaken an aggressive upgrade of its central tracking system. The existing tracker will be completely removed and replaced by a two Tesla superconducting solenoidal magnet, an 837 000 channel silicon vertex system, and 80 000 channel scintillating fiber tracker, followed by a 7 680 channel central preshower detector and a 16 000 channel forward preshower detector. In this paper the author discusses all of the subsystems of the D0 central tracker upgrade, but will emphasize those aspects which involve new technology: radiation hard scintillating fiber, VLPC's and extruded scintillating strips

  14. Simulation of the GEM central tracker performance using GEANT

    International Nuclear Information System (INIS)

    The GEM (Gamma Electron Muon) central tracker (one of the proposed detectors for the Superconducting Supercollider (SSC)) has been simulated using the high energy physics Monte Carlo code GEANT. The performance of the GEM central tracker in terms of momentum, impact parameter, and z vertex resolution has been determined. The resolutions will be presented for both the full tracker which includes a silicon portion and an IPC portion and for the 1034 configuration which is comprised of only IPC chambers. The resolution of electrons vs. muons will also be presented

  15. Architecture of autonomous systems

    Science.gov (United States)

    Dikshit, Piyush; Guimaraes, Katia; Ramamurthy, Maya; Agrawala, Ashok; Larsen, Ronald L.

    1989-01-01

    Automation of Space Station functions and activities, particularly those involving robotic capabilities with interactive or supervisory human control, is a complex, multi-disciplinary systems design problem. A wide variety of applications using autonomous control can be found in the literature, but none of them seem to address the problem in general. All of them are designed with a specific application in mind. In this report, an abstract model is described which unifies the key concepts underlying the design of automated systems such as those studied by the aerospace contractors. The model has been kept as general as possible. The attempt is to capture all the key components of autonomous systems. With a little effort, it should be possible to map the functions of any specific autonomous system application to the model presented here.

  16. Exercise and autonomic function.

    Science.gov (United States)

    Goldsmith, R L; Bloomfield, D M; Rosenwinkel, E T

    2000-03-01

    The complex interplay between the dichotomous subdivisions of the autonomic nervous system establishes and maintains a delicately tuned homeostasis in spite of an ever-changing environment. Aerobic exercise training can increase activity of the parasympathetic nervous system and decrease sympathetic activity. Conversely, it is well-documented that cardiac disease is often characterized by attenuated parasympathetic activity and heightened sympathetic tone. A correlation between autonomic disequilibrium and disease has led to the hypothesis that exercise training, as a therapy that restores the autonomic nervous system towards normal function, may be associated with, and possibly responsible for, outcome improvements in various populations. This is merely one of the many benefits that is conferred by chronic exercise training and reviewed in this issue. PMID:10758814

  17. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    Chalupkova, I; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector (ID) of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules with a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each side of the barrel). The SCT silicon microstrip sensors are processed in the planar p-in-n technology. The signals from the strips are processed in the front-end ASICs ABCD3TA, working in the binary readout mode. Data is transferred to the off-detector readout electronics via optical fibres. SCT has been installed inside the ATLAS experimental cavern since 2007 and has been operational ever since. Calibration data has been taken regularly and analysed to determine the noise performance of the system. ...

  18. ATLAS Silicon Microstrip Tracker: Operation and Performance

    CERN Document Server

    Mitsou, V A; The ATLAS collaboration

    2011-01-01

    The Semi-Conductor Tracker (SCT), is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two macro-structures: one barrel and two end-cap. The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals from the strips are processed in the front-end ASICs ABCD3TA, working in the binary readout mode. Data is transferred to the off-detector readout electronics via optical fibers. The completed SCT has been installed inside the ATLAS experimental cavern since 2007 and has been operational since then. Calibration data has been taken regularly and analyzed to determine the noise performance of the system. Extensive commissioning with cosmic ray events has b...

  19. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    Robinson, Dave; The ATLAS collaboration

    2011-01-01

    The Semi-Conductor Tracker (SCT), is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two macro-structures: one barrel and two end-cap. The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals from the strips are processed in the front-end ASICS ABCD3TA, working in the binary readout mode. Data is transferred to the off-detector readout electronics via optical fibers. The completed SCT has been installed inside the ATLAS experimental cavern since 2007 and has been operational since then. Calibration data has been taken regularly and analyzed to determine the noise performance of the system. Extensive commissioning with cosmic ray events has b...

  20. Climate Action Tracker Update. Climate Shuffle

    Energy Technology Data Exchange (ETDEWEB)

    Hoehne, N.; Fekete, H.; Vieweg, M.; Hare, B.; Schaeffer, M.; Rocha, M.; Larkin, J.; Guetschow, J.; Jeffery, L.

    2011-11-15

    The Climate Action Tracker (CAT) compares and assesses national and global action against a range of different climate targets across all relevant time frames, starting with an ongoing analysis of countries' current emission reduction pledges. National action on climate change mitigation appears to be joining the international climate negotiations in the new and ever popular 'climate shuffle' dance. It involves maximum effort and motion while staying in the same spot, or even, in some cases, going backwards. Recent emissions trends and estimates of the effects of those policies in place and proposed lead to a new estimate that warming is likely to approach 4C by 2100, significantly above the warming that would result from full implementation of the pledges (3.3C). The continuous global fossil-fuel intensive development of the past decade suggests that high warming levels of 4C are more plausible than assuming full implementation of current pledges. Evidence is ever increasing that existing and planned policies are not sufficient for countries to meet these pledges.

  1. 3D Monitoring of LHCb Inner Tracker

    CERN Multimedia

    Sainvitu, Pascal

    2015-01-01

    The positions of the Inner Tracker (IT) detectors of the LHCb experiment installed in the LHC at CERN are impacted by the LHCb dipole magnet powering. In the past the movements of the stations have been measured using standard survey methods during magnet tests in shutdown periods. But the survey targets are visible only in very narrow spaces and the access to the IT is very difficult, even impossible in the central region when the detector is closed. Finally the precision of the standard survey measurement is affected by the poor configuration. In 2013 and 2014, during the first long shutdown of the LHC (LS1), the CERN Survey team (EN/MEF-SU) in collaboration with the LHCb Technical Coordination and the EPFL (Ecole Polytechnique Fédérale de LAUSANNE, CH), developed a permanent monitoring system which has been tested and installed in order to allow the 3D position measurement of the IT stations, even during the run periods, with a precision of 100 microns at 1 sigma level. The 3D Monitoring system of the LH...

  2. The Tracker in the Trigger of LHCb

    CERN Document Server

    Hommels, L B A; Merk, M; Tuning, N

    2006-01-01

    Situated at the LHC, the LHCb experiment is to measure B meson decay with high statistics. Its primary goals are the establishment of CP violation parameters with high precision, and the study of rare B meson decays to look for physics processes beyond the Standard Model. In this thesis, an overview is given on the Outer Tracker (OT) subdetector of the LHCb experiment. The requirements on efficiency, resolution, occupancy and radiation hardness are discussed. The detector design and readout electronics of the OT, a gas filled detector, are presented. To meet the requirements, straw tube cathodes of 4.9mm inner diameter surround the anode wires. The tubes are filled with an Argon based counting gas at atmospheric pressure, allowing for a channel resolution better then 200mum. To limit multiple scattering, the OT is built from lightweight composite materials, resulting in a momentum resolution of dp/p < 0.6% for p between 0 and 150 GeV/c. From extensive ageing tests involving single channels as well as entir...

  3. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    Barone, G; The ATLAS collaboration

    2013-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices of the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of $4088$ silicon detector modules for a total of 6.3 million channels. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel ($4$ cylinders) and two end-cap systems (9 disks on each). The current results from the successful operation of the SCT Detector at the LHC and its status after three years of operation will be presented. The operation of the detector including an overview of the main issues encountered is reported. The main emphasis is be given to the tracking performance of the SCT and the data quality during the $>2$ years of data taking of proton-proton collision data at $7$ TeV (and short periods of heavy ion collisions). The SCT has been fully operational throughout a...

  4. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    Chalupkova, I; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals from the strips are processed in the front-end ASICS ABCD3TA, working in the binary readout mode. Data is transferred to the off-detector readout electronics via optical fibers. The completed SCT has been installed inside the ATLAS experimental cavern since 2007 and has been operational since then. Calibration data has been taken regularly and analyzed to determine the noise performance of the ...

  5. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    NAGAI, K; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals from the strips are processed in the front-end ASICS ABCD3TA, working in the binary readout mode. Data is transferred to the off-detector readout electronics via optical fibres. The completed SCT has been installed inside the ATLAS experimental cavern since 2007 and has been operational since then. Calibration data has been taken regularly and analysed to determine the noise performance of the ...

  6. The ATLAS semiconductor tracker: operations and performance

    CERN Document Server

    D'Auria, S; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar {it p}-in-{it n} technology. The signals are processed in the front-end ASICS ABCD3TA, working in binary readout mode. Data is transferred to the off-detector readout electronics via optical fibres. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications. In the talk the current results from the successful operation of the SCT Detector at the LHC and its status af...

  7. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    Barone, G; The ATLAS collaboration

    2013-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). In the talk the current results from the successful operation of the SCT Detector at the LHC and its status after three years of operation will be presented. We will report on the operation of the detector including an overview of the issues we encountered and the observation of significant increases in leakage currents (as expected) from bulk damage due to non-ionising radiation. The main emphasis will be given to the tracking performance of the SCT and the data quality during the >2 ye...

  8. The Fast Tracker Real Time Processor

    CERN Document Server

    Annovi, A; The ATLAS collaboration

    2011-01-01

    As the LHC luminosity is ramped up to the SLHC Phase I level and beyond, the high rates, multiplicities, and energies of particles seen by the detectors will pose a unique challenge. Only a tiny fraction of the produced collisions can be stored on tape and immense real-time data reduction is needed. An effective trigger system must maintain high trigger efficiencies for the physics we are most interested in, and at the same time suppress the enormous QCD backgrounds. This requires massive computing power to minimize the online execution time of complex algorithms. A multi-level trigger is an effective solution for an otherwise impossible problem. The Fast Tracker (FTK)[1], is a proposed upgrade to the current ATLAS trigger system that will operate at full Level-1 output rates and provide high quality tracks reconstructed over the entire detector by the start of processing in Level-2. FTK solves the combinatorial challenge inherent to tracking by exploiting massive parallelism of associative memories [2] that ...

  9. ATLAS silicon microstrip tracker operation and performance

    Science.gov (United States)

    Barone, Gaetano

    2013-12-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices of the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million channels. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each). The current results from the successful operation of the SCT Detector at the LHC and its status after three years of operation will be presented. The operation of the detector including an overview of the main issues encountered is reported. The main emphasis is given to the tracking performance of the SCT and the data quality during the >2 years of data taking of proton-proton collision data at 7 TeV (and short periods of heavy ion collisions). The SCT has been fully operational throughout all data taking periods, delivering high quality tracking data.

  10. Tracker electronics testing at Imperial College London

    CERN Multimedia

    PPARC, UK

    2006-01-01

    Jonathon Fulcher and Rob Bainbridge testing a rack of CMS Tracker readout electronics at Imperial College London. The signals from the front end APV chips will be transmitted optically to racks of electronics ~100m away in an adjacent underground cavern where they are fed into ~20 crates where 500 CMS Front End Driver boards (FEDs) are located. The FED inputs are 8 fibre ribbons, each ribbon consisting of 12 fibres, each fibre carrying the serially multiplexed data originating from 2 APVs. To test the FEDs special tester boards have been designed to produce simulated APV data in optical form. In the picture the yellow cables are the fibres, which originate from the FED tester boards on the left hand side of the crate as 96 individual fibres, which are then combined into the 8 fibre ribbons feeding the FED board on the right hand side of the crate. Fig. 2 shows an APV25 test board mounted in the X-ray irradiation setup, Fig. 3 the X-ray machine where the chips are irradiated and Fig. 4 the MGPA (Multi-Gain Pre...

  11. Performance studies of the CMS Strip Tracker before installation

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; et al.

    2009-06-01

    In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to understand the efficiency and alignment of the strip tracker modules, a cosmic ray trigger was implemented. From March through July 4.5 million triggers were recorded. This period, referred to as the Sector Test, provided practical experience with the operation of the Tracker, especially safety, data acquisition, power, and cooling systems. This paper describes the performance of the strip system during the Sector Test, which consisted of five distinct periods defined by the coolant temperature. Significant emphasis is placed on comparisons between the data and results from Monte Carlo studies.

  12. Data acquisition software for the CMS strip tracker

    CERN Document Server

    Bainbridge, R; Bel, S; Cole, J; Cripps, N; Delaere, C; Jesus, A C A; Drouhin, F; Fulcher, J; Giassi, A; Gill, K; Giordano, D; Gross, L; Hahn, K; Mersi, S; Mirabito, L; Nikolic, M; Radicci, V; Tkaczyk, S; Wingham, M

    2008-01-01

    The CMS silicon strip tracker, providing a sensitive area of approximately 200 m2 and comprising 10 million readout channels, has recently been completed at the tracker integration facility at CERN. The strip tracker community is currently working to develop and integrate the online and offline software frameworks, known as XDAQ and CMSSW respectively, for the purposes of data acquisition and detector commissioning and monitoring. Recent developments have seen the integration of many new services and tools within the online data acquisition system, such as event building, online distributed analysis, an online monitoring framework, and data storage management. We review the various software components that comprise the strip tracker data acquisition system, the software architectures used for stand-alone and global data-taking modes. Our experiences in commissioning and operating one of the largest ever silicon micro-strip tracking systems are also reviewed.

  13. Performance studies of the CMS Strip Tracker before installation

    CERN Document Server

    Adam, Wolfgang; Dragicevic, Marko; Friedl, Markus; Fruhwirth, R; Hansel, S; Hrubec, Josef; Krammer, Manfred; Oberegger, Margit; Pernicka, Manfred; Schmid, Siegfried; Stark, Roland; Steininger, Helmut; Uhl, Dieter; Waltenberger, Wolfgang; Widl, Edmund; Van Mechelen, Pierre; Cardaci, Marco; Beaumont, Willem; de Langhe, Eric; de Wolf, Eddi A; Delmeire, Evelyne; Hashemi, Majid; Bouhali, Othmane; Charaf, Otman; Clerbaux, Barbara; Dewulf, Jean-Paul; Elgammal, Sherif; Hammad, Gregory Habib; de Lentdecker, Gilles; Marage, Pierre Edouard; Vander Velde, Catherine; Vanlaer, Pascal; Wickens, John; Adler, Volker; Devroede, Olivier; De Weirdt, Stijn; D'Hondt, Jorgen; Goorens, Robert; Heyninck, Jan; Maes, Joris; Mozer, Matthias Ulrich; Tavernier, Stefaan; Van Lancker, Luc; Van Mulders, Petra; Villella, Ilaria; Wastiels, C; Bonnet, Jean-Luc; Bruno, Giacomo; De Callatay, Bernard; Florins, Benoit; Giammanco, Andrea; Gregoire, Ghislain; Keutgen, Thomas; Kcira, Dorian; Lemaitre, Vincent; Michotte, Daniel; Militaru, Otilia; Piotrzkowski, Krzysztof; Quertermont, L; Roberfroid, Vincent; Rouby, Xavier; Teyssier, Daniel; Daubie, Evelyne; Anttila, Erkki; Czellar, Sandor; Engstrom, Pauli; Harkonen, J; Karimaki, V; Kostesmaa, J; Kuronen, Auli; Lampen, Tapio; Linden, Tomas; Luukka, Panja-Riina; Maenpaa, T; Michal, Sebastien; Tuominen, Eija; Tuominiemi, Jorma; Ageron, Michel; Baulieu, Guillaume; Bonnevaux, Alain; Boudoul, Gaelle; Chabanat, Eric; Chabert, Eric Christian; Chierici, Roberto; Contardo, Didier; Della Negra, Rodolphe; Dupasquier, Thierry; Gelin, Georges; Giraud, Noël; Guillot, Gérard; Estre, Nicolas; Haroutunian, Roger; Lumb, Nicholas; Perries, Stephane; Schirra, Florent; Trocme, Benjamin; Vanzetto, Sylvain; Agram, Jean-Laurent; Blaes, Reiner; Drouhin, Frédéric; Ernenwein, Jean-Pierre; Fontaine, Jean-Charles; Berst, Jean-Daniel; Brom, Jean-Marie; Didierjean, Francois; Goerlach, Ulrich; Graehling, Philippe; Gross, Laurent; Hosselet, J; Juillot, Pierre; Lounis, Abdenour; Maazouzi, Chaker; Olivetto, Christian; Strub, Roger; Van Hove, Pierre; Anagnostou, Georgios; Brauer, Richard; Esser, Hans; Feld, Lutz; Karpinski, Waclaw; Klein, Katja; Kukulies, Christoph; Olzem, Jan; Ostapchuk, Andrey; Pandoulas, Demetrios; Pierschel, Gerhard; Raupach, Frank; Schael, Stefan; Schwering, Georg; Sprenger, Daniel; Thomas, Maarten; Weber, Markus; Wittmer, Bruno; Wlochal, Michael; Beissel, Franz; Bock, E; Flugge, G; Gillissen, C; Hermanns, Thomas; Heydhausen, Dirk; Jahn, Dieter; Kaussen, Gordon; Linn, Alexander; Perchalla, Lars; Poettgens, Michael; Pooth, Oliver; Stahl, Achim; Zoeller, Marc Henning; Buhmann, Peter; Butz, Erik; Flucke, Gero; Hamdorf, Richard Helmut; Hauk, Johannes; Klanner, Robert; Pein, Uwe; Schleper, Peter; Steinbruck, G; Blum, P; De Boer, Wim; Dierlamm, Alexander; Dirkes, Guido; Fahrer, Manuel; Frey, Martin; Furgeri, Alexander; Hartmann, Frank; Heier, Stefan; Hoffmann, Karl-Heinz; Kaminski, Jochen; Ledermann, Bernhard; Liamsuwan, Thiansin; Muller, S; Muller, Th; Schilling, Frank-Peter; Simonis, Hans-Jürgen; Steck, Pia; Zhukov, Valery; Cariola, P; De Robertis, Giuseppe; Ferorelli, Raffaele; Fiore, Luigi; Preda, M; Sala, Giuliano; Silvestris, Lucia; Tempesta, Paolo; Zito, Giuseppe; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Giordano, Domenico; Maggi, Giorgio; Manna, Norman; My, Salvatore; Selvaggi, Giovanna; Albergo, Sebastiano; Chiorboli, Massimiliano; Costa, Salvatore; Galanti, Mario; Giudice, Nunzio; Guardone, Nunzio; Noto, Francesco; Potenza, Renato; Saizu, Mirela Angela; Sparti, V; Sutera, Concetta; Tricomi, Alessia; Tuve, Cristina; Brianzi, Mirko; Civinini, Carlo; Maletta, Fernando; Manolescu, Florentina; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Broccolo, B; Ciulli, Vitaliano; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Genta, Chiara; Landi, Gregorio; Lenzi, Piergiulio; Macchiolo, Anna; Magini, Nicolo; Parrini, Giuliano; Scarlini, Enrico; Cerati, Giuseppe Benedetto; Azzi, Patrizia; Bacchetta, Nicola; Candelori, Andrea; Dorigo, Tommaso; Kaminsky, A; Karaevski, S; Khomenkov, Volodymyr; Reznikov, Sergey; Tessaro, Mario; Bisello, Dario; De Mattia, Marco; Giubilato, Piero; Loreti, Maurizio; Mattiazzo, Serena; Nigro, Massimo; Paccagnella, Alessandro; Pantano, Devis; Pozzobon, Nicola; Tosi, Mia; Bilei, Gian Mario; Checcucci, Bruno; Fano, Livio; Servoli, Leonello; Ambroglini, Filippo; Babucci, Ezio; Benedetti, Daniele; Biasini, Maurizio; Caponeri, Benedetta; Covarelli, Roberto; Giorgi, Marco; Lariccia, Paolo; Mantovani, Giancarlo; Marcantonini, Marta; Postolache, Vasile; Santocchia, Attilio; Spiga, Daniele; Bagliesi, Giuseppe; Balestri, Gabriele; Berretta, Luca; Bianucci, S; Boccali, Tommaso; Bosi, Filippo; Bracci, Fabrizio; Castaldi, Rino; Ceccanti, Marco; Cecchi, Roberto; Cerri, Claudio; Cucoanes, Andi Sebastian; Dell'Orso, Roberto; Dobur, Didar; Dutta, Suchandra; Giassi, Alessandro; Giusti, Simone; Kartashov, Dmitry; Kraan, Aafke; Lomtadze, Teimuraz; Lungu, George-Adrian; Magazzu, Guido; Mammini, Paolo; Mariani, Filippo; Martinelli, Giovanni; Moggi, Andrea; Palla, Fabrizio; Palmonari, Francesco; Petragnani, Giulio; Profeti, Alessandro; Raffaelli, Fabrizio; Rizzi, Domenico; Sanguinetti, Giulio; Sarkar, Subir; Sentenac, Daniel; Serban, Alin Titus; Slav, Adrian; Soldani, A; Spagnolo, Paolo; Tenchini, Roberto; Tolaini, Sergio; Venturi, Andrea; Verdini, Piero Giorgio; Vos, Marcel; Zaccarelli, Luciano; Avanzini, Carlo; Basti, Andrea; Benucci, Leonardo; Bocci, Andrea; Cazzola, Ugo; Fiori, Francesco; Linari, Stefano; Massa, Maurizio; Messineo, Alberto; Segneri, Gabriele; Tonelli, Guido; Azzurri, Paolo; Bernardini, Jacopo; Borrello, Laura; Calzolari, Federico; Foa, Lorenzo; Gennai, Simone; Ligabue, Franco; Petrucciani, Giovanni; Rizzi, Andrea; Yang, Zong-Chang; Benotto, Franco; Demaria, Natale; Dumitrache, Floarea; Farano, R; Borgia, Maria Assunta; Castello, Roberto; Costa, Marco; Migliore, Ernesto; Romero, Alessandra; Abbaneo, Duccio; Abbas, M; Ahmed, Ijaz; Akhtar, I; Albert, Eric; Bloch, Christoph; Breuker, Horst; Butt, Shahid Aleem; Buchmuller, Oliver; Cattai, Ariella; Delaere, Christophe; Delattre, Michel; Edera, Laura Maria; Engstrom, Pauli; Eppard, Michael; Gateau, Maryline; Gill, Karl; Giolo-Nicollerat, Anne-Sylvie; Grabit, Robert; Honma, Alan; Huhtinen, Mika; Kloukinas, Kostas; Kortesmaa, Jarmo; Kottelat, Luc-Joseph; Kuronen, Auli; Leonardo, Nuno; Ljuslin, Christer; Mannelli, Marcello; Masetti, Lorenzo; Marchioro, Alessandro; Mersi, Stefano; Michal, Sebastien; Mirabito, Laurent; Muffat-Joly, Jeannine; Onnela, Antti; Paillard, Christian; Pal, Imre; Pernot, Jean-Francois; Petagna, Paolo; Petit, Patrick; Piccut, C; Pioppi, Michele; Postema, Hans; Ranieri, Riccardo; Ricci, Daniel; Rolandi, Gigi; Ronga, Frederic Jean; Sigaud, Christophe; Syed, A; Siegrist, Patrice; Tropea, Paola; Troska, Jan; Tsirou, Andromachi; Vander Donckt, Muriel; Vasey, François; Alagoz, Enver; Amsler, Claude; Chiochia, Vincenzo; Regenfus, Christian; Robmann, Peter; Rochet, Jacky; Rommerskirchen, Tanja; Schmidt, Alexander; Steiner, Stefan; Wilke, Lotte; Church, Ivan; Cole, Joanne; Coughlan, John A; Gay, Arnaud; Taghavi, S; Tomalin, Ian R; Bainbridge, Robert; Cripps, Nicholas; Fulcher, Jonathan; Hall, Geoffrey; Noy, Matthew; Pesaresi, Mark; Radicci, Valeria; Raymond, David Mark; Sharp, Peter; Stoye, Markus; Wingham, Matthew; Zorba, Osman; Goitom, Israel; Hobson, Peter R; Reid, Ivan; Teodorescu, Liliana; Hanson, Gail; Jeng, Geng-Yuan; Liu, Haidong; Pasztor, Gabriella; Satpathy, Asish; Stringer, Robert; Mangano, Boris; Affolder, K; Affolder, T; Allen, Andrea; Barge, Derek; Burke, Samuel; Callahan, D; Campagnari, Claudio; Crook, A; D'Alfonso, Mariarosaria; Dietch, J; Garberson, Jeffrey; Hale, David; Incandela, H; Incandela, Joe; Jaditz, Stephen; Kalavase, Puneeth; Kreyer, Steven Lawrence; Kyre, Susanne; Lamb, James; Mc Guinness, C; Mills, C; Nguyen, Harold; Nikolic, Milan; Lowette, Steven; Rebassoo, Finn; Ribnik, Jacob; Richman, Jeffrey; Rubinstein, Noah; Sanhueza, S; Shah, Yousaf Syed; Simms, L; Staszak, D; Stoner, J; Stuart, David; Swain, Sanjay Kumar; Vlimant, Jean-Roch; White, Dean; Ulmer, Keith; Wagner, Stephen Robert; Bagby, Linda; Bhat, Pushpalatha C; Burkett, Kevin; Cihangir, Selcuk; Gutsche, Oliver; Jensen, Hans; Johnson, Mark; Luzhetskiy, Nikolay; Mason, David; Miao, Ting; Moccia, Stefano; Noeding, Carsten; Ronzhin, Anatoly; Skup, Ewa; Spalding, William J; Spiegel, Leonard; Tkaczyk, Slawek; Yumiceva, Francisco; Zatserklyaniy, Andriy; Zerev, E; Anghel, Ioana Maria; Bazterra, Victor Eduardo; Gerber, Cecilia Elena; Khalatian, S; Shabalina, Elizaveta; Baringer, Philip; Bean, Alice; Chen, Jie; Hinchey, Carl Louis; Martin, Christophe; Moulik, Tania; Robinson, Richard; Gritsan, Andrei; Lae, Chung Khim; Tran, Nhan Viet; Everaerts, Pieter; Hahn, Kristan Allan; Harris, Philip; Nahn, Steve; Rudolph, Matthew; Sung, Kevin; Betchart, Burton; Demina, Regina; Gotra, Yury; Korjenevski, Sergey; Miner, Daniel Carl; Orbaker, Douglas; Christofek, Leonard; Hooper, Ryan; Landsberg, Greg; Nguyen, Duong; Narain, Meenakshi; Speer, Thomas; Tsang, Ka Vang

    2009-01-01

    In March 2007 the assembly of the Silicon Strip Tracker was completed at the Tracker Integration Facility at CERN. Nearly 15% of the detector was instrumented using cables, fiber optics, power supplies, and electronics intended for the operation at the LHC. A local chiller was used to circulate the coolant for low temperature operation. In order to understand the efficiency and alignment of the strip tracker modules, a cosmic ray trigger was implemented. From March through July 4.5 million triggers were recorded. This period, referred to as the Sector Test, provided practical experience with the operation of the Tracker, especially safety, data acquisition, power, and cooling systems. This paper describes the performance of the strip system during the Sector Test, which consisted of five distinct periods defined by the coolant temperature. Significant emphasis is placed on comparisons between the data and results from Monte Carlo studies.

  14. The Data Quality Monitoring for the CMS Silicon Strip Tracker

    CERN Document Server

    Adler, V; Bainbridge, R; Benucci, L; Borgia, M A; Borrello, L; Cole, J; Cripps, N; Delmeire, E; Dero, V; Dutta, S; Giordano, D; Hammad, G H; Hashemi, H; Le Bihan, A C; Le Bourgeois, M; Palmonari, F; Pierro, A; Zito, G

    2009-01-01

    The CMS Silicon Strip Tracker (SST), consisting of more than 10 million channels, is organized in about 15,000 detector modules and it is the largest silicon strip tracker ever built for high energy physics experiments. The Data Quality Monitoring system for the Tracker has been developed within the CMS Software framework. More than 100,000 monitorable quantities need to be managed by the DQM system that organizes them in a hierarchical structure reflecting the detector arrangement in subcomponents and the various levels of data processing. Monitorable quantities computed at the level of individual detectors are processed to extract automatic quality checks and summary results that can be visualized with specialized graphical user interfaces. In view of the great complexity of the CMS Tracker detector the standard visualization tools based on histograms have been complemented with 2 and 3 dimensional graphical images of the subdetector that can show the whole detector down to single channel resolution. The fu...

  15. Expected performance of the ATLAS Inner Tracker upgrade

    CERN Document Server

    Viel, Simon; The ATLAS collaboration

    2016-01-01

    The design of the ATLAS Inner Tracker upgrade is underway. This tracking detector, consisting of silicon pixel and strip modules, will replace the current ATLAS Inner Detector to reconstruct tracks from charged particles produced at the very high collision rate expected from the High-Luminosity Large Hadron Collider. The latest Inner Tracker designs considered, and the most recent expected performance results from simulation are presented.

  16. Optimization of the silicon sensors for the CMS tracker

    CERN Document Server

    Albergo, S; Azzi, P; Babucci, E; Bacchetta, N; Bader, A J; Bagliesi, G; Basti, A; Biggeri, U; Biino, C; Bilei, G M; Bisello, D; Boemi, D; Bosi, F; Borello, L; Braibant, S; Breuker, Horst; Unettib, M T; Bruzzi, Mara; Buffini, A; Busoni, S; Candelori, A; Caner, A; Castaldi, R; Castro, A; Catacchini, E; Checcucci, B; Ciampolini, P; Civinini, C; Costa, M; Creanza, D; D'Alessandro, R; Demaria, N; De Palma, M; Dell'Orso, R; Dutta, S; Favro, G; Fiore, L; Focardi, E; French, M; Freudenreich, Klaus; Frey, A; Friedl, M; Fürtjes, A; Giassi, A; Giorgi, M A; Giraldo, A; Glessing, W D; Gu, W H; Hall, G; Hammarström, R; Hebbeker, T; Honkanen, A; Honma, A; Hrubec, Josef; Huhtinen, M; Kaminski, A; Karimäki, V; König, S; Krammer, Manfred; Lariccia, P; Lenzi, M; Loreti, M; Lübelsmeyer, K; Lustermann, W; Mättig, P; Maggi, G; Mannelli, M; Mantovani, G C; Marchioro, A; Mariotti, C; Martignon, G; McEvoy, B; Meschini, M; Messineo, A; Migliore, E; My, S; Neviani, A; Paccagella, A; Palla, Fabrizio; Pandoulas, D; Papi, A; Parrini, G; Passeri, D; Pernicka, Manfred; Pieri, M; Piperov, S; Potenza, R; Radicci, V; Raffaelli, F; Raymond, M; Siedling, R; Silvestris, L; Starodumov, Andrei; Stavitski, I; Surrow, B; Tempesta, P; Tonelli, G; Tricomi, A; Tuominiemi, Jorma; Tuuva, T; Verdini, P G; Viertel, Gert M; Xie, Z; Yahong, L; Watts, S; Wittmer, B

    2001-01-01

    The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R&D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker. (7 refs).

  17. Solar Panel Maximum Power Point Tracker for Power Utilities

    OpenAIRE

    Sandeep Banik,; Dr P.K.Saha

    2014-01-01

    ―Solar Panel Maximum Power Point Tracker For power utilities‖ As the name implied, it is a photovoltaic system that uses the photovoltaic array as a source of electrical power supply and since every photovoltaic (PV) array has an optimum operating point, called the maximum power point, which varies depending on the insolation level and array voltage. A maximum power point tracker (MPPT) is needed to operate the PV array at its maximum power point. The objective of this thesis...

  18. HCPV trackers arrangement based on space coordinate transformations

    Science.gov (United States)

    Mi, Zhe; Chen, Nuofu; Liu, Hu; Bai, Yiming; Zhang, Xiulan; Chen, Jikun; Wang, Xiangwu

    2014-09-01

    A new pattern of space coordinate system based on sun-tracking surface has been introduced in this paper. The calculation of shadow area between HCPV trackers has been simplified within this kind of coordinate system. The spaces between rows and columns of HCPV arrays can be calculated accurately. Therefore, an appropriate layout of trackers arrangement for a HCPV power plant can be determined and designed by use of this method.

  19. Launch strategy for a GPS-based package tracker product

    OpenAIRE

    Biermann, Jürgen

    2006-01-01

    The objective of this paper is to present a recommendation for a launch strategy for a new Package Tracker Product based on enhanced GPS location technology for a GPS software company, Guardian Mobile Monitoring Systems. We will first give an overview of Global Positioning System (GPS) technology and its more recent advancements and explain the potential for a package tracker product. Secondly, we will examine possible target market segments. Thirdly, we will perform an internal analysis of G...

  20. Wetland Tracker Data Collection Central Coast (Morro Bay Region)

    OpenAIRE

    Michie, Matthew; Watson, Fred; Casagrande, Joel

    2006-01-01

    The goal of this project was to gather information on wetland restoration projects in the Moro Bay, California, region. Data provided to the San Francisco Estuary Institute (SFEI) will be used to enhance a web-based, public access database, the Bay Area Wetland Project Tracker. Wetland Tracker provides information on the location, size, sponsors, habitats, contact persons, and status of included projects. Its website provides an interactive map of planned and completed wetland projects (ht...

  1. Design of a Solar Tracker System for PV Power Plants

    OpenAIRE

    Tiberiu Tudorache; Liviu Kreindler

    2010-01-01

    This paper deals with the design and execution of a solar tracker systemdedicated to the PV conversion panels. The proposed single axis solar tracker deviceensures the optimization of the conversion of solar energy into electricity by properlyorienting the PV panel in accordance with the real position of the sun. The operation of theexperimental model of the device is based on a DC motor intelligently controlled by adedicated drive unit that moves a mini PV panel according to the signals rece...

  2. Overview of the Autonomic Nervous System

    Science.gov (United States)

    ... reversible or progressive. Anatomy of the autonomic nervous system The autonomic nervous system is the part of ... they connect with. Function of the autonomic nervous system The autonomic nervous system controls internal body processes ...

  3. A Stellar Reference Unit Design Study for SIRTF

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Liebe, Carl Christian

    1996-01-01

    A design study for a stellar reference unit, or star tracker, for SIRTF was conducted in FY96 in conjunction with the Tracking Sensors Group of the Avionic Equipment Section of JPL. The resulting design was derived from the Oersted, autonomous, Advanced Stellar Compass, star tracker. The projected...... star tracker integration with the cryogenic telescope structure....

  4. Multi-expert tracking algorithm based on improved compressive tracker

    Science.gov (United States)

    Feng, Yachun; Zhang, Hong; Yuan, Ding

    2015-12-01

    Object tracking is a challenging task in computer vision. Most state-of-the-art methods maintain an object model and update the object model by using new examples obtained incoming frames in order to deal with the variation in the appearance. It will inevitably introduce the model drift problem into the object model updating frame-by-frame without any censorship mechanism. In this paper, we adopt a multi-expert tracking framework, which is able to correct the effect of bad updates after they happened such as the bad updates caused by the severe occlusion. Hence, the proposed framework exactly has the ability which a robust tracking method should process. The expert ensemble is constructed of a base tracker and its formal snapshot. The tracking result is produced by the current tracker that is selected by means of a simple loss function. We adopt an improved compressive tracker as the base tracker in our work and modify it to fit the multi-expert framework. The proposed multi-expert tracking algorithm significantly improves the robustness of the base tracker, especially in the scenes with frequent occlusions and illumination variations. Experiments on challenging video sequences with comparisons to several state-of-the-art trackers demonstrate the effectiveness of our method and our tracking algorithm can run at real-time.

  5. EMC Diagnosis and Corrective Actions for Silicon Strip Tracker Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Arteche, F.; /CERN /Imperial Coll., London; Rivetta, C.; /SLAC

    2006-06-06

    The tracker sub-system is one of the five sub-detectors of the Compact Muon Solenoid (CMS) experiment under construction at CERN for the Large Hadron Collider (LHC) accelerator. The tracker subdetector is designed to reconstruct tracks of charged sub-atomic particles generated after collisions. The tracker system processes analogue signals from 10 million channels distributed across 14000 silicon micro-strip detectors. It is designed to process signals of a few nA and digitize them at 40 MHz. The overall sub-detector is embedded in a high particle radiation environment and a magnetic field of 4 Tesla. The evaluation of the electromagnetic immunity of the system is very important to optimize the performance of the tracker sub-detector and the whole CMS experiment. This paper presents the EMC diagnosis of the CMS silicon tracker sub-detector. Immunity tests were performed using the final prototype of the Silicon Tracker End-Caps (TEC) system to estimate the sensitivity of the system to conducted noise, evaluate the weakest areas of the system and take corrective actions before the integration of the overall detector. This paper shows the results of one of those tests, that is the measurement and analysis of the immunity to CM external conducted noise perturbations.

  6. A Hardware Fast Tracker for the ATLAS Trigger: The Fast TracKer (FTK) Project.

    CERN Document Server

    Asbah, Nedaa; The ATLAS collaboration

    2015-01-01

    The trigger system of the ATLAS experiment is designed to reduce the event rate from the LHC nominal bunch crossing at 40 MHz to about 1 kHz, at the design luminosity of 10^{34} cm^{-2} s{-1}. After a successful period of data taking from 2010 to early 2013, the LHC is restarting in 2015 with much higher instantaneous luminosity and this will increase the load on High Level Trigger system, the second stage of the selection based on software algorithms. More sophisticated algorithms will be needed to achieve higher background rejection while maintaining good efficiency for interesting physics signals. The Fast TracKer is part of the ATLAS trigger upgrade project; it is a hardware processor that will provide, at every level-1 accept (100 kHz) and within 100 microseconds, full tracking information for tracks with momentum as low as 1 GeV. Providing fast extensive access to tracking information, with resolution comparable to the offline reconstruction, the Fast Tracker will for example help the High Level Trigger...

  7. Experimental Autonomous Vehicle Systems

    DEFF Research Database (Denmark)

    Ravn, Ole; Andersen, Nils Axel

    1998-01-01

    The paper describes the requirements for and a prototype configuration of a software architecture for control of an experimental autonomous vehicle. The test bed nature of the system is emphasised in the choice of architecture making re-configurability, data logging and extendability simple. The...

  8. ADAM: ADaptive Autonomous Machine

    NARCIS (Netherlands)

    Oosten, van Daan C.; Nijenhuis, Lucas F.J.; Bakkers, André W.P.; Vervoort, Wiek A.

    1996-01-01

    This paper describes a part of the development of an adaptive autonomous machine that is able to move in an unknown world extract knowledge out of the perceived data, has the possibility to reason, and finally has the capability to exchange experiences and knowledge with other agents. The agent is n

  9. Autonomous Security Patrol System

    OpenAIRE

    Erramouspe, Jake

    2010-01-01

    This project provides an efficient and cost-effective solution to building security and active monitoring. The security is monitored and controlled by autonomous patrol robots. Any indication of a security breach will result in an immediate alarm and activation of the robot group to subdue and tranquilize the intruder.

  10. Exploring new frontiers in nuclear and particle physics with the STAR detector at RHIC

    International Nuclear Information System (INIS)

    The Solenoidal Tracker At RHIC (STAR) is a large acceptance collider detector scheduled to begin operation at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in the fall of 1999. In the sections which follow, details of the STAR detector and physics program, as well as the status of the RHIC construction project will be presented

  11. Software Architecture for Autonomous Spacecraft

    Science.gov (United States)

    Shih, Jimmy S.

    1997-01-01

    The thesis objective is to design an autonomous spacecraft architecture to perform both deliberative and reactive behaviors. The Autonomous Small Planet In-Situ Reaction to Events (ASPIRE) project uses the architecture to integrate several autonomous technologies for a comet orbiter mission.

  12. The STAR Tracking Upgrade

    International Nuclear Information System (INIS)

    The STAR collaboration is preparing a tracking detector upgrade, the Heavy Flavor Tracker (HFT) and the Forward GEM Tracker (FGT) to further investigate fundamental properties of the new state of strongly interacting matter produced in relativistic-heavy ion collisions at RHIC and to provide fundamental studies of the proton spin structure and dynamics in high-energy polarized proton-proton collisions at RHIC. The HFT is based on a novel two-layer CMOS active-pixel sensor detector together with a conventional two-layer silicon-strip/silicon-pad detector. The FGT upgrade will consist of six triple-GEM detectors with two dimensional readout arranged in disks along the beam axis. The FGT project has completed an extensive R and D program of industrially produced GEM foils at Tech-Etch Inc. in comparison to GEM foils produced at CERN based on optical measurements, test beam and 55Fe source measurements of a triple-GEM prototype detector using 10 x 10 cm2 GEM foils. The FGT project requires large GEM foils which are currently being tested. The HFT and FGT design, the status of full prototype tests along with the HFT and FGT construction and the installation schedule will be presented. (author)

  13. The STAR TPC front end electronics

    International Nuclear Information System (INIS)

    The Solenoidal Tracker at RHIC (STAR) uses a large time projection chamber. Each of the 136,600 pads is instrumented with a waveform digitizer, implemented in custom low noise preamplifier/shaper and switched capacitor array/ADCs ICs. The system is highly integrated with all analog functions mounted on small cards that plug into the TPC. Detector mounted readout boards multiplex data from 1152 channels onto a 1.5 Gbit/sec fiber optic link to the data acquisition system

  14. Open charm measurement with HFT at STAR

    OpenAIRE

    Kapitan, Jan; Collaboration, for the STAR

    2008-01-01

    Thermalization is one of the key questions in understanding the matter created in Au+Au collisions at RHIC. Heavy-flavor quark collectivity could be used to indicate the degree of thermalization of the light-flavor quarks. Heavy quark energy loss could give important information on color charge density of the medium. Direct reconstruction of open charm hadrons is essential for these measurements. The Heavy Flavor Tracker (HFT) is a proposed upgrade of the STAR experiment. Full GEANT simulatio...

  15. MEVSIM: A Monte Carlo Event Generator for STAR

    OpenAIRE

    Ray, R. L.; Longacre, R. S.

    2000-01-01

    A fast, simple to use Monte Carlo based event generator is presented which is intended to facilitate simulation studies and the development of analysis software for the Solenoidal Tracker at RHIC (Relativistic Heavy Ion Collider) (STAR) experiment at the Brookhaven National Laboratory (BNL). This new event generator provides a fast, convenient means for producing large numbers of uncorrelated A+A collision events which can be used for a variety of applications in STAR, including quality assur...

  16. Overview of recent results from the STAR experiment

    OpenAIRE

    Mustafa, Mustafa

    2015-01-01

    The Solenoidal Tracker at RHIC (STAR) experiment utilizes its excellent mid-rapidity tracking and particle identification capabilities to study the emergent properties of Quantum Chromodynamics (QCD). The STAR heavy-ion program at vanishingly small baryon density is aimed to address questions about the quantitative properties of the strongly-interacting Quark Gluon Plasma (QGP) matter created in high energy collisions ($\\eta/s$, $\\hat{q}$, chirality, transport parameters, heavy quark diffusio...

  17. Mobile Autonomous Humanoid Assistant

    Science.gov (United States)

    Diftler, M. A.; Ambrose, R. O.; Tyree, K. S.; Goza, S. M.; Huber, E. L.

    2004-01-01

    A mobile autonomous humanoid robot is assisting human co-workers at the Johnson Space Center with tool handling tasks. This robot combines the upper body of the National Aeronautics and Space Administration (NASA)/Defense Advanced Research Projects Agency (DARPA) Robonaut system with a Segway(TradeMark) Robotic Mobility Platform yielding a dexterous, maneuverable humanoid perfect for aiding human co-workers in a range of environments. This system uses stereo vision to locate human team mates and tools and a navigation system that uses laser range and vision data to follow humans while avoiding obstacles. Tactile sensors provide information to grasping algorithms for efficient tool exchanges. The autonomous architecture utilizes these pre-programmed skills to form human assistant behaviors. The initial behavior demonstrates a robust capability to assist a human by acquiring a tool from a remotely located individual and then following the human in a cluttered environment with the tool for future use.

  18. Autonomous single camera exploration

    OpenAIRE

    Vidal-Calleja, Teresa A.; Sanfeliu, Alberto; Andrade-Cetto, J.

    2006-01-01

    In this paper we present an active exploration strategy for a mobile robot navigating in 3D. The aim is to control a moving robot that autonomously builds a visual feature map while at the same time optimises its localisation in this map. The technique chooses the most appropriate commands maximising the information gain between prior states and measurements, while performing 6DOF bearing only SLAM at video rate. Maximising the mutual information helps the vehicle avoid ill-conditioned measur...

  19. Autonomous Underwater Vehicle control

    OpenAIRE

    Vidal Morató, Jordi; Gomáriz Castro, Spartacus; Manuel Lázaro, Antonio

    2005-01-01

    In this paper the system control design stages for an autonomous underwater vehicle are presented. The vehicle must be able to sail on sea surface, following a path without losing its route and once a position is reached, a dive following a perpendicular path to the surface is carried out. A two level system control are proposed. The primary level will control the navigation of the vehicle where a linear controllers are proposed. Whereas in secondary level guidance system, collision system, s...

  20. The autonomous acoustic buoy

    OpenAIRE

    Pellicer, Francisco; Reitsma, Robert; Agüera, Joaquín; Marinas, Alexandra

    2013-01-01

    The Acoustic Buoy is a project between the Laboratory of Applied Bioacoustics (LAB) and the Universitat Politècnica de Catalunya (UPC). In areas that the human activities produce high noise levels, such as oil exploration or construction, there is a need to monitor the environment for the presence of cetaceans. Another need is for fishing, to prevent endangered species from being killed. This can be done with an Autonomous Acoustic Buoy (AAB). Mooring or anchoring at to the seaflo...

  1. Mobile Intelligent Autonomous Systems

    OpenAIRE

    Jitendra R. Raol; Ajith Gopal

    2010-01-01

    Mobile intelligent autonomous systems (MIAS) is a fast emerging research area. Although it can be regarded as a general R&D area, it is mainly directed towards robotics. Several important subtopics within MIAS research are:(i) perception and reasoning, (ii) mobility and navigation,(iii) haptics and teleoperation, (iv) image fusion/computervision, (v) modelling of manipulators, (vi) hardware/software architectures for planning and behaviour learning leadingto robotic architecture, (vii) ve...

  2. Software alignment of the LHCb Outer Tracker chambers

    Energy Technology Data Exchange (ETDEWEB)

    Deissenroth, Marc

    2010-04-21

    This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 {mu}m) for the translational degrees of freedom and of O(10{sup -2} - 10{sup -1} mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within {proportional_to} 90 {mu}m. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

  3. Advances in RGB and RGBD Generic Object Trackers

    KAUST Repository

    Bibi, Adel

    2016-04-01

    Visual object tracking is a classical and very popular problem in computer vision with a plethora of applications such as vehicle navigation, human computer interface, human motion analysis, surveillance, auto-control systems and many more. Given the initial state of a target in the first frame, the goal of tracking is to predict states of the target over time where the states describe a bounding box covering the target. Despite numerous object tracking methods that have been proposed in recent years [1-4], most of these trackers suffer a degradation in performance mainly because of several challenges that include illumination changes, motion blur, complex motion, out of plane rotation, and partial or full occlusion, while occlusion is usually the most contributing factor in degrading the majority of trackers, if not all of them. This thesis is devoted to the advancement of generic object trackers tackling different challenges through different proposed methods. The work presented propose four new state-of-the-art trackers. One of which is 3D based tracker in a particle filter framework where both synchronization and registration of RGB and depth streams are adjusted automatically, and three works in correlation filters that achieve state-of-the-art performance in terms of accuracy while maintaining reasonable speeds.

  4. Software alignment of the LHCb Outer Tracker chambers

    International Nuclear Information System (INIS)

    This work presents an alignment algorithm that was developed to precisely determine the positions of the LHCb Outer Tracker detector elements. The algorithm is based on the reconstruction of tracks and exploits that misalignments of the detector change the residual between a measured hit and the reconstructed track. It considers different levels of granularities of the Outer Tracker geometry and fully accounts for correlations of all elements which are imposed by particle trajectories. In extensive tests, simulated shifts and rotations for different levels of the detector granularity have been used as input to the track reconstruction and alignment procedure. With about 260 000 tracks the misalignments are recovered with a statistical precision of O(10 - 100 μm) for the translational degrees of freedom and of O(10-2 - 10-1 mrad) for rotations. A study has been performed to determine the impact of Outer Tracker misalignments on the performance of the track reconstruction algorithms. It shows that the achieved statistical precision does not decrease the track reconstruction performance in a significant way. During the commissioning of the LHCb detector, cosmic ray muon events have been collected. The events have been analysed and used for the first alignment of the 216 Outer Tracker modules. The module positions have been determined within ∝ 90 μm. The developed track based alignment algorithm has demonstrated its reliability and is one of the core algorithms which are used for the precise determination of the positions of the LHCb Outer Tracker elements. (orig.)

  5. Technical Training Seminar: Laser Trackers: the Local Positioning Technology (LPT)

    CERN Multimedia

    Davide Vitè

    2005-01-01

    Friday 20 May from 10:00 to 16:00, Training Centre (bldg. 593) Laser Trackers: the Local Positioning Technology (LPT) Simon Moser, Michael Lettau, Achim Lupus, Niklaus Suter, Leica GEOSYSTEMS AG, Switzerland Laser trackers are used at CERN for different applications within the LHC Project. Leica Geosystems AG have been developing during the last four years the revolutionary Local Positioning Technology (LPT). Laser trackers are increasingly used to ensure accuracy of large fabrications, and alignment in the final assembly process. Competing portable Coordinate Measuring Machines (CMM) with articulated arms require a frequent repositioning, known to lead to a loss of accuracy and efficiency. Leica Geosystems developed armless solutions, the T-Probe and T-Scan, for use with its laser trackers. The combination of the tracker technology with photogrammetry is the base of LPT, enabling real time measurements with free hand-held devices, such as the T-Probe and T-Scan. T-Probe and T-Scan overcome the proble...

  6. Nature's Autonomous Oscillators

    Science.gov (United States)

    Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

    2012-01-01

    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

  7. Trigeminal autonomic cephalalgias.

    Science.gov (United States)

    Eller, M; Goadsby, P J

    2016-01-01

    The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders characterised by lateralized symptoms: prominent headache and ipsilateral cranial autonomic features, such as conjunctival injection, lacrimation and rhinorrhea. The TACs are: cluster headache (CH), paroxysmal hemicrania (PH), short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)/short-lasting neuralgiform headache attacks with cranial autonomic features (SUNA) and hemicrania continua (HC). Their diagnostic criteria are outlined in the International Classification of Headache Disorders, third edition-beta (ICHD-IIIb). These conditions are distinguished by their attack duration and frequency, as well as response to treatment. HC is continuous and by definition responsive to indomethacin. The main differential when considering this headache is chronic migraine. Other TACs are remarkable for their short duration and must be distinguished from other short-lasting painful conditions, such as trigeminal neuralgia and primary stabbing headache. Cluster headache is characterised by exquisitely painful attacks that occur in discrete episodes lasting 15-180 min a few times a day. In comparison, PH occurs more frequently and is of shorter duration, and like HC is responsive to indomethacin. SUNCT/SUNA is the shortest duration and highest frequency TAC; attacks can occur over a hundred times every day. PMID:24888770

  8. STAR Upgrade Plan for the Coming Decade

    International Nuclear Information System (INIS)

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R and D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions

  9. STAR Upgrade Plan for the Coming Decade

    Science.gov (United States)

    Huang, Huan Zhong

    2013-05-01

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R&D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions.

  10. STAR Upgrade Plan for the Coming Decade

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Huan Zhong

    2013-05-02

    The STAR Collaboration will complete the Heavy Flavor Tracker (HFT) and the Muon Telescope Detector (MTD) upgrades by 2014. STAR has also embarked on an upgrade plan to extend the capabilities for measuring jets, electron/photon and leading particles in the forward rapidity region in the coming decade. Planned detector upgrades include tracking detectors for charged particles, electro-magnetic and hadronic calorimeters and particle identification detector in the forward direction. We will present physics motivations, status of detector R and D and design considerations for the forward measurements focusing on p + p/p + A and polarized p + p collisions.

  11. 次世代型スタートラッカの研究

    OpenAIRE

    Matsumoto, Shuichi; Suzuki, Hideto; Kawai, Hiroshi; 松本 秀一; 鈴木 秀人; 川井 洋志

    2006-01-01

    Scientific satellites have been utilizing first generation star trackers that have only star imaging function. Recent technological advances on computer enable second generation star trackers that have autonomous star identification and attitude estimation functions without any a priori information. Based on requirements of future satellite programs and technological trends of overseas, we have been studying 'Next Generation Star Tracker' which categorized in the second generation star tracke...

  12. Stars and Star Myths.

    Science.gov (United States)

    Eason, Oliver

    Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

  13. EU Climate Policy Tracker 2011. Main report

    Energy Technology Data Exchange (ETDEWEB)

    Hoehne, N.; Geurts, F.; Teckenburg, E.; Blok, K.; Becker, D. [Ecofys, Utrecht (Netherlands)

    2011-11-15

    Limiting the rise in the average global temperature to 2C has been the EU goal since 1996, and in December 2010 the UN recognised the need to consider a 1.5C limit. Avoiding overshooting these levels will require massive emissions reductions - in the order of 80-95% for industrialised countries, like those in the EU. The next ten years are crucial in establishing whether society will be able to make this transition, or whether temperature increase limits will be irreversibly missed. Last year, the European Union Climate Policy Tracker (EU CPT) investigated each member state's implementation of policy and legislation, and rated their progress towards a 2050 vision of deep decarbonisation using renewable energy. The uniquely developed rating scheme, modelled on appliance efficiency labels (A-G), gave an indication of how member states were doing compared to a 'low-carbon policy package'. The average score was an 'E', indicating that the level of effort needed to treble, to be on a pace to reach the 2050 vision. However, aggregating best practices across sectors and countries doubled the score - meaning that the tools are already at hand for major improvements across Europe. This report builds on last year's EU CPT by giving an update on action in member states, and an indicative trend in the rating, as well as adding a new section on EU policy. The addition of an EU section is appropriate, with the Commission having produced a roadmap on a low-carbon economy by 2050, a transport white paper, and with another roadmap for 2050 focused on energy anticipated by the end of 2011. This report seeks to answer the question of whether these and other related initiatives are sufficient to help Europe reach its low-carbon goals. When interpreting the results of this report, it is important to understand that the goal underlying the vision here is not the same as the one in the European Commission's 'low-carbon economy' roadmap

  14. Data Quality Monitoring for the CMS Silicon Tracker

    CERN Document Server

    Dutta, S; Mennea, Maria Santa; Zito, G

    2006-01-01

    The CMS silicon tracker, consisting of about 17,000 detector modules and divided into micro-strip and pixel sensors, will be the largest silicon tracker ever realized for high energy physics experiments. The detector performance will be monitored using applications based on the CMS Data Quality Monitoring\\,(DQM) framework and running on the High-Level Trigger Farm as well as local DAQ systems. The monitorable quantities of this large number of modules are divided into hierarchical structures reflecting the detector sections. In addition, they are organized into structures corresponding to the levels of data processing. The information produced are delivered to client applications according to their subscription requests. The client applications summarize and visualize the quantities received. We describe here the functionalities of the CMS tracker DQM applications and report preliminary performance tests.

  15. A fast hardware tracker for the ATLAS trigger system

    International Nuclear Information System (INIS)

    The Fast Tracker (FTK) processor is an approved ATLAS upgrade that will reconstruct tracks using the full silicon tracker at Level-1 rate (up to 100 KHz). FTK uses a completely parallel approach to read the silicon tracker information, execute the pattern matching and reconstruct the tracks. This approach, according to detailed simulation results, allows full tracking with nearly offline resolution within an execution time of 100μs. A central component of the system is the associative memories (AM); these special devices reduce the pattern matching combinatoric problem, providing identification of coarse resolution track candidates. The system consists of a pipeline of several components with the goal to organize and filter the data for the AM, then to reconstruct and filter the final tracks. This document presents an overview of the system and reports the status of the different elements of the system

  16. Latency and distortion of electromagnetic trackers for augmented reality systems

    CERN Document Server

    Himberg, Henry

    2014-01-01

    Augmented reality (AR) systems are often used to superimpose virtual objects or information on a scene to improve situational awareness. Delays in the display system or inaccurate registration of objects destroy the sense of immersion a user experiences when using AR systems. AC electromagnetic trackers are ideal for these applications when combined with head orientation prediction to compensate for display system delays. Unfortunately, these trackers do not perform well in environments that contain conductive or ferrous materials due to magnetic field distortion without expensive calibration

  17. Characterization of the Ecosole HCPV tracker and single module inverter

    Science.gov (United States)

    Carpanelli, Maurizio; Borelli, Gianni; Verdilio, Daniele; De Nardis, Davide; Migali, Fabrizio; Cancro, Carmine; Graditi, Giorgio

    2015-09-01

    BECAR, the Beghelli group's R&D company, is leading ECOSOLE (Elevated COncentration SOlar Energy), one of the largest European Demonstration projects in solar photovoltaic. ECOSOLE, started in 2012, is focused on the study, design, and realization of new HCPV generator made of high efficiency PV modules equipped with SoG (Silicone on Glass) fresnel lenses and III-V solar cells, and a low cost matched solar tracker with distributed inverters approach. The project also regards the study and demonstration of new high throughput methods for the industrial large scale productions, at very low manufacturing costs. This work reports the description of the characterization of the tracker and single module.

  18. Parallax error in the monocular head-mounted eye trackers

    DEFF Research Database (Denmark)

    Mardanbeigi, Diako; Witzner Hansen, Dan

    This paper investigates the parallax error, which is a common problem of many video-based monocular mobile gaze trackers. The parallax error is defined and described using the epipolar geometry in a stereo camera setup. The main parameters that change the error are introduced and it is shown how...... each parameter affects the error. The optimum distribution of the error (magnitude and direction) in the field of view varies for different applications. However, the results can be used for finding the optimum parameters that are needed for designing a head-mounted gaze tracker. It has been shown that...

  19. Online Monitoring for the Silicon Tracker of the LHCb Experiment

    CERN Document Server

    Chiapolini, N

    While the LHCb exp eriment acquires data, the detector and the data quality are continuously monitored. The rst part of this thesis describ es a package that was develop ed for managing monitoring pages. This package is a sub detector indep endent to ol originally develop ed for the online monitoring system of the Silicon Tracker. In the second half of this thesis, metho des to calculate the common mo de subtracted noise in the Silicon Tracker are compared. Dierent p ossible adjustments are evaluated and p ossible improvements presented.

  20. Design of a Solar Tracker System for PV Power Plants

    Directory of Open Access Journals (Sweden)

    Tiberiu Tudorache

    2010-04-01

    Full Text Available This paper deals with the design and execution of a solar tracker systemdedicated to the PV conversion panels. The proposed single axis solar tracker deviceensures the optimization of the conversion of solar energy into electricity by properlyorienting the PV panel in accordance with the real position of the sun. The operation of theexperimental model of the device is based on a DC motor intelligently controlled by adedicated drive unit that moves a mini PV panel according to the signals received from twosimple but efficient light sensors. The performance and characteristics of the solar trackerare experimentally analyzed.