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Sample records for range rf navigational

  1. Dual RF Astrodynamic GPS Orbital Navigator Satellite

    Science.gov (United States)

    Kanipe, David B.; Provence, Robert Steve; Straube, Timothy M.; Reed, Helen; Bishop, Robert; Lightsey, Glenn

    2009-01-01

    Dual RF Astrodynamic GPS Orbital Navigator Satellite (DRAGONSat) will demonstrate autonomous rendezvous and docking (ARD) in low Earth orbit (LEO) and gather flight data with a global positioning system (GPS) receiver strictly designed for space applications. ARD is the capability of two independent spacecraft to rendezvous in orbit and dock without crew intervention. DRAGONSat consists of two picosatellites (one built by the University of Texas and one built by Texas A and M University) and the Space Shuttle Payload Launcher (SSPL); this project will ultimately demonstrate ARD in LEO.

  2. Estimation of the RF Characteristics of Absorbing Materials in Broad RF Frequency Ranges

    CERN Document Server

    Fandos, R

    2008-01-01

    Absorbing materials are very often used in RF applications. Their electromagnetic characteristics (relative permittivity εr, loss tangent tan δ and conductivity σ) are needed in order to obtain a high-quality design of the absorbing pieces in the frequency range of interest. Unfortunately, suppliers often do not provide these quantities. A simple technique to determine them, based on the RF measurement of the disturbance created by the insertion of a piece of absorber in a waveguide, is presented in this note. Results for samples of two different materials, silicon carbide and aluminum nitride are presented. While the former has a negligible conductivity at the working frequencies, the conductivity of the latter has to be taken into account in order to obtain a meaningful estimation of εr and tan δ. The equations of Kramers & Kronig have been applied to the data as a cross check, confirming the results.

  3. Navigation in GPS Challenged Environments Based Upon Ranging Imagery

    Science.gov (United States)

    Markiel, J. N. Nikki

    The ability of living creatures to navigate their environment is one of the great mysteries of life. Humans, even from an early age, can acquire data about their surroundings, determine whether objects are movable or fixed, and identify open space, separate static and non-static objects, and move towards another location with minimal effort, in infinitesimal time spans. Over extended time periods humans can recall the location of objects and duplicate navigation tasks based purely on relative positioning of landmarks. Our ability to emulate this complex process in autonomous vehicles remains incomplete, despite significant research efforts over the past half century. Autonomous vehicles rely on a variety of electronic sensors to acquire data about their environment; the challenge is to transform that data into information supporting the objective of navigation. Historically, much of the sensor data was limited to the two dimensional (2D) instance; recent technological developments such as Laser Ranging and 3D Sonar are extending data collection to full three dimensional (3D) acquisition. The objective of this dissertation is the development of an algorithm to support the transformation of 3D ranging data into a navigation solution within unknown environments, and in the presence of dynamically moving objects. The algorithm reflects one of the very first attempts to leverage the 3D ranging technology for the purpose of autonomous navigation, and provides a system which enables the ability to complete the following objectives: • Separation of static and non-static elements in the environment. • Navigation based upon the range measurements of static elements. This research extends the body of knowledge in three primary topics. 1) The first is the development of a general method to identify n features in an initial data set from m features in a subsequent data set, given that both data sets are acquired via 3D ranging sensors. Accomplishing this objective

  4. A Single RF Emitter-Based Indoor Navigation Method for Autonomous Service Robots.

    Science.gov (United States)

    Sherwin, Tyrone; Easte, Mikala; Chen, Andrew Tzer-Yeu; Wang, Kevin I-Kai; Dai, Wenbin

    2018-02-14

    Location-aware services are one of the key elements of modern intelligent applications. Numerous real-world applications such as factory automation, indoor delivery, and even search and rescue scenarios require autonomous robots to have the ability to navigate in an unknown environment and reach mobile targets with minimal or no prior infrastructure deployment. This research investigates and proposes a novel approach of dynamic target localisation using a single RF emitter, which will be used as the basis of allowing autonomous robots to navigate towards and reach a target. Through the use of multiple directional antennae, Received Signal Strength (RSS) is compared to determine the most probable direction of the targeted emitter, which is combined with the distance estimates to improve the localisation performance. The accuracy of the position estimate is further improved using a particle filter to mitigate the fluctuating nature of real-time RSS data. Based on the direction information, a motion control algorithm is proposed, using Simultaneous Localisation and Mapping (SLAM) and A* path planning to enable navigation through unknown complex environments. A number of navigation scenarios were developed in the context of factory automation applications to demonstrate and evaluate the functionality and performance of the proposed system.

  5. Short-range wireless communication fundamentals of RF system design and application

    CERN Document Server

    Bensky, Alan

    2004-01-01

    The Complete "Tool Kit” for the Hottest Area in RF/Wireless Design!Short-range wireless-communications over distances of less than 100 meters-is the most rapidly growing segment of RF/wireless engineering. Alan Bensky is an internationally recognized expert in short-range wireless, and this new edition of his bestselling book is completely revised to cover the latest developments in this fast moving field.You'll find coverage of such cutting-edge topics as: architectural trends in RF/wireless integrated circuits compatibility and conflict issues between differen

  6. Efficient ranging-sensor navigation methods for indoor aircraft

    Science.gov (United States)

    Sobers, David Michael, Jr.

    Unmanned Aerial Vehicles (UAVs) are often used for reconnaissance, search and rescue, damage assessment, exploration, and other tasks that are dangerous or prohibitively difficult for humans to perform. Often, these tasks include traversing indoor environments where radio links are unreliable, hindering the use of remote pilot links or ground-based control, and effectively eliminating Global Positioning System (GPS) signals as a potential localization method. As a result, any vehicle capable of indoor flight must be able to stabilize itself and perform all guidance, navigation, and control (GNC) tasks without dependence on a radio link, which may be available only intermittently. Stability and control of rotorcraft UAVs is usually achieved by either a passive stability system, such as a Bell stabilizer bar, or by actively measuring body accelerations and angular rates with an onboard Inertial Measurement Unit (IMU) and using that data for feedback control. However, neither active nor passive attitude stabilization methods provide position control by themselves. Therefore, GNC methods must either be tolerant to position drift or have some means of estimating and controlling position, which requires an external reference in order to measure and correct errors in the position estimate. GPS signals are often the most convenient method for providing this external position reference. As a result, most UAVs utilize GPS for localization and to bound error on position drift. Unfortunately, the availability of GPS signals in unknown environments is not assured, especially during indoor operation. As a result, other sensors must be used to provide position information relative to the environment. This research covers a description of different ranging sensors and methods for incorporating them into the overall guidance, navigation, and control system. Various sensors are analyzed to determine their performance characteristics and suitability for indoor navigation, including

  7. High Dynamic Range RF Front End with Noise Cancellation and Linearization for WiMAX Receivers

    Directory of Open Access Journals (Sweden)

    J.-M. Wu

    2012-06-01

    Full Text Available This research deals with verification of the high dynamic range for a heterodyne radio frequency (RF front end. A 2.6 GHz RF front end is designed and implemented in a hybrid microwave integrated circuit (HMIC for worldwide interoperability for microwave access (WiMAX receivers. The heterodyne RF front end consists of a low-noise amplifier (LNA with noise cancellation, an RF bandpass filter (BPF, a downconverter with linearization, and an intermediate frequency (IF BPF. A noise canceling technique used in the low-noise amplifier eliminates a thermal noise and then reduces the noise figure (NF of the RF front end by 0.9 dB. Use of a downconverter with diode linearizer also compensates for gain compression, which increases the input-referred third-order intercept point (IIP3 of the RF front end by 4.3 dB. The proposed method substantially increases the spurious-free dynamic range (DRf of the RF front end by 3.5 dB.

  8. Calibration and control for range imaging in mobile robot navigation

    Energy Technology Data Exchange (ETDEWEB)

    Dorum, O.H. [Norges Tekniske Hoegskole, Trondheim (Norway). Div. of Computer Systems and Telematics; Hoover, A. [University of South Florida, Tampa, FL (United States). Dept. of Computer Science and Engineering; Jones, J.P. [Oak Ridge National Lab., TN (United States)

    1994-06-01

    This paper addresses some issues in the development of sensor-based systems for mobile robot navigation which use range imaging sensors as the primary source for geometric information about the environment. In particular, we describe a model of scanning laser range cameras which takes into account the properties of the mechanical system responsible for image formation and a calibration procedure which yields improved accuracy over previous models. In addition, we describe an algorithm which takes the limitations of these sensors into account in path planning and path execution. In particular, range imaging sensors are characterized by a limited field of view and a standoff distance -- a minimum distance nearer than which surfaces cannot be sensed. These limitations can be addressed by enriching the concept of configuration space to include information about what can be sensed from a given configuration, and using this information to guide path planning and path following.

  9. Dynamics of r.f. production of Stellarator plasmas in the ion cyclotron range of frequency

    Energy Technology Data Exchange (ETDEWEB)

    Moiseenko, V.E. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center; Lysoivan, A.I. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center; Kasilov, S.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center; Plyusnin, V.V. [Kharkov Inst. of Phys. and Tech. (Ukraine). Nat. Center

    1995-01-01

    The present study investigated numerically the process of r.f. production of plasma in the URAGAN-3M torsatron in the frequency range below the ion cyclotron frequency ({omega}<{omega}{sub ci}). The dynamics of r.f. plasma build-up at the stages of neutral gas burnout and plasma heating were studied using a zero-dimensional transport code, in which the plasma confinement law was determined by large helical device scaling. Two models for input r.f. power were used. In the first case, the r.f. power absorbed by the electrons was computed by a one-dimensional r.f. code solving Maxwell`s boundary problem equations. The mechanisms of electron heating through direct excitation of the slow wave (SW) by antennae as well as the conversion of fast wave (FW) into SW in the vicinity of Alfven resonance (scenario of Alfven heating) were taken into account in the computations. In the second case, an `ideal` model of r.f. power deposition onto the electrons as a linear function of plasma density was employed. A noticeable difference in plasma production dynamics computed for these two cases was found. Better agreement with experimental data obtained from the URAGAN-3M torsatron was found for the first case resulting from combination of the one-dimensional r.f. and zero-dimensional transport codes. ((orig.)).

  10. Wide-Range Adaptive RF-to-DC Power Converter for UHF RFIDs

    KAUST Repository

    Ouda, Mahmoud H.

    2016-07-27

    A wide-range, differential, cross-coupled rectifier is proposed with an extended dynamic range of input RF power that enables wireless powering from varying distances. The proposed architecture mitigates the reverse-leakage problem in conven- tional, cross-coupled rectifiers without degrading sensitivity. A prototype is designed for UHF RFID applications, and is imple- mented using 0.18 μ m CMOS technology. On-chip measurements demonstrate a sensitivity of − 18 dBm for 1 V output over a 100 k Ω load and a peak RF-to-DC power conversion efficiency of 65%. A conventional, fully cross-coupled rectifier is fabricated along- side for comparison and the proposed rectifier shows more than 2 × increase in dynamic range and a 25% boosting in output voltage than the conventional rectifier

  11. 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 a...

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

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcosm will use existing hardware and software from related programs to create a prototype Lunar Navigation Sensor (LNS) early in Phase II, such that most of the...

  13. Long-Range Navigation on Complex Networks using L\\'evy Random Walks

    OpenAIRE

    Riascos, A. P.; Mateos, José L.

    2012-01-01

    We introduce a strategy of navigation in undirected networks, including regular, random, and complex networks, that is inspired by L\\'evy random walks, generalizing previous navigation rules. We obtained exact expressions for the stationary probability distribution, the occupation probability, the mean first passage time, and the average time to reach a node on the network. We found that the long-range navigation using the L\\'evy random walk strategy, compared with the normal random walk stra...

  14. Ranging Consistency Based on Ranging-Compensated Temperature-Sensing Sensor for Inter-Satellite Link of Navigation Constellation.

    Science.gov (United States)

    Meng, Zhijun; Yang, Jun; Guo, Xiye; Zhou, Yongbin

    2017-06-13

    Global Navigation Satellite System performance can be significantly enhanced by introducing inter-satellite links (ISLs) in navigation constellation. The improvement in position, velocity, and time accuracy as well as the realization of autonomous functions requires ISL distance measurement data as the original input. To build a high-performance ISL, the ranging consistency among navigation satellites is an urgent problem to be solved. In this study, we focus on the variation in the ranging delay caused by the sensitivity of the ISL payload equipment to the ambient temperature in space and propose a simple and low-power temperature-sensing ranging compensation sensor suitable for onboard equipment. The experimental results show that, after the temperature-sensing ranging compensation of the ISL payload equipment, the ranging consistency becomes less than 0.2 ns when the temperature change is 90 °C.

  15. RFID Transponders' RF Emissions in Aircraft Communication and Navigation Radio Bands

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Koppen Sandra V.; Fersch, Mariatheresa S.

    2008-01-01

    Radiated emission data in aircraft communication and navigation bands are presented for several active radio frequency identification (RFID) tags. The individual tags are different in design, operation and transmitting frequencies. The process for measuring the tags emissions in a reverberation chamber is discussed. Measurement issues dealing with tag interrogation, low level measurement in the presence of strong transmissions, and tags low duty factors are discussed. The results show strong emissions, far exceeding aircraft emission limits and can be of potential interference risks.

  16. A highly sensitive RF-to-DC power converter with an extended dynamic range

    KAUST Repository

    Almansouri, Abdullah Saud Mohammed

    2017-10-24

    This paper proposes a highly sensitive RF-to-DC power converter with an extended dynamic range that is designed to operate at the medical band 433 MHz and simulated using 0.18 μm CMOS technology. Compared to the conventional fully cross-coupled rectifier, the proposed design offers 3.2× the dynamic range. It is also highly sensitive and requires −18 dBm of input power to produce a 1 V-output voltage when operating with a 100 kΩ load. Furthermore, the proposed design offers an open circuit sensitivity of −23.4 dBm and a peak power conversion efficiency of 67%.

  17. High-dynamic-range and high-capacity RF and microwave fiber optic links

    Science.gov (United States)

    Weiss, Frank

    2013-05-01

    Novel fiber optic transmitter control methodologies, high optical power and low RIN source lasers, high performance photodiodes and DWDM laser capability provide high dynamic range and high capacity transport for a wide range of sensing and communications applications. Measured component and system level test data demonstrates these performance improvements. Higher spur free dynamic range in excess of 110 dB·Hz2/3 over broad range of K-band frequencies is demonstrated, increasing the practical use of fiber as a transport method for high sensitivity applications. Multichannel DWDM operation provides simplified capacity expansion without compromising system performance, allowing arrayed photonic systems to be deployed. System characterization for a wide range of optical wavelengths and RF frequencies is provided to demonstrate these levels of performance in practical applications. Photonic component cost reductions combined with compact packaging further increase the ability of high performance fiber optic transport to address a wider range of applications, as the size, weight and performance barriers are eliminated. This paper provides a summary of the current state of the art of commercially available photonic components for high performance externally modulated analog optical links from a practical perspective.

  18. Long-range navigation on complex networks using Lévy random walks

    Science.gov (United States)

    Riascos, A. P.; Mateos, José L.

    2012-11-01

    We introduce a strategy of navigation in undirected networks, including regular, random, and complex networks, that is inspired by Lévy random walks, generalizing previous navigation rules. We obtained exact expressions for the stationary probability distribution, the occupation probability, the mean first passage time, and the average time to reach a node on the network. We found that the long-range navigation using the Lévy random walk strategy, compared with the normal random walk strategy, is more efficient at reducing the time to cover the network. The dynamical effect of using the Lévy walk strategy is to transform a large-world network into a small world. Our exact results provide a general framework that connects two important fields: Lévy navigation strategies and dynamics on complex networks.

  19. Phase Compensation Sensor for Ranging Consistency in Inter-Satellite Links of Navigation Constellation.

    Science.gov (United States)

    Meng, Zhijun; Yang, Jun; Guo, Xiye; Hu, Mei

    2017-02-24

    Theperformanceoftheglobalnavigationsatellitesystem(GNSS)canbeenhancedsignificantly by introducing the inter-satellite links (ISL) of a navigation constellation. In particular, the improvement of the position, velocity, and time accuracy, and the realization of autonomous functions require the ISL distance measurement data as the original input. For building a high-performance ISL, the ranging consistency between navigation satellites becomes a crucial problem to be addressed. Considering the frequency aging drift and the relativistic effect of the navigation satellite, the frequency and phase adjustment (FPA) instructions for the 10.23 MHz must be injected from the ground station to ensure the time synchronization of the navigation constellation. Moreover, the uncertainty of the initial phase each time the onboard clock equipment boots also results in a pseudo-range offset. In this Ref., we focus on the influence of the frequency and phase characteristics of the onboard clock equipment on the ranging consistency of the ISL and propose a phase compensation sensor design method for the phase offset. The simulation and experimental results show that the proposed method not only realized a phase compensation for the pseudo-range jitter, but, when the 1 PPS (1 pulse per second) falls in the 10.23 MHz skip area, also overcomes the problem of compensating the ambiguous phase by directly tracking the 10.23 MHz to ensure consistency in the ranging.

  20. Navigation.

    Science.gov (United States)

    Wiltschko, Roswitha

    2017-07-01

    Experiments with migrating birds displaced during autumn migration outside their normal migration corridor reveal two different navigational strategies: adult migrants compensate for the displacement, and head towards their traditional wintering areas, whereas young first-time migrants continue in their migratory direction. Young birds are guided to their still unknown goal by a genetically coded migration program that indicates duration and direction(s) of the migratory flight by controlling the amount of migratory restlessness and the compass course(s) with respect to the geomagnetic field and celestial rotation. Adult migrants that have already wintered and are familiar with the goal area approach the goal by true navigation, specifically heading towards it and changing their course correspondingly after displacement. During their first journey, young birds experience the distribution of potential navigational factors en route and in their winter home, which allows them to truly navigate on their next migrations. The navigational factors used appear to include magnetic intensity as a component in their multi-modal navigational 'map'; olfactory input is also involved, even if it is not yet entirely clear in what way. The mechanisms of migratory birds for true navigation over long distances appear to be in principle similar to those discussed for by homing pigeons.

  1. Indoor pedestrian navigation using foot-mounted IMU and portable ultrasound range sensors.

    Science.gov (United States)

    Girard, Gabriel; Côté, Stéphane; Zlatanova, Sisi; Barette, Yannick; St-Pierre, Johanne; van Oosterom, Peter

    2011-01-01

    Many solutions have been proposed for indoor pedestrian navigation. Some rely on pre-installed sensor networks, which offer good accuracy but are limited to areas that have been prepared for that purpose, thus requiring an expensive and possibly time-consuming process. Such methods are therefore inappropriate for navigation in emergency situations since the power supply may be disturbed. Other types of solutions track the user without requiring a prepared environment. However, they may have low accuracy. Offline tracking has been proposed to increase accuracy, however this prevents users from knowing their position in real time. This paper describes a real time indoor navigation system that does not require prepared building environments and provides tracking accuracy superior to previously described tracking methods. The system uses a combination of four techniques: foot-mounted IMU (Inertial Motion Unit), ultrasonic ranging, particle filtering and model-based navigation. The very purpose of the project is to combine these four well-known techniques in a novel way to provide better indoor tracking results for pedestrians.

  2. EnEx-RANGE - Robust autonomous Acoustic Navigation in Glacial icE

    Science.gov (United States)

    Heinen, Dirk; Eliseev, Dmitry; Henke, Christoph; Jeschke, Sabina; Linder, Peter; Reuter, Sebastian; Schönitz, Sebastian; Scholz, Franziska; Weinstock, Lars Steffen; Wickmann, Stefan; Wiebusch, Christopher; Zierke, Simon

    2017-03-01

    Within the Enceladus Explorer Initiative of the DLR Space Administration navigation technologies for a future space mission are in development. Those technologies are the basis for the search for extraterrestrial life on the Saturn moon Enceladus. An autonomous melting probe, the EnEx probe, aims to extract a liquid sample from a water reservoir below the icy crust. A first EnEx probe was developed and demonstrated in a terrestrial scenario at the Bloodfalls, Taylor Glacier, Antarctica in November 2014. To enable navigation in glacier ice two acoustic systems were integrated into the probe in addition to conventional navigation technologies. The first acoustic system determines the position of the probe during the run based on propagation times of acoustic signals from emitters at reference positions at the glacier surface to receivers in the probe. The second system provides information about the forefield of the probe. It is based on sonographic principles with phased array technology integrated in the probe's melting head. Information about obstacles or sampling regions in the probe's forefield can be acquired. The development of both systems is now continued in the project EnEx-RANGE. The emitters of the localization system are replaced by a network of intelligent acoustic enabled melting probes. These localize each other by means of acoustic signals and create the reference system for the EnEx probe. This presentation includes the discussion of the intelligent acoustic network, the acoustic navigation systems of the EnEx probe and results of terrestrial tests.

  3. Single-Chip Fully Integrated Direct-Modulation CMOS RF Transmitters for Short-Range Wireless Applications

    Directory of Open Access Journals (Sweden)

    M. Jamal Deen

    2013-08-01

    Full Text Available Ultra-low power radio frequency (RF transceivers used in short-range application such as wireless sensor networks (WSNs require efficient, reliable and fully integrated transmitter architectures with minimal building blocks. This paper presents the design, implementation and performance evaluation of single-chip, fully integrated 2.4 GHz and 433 MHz RF transmitters using direct-modulation power voltage-controlled oscillators (PVCOs in addition to a 2.0 GHz phase-locked loop (PLL based transmitter. All three RF transmitters have been fabricated in a standard mixed-signal CMOS 0.18 µm technology. Measurement results of the 2.4 GHz transmitter show an improvement in drain efficiency from 27% to 36%. The 2.4 GHz and 433 MHz transmitters deliver an output power of 8 dBm with a phase noise of −122 dBc/Hz at 1 MHz offset, while drawing 15.4 mA of current and an output power of 6.5 dBm with a phase noise of −120 dBc/Hz at 1 MHz offset, while drawing 20.8 mA of current from 1.5 V power supplies, respectively. The PLL transmitter delivers an output power of 9 mW with a locking range of 128 MHz and consumes 26 mA from 1.8 V power supply. The experimental results demonstrate that the RF transmitters can be efficiently used in low power WSN applications.

  4. A high dynamic range linear RF power detector with a preceding LNA

    Science.gov (United States)

    Yingbo, Dai; Kefeng, Han; Na, Yan; Xi, Tan

    2012-01-01

    A design of high dynamic range linear radio frequency power detector (PD), aimed for transmitter carrier leakage suppression is presented in this paper. Based on the logarithmic amplifier principle, this detector utilizes the successive detection method to achieve a high dynamic range in the radio frequency band. In order to increase sensitivity, a low noise amplifier (LNA) is placed in the front of this detector. DC coupling is adopted in this architecture to reduce parasitics and save area, but this will unavoidably cause DC offsets in the circuit which are detrimental to the dynamic range. So a DC offset cancelling (DCOC) technique is proposed to solve the problem. Finally, this detector was fabricated in the SMIC 0.13 μm CMOS process. The measured results show that it achieves a wide dynamic range of 50 dB/40 dB with log errors in ±1 dB at 900 MHz/2 GHz, while draws 16 mA from a 1.5 V power supply. The active chip area is 0.27 × 0.67 mm2.

  5. A Recommendation on SLR Ranging to Future Global Navigation Satellite Systems

    Science.gov (United States)

    Labrecque, J. L.; Miller, J. J.; Pearlman, M.

    2008-12-01

    The multi-agency US Geodetic Requirements Working Group has recommended that Satellite Laser Retro- reflectors be installed on GPS III satellites as a principal component of the Positioning, Navigation, and Timing mandate of the Global Positioning System. The Working Group, which includes NASA, NGA, NOAA, NRL, USGS, and the USNO, echoes the Global Geodetic Observing System recommendation that SLR retro- reflectors be installed on all GNSS satellites. It is further recommended that the retro-reflectors conform to and hopefully exceed the minimum standard of the International Laser Ranging Service for retro-reflector cross sections of 100 million square meters for the HEO GNSS satellites to insure sufficiently accurate ranging by the global network of satellite laser ranging systems. The objective of this recommendation is to contribute to the improvement in the International Terrestrial Reference Frame, and its derivative the WGS84 reference frame, through continuing improvements in the characterization of the GPS orbits and clocks. Another objective is to provide an independent means of assessing the interoperability and accuracy of the GNSS systems and regional augmentation systems. The ranging to GNSS-mounted retro-reflectors will constitute a significant new means of space-based collocation to constrain the tie between the GPS and SLR networks that constitute over 50% of the data from which the ITRF is derived. The recommendation for the installation of SLR retro-reflectors aboard future GPS satellites is one of a number of efforts aimed at improving the accuracy and stability of ITRF. These steps are being coordinated with and supportive of the efforts of the GGOS and its services such at the VLBI2010 initiative, developing a next generation geodetic network, near real-time GPS positioning and EOP determination, and numerous efforts in the improvement of geodetic algorithms for GPS, SLR, VLBI, DORIS, and the determination of the ITRF. If past is prologue, the

  6. Alpha- and theta-range cortical synchronization and corticomuscular coherence during joystick manipulation in a virtual navigation task.

    Science.gov (United States)

    Hori, Satoshi; Matsumoto, Jumpei; Hori, Etsuro; Kuwayama, Naoya; Ono, Taketoshi; Kuroda, Satoshi; Nishijo, Hisao

    2013-10-01

    Previous studies have reported that multiple brain regions are activated during spatial navigation, but it remains unclear how this activation is converted to motor commands for navigation. This study was aimed to investigate synchronization across different brain regions and between cortical areas and muscles during spatial navigation. This synchronization has been suggested to be essential for integrating activity in the multiple brain areas to support higher cognitive functions and for conversion of cortical activity to motor commands. In the present study, the subjects were required to sequentially trace ten checkpoints in a virtual town by manipulating a joystick and to perform this three times while electroencephalograms and electromyograms from the right arm were monitored. Time spent on the task in the third trial was significantly lesser than that in the first trial indicating an improvement in task performance. This repeated learning was associated with an increase in alpha power at the electrodes over the contralateral sensorimotor region and in theta power at the electrodes over the bilateral premotor and frontotemporal regions. Alpha- and theta-range corticocortical coherences between these regions and other brain areas were also increased in the third trial compared to the first trial. Furthermore, alpha- and theta-range corticomuscular coherence was significantly increased in the second and third trials compared to the first trial. These results suggest that alpha- and theta-range synchronous activity across multiple systems is essential for the integrated brain activity required in spatial navigation and for the conversion of this activity to motor commands.

  7. Indoor Pedestrian Navigation Using Foot-Mounted IMU and Portable Ultrasound Range Sensors

    NARCIS (Netherlands)

    Girard, G.; Cote, S.; Zlatanova, S.; Barette, Y.; St-Pierre, J.; Van Oosterom, P.J.M.

    2011-01-01

    Many solutions have been proposed for indoor pedestrian navigation. Some rely on pre-installed sensor networks, which offer good accuracy but are limited to areas that have been prepared for that purpose, thus requiring an expensive and possibly time-consuming process. Such methods are therefore

  8. Terrain Referenced Navigation Using SIFT Features in LiDAR Range-Based Data

    Science.gov (United States)

    2014-12-26

    and scales k within each octave, then finally subtracted to create DoG images D. . . . . . . . . . . 29 viii Figure Page 2.13 In this example a 2x2...Elevation Model DoG Difference of Gaussian ECEF Earth Centered Earth Fixed ENU East North Up GNSS Global Navigation Satellite Systems GPS Global...was inspired by human eye behaviour and can be broken up into two primary steps, keypoint detection and descriptor creation. The SIFT algorithm is an

  9. Experimentally altered navigational demands induce changes in the cortical forebrain of free-ranging northern pacific rattlesnakes (Crotalus o. oreganus).

    Science.gov (United States)

    Holding, Matthew L; Frazier, Julius A; Taylor, Emily N; Strand, Christine R

    2012-01-01

    The hippocampus of birds and mammals plays a crucial role in spatial memory and navigation. The hippocampus exhibits plasticity in adulthood in response to diverse environmental factors associated with spatial demands placed on an animal. The medial and dorsal cortices of the telencephalon of squamate reptiles have been implicated as functional homologues to the hippocampus. This study sought to experimentally manipulate the navigational demands placed on free-ranging northern Pacific rattlesnakes (Crotalus o. oreganus) to provide direct evidence of the relationship between spatial demands and neuroplasticity in the cortical telencephalon of the squamate brain. Adult male rattlesnakes were radio-tracked for 2 months, during which time 1 of 3 treatments was imposed weekly, namely 225-meter translocation in a random direction, 225-meter walk and release at that day's capture site (handling control) or undisturbed (control). Snakes were then sacrificed and the brains were removed and processed for histological analysis of cortical features. The activity range was larger in the translocated (Tr) group compared to the handled (Hd) and undisturbed control (Cn) groups when measured via 95% minimum convex polygon (MCP). At the 100% MCP level, Tr snakes had larger activity ranges than the Cn snakes only. The volume of the medial cortex (MC) was larger in the Tr group compared to the Cn group. The MC of Hd snakes was not significantly different from that of either of the other groups. No differences in dorsal cortex (DC) or lateral cortex volumes were detected among the groups. Numbers of 5-bromo-2'-deoxyuridine (BrdU)-labeled cells in the MC and DC 3 weeks after BrdU injection were not affected by treatment. This study establishes a causal relationship between navigational demands and greater MC volume in a free-ranging reptile. Copyright © 2012 S. Karger AG, Basel.

  10. The dielectric properties of human pineal gland tissue and RF absorption due to wireless communication devices in the frequency range 400-1850 MHz

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Gernot [Austrian Research Centers GmbH-ARC, ITM, A-2444 Seibersdorf (Austria); Ueberbacher, Richard [Austrian Research Centers GmbH-ARC, ITM, A-2444 Seibersdorf (Austria); Samaras, Theodoros [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Tschabitscher, Manfred [Center of Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna (Austria); Mazal, Peter R [Department of Clinical Pathology, Medical University Vienna, A-1090 Vienna (Austria)

    2007-09-07

    In order to enable a detailed analysis of radio frequency (RF) absorption in the human pineal gland, the dielectric properties of a sample of 20 freshly removed pineal glands were measured less than 20 h after death. Furthermore, a corresponding high resolution numerical model of the brain region surrounding the pineal gland was developed, based on a real human tissue sample. After inserting this model into a commercially available numerical head model, FDTD-based computations for exposure scenarios with generic models of handheld devices operated close to the head in the frequency range 400-1850 MHz were carried out. For typical output power values of real handheld mobile communication devices, the obtained results showed only very small amounts of absorbed RF power in the pineal gland when compared to SAR limits according to international safety standards. The highest absorption was found for the 400 MHz irradiation. In this case the RF power absorbed inside the pineal gland (organ mass 96 mg) was as low as 11 {mu}W, when considering a device of 500 mW output power operated close to the ear. For typical mobile phone frequencies (900 MHz and 1850 MHz) and output power values (250 mW and 125 mW) the corresponding values of absorbed RF power in the pineal gland were found to be lower by a factor of 4.2 and 36, respectively. These results indicate that temperature-related biologically relevant effects on the pineal gland induced by the RF emissions of typical handheld mobile communication devices are unlikely.

  11. Lidar multi-range integrated Dewar assembly (IDA) for active-optical vision navigation sensor

    Science.gov (United States)

    Mayner, Philip; Clemet, Ed; Asbrock, Jim; Chen, Isabel; Getty, Jonathan; Malone, Neil; De Loo, John; Giroux, Mark

    2013-09-01

    A multi-range focal plane was developed and delivered by Raytheon Vision Systems for a docking system that was demonstrated on STS-134. This required state of the art focal plane and electronics synchronization to capture nanosecond length laser pulses to determine ranges with an accuracy of less than 1 inch.

  12. On achieving sufficient dual station range accuracy for deep space navigation at zero declination

    Science.gov (United States)

    Siegel, H. L.; Christensen, C. S.; Green, D. W.; Winn, F. B.

    1977-01-01

    Since the Voyager Mission will encounter Saturn at a time when the planet will be nearly in the earth's equatorial plane, earth-based orbit determination will be more difficult than usual because of the so-called zero-declination singularity associated with conventional radiometric observations. Simulation studies show that in order to meet the required delivery accuracy at Saturn, a relative range measurement between the Goldstone and Canberra Deep Space Stations must be accurate to 4.5 times the square root of two meters. Topics discussed include the nature of error sources, the methodology and technology required for calibration, the verification process concerning the nearly simultaneous range capability, a description of the ranging system, and tracking strategy.

  13. Constructing maps for mobile robot navigation based on ultrasonic range data.

    Science.gov (United States)

    Kurz, A

    1996-01-01

    This paper introduces an approach to generating environmental maps based on ultrasonic range data. By means of a learning classifier ultrasonic range data are condensed yielding abstract concepts which enable a mobile robot to discern situations. As a consequence the free-space can be partitioned into situation areas which are defined as regions wherein a specific situation can be recognized. Using dead-reckoning such situation areas can be attached to graph nodes generating a map of the free-space in the form of a graph representation. How the extended Kalman filter algorithm can be applied in this context to compensate the dead-reckoning drift is also discussed.

  14. Laser range finder model for autonomous navigation of a robot in a maize field using a particle filter

    NARCIS (Netherlands)

    Hiremath, S.A.; Heijden, van der G.W.A.M.; Evert, van F.K.; Stein, A.; Braak, ter C.J.F.

    2014-01-01

    Autonomous navigation of robots in an agricultural environment is a difficult task due to the inherent uncertainty in the environment. Many existing agricultural robots use computer vision and other sensors to supplement Global Positioning System (GPS) data when navigating. Vision based methods are

  15. Optimetrics for Precise Navigation

    Science.gov (United States)

    Yang, Guangning; Heckler, Gregory; Gramling, Cheryl

    2017-01-01

    Optimetrics for Precise Navigation will be implemented on existing optical communication links. The ranging and Doppler measurements are conducted over communication data frame and clock. The measurement accuracy is two orders of magnitude better than TDRSS. It also has other advantages of: The high optical carrier frequency enables: (1) Immunity from ionosphere and interplanetary Plasma noise floor, which is a performance limitation for RF tracking; and (2) High antenna gain reduces terminal size and volume, enables high precision tracking in Cubesat, and in deep space smallsat. High Optical Pointing Precision provides: (a) spacecraft orientation, (b) Minimal additional hardware to implement Precise Optimetrics over optical comm link; and (c) Continuous optical carrier phase measurement will enable the system presented here to accept future optical frequency standard with much higher clock accuracy.

  16. RF MEMS

    Indian Academy of Sciences (India)

    bridges the gap in the signal line, thereby connecting the two ports of the device. This repre- ..... Packaging related parasitics tend to degrade RF performance, limiting the usage of the devices to much lower ... bonds are known to cause higher losses due to impedance mismatch with the 50 transmission lines. The RF bond ...

  17. RF Measurement Concepts

    CERN Document Server

    Caspers, F

    2014-01-01

    For the characterization of components, systems and signals in the radiofrequency (RF) and microwave ranges, several dedicated instruments are in use. In this article the fundamentals of the RF signal techniques are discussed. The key element in these front ends is the Schottky diode which can be used either as a RF mixer or as a single sampler. The spectrum analyser has become an absolutely indispensable tool for RF signal analysis. Here the front end is the RF mixer as the RF section of modern spectrum analyses has a ra ther complex architecture. The reasons for this complexity and certain working principles as well as limitations are discussed. In addition, an overview of the development of scalar and vector signal analysers is given. For the determination of the noise temperature of a one-port and the noise figure of a two-port, basic concepts and relations are shown as well as a brief discussion of commonly used noise-measurement techniques. In a further part of this article the operating principles of n...

  18. Navigating life.

    Science.gov (United States)

    Cohen, Neal J

    2015-06-01

    The discoveries of "place cells" in the hippocampus and "grid cells" in the entorhinal cortex are landmark achievements in relating behavior to neural activity, permitting analysis of a powerful system for spatial representation in the brain. The contributions of this work include not only the empirical findings but also the approach this work pioneered of examining neural activity in complex behaviors with real ecological validity in freely moving animals, and of attempting to place the findings in the larger context of how the neural representations of space are used in service of real-world behavior, namely what the Nobel committee described as permitting us to "navigate our way through a complex environment." These discoveries and approaches have had far-ranging impact on and implications for work in human cognitive neuroscience, where we see (1) confirmation in humans that the hippocampus and overlying MTL cortex are critically engaged in supporting a relational representation of space, and that it can be used for flexible spatial navigation and (2) evidence that these regions are also critically involved in aspects of relational memory not limited to space, and in the flexible use of hippocampal memory extending beyond spatial navigation. Recent work, using tasks that emphasize the requirement for the active use of memory in online processing, just as spatial navigation has long placed such a requirement on rodents, suggests that the hippocampus and related MTL cortex can support the navigating of environments even more complex than what is needed in spatial navigation. It allows us to use memory in guiding upcoming actions and choices to act optimally in and on the world, permitting us to navigate life in all its beautiful complexity. © 2015 Wiley Periodicals, Inc.

  19. RF transformer

    Science.gov (United States)

    Smith, James L.; Helenberg, Harold W.; Kilsdonk, Dennis J.

    1979-01-01

    There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.

  20. The invisible cues that guide king penguin chicks home: use of magnetic and acoustic cues during orientation and short-range navigation.

    Science.gov (United States)

    Nesterova, Anna P; Chiffard, Jules; Couchoux, Charline; Bonadonna, Francesco

    2013-04-15

    King penguins (Aptenodytes patagonicus) live in large and densely populated colonies, where navigation can be challenging because of the presence of many conspecifics that could obstruct locally available cues. Our previous experiments demonstrated that visual cues were important but not essential for king penguin chicks' homing. The main objective of this study was to investigate the importance of non-visual cues, such as magnetic and acoustic cues, for chicks' orientation and short-range navigation. In a series of experiments, the chicks were individually displaced from the colony to an experimental arena where they were released under different conditions. In the magnetic experiments, a strong magnet was attached to the chicks' heads. Trials were conducted in daylight and at night to test the relative importance of visual and magnetic cues. Our results showed that when the geomagnetic field around the chicks was modified, their orientation in the arena and the overall ability to home was not affected. In a low sound experiment we limited the acoustic cues available to the chicks by putting ear pads over their ears, and in a loud sound experiment we provided additional acoustic cues by broadcasting colony sounds on the opposite side of the arena to the real colony. In the low sound experiment, the behavior of the chicks was not affected by the limited sound input. In the loud sound experiment, the chicks reacted strongly to the colony sound. These results suggest that king penguin chicks may use the sound of the colony while orienting towards their home.

  1. Application of the Two-Step Filter to Process Ranging Measurements for Relative Navigation in an Elliptical Orbit

    Science.gov (United States)

    Garrison, James L.; Axelrad, Penina

    1997-01-01

    This estimator breaks a nonlinear estimation problem into a set of over determined 'first step' states which are linear in the observations and 'second step' states which are ultimately the states of interest. Linear estimation methods are applied to filter the observations and produce the optimal first step state estimate. The 'second step' states are obtained through iterative nonlinear parameter estimation considering the first step states as observations. It has been shown that this process exactly minimizes the least squares cost function for static problems and provides a better solution than the iterated extended Kalman filter (EKF) for dynamic problems. The two step filter is applied in this paper to process range and range rate measurements between the two spacecraft. Details of the application of the two step estimator to this problem will be given, highlighting the use of a test for ill-conditioned covariance estimates that can result from the first order covariance propagation. A comparison will be made between the performance of the two step filter and the IEKF.

  2. Development of a Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

    Science.gov (United States)

    Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

    2007-01-01

    The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and. control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for inter-spacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of medium, moving platforms, and radiated power. The Path Emulator for RF Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

  3. Recycler barrier RF buckets

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab

    2011-03-01

    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  4. Radiation-Hardening of Best-in-Class SiGe Mixed-Signal and RF Electronics for Ultra-Wide Temperature Range Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative, reliable, low-power, and low-noise electronics that can operate over a wide temperature range and high radiation are critical for future NASA missions....

  5. Rf Station For Ion Beam Staking In Hirfl-csr

    CERN Document Server

    Arbuzov, V S; Bushuev, A A; Dranichnikov, A N; Gorniker, E I; Kendjebulatov, E K; Kondakov, A A; Kondaurov, M; Kruchkov, Ya G; Krutikhin, S A; Kurkin, G Ya; Mironenko, L A; Motygin, S V; Osipov, V N; Petrov, V M; Pilan, Andrey M; Popov, A M; Rashenko, V V; Selivanov, A N; Shteinke, A R; Vajenin, N F

    2004-01-01

    BINP has developed and produced the RF station for Institute of Modern Physics (IMP), Lanzhou, China, for multipurpose accelerator complex with electron cooling. The RF station will be used for accumulation of ion beams in the main ring of the system. It was successfully tested in IMP and installed into the main accelerator ring of the complex. The RF station includes accelerating RF cavity and RF power generator with power supplies. The station works within frequency range 6.0 - 14.0 MHz, maximum voltage across the accelerating gap of the RF cavity - 20 kV. In the RF cavity the 200 VNP ferrite is utilized. A residual gas pressure in vacuum chamber does not exceed 2,5E-11 mbar. Maximum output power of the RF generator 25 kW. The data acquisition and control of the RF station is based on COMPACT - PCI bus and provides all functions of monitoring and control.

  6. Additive manufacturing of RF absorbers

    Science.gov (United States)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  7. Ultraspectral: hyperspectral and rf features registered by IFSAR

    Science.gov (United States)

    Szu, Harold H.; Hsu, Charles C.

    2001-03-01

    Hyperspectral remote sensing by air platforms can passively generate over two hundred channels of images of terabyte data the ground surface reflectance/eminence simultaneously, with wavelength ranging from 0.4 to 2.5 micrometers and to include a full infrared spectrum. We have extended the hyperspectral to include RF spectral for both the foliage penetration (from L band 1 GHz to UHF band 0.5 GHz,) using the polarization RF features and the terrain location ID for automatic navigation registration. These generalizations are possible because we have based our design of the foliage penetration (FOPEN) Interferometric Synthetic Aperture Radar (IFSAR) on all digital transceiver array and Field Programmable Gate Arrays (FPGA). We are able to do that, since we have leveraged the ONR 100 dB Digital Array Radar (DAR) for shipboard volume search radar (VSR) using the matured & rugged GaAs cellular phone technology. We study whether the high dynamic range DAR VSR approach can overcome the long baseline terran curvature (that might otherwise not be suited for the FOLPEN low frequency IFSAR). We show the standard deviation of the phase digital resolution better then 1o might overcome the terrain curvature due to low frequency, and long time integration. The applications of this technology include environmental monitoring and mineral exploration and mining, communication and Aided Target Recognition (ATR). The hyperspectral imagery takes the advantage of more unique spectral signature in terms of the massively parallel artificial neural network computation using the unsupervised learning Independent Component Analyses (ICA) algorithm introduced to the Landsat by Szu. The supervised classification is based on the library of spectral signals of known object material characteristics using various constrained versions of the orthogonal subspace projections (OSP) by. In this paper, we combine both the supervised OSP and the unsupervised ICA hyperspectral imaging algorithms. Then

  8. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  9. Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

    Science.gov (United States)

    Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

    2007-01-01

    The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

  10. A 0.8-3 GHz RF-VGA with 35 dB dynamic range in 0.13 μm CMOS

    Science.gov (United States)

    Xi, Qin; Xingli, Huang; Yajie, Qin; Zhiliang, Hong

    2012-01-01

    A wideband variable gain amplifier (VGA) implemented in 0.13 μm CMOS technology is presented. To optimize noise performance, an active feedback amplifier with 15 dB fixed gain is put in the front, followed by modified Cherry—Hooper amplifiers in cascade providing variable gain, which adopt dual loop feedback for bandwidth extension. Negative capacitive neutralization and capacitive source degeneration are employed for Miller effect compensation and DC offset cancellation, respectively. Measurement results show that the proposed VGA achieves a 35 dB gain tuning range with an upper 3-dB bandwidth larger than 3 GHz and the input 1 dB compression point of -29 dBm at the lowest gain state, while the minimum noise figure is 9 dB at the highest gain state. The core VGA (without test buffer) consumes 32 mW from 1.2 V power supply and occupies 0.48 mm2 area.

  11. Magnetoplasmonic RF mixing and nonlinear frequency generation

    Energy Technology Data Exchange (ETDEWEB)

    Firby, C. J., E-mail: firby@ualberta.ca; Elezzabi, A. Y. [Ultrafast Optics and Nanophotonics Laboratory, Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada)

    2016-07-04

    We present the design of a magnetoplasmonic Mach-Zehnder interferometer (MZI) modulator facilitating radio-frequency (RF) mixing and nonlinear frequency generation. This is achieved by forming the MZI arms from long-range dielectric-loaded plasmonic waveguides containing bismuth-substituted yttrium iron garnet (Bi:YIG). The magnetization of the Bi:YIG can be driven in the nonlinear regime by RF magnetic fields produced around adjacent transmission lines. Correspondingly, the nonlinear temporal dynamics of the transverse magnetization component are mapped onto the nonreciprocal phase shift in the MZI arms, and onto the output optical intensity signal. We show that this tunable mechanism can generate harmonics, frequency splitting, and frequency down-conversion with a single RF excitation, as well as RF mixing when driven by two RF signals. This magnetoplasmonic component can reduce the number of electrical sources required to generate distinct optical modulation frequencies and is anticipated to satisfy important applications in integrated optics.

  12. Rf Feedback free electron laser

    Science.gov (United States)

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1981-01-01

    A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  13. RF feedback for KEKB

    Energy Technology Data Exchange (ETDEWEB)

    Ezura, Eizi; Yoshimoto, Shin-ichi; Akai, Kazunori [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    This paper describes the present status of the RF feedback development for the KEK B-Factory (KEKB). A preliminary experiment concerning the RF feedback using a parallel comb-filter was performed through a choke-mode cavity and a klystron. The RF feedback has been tested using the beam of the TRISTAN Main Ring, and has proved to be effective in damping the beam instability. (author)

  14. GBO RF Anechoic Chamber & Antenna Test Range

    Data.gov (United States)

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  15. Off the Beaten tracks: Exploring Three Aspects of Web Navigation

    NARCIS (Netherlands)

    Weinreich, H.; Obendorf, H.; Herder, E.; Mayer, M.; Edmonds, H.; Hawkey, K.; Kellar, M.; Turnbull, D.

    2006-01-01

    This paper presents results of a long-term client-side Web usage study, updating previous studies that range in age from five to ten years. We focus on three aspects of Web navigation: changes in the distribution of navigation actions, speed of navigation and within-page navigation. “Navigation

  16. Prototype LHC RF cavity

    CERN Multimedia

    A radiofrequency (RF) cavity is a metallic chamber that contains an electromagnetic field. Its primary purpose is to accelerate charged particles. RF cavities can be structured like beads on a string, where the beads are the cavities and the string is the beam pipe of a particle accelerator, through which particles travel in a vacuum.

  17. Microfluidic stretchable RF electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2010-12-07

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  18. Microwave RF antennas and circuits nonlinearity applications in engineering

    CERN Document Server

    Aluf, Ofer

    2017-01-01

    This book describes a new concept for analyzing RF/microwave circuits, which includes RF/microwave antennas. The book is unique in its emphasis on practical and innovative microwave RF engineering applications. The analysis is based on nonlinear dynamics and chaos models and shows comprehensive benefits and results. All conceptual RF microwave circuits and antennas are innovative and can be broadly implemented in engineering applications. Given the dynamics of RF microwave circuits and antennas, they are suitable for use in a broad range of applications. The book presents analytical methods for microwave RF antennas and circuit analysis, concrete examples, and geometric examples. The analysis is developed systematically, starting with basic differential equations and their bifurcations, and subsequently moving on to fixed point analysis, limit cycles and their bifurcations. Engineering applications include microwave RF circuits and antennas in a variety of topological structures, RFID ICs and antennas, micros...

  19. Reconfigurable RF Filters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Micro proposes to build upon our existing space microelectronics and hardening technologies and products, to research and develop a novel rad hard/tolerant RF...

  20. Celestial Navigation

    Science.gov (United States)

    Rosenkrantz, Kurt

    2005-01-01

    In the unit described in this article, students discover the main principles of navigation, build tools to observe celestial bodies, and apply their new skills to finding their position on Earth. Along the way students see how science, mathematics, technology, and history are intertwined.

  1. The role of the transverse acetabular ligament for acetabular component orientation in total hip replacement: an analysis of acetabular component position and range of movement using navigation software

    National Research Council Canada - National Science Library

    Kalteis, T; Sendtner, E; Beverland, D; Archbold, P A; Hube, R; Schuster, T; Renkawitz, T; Grifka, J

    2011-01-01

    .... In order to assess the influence of alignment on impingement, the range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard acetabular component position (abduction 45°/anteversion 15...

  2. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  3. Remote RF Battery Charging

    NARCIS (Netherlands)

    Visser, H.J.; Pop, V.; Op het Veld, J.H.G.; Vullers, R.J.M.

    2011-01-01

    The design of a remote RF battery charger is discussed through the analysis and design of the subsystems of a rectenna (rectifying antenna): antenna, rectifying circuit and loaded DC-to-DC voltage (buck-boost) converter. Optimum system power generation performance is obtained by adopting a system

  4. AC/RF Superconductivity

    CERN Document Server

    Ciovati, G.

    2014-07-17

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  5. AC/RF Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [JLAB

    2015-02-01

    This contribution provides a brief introduction to AC/RF superconductivity, with an emphasis on application to accelerators. The topics covered include the surface impedance of normal conductors and superconductors, the residual resistance, the field dependence of the surface resistance, and the superheating field.

  6. Time-shaped RF brazing

    Science.gov (United States)

    Stein, J. A.; Vannasse, M. A.

    1980-01-01

    One RF generator is controlled from two independent work stations with aid of RF switch and simple control boxes. Brazing may be stopped manually or automatically by external brazing-temperature controller or timer in RF switch housing. Switch is air-operated with water-cooled contacts. If switch loses air pressure, generator stops transmitting power. Time-shared outlet increases utilization and productivity of costly RF generator.

  7. RF MEMS theory, design, and technology

    CERN Document Server

    Rebeiz, Gabriel M

    2003-01-01

    Ultrasmall Radio Frequency and Micro-wave Microelectromechanical systems (RF MEMs), such as switches, varactors, and phase shifters, exhibit nearly zero power consumption or loss. For this reason, they are being developed intensively by corporations worldwide for use in telecommunications equipment. This book acquaints readers with the basics of RF MEMs and describes how to design practical circuits and devices with them. The author, an acknowledged expert in the field, presents a range of real-world applications and shares many valuable tricks of the trade.

  8. Fundamentals of RF and microwave transistor amplifiers

    CERN Document Server

    Bahl, Inder J

    2009-01-01

    A Comprehensive and Up-to-Date Treatment of RF and Microwave Transistor Amplifiers This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help read

  9. Introduction to RF linear accelerators

    CERN Document Server

    Pichoff, N

    2006-01-01

    After a short introduction to applications of RF linacs and their advantages and drawbacks as opposed to circular accelerators, the model of RF resonant cavities and their excitation by RF sources or beam is introduced. Then beam dynamics notions, essential to linacs, such as transit-time factor, synchronism, r.m.s. properties, matching and mismatching in linear or nonlinear forces, are presented.

  10. Short Wave upwelling Radiative Flux (SWupRF) within NIR range for the selected greenhouse wavelength bands of O2, H2O, CO2 and CH4 by Argus 1000 along with GENSPECT line by line radiative transfer model

    CERN Document Server

    Siddiqui, Rehan; Salem, Naif Al; Quine, Brendan M

    2016-01-01

    This new study develops an algorithm for Short Wave upwelling Radiative Flux (SWupRF) for the spectral variations within near infrared (NIR) from 1100 to 1700 nm wavelength band based on remote sensing data set of Argus 1000 micro-spectrometer observations. We calculate the SWupRF by investigating the total radiative flux due to O2, H2O, CO2 and CH4 and also by the individual gas within the selected wavelength bands of interest. A GENSPECT synthetic line by line radiative transfer model is applied to perform radiative transfer simulations to calculate the radiative flux by varying surface albedo, mixing ratios of the selected greenhouse gases, surface temperature, solar sun and zenith angles with different latitude and longitude of the instrument. Finally, the SWupRFsyn estimated from GENSPECT was compared with SWupRFobs from Argus 1000 over a period of four years (2009 and 2013) covering all seasons. We calculate and compare both the synthetic and real measured observed data set. The synthetic model gives SW...

  11. Investigation of MIM Diodes for RF Applications

    KAUST Repository

    Khan, Adnan

    2015-05-01

    -crystalline structures and have orders of magnitude lower conductivities. Relatively lower resistances of the order of 1 k ohm with a sensitivity of 1.5 V-1 have been obtained through DC testing of these devices. Finally, RF characterization reveals that input impedances in the range of 300 Ω to 25 Ω can be achieved in the low GHz frequencies (from 1-10 GHz). From the rectification measurements at zero bias, a DC voltage of 4.7 mV has been obtained from an incoming RF signal of 0.4 W at 2.45 GHz, which indicates the suitability of these diodes for RF rectenna devices without providing any bias. It is believed that with further optimization, these devices can play an important role in RF energy harvesting without the need to bias them.

  12. Surgical Navigation

    DEFF Research Database (Denmark)

    Azarmehr, Iman; Stokbro, Kasper; Bell, R. Bryan

    2017-01-01

    body removal, respectively. The average technical system accuracy and intraoperative precision reported were less than 1 mm and 1 to 2 mm, respectively. In general, SN is reported to be a useful tool for surgical planning, execution, evaluation, and research. The largest numbers of studies and patients......Purpose: This systematic review investigates the most common indications, treatments, and outcomes of surgical navigation (SN) published from 2010 to 2015. The evolution of SN and its application in oral and maxillofacial surgery have rapidly developed over recent years, and therapeutic indications...... surgery, skull-base surgery, and foreign body removal were the areas of interests. Results: The search generated 13 articles dealing with traumatology; 5, 6, 2, and 0 studies were found that dealt with the topics of orthognathic surgery, cancer and reconstruction surgery, skull-base surgery, and foreign...

  13. RF Pulsed Heating

    Energy Technology Data Exchange (ETDEWEB)

    Pritzkau, David P.

    2002-01-03

    RF pulsed heating is a process by which a metal is heated from magnetic fields on its surface due to high-power pulsed RF. When the thermal stresses induced are larger than the elastic limit, microcracks and surface roughening will occur due to cyclic fatigue. Pulsed heating limits the maximum magnetic field on the surface and through it the maximum achievable accelerating gradient in a normal conducting accelerator structure. An experiment using circularly cylindrical cavities operating in the TE{sub 011} mode at a resonant frequency of 11.424 GHz is designed to study pulsed heating on OFE copper, a material commonly used in normal conducting accelerator structures. The high-power pulsed RF is supplied by an X-band klystron capable of outputting 50 MW, 1.5 {micro}s pulses. The test pieces of the cavity are designed to be removable to allow testing of different materials with different surface preparations. A diagnostic tool is developed to measure the temperature rise in the cavity utilizing the dynamic Q change of the resonant mode due to heating. The diagnostic consists of simultaneously exciting a TE{sub 012} mode to steady-state in the cavity at 18 GHz and measuring the change in reflected power as the cavity is heated from high-power pulsed RF. Two experimental runs were completed. One run was executed at a calculated temperature rise of 120 K for 56 x 10{sup 6} pulses. The second run was executed at a calculated temperature rise of 82 K for 86 x 10{sup 6} pulses. Scanning electron microscope pictures show extensive damage occurring in the region of maximum temperature rise on the surface of the test pieces.

  14. Microwave and RF engineering

    CERN Document Server

    Sorrentino, Roberto

    2010-01-01

    An essential text for both students and professionals, combining detailed theory with clear practical guidance This outstanding book explores a large spectrum of topics within microwave and radio frequency (RF) engineering, encompassing electromagnetic theory, microwave circuits and components. It provides thorough descriptions of the most common microwave test instruments and advises on semiconductor device modelling. With examples taken from the authors' own experience, this book also covers:network and signal theory;electronic technology with guided electromagnetic pr

  15. Performance Enhancements of Ranging Radio Aided Navigation

    Science.gov (United States)

    2009-03-01

    coordinate system. The system�s de�ning properties is that it is geocentric (center of mass is de�ned for the Earth). The orientation was initially...to the high radio standard deviation. In theory , the order in which measurements are incorporated into the �lter should not make any di¤erence. However

  16. Learning for Autonomous Navigation

    Science.gov (United States)

    Angelova, Anelia; Howard, Andrew; Matthies, Larry; Tang, Benyang; Turmon, Michael; Mjolsness, Eric

    2005-01-01

    Robotic ground vehicles for outdoor applications have achieved some remarkable successes, notably in autonomous highway following (Dickmanns, 1987), planetary exploration (1), and off-road navigation on Earth (1). Nevertheless, major challenges remain to enable reliable, high-speed, autonomous navigation in a wide variety of complex, off-road terrain. 3-D perception of terrain geometry with imaging range sensors is the mainstay of off-road driving systems. However, the stopping distance at high speed exceeds the effective lookahead distance of existing range sensors. Prospects for extending the range of 3-D sensors is strongly limited by sensor physics, eye safety of lasers, and related issues. Range sensor limitations also allow vehicles to enter large cul-de-sacs even at low speed, leading to long detours. Moreover, sensing only terrain geometry fails to reveal mechanical properties of terrain that are critical to assessing its traversability, such as potential for slippage, sinkage, and the degree of compliance of potential obstacles. Rovers in the Mars Exploration Rover (MER) mission have got stuck in sand dunes and experienced significant downhill slippage in the vicinity of large rock hazards. Earth-based off-road robots today have very limited ability to discriminate traversable vegetation from non-traversable vegetation or rough ground. It is impossible today to preprogram a system with knowledge of these properties for all types of terrain and weather conditions that might be encountered.

  17. SPS RF cavity

    CERN Multimedia

    1974-01-01

    The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. A power of up to 790 kW can be supplied to each giving a total accelerating voltage of about 8 MV. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities.

  18. Tools to aid navigation

    OpenAIRE

    Rovira, Cristòfol

    2001-01-01

    The problem of disorientation brought about by hypertext navigation can be solved by efficient tools to aid navigation such as summaries, indexes or navigation maps. In the article we analyse the main tools to aid navigation used in the Internet web, going futher into those which use knowledge representation to carry out their faction. We propose new ways of making navigation maps to favour access and understanding of information for hypertext environments in teaching-learning.

  19. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  20. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  1. SPS RF Cavity

    CERN Multimedia

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X, 7505074.

  2. LANSCE RF System Refurbishment

    CERN Document Server

    Rees, Daniel; Kwon, Sung-il; Lyles, John T M; Lynch, Michael; Prokop, Mark; Reass, William; Tallerico, Paul J

    2005-01-01

    The Los Alamos Neutron Science Center (LANSCE) is in the planning phase of a refurbishment project that will sustain reliable facility operations well into the next decade. The LANSCE accelerator was constructed in the late 1960s and early 1970s and is a national user facility that provides pulsed protons and spallation neutrons for defense and civilian research and applications. We will be replacing all the 201 MHz RF systems and a substantial fraction of the 805 MHz RF systems and high voltage systems. The current 44 LANSCE 805 MHz, 1.25 MW klystrons have an average in-service time in excess of 110,000 hours. All 44 must be in service to operate the accelerator. There are only 9 spares left. The klystrons receive their DC power from the power system originally installed in 1960. Although this power system has been extremely reliable, gas analysis of the insulating oil is indicating age related degradation that will need attention in the next few years. This paper will provide the design details of the new R...

  3. A Micromechanical RF Channelizer

    Science.gov (United States)

    Akgul, Mehmet

    The power consumption of a radio generally goes as the number and strength of the RF signals it must process. In particular, a radio receiver would consume much less power if the signal presented to its electronics contained only the desired signal in a tiny percent bandwidth frequency channel, rather than the typical mix of signals containing unwanted energy outside the desired channel. Unfortunately, a lack of filters capable of selecting single channel bandwidths at RF forces the front-ends of contemporary receivers to accept unwanted signals, and thus, to operate with sub-optimal efficiency. This dissertation focuses on the degree to which capacitive-gap transduced micromechanical resonators can achieve the aforementioned RF channel-selecting filters. It aims to first show theoretically that with appropriate scaling capacitive-gap transducers are strong enough to meet the needed coupling requirements; and second, to fully detail an architecture and design procedure needed to realize said filters. Finally, this dissertation provides an actual experimentally demonstrated RF channel-select filter designed using the developed procedures and confirming theoretical predictions. Specifically, this dissertation introduces four methods that make possible the design and fabrication of RF channel-select filters. The first of these introduces a small-signal equivalent circuit for parallel-plate capacitive-gap transduced micromechanical resonators that employs negative capacitance to model the dependence of resonance frequency on electrical stiffness in a way that facilitates the analysis of micromechanical circuits loaded with arbitrary electrical impedances. The new circuit model not only correctly predicts the dependence of electrical stiffness on the impedances loading the input and output electrodes of parallel-plate capacitive-gap transduced micromechanical device, but does so in a visually intuitive way that identifies current drive as most appropriate for

  4. RF Phase Scan for Beam Energy Measurement of KOMAC DTL

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hansung; Kwon, Hyeokjung; Kim, Seonggu; Lee, Seokgeun; Cho, Yongsub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The energy gain through the drift tube linac is a function of the synchronous phase, therefore, the output beam energy from DTL can be affected by the RF phase setting in low-level RF (LLRF) system. The DTL at Korea Multi-purpose Accelerator Complex (KOMAC) consists of 11 tanks and the RF phase setting in each tank should be matched for synchronous acceleration in successive tanks. That means a proper setting of RF phase in each DTL tank is critical for efficient and loss-free operation. The matching RF phase can be determined based on the output energy measurement from the DTL tank. The beam energy can be measured by several methods. For example, we can use a bending magnet to determine the beam energy because the higher momentum of beam means the less deflection angle in the fixed magnetic field. By measuring the range of proton beam through a material with known stopping power also can be utilized to determine the beam energy. We used a well-known time-of-flight method to determine the output beam energy from the DTL tank by measuring beam phase with a beam position monitor (BPM). Based on the energy measurement results, proper RF operating point could be obtained. We performed a RF phase scan to determine the output beam energy from KOMAC DTL by using a time-of-flight method and to set RF operating point precisely. The measured beam energy was compared with a beam dynamics simulation and showed a good agreement. RF phase setting is critical issue for the efficient operation of the proton accelerator, we have a plan to implement and integrate the RF phase measurement system into an accelerator control system for future need.

  5. Towards Safe Navigation by Formalizing Navigation Rules

    Directory of Open Access Journals (Sweden)

    Arne Kreutzmann

    2013-06-01

    Full Text Available One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs. Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio-temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can direcly be utilized by various bridge systems and that allows for software verification.

  6. RF and microwave engineering fundamentals of wireless communications

    CERN Document Server

    Gustrau, Frank

    2012-01-01

    This book provides a fundamental and practical introduction to radio frequency and microwave engineering and physical aspects of wireless communication In this book, the author addresses a wide range of radio-frequency and microwave topics with emphasis on physical aspects including EM and voltage waves, transmission lines, passive circuits, antennas, radio wave propagation. Up-to-date RF design tools like RF circuit simulation, EM simulation and computerized smith charts, are used in various examples to demonstrate how these methods can be applied effectively in RF engineering

  7. Accelerating Rf Station For Hirfl-csr, Lanzhou, China

    CERN Document Server

    Arbuzov, V S; Dranichnikov, A N; Gorniker, E I; Kondakov, A A; Kondaurov, M; Kruchkov, Ya G; Krutikhin, S A; Kurkin, G Ya; Mironenko, L A; Motygin, S V; Osipov, V N; Petrov, V M; Pilan, Andrey M; Popov, A M; Sedlyarov, I K; Selivanov, A N; Shteinke, A R; Vajenin, N F

    2004-01-01

    In accordance with the plan of cooperation with the Institute of Modern Physics (IMP), Lanzhou, China, the Budker Institute of Nuclear Physics (BINP), Novosibirsk, Russia has produced and supplied an accelerating RF station for the multipurpose Cooling Storage Ring system (CSR), which is being constructed at IMP. The RF station had been tested at IMP site and now is installed into the Main Ring of the facilities. The RF station operates in the frequency range of 0.25~1.7 MHz. Maximum accelerating voltage is 8 kV. The resonance frequency of the RF cavity is tuned in the whole frequency range by biasing of ferrites, which are used in the cavity. Ferrites of 600NN type were produced by a firm manufacture "Magneton", St. Petersburg. The pressure in the cavity vacuum chamber is lower, than 3·10-11

  8. RF breakdown by toroidal helicons

    Indian Academy of Sciences (India)

    Bounded whistlers are well-known for their efficient plasma production capabilities in thin cylindrical tubes. In this paper we shall present their radio frequency (RF) breakdown and discharge sustaining capabilities in toroidal systems. Pulsed RF power in the electronmagnetohydrodynamic (EMHD) frequency regime is fed to ...

  9. Circuit design for RF transceivers

    CERN Document Server

    Leenaerts, Domine; Vaucher, Cicero S

    2007-01-01

    Second edition of this successful 2001 RF Circuit Design book, has been updated, latest technology reviews have been added as well as several actual case studies. Due to the authors being active in industry as well as academia, this should prove to be an essential guide on RF Transceiver Design for students and engineers.

  10. Autonomous Navigation Above the GNSS Constellations and Beyond: GPS Navigation for the Magnetospheric Multiscale Mission and SEXTANT Pulsar Navigation Demonstration

    Science.gov (United States)

    Winternitz, Luke

    2017-01-01

    This talk will describe two first-of-their-kind technology demonstrations attached to ongoing NASA science missions, both of which aim to extend the range of autonomous spacecraft navigation far from the Earth. First, we will describe the onboard GPS navigation system for the Magnetospheric Multiscale (MMS) mission which is currently operating in elliptic orbits reaching nearly halfway to the Moon. The MMS navigation system is a key outgrowth of a larger effort at NASA Goddard Space Flight Center to advance high-altitude Global Navigation Satellite System (GNSS) navigation on multiple fronts, including developing Global Positioning System receivers and onboard navigation software, running simulation studies, and leading efforts to characterize and protect signals at high-altitude in the so-called GNSS Space-Service Volume (SSV). In the second part of the talk, we will describe the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) mission that aims to make the first in-space demonstration of X-ray pulsar navigation (XNAV). SEXTANT is attached to the NASA astrophysics mission Neutron-star Interior Composition ExploreR (NICER) whose International Space Station mounted X-ray telescope is investigating the fundamental physics of extremes in gravity, material density, and electromagnetic fields found in neutron stars, and whose instrument provides a nearly ideal navigation sensor for XNAV.

  11. Beam induced RF heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Bartmann, W; Baudrenghien, P; Berrig, O; Bracco, C; Bravin, E; Bregliozzi, G; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Garlasche, M; Gentini, L; Goddard, B; Grudiev, A; Henrist, B; Jones, R; Kononenko, O; Lanza, G; Lari, L; Mastoridis, T; Mertens, V; Métral, E; Mounet, N; Muller, J E; Nosych, A A; Nougaret, J L; Persichelli, S; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Salvachua, B; Sapinski, M; Schmidt, R; Shaposhnikova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wenninger, J; Wollmann, D; Zerlauth, M

    2012-01-01

    After the 2011 run, actions were put in place during the 2011/2012 winter stop to limit beam induced radio frequency (RF) heating of LHC components. However, some components could not be changed during this short stop and continued to represent a limitation throughout 2012. In addition, the stored beam intensity increased in 2012 and the temperature of certain components became critical. In this contribution, the beam induced heating limitations for 2012 and the expected beam induced heating limitations for the restart after the Long Shutdown 1 (LS1) will be compiled. The expected consequences of running with 25 ns or 50 ns bunch spacing will be detailed, as well as the consequences of running with shorter bunch length. Finally, actions on hardware or beam parameters to monitor and mitigate the impact of beam induced heating to LHC operation after LS1 will be discussed.

  12. Vulnerability of digitized platforms to modern rf electromagnetic weapons

    Science.gov (United States)

    Frater, Michael R.; Ryan, Michael J.

    2001-08-01

    Radio Frequency Directed Energy Weapons (RF DEW) have the potential to disrupt the operation of, or cause the failure of, a broad range of military electronic equipment. Over the past 30 years, there has been considerable effort in the development of these weapons. Recent reports suggest that a number of countries, including the USA and Russia, have fielded such weapons. This paper examines the potential performance of non-nuclear RF DEW.

  13. Autonomous navigation in a dynamic environment

    Science.gov (United States)

    Davies, Henry C.; Kayaalp, Ali E.; Moezzi, Saied

    1991-03-01

    Navigation of a mobile robot in the presence of dynamic obstacles requires fast data collection routemonitoring and route replanning. A method for route replanning in the presence of dynamic obstacles and an extendible autonomous vehicle navigation architecture based on this method is presented. At the center of our architecture is the Dynamic World Modeling subsystem which maintains an internal representation of the environment. It continuously assimilates time-varying stereo-based range data to build an accurate model of the world. The primary user of this information the Navigator subsystem plans a path for the vehicle to follow and insures that this path remains valid by computing detours when environmental changes block the planned path. A preliminary version of our autonomous navigation system utilizing a near real-time stereo range detection module is operational in our laboratory. It is used to navigate a Denning MIRV-2 mobile platform and executes in a distributed fashion on a network of Sun workstations.

  14. Co-doping effects of Mg and Be on properties of ZnMgBeGaO UV-range transparent conductive oxide films prepared by RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jang-Ho; Cuong, Hoang Ba [Photonic and Electronic Thin Film Laboratory, Department of Materials Science and Engineering, Chonnam National University, 300, Yong-bong dong, Gwangju 500-757 (Korea, Republic of); Jeong, Sang-Hun, E-mail: shjeong@kbsi.re.kr [Gwangju Center, Korea Basic Science Institute, 300, Yong-bong dong, Gwangju 500-757 (Korea, Republic of); Lee, Byung-Teak, E-mail: btlee@jnu.ac.kr [Photonic and Electronic Thin Film Laboratory, Department of Materials Science and Engineering, Chonnam National University, 300, Yong-bong dong, Gwangju 500-757 (Korea, Republic of)

    2014-12-05

    Highlights: • Zn{sub 0.96−x−y}Mg{sub x}Be{sub y}Ga{sub 0.04}O TCO films with wide band-gap were prepared by sputtering. • Controlling of band-gap and conductivity was tried by co-doping Mg and Be. • Maximum band-gap energy reached 3.88 eV at 5 at.% Mg and 10 at.% Be contents. • Post-growth annealing was performed in Ar + H{sub 2} ambient gas to improve conductivity. • The lowest resistivity was obtained from the annealed film at 400 °C. - Abstract: In this work, the Zn{sub 0.96-x−y}Mg{sub x}Be{sub y}Ga{sub 0.04}O films co-doped with different Mg and Be doping levels of 3 ∼10 at.% were prepared using an RF magnetron sputtering, and the correlation between the film properties and the doping levels was investigated. With an increase in Mg or Be doping level, the film crystal quality gradually deteriorated and the ZnO c-axis parameter was contracted or expanded due to the difference in ionic radii of Mg and Be ions, resulting in the shift of the ZnO (0 0 0 2) XRD peak position to lower 2θ or higher 2θ values and the broadening of the ZnO (0 0 0 2) XRD peak. All the grown films were highly transparent with a transmittance above 85% in the visible wavelength region and the band-gap widened from 3.74 eV to 3.88 eV at high doping level of 5 at.% Mg and 10 at.% Be, whereas the resistivity was degraded from 1.6 × 10{sup −3} Ω cm at low doping level to 1–4 × 10{sup −1} Ω cm at high doping level. In the Zn{sub 0.88}Mg{sub 0.05}Be{sub 0.03}Ga{sub 0.04}O film post growth annealed at 400 °C in Ar + H{sub 2} mixture ambient, the lowest resistivity of 8.17 × 10{sup −4} Ω cm, the highest electron concentration of 5.26 × 10{sup 20} cm{sup −3}, and the large band-gap of 3.8 eV were obtained, which is attributed to the hydrogen incorporation in film during annealing and the improved film crystal quality.

  15. SQIF Arrays as RF Sensors (Briefing Charts)

    National Research Council Canada - National Science Library

    Yukon, Stanford P

    2007-01-01

    ... (Superconducting Quantum Interference Filter) arrays may be employed as sensitive RF sensors. RF SQIF arrays fabricated with high Tc Josephson junctions can be cooled with small Sterling microcoolers...

  16. Optical Navigation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for a flexible navigation system for deep space operations that does not require GPS measurements. The navigation solution is computed using an...

  17. NIAAA Alcohol Treatment Navigator

    Science.gov (United States)

    ... FAQS Helpful Links Toolkit Find Your Way to Alcohol Treatment The search for alcohol treatment can feel ... and make a choice. Who is the NIAAA Alcohol Treatment Navigator SM for? The Navigator helps adults ...

  18. Matching Parasitic Antenna for Single RF MIMO

    DEFF Research Database (Denmark)

    Han, Bo; Kalis, A; Nielsen, Rasmus Hjorth

    2012-01-01

    Single RF MIMO communication emerges a novel low cost communication method which does not consume as much power as the conventional MIMO. The implementation of such single RF MIMO system is done by mapping the weighting factors to the polarizations or the radiation patterns of the antennas....... In order to have such performance, an antenna with rich pattern modes is required by the system, thus the ESPAR antenna is investigated. The critical part on such antenna is parasitic element impedance matching. Unlike the conventional smith-chart matching method which assumes the minimal resistance...... is zero and with goal of 50 ohm or 75 ohm matching, matching on such parasitic antenna will adopt negative value as well. This paper presents a matching network with controllable impedance even to the range of negative values....

  19. RF device forensics using passband filter analysis

    Science.gov (United States)

    King-Smith, Deen; Mikkilineni, Aravind K.; Gelfand, Saul; Delp, Edward J., III

    2009-02-01

    Given the wide use of Radio Frequency (RF) devices for applications ranging from data networks to wireless sensors, it is of interest to be able to characterize individual devices to verify compliance with FCC Part 15 rules. In an effort to characterize these types of devices we have developed a system that utilizes specially designed probe signals to elicit a response from the device from which unique characteristics can be extracted. The features that uniquely characterize a device are referred to as device signatures or device fingerprints. We apply this approach to RF devices which employ different bandpass filters, and construct training based classifiers which are highly accurate. We also introduce a model-based framework for optimal detection that can be employed to obtain performance limits, and to study model mismatch and probe optimization.

  20. Radar and electronic navigation

    CERN Document Server

    Sonnenberg, G J

    2013-01-01

    Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur

  1. Novel Photonic RF Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Leveraging on recent breakthroughs in broadband photonic devices and components for RF and microwave applications, SML proposes a new type of broadband microwave...

  2. Unbalanced field RF electron gun

    Science.gov (United States)

    Hofler, Alicia

    2013-11-12

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  3. Beam-Based Procedures for RF Guns

    CERN Document Server

    Krasilnikov, Mikhail; Grabosch, H J; Hartrott, Michael; Hui Han, Jang; Miltchev, Velizar; Oppelt, Anne; Petrosyan, Bagrat; Staykov, Lazar; Stephan, Frank

    2005-01-01

    A wide range of rf photo injector parameters has to be optimized in order to achieve an electron source performance as required for linac based high gain FELs. Some of the machine parameters can not be precisely controlled by direct measurements, whereas the tolerance on them is extremely tight. Therefore, this should be met with beam-based techniques. Procedures for beam-based alignment (BBA) of the laser on the photo cathode as well as solenoid alignment have been developed. They were applied at the Photo Injector Test facility at DESY Zeuthen (PITZ) and at the photo injector of the VUV-FEL at DESY Hamburg. A field balance of the accelerating mode in the 1 ½ cell gun cavity is one of the key beam dynamics issues of the rf gun. Since no direct field measurement in the half and full cell of the cavity is available for the PITZ gun, a beam-based technique to determine the field balance has been proposed. A beam-based rf phase monitoring procedure has been developed as well.

  4. Linked Autonomous Interplanetary Satellite Orbit Navigation

    Science.gov (United States)

    Parker, Jeffrey S.; Anderson, Rodney L.; Born, George H.; Leonard, Jason M.; McGranaghan, Ryan M.; Fujimoto, Kohei

    2013-01-01

    A navigation technology known as LiAISON (Linked Autonomous Interplanetary Satellite Orbit Navigation) has been known to produce very impressive navigation results for scenarios involving two or more cooperative satellites near the Moon, such that at least one satellite must be in an orbit significantly perturbed by the Earth, such as a lunar halo orbit. The two (or more) satellites track each other using satellite-to-satellite range and/or range-rate measurements. These relative measurements yield absolute orbit navigation when one of the satellites is in a lunar halo orbit, or the like. The geometry between a lunar halo orbiter and a GEO satellite continuously changes, which dramatically improves the information content of a satellite-to-satellite tracking signal. The geometrical variations include significant out-of-plane shifts, as well as inplane shifts. Further, the GEO satellite is almost continuously in view of a lunar halo orbiter. High-fidelity simulations demonstrate that LiAISON technology improves the navigation of GEO orbiters by an order of magnitude, relative to standard ground tracking. If a GEO satellite is navigated using LiAISON- only tracking measurements, its position is typically known to better than 10 meters. If LiAISON measurements are combined with simple radiometric ground observations, then the satellite s position is typically known to better than 3 meters, which is substantially better than the current state of GEO navigation. There are two features of LiAISON that are novel and advantageous compared with conventional satellite navigation. First, ordinary satellite-to-satellite tracking data only provides relative navigation of each satellite. The novelty is the placement of one navigation satellite in an orbit that is significantly perturbed by both the Earth and the Moon. A navigation satellite can track other satellites elsewhere in the Earth-Moon system and acquire knowledge about both satellites absolute positions and velocities

  5. Recent progress on improving ICRF coupling and reducing RF-specific impurities in ASDEX Upgrade

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2017-01-01

    Full Text Available The recent scientific research on ASDEX Upgrade (AUG has greatly advanced solutions to two issues of Radio Frequency (RF heating in the Ion Cyclotron Range of Frequencies (ICRF: (a the coupling of ICRF power to the plasma is significantly improved by density tailoring with local gas puffing; (b the release of RF-specific impurities is significantly reduced by minimizing the RF near field with 3-strap antennas. This paper summarizes the applied methods and reviews the associated achievements.

  6. Recent progress on improving ICRF coupling and reducing RF-specific impurities in ASDEX Upgrade

    Science.gov (United States)

    Zhang, Wei; Bobkov, Volodymyr; Noterdaeme, Jean-Marie; Tierens, Wouter; Aguiam, Diogo; Bilato, Roberto; Coster, David; Colas, Laurent; Crombé, Kristel; Fuenfgelder, Helmut; Faugel, Helmut; Feng, Yuhe; Jacquot, Jonathan; Jacquet, Philippe; Kallenbach, Arne; Kostic, Ana; Lunt, Tilmann; Maggiora, Riccardo; Ochoukov, Roman; Silva, Antonio; Suárez, Guillermo; Tuccilo, Angelo A.; Tudisco, Onofrio; Usoltceva, Mariia; Van Eester, Dirk; Wang, Yongsheng; Yang, Qingxi

    2017-10-01

    The recent scientific research on ASDEX Upgrade (AUG) has greatly advanced solutions to two issues of Radio Frequency (RF) heating in the Ion Cyclotron Range of Frequencies (ICRF): (a) the coupling of ICRF power to the plasma is significantly improved by density tailoring with local gas puffing; (b) the release of RF-specific impurities is significantly reduced by minimizing the RF near field with 3-strap antennas. This paper summarizes the applied methods and reviews the associated achievements.

  7. Studies of RF sheaths and diagnostics on IShTAR

    Energy Technology Data Exchange (ETDEWEB)

    Crombé, K., E-mail: Kristel.Crombe@UGent.be [Department of Applied Physics, Ghent University, Ghent (Belgium); LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium); Devaux, S.; Faudot, E.; Heuraux, S.; Moritz, J. [YIJL, UMR7198 CNRS-Université de Lorraine, Nancy (France); D’Inca, R.; Faugel, H.; Fünfgelder, H.; Jacquot, J.; Ochoukov, R. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Louche, F.; Tripsky, M.; Van Eester, D.; Wauters, T. [LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium); Noterdaeme, J.-M. [Department of Applied Physics, Ghent University, Ghent (Belgium); Max-Planck-Institut für Plasmaphysik, Garching (Germany)

    2015-12-10

    IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetised plasma test facility for RF sheaths studies at the Max-Planck-Institut für Plasmaphysik in Garching. In contrast to a tokamak, a test stand provides more liberty to impose the parameters and gives better access for the instrumentation and antennas. The project will support the development of diagnostic methods for characterising RF sheaths and validate and improve theoretical predictions. The cylindrical vacuum vessel has a diameter of 1 m and is 1.1 m long. The plasma is created by an external cylindrical plasma source equipped with a helical antenna that has been designed to excite the m=1 helicon mode. In inductive mode, plasma densities and electron temperatures have been characterised with a planar Langmuir probe as a function of gas pressure and input RF power. A 2D array of RF compensated Langmuir probes and a spectrometer are planned. A single strap RF antenna has been designed; the plasma-facing surface is aligned to the cylindrical plasma to ease the modelling. The probes will allow direct measurements of plasma density profiles in front of the RF antenna, and thus a detailed study of the density modifications induced by RF sheaths, which influences the coupling. The RF antenna frequency has been chosen to study different plasma wave interactions: the accessible plasma density range includes an evanescent and propagative behaviour of slow or fast waves, and allows the study of the effect of the lower hybrid resonance layer.

  8. Active experiments in geospace plasmas with gigawatts of RF power at HAARP

    Science.gov (United States)

    Sheerin, James

    2016-07-01

    The ionosphere provides a relatively quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8 - 10 MHz to the ionosphere with millisecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP's unique features have enabled the conduct of a number of nonlinear plasma experiments in the inter¬action region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and optics for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. Applications are made to the controlled study of fundamental nonlinear plasma processes of relevance to laboratory plasmas, ionospheric irregularities affecting spacecraft communication and navigation systems, artificial ionization mirrors, wave-particle interactions in the magnetosphere, active global magnetospheric experiments, and many more.

  9. Gamifying Navigation in Location-Based Applications

    DEFF Research Database (Denmark)

    Nadarajah, Stephanie Githa; Overgaard, Benjamin Nicholas; Pedersen, Peder Walz

    2017-01-01

    Location-based games entertain players usually by interactions at points of interest (POIs). Navigation between POIs often involve the use of either a physical or digital map, not taking advantage of the opportunity available to engage users in activities between POIs. The paper presents riddle...... solving as a navigational method for a location-based game. 10 families with 2-6 persons and at least one child in the age range 9-11 years old participated in the evaluation. Results show that riddle solving as a navigational method is more enjoyable than a 2D digital map. Additional findings from video...

  10. RF Group Annual Report 2011

    CERN Document Server

    Angoletta, M E; Betz, M; Brunner, O; Baudrenghien, P; Calaga, R; Caspers, F; Ciapala, E; Chambrillon, J; Damerau, H; Doebert, S; Federmann, S; Findlay, A; Gerigk, F; Hancock, S; Höfle, W; Jensen, E; Junginger, T; Liao, K; McMonagle, G; Montesinos, E; Mastoridis, T; Paoluzzi, M; Riddone, G; Rossi, C; Schirm, K; Schwerg, N; Shaposhnikova, E; Syratchev, I; Valuch, D; Venturini Delsolaro, W; Völlinger, C; Vretenar, M; Wuensch, W

    2012-01-01

    The highest priority for the RF group in 2011 was to contribute to a successful physics run of the LHC. This comprises operation of the superconducting 400 MHz accelerating system (ACS) and the transverse damper (ADT) of the LHC itself, but also all the individual links of the injector chain upstream of the LHC – Linac2, the PSB, the PS and the SPS – don’t forget that it is RF in all these accelerators that truly accelerates! A large variety of RF systems had to operate reliably, often near their limit. New tricks had to be found and implemented to go beyond limits; not to forget the equally demanding operation with Pb ions using in addition Linac3 and LEIR. But also other physics users required the full attention of the RF group: CNGS required in 2011 beams with very short, intense bunches, AD required reliable deceleration and cooling of anti-protons, Isolde the post-acceleration of radioactive isotopes in Rex, just to name a few. In addition to the supply of beams for physics, the RF group has a num...

  11. RF & wireless technologies know it all

    CERN Document Server

    Fette, Bruce A; Chandra, Praphul; Dobkin, Daniel M; Bensky, Dan; Miron, Douglas B; Lide, David; Dowla, Farid; Olexa, Ron

    2007-01-01

    The Newnes Know It All Series takes the best of what our authors have written to create hard-working desk references that will be an engineer's first port of call for key information, design techniques and rules of thumb. Guaranteed not to gather dust on a shelf!RF (radio frequency) and wireless technologies drive communication today. This technology and its applications enable wireless phones, portable device roaming, and short-range industrial and commercial application communication such as the supply chain management wonder, RFID. Up-to-date information regarding software defined R

  12. Nonlinear plasma experiments in geospace with gigawatts of RF power at HAARP

    Energy Technology Data Exchange (ETDEWEB)

    Sheerin, J. P., E-mail: jsheerin@emich.edu [Physics and Astronomy, Eastern Michigan Univ., Ypsilanti, MI 48197 (United States); Cohen, Morris B., E-mail: mcohen@gatech.edu [Electrical and Computer Engineering, Georgia Tech, Atlanta, GA 30332-0250 (United States)

    2015-12-10

    The ionosphere is the ionized uppermost layer of our atmosphere (from 70 – 500 km altitude) where free electron densities yield peak critical frequencies in the HF (3 – 30 MHz) range. The ionosphere thus provides a quiescent plasma target, stable on timescales of minutes, for a whole host of active plasma experiments. High power RF experiments on ionospheric plasma conducted in the U.S. have been reported since 1970. The largest HF transmitter built to date is the HAARP phased-array HF transmitter near Gakona, Alaska which can deliver up to 3.6 Gigawatts (ERP) of CW RF power in the range of 2.8 – 10 MHz to the ionosphere with microsecond pointing, power modulation, and frequency agility. With an ionospheric background thermal energy in the range of only 0.1 eV, this amount of power gives access to the highest regimes of the nonlinearity (RF intensity to thermal pressure) ratio. HAARP’s unique features have enabled the conduct of a number of unique nonlinear plasma experiments in the interaction region of overdense ionospheric plasma including generation of artificial aurorae, artificial ionization layers, VLF wave-particle interactions in the magnetosphere, parametric instabilities, stimulated electromagnetic emissions (SEE), strong Langmuir turbulence (SLT) and suprathermal electron acceleration. Diagnostics include the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the SuperDARN-Kodiak HF radar, spacecraft radio beacons, HF receivers to record stimulated electromagnetic emissions (SEE) and telescopes and cameras for optical emissions. We report on short timescale ponderomotive overshoot effects, artificial field-aligned irregularities (AFAI), the aspect angle dependence of the intensity of the HF-enhanced plasma line, and production of suprathermal electrons. One of the primary missions of HAARP, has been the generation of ELF (300 – 3000 Hz) and VLF (3 – 30 kHz) radio waves which are guided to global distances in the Earth

  13. Mixing navigation on networks

    Science.gov (United States)

    Zhou, Tao

    2008-05-01

    In this article, we propose a mixing navigation mechanism, which interpolates between random-walk and shortest-path protocol. The navigation efficiency can be remarkably enhanced via a few routers. Some advanced strategies are also designed: For non-geographical scale-free networks, the targeted strategy with a tiny fraction of routers can guarantee an efficient navigation with low and stable delivery time almost independent of network size. For geographical localized networks, the clustering strategy can simultaneously increase efficiency and reduce the communication cost. The present mixing navigation mechanism is of significance especially for information organization of wireless sensor networks and distributed autonomous robotic systems.

  14. Indoor wayfinding and navigation

    CERN Document Server

    2015-01-01

    Due to the widespread use of navigation systems for wayfinding and navigation in the outdoors, researchers have devoted their efforts in recent years to designing navigation systems that can be used indoors. This book is a comprehensive guide to designing and building indoor wayfinding and navigation systems. It covers all types of feasible sensors (for example, Wi-Fi, A-GPS), discussing the level of accuracy, the types of map data needed, the data sources, and the techniques for providing routes and directions within structures.

  15. Connect Global Positioning System RF Module

    Science.gov (United States)

    Franklin, Garth W.; Young, Lawrence E.; Ciminera, Michael A.; Tien, Jeffrey Y.; Gorelik, Jacob; Okihiro, Brian Bachman; Koelewyn, Cynthia L.

    2012-01-01

    The CoNNeCT Global Positioning System RF Module (GPSM) slice is part of the JPL CoNNeCT Software Defined Radio (SDR). CoNNeCT is the Communications, Navigation, and Net working reconfigurable Testbed project that is part of NASA's Space Communication and Nav igation (SCaN) Program. The CoNNeCT project is an experimental dem onstration that will lead to the advancement of SDRs and provide a path for new space communication and navigation systems for future NASA exploration missions. The JPL CoNNeCT SDR will be flying on the International Space Station (ISS) in 2012 in support of the SCaN CoNNeCT program. The GPSM is a radio-frequency sampler module (see Figure 1) that directly sub-harmonically samples the filtered GPS L-band signals at L1 (1575.42 MHz), L2 (1227.6 MHz), and L5 (1176.45 MHz). The JPL SDR receives GPS signals through a Dorne & Margolin antenna mounted onto a choke ring. The GPS signal is filtered against interference, amplified, split, and fed into three channels: L1, L2, and L5. In each of the L-band channels, there is a chain of bandpass filters and amplifiers, and the signal is fed through each of these channels to where the GPSM performs a one-bit analog-to-digital conversion (see Figure 2). The GPSM uses a sub-harmonic, single-bit L1, L2, and L5 sampler that samples at a clock rate of 38.656 MHz. The new capability is the down-conversion and sampling of the L5 signal when previous hardware did not provide this capability. The first GPS IIF Satellite was launched in 2010, providing the new L5 signal. With the JPL SDR flying on the ISS, it will be possible to demonstrate navigation solutions with 10-meter 3-D accuracy at 10-second intervals using a field-program mable gate array (FPGA)-based feedback loop running at 50 Hz. The GPS data bits will be decoded and used in the SDR. The GPSM will also allow other waveforms that are installed in the SDR to demonstrate various GNSS tracking techniques.

  16. Autonomous robot navigation: appearance based topological SLAM

    OpenAIRE

    Lui, Wen Lik Dennis

    2017-01-01

    The main focus of this research is to develop an autonomous robot capable of self-navigation in an unknown environment. The proposed system performs autonomous navigation primarily based on the following visually perceived information: 1) Range Estimation: A novel variable single/multi baseline omnidirectional stereovision system with an option to automatically select the baseline that is adjusted to the environment with the establishment of stereo correspondences and triangulation offloa...

  17. Ion bombardment in RF photoguns

    Energy Technology Data Exchange (ETDEWEB)

    Pozdeyev,E.; Kayran, D.; Litvinenko, V. N.

    2009-05-04

    A linac-ring eRHIC design requires a high-intensity CW source of polarized electrons. An SRF gun is viable option that can deliver the required beam. Numerical simulations presented elsewhere have shown that ion bombardment can occur in an RF gun, possibly limiting lifetime of a NEA GaAs cathode. In this paper, we analytically solve the equations of motion of ions in an RF gun using the ponderomotive potential of the Rf field. We apply the method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of ions produced in the gun can reach the cathode if no special precautions are taken. Also, the paper discusses possible mitigation techniques that can reduce the rate of ion bombardment.

  18. R & D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yonehara, K. [Fermilab; Backfish, M. [Fermilab; Moretti, A. [Fermilab; Tollestrup, A. V. [Fermilab; Watts, A. [Fermilab; Zwaska, R. M. [Fermilab; Abrams, R. [MUONS Inc., Batavia; Cummings, M. A.; Dudas, A. [MUONS Inc., Batavia; Johnson, R. P. [MUONS Inc., Batavia; Kazakevich, G. [MUONS Inc., Batavia; Neubauer, M. [MUONS Inc., Batavia; Liu, Q. [Case Western Reserve U.

    2017-05-01

    We report the R&D of a novel radiation-robust hadron beam profile monitor based on a gas-filled RF cavity for intense neutrino beam experiments. An equivalent RF circuit model was made and simulated to optimize the RF parameter in a wide beam intensity range. As a result, the maximum acceptable beam intensity in the monitor is significantly increased by using a low-quality factor RF cavity. The plan for the demonstration test is set up to prepare for future neutrino beam experiments.

  19. RF Loads for Energy Recovery

    CERN Document Server

    Federmann, S; Caspers, F

    2012-01-01

    Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ◦C) are discussed. Another design deals with a very high temperature (up to 800 ◦C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the microwave absorber and is not brazed to the metallic enclosure.

  20. Methodology for performing RF reliability experiments on a generic test structure

    NARCIS (Netherlands)

    Sasse, G.T.; de Vries, Rein J.; Schmitz, Jurriaan

    2007-01-01

    This paper discusses a new technique developed for generating well defined RF large voltage swing signals for on wafer experiments. This technique can be employed for performing a broad range of different RF reliability experiments on one generic test structure. The frequency dependence of a

  1. Maps and navigation methods

    Science.gov (United States)

    Duval, A

    1922-01-01

    Different maps and scales are discussed with particular emphasis on their use in aviation. The author makes the observation that current navigation methods are slow and dangerous and should be replaced by scientific methods of navigation based on loxodromy and the use of the compass.

  2. Geo Embedded Navigation

    DEFF Research Database (Denmark)

    Ilsøe, Peer Møller; Kolar, Jan

    2005-01-01

    challenges in this context is to develop a simple and intuitive general purpose navigation mode that will work well for a single planet from outer space to a street level. Such works are missing today. Although the need for global navigation in disaster management is rather conceptual than practical...

  3. Liquid Metal Droplet and Micro Corrugated Diaphragm RF-MEMS for reconfigurable RF filters

    Science.gov (United States)

    Irshad, Wasim

    detail and have proved pivotal to this work. The second part of the dissertation focuses on the Liquid Metal Droplet RF-MEMS. A novel tunable RF MEMS resonator that is based upon electrostatic control over the morphology of a liquid metal droplet (LMD) is conceived. We demonstrate an LMD evanescent-mode cavity resonator that simultaneously achieves wide analog tuning from 12 to 18 GHz with a measured quality factor of 1400-1840. A droplet of 250-mum diameter is utilized and the applied bias is limited to 100 V. This device operates on a principle called Electro-Wetting On Dielectric (EWOD). The liquid metal employed is a non-toxic eutectic alloy of Gallium, Indium and Tin known as Galinstan. This device also exploits interfacial surface energy and viscous body forces that dominate at nanoliter scale. We then apply our Liquid Metal Droplet (LMD) RF-MEMS architecture to demonstrate a continuously tunable electrostatic Ku-Band Filter. A 2-pole bandpass filter with measured insertion loss of less than 0.4dB and 3dB FBW of 3.4% is achieved using a Galinstan droplet of 250mum diameter and bias limited to 100V. We demonstrate that the LMD is insensitive to gravity by performing inversion and tilt experiments. In addition, we study its thermal tolerance by subjecting the LMD up to 150° C. The third part of the dissertation is dedicated to the Micro-Corrugated Diaphragm (MCD) RF-MEMS. We present an evanescent-mode cavity bandpass filter with state-of-the-art RF performance metrics like 4:1 tuning ratio from 5 to 20 GHz with less than 2dB insertion loss and 2-6% 3dB bandwidth. Micro-Corrugated Diaphragm (MCD) is a novel electrostatic MEMS design specifically engineered to provide large-scale analog deflections necessary for such continuous and wide tunable filtering with very high quality factor. We demonstrate a 1.25mm radius and 2mum thick Gold MCD which provides 30mum total deflection with nearly 60% analog range. We also present a detailed and systematic MCD design

  4. Use of real-time GNSS-RF data to characterize the swing movements of forestry equipment

    Science.gov (United States)

    Ryer M. Becker; Robert F. Keefe; Nathaniel M. Anderson

    2017-01-01

    The western United States faces significant forest management challenges after severe bark beetle infestations have led to substantial mortality. Minimizing costs is vital for increasing the feasibility of management operations in affected forests. Multi‐transmitter Global Navigation Satellite System (GNSS)‐radio frequencies (RF) technology has applications in the...

  5. Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation.

    Science.gov (United States)

    Zimbelman, Eloise G; Keefe, Robert F

    2018-01-01

    Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.

  6. Reliability engineering in RF CMOS

    NARCIS (Netherlands)

    Sasse, G.T.

    2008-01-01

    In this thesis new developments are presented for reliability engineering in RF CMOS. Given the increase in use of CMOS technology in applications for mobile communication, also the reliability of CMOS for such applications becomes increasingly important. When applied in these applications, CMOS is

  7. Broadband direct RF digitization receivers

    CERN Document Server

    Jamin, Olivier

    2014-01-01

    This book discusses the trade-offs involved in designing direct RF digitization receivers for the radio frequency and digital signal processing domains.  A system-level framework is developed, quantifying the relevant impairments of the signal processing chain, through a comprehensive system-level analysis.  Special focus is given to noise analysis (thermal noise, quantization noise, saturation noise, signal-dependent noise), broadband non-linear distortion analysis, including the impact of the sampling strategy (low-pass, band-pass), analysis of time-interleaved ADC channel mismatches, sampling clock purity and digital channel selection. The system-level framework described is applied to the design of a cable multi-channel RF direct digitization receiver. An optimum RF signal conditioning, and some algorithms (automatic gain control loop, RF front-end amplitude equalization control loop) are used to relax the requirements of a 2.7GHz 11-bit ADC. A two-chip implementation is presented, using BiCMOS and 65nm...

  8. RF breakdown by toroidal helicons

    Indian Academy of Sciences (India)

    Bounded whistlers are well-known for their efficient plasma production capabilities in thin cylindrical tubes. ... evolution processes in a pulse RF plasma produced by toroidal helicons. 2. Experimental set-up and .... of probe potential to show initial hump and transient nature of sheath at the end of the pulse. It is to check the ...

  9. Effects of rf power on electron density and temperature, neutral temperature, and Te fluctuations in an inductively coupled plasma

    Science.gov (United States)

    Camparo, James; Fathi, Gilda

    2009-05-01

    Atomic clocks that fly on global-navigation satellites such as global positioning system (GPS) and Galileo employ light from low-temperature, inductively coupled plasmas (ICPs) for atomic signal generation and detection (i.e., alkali/noble-gas rf-discharge lamps). In this application, the performance of the atomic clock and the capabilities of the navigation system depend sensitively on the stability of the ICP's optical emission. In order to better understand the mechanisms that might lead to instability in these rf-discharge lamps, and hence the satellite atomic clocks, we studied the optical emission from a Rb/Xe ICP as a function of the rf power driving the plasma. Surprisingly, we found that the electron density in the plasma was essentially independent of increases in rf power above its nominal value (i.e., "rf-power gain") and that the electron temperature was only a slowly varying function of rf-power gain. The primary effect of rf power was to increase the temperature of the neutrals in the plasma, which was manifested by an increase in Rb vapor density. Interestingly, we also found evidence for electron temperature fluctuations (i.e., fluctuations in the plasma's high-energy electron content). The variance of these fluctuations scaled inversely with the plasma's mean electron temperature and was consistent with a simple model that assumed that the total electron density in the discharge was independent of rf power. Taken as a whole, our results indicate that the electrons in alkali/noble-gas ICPs are little affected by slight changes in rf power and that the primary effect of such changes is to heat the plasma's neutral species.

  10. Restricted Navigation Areas - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  11. Passive RF component technology materials, techniques, and applications

    CERN Document Server

    Wang, Guoan

    2012-01-01

    Focusing on novel materials and techniques, this pioneering volume provides you with a solid understanding of the design and fabrication of smart RF passive components. You find comprehensive details on LCP, metal materials, ferrite materials, nano materials, high aspect ratio enabled materials, green materials for RFID, and silicon micromachining techniques. Moreover, this practical book offers expert guidance on how to apply these materials and techniques to design a wide range of cutting-edge RF passive components, from MEMS switch based tunable passives and 3D passives, to metamaterial-bas

  12. Portable 433 MHz RFQ linac RF system

    Energy Technology Data Exchange (ETDEWEB)

    Vorogushin, M.F. [Efremov Scientific Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation)

    1994-12-31

    Principle and experimental analysis of RF power feed system, based on 3 db directional couplers, for undesirable modes eliminating, divided power coupling with the RFQ accelerating structure, endotron type RF power source matching, are presented. The structure fine tuning and the system adjustment results and high-speed RF autocontrol system design are considered also.

  13. RF digital-to-analog converter

    Science.gov (United States)

    Conway, P.H.; Yu, D.U.L.

    1995-02-28

    A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

  14. Glycol-Substitute for High Power RF Water Loads

    CERN Document Server

    Ebert, Michael

    2005-01-01

    In water loads for high power rf applications, power is dissipated directly into the coolant. Loads for frequencies below approx. 1GHz are ordinarily using an ethylene glycol-water mixture as coolant. The rf systems at DESY utilize about 100 glycol water loads with powers ranging up to 600kW. Due to the increased ecological awareness, the use of glycol is now considered to be problematic. In EU it is forbidden to discharge glycol into the waste water system. In case of cooling system leakages one has to make sure that no glycol is lost. Since it is nearly impossible to avoid any glycol loss in large rf systems, a glycol-substitute was searched for and found. The found sodium-molybdate based substitute is actually a additive for corrosion protection in water systems. Sodium-molybdate is ecologically harmless; for instance, it is also used as fertilizer in agriculture. A homoeopathic dose of 0.4% mixed into deionised water gives better rf absorption characteristics than a 30% glycol mixture. The rf coolant feat...

  15. The RF Cycle of the PIMMS Medical Synchrotron

    CERN Document Server

    Crescenti, M; Knaus, P

    2000-01-01

    This paper presents the design of the RF cycle of the medical synchrotron of the PIMMS (Proton-Ion Medical Machine Study) hosted at CERN. The cycle comprises adiabatic trapping, acceleration and RF gymnastics, for either protons or fully stripped carbon ions. The injection energy is 20 MeV for protons and 7 MeV/u for carbon. Maximum extraction energies are 250 MeV for protons and 400 MeV/u for carbon ions. The cycle duration is less than 1 s, with a maximum magnetic field ramp below 3 T/s. The simulations show that the beam stays inside the aperture of the machine, and that, theoretically, there are no longitudinal losses. At the end of the cycle, the beam is ready for extraction with a Dp/p = 0.4 %. The peak RF voltage is 3 kV and the frequency ranges from 0.4 to 3 MHz.

  16. Getting Lost Through Navigation

    DEFF Research Database (Denmark)

    Debus, Michael S.

    2017-01-01

    In this presentation, I argued two things. First, that it is navigation that lies at the core of contemporary (3D-) videogames and that its analysis is of utmost importance. Second, that this analysis needs a more rigorous differentiation between specific acts of navigation. Considering the Oxford...... in videogames is a configurational rather than an interpretational one (Eskelinen 2001). Especially in the case of game spaces, navigation appears to be of importance (Wolf 2009; Flynn 2008). Further, it does not only play a crucial role for the games themselves, but also for the experience of the player...

  17. Navigation by images

    Directory of Open Access Journals (Sweden)

    Espen Hagen

    1993-07-01

    Full Text Available A new navigation method based on measurements of image tokens and Kalman filtering is presented. An image token is the central projection of a landmark, a point on the terrain surface. This surface being described by an elevation map, a Kalman filter processes the measurements to update estimates of camera position and orientation, and landmarks. The method has been implemented for off-line simulations of aeroplane navigation. Preliminary tests indicate a performance at least comparable to that of satellite navigation systems. The implemented algorithm also seems to have high tolerance against noise and modeling errors.

  18. Rf cavity primer for cyclic proton accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, J.E.

    1988-04-01

    The purpose of this note is to describe the electrical and mechanical properites of particle accelerator rf cavities in a manner which will be useful to physics and engineering graduates entering the accelerator field. The discussion will be limited to proton (or antiproton) synchrotron accelerators or storage rings operating roughly in the range of 20 to 200 MHz. The very high gradient, fixed frequency UHF or microwave devices appropriate for electron machines and the somewhat lower frequency and broader bandwidth devices required for heavy ion accelerators are discussed extensively in other papers in this series. While it is common pratice to employ field calculation programs such as SUPERFISH, URMEL, or MAFIA as design aids in the development of rf cavities, we attempt here to elucidate various of the design parameters commonly dealt with in proton machines through the use of simple standing wave coaxial resonator expressions. In so doing, we treat only standing wave structures. Although low-impedance, moderately broad pass-band travelling wave accelerating systems are used in the CERN SPS, such systems are more commonly found in linacs, and they have not been used widely in large cyclic accelerators. Two appendices providing useful supporting material regarding relativistic particle dynamics and synchrotron motion in cyclic accelerators are added to supplement the text.

  19. The Witch Navigator - A Low Cost GNSS Software Receiver for Advanced Processing Techniques

    Directory of Open Access Journals (Sweden)

    O. Jakubov

    2010-12-01

    Full Text Available The developement of advanced GNSS signal processing algorithms such as multi-constellation, multi-frequency and multi-antenna navigation requires an easily reprogrammable software defined radio solution. Various receiver architectures for this purpose have been introduced. RF front-end with FPGA universal correlators on ExpressCard connected directly to PC was selected and manufactured. Such a~unique hardware combination provides the GNSS researchers and engineers with a~great convenience of writing the signal processing algorithms including tracking, acquisition and positioning in the Linux application programming interface and enables them to reconfigure the RF front-end easily by the PC program. With more of these ExpressCards connected to the PC, the number of the RF channels, correlators or antennas can be increased to further boost the computational power. This paper reveals the implementation aspects of the receiver, named the Witch Navigator, and~gives the key test results.

  20. [Navigated retinal laser therapy].

    Science.gov (United States)

    Kernt, M; Ulbig, M; Kampik, A; Neubauer, A S

    2013-08-01

    Navigated laser therapy introduces for the first time computerized assistance systems for retinal laser therapy. The Navilas system offers high precision and safety and provides additional benefits regarding standardization of planning, execution, documentation and quality assurance. The current focus of clinical application for navigated laser therapy besides laser treatment after retinal vein occlusion and panretinal laser photocoagulation in proliferative diabetic retinopathy (PDR) is diabetic macular edema. Recent data indicate that combined initial anti-vascular endothelial growth factor (anti-VEGF) and navigated macular laser therapy allows achievement and maintenance of treatment success with a minimum number of interventions. Despite very promising results the current assessment of navigated laser therapy is still limited by the evidence available worldwide.

  1. USACE Navigation Channels 2012

    Data.gov (United States)

    California Department of Resources — This dataset represents both San Francisco and Los Angeles District navigation channel lines. All San Francisco District channel lines were digitized from CAD files...

  2. Protection of Accelerator Hardware: RF systems

    CERN Document Server

    Kim, S.-H.

    2016-01-01

    The radio-frequency (RF) system is the key element that generates electric fields for beam acceleration. To keep the system reliable, a highly sophisticated protection scheme is required, which also should be designed to ensure a good balance between beam availability and machine safety. Since RF systems are complex, incorporating high-voltage and high-power equipment, a good portion of machine downtime typically comes from RF systems. Equipment and component damage in RF systems results in long and expensive repairs. Protection of RF system hardware is one of the oldest machine protection concepts, dealing with the protection of individual high-power RF equipment from breakdowns. As beam power increases in modern accelerators, the protection of accelerating structures from beam-induced faults also becomes a critical aspect of protection schemes. In this article, an overview of the RF system is given, and selected topics of failure mechanisms and examples of protection requirements are introduced.

  3. SPS RF System a Tetrode

    CERN Multimedia

    1974-01-01

    The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

  4. Linearisation of RF Power Amplifiers

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck

    2001-01-01

    of circuitry such as the linearisation circuit. The amplifier has the highest output power compared to other published class B power in the same process. The design phase including the on-chip inductor and the lateral flux capacitors is described. The other test chips designed are envelope detectors. Three......This thesis deals with linearisation techniques of RF power amplifiers (PA), PA design techniques and integration of the necessary building blocks in a CMOS technology. The opening chapters introduces the theory of transmitter architectures, RF-signal representation and the principles of digital...... modulation. Furthermore different types of power amplifiers, models and measures of non-linearities are presented. A chapter is also devoted to different types of linearisation systems. The work carried out and described in this thesis can be divided into a more theoretical and system oriented treatment...

  5. Low jitter RF distribution system

    Science.gov (United States)

    Wilcox, Russell; Doolittle, Lawrence; Huang, Gang

    2012-09-18

    A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

  6. A Study of Direct Digital Manufactured RF/Microwave Packaging

    Science.gov (United States)

    Stratton, John W. I.

    Various facets of direct digital manufactured (DDM) microwave packages are studied. The rippled surface inherent in fused deposition modeling (FDM) fabricated geometries is modeled in Ansoft HFSS, and its effect on the performance of microstrip transmission lines is assessed via simulation and measurement. The thermal response of DDM microstrip transmission lines is analyzed over a range of RF input powers, and linearity is confirmed over that range. Two IC packages are embedded into DDM printed circuit boards, and their performance is analyzed. The first is a low power RF switch, and the second is an RF front end device that includes a low noise amplifier (LNA) and a power amplifier (PA). The RF switch is shown to perform well, as compared to a layout designed for a Rogers 4003C microwave laminate substrate. The LNA performs within datasheet specifications. The power amplifier generates substantial heat, so a thermal management attempt is described. Finally, a capacitively loaded 6dB Wilkinson power divider is designed and fabricated using DDM techniques and materials. Its performance is analyzed and compared to simulation. The device is shown to compare favorably to a similar device fabricated on a Rogers 4003C microwave laminate using traditional printed circuit board techniques.

  7. Fuzzy Logic Based Control for Autonomous Mobile Robot Navigation.

    Science.gov (United States)

    Omrane, Hajer; Masmoudi, Mohamed Slim; Masmoudi, Mohamed

    This paper describes the design and the implementation of a trajectory tracking controller using fuzzy logic for mobile robot to navigate in indoor environments. Most of the previous works used two independent controllers for navigation and avoiding obstacles. The main contribution of the paper can be summarized in the fact that we use only one fuzzy controller for navigation and obstacle avoidance. The used mobile robot is equipped with DC motor, nine infrared range (IR) sensors to measure the distance to obstacles, and two optical encoders to provide the actual position and speeds. To evaluate the performances of the intelligent navigation algorithms, different trajectories are used and simulated using MATLAB software and SIMIAM navigation platform. Simulation results show the performances of the intelligent navigation algorithms in terms of simulation times and travelled path.

  8. Fuzzy Logic Based Control for Autonomous Mobile Robot Navigation

    Directory of Open Access Journals (Sweden)

    Hajer Omrane

    2016-01-01

    Full Text Available This paper describes the design and the implementation of a trajectory tracking controller using fuzzy logic for mobile robot to navigate in indoor environments. Most of the previous works used two independent controllers for navigation and avoiding obstacles. The main contribution of the paper can be summarized in the fact that we use only one fuzzy controller for navigation and obstacle avoidance. The used mobile robot is equipped with DC motor, nine infrared range (IR sensors to measure the distance to obstacles, and two optical encoders to provide the actual position and speeds. To evaluate the performances of the intelligent navigation algorithms, different trajectories are used and simulated using MATLAB software and SIMIAM navigation platform. Simulation results show the performances of the intelligent navigation algorithms in terms of simulation times and travelled path.

  9. Remarks on the observability of single beacon underwater navigation

    DEFF Research Database (Denmark)

    Jouffroy, Jerome; Ross, Andrew

    This paper contributes a simple and intuitive result in the analysis of underwater navigation using a single ranging beacon. This analysis should help with the design of small and lightweight underwater vehicles by reducing the amount of instrumentation required for accurate navigation. The concept...

  10. Toward High-Power Klystrons With RF Power Conversion Efficiency on the Order of 90%

    CERN Document Server

    Baikov, Andrey Yu; Syratchev, Igor

    2015-01-01

    The increase in efficiency of RF power generation for future large accelerators is considered a high priority issue. The vast majority of the existing commercial high-power RF klystrons operates in the electronic efficiency range between 40% and 55%. Only a few klystrons available on the market are capable of operating with 65% efficiency or above. In this paper, a new method to achieve 90% RF power conversion efficiency in a klystron amplifier is presented. The essential part of this method is a new bunching technique - bunching with bunch core oscillations. Computer simulations confirm that the RF production efficiency above 90% can be reached with this new bunching method. The results of a preliminary study of an L-band, 20-MW peak RF power multibeam klystron for Compact Linear Collider with the efficiency above 85% are presented.

  11. Patient navigation: state of the art or is it science?

    Science.gov (United States)

    Wells, Kristen J; Battaglia, Tracy A; Dudley, Donald J; Garcia, Roland; Greene, Amanda; Calhoun, Elizabeth; Mandelblatt, Jeanne S; Paskett, Electra D; Raich, Peter C

    2008-10-15

    First implemented in 1990, patient navigation interventions are emerging today as an approach to reduce cancer disparities. However, there is lack of consensus about how patient navigation is defined, what patient navigators do, and what their qualifications should be. Little is known about the efficacy and cost-effectiveness of patient navigation. For this review, the authors conducted a qualitative synthesis of published literature on cancer patient navigation. By using the keywords 'navigator' or 'navigation' and 'cancer,' 45 articles were identified in the PubMed database and from reference searches that were published or in press through October 2007. Sixteen studies provided data on the efficacy of navigation in improving timeliness and receipt of cancer screening, diagnostic follow-up care, and treatment. Patient navigation services were defined and differentiated from other outreach services. Overall, there was evidence of some degree of efficacy for patient navigation in increasing participation in cancer screening and adherence to diagnostic follow-up care after the detection of an abnormality. The reported increases in screening ranged from 10.8% to 17.1%, and increases in adherence to diagnostic follow-up care ranged from 21% to 29.2% compared with control patients. There was less evidence regarding the efficacy of patient navigation in reducing either late-stage cancer diagnosis or delays in the initiation of cancer treatment or improving outcomes during cancer survivorship. There were methodological limitations in most studies, such as a lack of control groups, small sample sizes, and contamination with other interventions. Although cancer-related patient navigation interventions are being adopted increasingly across the United States and Canada, further research will be necessary to evaluate their efficacy and cost-effectiveness in improving cancer care. (c) 2008 American Cancer Society.

  12. Collapsed fat navigators for brain 3D rigid body motion.

    Science.gov (United States)

    Engström, Mathias; Mårtensson, Magnus; Avventi, Enrico; Norbeck, Ola; Skare, Stefan

    2015-10-01

    To acquire high-resolution 3D multi-slab echo planar imaging data without motion artifacts, using collapsed fat navigators. A fat navigator module (collapsed FatNav) was added to a diffusion-weighted 3D multi-slab echo planar imaging (DW 3D-MS EPI) sequence, comprising three orthogonal echo planar imaging readouts to track rigid body head motion in the image domain and performing prospective motion correction. The stability, resolution and accuracy of the navigator were investigated on phantoms and healthy volunteers. The experiments on phantoms and volunteers show that the navigator, depicting projections of the subcutaneous fat in of the head, is capable of correcting for head motion with insignificant bias compared to motion estimates derived from the water-signaling DWI images. Despite that this projection technique implies a non-sparse image appearance, collapsed FatNav data could be highly accelerated with parallel imaging, allowing three orthogonal 2D EPI readouts in about 6ms. By utilizing signal from the leading fat saturation RF pulse of the diffusion sequence, only the readout portion of the navigator needs to be added, resulting in a scan time penalty of only about 5%. Motion can be detected and corrected for with a 5-10Hz update frequency when combined with a sequence like the DW 3D-MS EPI. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Analysis of Passive RF-DC Power Rectification and Harvesting Wireless RF Energy for Micro-watt Sensors

    Directory of Open Access Journals (Sweden)

    Antwi Nimo

    2015-04-01

    Full Text Available In this paper, analytical modeling of passive rectifying circuits and the harvesting of electromagnetic (EM power from intentionally generated as well as from ubiquitous sources are presented. The presented model is based on the linearization of rectifying circuits. The model provides an accurate method of determining the output characteristics of rectifying circuits. The model was verified with Advance Design System (ADS Harmonic balance (HB simulations and measurements. The results from the presented model were in agreement with simulations and measurements. Consequently design considerations and trade-off of radio frequency (RF harvesters are discussed. To verify the exploitation of ambient RF power sources for operation of sensors, a dual-band antenna with a size of ~λ/4 at 900MHz and a passive dual-band rectifier that is able to power a commercial Thermo-Hygrometer requiring ~1.3V and 0.5MΩ from a global system for mobile communications (GSM base station is demonstrated. The RF power delivered by the receiving dual-band antenna at a distance of about 110 m from the GSM base station ranges from -27 dBm to -50 dBm from the various GSM frequency bands. Additionally, wireless range measurements of the RF harvesters in the industrial, scientific and medical (ISM band 868MHz is presented at indoor conditions.

  14. Lunar rover navigation concepts

    Science.gov (United States)

    Burke, James D.

    1993-01-01

    With regard to the navigation of mobile lunar vehicles on the surface, candidate techniques are reviewed and progress of simulations and experiments made up to now are described. Progress that can be made through precursor investigations on Earth is considered. In the early seventies the problem was examined in a series of relevant tests made in the California desert. Meanwhile, Apollo rovers made short exploratory sorties and robotic Lunokhods traveled over modest distances on the Moon. In these early missions some of the required methods were demonstrated. The navigation problem for a lunar traverse can be viewed in three parts: to determine the starting point with enough accuracy to enable the desired mission; to determine the event sequence required to reach the site of each traverse objective; and to redetermine actual positions enroute. The navigator's first tool is a map made from overhead imagery. The Moon was almost completely photographed at moderate resolution by spacecraft launched in the sixties, but that data set provides imprecise topographic and selenodetic information. Therefore, more advanced orbital missions are now proposed as part of a resumed lunar exploration program. With the mapping coverage expected from such orbiters, it will be possible to use a combination of visual landmark navigation and external radio and optical references (Earth and Sun) to achieve accurate surface navigation almost everywhere on the near side of the Moon. On the far side and in permanently dark polar areas, there are interesting exploration targets where additional techniques will have to be used.

  15. RF and microwave microelectronics packaging II

    CERN Document Server

    Sturdivant, Rick

    2017-01-01

    Reviews RF, microwave, and microelectronics assembly process, quality control, and failure analysis Bridges the gap between low cost commercial and hi-res RF/Microwave packaging technologies Engages in an in-depth discussion of challenges in packaging and assembly of advanced high-power amplifiers This book presents the latest developments in packaging for high-frequency electronics. It is a companion volume to “RF and Microwave Microelectronics Packaging” (2010) and covers the latest developments in thermal management, electrical/RF/thermal-mechanical designs and simulations, packaging and processing methods, and other RF and microwave packaging topics. Chapters provide detailed coverage of phased arrays, T/R modules, 3D transitions, high thermal conductivity materials, carbon nanotubes and graphene advanced materials, and chip size packaging for RF MEMS. It appeals to practicing engineers in the electronic packaging and high-frequency electronics domain, and to academic researchers interested in underst...

  16. Moscow Meson Factory DTL RF System Upgrade

    CERN Document Server

    Esin, S K; Kvasha, A I; Serov, V L

    2004-01-01

    The last paper devoted to description of the first part (DTL) RF system of Moscow Meson Factory upgrade was published in the Proceedings of PAC95 Conference in Dallas. Since then some new works directed at improvement of reliability and efficiency of the RF system were carried out. Among them there are a new powerful pulse triode “Katran” installed in the output RF power amplifiers (PA) of three channels, modifications of the anode modulator control circuit and crow-bar system, a new additional RF channel for RF supply of RFQ and some alterations in placing of the anode modulator equipment decreasing a level of interference’s at crow-bar circuits. Some new checked at MMF RF channels ideas concerning of PA tuning are of interest for people working in this sphere of activity.

  17. Robust multiplatform RF emitter localization

    Science.gov (United States)

    Al Issa, Huthaifa; Ordóñez, Raúl

    2012-06-01

    In recent years, position based services has increase. Thus, recent developments in communications and RF technology have enabled system concept formulations and designs for low-cost radar systems using state-of-the-art software radio modules. This research is done to investigate a novel multi-platform RF emitter localization technique denoted as Position-Adaptive RF Direction Finding (PADF). The formulation is based on the investigation of iterative path-loss (i.e., Path Loss Exponent, or PLE) metrics estimates that are measured across multiple platforms in order to autonomously adapt (i.e. self-adjust) of the location of each distributed/cooperative platform. Experiments conducted at the Air-Force Research laboratory (AFRL) indicate that this position-adaptive approach exhibits potential for accurate emitter localization in challenging embedded multipath environments such as in urban environments. The focus of this paper is on the robustness of the distributed approach to RF-based location tracking. In order to localize the transmitter, we use the Received Signal Strength Indicator (RSSI) data to approximate distance from the transmitter to the revolving receivers. We provide an algorithm for on-line estimation of the Path Loss Exponent (PLE) that is used in modeling the distance based on Received Signal Strength (RSS) measurements. The emitter position estimation is calculated based on surrounding sensors RSS values using Least-Square Estimation (LSE). The PADF has been tested on a number of different configurations in the laboratory via the design and implementation of four IRIS wireless sensor nodes as receivers and one hidden sensor as a transmitter during the localization phase. The robustness of detecting the transmitters position is initiated by getting the RSSI data through experiments and then data manipulation in MATLAB will determine the robustness of each node and ultimately that of each configuration. The parameters that are used in the functions are

  18. Topology optimized RF MEMS switches

    DEFF Research Database (Denmark)

    Philippine, M. A.; Zareie, H.; Sigmund, Ole

    2013-01-01

    optimization for an RF MEM capacitive switch. Extensive experimental data confirms that the switches perform as designed by the optimizations, and that our simulation models are accurate. A subset of measurements are presented here. Broader results have been submitted in full journal format.......Topology optimization is a rigorous and powerful method that should become a standard MEMS design tool - it can produce unique and non-intuitive designs that meet complex objectives and can dramatically improve the performance and reliability of MEMS devices. We present successful uses of topology...

  19. Mobile Robot Navigation

    DEFF Research Database (Denmark)

    Andersen, Jens Christian

    2007-01-01

    Abstract Robots will soon take part in everyone’s daily life. In industrial production this has been the case for many years, but up to now the use of mobile robots has been limited to a few and isolated applications like lawn mowing, surveillance, agricultural production and military applications....... The research is now progressing towards autonomous robots which will be able to assist us in our daily life. One of the enabling technologies is navigation, and navigation is the subject of this thesis. Navigation of an autonomous robot is concerned with the ability of the robot to direct itself from...... validation of the implemented solutions and the ability of the methods to solve real world problems. The amount of software needed by an autonomous robot can be overwhelming. Software reuse and distributed development are therefore important issues. The thesis describes a new component architecture...

  20. Aerocapture navigation at Neptune

    Science.gov (United States)

    Haw, Robert J.

    2003-01-01

    A proposed Neptune orbiter Aerocapture mission will use solar electric propulsion to send an orbiter to Neptune. Navigation feasibility of direct-entry aerocapture for orbit insertion at Neptune is shown. The navigation strategy baselines optical imaging and (delta)VLBI measurement in order to satisfy the flight system's atmosphere entry flight path angle, which is targeted to enter Neptune with an entry flight path angle of -11.6 . Error bars on the entry flight path angle of plus/minus0.55 (3(sigma)) are proposed. This requirement can be satisfied with a data cutoff 3.2 days prior to arrival. There is some margin in the arrival template to tighten (i.e. reduce) the entry corridor either by scheduling a data cutoff closer to Neptune or alternatively, reducing uncertainties by increasing the fidelity of the optical navigation camera.

  1. Ion tracking in photocathode rf guns

    Directory of Open Access Journals (Sweden)

    John W. Lewellen

    2002-02-01

    Full Text Available Projected next-generation linac-based light sources, such as PERL or the TESLA free-electron laser, generally assume, as essential components of their injector complexes, long-pulse photocathode rf electron guns. These guns, due to their design rf pulse durations of many milliseconds to continuous wave, may be more susceptible to ion bombardment damage of their cathodes than conventional rf guns, which typically use rf pulses of microsecond duration. This paper explores this possibility in terms of ion propagation within the gun, and presents a basis for future study of the subject.

  2. RF front-end world class designs

    CERN Document Server

    Love, Janine

    2009-01-01

    All the design and development inspiration and direction a harware engineer needs in one blockbuster book! Janine Love site editor for RF Design Line,columnist, and author has selected the very best RF design material from the Newnes portfolio and has compiled it into this volume. The result is a book covering the gamut of RF front end design from antenna and filter design fundamentals to optimized layout techniques with a strong pragmatic emphasis. In addition to specific design techniques and practices, this book also discusses various approaches to solving RF front end design problems and h

  3. Navigation: Bat orientation using Earth's magnetic field

    DEFF Research Database (Denmark)

    Holland, Richard A.; Thorup, Kasper; Vonhof, Maarten J.

    2006-01-01

    Bats famously orientate at night by echolocation 1 , but this works over only a short range, and little is known about how they navigate over longer distances 2 . Here we show that the homing behaviour of Eptesicus fuscus, known as the big brown bat, can be altered by artificially shifting...... the Earth's magnetic field, indicating that these bats rely on a magnetic compass to return to their home roost. This finding adds to the impressive array of sensory abilities possessed by this animal for navigation in the dark....

  4. Novel H-type rf deflector

    Directory of Open Access Journals (Sweden)

    Yu. Senichev

    2006-01-01

    Full Text Available In this work we developed a new rf deflector based on the H resonator, which differs from previous ones in its design, the type of rf fundamental mode and the possibility of providing the π-mode standing wave for the beam in the deflection system. Because of the last aspect, the transverse shunt impedance of this deflector is much higher in comparison with its analogues. This idea was originally intended for application in the funneling system of the European Spallation Source, but we later found many additional applications, in particular, as the bunch separator after the electron and proton linear accelerators. We studied the beam dynamics and the electrodynamics and optimized the device parameters in the assumed range of frequency of 150–700 MHz for the proton beam and 1000–1500 MHz for the electron beam. To make the final choice we analyzed rf deflectors of different designs. We manufactured the experimental sample tested at the low rf power level.

  5. RF/optical shared aperture for high availability wideband communication RF/FSO links

    Science.gov (United States)

    Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

    2015-03-24

    An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

  6. RF Power Generation in LHC

    CERN Document Server

    Brunner, O C; Valuch, D

    2003-01-01

    The counter-rotating proton beams in the Large Hadron Collider (LHC) will be captured and then accelerated to their final energies of 2 x 7 TeV by two identical 400 MHz RF systems. The RF power source required for each beam comprises eight 300 kW klystrons. The output power of each klystron is fed via a circulator and a waveguide line to the input coupler of a single-cell super-conducting (SC) cavity. Four klystrons are powered by a 100 kV, 40A AC/DC power converter, previously used for the operation of the LEP klystrons. A five-gap thyratron crowbar protects the four klystrons in each of these units. The technical specification and measured performance of the various high-power elements are discussed. These include the 400MHz/300kW klystrons with emphasis on their group delay and the three-port circulators, which have to cope with peak reflected power levels up to twice the simultaneously applied incident power of 300 kW. In addition, a novel ferrite loaded waveguide absorber, used as termination for port No...

  7. SPS RF System Amplifier plant

    CERN Multimedia

    1977-01-01

    The picture shows a 2 MW, 200 MHz amplifier plant with feeder lines. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

  8. Improving Canada's Marine Navigation System through e-Navigation

    Directory of Open Access Journals (Sweden)

    Daniel Breton

    2016-06-01

    The conclusion proposed is that on-going work with key partners and stakeholders can be used as the primary mechanism to identify e-Navigation related innovation and needs, and to prioritize next steps. Moving forward in Canada, implementation of new e-navigation services will continue to be stakeholder driven, and used to drive improvements to Canada's marine navigation system.

  9. Navigating on handheld displays: Dynamic versus Static Keyhole Navigation

    NARCIS (Netherlands)

    Mehra, S.; Werkhoven, P.; Worring, M.

    2006-01-01

    Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A

  10. Navigation of robotic system using cricket motes

    Science.gov (United States)

    Patil, Yogendra J.; Baine, Nicholas A.; Rattan, Kuldip S.

    2011-06-01

    This paper presents a novel algorithm for self-mapping of the cricket motes that can be used for indoor navigation of autonomous robotic systems. The cricket system is a wireless sensor network that can provide indoor localization service to its user via acoustic ranging techniques. The behavior of the ultrasonic transducer on the cricket mote is studied and the regions where satisfactorily distance measurements can be obtained are recorded. Placing the motes in these regions results fine-grain mapping of the cricket motes. Trilateration is used to obtain a rigid coordinate system, but is insufficient if the network is to be used for navigation. A modified SLAM algorithm is applied to overcome the shortcomings of trilateration. Finally, the self-mapped cricket motes can be used for navigation of autonomous robotic systems in an indoor location.

  11. Ballistic Aspects of Feasibility for Prospective Satellite Navigation Technologies

    Directory of Open Access Journals (Sweden)

    L. N. Lysenko

    2015-01-01

    Full Text Available When modeling the operating processes of ballistics and navigation support it is expedient to make decomposition of the general problem of coordinate-time and navigation support into the typical options of its engineering implementation.As the satellite navigation technologies the paper considers inter-satellite measurement and autonomous navigation mode of differential correction. It also assesses the possibility of their application to improve the accuracy of navigation determinations.Technologies using inter-satellite measurement tools such as GLONASS / GPS equipment, equipment of inter-satellite radio link, astro-optical space based devices are an independent class of navigation technologies.However, each of these options has both advantages and disadvantages that affect the eva luation of the appropriateness and feasibility of their use.The paper separately considers the problem of increasing survivability of space systems and conservation of ground control complex due to introduction of requirements to ensure the independent functioning of spacecraft and application of technologies of ballistics and navigation support, supposing to involve minimum means of automated ground control complex for these purposes.Currently, there is a completely developed theory of autonomous navigation based on astronomical positional gauges, which are used as onboard optical sensors of orientation and stabilization systems.To date, the differential navigation mode is, virtually, the only approach that can allow the olution of tasks in terms of increased accuracy, but with some restrictions.The implementation of differential mode of treatment is carried out through the creation of differential subsystems of the satellite navigation systems. These subsystems are usually divided into wide-range, regional and local ones.Analysis of ballistic aspects to implement discussed navigation technologies allowed us to identify constraints for improving accuracy to define

  12. Navigation Architecture for a Space Mobile Network

    Science.gov (United States)

    Valdez, Jennifer E.; Ashman, Benjamin; Gramling, Cheryl; Heckler, Gregory W.; Carpenter, Russell

    2016-01-01

    The Tracking and Data Relay Satellite System (TDRSS) Augmentation Service for Satellites (TASS) is a proposed beacon service to provide a global, space based GPS augmentation service based on the NASA Global Differential GPS (GDGPS) System. The TASS signal will be tied to the GPS time system and usable as an additional ranging and Doppler radiometric source. Additionally, it will provide data vital to autonomous navigation in the near Earth regime, including space weather information, TDRS ephemerides, Earth Orientation Parameters (EOP), and forward commanding capability. TASS benefits include enhancing situational awareness, enabling increased autonomy, and providing near real-time command access for user platforms. As NASA Headquarters' Space Communication and Navigation Office (SCaN) begins to move away from a centralized network architecture and towards a Space Mobile Network (SMN) that allows for user initiated services, autonomous navigation will be a key part of such a system. This paper explores how a TASS beacon service enables the Space Mobile Networking paradigm, what a typical user platform would require, and provides an in-depth analysis of several navigation scenarios and operations concepts. This paper provides an overview of the TASS beacon and its role within the SMN and user community. Supporting navigation analysis is presented for two user mission scenarios: an Earth observing spacecraft in low earth orbit (LEO), and a highly elliptical spacecraft in a lunar resonance orbit. These diverse flight scenarios indicate the breadth of applicability of the TASS beacon for upcoming users within the current network architecture and in the SMN.

  13. Crew-Aided Autonomous Navigation

    Science.gov (United States)

    Holt, Greg N.

    2015-01-01

    A sextant provides manual capability to perform star/planet-limb sightings and offers a cheap, simple, robust backup navigation source for exploration missions independent from the ground. Sextant sightings from spacecraft were first exercised in Gemini and flew as the lost-communication backup for all Apollo missions. This study characterized error sources of navigation-grade sextants for feasibility of taking star and planetary limb sightings from inside a spacecraft. A series of similar studies was performed in the early/mid-1960s in preparation for Apollo missions. This study modernized and updated those findings in addition to showing feasibility using Linear Covariance analysis techniques. The human eyeball is a remarkable piece of optical equipment and provides many advantages over camera-based systems, including dynamic range and detail resolution. This technique utilizes those advantages and provides important autonomy to the crew in the event of lost communication with the ground. It can also provide confidence and verification of low-TRL automated onboard systems. The technique is extremely flexible and is not dependent on any particular vehicle type. The investigation involved procuring navigation-grade sextants and characterizing their performance under a variety of conditions encountered in exploration missions. The JSC optical sensor lab and Orion mockup were the primary testing locations. For the accuracy assessment, a group of test subjects took sextant readings on calibrated targets while instrument/operator precision was measured. The study demonstrated repeatability of star/planet-limb sightings with bias and standard deviation around 10 arcseconds, then used high-fidelity simulations to verify those accuracy levels met the needs for targeting mid-course maneuvers in preparation for Earth reen.

  14. Comparison of Measured and Calculated Coupling between a Waveguide and an RF Cavity Using CST Microwave Studio

    Energy Technology Data Exchange (ETDEWEB)

    J. Shi; H. Chen; S. Zheng; D. Li; R.A. Rimmer; H. Wang

    2006-06-26

    Accurate predications of RF coupling between an RF cavity and ports attached to it have been an important study subject for years for RF coupler and higher order modes (HOM) damping design. We report recent progress and a method on the RF coupling simulations between waveguide ports and RF cavities using CST Microwave Studio in time domain (Transit Solver). Comparisons of the measured and calculated couplings are presented. The simulated couplings and frequencies agree within {approx} 10% and {approx} 0.1% with the measurements, respectively. We have simulated couplings with external Qs ranging from {approx} 100 to {approx} 100,000, and confirmed with measurements. The method should also work well for higher Qs, and can be easily applied in RF power coupler designs and HOM damping for normal-conducting and superconducting cavities.

  15. Inland Electronic Navigational Charts (IENC)

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — These Inland Electronic Navigational Charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  16. Rf Gun with High-Current Density Field Emission Cathode

    Energy Technology Data Exchange (ETDEWEB)

    Jay L. Hirshfield

    2005-12-19

    High current-density field emission from an array of carbon nanotubes, with field-emission-transistor control, and with secondary electron channel multiplication in a ceramic facing structure, have been combined in a cold cathode for rf guns and diode guns. Electrodynamic and space-charge flow simulations were conducted to specify the cathode configuration and range of emission current density from the field emission cold cathode. Design of this cathode has been made for installation and testing in an existing S-band 2-1/2 cell rf gun. With emission control and modulation, and with current density in the range of 0.1-1 kA/cm2, this cathode could provide performance and long-life not enjoyed by other currently-available cathodes

  17. CNES - Chalmers - IAP - ONERA - XLIM activities in the domain of high RF power breakdown phenomena

    Science.gov (United States)

    Puech, J.; Sorolla, E.; Semenov, V. E.; Rakova, E. I.; Anderson, D.; Belhaj, M.; Hillairet, J.

    2017-10-01

    Multipactor breakdown is an important potential failure mechanism in many different microwave devices working under close to vacuum conditions. Applications range from space borne RF equipment to high-power microwave generators. The basic physics involved in the multipactor phenomenon is well known for the case of two infinite pallel plates made of metal. However, most realistic RF device geometries involve inhomogeneous RF electric fields and curved field lines and sometimes also dielectric material. The purpose of this paper is to set up methodologies to determine the Multipactor threshold in such situations.

  18. Navigating in higher education

    DEFF Research Database (Denmark)

    Thingholm, Hanne Balsby; Reimer, David; Keiding, Tina Bering

    Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur...

  19. Navigating between the Dimensions

    Science.gov (United States)

    Fleron, Julian F.; Ecke, Volker

    2011-01-01

    Generations have been inspired by Edwin A. Abbott's profound tour of the dimensions in his novella "Flatland: A Romance of Many Dimensions" (1884). This well-known satire is the story of a flat land inhabited by geometric shapes trying to navigate the subtleties of their geometric, social, and political positions. In this article, the authors…

  20. Navigating ‘riskscapes’

    DEFF Research Database (Denmark)

    Gee, Stephanie; Skovdal, Morten

    2017-01-01

    This paper draws on interview data to examine how international health care workers navigated risk during the unprecedented Ebola outbreak in West Africa. It identifies the importance of place in risk perception, including how different spatial localities give rise to different feelings of threat...

  1. Astronomy and Navigation

    Science.gov (United States)

    Pimenta, Fernando

    Different people, seafaring in different parts of the world, used strategies well adapted to their environment with the purpose of safely reaching their destination. Astronomical elements, present in their navigation "toolkit" for orientation, calendar purposes, and time reckoning, contributed to their conceptualization of space and time and were eventually integrated in their ritual, social organization, and social power structure.

  2. Landmark-based pedestrian navigation

    OpenAIRE

    Basiri, Anahid; Winstanley, Adam; Amirian, Pouria

    2013-01-01

    Car navigation has become one of the most widely used examples of Location-Based Services (LBSs). However current car navigation systems are not fully suitable for the navigational needs of pedestrians mainly because walkers are not as restricted as car drivers. Pedestrians can easily go into a building or underground to get to their destination where GPS signals are unavailable. Seamless indoor and outdoor navigation is one of the most important features which should be handle...

  3. Simulation of plasma loading of high-pressure RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Kwangmin [Brookhaven; Samulyak, Roman [SUNY, Stony Brook; Yonehara, Katsuya [Fermilab; Freemire, Ben [Northern Illinois U.

    2018-01-11

    Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have been performed in the range of parameters typical for practical muon cooling channels.

  4. Substrate noise coupling in analog/RF circuits

    CERN Document Server

    Bronckers, Stephane; Vandersteen, Gerd; Rolain, Yves

    2010-01-01

    This practical resource offers you detailed guidance on the impact of substrate noise on a wide range of circuits operating from baseband frequencies up to mm-wave frequencies. This unique book presents case studies to illustrate that careful modeling of the assembly characteristics and layout details is required to bring simulations and measurements into agreement. You learn how to use a proper combination of isolation structures and circuit techniques to make analog/RF circuits more immune to substrate noise.

  5. Pilot stereotypes for navigation symbols on electronic displays

    Science.gov (United States)

    2006-09-20

    There is currently no common symbology standard for the : electronic display of navigation information. The wide : range of display technologies and the different functions : these displays support make it difficult to design symbols : that are easil...

  6. Coastal Piloting & Charting: Navigation 101.

    Science.gov (United States)

    Osinski, Alison

    This curriculum guide for a beginning course on marine navigation describes marine navigation (the art of and science of determining position of a ship and its movement from one position to another in order to keep track of where the ship is and where it is going) and defines dead reckoning, piloting, electronic navigation, and celestial…

  7. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    Science.gov (United States)

    Norem, James H.; Pellin, Michael J.

    2013-06-11

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  8. Unexpected reduction of rf spin resonance strength for stored deuteron beams

    Directory of Open Access Journals (Sweden)

    A. D. Krisch

    2007-07-01

    Full Text Available Stored beams of polarized protons, electrons, or deuterons can be spin flipped by sweeping an rf dipole’s or solenoid’s frequency through an rf spin resonance. Fitting such data to the modified Froissart-Stora equation’s spin resonance strength E_{FS} gave very large deviations from the ^{*}E_{Bdl} obtained from each rf magnet’s ∫B_{rms}dl. We recently varied an rf dipole’s frequency sweep range Δf, and the momentum spread Δp/p and betatron tune ν_{y} of stored 1.85  GeV/c polarized deuterons. We found a sharp constructive interference when ν_{y} was near an intrinsic spin resonance. Moreover, over large Δf and Δp/p ranges, E_{FS} was about 7 times smaller than the predicted ^{*}E_{Bdl}.

  9. LTE RF subsystem power consumption modeling

    DEFF Research Database (Denmark)

    Musiige, Deogratius; Vincent, Laulagnet; Anton, François

    2012-01-01

    This paper presents a new power consumption emulation model, for all possible scenarios of the RF subsystem, when transmitting a LTE signal. The model takes the logical interface parameters, Tx power, carrier frequency and bandwidth between the baseband and RF subsystem as inputs to compute...

  10. 47 CFR 101.1525 - RF safety.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false RF safety. 101.1525 Section 101.1525 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Service and Technical Rules for the 70/80/90 GHz Bands § 101.1525 RF safety. Licensees in the 70...

  11. 47 CFR 27.52 - RF safety.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false RF safety. 27.52 Section 27.52 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.52 RF safety. Licensees and manufacturers are subject to the...

  12. 47 CFR 90.1335 - RF safety.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false RF safety. 90.1335 Section 90.1335 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Wireless Broadband Services in the 3650-3700 MHz Band § 90.1335 RF safety...

  13. 47 CFR 95.1125 - RF safety.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false RF safety. 95.1125 Section 95.1125 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Wireless Medical Telemetry Service (WMTS) General Provisions § 95.1125 RF safety. Portable devices...

  14. 17th International Conference on RF Superconductivity

    CERN Document Server

    Laxdal, Robert E.; Schaa, Volker R.W.

    2015-01-01

    RF superconductivity is the key technology of accelerators for particle physics, nuclear physics and light sources. SRF 2015 covered the latest advances in the science, technology, and applications of superconducting RF. There was also an industrial exhibit during the conference with the key vendors in the community available to discuss their capabilities and products.

  15. Electrowetting-actuated liquid metal for RF applications

    Science.gov (United States)

    Diebold, A. V.; Watson, A. M.; Holcomb, S.; Tabor, C.; Mast, D.; Dickey, M. D.; Heikenfeld, J.

    2017-02-01

    Electrowetting is well-established as a fluid manipulation technique in such areas as lab-on-a-chip, visible light optics, and displays, yet has seen far less implementation in the field of radio-frequency (RF) electronics and electromagnetics. This is primarily due to a lack of appropriate materials selection and control in these devices. Low loss RF conductive fluids such as room temperature liquid metals (i.e. Hg, EGaIn, Galinstan) are by far the leading choice of active material due to their superior electrical properties but require high actuating voltages due to their inherently high surface tensions (>400 mN m-1) which often lead to dielectric breakdown. While the toxicity of Hg encourages the pursuit of non-toxic alternatives such as gallium alloys, the native surface oxide formation often prohibits reliable device functionality. Additionally, traditional electrowetting architectures rely on lossy electrode materials which degrade RF transmission efficiencies and result in non-reversible material diffusion at the electrode/liquid metal contact. In this work, we report on approaches to utilize liquid metals in electrowetting on dielectric (EWOD) devices that resolve all of these challenges by judicious choice of novel electrode materials, dielectric fluid, and device architecture. A functional RF device, namely an electromagnetic polarizer, is demonstrated that can be activated on demand through EWOD and provides an average signal attenuation of 12.91 dB in the on state and 1.46 dB in the off state over the range of 8-9.2 GHz, with a switching speed of about 12 ms. These results can be further extended to other RF applications such as tunable antennas, transmission lines, and switchable metasurfaces.

  16. RF power generation for future linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fowkes, W.R.; Allen, M.A.; Callin, R.S.; Caryotakis, G.; Eppley, K.R.; Fant, K.S.; Farkas, Z.D.; Feinstein, J.; Ko, K.; Koontz, R.F.; Kroll, N.; Lavine, T.L.; Lee, T.G.; Miller, R.H.; Pearson, C.; Spalek, G.; Vlieks, A.E.; Wilson, P.B.

    1990-06-01

    The next linear collider will require 200 MW of rf power per meter of linac structure at relatively high frequency to produce an accelerating gradient of about 100 MV/m. The higher frequencies result in a higher breakdown threshold in the accelerating structure hence permit higher accelerating gradients per meter of linac. The lower frequencies have the advantage that high peak power rf sources can be realized. 11.42 GHz appears to be a good compromise and the effort at the Stanford Linear Accelerator Center (SLAC) is being concentrated on rf sources operating at this frequency. The filling time of the accelerating structure for each rf feed is expected to be about 80 ns. Under serious consideration at SLAC is a conventional klystron followed by a multistage rf pulse compression system, and the Crossed-Field Amplifier. These are discussed in this paper.

  17. RF Transceiver Design for MIMO Wireless Communications

    CERN Document Server

    Mohammadi, Abbas

    2012-01-01

    This practical resource offers a thorough examination of RF transceiver design for MIMO communications.  Offering a practical view on MIMO wireless systems, this book extends fundamental concepts on classic wireless transceiver design techniques to MIMO transceivers. This helps reader gain a very comprehensive understanding of the subject. This in-depth volume describes many theoretical and implementation challenges on MIMO transceivers and provides the practical solutions for these issues. This comprehensive book provides thorough descriptions of MIMO theoretical concepts, MIMO single carrier and OFDM modulation, RF transceiver design concepts, power amplifier, MIMO transmitter design techniques and their RF impairments, MIMO receiver design methods, RF impairments study including nonlinearity, DC-offset, I/Q imbalance and phase noise and their compensation in OFDM and MIMO techniques. In addition, it provides the most practical techniques to realize RF front-ends in MIMO systems. This book is supported wit...

  18. Control algorithms for autonomous robot navigation

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, C.C.

    1985-09-20

    This paper examines control algorithm requirements for autonomous robot navigation outside laboratory environments. Three aspects of navigation are considered: navigation control in explored terrain, environment interactions with robot sensors, and navigation control in unanticipated situations. Major navigation methods are presented and relevance of traditional human learning theory is discussed. A new navigation technique linking graph theory and incidental learning is introduced.

  19. Femtosecond precision measurement of laser–rf phase jitter in a photocathode rf gun

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Libing; Zhao, Lingrong; Lu, Chao; Jiang, Tao; Liu, Shengguang; Wang, Rui; Zhu, Pengfei; Xiang, Dao, E-mail: dxiang@sjtu.edu.cn

    2017-03-21

    We report on the measurement of the laser–rf phase jitter in a photocathode rf gun with femtosecond precision. In this experiment four laser pulses with equal separation are used to produce electron bunch trains; then the laser–rf phase jitter is obtained by measuring the variations of the electron bunch spacing with an rf deflector. Furthermore, we show that when the gun and the deflector are powered by the same rf source, it is possible to obtain the laser–rf phase jitter in the gun through measurement of the beam–rf phase jitter in the deflector. Based on these measurements, we propose an effective time-stamping method that may be applied in MeV ultrafast electron diffraction facilities to enhance the temporal resolution.

  20. New Driver For The Powerful Output Rf Amplifier Of Mmf Dtl Rf System

    CERN Document Server

    Kvasha, A I; Vassilyev, A G

    2004-01-01

    More than 30 years ago a few powerful vacuum tubes were specially designed and produced in the former design office Swetlana for the Moscow meson factory DTL RF system. Among them was tetrode GI-51A with output pulse RF power up to 300 kW at frequency 198.2 MHz, which was used as driver for RF power amplifier with output RF pulse power (2-3) MW. In connection with well-known events in our country manufacture of these tubes, including GI-51A was finished about 10 years ago. In "SED-SPb" (successor of the design office Swetlana) triode GI-57A was offered instead of GI-51A. In this paper results of calculations and design of RF amplifier with new triode are presented. Preliminary results of RF amplifier tests, also presented in the paper, showed that triode GI-57A will be able successfully used in the DTL RF system channels.

  1. RF compensation of single Langmuir probe in low density helicon plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Soumen, E-mail: soumen@ipr.res.in; Chattopadhyay, Prabal K.; Ghosh, Joydeep; Bora, Dhiraj

    2016-11-15

    Highlights: • Appropriate density and temperature measurement with Langmuir probe in RF Eenvironment. • Necessity of large auxiliary electrode for RF compensation at low densities (∼10{sup 16} m{sup −3}). • Measured two temperature electrons in low pressure helicon antenna produced RF plasma. • Tail electrons are localized only at off-axis in our cylindrical plasma system. - Abstract: Interpretations of Single Langmuir probe measurements in electrode-less radio frequency (RF) plasmas are noteworthy tricky and require adequate compensation of RF. Conventional RF compensation technique is limited only at high density (>10{sup 17} m{sup −3}) RF plasmas. RF compensation of single Langmuir probe at low density RF plasmas (∼10{sup 16} m{sup −3}) is presented in this paper. In RF driven plasmas, where the RF voltage is high (∼50 V) and density is in the range (∼10{sup 16} m{sup −3}), the primary RF compensation condition (Z{sub ck} > >Z{sub sh}) is very difficult to fulfill, because of high sheath impedance (Z{sub sh}) at 13.56 MHz and the construction limitation of a self-resonant tiny chock (Z{sub ck}) with very high impedance. Introducing a large auxiliary electrode (A{sub x}), (A{sub x} >>> A{sub p}), close to the small Langmuir probe (A{sub p}) tip, connected in parallel with probe via a coupling capacitor (C{sub cp}), significantly reduces the effective sheath impedance (Z{sub sh}) and allows probe bias to follow the RF oscillation. Dimensional requirements of the auxiliary electrode and the role of suitable coupling capacitor are discussed in this paper. Observations show proper compensation leads to estimation of more positive floating potentials and lower electron temperatures compared to uncompensated probe. The electron energy probability function (EEPF) is also obtained by double differentiating the collected current with respect to the applied bias voltage using an active analog circuit.

  2. RF low power subsampling architecture for wireless communication applications

    National Research Council Canada - National Science Library

    Meng, Fanzhen; Liu, Hong; Wang, Mingliang; Zhang, Xiaolin; Tian, Tong

    2016-01-01

    ...) transmission devices, especially the RF receiver. In order to alleviate this problem, an RF low power subsampling architecture for wireless communication applications is proposed in this paper...

  3. Navigating Distributed Services

    DEFF Research Database (Denmark)

    Beute, Berco

    2002-01-01

    This thesis explores the impact of three current trends which, when taken together, arefundamentally changing the way in which the task of navigating virtual environmentsis accomplished. The first concerns the changeover from a situation in which all dataand functionality reside locally to the user......, to a situation where they are distributedacross the Internet. The second trend is the shift from a virtual environment that solelyconsists of distributed documents to a virtual environment that consists of bothdistributed documents and distributed services. The third and final trend is theincreasing diversity...... of devices used to access information on the Internet.The focal point of the thesis is an initial exploration of the effects of the trends onusers as they navigate the virtual environment of distributed documents and services.To begin the thesis uses scenarios as a heuristic device to identify and analyse...

  4. An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.

    Science.gov (United States)

    Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo

    2017-03-25

    Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.

  5. Phase noise in RF and microwave amplifiers.

    Science.gov (United States)

    Boudot, Rodolphe; Rubiola, Enrico

    2012-12-01

    Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase φ(t) is Sφ(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and

  6. Use of Real‐Time GNSS‐RF Data to Characterize the Swing Movements of Forestry Equipment

    OpenAIRE

    Ryer M. Becker; Robert F. Keefe; Anderson, Nathaniel M

    2017-01-01

    The western United States faces significant forest management challenges after severe bark beetle infestations have led to substantial mortality. Minimizing costs is vital for increasing the feasibility of management operations in affected forests. Multi‐transmitter Global Navigation Satellite System (GNSS)‐radio frequencies (RF) technology has applications in the quantification and analysis of harvest system production efficiency and provision of real‐time operational machine position, navi...

  7. Navigation in virtual environments

    Science.gov (United States)

    Arthur, Erik; Hancock, Peter A.; Telke, Susan

    1996-06-01

    Virtual environments show great promise in the area of training. ALthough such synthetic environments project homeomorphic physical representations of real- world layouts, it is not known how individuals develop models to match such environments. To evaluate this process, the present experiment examined the accuracy of triadic representations of objects having learned them previously under different conditions. The layout consisted of four different colored spheres arranged on a flat plane. These objects could be viewed in either a free navigation virtual environment condition (NAV) or a single body position virtual environment condition. The first condition allowed active exploration of the environment while the latter condition allowed the participant only a passive opportunity to observe form a single viewpoint. These viewing conditions were a between-subject variable with ten participants randomly assigned to each condition. Performance was assessed by the response latency to judge the accuracy of a layout of three objects over different rotations. Results showed linear increases in response latency as the rotation angle increased from the initial perspective in SBP condition. The NAV condition did not show a similar effect of rotation angle. These results suggest that the spatial knowledge acquisition from virtual environments through navigation is similar to actual navigation.

  8. The attack navigator

    DEFF Research Database (Denmark)

    Probst, Christian W.; Willemson, Jan; Pieters, Wolter

    2016-01-01

    The need to assess security and take protection decisions is at least as old as our civilisation. However, the complexity and development speed of our interconnected technical systems have surpassed our capacity to imagine and evaluate risk scenarios. This holds in particular for risks that are c......The need to assess security and take protection decisions is at least as old as our civilisation. However, the complexity and development speed of our interconnected technical systems have surpassed our capacity to imagine and evaluate risk scenarios. This holds in particular for risks...... that are caused by the strategic behaviour of adversaries. Therefore, technology-supported methods are needed to help us identify and manage these risks. In this paper, we describe the attack navigator: a graph-based approach to security risk assessment inspired by navigation systems. Based on maps of a socio......-technical system, the attack navigator identifies routes to an attacker goal. Specific attacker properties such as skill or resources can be included through attacker profiles. This enables defenders to explore attack scenarios and the effectiveness of defense alternatives under different threat conditions....

  9. Assessment of DSM-5 Section II Personality Disorders With the MMPI-2-RF in a Nonclinical Sample.

    Science.gov (United States)

    Sellbom, Martin; Smith, Alexander

    2017-01-01

    The Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008 / 2011 ) is frequently used in clinical practice. However, there has been a dearth of literature on how well this instrument can assess symptoms associated with personality disorders (PDs). This investigation examined a range of hypothesized MMPI-2-RF scales in predicting PD symptoms. We evaluated these associations in a sample of 397 university students who had been administered the MMPI-2-RF and the Structured Clinical Interview for DSM-IV Axis II Disorders-Personality Questionnaire (First, Gibbon, Spitzer, Williams, & Benjamin, 1997 ). Zero-order correlation analyses and negative binomial regression models indicated that a wide range of MMPI-2-RF scale hypotheses were supported; however, the least support was available for predicting schizoid and obsessive-compulsive PDs. Implications for MMPI-2-RF interpretation and PD diagnosis are discussed.

  10. 33 CFR 334.1120 - Pacific Ocean in the vicinity of Point Mugu, Calif.; naval small arms firing range.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Pacific Ocean in the vicinity of Point Mugu, Calif.; naval small arms firing range. 334.1120 Section 334.1120 Navigation and Navigable... REGULATIONS § 334.1120 Pacific Ocean in the vicinity of Point Mugu, Calif.; naval small arms firing range. (a...

  11. 33 CFR 334.650 - Gulf of Mexico, south of St. George Island, Fla.; test firing range.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Gulf of Mexico, south of St. George Island, Fla.; test firing range. 334.650 Section 334.650 Navigation and Navigable Waters CORPS OF....650 Gulf of Mexico, south of St. George Island, Fla.; test firing range. (a) The danger zone. A fan...

  12. A State-of-the-Art Survey of Indoor Positioning and Navigation Systems and Technologies

    Directory of Open Access Journals (Sweden)

    Wilson Sakpere

    2017-12-01

    Full Text Available The research and use of positioning and navigation technologies outdoors has seen a steady and exponential growth. Based on this success, there have been attempts to implement these technologies indoors, leading to numerous studies. Most of the algorithms, techniques and technologies used have been implemented outdoors. However, how they fare indoors is different altogether. Thus, several technologies have been proposed and implemented to improve positioning and navigation indoors. Among them are Infrared (IR, Ultrasound, Audible Sound, Magnetic, Optical and Vision, Radio Frequency (RF, Visible Light, Pedestrian Dead Reckoning (PDR/Inertial Navigation System (INS and Hybrid. The RF technologies include Bluetooth, Ultra-wideband (UWB, Wireless Sensor Network (WSN, Wireless Local Area Network (WLAN, Radio-Frequency Identification (RFID and Near Field Communication (NFC. In addition, positioning techniques applied in indoor positioning systems include the signal properties and positioning algorithms. The prevalent signal properties are Angle of Arrival (AOA, Time of Arrival (TOA, Time Difference of Arrival (TDOA and Received Signal Strength Indication (RSSI, while the positioning algorithms are Triangulation, Trilateration, Proximity and Scene Analysis/ Fingerprinting. This paper presents a state-of-the-art survey of indoor positioning and navigation systems and technologies, and their use in various scenarios. It analyses distinct positioning technology metrics such as accuracy, complexity, cost, privacy, scalability and usability. This paper has profound implications for future studies of positioning and navigation.

  13. Physical and Chemical Characterization of the UCLA RF Plasma Dissociator

    Science.gov (United States)

    Zwi, Helio R.; Huhn, William; Lynn, Alexander W.; Wong, Alfred Y.

    1996-11-01

    The UCLA RF Plasma Dissociator is an inductively coupled plasma device, developed for the dissociation of simulated hazardous waste with either inert (Argon) or oxidizing (air) carrier gases at atmospheric pressure. The rf coil (15 cm length, 8.9 cm diameter) operates at 2.85 MHz with power ranging from 40 to 85 kW. Plasma temperature and density have been measured with emission spectrometry, infrared interferometry and shielded probes. Electron temperatures (0.4---1.2 eV) are usually higher than ion and neutral temperatures. Very high dissociation efficiencies for CCl4 and CF_2Cl2 heve been demonstrated with gas chromatography/mass spectrometry (GC/MS) and other chemical procedures.

  14. Cold cathode rf guns based study on field emission

    Directory of Open Access Journals (Sweden)

    Xiangkun Li

    2013-12-01

    Full Text Available Recently cold cathodes based on field emission have drawn attention and been considered to drive accelerators and free electron lasers, due to the progress in field emitter arrays and planar emitters like diamond films. In this paper, we reviewed the characteristics of field emission in rf fields. Simulations of S-band rf guns consisting of a cathode cell and a full cell were done. We showed that a shorter cathode cell with a length of 0.25–0.3 of λ/2 is in favor of obtaining both low emittance and low energy spread bunches when the amplitude of electric field on the cathode surface ranges from 60 to 80  MV/m. A single cell test cavity has been installed to study field emission of diamond films and the measured beam current showed a good agreement with theoretical calculations.

  15. Principles of goal-directed spatial robot navigation in biomimetic models.

    Science.gov (United States)

    Milford, Michael; Schulz, Ruth

    2014-11-05

    Mobile robots and animals alike must effectively navigate their environments in order to achieve their goals. For animals goal-directed navigation facilitates finding food, seeking shelter or migration; similarly robots perform goal-directed navigation to find a charging station, get out of the rain or guide a person to a destination. This similarity in tasks extends to the environment as well; increasingly, mobile robots are operating in the same underwater, ground and aerial environments that animals do. Yet despite these similarities, goal-directed navigation research in robotics and biology has proceeded largely in parallel, linked only by a small amount of interdisciplinary research spanning both areas. Most state-of-the-art robotic navigation systems employ a range of sensors, world representations and navigation algorithms that seem far removed from what we know of how animals navigate; their navigation systems are shaped by key principles of navigation in 'real-world' environments including dealing with uncertainty in sensing, landmark observation and world modelling. By contrast, biomimetic animal navigation models produce plausible animal navigation behaviour in a range of laboratory experimental navigation paradigms, typically without addressing many of these robotic navigation principles. In this paper, we attempt to link robotics and biology by reviewing the current state of the art in conventional and biomimetic goal-directed navigation models, focusing on the key principles of goal-oriented robotic navigation and the extent to which these principles have been adapted by biomimetic navigation models and why. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  16. Radio-Frequency (rf) Confinement in Ion Mobility Spectrometry: Apparent Mobilities and Effective Temperatures.

    Science.gov (United States)

    Allen, Samuel J; Bush, Matthew F

    2016-12-01

    Ion mobility is a powerful tool for separating and characterizing the structures of ions. Here, a radio-frequency (rf) confining drift cell is used to evaluate the drift times of ions over a broad range of drift field strengths (E/P, V cm(-1) Torr(-1)). The presence of rf potentials radially confines ions and results in excellent ion transmission at low E/P (less than 1 V cm(-1) Torr(-1)), thereby reducing the dependence of ion transmission on the applied drift voltage. Non-linear responses between drift time and reciprocal drift voltages are observed for extremely low E/P and high rf amplitudes. Under these conditions, pseudopotential wells generated by the rf potentials dampen the mobility of ions. The effective potential approximation is used to characterize this mobility dampening behavior, which can be mitigated by adjusting rf amplitudes and electrode dimensions. Using SIMION trajectories and statistical arguments, the effective temperatures of ions in an rf-confining drift cell are evaluated. Results for the doubly charged peptide GRGDS suggest that applied rf potentials can result in a subtle increase (2 K) in effective temperature compared to an electrostatic drift tube. Additionally, simulations of native-like ions of the protein complex avidin suggest that rf potentials have a negligible effect on the effective temperature of these ions. In general, the results of this study suggest that applied rf potentials enable the measurement of drift times at extremely low E/P and that these potentials have negligible effects on ion effective temperature. Graphical Abstract ᅟ.

  17. Nb-Pb superconducting RF-gun

    Energy Technology Data Exchange (ETDEWEB)

    Sekutowicz, J.; Iversen, J.; Kreps, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (DE)] (and others)

    2005-07-01

    We report on the status of an electron RF-gun made of two superconductors: niobium and lead. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead, as compared to other superconducting metals. The concept, mentioned in a previous paper, follows the attractive approach of all niobium superconducting RF-gun as it has been proposed by the BNL group. Measured values of quantum efficiency for lead at various photon energies, analysis of recombination time of photon-broken Cooper pairs for lead and niobium, and preliminary cold test results are discussed in this paper. (orig.)

  18. Nb-Pb superconducting RF gun

    Energy Technology Data Exchange (ETDEWEB)

    J. Sekutowicz; J. Iversen; G. Kreps; W.D. Moller; W. Singer; X. Singer; I. Ben-Zvi; A. Burrill; J. Smedley; T. Rao; M. Ferrario; P. Kneisel; J. Langner; P. Strzyzewski; R. Lefferts; A. Lipski; K. Szalowski; K. Ko; L. Xiao

    2006-04-14

    We report on the status of an electron RF-gun made of two superconductors: niobium and lead. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead, as compared to other superconducting metals. The concept, mentioned in a previous paper, follows the attractive approach of all niobium superconducting RF-gun as it has been proposed by the BNL group. Measured values of quantum efficiency for lead at various photon energies, analysis of recombination time of photon-broken Cooper pairs for lead and niobium, and preliminary cold test results are discussed in this paper.

  19. Nb-Pb Superconducting RF Gun

    Energy Technology Data Exchange (ETDEWEB)

    Sekutowicz, J.; Iversen, J.; Kreps, G.; Moller, W.D.; Singer, W.; Singer, X.; /DESY; Ben-Zvi, I.; Burrill, A.; Smedley, J.; Rao, T.; /Brookhaven; Ferrario, M.; /Frascati; Kneisel, P.; /Jefferson Lab; Langner, J.; Strzyzewski, P.; /Warsaw, Inst. Nucl. Studies; Lefferts, R.; Lipski, A.; /SUNY, Stony Brook; Szalowski, K.; /Lodz U.; Ko, K.; Xiao, L.; /SLAC

    2006-03-29

    We report on the status of an electron RF-gun made of two superconductors: niobium and lead. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead, as compared to other superconducting metals. The concept, mentioned in a previous paper, follows the attractive approach of all niobium superconducting RF-gun as it has been proposed by the BNL group. Measured values of quantum efficiency for lead at various photon energies, analysis of recombination time of photon-broken Cooper pairs for lead and niobium, and preliminary cold test results are discussed in this paper.

  20. Practical guide to RF-MEMS

    CERN Document Server

    Iannacci, Jacopo

    2013-01-01

    Closes the gap between hardcore-theoretical and purely experimental RF-MEMS books. The book covers, from a practical viewpoint, the most critical steps that have to be taken in order to develop novel RF-MEMS device concepts. Prototypical RF-MEMS devices, both including lumped components and complex networks, are presented at the beginning of the book as reference examples, and these are then discussed from different perspectives with regard to design, simulation, packaging, testing, and post-fabrication modeling. Theoretical concepts are introduced when necessary to complement the practical

  1. RF engineering basic concepts: S-parameters

    CERN Document Server

    Caspers, F

    2011-01-01

    The concept of describing RF circuits in terms of waves is discussed and the S-matrix and related matrices are defined. The signal flow graph (SFG) is introduced as a graphical means to visualize how waves propagate in an RF network. The properties of the most relevant passive RF devices (hybrids, couplers, non-reciprocal elements, etc.) are delineated and the corresponding S-parameters are given. For microwave integrated circuits (MICs) planar transmission lines such as the microstrip line have become very important.

  2. Lower Power Design for UHF RF CMOS Circuits Based on the Power Consumption Acuity

    Directory of Open Access Journals (Sweden)

    Niu Xiang-jie

    2014-01-01

    Full Text Available Excessive energy consumption of UHF tag is the bottleneck of energy saving in its wide range of applications. To address this issue, a lower power design for UHF RF CMOS circuits based on power consumption acuity is proposed in this paper. Through in-depth analysis of the static and dynamic power generation principle of UHF RF circuits in the work, the power consumption acuity can be calculated by using the correlation of circuit power and input vector. Subsequently, under the guide of this acuity, the UHF RF CMOS circuits with better energy saving can be designed. Furthermore, according to the performance indicators of EPC CIG2 UHF RFID in UHF identification, the corresponding circuit is designed and implemented. The test results show that the design of UHF RF circuit based on the acuity of power consumption can reduce 35%–40% power consumption.

  3. RF up/down-conversion based on optically injection-locked VCSEL.

    Science.gov (United States)

    Guo, Peng; Zhang, Cheng; Xu, Anshi; Chen, Zhangyuan

    2013-03-25

    All-optical radio frequency conversion is proposed by directly modulated optically injection-locked vertical-cavity surface-emitting lasers. The enhancement effect of second order products of RF signals by OIL technique is analyzed based on reflection-mode OIL model. Simulation results show that high injection ratio and large wavelength detuning of OIL condition lead to a high RF conversion gain. Compared with free running condition, more than 20 dB RF conversion gain enhancement is achieved in the simulation. The experimental results of the RF conversion gain improvement (+ 18 dB) by OIL show excellent agreement with our simulation results. The spurious free dynamic range improvement (+ 15 dB) of conversion signals by OIL is also experimentally demonstrated.

  4. Is navigation in virtual reality with FMRI really navigation?

    Science.gov (United States)

    Taube, Jeffrey S; Valerio, Stephane; Yoder, Ryan M

    2013-07-01

    Identifying the neural mechanisms underlying spatial orientation and navigation has long posed a challenge for researchers. Multiple approaches incorporating a variety of techniques and animal models have been used to address this issue. More recently, virtual navigation has become a popular tool for understanding navigational processes. Although combining this technique with functional imaging can provide important information on many aspects of spatial navigation, it is important to recognize some of the limitations these techniques have for gaining a complete understanding of the neural mechanisms of navigation. Foremost among these is that, when participants perform a virtual navigation task in a scanner, they are lying motionless in a supine position while viewing a video monitor. Here, we provide evidence that spatial orientation and navigation rely to a large extent on locomotion and its accompanying activation of motor, vestibular, and proprioceptive systems. Researchers should therefore consider the impact on the absence of these motion-based systems when interpreting virtual navigation/functional imaging experiments to achieve a more accurate understanding of the mechanisms underlying navigation.

  5. KSTAR RF heating system development

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, J. G.; Kim, S. K.; Hwang, C. K. (and others)

    2007-10-15

    Design, high-voltage test, and installation of 6 MW ICRF heating system for KSTAR is completed. The antenna demonstrated satisfactory standoff at high voltages up to 41 kV for 300 sec. The result indicates good power handling capabilities of the antenna as high as 10 MW/m2. This power density is equivalent to RF power coupling of 6 MW into a 4 {omega}/m target plasma, and is typical of advanced tokamak heating scenarios. In addition, vacuum feed through, DC break, and liquid stub developed for 300 sec operation are installed, as well as a 2 MW, 30-60MHz transmitter. The transmitter successfully produced output powers of 600 kW continuously, 1.5{approx}1.8 MW for 300 sec, and 2 MW for 100 msec or shorter pulses. A realtime control system based on DSP and EPICS is developed, installed, and tested on the ICRF system. Initial results from feasibility study indicate that the present antenna and the transmission lines could allow load-resilient operation on KSTAR. Until the KSTAR tokamak start to produce plasmas in 2008, however, hands-on operational experiences are obtained from participating in ICRF heating experiments at ASDEX and DIII-D tokamaks arranged through international cooperation.

  6. Modular open RF architecture: extending VICTORY to RF systems

    Science.gov (United States)

    Melber, Adam; Dirner, Jason; Johnson, Michael

    2015-05-01

    Radio frequency products spanning multiple functions have become increasingly critical to the warfighter. Military use of the electromagnetic spectrum now includes communications, electronic warfare (EW), intelligence, and mission command systems. Due to the urgent needs of counterinsurgency operations, various quick reaction capabilities (QRCs) have been fielded to enhance warfighter capability. Although these QRCs were highly successfully in their respective missions, they were designed independently resulting in significant challenges when integrated on a common platform. This paper discusses how the Modular Open RF Architecture (MORA) addresses these challenges by defining an open architecture for multifunction missions that decomposes monolithic radio systems into high-level components with welldefined functions and interfaces. The functional decomposition maximizes hardware sharing while minimizing added complexity and cost due to modularization. MORA achieves significant size, weight and power (SWaP) savings by allowing hardware such as power amplifiers and antennas to be shared across systems. By separating signal conditioning from the processing that implements the actual radio application, MORA exposes previously inaccessible architecture points, providing system integrators with the flexibility to insert third-party capabilities to address technical challenges and emerging requirements. MORA leverages the Vehicular Integration for Command, Control, Communication, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR)/EW Interoperability (VICTORY) framework. This paper concludes by discussing how MORA, VICTORY and other standards such as OpenVPX are being leveraged by the U.S. Army Research, Development, and Engineering Command (RDECOM) Communications Electronics Research, Development, and Engineering Center (CERDEC) to define a converged architecture enabling rapid technology insertion, interoperability and reduced SWaP.

  7. A wideband RF amplifier for satellite tuners

    Science.gov (United States)

    Xueqing, Hu; Zheng, Gong; Yin, Shi; Foster, Dai Fa

    2011-11-01

    This paper presents the design and measured performance of a wideband amplifier for a direct conversion satellite tuner. It is composed of a wideband low noise amplifier (LNA) and a two-stage RF variable gain amplifier (VGA) with linear gain in dB and temperature compensation schemes. To meet the system linearity requirement, an improved distortion compensation technique and a bypass mode are applied on the LNA to deal with the large input signal. Wideband matching is achieved by resistive feedback and an off-chip LC-ladder matching network. A large gain control range (over 80 dB) is achieved by the VGA with process voltage and temperature compensation and dB linearization. In total, the amplifier consumes up to 26 mA current from a 3.3 V power supply. It is fabricated in a 0.35-μm SiGe BiCMOS technology and occupies a silicon area of 0.25 mm2.

  8. Indoor navigation by image recognition

    Science.gov (United States)

    Choi, Io Teng; Leong, Chi Chong; Hong, Ka Wo; Pun, Chi-Man

    2017-07-01

    With the progress of smartphones hardware, it is simple on smartphone using image recognition technique such as face detection. In addition, indoor navigation system development is much slower than outdoor navigation system. Hence, this research proves a usage of image recognition technique for navigation in indoor environment. In this paper, we introduced an indoor navigation application that uses the indoor environment features to locate user's location and a route calculating algorithm to generate an appropriate path for user. The application is implemented on Android smartphone rather than iPhone. Yet, the application design can also be applied on iOS because the design is implemented without using special features only for Android. We found that digital navigation system provides better and clearer location information than paper map. Also, the indoor environment is ideal for Image recognition processing. Hence, the results motivate us to design an indoor navigation system using image recognition.

  9. Rapidly Tunable Dual-Comb RF Photonic Filter for Ultrabroadband RF Spread Spectrum Applications

    OpenAIRE

    Kim, Hyoung-Jun; Leaird, Daniel E.; Weiner, Andrew M.

    2016-01-01

    IEEE Transactions on Microwave Theory and Techniques The article of record as published may be found at http://dx.doi.org/10.1109/tmtt.2016.2599162 We demonstrate a rapidly frequency-tunable radio frequency (RF) filter using microwave photonics technology for ultrawideband RF spread spectrum applications. A pair of electro-optic frequency combs is arranged as a dispersive tapped delay line in a differential detection configuration to implement a programmable finite impulse response RF f...

  10. RF accelerating unit installed in the PSB

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    RF accelerating unit installed in the PSB ring between two bending magnets. Cool air from a heat exchanger is injected into the four cavities from the central feeder and the hot air recirculated via the lateral ducts.

  11. Degreasing and cleaning superconducting RF Niobium cavities

    Energy Technology Data Exchange (ETDEWEB)

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01

    The purpose and scope of this report is to detail the steps necessary for degreasing and cleaning of superconducting RF Niobium cavities in the A0 clean room. It lists the required equipment and the cleaning procedure.

  12. FERMILAB CRYOMODULE TEST STAND RF INTERLOCK SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Troy [Fermilab; Diamond, J. S. [Fermilab; McDowell, D. [Fermilab; Nicklaus, D. [Fermilab; Prieto, P. S. [Fermilab; Semenov, A. [Fermilab

    2016-10-12

    An interlock system has been designed for the Fermilab Cryo-module Test Stand (CMTS), a test bed for the cryo- modules to be used in the upcoming Linac Coherent Light Source 2 (LCLS-II) project at SLAC. The interlock system features 8 independent subsystems, one per superconducting RF cavity and solid state amplifier (SSA) pair. Each system monitors several devices to detect fault conditions such as arcing in the waveguides or quenching of the SRF system. Additionally each system can detect fault conditions by monitoring the RF power seen at the cavity coupler through a directional coupler. In the event of a fault condition, each system is capable of removing RF signal to the amplifier (via a fast RF switch) as well as turning off the SSA. Additionally, each input signal is available for re- mote viewing and recording via a Fermilab designed digitizer board and MVME 5500 processor.

  13. RF synchronized short pulse laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Fuwa, Yasuhiro, E-mail: fuwa@kyticr.kuicr.kyoto-u.ac.jp; Iwashita, Yoshihisa; Tongu, Hiromu; Inoue, Shunsuke; Hashida, Masaki; Sakabe, Shuji [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Okamura, Masahiro [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Yamazaki, Atsushi [Graduate School of Engineering, Nagoya University, Nagoya, Aichi 464-8603 (Japan)

    2016-02-15

    A laser ion source that produces shortly bunched ion beam is proposed. In this ion source, ions are extracted immediately after the generation of laser plasma by an ultra-short pulse laser before its diffusion. The ions can be injected into radio frequency (RF) accelerating bucket of a subsequent accelerator. As a proof-of-principle experiment of the ion source, a RF resonator is prepared and H{sub 2} gas was ionized by a short pulse laser in the RF electric field in the resonator. As a result, bunched ions with 1.2 mA peak current and 5 ns pulse length were observed at the exit of RF resonator by a probe.

  14. Prototype storage cavity for LEP accelerating RF

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The principle of an RF storage cavity was demonstrated with this prototype, working at 500 MHz. Ian Wilso seems to hold it in his hands. The storage cavities had 4 portholes, 1 each for: RF feed; tuning; connection to the accelerating cavity; vacuum pump. The final storage cavities were larger, to suit the lower LEP accelerating frequency of 352.2 MHz. See also 8002294, 8006510X, 8109346, 8407619X, and Annual Report 1980, p.115.

  15. Integrated Photonics Technology and RF over Fiber

    Science.gov (United States)

    2017-03-01

    lmco.com Abstract: Integrated photonics technology has the capability to enable the insertion of RF over Fiber into military platforms. This paper...significantly lower CSWaP [1]. A PIC based RF over Fiber solution could enable this technology to be inserted into many systems as an alternative to...This protection is usually provided via metallic shielding of the conductor. Unfortunately, this translates into cables that are larger and have a

  16. RF/Optical Demonstration: Focal Plane Assembly

    Science.gov (United States)

    Hoppe, D. J.; Chung, S.; Kovalik, J.; Gama, E.; Fernandez, M. M.

    2016-11-01

    In this article, we describe the second-generation focal plane optical assembly employed in the RF/optical demonstration at DSS-13. This assembly receives reflected light from the two mirror segments mounted on the RF primary. The focal plane assembly contains a fast steering mirror (FSM) to stabilize the focal plane spot, a pupil camera to aid in aligning the two segments, and several additional cameras for receiving the optical signal prior to as well as after the FSM loop.

  17. Vortex formation during rf heating of plasma

    Energy Technology Data Exchange (ETDEWEB)

    Motley, R.W.

    1980-05-01

    Experiments on a test plasma show that the linear theory of waveguide coupling to slow plasma waves begins to break down if the rf power flux exceeds approx. 30 W/cm/sup 2/. Probe measurements reveal that within 30 ..mu..s an undulation appears in the surface plasma near the mouth of the twin waveguide. This surface readjustment is part of a vortex, or off-center convective cell, driven by asymmetric rf heating of the plasma column.

  18. RF waveguide phase-directed power combiners

    Science.gov (United States)

    Nantista, Christopher D.; Dolgashev, Valery A.; Tantawi, Sami G.

    2017-05-02

    High power RF phase-directed power combiners include magic H hybrid and/or superhybrid circuits oriented in orthogonal H-planes and connected using E-plane bends and/or twists to produce compact 3D waveguide circuits, including 8.times.8 and 16.times.16 combiners. Using phase control at the input ports, RF power can be directed to a single output port, enabling fast switching between output ports for applications such as multi-angle radiation therapy.

  19. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian

    2017-01-01

    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  20. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  1. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  2. Low reflectance high power RF load

    Energy Technology Data Exchange (ETDEWEB)

    Ives, R. Lawrence; Mizuhara, Yosuke M.

    2016-02-02

    A load for traveling microwave energy has an absorptive volume defined by cylindrical body enclosed by a first end cap and a second end cap. The first end cap has an aperture for the passage of an input waveguide with a rotating part that is coupled to a reflective mirror. The inner surfaces of the absorptive volume consist of a resistive material or are coated with a coating which absorbs a fraction of incident RF energy, and the remainder of the RF energy reflects. The angle of the reflector and end caps is selected such that reflected RF energy dissipates an increasing percentage of the remaining RF energy at each reflection, and the reflected RF energy which returns to the rotating mirror is directed to the back surface of the rotating reflector, and is not coupled to the input waveguide. Additionally, the reflector may have a surface which generates a more uniform power distribution function axially and laterally, to increase the power handling capability of the RF load. The input waveguide may be corrugated for HE11 mode input energy.

  3. Research on the error model of airborne celestial/inertial integrated navigation system

    Science.gov (United States)

    Zheng, Xiaoqiang; Deng, Xiaoguo; Yang, Xiaoxu; Dong, Qiang

    2015-02-01

    Celestial navigation subsystem of airborne celestial/inertial integrated navigation system periodically correct the positioning error and heading drift of the inertial navigation system, by which the inertial navigation system can greatly improve the accuracy of long-endurance navigation. Thus the navigation accuracy of airborne celestial navigation subsystem directly decides the accuracy of the integrated navigation system if it works for long time. By building the mathematical model of the airborne celestial navigation system based on the inertial navigation system, using the method of linear coordinate transformation, we establish the error transfer equation for the positioning algorithm of airborne celestial system. Based on these we built the positioning error model of the celestial navigation. And then, based on the positioning error model we analyze and simulate the positioning error which are caused by the error of the star tracking platform with the MATLAB software. Finally, the positioning error model is verified by the information of the star obtained from the optical measurement device in range and the device whose location are known. The analysis and simulation results show that the level accuracy and north accuracy of tracking platform are important factors that limit airborne celestial navigation systems to improve the positioning accuracy, and the positioning error have an approximate linear relationship with the level error and north error of tracking platform. The error of the verification results are in 1000m, which shows that the model is correct.

  4. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao

    2009-05-01

    Full Text Available The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena.

    Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB L-band scintillation events, adversely affecting the GPS based navigation.

  5. Comparison of RF spectrum prediction methods for dynamic spectrum access

    Science.gov (United States)

    Kovarskiy, Jacob A.; Martone, Anthony F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Narayanan, Ram M.

    2017-05-01

    Dynamic spectrum access (DSA) refers to the adaptive utilization of today's busy electromagnetic spectrum. Cognitive radio/radar technologies require DSA to intelligently transmit and receive information in changing environments. Predicting radio frequency (RF) activity reduces sensing time and energy consumption for identifying usable spectrum. Typical spectrum prediction methods involve modeling spectral statistics with Hidden Markov Models (HMM) or various neural network structures. HMMs describe the time-varying state probabilities of Markov processes as a dynamic Bayesian network. Neural Networks model biological brain neuron connections to perform a wide range of complex and often non-linear computations. This work compares HMM, Multilayer Perceptron (MLP), and Recurrent Neural Network (RNN) algorithms and their ability to perform RF channel state prediction. Monte Carlo simulations on both measured and simulated spectrum data evaluate the performance of these algorithms. Generalizing spectrum occupancy as an alternating renewal process allows Poisson random variables to generate simulated data while energy detection determines the occupancy state of measured RF spectrum data for testing. The results suggest that neural networks achieve better prediction accuracy and prove more adaptable to changing spectral statistics than HMMs given sufficient training data.

  6. Aerial robot navigation in cluttered urban environments

    Science.gov (United States)

    Shi, Dongqing

    Autonomous navigation systems for mobile robots have been successfully deployed for a wide range of planar ground-based tasks. However, very few counterparts of the previous planar navigation systems were developed for three-dimensional (3-D) motion, which is needed for unmanned aerial vehicles (UAVs). Safe maneuvering in complex environments is a major challenge for UAVs. Future urban reconnaissance and search missions will require UAVs to autonomously navigate through cluttered urban spaces. This research proposes two approaches for unmanned helicopter navigation in cluttered urban environments: a 3-D fuzzy behavioral approach and a 3-D vector field histogram (VFH) approach. Behavior-based control has been very successful for planar mobile robots navigation in unknown environments. A novel fuzzy behavioral scheme for navigating an unmanned helicopter in cluttered 3-D spaces is developed. The 3-D navigation problem is decomposed into several identical two-dimensional (2-D) navigation sub-problems, each of which is solved by using preference-based fuzzy behaviors. Due to the shortcomings of vector summation during the fusion of the 2-D sub-problems, instead of directly outputting steering subdirections by their own defuzzification processes, the undefuzzified intermediate results of the sub-problems are fused to a 3-D solution region, representing degrees of preference for the robot movement. A new defuzzification algorithm that steers the robot by finding the centroid of a 3-D convex region of maximum volume in the 3-D solution region is developed. A fuzzy speed control system is also developed to ensure the efficiency and safety of the navigation. The VFH approach is very popular for planar mobile robots. A 3-D VFH approach to UAV navigation in cluttered urban environments is developed. A 3-D laser measurement system is used to obtain the obstacle distribution in this method. Instead of a 2-D Cartesian histogram grid as a world model, a 3-D spherical histogram

  7. Nano-electromechanical oscillators (NEMOs) for RF technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Joel Robert; Czaplewski, David A.; Gibson, John Murray (Argonne National Laboratory, Argonne, IL); Webster, James R.; Carton, Andrew James; Keeler, Bianca Elizabeth Nelson; Carr, Dustin Wade; Friedmann, Thomas Aquinas; Tallant, David Robert; Boyce, Brad Lee; Sullivan, John Patrick; Dyck, Christopher William; Chen, Xidong (Cedarville University, Cedarville, OH)

    2004-12-01

    Nano-electromechanical oscillators (NEMOs), capacitively-coupled radio frequency (RF) MEMS switches incorporating dissipative dielectrics, new processing technologies for tetrahedral amorphous carbon (ta-C) films, and scientific understanding of dissipation mechanisms in small mechanical structures were developed in this project. NEMOs are defined as mechanical oscillators with critical dimensions of 50 nm or less and resonance frequencies approaching 1 GHz. Target applications for these devices include simple, inexpensive clocks in electrical circuits, passive RF electrical filters, or platforms for sensor arrays. Ta-C NEMO arrays were used to demonstrate a novel optomechanical structure that shows remarkable sensitivity to small displacements (better than 160 fm/Hz {sup 1/2}) and suitability as an extremely sensitive accelerometer. The RF MEMS capacitively-coupled switches used ta-C as a dissipative dielectric. The devices showed a unipolar switching response to a unipolar stimulus, indicating the absence of significant dielectric charging, which has historically been the major reliability issue with these switches. This technology is promising for the development of reliable, low-power RF switches. An excimer laser annealing process was developed that permits full in-plane stress relaxation in ta-C films in air under ambient conditions, permitting the application of stress-reduced ta-C films in areas where low thermal budget is required, e.g. MEMS integration with pre-existing CMOS electronics. Studies of mechanical dissipation in micro- and nano-scale ta-C mechanical oscillators at room temperature revealed that mechanical losses are limited by dissipation associated with mechanical relaxation in a broad spectrum of defects with activation energies for mechanical relaxation ranging from 0.35 eV to over 0.55 eV. This work has established a foundation for the creation of devices based on nanomechanical structures, and outstanding critical research areas that need

  8. Ionospheric modelling for navigation

    Science.gov (United States)

    Aragon Angel, M. A.

    Signals transmitted to and from satellites for communication and navigation purposes must pass through the ionosphere Ionospheric irregularities most common at equatorial latitudes although they could occur anywhere can have a major impact on system performance and reliability and commercial navigation service satellite-based providers need to account for their effects For a GNSS single-frequency receiver the Slant Total Electron Content STEC must be known by the user through broadcast corrections In this context there are several sets of broadcast parameters that can be defined to take into account this ionospheric term The chosen model to generate the ionospheric correction coefficients for the present study is the NeQuick model although with a number of adaptations intended to improve effective ionospheric effect modelling performances The aim of this study is to describe a possible adaptation to the NeQuick model for real time purposes and suitable for single frequency users Therefore it will be necessary to determine the performance of this modified NeQuick model in correcting the ionospheric delay In order to generate the ionospheric corrections for single frequency receivers using the NeQuick model a certain approach should be followed to adapt the performance of NeQuick since this model was originally developed to provide TEC using averaged monthly information of the solar activity and not daily one Thus to use NeQuick for real time applications as an ionospheric broadcasted model such as Klobuchar solar daily information at the user point

  9. BRS 369RF and BRS 370RF: Glyphosate tolerant, high-yielding upland cotton cultivars for central Brazilian savanna

    Directory of Open Access Journals (Sweden)

    Camilo de Lelis Morello

    2015-12-01

    Full Text Available BRS 369RF and BRS 370RF were developed by the EMBRAPA as a part of efforts to create high-yielding germplasm with combinations of transgenic traits. BRS 369RF and BRS 370RF are midseason cultivars and have yield stability, adaptation to the central Brazilian savanna, good fiber quality and tolerance to glyphosate herbicide.

  10. Learning navigation – Learning with navigation. A review

    Directory of Open Access Journals (Sweden)

    Jenny Jean-Yves

    2017-01-01

    Full Text Available The goal of this review paper is to retrieve from the existing literature relevant information (1 about the learning curve of the currently existing navigation systems and (2 about the use of navigation system for teaching orthopaedic procedures. All studies reporting on the learning curve of navigation systems support the hypothesis that computer-navigated total knee arthroplasty (TKA involves only a short learning curve and that beginners can obtain good results from the beginning of their experience, as navigation provides continuous feedback during all phases of the knee replacement surgery and allows for correcting any bone cut errors. Interestingly, there is no comparable research on the learning curve of TKA with standard, manual instrumentation. One might postulate that this learning curve might be longer than with navigation, with potentially a higher rate of outliers. The current literature does support that navigation may be an efficient teaching tool for both experienced orthopaedic surgeons and trainees. Experienced surgeons may improve their skills with conventional techniques and learn new techniques more efficiently and more quickly. Trainees may have a better understanding of the procedure and learn standard techniques with a shorter learning curve. This is probably due to the immediate feedback of navigation systems. A shorter learning curve may be associated with improved clinical and functional results for the patient during this critical period. However, there is no evidence that training with navigation excludes trainees from the need to work in academic environments with experienced teachers. Future techniques in training may include the development of laboratory simulation procedures using navigated feedback.

  11. Learning navigation – Learning with navigation. A review

    Science.gov (United States)

    Jenny, Jean-Yves; Picard, Frederic

    2017-01-01

    The goal of this review paper is to retrieve from the existing literature relevant information (1) about the learning curve of the currently existing navigation systems and (2) about the use of navigation system for teaching orthopaedic procedures. All studies reporting on the learning curve of navigation systems support the hypothesis that computer-navigated total knee arthroplasty (TKA) involves only a short learning curve and that beginners can obtain good results from the beginning of their experience, as navigation provides continuous feedback during all phases of the knee replacement surgery and allows for correcting any bone cut errors. Interestingly, there is no comparable research on the learning curve of TKA with standard, manual instrumentation. One might postulate that this learning curve might be longer than with navigation, with potentially a higher rate of outliers. The current literature does support that navigation may be an efficient teaching tool for both experienced orthopaedic surgeons and trainees. Experienced surgeons may improve their skills with conventional techniques and learn new techniques more efficiently and more quickly. Trainees may have a better understanding of the procedure and learn standard techniques with a shorter learning curve. This is probably due to the immediate feedback of navigation systems. A shorter learning curve may be associated with improved clinical and functional results for the patient during this critical period. However, there is no evidence that training with navigation excludes trainees from the need to work in academic environments with experienced teachers. Future techniques in training may include the development of laboratory simulation procedures using navigated feedback. PMID:28573966

  12. Acoustic Sensors for Air and Surface Navigation Applications.

    Science.gov (United States)

    Kapoor, Rohan; Ramasamy, Subramanian; Gardi, Alessandro; Schyndel, Ron Van; Sabatini, Roberto

    2018-02-07

    This paper presents the state-of-the-art and reviews the state-of-research of acoustic sensors used for a variety of navigation and guidance applications on air and surface vehicles. In particular, this paper focuses on echolocation, which is widely utilized in nature by certain mammals (e.g., cetaceans and bats). Although acoustic sensors have been extensively adopted in various engineering applications, their use in navigation and guidance systems is yet to be fully exploited. This technology has clear potential for applications in air and surface navigation/guidance for Intelligent Transport Systems (ITS), especially considering air and surface operations indoors and in other environments where satellite positioning is not available. Propagation of sound in the atmosphere is discussed in detail, with all potential attenuation sources taken into account. The errors introduced in echolocation measurements due to Doppler, multipath and atmospheric effects are discussed, and an uncertainty analysis method is presented for ranging error budget prediction in acoustic navigation applications. Considering the design challenges associated with monostatic and multi-static sensor implementations and looking at the performance predictions for different possible configurations, acoustic sensors show clear promises in navigation, proximity sensing, as well as obstacle detection and tracking. The integration of acoustic sensors in multi-sensor navigation systems is also considered towards the end of the paper and a low Size, Weight and Power, and Cost (SWaP-C) sensor integration architecture is presented for possible introduction in air and surface navigation systems.

  13. Autonomous Real-time Relative Navigation for Formation Flying Satellites

    Directory of Open Access Journals (Sweden)

    Sunhwa Shim

    2009-03-01

    Full Text Available Relative navigation system is presented using GPS measurements from a single-channel global positioning system (GPS simulator. The objective of this study is to provide the real-time inter-satellite relative positions as well as absolute positions for two formation flying satellites in low earth orbit. To improve the navigation performance, the absolute states are estimated using ion-free GRAPHIC (group and phase ionospheric correction pseudo-ranges and the relative states are determined using double differential carrier-phase data and singled-differential C/A code data based on the extended Kalman filter and the unscented Kalman filter. Furthermore, pseudo-relative dynamic model and modified relative measurement model are developed. This modified EKF method prevents non-linearity of the measurement model from degrading precision by applying linearization about absolute navigation solutions not about the priori estimates. The LAMBDA method also has been used to improve the relative navigation performance by fixing ambiguities to integers for precise relative navigation. The software-based simulation has been performed and the steady state accuracies of 1 m and 6 mm ( of 3-dimensional difference errors are achieved for the absolute and relative navigation using EKF for a short baseline leader/follower formation. In addition, the navigation performances are compared for the EKF and the UKF for 10 hours simulation, and relative position errors are mm-level for the two filters showing the similar trends.

  14. Correlation of Virtual Aids to Navigation to the Physical Environment

    Directory of Open Access Journals (Sweden)

    R. Glenn Wright

    2016-07-01

    Full Text Available Virtual electronic aids to navigation are being introduced into the present short range aids to navigation system in the form of Automated Information System radio-based aids. Research is also underway into the development of their equivalents for use in regions that feature hostile environments, are poorly charted and lack any infrastructure whatsoever to support traditional or radio navigation aids. Such aids are entirely virtual in nature and exist only as a digital data object that resides within an electronic navigation chart for display to mariners through an Electronic Chart Display and Information System. They are at present experimental in nature, and are not intended to replace existing physical or radio-based aids to navigation. Results of research are described in terms of fulfilling traditional navigation aid functions and the development of new functions that are only possible using virtual aids. Their advantages in design and implementation are highlighted, as are their limitations and shortcomings as compared to present methodologies. Notable, however, is the approach used to overcome limitations and shortcomings by considering attributes of the physical environment to ensure their proper location and display of correct characteristics. Such an approach is unique in the modern world, yet it emulates ancient methods of navigation using known landmarks and terrain features.

  15. Improved Range Searching Lower Bounds

    DEFF Research Database (Denmark)

    Larsen, Kasper Green; Nguyen, Huy L.

    2012-01-01

    by constructing a hard input set and query set, and then invoking Chazelle and Rosenberg's [CGTA'96] general theorem on the complexity of navigation in the pointer machine. For the group model, we show that input sets and query sets that are hard for range reporting in the pointer machine (i.e. by Chazelle...

  16. Lunar optical wireless communication and navigation network for robotic and human exploration

    Science.gov (United States)

    Arnon, Shlomi

    2011-09-01

    Exploration of the moon is a stepping stone for further research of our solar system, the galaxy and, ultimately, the universe. Many intriguing questions arise regarding the moon; what is the moon's composition and structure, what is the potential for settlement or colonization and how did our solar system evolve to name a few. New technologies are required in order to answer these questions. The main goal in our project is to develop technologies for optical wireless communication and navigation systems for use in robotic and in human exploration on the moon. These technologies facilitate the exploration of the moon surface by enabling placing scientific equipment at precise locations and subsequently transferring the acquired information at high data rates. The main advantages of optical technology in comparison with RF technology are: a) high data rate transmission, b) small size and weight of equipment, c) low power consumption, d) very high accuracy in measuring range and orientation and e) no contamination of the quiet electromagnetic (EM) environment on the dark side of the moon In this paper we present a mathematical model and an engineering implementation of a system that simultaneously communicates, and measures the location and orientation of a remote robot on the moon.

  17. Computer Navigation-aided Resection of Sacral Chordomas

    Directory of Open Access Journals (Sweden)

    Yong-Kun Yang

    2016-01-01

    Full Text Available Background: Resection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas. Methods: Between 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old (range: 35-84 years old. Tumors were located above the level of the S3 neural foramen in 23 patients and below the level of the S3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months (range: 18-84 months. Results: Mean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 mm. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 (7.7% exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 (range: 19-30. Conclusions: Computer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.

  18. INFORMATION SPACE RESEARCH IN NAVIGATION

    Directory of Open Access Journals (Sweden)

    Gennadiy Vilsky

    2011-03-01

    Full Text Available Abctract. Considered the problems information space navigation and the ship, as the object of informationsecurity waterways. Formed the category of information flows for modeling their interactions in order to prioritizethe information space navigation. Investigated priority flows ship information in a continuous exchange ofinformation, allowing to increase the safety of navigation. Shows an embodiment of methods of surgical analysis ofthe information space and its application in the formation of information impacts on the management of the vessel.Using matrix and Graphology analysis carried out studies of information flow in the navigation. Justified the priorityobjective and focus of the proposed method. Shows a computer visualization prioritization of information flows.Results of the study the information space will create the information - analytical system for the provision of servicesto ships under continuous threats and risks.Keywords: waterway, navigation, information flows, information security, information space model,graph, matrix state priority.

  19. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland

    2014-09-21

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A

  20. Dynamic Transportation Navigation

    Science.gov (United States)

    Meng, Xiaofeng; Chen, Jidong

    Miniaturization of computing devices, and advances in wireless communication and sensor technology are some of the forces that are propagating computing from the stationary desktop to the mobile outdoors. Some important classes of new applications that will be enabled by this revolutionary development include intelligent traffic management, location-based services, tourist services, mobile electronic commerce, and digital battlefield. Some existing application classes that will benefit from the development include transportation and air traffic control, weather forecasting, emergency response, mobile resource management, and mobile workforce. Location management, i.e., the management of transient location information, is an enabling technology for all these applications. In this chapter, we present the applications of moving objects management and their functionalities, in particular, the application of dynamic traffic navigation, which is a challenge due to the highly variable traffic state and the requirement of fast, on-line computations.

  1. Focusing properties of discrete RF quadrupoles

    Science.gov (United States)

    Li, Zhi-Hui; Wang, Zhi-Jun

    2017-08-01

    The particle motion equation for a Radio Frequency (RF) quadrupole is derived. The motion equation shows that the general transform matrix of a RF quadrupole with length less than or equal to 0.5βλ (β is the relativistic velocity of particles and λ is wavelength of radio frequency electromagnetic field) can describe the particle motion in an arbitrarily long RF quadrupole. By iterative integration, the general transform matrix of a discrete RF quadrupole is derived from the motion equation. The transform matrix is in form of a power series of focusing parameter B. It shows that for length less than βλ, the series up to the 2nd order of B agrees well with the direct integration results for B up to 30, while for length less than 0.5βλ, the series up to 1st order is already a good approximation of the real solution for B less than 30. The formula of the transform matrix can be integrated into linac or beam line design code to deal with the focusing of discrete RF quadrupoles. Supported by National Natural Science Foundation of China (11375122, 11511140277) and Strategic Priority Research Program of the Chinese Academy of Sciences (XDA03020705)

  2. RF Electromagnetic Field Treatment of Tetragonal Kesterite CZTSSe Light Absorbers

    Science.gov (United States)

    Semenenko, Mykola O.; Babichuk, Ivan S.; Kyriienko, Oleksandr; Bodnar, Ivan V.; Caballero, Raquel; Leon, Maximo

    2017-06-01

    In this work, we propose a method to improve electro-optical and structural parameters of light-absorbing kesterite materials. It relies on the application of weak power hydrogen plasma discharges using electromagnetic field of radio frequency range, which improves homogeneity of the samples. The method allows to reduce strain of light absorbers and is suitable for designing solar cells based on multilayered thin film structures. Structural characteristics of tetragonal kesterite Cu2ZnSn(S, Se)4 structures and their optical properties were studied by Raman, infrared, and reflectance spectroscopies. They revealed a reduction of the sample reflectivity after RF treatment and a modification of the energy band structure.

  3. Handbook of RF, microwave, and millimeter-wave components

    CERN Document Server

    Smolskiy, Sergey M; Kochemasov, Victor N

    2012-01-01

    This unique and comprehensive resource offers you a detailed treatment of the operations principles, key parameters, and specific characteristics of active and passive RF, microwave, and millimeter-wave components. The book covers both linear and nonlinear components that are used in a wide range of application areas, from communications and information sciences, to avionics, space, and military engineering. This practical book presents descriptions and clear examples and of the best materials and products used in the field, including laminates, prepregs, substrates; microstrip, coaxial and wa

  4. Modelling and Simulation of RF Multilayer Inductors in LTCC Technology

    Directory of Open Access Journals (Sweden)

    A. Čelić

    2009-11-01

    Full Text Available This paper is aimed at presenting the models and characteristics of two types of inductors designed in LTCC (Low Temperature Cofired Ceramic technology. We present the physical model of a 3D planar solenoid-type inductor and of a serial planar solenoid-type inductor for the RF (radio frequency range. To verify the results obtained by using these models, we have compared them with the results obtained by employing the Ansoft HFSS electromagnetic simulator. Very good agreement has been recorded for the effective inductance value, whereas the effective Q factor value has shown a somewhat larger deviation than the inductance.

  5. Synchronization of multiple coupled rf-SQUID flux qubits

    Science.gov (United States)

    Harris, R.; Brito, F.; Berkley, A. J.; Johansson, J.; Johnson, M. W.; Lanting, T.; Bunyk, P.; Ladizinsky, E.; Bumble, B.; Fung, A.; Kaul, A.; Kleinsasser, A.; Han, S.

    2009-12-01

    A practical strategy for synchronizing the properties of compound Josephson junction (CJJ) radio frequency monitored superconducting quantum interference device (rf-SQUID) qubits on a multi-qubit chip has been demonstrated. The impact of small (~1%) fabrication variations in qubit inductance and critical current can be minimized by the application of a custom-tuned flux offset to the CJJ structure of each qubit. This strategy allows for a simultaneous synchronization of the qubit persistent current and tunnel splitting over a range of external bias parameters that is relevant for the implementation of an adiabatic quantum processor.

  6. Experimental Study of RF Energy Transfer System in Indoor Environment

    Science.gov (United States)

    Adami, S.-E.; Proynov, P. P.; Stark, B. H.; Hilton, G. S.; Craddock, I. J.

    2014-11-01

    This paper presents a multi-transmitter, 2.43 GHz Radio-Frequency (RF) wireless power transfer (WPT) system for powering on-body devices. It is shown that under typical indoor conditions, the received power range spans several orders of magnitude from microwatts to milliwatts. A body-worn dual-polarised rectenna (rectifying antenna) is presented, designed for situations where the dominant polarization is unpredictable, as is the case for the on-body sensors. Power management circuitry is demonstrated that optimally loads the rectenna even under highly intermittent conditions, and boosts the voltage to charge an on-board storage capacitor.

  7. Differential RF MEMS interwoven capacitor immune to residual stress warping

    KAUST Repository

    Elshurafa, Amro M.

    2012-07-27

    A RF MEMS capacitor with an interwoven structure is designed, fabricated in the PolyMUMPS process and tested in an effort to address fabrication challenges usually faced in MEMS processes. The interwoven structure was found to offer several advantages over the typical MEMS parallel-plate design including eliminating the warping caused by residual stress, eliminating the need for etching holes, suppressing stiction, reducing parasitics and providing differential capability. The quality factor of the proposed capacitor was higher than five throughout a 2–10 GHz range and the resonant frequency was in excess of 20 GHz.

  8. Reactive navigation in dynamic environment using a multisensor predictor.

    Science.gov (United States)

    Song, K T; Chang, C C

    1999-01-01

    A reactive navigation system for an autonomous mobile robot in unstructured dynamic environments is presented. The motion of moving obstacles is estimated for robot motion planning and obstacle avoidance. A multisensor-based obstacle predictor is utilized to obtain obstacle-motion information. Sensory data from a CCD camera and multiple ultrasonic range finders are combined to predict obstacle positions at the next sampling instant. A neural network, which is trained off-line, provides the desired prediction on-line in real time. The predicted obstacle configuration is employed by the proposed virtual force based navigation method to prevent collision with moving obstacles. Simulation results are presented to verify the effectiveness of the proposed navigation system in an environment with multiple mobile robots or moving objects. This system was implemented and tested on an experimental mobile robot at our laboratory. Navigation results in real environment are presented and analyzed.

  9. Mars Atmospheric Entry Integrated Navigation with Partial Intermittent Measurements

    Directory of Open Access Journals (Sweden)

    Tai-shan Lou

    2017-01-01

    Full Text Available Signal degradation suffered by the vehicle is a combination brownout and blackout during Mars atmospheric entry. The communications brownout means that signal fades and blackout means that the signal is lost completely. The communications brownout and blackout periods are analyzed and predicted with an altitude and velocity profiles. In the brownout period, the range measurements between the vehicle and the orbiters are modeled as intermittent measurements with the radio signal arrival probabilities, which are distributed as a Rayleigh distribution of the electron number density around the entry vehicle. A new integrated navigation strategy during the Mars atmospheric entry phase is proposed to consider the probabilities of the radio measurements in the communications brownout and blackout periods under the IMU/beacon scenario based on the information filter with intermittent measurements. Numerical navigation simulations are designed to show the performance of the proposed navigation strategy under the integrated navigation scenario.

  10. High RF Power Production for CLIC

    CERN Document Server

    Syratchev, I; Adli, E; Taborelli, M

    2007-01-01

    The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and excite preferentially the synchronous mode. The RF power produced (several hundred MW) is collected at the downstream end of the structure by means of the Power Extractor and delivered to the main linac structure. The PETS geometry is a result of multiple compromises between beam stability and main linac RF power needs. Another requirement is to provide local RF power termination in case of accelerating structure failure (ON/OFF capability). Surface electric and magnetic fields, power extraction method, HOM damping, ON/OFF capability and fabrication technology were all evaluated to provide a reliable design

  11. Investigation of RF Signal Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Soudeh Heydari Nasab

    2010-01-01

    Full Text Available The potential utilization of RF signals for DC power is experimentally investigated. The aim of the work is to investigate the levels of power that can be harvested from the air and processed to achieve levels of energy that are sufficient to charge up low-power electronic circuits. The work presented shows field measurements from two selected regions: an urbanized hence signal congested area and a less populated one. An RF harvesting system has been specifically designed, built, and shown to successfully pick up enough energy to power up circuits. The work concludes that while RF harvesting was successful under certain conditions, however, it required the support of other energy harvesting techniques to replace a battery. Efficiency considerations have, hence, placed emphasis on comparing the developed harvester to other systems.

  12. Linear bearing device as a solution for optical navigation of fine needle procedures.

    Science.gov (United States)

    Stüber, Volker; Suero, Eduardo M; H U Fner, Tobias; Wiewiorski, Martin; Krettek, Christian; Citak, Musa

    2010-01-01

    Optical navigation of needles trajectory. Accuracy of this device was analyzed with two setups (A = ballistic gelatin; B = used pork meat). For both setups, a Plexiglas cube with integrated Plexiglas reference arrays was used. Metal targets of 1 mm diameter were placed in the center. Images were acquired using a 3D fluoroscope connected to a conventional optical navigation system. After trajectory planning, ten navigated injections were performed freehand and with the linear bearing device for each setup. A 3D scan was performed to measure the distance between contrast medium and metal target after each injection. Freehand navigation with a needle of 0.9 mm in diameter was not accurate with either setup (Setup A: mean 33.4 mm; range, 3-63 mm; Setup B: mean 40.1 mm; range, 12-75 mm). Linear bearing navigation was significant more precisely (Setup A: mean 0.7 mm; range, 0-0.75 mm; Setup B: mean 0.29 mm, range 0-1.3 mm) than freehand navigation. The linear bearing device reduced all bending. Optical fine needle navigation was accomplished with precision comparable to electromagnetic navigation. This device may provide useful for minimally-invasive clinical applications. Follow-up studies should compare electromagnetic and optical navigation systems in the same setup.

  13. 33 CFR 159.115 - Temperature range test.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Temperature range test. 159.115...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.115 Temperature range test. (a) The device must be held at a temperature of 60 °C or higher for a period of 16 hours. (b) The device...

  14. Design of an L-band normally conducting RF gun cavity for high peak and average RF power

    Energy Technology Data Exchange (ETDEWEB)

    Paramonov, V., E-mail: paramono@inr.ru [Institute for Nuclear Research of Russian Academy of Sciences, 60-th October Anniversary prospect 7a, 117312 Moscow (Russian Federation); Philipp, S. [Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Rybakov, I.; Skassyrskaya, A. [Institute for Nuclear Research of Russian Academy of Sciences, 60-th October Anniversary prospect 7a, 117312 Moscow (Russian Federation); Stephan, F. [Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

    2017-05-11

    To provide high quality electron bunches for linear accelerators used in free electron lasers and particle colliders, RF gun cavities operate with extreme electric fields, resulting in a high pulsed RF power. The main L-band superconducting linacs of such facilities also require a long RF pulse length, resulting in a high average dissipated RF power in the gun cavity. The newly developed cavity based on the proven advantages of the existing DESY RF gun cavities, underwent significant changes. The shape of the cells is optimized to reduce the maximal surface electric field and RF loss power. Furthermore, the cavity is equipped with an RF probe to measure the field amplitude and phase. The elaborated cooling circuit design results in a lower temperature rise on the cavity RF surface and permits higher dissipated RF power. The paper presents the main solutions and results of the cavity design.

  15. Design of an L-band normally conducting RF gun cavity for high peak and average RF power

    Science.gov (United States)

    Paramonov, V.; Philipp, S.; Rybakov, I.; Skassyrskaya, A.; Stephan, F.

    2017-05-01

    To provide high quality electron bunches for linear accelerators used in free electron lasers and particle colliders, RF gun cavities operate with extreme electric fields, resulting in a high pulsed RF power. The main L-band superconducting linacs of such facilities also require a long RF pulse length, resulting in a high average dissipated RF power in the gun cavity. The newly developed cavity based on the proven advantages of the existing DESY RF gun cavities, underwent significant changes. The shape of the cells is optimized to reduce the maximal surface electric field and RF loss power. Furthermore, the cavity is equipped with an RF probe to measure the field amplitude and phase. The elaborated cooling circuit design results in a lower temperature rise on the cavity RF surface and permits higher dissipated RF power. The paper presents the main solutions and results of the cavity design.

  16. RF installation for the grain disinfestation

    CERN Document Server

    Zajtzev, B V; Kobetz, A F; Rudiak, B I

    2001-01-01

    The ecologically pure method of grain product disinfestations through the grain treatment with the RF electric field is described. The experimental data obtained showed that with strengths of the electrical RF field of E=5 kV/cm and frequency of 80 MHz the relative death rate is 100%.The time of the grain treatment it this case is 1 sec. The pulses with a duration of 600 mu s and repetition rate of 2 Hz were used, the duration of the front was 10 mu s. The schematic layout of installation with a productivity of 50 tones/h and power of 10 kW is given.

  17. Lumped elements for RF and microwave circuits

    CERN Document Server

    Bahl, Inder

    2003-01-01

    Due to the unprecedented growth in wireless applications over the past decade, development of low-cost solutions for RF and microwave communication systems has become of great importance. This practical new book is the first comprehensive treatment of lumped elements, which are playing a critical role in the development of the circuits that make these cost-effective systems possible. The books offers you an in-depth understanding of the different types of RF and microwave circuit elements, including inductors, capacitors, resistors, transformers, via holes, airbridges, and crossovers. Support

  18. Navigable networks as Nash equilibria of navigation games

    Science.gov (United States)

    Gulyás, András; Bíró, József J.; Kőrösi, Attila; Rétvári, Gábor; Krioukov, Dmitri

    2015-01-01

    Common sense suggests that networks are not random mazes of purposeless connections, but that these connections are organized so that networks can perform their functions well. One function common to many networks is targeted transport or navigation. Here, using game theory, we show that minimalistic networks designed to maximize the navigation efficiency at minimal cost share basic structural properties with real networks. These idealistic networks are Nash equilibria of a network construction game whose purpose is to find an optimal trade-off between the network cost and navigability. We show that these skeletons are present in the Internet, metabolic, English word, US airport, Hungarian road networks, and in a structural network of the human brain. The knowledge of these skeletons allows one to identify the minimal number of edges, by altering which one can efficiently improve or paralyse navigation in the network. PMID:26138277

  19. Navigable networks as Nash equilibria of navigation games

    Science.gov (United States)

    Gulyás, András; Bíró, József J.; Kőrösi, Attila; Rétvári, Gábor; Krioukov, Dmitri

    2015-07-01

    Common sense suggests that networks are not random mazes of purposeless connections, but that these connections are organized so that networks can perform their functions well. One function common to many networks is targeted transport or navigation. Here, using game theory, we show that minimalistic networks designed to maximize the navigation efficiency at minimal cost share basic structural properties with real networks. These idealistic networks are Nash equilibria of a network construction game whose purpose is to find an optimal trade-off between the network cost and navigability. We show that these skeletons are present in the Internet, metabolic, English word, US airport, Hungarian road networks, and in a structural network of the human brain. The knowledge of these skeletons allows one to identify the minimal number of edges, by altering which one can efficiently improve or paralyse navigation in the network.

  20. Integrated PET/MR imaging: automatic attenuation correction of flexible RF coils.

    Science.gov (United States)

    Kartmann, René; Paulus, Daniel H; Braun, Harald; Aklan, Bassim; Ziegler, Susanne; Navalpakkam, Bharath K; Lentschig, Markus; Quick, Harald H

    2013-08-01

    of the phantoms and 15.5% for a lesion near the body surface of the patient was measured close to the high attenuating hardware components of the RF coils. The attenuation maps generated by the registration algorithm reduced the quantification errors due to the RF surface coils to values ranging from -3.9% to 4.3%. Concerning the volunteer examinations, the attenuation templates of the three RF surface coils were registered to their correct positions with an overall accuracy of about 3 mm. The presence of flexible RF surface coils leads to considerable local errors in the simultaneously measured PET activity concentration up to 15.5% especially in regions close to the coils. The presented automatic algorithm accurately and reliably reduces the PET quantification errors caused by multiple partly overlapping flexible RF surface coils to values of 4.3% or better.

  1. Cryoelectron Microscopic Structures of Eukaryotic Translation Termination Complexes Containing eRF1-eRF3 or eRF1-ABCE1

    Directory of Open Access Journals (Sweden)

    Anne Preis

    2014-07-01

    Full Text Available Termination and ribosome recycling are essential processes in translation. In eukaryotes, a stop codon in the ribosomal A site is decoded by a ternary complex consisting of release factors eRF1 and guanosine triphosphate (GTP-bound eRF3. After GTP hydrolysis, eRF3 dissociates, and ABCE1 can bind to eRF1-loaded ribosomes to stimulate peptide release and ribosomal subunit dissociation. Here, we present cryoelectron microscopic (cryo-EM structures of a pretermination complex containing eRF1-eRF3 and a termination/prerecycling complex containing eRF1-ABCE1. eRF1 undergoes drastic conformational changes: its central domain harboring the catalytically important GGQ loop is either packed against eRF3 or swung toward the peptidyl transferase center when bound to ABCE1. Additionally, in complex with eRF3, the N-terminal domain of eRF1 positions the conserved NIKS motif proximal to the stop codon, supporting its suggested role in decoding, yet it appears to be delocalized in the presence of ABCE1. These results suggest that stop codon decoding and peptide release can be uncoupled during termination.

  2. Orthogonal-coil RF probe for implantable passive sensors.

    Science.gov (United States)

    Talman, James R; Fleischman, Aaron J; Roy, Shuvo

    2006-03-01

    A versatile orthogonal-coil radio frequency (RF) probe suitable for detecting the resonant frequency of miniature implantable passive sensors has been designed and tested. The probe sensitivity has been tested using printed-circuit spiral inductors of various sizes (3-15 mm) in series with discrete surface-mount capacitors designed to resonate over a range of frequencies (50-200 MHz). Close agreement between theoretical calculations and experimental results has been obtained. An equation is derived for transmit/receive (T/R) isolation that agrees with experimental measurements over the frequency range 1-500 MHz. The probe includes an additional coil to compensate for the effect of eddy currents in the human body on the probe. T/R isolation of at least 90 dB over the frequency range 1-100 MHz can be achieved when the probe is placed in close proximity to the human body.

  3. Simulations of S-band RF gun with RF beam control

    Science.gov (United States)

    Barnyakov, A. M.; Levichev, A. E.; Maltseva, M. V.; Nikiforov, D. A.

    2017-08-01

    The RF gun with RF control is discussed. It is based on the RF triode and two kinds of the cavities. The first cavity is a coaxial cavity with cathode-grid assembly where beam bunches are formed, the second one is an accelerating cavity. The features of such a gun are the following: bunched and relativistic beams in the output of the injector, absence of the back bombarding electrons, low energy spread and short length of the bunches. The scheme of the injector is shown. The electromagnetic field simulation and longitudinal beam dynamics are presented. The possible using of the injector is discussed.

  4. Magnetic navigation in percutaneous coronary intervention.

    Science.gov (United States)

    Patterson, Mark S; Schotten, Jeroen; van Mieghem, Carlos; Kiemeneij, Ferdinand; Serruys, Patrick W

    2006-12-01

    Magnetic navigation is the use of adjustable magnetic fields to precisely direct wires and equipment for clinical applications. It is a recently developed option that is now available for interventional cardiology. Procedures are based on the production of a three-dimensional reconstruction of the vessel lumen from standard angiographic images. Knowledge of the positions of the table and image intensifier during angiography allows calculation of the vessel coordinates in real space within the patient's chest. The applied magnetic field can be changed at any time to redirect the wire tip in order to improve navigation through complex and tortuous anatomy. The digital information of the coronary reconstruction can be used in further novel ways. Firstly, the integration of multislice computerized tomography images adds information about the path of the previous lumen of chronic total occlusions. Secondly, the computed center-line of the reconstructed vessel can be superimposed onto the live fluoroscopy images as a three-dimensional guide. The combination of improved navigation together with the other available system features may improve time, contrast, and material usage in a range of coronary lesions. Future potential developments include improvements in equipment and software, and potential therapeutic strategies under consideration include the use of equipment to perform remote control procedures, and the integration of the system to improve bone marrow-derived stem cell delivery.

  5. Radio Navigation Waveform Experiment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is installing the Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) onto the truss of the International Space Station to demonstrate...

  6. Potential applications of satellite navigation

    Science.gov (United States)

    Schaenzer, G.

    The applicability of Navstar GPS to civil air navigation is discussed. The accuracy of current air-navigation systems is reviewed; the basic principle and accuracy of GPS navigation are characterized; the relatively low cost of GPS receiving equipment is pointed out; and particular attention is given to hybrid systems combining GPS with inertial navigation. It is predicted that CAT III landings will be possible using such hybrid systems when the GPS satellites are fully deployed, even without access to the military GPS code. Techniques for GPS-based precision landings, reduced-noise landings, landings on parallel runways, control of taxiing maneuvers, and aircraft-based geodetic measurements are briefly described and illustrated with diagrams.

  7. Almanac services for celestial navigation

    Science.gov (United States)

    Nelmes, S.; Whittaker, J.

    2015-08-01

    Celestial navigation remains a vitally important back up to Global Navigation Satellite Systems (GNSS) and relies on the use of almanac services. HM Nautical Almanac Office (HMNAO) provides a number of these services. The printed book, The Nautical Almanac, produced yearly and now available as an electronic publication, is continuously being improved, making use of the latest ideas and ephemerides to provide the user with their required data. HMNAO also produces NavPac, a software package that assists the user in calculating their position as well as providing additional navigational and astronomical tools. A new version of NavPac will be released in 2015 that will improve the user experience. The development of applications for mobile devices is also being considered. HMNAO continues to combine the latest improvements and theories of astrometry with the creation of books and software that best meet the needs of celestial navigation users.

  8. NOAA Electronic Navigational Charts (ENC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Office of Coast Survey (OCS) has been involved in the development of a NOAA Electronic Navigational Chart (NOAA ENC) suite to support the marine transportation...

  9. Navigable Waterway Network Node Locations

    Data.gov (United States)

    Department of Homeland Security — The National Waterway Network is a comprehensive network database of the nation's navigable waterways. The data set covers the 48 contiguous states plus the District...

  10. Slot-finger superconducting structure with rf focusing

    Directory of Open Access Journals (Sweden)

    Yu. Senichev

    2005-07-01

    Full Text Available The linear accelerator based on a superconducting structure with a high accelerating gradient accordingly has a strong rf defocusing factor. Usually, a quadrupole or solenoid focusing system is used in such accelerators. Both of these systems complicate the linear accelerator. The quadrupoles are located outside the cavity and a transition between the cold and the warm systems is required. Therefore an additional drift space between cryostats is needed, which can cause parametric resonance in the longitudinal plane in the energy range of (3–20  MeV. In the system with the solenoid the high magnetic field can affect the superconductivity. We consider the novel superconducting H resonator based on the TE211 mode with a slot and rf finger, providing the high-intensity beam focusing in the large range of low energy of (3–50  MeV. Above 50 MeV we suggest using the slot structure with the external quadrupoles.

  11. High-linearity CMOS RF front-end circuits

    CERN Document Server

    Ding, Yongwang

    2005-01-01

    This monograph presents techniques to improve the performance of linear integrated circuits (IC) in CMOS at high frequencies. Those circuits are primarily used in radio-frequency (RF) front-ends of wireless communication systems, such as low noise amplifiers (LNA) and mixers in a receiver and power amplifiers (PA) in a transmitter. A novel linearization technique is presented. With a small trade-off of gain and power consumption this technique can improve the linearity of the majority of circuits by tens of dB. Particularly, for modern CMOS processes, most of which has device matching better than 1%, the distortion can be compressed by up to 40 dB at the output. A prototype LNA has been fabricated in a 0.25um CMOS process, with a measured +18 dBm IIP3. This technique improves the dynamic range of a receiver RF front-end by 12 dB. A new class of power amplifier (parallel class A&B) is also presented to extend the linear operation range and save the DC power consumption. It has been shown by both simulation...

  12. Autonomous Navigation Using Celestial Objects

    Science.gov (United States)

    Folta, David; Gramling, Cheryl; Leung, Dominic; Belur, Sheela; Long, Anne

    1999-01-01

    In the twenty-first century, National Aeronautics and Space Administration (NASA) Enterprises envision frequent low-cost missions to explore the solar system, observe the universe, and study our planet. Satellite autonomy is a key technology required to reduce satellite operating costs. The Guidance, Navigation, and Control Center (GNCC) at the Goddard Space Flight Center (GSFC) currently sponsors several initiatives associated with the development of advanced spacecraft systems to provide autonomous navigation and control. Autonomous navigation has the potential both to increase spacecraft navigation system performance and to reduce total mission cost. By eliminating the need for routine ground-based orbit determination and special tracking services, autonomous navigation can streamline spacecraft ground systems. Autonomous navigation products can be included in the science telemetry and forwarded directly to the scientific investigators. In addition, autonomous navigation products are available onboard to enable other autonomous capabilities, such as attitude control, maneuver planning and orbit control, and communications signal acquisition. Autonomous navigation is required to support advanced mission concepts such as satellite formation flying. GNCC has successfully developed high-accuracy autonomous navigation systems for near-Earth spacecraft using NASA's space and ground communications systems and the Global Positioning System (GPS). Recently, GNCC has expanded its autonomous navigation initiative to include satellite orbits that are beyond the regime in which use of GPS is possible. Currently, GNCC is assessing the feasibility of using standard spacecraft attitude sensors and communication components to provide autonomous navigation for missions including: libration point, gravity assist, high-Earth, and interplanetary orbits. The concept being evaluated uses a combination of star, Sun, and Earth sensor measurements along with forward-link Doppler

  13. The N456 Navigator System

    Science.gov (United States)

    2009-01-01

    acoustic navigation. Its two basic functions are generation of acoustic signals, and receipt and timing of returns. When combined with the new dsnav...system, the N456 timing functions are not used or affected. – 4 – 5. PRV Mode This is a common navigation method for the Jason/ Medea system. In...this mode, a trigger is sent down the tether, where it is causes an interrogation pulse from Medea . Boards dedicated to Medea and Jason both time the

  14. The navigation of space probes

    Science.gov (United States)

    Fliegel, H. F.; Ohandley, D. A.; Zielenbach, J. W.

    1974-01-01

    A new navigational method combining electronic measurement procedures and celestial mechanics makes it possible to conduct a space probe very close to a desired point in the neighborhood of a remote planet. Approaches for the determination of the position of the space probe in space are discussed, giving attention to the effects of errors in the employed data. The application of the navigational methods in a number of space missions is also considered.

  15. Modeling and simulation for RF system design

    CERN Document Server

    Frevert, Ronny; Jancke, Roland; Knöchel, Uwe; Schwarz, Peter; Kakerow, Ralf; Darianian, Mohsen

    2005-01-01

    Focusing on RF specific modeling and simulation methods, and system and circuit level descriptions, this work contains application-oriented training material. Accompanied by a CD- ROM, it combines the presentation of a mixed-signal design flow, an introduction into VHDL-AMS and Verilog-A, and the application of commercially available simulators.

  16. RF Circuit Design in Nanometer CMOS

    NARCIS (Netherlands)

    Nauta, Bram

    2007-01-01

    With CMOS technology entering the nanometer regime, the design of analog and RF circuits is complicated by low supply voltages, very non-linear (and nonquadratic) devices and large 1/f noise. At the same time, circuits are required to operate over increasingly wide bandwidths to implement modern

  17. Experimental study of rf pulsed heating

    Directory of Open Access Journals (Sweden)

    Lisa Laurent

    2011-04-01

    Full Text Available Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop®, copper silver, and silver plated copper. The samples were exposed to different machining and heat treatment processes prior to rf processing. Each sample was tested to a peak pulsed heating temperature of approximately 110°C and remained at this temperature for approximately 10×10^{6} rf pulses. In general, the results showed the possibility of pushing the gradient limits due to pulsed heating fatigue by the use of copper zirconium and copper chromium alloys.

  18. RF building block modeling: optimization and synthesis

    NARCIS (Netherlands)

    Cheng, W.

    2012-01-01

    For circuit designers it is desirable to have relatively simple RF circuit models that do give decent estimation accuracy and provide sufficient understanding of circuits. Chapter 2 in this thesis shows a general weak nonlinearity model that meets these demands. Using a method that is related to

  19. Commissioning of the MICE RF System

    CERN Document Server

    Moss, A.; Stanley, T.; White, C.; Ronald, K.; Whyte, C.G.; Dick, A.J.; Speirs, D.C.; Alsari, S.

    2014-01-01

    The Muon Ionisation Cooling Experiment (MICE) is being constructed at Rutherford Appleton Laboratory in the UK. The muon beam will be cooled using multiple hydrogen absorbers then reaccelerated using an RF cavity system operating at 201MHz. This paper describes recent progress in commissioning the amplifier systems at their design operation conditions, installation and operation as part of the MICE project.

  20. Higher-order mode rf guns

    Directory of Open Access Journals (Sweden)

    John W. Lewellen

    2001-04-01

    Full Text Available Traditional photocathode rf gun design is based around the use of TM_{0,1,0}-mode cavities. This is typically done in the interest of obtaining the highest possible gradient per unit supplied rf power and for historical reasons. In a multicell, aperture-coupled photoinjector, however, the gun as a whole is produced from strongly coupled cavities oscillating in a π mode. This design requires very careful preparation and tuning, as the field balance and resonant frequencies are easily disturbed. Side-coupled designs are often avoided because of the dipole modes introduced into the cavity fields. This paper proposes the use of a single higher-order mode rf cavity in order to generate the desired on-axis fields. It is shown that the field experienced by a beam in a higher-order mode rf gun is initially very similar to traditional 1.5- or 2.5-cell π-mode gun fields, and projected performance in terms of beam quality is also comparable. The new design has the advantages of much greater ease of fabrication, immunity from coupled-cell effects, and simpler tuning procedures. Because of the gun geometry, the possibility also exists for improved temperature stabilization and cooling for high duty-cycle applications.

  1. Prototype storage cavity for LEP accelerating RF

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The principle of an RF storage cavity was demonstrated with this prototype, working at 500 MHz. The final storage cavities were larger, to suit the LEP accelerating frequency of 352.2 MHz. Cu-tubes for watercooling are brazed onto the upper half, the lower half is to follow. See also 8006061, 8109346, 8407619X, and Annual Report 1980, p.115.

  2. Sources of Emittance in RF Photocathode Injectors

    Energy Technology Data Exchange (ETDEWEB)

    Dowell, David [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-11

    Advances in electron beam technology have been central to creating the current generation of x-ray free electron lasers and ultra-fast electron microscopes. These once exotic devices have become essential tools for basic research and applied science. One important beam technology for both is the electron source which, for many of these instruments, is the photocathode RF gun. The invention of the photocathode gun and the concepts of emittance compensation and beam matching in the presence of space charge and RF forces have made these high-quality beams possible. Achieving even brighter beams requires a taking a finer resolution view of the electron dynamics near the cathode during photoemission and the initial acceleration of the beam. In addition, the high brightness beam is more sensitive to degradation by the optical aberrations of the gun’s RF and magnetic lenses. This paper discusses these topics including the beam properties due to fundamental photoemission physics, space charge effects close to the cathode, and optical distortions introduced by the RF and solenoid fields. Analytic relations for these phenomena are derived and compared with numerical simulations.

  3. 47 CFR 101.1425 - RF safety.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false RF safety. 101.1425 Section 101.1425 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... safety. MVDDS stations in the 12.2-12.7 GHz frequency band do not operate with output powers that equal...

  4. European Frontiers in RF GaN

    NARCIS (Netherlands)

    Vliet, F.E. van; Hek, P. de

    2015-01-01

    In this overview paper, a summary of the European academic and industrial status on RF GaN is given. The roles of EDA and ESA are highlighted, and examples of on-going research activities are presented. A set of HPAs over frequency, representative of today's European status, is discussed. © 2015

  5. RF Voltage Measurements on ICRF Antennas

    Science.gov (United States)

    Bell, G. L.; Goulding, R. H.; Hoffman, D. J.; Wilgen, J. B.; Zhang, H. M.; Ryan, P. M.; Syed, G. M. S.; Kaye, A. S.

    1996-11-01

    Particle and heat flux on the plasma facing surfaces of high-power RF antennas used in fusion devices can result in damage to the antenna structures. High impedance capacitive probe measurements of the RF voltages on Faraday shields of several loop antennas indicate that voltages as high as 30% of the drive voltage can exist for 0/0 phasing (D.J. Hoffman, et al., AIP Conf. Proc. 355), 368 (Palm Spgs., CA, 1995).. These voltages can contribute to increased energy deposition on the antenna owing to increased RF sheath voltages. We report on continued efforts to understand the source and to control these RF voltages. E and B field distributions have been measured on the mock-up of the JET A2 antenna using standard B-dot probes and novel E-field probes positioned with a new automated scanning system. These data are compared with calculated fields from 3-D antenna models. The measurements demonstrate the dependency of the surface E-fields on the phasing of the strap currents and show the charge accumulation at the antenna top and bottom predicted by the models.

  6. RF Design of the LCLS Gun

    Energy Technology Data Exchange (ETDEWEB)

    Limborg-Deprey, C

    2010-12-13

    Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun [1], referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, dual rf feed, deformation tuning of the full cell, and field probes in both cells. Temporal shaping of the klystron pulse, to reduce the average power dissipated in the gun, has also been adopted. By increasing the mode separation, the amplitude of the 0-mode electric field on the cathode decreases from 10% of the peak on axis field for the prototype gun to less than 3% for the LCLS gun for the steady state fields. Beam performance is improved as shown by the PARMELA simulations. The gun should be designed to accept a future load lock system. Modifications follow the recommendations of our RF review committee [2]. Files and reference documents are compiled in Section IV.

  7. Status of RF superconductivity at Argonne

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.

    1989-01-01

    Development of a superconducting (SC) slow-wave structures began at Argonne National Laboratory (ANL) in 1971, and led to the first SC heavy-ion linac (ATLAS - the Argonne Tandem-Linac Accelerating System), which began regularly scheduled operation in 1978. To date, more than 40,000 hours of bean-on target operating time has been accumulated with ATLAS. The Physics Division at ANL has continued to develop SC RF technology for accelerating heavy-ions, with the result that the SC linac has, up to the present, has been in an almost continuous process of upgrade and expansion. It should be noted that this has been accomplished while at the same time maintaining a vigorous operating schedule in support of the nuclear and atomic physics research programs of the division. In 1987, the Engineering Physics Division at ANL began development of SC RF components for the acceleration of high-brightness proton and deuterium beams. This work has included the evaluation of RF properties of high-{Tc} oxide superconductors, both for the above and for other applications. The two divisions collaborated while they worked on several applications of RF SC, and also worked to develop the technology generally. 11 refs., 6 figs.

  8. Novel RF-MEMS capacitive switching structures

    NARCIS (Netherlands)

    Rottenberg, X.; Jansen, Henricus V.; Fiorini, P.; De Raedt, W.; Tilmans, H.A.C.

    2002-01-01

    This paper reports on novel RF-MEMS capacitive switching devices implementing an electrically floating metal layer covering the dielectric to ensure intimate contact with the bridge in the down state. This results in an optimal switch down capacitance and allows optimisation of the down/up

  9. Characterization of dielectric charging in RF MEMS

    NARCIS (Netherlands)

    Herfst, R.W.; Huizing, H.G.A.; Steeneken, P.G.; Schmitz, Jurriaan

    Capacitive RF MEMS switches show great promise for use in wireless communication devices such as mobile phones, but the successful application of these switches is hindered by the reliability of the devices: charge injection in the dielectric layer (SiN) can cause irreversible stiction of the moving

  10. RF MEMS Switches for Mobile Communication

    NARCIS (Netherlands)

    Steeneken, Peter; Herfst, R.W.; Suy, Hilco; Goossens, Martijn; van Beek, Joost; Bielen, Jeroen; Stulemeijer, Jiri; Schmitz, Jurriaan

    2008-01-01

    Switched capacitors based on radio frequency microelectromechanical systems (RF MEMS) can enable a breakthrough in radio technology. Their switching principle is based on the mechanical movement of the plates of a parallel plate capacitor using the electrostatic force. The resulting difference in

  11. RF Spectrum sensing in CMOS Exploiting Crosscorrelation

    NARCIS (Netherlands)

    Oude Alink, M.S.

    2013-01-01

    The introduction of new wireless services, the demand for higher datarates, and higher traffic volumes call for a more efficient use of the RF spectrum than what is currently possible with static frequency allocation. Dynamic spectrum access offers a more efficient use by allowing unlicensed users

  12. RF Anechoic Chambers, Tri-Service Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — In collaboration with the Navy, there are 12 RF Anechoic and static free exposure chambers located at TSRL. These chambers cover the majority of the RF spectrum and...

  13. Autonomous satellite navigation using starlight refraction angle measurements

    Science.gov (United States)

    Ning, Xiaolin; Wang, Longhua; Bai, Xinbei; Fang, Jiancheng

    2013-05-01

    An on-board autonomous navigation capability is required to reduce the operation costs and enhance the navigation performance of future satellites. Autonomous navigation by stellar refraction is a type of autonomous celestial navigation method that uses high-accuracy star sensors instead of Earth sensors to provide information regarding Earth's horizon. In previous studies, the refraction apparent height has typically been used for such navigation. However, the apparent height cannot be measured directly by a star sensor and can only be calculated by the refraction angle and an atmospheric refraction model. Therefore, additional errors are introduced by the uncertainty and nonlinearity of atmospheric refraction models, which result in reduced navigation accuracy and reliability. A new navigation method based on the direct measurement of the refraction angle is proposed to solve this problem. Techniques for the determination of the refraction angle are introduced, and a measurement model for the refraction angle is established. The method is tested and validated by simulations. When the starlight refraction height ranges from 20 to 50 km, a positioning accuracy of better than 100 m can be achieved for a low-Earth-orbit (LEO) satellite using the refraction angle, while the positioning accuracy of the traditional method using the apparent height is worse than 500 m under the same conditions. Furthermore, an analysis of the factors that affect navigation accuracy, including the measurement accuracy of the refraction angle, the number of visible refracted stars per orbit and the installation azimuth of star sensor, is presented. This method is highly recommended for small satellites in particular, as no additional hardware besides two star sensors is required.

  14. Rf beam control for the AGS Booster

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, J.M.

    1994-09-26

    RF beam control systems for hadron synchrotrons have evolved over the past three decades into an essentially standard design. The key difference between hadron and lepton machines is the absence of radiation damping and existence of significant frequency variation in the case of hadrons. Although the motion of the hadron in the potential well of the rf wave is inherently stable it is not strongly damped. Damping must be provided by electronic feedback through the accelerating system. This feedback is typically called the phase loop. The technology of the rf beam control system for the AGS Booster synchrotron is described. First, the overall philosophy of the design is explained in terms of a conventional servo system that regulates the beam horizontal position in the vacuum chamber. The concept of beam transfer functions is fundamental to the mathematics of the design process and is reviewed. The beam transfer functions required for this design are derived from first principles. An overview of the beam signal pick-ups and high level rf equipment is given. The major subsystems, the frequency program, the heterodyne system, and beam feedback loops, are described in detail. Beyond accelerating the beam, the rf system must also synchronize the bunches in the Booster to the buckets in the AGS before transfer. The technical challenge in this process is heightened by the need to accomplish synchronization while the frequency is still changing. Details of the synchronization system are given. This report is intended to serve two purposes. One is to document the hardware and performance of the systems that have been built. The other is to serve as a tutorial vehicle from which the non-expert can not only learn the details of this system but also learn the principles of beam control that have led to the particular design choices made.

  15. Facilitating Performance Optimization of RF PCB Designs by using Parametric Finite-Element Component Models

    DEFF Research Database (Denmark)

    Rohde, John; Toftegaard, Thomas Skjødeberg

    2012-01-01

    Novel parametric finite-element models are provided for discrete SMD capacitors and inductors in the frequency range 100 MHz to 4 GHz. The aim of the models is to facilitate performance optimization and analysis of RF PCB designs integrating these SMD components with layout geometries such as ant...

  16. Personality and psychopathology: Mapping the MMPI-2-RF on Cloninger's Psychobiological Model of Personality

    NARCIS (Netherlands)

    Heijden, P.T. van der; Egger, J.I.M.; Rossi, G.M.P.; Veld, W.M. van der; Derksen, J.J.L.

    2013-01-01

    This study investigates the relationship between the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) and the Temperament and Character Inventory (TCI) in a combined data set (N = 491) of patients with a broad range of psychiatric disorders (n = 286) as well as alcohol use

  17. Personality and psychopathology: mapping the MMPI-2-RF on Cloninger's psychobiological model of personality.

    Science.gov (United States)

    van der Heijden, Paul T; Egger, Jos I M; Rossi, Gina M P; van der Veld, William M; Derksen, Jan J L

    2013-10-01

    This study investigates the relationship between the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) and the Temperament and Character Inventory (TCI) in a combined data set (N = 491) of patients with a broad range of psychiatric disorders (n = 286) as well as alcohol use disorder (n = 205). We examined bivariate correlations between both measures. The MMPI-2-RF scales relate to the TCI dimensions as was hypothesized, and relationships between both measurements were largely similar for psychiatric patients and alcohol-dependent patients. Theoretical and clinical implications are considered.

  18. Advances in analog and RF IC design for wireless communication systems

    CERN Document Server

    Manganaro, Gabriele

    2013-01-01

    Advances in Analog and RF IC Design for Wireless Communication Systems gives technical introductions to the latest and most significant topics in the area of circuit design of analog/RF ICs for wireless communication systems, emphasizing wireless infrastructure rather than handsets. The book ranges from very high performance circuits for complex wireless infrastructure systems to selected highly integrated systems for handsets and mobile devices. Coverage includes power amplifiers, low-noise amplifiers, modulators, analog-to-digital converters (ADCs) and digital-to-analog converters

  19. RF subsystem power consumption and induced radiation emulation

    DEFF Research Database (Denmark)

    Musiige, Deogratius; Anton, François; Mioc, Darka

    the study of the RF subsystem architectures revealed numerous architectures with different impacts on power consumption, we have decided to consider the RF subsystem as a black box. The RF subsystem power emulation has been studied for the telecommunication technology Long Term Evolusion (LTE). Given...

  20. Study of Control Grid Thermionic Cathode RF Gun

    CERN Document Server

    Xiao, Jin; Ming, Li; Xinfan, Yang; Xumin, Shen; Yanan, Chen; Zhou, Xu

    2004-01-01

    In this paper, the beam loading effect of RF Gun was analyzed. To minimize the energy spread, the grid control RF Gun was introduced. The result shows that the grid congrol RF Gun can increase electron beam within 1% energy spread.

  1. Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) predictors of police officer problem behavior.

    Science.gov (United States)

    Tarescavage, Anthony M; Corey, David M; Ben-Porath, Yossef S

    2015-02-01

    The purpose of this study was to investigate the predictive validity of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) in a sample of law enforcement officers. MMPI-2-RF scores were collected from preemployment psychological evaluations of 136 male police officers, and supervisor ratings of performance and problem behavior were subsequently obtained during the initial probationary period. The sample produced meaningfully lower and less variant substantive scale scores than the general population and the MMPI-2-RF Police Candidate comparison group, which significantly affected effect sizes for the zero-order correlations. After applying a correction for range restriction, MMPI-2-RF substantive scales demonstrated moderate to strong associations with criteria, particularly in the Emotional Dysfunction and Interpersonal Functioning domains. Relative risk ratio analyses showed that cutoffs of 45T and 50T maintained reasonable selection ratios because of the exceptionally low scores in this sample and were associated with significantly increased risk for problematic behavior. These results provide support for the predictive validity of the MMPI-2-RF substantive scales in this setting. Implications of these findings and limitations of these results are discussed. © The Author(s) 2014.

  2. Using Signal Envelope Detection for Online and Offline RF MEMS Switch Testing

    Directory of Open Access Journals (Sweden)

    E. Simeu

    2008-01-01

    Full Text Available The test of radiofrequency (RF integrated circuits at their ever-increasing operating frequency range requires sophisticated test equipment and is time-consuming and, therefore, very expensive. This paper introduces a new method combining low-frequency actuation signal as test stimuli and signal envelope detection applied on the RF output signal in order to provide a low-cost mean for production testing of RF MEMS switches embedded in system-in-package (SiP devices. The proposed approach uses the principle of alternate test that replaces conventional specification-based testing procedures. The basic idea is to extract the high-frequency characteristics of the switch from the signal envelope of the response. Output parameters like “on” and “off” transition time are extracted at low frequency and used in a regression process to predict RF conventional specifications like S-parameters. The paper also provides a set of recursive estimation algorithms suitable for online testing. In this context, “on” and “off” transition time estimated from the output low-frequency envelope is used as test metrics and is concurrently updated using recursive algorithms. Validation results obtained on a capacitive RF switch model are presented.

  3. Multi-cell disk-and-ring tapered structure for compact RF linacs

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.V.; Boucher, S.; Kutsaev, S. [RadiaBeam Systems LLC, 1713 Stewart Street, Santa Monica, CA 90404, US (United States); Hartzell, J. [RadiaBeam Technologies, LLC, 1717 Stewart Street, Santa Monica, CA 90404, US (United States); Savin, E. [RadiaBeam Technologies, LLC, 1717 Stewart Street, Santa Monica, CA 90404, US (United States); National Research Nuclear University “MEPhI”, Moscow 115409 (Russian Federation)

    2016-09-11

    A tubular disk-and-ring, tapered accelerating structure for small electron linacs and MicroLinacs is considered. It consists of metal and dielectric elements inserted into a metallic tube to eliminate multi-cell, multi-step brazing. The structure enables a wide range of phase velocities (including non-relativistic), a wide bandwidth allowing large number of cells (for standing wave mode) or short filling time (for traveling wave mode), combination of compensated and purely π-mode cells, alternative periodic focusing built-in to the RF structure (the disks), and combining of RF and vacuum windows. RF and accelerating performance of such a long structure having up to four dozens cells is analyzed. Some of beam dynamics, thermal, and vacuum aspects of the structure and MicroLinac performance are considered as well.

  4. Design Concepts for RF-DC Conversion in Particle Accelerator Systems

    CERN Document Server

    Caspers, F; Grudiev, A; Sapotta, H

    2010-01-01

    In many particle accelerators considerable amounts of RF power reaching the megawatt level are converted into heat in dummy loads. After an overview of RF power in the range 200 MHz to 1 GHz dissipated at CERN we discuss several developments that have come up in the past using vacuum tube technology for RF-DC conversion. Amongst those the developments of the cyclotron wave converter CWC appears most suitable. With the availability of powerful Schottky diodes the solid state converter aspect has to be addressed as well. One of the biggest problems of Schottky diode based structures is the junction capacity. GaAs and GaN Schottky diodes show a significant reduction of this junction capacity as compared to silicon. Small rectenna type converter units which have been already developed for microwave powered helicopters can be used in waveguides or with coaxial power dividers.

  5. Compact autonomous navigation system (CANS)

    Science.gov (United States)

    Hao, Y. C.; Ying, L.; Xiong, K.; Cheng, H. Y.; Qiao, G. D.

    2017-11-01

    Autonomous navigation of Satellite and constellation has series of benefits, such as to reduce operation cost and ground station workload, to avoid the event of crises of war and natural disaster, to increase spacecraft autonomy, and so on. Autonomous navigation satellite is independent of ground station support. Many systems are developed for autonomous navigation of satellite in the past 20 years. Along them American MANS (Microcosm Autonomous Navigation System) [1] of Microcosm Inc. and ERADS [2] [3] (Earth Reference Attitude Determination System) of Honeywell Inc. are well known. The systems anticipate a series of good features of autonomous navigation and aim low cost, integrated structure, low power consumption and compact layout. The ERADS is an integrated small 3-axis attitude sensor system with low cost and small volume. It has the Earth center measurement accuracy higher than the common IR sensor because the detected ultraviolet radiation zone of the atmosphere has a brightness gradient larger than that of the IR zone. But the ERADS is still a complex system because it has to eliminate many problems such as making of the sapphire sphere lens, birefringence effect of sapphire, high precision image transfer optical fiber flattener, ultraviolet intensifier noise, and so on. The marginal sphere FOV of the sphere lens of the ERADS is used to star imaging that may be bring some disadvantages., i.e. , the image energy and attitude measurements accuracy may be reduced due to the tilt image acceptance end of the fiber flattener in the FOV. Besides Japan, Germany and Russia developed visible earth sensor for GEO [4] [5]. Do we have a way to develop a cheaper/easier and more accurate autonomous navigation system that can be used to all LEO spacecraft, especially, to LEO small and micro satellites? To return this problem we provide a new type of the system—CANS (Compact Autonomous Navigation System) [6].

  6. Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (R-F) ion-exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Bryan, S.A.; Hallen, R.T.; Brown, G.N.; Bray, L.A.; Linehan, J.C.

    1995-08-01

    The 177 underground storage tanks at the DOE`s Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a 1,2,4-trisubstituted ring. CS-100 shows the presence of phenoxy-ether groups, and this may account for the much lower decontamination factor of CS-100 for cesium ion. Curing temperatures for the R-F resin were found to be optimal at 105--130C. At lower temperatures, insufficient curing, hence crosslinking, of the polymer resin occurs and selectivity for cesium drops. Curing at elevated temperatures leads to chemical degradation. Optimal particle size for R-F resin is in the range of 20--50 mesh-sized particles. R-F resin undergoes chemical degradation or oxidation which destroys ion-exchange sites. The ion-exchange sites (hydroxyl groups) are converted to quinones and ketones. CS-100, though it has much lower performance for cesium ion-exchange, is significantly more chemically stable than R-F resin. To gamma radiation, CS-100 is more radiolytically stable than R-F resin.

  7. Navigation and geo-tracking system of UAV EO payload

    Science.gov (United States)

    Chen, Ying; Zhen, Kang; Xue, Yuanyuan; Zhang, Xiajiang; Li, Yingjuan; Tang, Chao

    2016-01-01

    A multi-function system based on inertial measurement unit (IMU) is introduced, which can fulfill navigation, attitude measurement of LOS in payload, platform stabilization and tracking control. The IMU is integrated with electro-optical sensors and a laser range finder on gimbals, which performs attitude calculation and navigation by constructing navigation coordinates in a mathematic platform, and the platform navigation information is obtained by transformation matrix between platform and gimbal coordinates. The platform comprising of gyros, electro-optical sensors and servo mechanism is capable of stabilizing line of sight and could be used to geo-tracking in the relevant field of view (FOV).The system can determine geography coordinates of the host platform and target only with navigation information and laser ranging data. The geo-tracking system always locked the target image at the center of FOV by calculating spatial geometry and adjusting LOS attitude. This tracking is different from TV tracking and geographical reference image tracking, which may be influenced by fog and obscurant. When the UAV is flying over urban or mountain areas for rescue missions, it can avoid the loss of targets due to strong maneuver or LOS obscuration, and reduce the operation load and improve rescue efficiency.

  8. 33 CFR 401.54 - Interference with navigation aids.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...

  9. Modelling group navigation: transitive social structures improve navigational performance.

    Science.gov (United States)

    Flack, Andrea; Biro, Dora; Guilford, Tim; Freeman, Robin

    2015-07-06

    Collective navigation demands that group members reach consensus on which path to follow, a task that might become more challenging when the group's members have different social connections. Group decision-making mechanisms have been studied successfully in the past using individual-based modelling, although many of these studies have neglected the role of social connections between the group's interacting members. Nevertheless, empirical studies have demonstrated that individual recognition, previous shared experiences and inter-individual familiarity can influence the cohesion and the dynamics of the group as well as the relative spatial positions of specific individuals within it. Here, we use models of collective motion to study the impact of social relationships on group navigation by introducing social network structures into a model of collective motion. Our results show that groups consisting of equally informed individuals achieve the highest level of accuracy when they are hierarchically organized with the minimum number of preferred connections per individual. We also observe that the navigational accuracy of a group will depend strongly on detailed aspects of its social organization. More specifically, group navigation does not only depend on the underlying social relationships, but also on how much weight leading individuals put on following others. Also, we show that groups with certain social structures can compensate better for an increased level of navigational error. The results have broader implications for studies on collective navigation and motion because they show that only by considering a group's social system can we fully elucidate the dynamics and advantages of joint movements. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  10. Plasma properties of RF magnetron sputtering system using Zn target

    Energy Technology Data Exchange (ETDEWEB)

    Nafarizal, N.; Andreas Albert, A. R.; Sharifah Amirah, A. S.; Salwa, O.; Riyaz Ahmad, M. A. [Microelectronic and Nanotechnology - Shamsuddin Research Centre (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

    2012-06-29

    In the present work, we investigate the fundamental properties of magnetron sputtering plasma using Zn target and its deposited Zn thin film. The magnetron sputtering plasma was produced using radio frequency (RF) power supply and Argon (Ar) as ambient gas. A Langmuir probe was used to collect the current from the plasma and from the current intensity, we calculate the electron density and electron temperature. The properties of Zn sputtering plasma at various discharge conditions were studied. At the RF power ranging from 20 to 100 W and gas pressure 5 mTorr, we found that the electron temperature was almost unchanged between 2-2.5 eV. On the other hand, the electron temperature increased drastically from 6 Multiplication-Sign 10{sup 9} to 1 Multiplication-Sign 10{sup 10}cm{sup -3} when the discharge gas pressure increased from 5 to 10 mTorr. The electron microscope images show that the grain size of Zn thin film increase when the discharge power is increased. This may be due to the enhancement of plasma density and sputtered Zn density.

  11. Application of rf plasma for treatment of wool

    Science.gov (United States)

    Radetić, M.; Jović, D.; JovančiĆ, P.; Petrović, Z. Lj.

    1999-10-01

    Capacitively coupled rf plasma was used to treat wool fabrics. We have used pressures in the range of 0.25-0.75 mbar and powers of the order of 100 W. The rf plasma chamber was cylindrical and the central electrode was powered making it a very asymmetric system. The wool fibers were placed on the outer chamber walls which have the radius of 35 cm and which were grounded. The treatment lasted between 0 and 10 minutes in air, oxygen and argon 13.56 MHz plasmas. Even after 2 minutes the properties of the wool have changed sufficiently to match the treatment by chlorination as far as the quality of printing and dyeing goes. In addition fiber swelling, pilling and wettability were also considerably improved. Extended treatment by plasma reduces mechanical properties of wool fibers so limited duration of treatment of 2-5 minutes in oxygen was found to give optimum results. Topography of the fibers was analyzed by using atomic force microscopy and scanning electron microscopy. It was discovered that the improvement was brought about by superficial modification of the fiber through replacement of the fatty layer and partial destruction of the epicuticle.

  12. Physics and technology of silicon RF power devices

    CERN Document Server

    Cao, G

    2000-01-01

    can be increased by optimising the drift and epi-layer design, higher power can be delivered without increasing the input capacitance and feedback capacitance. first time, it is identified that the intrinsic MOSFET is the dominant component in the RF LDMOSFET, which ensures the saturation property in forward I-V characteristics. Detailed results are presented on the transconductance performance of the device. It is clarified that the fall-off of transconductance of a RF LDMOSFET is caused jointly by the high resistance of this region and the reduction in channel resistance at a high gate voltage. Because of these two factors, most of the potential is dropped across the drift region at a high gate bias. As a result, the intrinsic MOSFET is forced into its linear region of operation, which results in a fall-off of the transconductance. To increase the range of gate voltages for a constant transconductance, higher drift doping concentration is preferred. This can be achieved by incorporating a grounded field pla...

  13. Superconducting rf development at ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kedzie, M.; Clifft, B.E. [Argonne National Lab., IL (United States); Roy, A.; Potukuchi, P. [Nuclear Science Centre, New Delhi (India); Givens, J.; Potter, J.; Crandall, K. [AccSys Technology, Inc., Pleasanton, CA (United States); Added, N. [Sao Paulo Univ., SP (Brazil)

    1993-12-31

    The ATLAS superconducting heavy-ion linac began operation in 1978 and has operated nearly continuously since that time, while undergoing a series of upgrades and expansions, the most recent being the ``uranium upgrade`` completed earlier this year and described below. In its present configuration the ATLAS linac consists of an array of 64 resonant cavities operating from 48 to 145 MHz, which match a range of particle velocities .007 < {beta} = v/c < .2. The linac provides approximately 50 MV of effective accelerating potential for ions of q/m > 1/10 over the entire periodic table. Delivered beams include 5 {minus} 7 pnA of {sup 238}U{sup 39+} at 1535 MeV. At present more than 10{sup 6} cavity-hours of operation at surface electric fields of 15 MV/m have been accumulated. Superconducting structure development at ATLAS is aimed at improving the cost/performance of existing low velocity structures both for possible future ATLAS upgrades, and also for heavy-ion linacs at other institutions. An application of particular current interest is to develop structures suitable for accelerating radioactive ion beams. Such structures must accelerate very low charge to mass ratio beams and must also have very large transverse acceptance.

  14. RF Communication Subsystem Integration Research

    Science.gov (United States)

    2010-10-15

    range w round in a g .11a WLAN w r on‐chip an le. However ip antenna i na is based   low tempe 4]‐[26].  Hen  than that tr nna. As me ll package su...red      g the  r of    ~1‐2 µW  that of an Ideally, t sufficient and,  hen typically  an RF‐to‐ metal ca concern f controlle tuning fr than ‐10...tenna port.  tal  parasitic d,p+, (where t the DC out  side and vd e, the diode witch is sho a NOR gate  ne branch o el devices th duce the p  the two sig

  15. Global navigation satellite systems, inertial navigation, and integration

    CERN Document Server

    Grewal, Mohinder S; Bartone, Chris G

    2013-01-01

    An updated guide to GNSS, and INS, and solutions to real-world GNSS/INS problems with Kalman filtering Written by recognized authorities in the field, this third edition of a landmark work provides engineers, computer scientists, and others with a working familiarity of the theory and contemporary applications of Global Navigation Satellite Systems (GNSS), Inertial Navigational Systems, and Kalman filters. Throughout, the focus is on solving real-world problems, with an emphasis on the effective use of state-of-the-art integration techniques for those systems, especially the application of Kal

  16. Rare Variants in Genes Encoding MuRF1 and MuRF2 Are Modifiers of Hypertrophic Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Ming Su

    2014-05-01

    Full Text Available Modifier genes contribute to the diverse clinical manifestations of hypertrophic cardiomyopathy (HCM, but are still largely unknown. Muscle ring finger (MuRF proteins are a class of muscle-specific ubiquitin E3-ligases that appear to modulate cardiac mass and function by regulating the ubiquitin-proteasome system. In this study we screened all the three members of the MuRF family, MuRF1, MuRF2 and MuRF3, in 594 unrelated HCM patients and 307 healthy controls by targeted resequencing. Identified rare variants were confirmed by capillary Sanger sequencing. The prevalence of rare variants in both MuRF1 and MuRF2 in HCM patients was higher than that in control subjects (MuRF1 13/594 (2.2% vs. 1/307 (0.3%, p = 0.04; MuRF2 22/594 (3.7% vs. 2/307 (0.7%; p = 0.007. Patients with rare variants in MuRF1 or MuRF2 were younger (p = 0.04 and had greater maximum left ventricular wall thickness (p = 0.006 than those without such variants. Mutations in genes encoding sarcomere proteins were present in 19 (55.9% of the 34 HCM patients with rare variants in MuRF1 and MuRF2. These data strongly supported that rare variants in MuRF1 and MuRF2 are associated with higher penetrance and more severe clinical manifestations of HCM. The findings suggest that dysregulation of the ubiquitin-proteasome system contributes to the pathogenesis of HCM.

  17. Modeling and Manufacturing of Micromechanical RF Switch with Inductors

    Directory of Open Access Journals (Sweden)

    Ying-Liang Chen

    2007-11-01

    Full Text Available This study presents the simulation, fabrication and characterization ofmicromechanical radio frequency (RF switch with micro inductors. The inductors areemployed to enhance the characteristic of the RF switch. An equivalent circuit model isdeveloped to simulate the performance of the RF switch. The behaviors of themicromechanical RF switch are simulated by the finite element method software,CoventorWare. The micromechanical RF switch is fabricated using the complementarymetal oxide semiconductor (CMOS and a post-process. The post-process employs a wetetching to etch the sacrificial layer, and to release the suspended structures of the RF switch.The structure of the RF switch contains a coplanar waveguide (CPW, a suspendedmembrane, eight springs and two inductors in series. Experimental results reveal that theinsertion loss and isolation of the switch are 1.7 dB at 21 GHz and 19 dB at 21 GHz,respectively. The driving voltage of the switch is about 13 V.

  18. Differential Bearing Estimation for RF Tags

    Directory of Open Access Journals (Sweden)

    Lédeczi Ákos

    2009-01-01

    Full Text Available Fusing spatially distributed observations in wireless sensor networks or asset tracking in a shipyard are just two-example applications where the location of radio nodes needs to be known. Localization and tracking of wireless nodes have been an active research area, yet a universal solution has not emerged so far. This paper introduces a novel method for bearing estimation based on a rotating antenna generating a Doppler shifted RF signal. The small frequency change can be measured even on low-cost resource constrained nodes using a radio interferometric technique introduced previously. Bearing information between anchors nodes at known locations and RF tags at unknown positions can be derived. A few such measurements provide enough information to enable accurate node localization.

  19. Cognitive Radio RF: Overview and Challenges

    Directory of Open Access Journals (Sweden)

    Van Tam Nguyen

    2012-01-01

    Full Text Available Cognitive radio system (CRS is a radio system which is aware of its operational and geographical environment, established policies, and its internal state. It is able to dynamically and autonomously adapt its operational parameters and protocols and to learn from its previous experience. Based on software-defined radio (SDR, CRS provides additional flexibility and offers improved efficiency to overall spectrum use. CRS is a disruptive technology targeting very high spectral efficiency. This paper presents an overview and challenges of CRS with focus on radio frequency (RF section. We summarize the status of the related regulation and standardization activities which are very important for the success of any emerging technology. We point out some key research challenges, especially implementation challenges of cognitive radio (CR. A particular focus is on RF front-end, transceiver, and analog-to-digital and digital-to-analog interfaces which are still a key bottleneck in CRS development.

  20. SPS RF System an Accelerating Cavity

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X.

  1. Aluminum nitride for heatspreading in RF IC's

    Science.gov (United States)

    La Spina, L.; Iborra, E.; Schellevis, H.; Clement, M.; Olivares, J.; Nanver, L. K.

    2008-09-01

    To reduce the electrothermal instabilities in silicon-on-glass high-frequency bipolar devices, the integration of thin-film aluminum nitride as a heatspreader is studied. The AlN is deposited by reactive sputtering and this material is shown to fulfill all the requirements for actively draining heat from RF IC's, i.e., it has good process compatibility, sufficiently high thermal conductivity and good electrical isolation also at high frequencies. The residual stress and the piezoelectric character of the material, both of which can be detrimental for the present application, are minimized by a suitable choice of deposition conditions including variable biasing of the substrate in a multistep deposition cycle. Films of AlN as thick as 4 μm are successfully integrated in RF silicon-on-glass bipolar junction transistors that display a reduction of more than 70% in the value of the thermal resistance.

  2. PEP-II RF cavity revisited

    Energy Technology Data Exchange (ETDEWEB)

    Rimmer, R.A.; Koehler, G.; Li, D.; Hartman, N.; Folwell, N.; Hodgson, J.; Ko, K.; McCandless, B.

    1999-11-01

    This report describes the results of numerical simulations of the PEP-II RF cavity performed after the completion of the construction phase of the project and comparisons are made to previous calculations and measured results. These analyses were performed to evaluate new calculation techniques for the HOM distribution and RF surface heating that were not available at the time of the original design. These include the use of a high frequency electromagnetic element in ANSYS and the new Omega 3P code to study wall losses, and the development of broadband time domain simulation methods in MAFIA for the HOM loading. The computed HOM spectrum is compared with cavity measurements and observed beam-induced signals. The cavity fabrication method is reviewed, with the benefit of hindsight, and simplifications are discussed.

  3. Experimental study of rf pulsed heating

    CERN Document Server

    Laurent, L; Nantista, C; Dolgashev, V; Higashi, Y; Aicheler, M; Tantawi, S; Wuensch, W

    2011-01-01

    Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on the attainable reliable gradients for room temperature linear accelerators. This is especially true for structures that have complicated features for wakefield damping. These limits could be pushed higher by using special types of copper, copper alloys, or other conducting metals in constructing partial or complete accelerator structures. Here we present an experimental study aimed at determining the potential of these materials for tolerating cyclic thermal fatigue due to rf magnetic fields. A special cavity that has no electric field on the surface was employed in these studies. The cavity shape concentrates the magnetic field on one flat surface where the test material is placed. The materials tested in this study have included oxygen free electronic grade copper, copper zirconium, copper chromium, hot isostatically pressed copper, single crystal copper, electroplated copper, Glidcop (R), copper silver, and silver plated co...

  4. Superconducting RF separator for Omega Spectrometer

    CERN Multimedia

    1977-01-01

    The photo shows an Nb-deflector for the superconducting RF separator ready for installation in its cryostat (visible at the back). Each deflector was about 3 m long. L. Husson and P. Skacel (Karlsruhe) stand on the left, A. Scharding (CERN) stands on the right. This particle separator, the result of a collaboration between the Gesellshaft für Kernforschung, Karlsruhe, and CERN was installed in the S1 beam line to Omega spectrometer. (See Annual Report 1977.)

  5. At the RF Lab, EF Division

    CERN Multimedia

    1980-01-01

    A four-cell superconducting RF cavity ready for installation in its cryostat, the first one at CERN. From bottom to top, on the right, Herbert Lengeler, Jean-François Malo, Enrico Chiaveri and François Grabowski, Albert Insomby. On the left, ..?, Ernst Ullrich Haebel, ..?, Jean-Marie Maugain, Artur Scharding, Hansuli Preis, R. Romjin. The place is the EF hall next to Bld. 13. (see Annual Report 1980 p. 71)

  6. Phase Noise in RF and Microwave Amplifiers

    OpenAIRE

    Boudot, Rodolphe; Rubiola, Enrico

    2010-01-01

    Understanding the amplifier phase noise is a critical issue in numerous fields of engineering and physics, like oscillators, frequency synthesis, telecommunications, radars, spectroscopy, in the emerging domain of microwave photonics, and in more exotic domains like radio astronomy, particle accelerators, etc. This article analyzes the two main types of phase noise in amplifiers, white and flicker. White phase noise results from adding white noise to the RF spectrum around the carrier. For a ...

  7. RF separator for cloud muons at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Blackmore, E.W.; Bryman, D.A.; Cresswell, J.V.; Doornbos, J.; Erdman, K.L.; MacDonald, J.A.; Poirier, R.L.; Pearce, R.M.; Poutissou, J.M.; Spuller, J. (British Columbia Univ., Vancouver (Canada). TRIUMF Facility)

    1985-02-01

    A particle separator utilizing crossed magnetic and RF electric fields has been incorporated into the TRIUMF M9 secondary channel to produce a clean negative muon beam at 77 MeV/c+-5%. The separator is driven at the main cyclotron frequency (23 MHz) and phase locked to the primary proton beam. The pion and electron contaminants in the beam are suppressed to <0.1% and <1%, respectively.

  8. RF separator for cloud muons at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Blackmore, E.W.; Bryman, D.A.; Cresswell, J.V.; Doornbos, J.; Erdman, K.L.; MacDonald, J.A.; Poirier, R.L.; Pearce, R.M.; Poutissou, J.M.; Spuller, J.

    1985-02-01

    A particle separator utilizing crossed magnetic and RF electric fields has been incorporated into the TRIUMF M9 secondary channel to produce a clean negative muon beam at 77 MeV/c +- 5%. The separator is driven at the main cyclotron frequency (23 MHz) and phase locked to the primary proton beam. The pion and electron contaminants in the beam are suppressed to <0.1% and <1%, respectively. (orig.).

  9. Modeling accelerator structures and RF components

    Energy Technology Data Exchange (ETDEWEB)

    Ko, K., Ng, C.K.; Herrmannsfeldt, W.B.

    1993-03-01

    Computer modeling has become an integral part of the design and analysis of accelerator structures RF components. Sophisticated 3D codes, powerful workstations and timely theory support all contributed to this development. We will describe our modeling experience with these resources and discuss their impact on ongoing work at SLAC. Specific examples from R&D on a future linear collide and a proposed e{sup +}e{sup {minus}} storage ring will be included.

  10. NSLS-II RF Cryogenic System

    Energy Technology Data Exchange (ETDEWEB)

    Rose, J.; Dilgen, T.; Gash, B.; Gosman, J.; Mortazavi, P.; Papu, J.; Ravindranath, V.; Sikora, R.; Sitnikov, A.; Wilhelm, H.; Jia, Y.; Monroe, C.

    2015-05-03

    The National Synchrotron Light Source II is a 3 GeV X-ray user facility commissioned in 2014. A new helium refrigerator system has been installed and commissioned to support the superconducting RF cavities in the storage ring. Special care was taken to provide very stable helium and LN2 pressures and flow rates to minimize microphonics and thermal effects at the cavities. Details of the system design along with commissioning and early operations data will be presented.

  11. RF transmission lines on silicon substrates

    OpenAIRE

    Ponchak, George E.

    1999-01-01

    A review of RF transmission lines on silicon substrates is presented. Through measurements and calculated results, it is shown that attenuation is dominated by conductor loss if silicon substrates with a resistivity greater than 2500 Q-cm are used. Si passivation layers affect the transmission line attenuation; however, measured results demonstrate that passivation layers do not necessarily increase attenuation. If standard, low resistivity Si wafers must be used, alternative transmission lin...

  12. Wireless RF communication in biomedical applications

    Science.gov (United States)

    Jones, Inke; Ricciardi, Lucas; Hall, Leonard; Hansen, Hedley; Varadan, Vijay; Bertram, Chris; Maddocks, Simon; Enderling, Stefan; Saint, David; Al-Sarawi, Said; Abbott, Derek

    2008-02-01

    This paper focuses on wireless transcutaneous RF communication in biomedical applications. It discusses current technology, restrictions and applications and also illustrates possible future developments. It focuses on the application in biotelemetry where the system consists of a transmitter and a receiver with a transmission link in between. The transmitted information can either be a biopotential or a nonelectric value like arterial pressure, respiration, body temperature or pH value. In this paper the use of radio-frequency (RF) communication and identification for those applications is described. Basically, radio-frequency identification or RFID is a technology that is analogous to the working principle of magnetic barcode systems. Unlike magnetic barcodes, passive RFID can be used in extreme climatic conditions—also the tags do not need to be within close proximity of the reader. Our proposed solution is to exploit an exciting new development in making circuits on polymers without the need for battery power. This solution exploits the principle of a surface acoustic wave (SAW) device on a polymer substrate. The SAW device is a set of interdigitated conducting fingers on the polymer substrate. If an appropriate RF signal is sent to the device, the fingers act as microantennas that pick up the signal, and this energy is then converted into acoustic waves that travel across the surface of the polymer substrate. Being a flexible polymer, the acoustic waves cause stresses that can either contract or stretch the material. In our case we mainly focus on an RF controllable microvalve that could ultimately be used for fertility control.

  13. Wearable Navigation Assistance - A tool for the blind

    OpenAIRE

    van der Heijden, Ferdinand; Regtien, Paulus P.L.

    2005-01-01

    This paper describes the system architecture for a navigation tool for visually impaired persons. The major parts are: a multi-sensory system (comprising stereo vision, acoustic range finding and movement sensors), a mapper, a warning system and a tactile human-machine interface. The sensory parts are described in more detail, and the first experimental results are presented.

  14. Wearable Navigation Assistance - A tool for the blind

    NARCIS (Netherlands)

    van der Heijden, Ferdinand; Regtien, Paulus P.L.

    2005-01-01

    This paper describes the system architecture for a navigation tool for visually impaired persons. The major parts are: a multi-sensory system (comprising stereo vision, acoustic range finding and movement sensors), a mapper, a warning system and a tactile human-machine interface. The sensory parts

  15. Wearable navigation assistance - A tool for the blind

    NARCIS (Netherlands)

    van der Heijden, Ferdinand; Regtien, Paulus P.L.

    2005-01-01

    This paper describes the system architecture for a navigation tool for visually impaired persons. The major parts are: a multi-sensory system (comprising stereo vision, acoustic range finding and movement sensors), a mapper, a warning system and a tactile human-machine interface. The sensory parts

  16. The Murmansk Initiative - RF: Acceptance Testing

    Energy Technology Data Exchange (ETDEWEB)

    Czajkowski, C.; Wester, D. W.; Dyer, R. S.; Soerlie, A. A.; Moller, B.; Barnes, E.

    2002-02-26

    The Murmansk Initiative-RF (MI) was conceived to provide the Russian Federation (RF) with the capacity to manage low-level liquid radioactive waste (LLRW) and comply with the requirements of the London Convention that prohibit ocean dumping. The trilateral project among Norway, the RF, and the United States of America (U.S.) began in 1994 and was the first to utilize exclusively Russian subcontractors to upgrade and expand an existing LLRW treatment plant on the premises of RTP Atomflot in Murmansk, Russia. The project moved quickly through the design phase. Progress during the construction phase was somewhat slower because of difficulties with acquisition of hardware, inexperience with automated instrumentation and control equipment, and unexpected design changes in the cementation unit. The project advanced into the test-operation phase, which is currently underway, in June 2001. Initial runs with liquid waste have revealed that procedures for unloading spent ion-exchange sorbents could be improved and that sludges formed during removal of alkaline-earth metals should be compacted in order for the facility to operate at its full potential. Resolution of these issues is expected within the next few months.

  17. SPS RF system:Tetrodes and waveguides

    CERN Multimedia

    1974-01-01

    This picture shows one of the initially installed amplifier units of the SPS RF system. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: in 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X.

  18. RF Gun Photocathode Research at SLAC

    Energy Technology Data Exchange (ETDEWEB)

    Jongewaard, E.; Akre, R.; Brachmann, A.; Corbett, J.; Gilevich, S.; Grouev, K.; Hering, P.; P.Krejcik,; Lewandowski, J.; Loos, H.; Montagne, T.; Sheppard, J.C.; Stefan, P.; Vlieks, A.; Weathersby, S.; Zhou, F.; /SLAC

    2012-05-16

    LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.

  19. SPS RF System:Tetrodes and Waveguides

    CERN Multimedia

    1977-01-01

    The picture shows part of a RF power generating plant. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

  20. Silicon on insulator MESFETs for RF amplifiers

    Science.gov (United States)

    Wilk, Seth J.; Balijepalli, Asha; Ervin, Joseph; Lepkowski, William; Thornton, Trevor J.

    2010-03-01

    CMOS compatible, high voltage SOI MESFETs have been fabricated using a standard 3.3 V CMOS process without any changes to the process flow. A 0.6 μm gate length device operates with a cut-off frequency of 7.3 GHz and a maximum oscillation frequency of 21 GHz. There is no degradation in device performance up to its breakdown voltage, which greatly exceeds that of CMOS devices on the same process. Other figures-of-merit of relevance to RF front-end design are presented, including the maximum stable gain and noise figure. An accurate representation of the device in SPICE has been developed using the commercially available TOM3 model. Using the SOI MESFET model, a source degenerated low noise RF amplifier targeting operation near 1 GHz has been designed. The amplifier was fabricated on a PCB board and operates at 940 MHz with a minimum NF of 3.8 dB and RF gain of 9.9 dB while only consuming 5mW of DC power.

  1. 33 CFR 159.119 - Operability test; temperature range.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with inlet...

  2. Commissioning of two RF operation modes for RF negative ion source experimental setup at HUST

    Science.gov (United States)

    Li, D.; Chen, D.; Liu, K.; Zhao, P.; Zuo, C.; Wang, X.; Wang, H.; Zhang, L.

    2017-08-01

    An RF-driven negative ion source experimental setup, without a cesium oven and an extraction system, has been built at Huazhong University of Science and Technology (HUST). The working gas is hydrogen, and the typical operational gas pressure is 0.3 Pa. The RF generator is capable of delivering up to 20 kW at 0.9 - 1.1 MHz, and has two operation modes, the fixed-frequency mode and auto-tuning mode. In the fixed-frequency mode, it outputs a steady RF forward power (Pf) at a fixed frequency. In the auto-tuning mode, it adjusts the operating frequency to seek and track the minimum standing wave ratio (SWR) during plasma discharge. To achieve fast frequency tuning, the RF signal source adopts a direct digital synthesizer (DDS). To withstand high SWR during the discharge, a tetrode amplifier is chosen as the final stage amplifier. The trend of maximum power reflection coefficient |ρ|2 at plasma ignition is presented at the fixed frequency of 1.02 MHz with the Pf increasing from 5 kW to 20 kW, which shows the maximum |ρ|2 tends to be "steady" under high RF power. The experiments in auto-tuning mode fail due to over-current protection of screen grid. The possible reason is the relatively large equivalent anode impedance caused by the frequency tuning. The corresponding analysis and possible solution are presented.

  3. Seamless Resource-Adaptive Navigation

    Science.gov (United States)

    Schwartz, Tim; Stahl, Christoph; Baus, Jörg; Wahlster, Wolfgang

    Research in the project RENA (REsource-Adapative NAvigation) together with DFKI GmbH, BMW Research and Technology AG, and Eyeled GmbH has been concerned with the conceptual and methodological foundations and the design of a resource-adaptive platform for seamless outdoor and indoor navigation that can serve as a basis for product development by the companies in the RENA consortium. Future in-car assistance systems will have a user interface, which adapts to the driveŕs current exposure caused by the actual traffic situation.

  4. Deep Sea AUV Navigation Using Multiple Acoustic Beacons

    Institute of Scientific and Technical Information of China (English)

    冀大雄; 宋伟; 赵宏宇; 刘健

    2016-01-01

    Navigation is a critical requirement for the operation of Autonomous Underwater Vehicles (AUVs). To estimate the vehicle position, we present an algorithm using an extended Kalman filter (EKF) to integrate dead-reckoning position with acoustic ranges from multiple beacons pre-deployed in the operating environment. Owing to high latency, variable sound speed multipath transmissions and unreliability in acoustic measurements, outlier recognition techniques are proposed as well. The navigation algorithm has been tested by the recorded data of deep sea AUV during field operations in a variety of environments. Our results show the improved performance over prior techniques based on position computation.

  5. Practical indoor mobile robot navigation using hybrid maps

    DEFF Research Database (Denmark)

    Özkil, Ali Gürcan; Fan, Zhun; Xiao, Jizhong

    2011-01-01

    This paper presents a practical navigation scheme for indoor mobile robots using hybrid maps. The method makes use of metric maps for local navigation and a topological map for global path planning. Metric maps are generated as 2D occupancy grids by a range sensor to represent local information...... about partial areas. The global topological map is used to indicate the connectivity of the 'places-of-interests' in the environment and the interconnectivity of the local maps. Visual tags on the ceiling to be detected by the robot provide valuable information and contribute to reliable localization...... robot and evaluated in a hospital environment....

  6. Autonomous Orbit Determination for Lagrangian Navigation Satellite Based on Neural Network Based State Observer

    Directory of Open Access Journals (Sweden)

    Youtao Gao

    2017-01-01

    Full Text Available In order to improve the accuracy of the dynamical model used in the orbit determination of the Lagrangian navigation satellites, the nonlinear perturbations acting on Lagrangian navigation satellites are estimated by a neural network. A neural network based state observer is applied to autonomously determine the orbits of Lagrangian navigation satellites using only satellite-to-satellite range. This autonomous orbit determination method does not require linearizing the dynamical mode. There is no need to calculate the transition matrix. It is proved that three satellite-to-satellite ranges are needed using this method; therefore, the navigation constellation should include four Lagrangian navigation satellites at least. Four satellites orbiting on the collinear libration orbits are chosen to construct a constellation which is used to demonstrate the utility of this method. Simulation results illustrate that the stable error of autonomous orbit determination is about 10 m. The perturbation can be estimated by the neural network.

  7. Hybrid Ag-based inks for nanocomposite inkjet printed lines: RF properties

    Energy Technology Data Exchange (ETDEWEB)

    Chiolerio, Alessandro [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Camarchia, Vittorio, E-mail: vittorio.camarchia@polito.it [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Electronics and Telecommunications Department, Politecnico di Torino Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Quaglia, Roberto; Pirola, Marco [Electronics and Telecommunications Department, Politecnico di Torino Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Pandolfi, Paolo [Politronica Inkjet Printing S.r.l., C/O i3p, Corso Castelfidardo 30/A, 10129 Torino (Italy); Pirri, Candido Fabrizio [Center for Space Human Robotics, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department, Politecnico di Torino Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2014-12-05

    Highlights: • Polymer–silver nanocomposite conductive ink for RF fast prototyping. • Reduction of the sintering temperature. • Improved printing resolution. • State-of-the-art electrical conductivity. • Good RF performances. - Abstract: The development of highly conductive Ag nanoparticle (NP)-based inkjet printed (IP) connections is a fundamental process for the success of next-generation digitally printed electronics. This is true both at low frequency and at RF, considering the increasing integration of heterogeneous technologies and the use of flexible substrates. Ink-based technologies provide and form at liquid state the functional material that is then delivered to solid via a sintering process to achieve NP coalescence and electrical percolation. Sintering must be performed at very low temperatures (depending on the substrate choice) to be compatible with previous process steps, to preserve the geometry and fulfill the requirements in term of electrical conductivity, as well as to reduce production costs. While IP, as additive technology, is now well settled for DC or low frequency applications, few results on electrical characterization at RF or microwave frequencies are present due to low conductivity, poor geometry definition and low reproducibility. Hence, a good setup of ink formulation and technological realization is fundamental to enable system performance assessment in the high frequency regime. In this paper we propose a breakthrough: we present a nanocomposite ink, whose thermal and DC electrical properties are extremely interesting and competitive with pure-metallic ink systems. Introducing a copolymer in the formulation, we obtained a reduction of the overall sintering temperature, if compared to the pristine NP suspension, along with improved printing resolution together with very good electrical conductivity. The RF characterization has been performed in the range 1–6 GHz on geometries printed on sintered alumina and on a power

  8. Design of the New Wideband RF System for the CERN PS Booster

    CERN Document Server

    Paoluzzi, Mauro; Angoletta, Maria Elena; Arnaudon, Luca; Energico, Salvatore; Findlay, Alan; Haase, Matthias; Jaussi, Michael; Jones, Anthony; Landré, David; Molendijk, John; Quartullo, Danilo; Shaposhnikova, Elena

    2016-01-01

    For the renovation and upgrade of the CERN PS Booster (PSB) RF systems a development project was launched in 2012. The design, based on a new approach, aimed at replacing the existing tuned, narrowband RF systems with wideband, modular, solid-state driven units. A wide range of issues had to be addressed spanning from RF power production, radiation hardness of solid-state devices, active cancellation of beam-induced voltages, dedicated low-level electronics allowing multi-harmonic operation and beam stability. Following a three-year prototyping and testing campaign and two international reviews, the project endorsement came at the end of year 2015. It foresees the complete removal of present h1, h2 and h10 systems and the deployment of a new one covering all the frequency ranges from 1 MHz to 18 MHz. The four PSB rings will be equipped with 144 identical acceleration cells providing 24 kV total RF voltage per ring. This paper describes the design concepts, the retained solutions, the expected performances and...

  9. Persistent and stable biases in spatial learning mechanisms predict navigational style.

    Science.gov (United States)

    Furman, Andrew J; Clements-Stephens, Amy M; Marchette, Steven A; Shelton, Amy L

    2014-12-01

    A wealth of evidence in rodents and humans supports the central roles of two learning systems--hippocampal place learning and striatal response learning--in the formation of spatial representations to support navigation. Individual differences in the ways that these mechanisms are engaged during initial encoding and subsequent navigation may provide a powerful framework for explaining the wide range of variability found in the strategies and solutions that make up human navigational styles. Previous work has revealed that activation in the hippocampal and striatal networks during learning could predict navigational style. Here, we used functional magnetic resonance imaging to investigate the relative activations in these systems during both initial encoding and the act of dynamic navigation in a learned environment. Participants learned a virtual environment and were tested on subsequent navigation to targets within the environment. We observed that a given individual had a consistent balance of memory system engagement across both initial encoding and subsequent navigation, a balance that successfully predicted the participants' tendencies to use novel shortcuts versus familiar paths during dynamic navigation. This was further supported by the observation that the activation during subsequent retrieval was not dependent on the type of solution used on a given trial. Taken together, our results suggest a model in which the place- and response-learning systems are present in parallel to support a variety of navigational behaviors, but stable biases in the engagement of these systems influence what solutions might be available for any given individual.

  10. Radio/FADS/IMU integrated navigation for Mars entry

    Science.gov (United States)

    Jiang, Xiuqiang; Li, Shuang; Huang, Xiangyu

    2018-03-01

    Supposing future orbiting and landing collaborative exploration mission as the potential project background, this paper addresses the issue of Mars entry integrated navigation using radio beacon, flush air data sensing system (FADS), and inertial measurement unit (IMU). The range and Doppler information sensed from an orbiting radio beacon, the dynamic pressure and heating data sensed from flush air data sensing system, and acceleration and attitude angular rate outputs from an inertial measurement unit are integrated in an unscented Kalman filter to perform state estimation and suppress the system and measurement noise. Computer simulations show that the proposed integrated navigation scheme can enhance the navigation accuracy, which enables precise entry guidance for the given Mars orbiting and landing collaborative exploration mission.

  11. Design and manufacture of the RF power supply and RF transmission line for SANAEM project Prometheus

    Science.gov (United States)

    Turemen, G.; Ogur, S.; Ahiska, F.; Yasatekin, B.; Cicek, E.; Ozbey, A.; Kilic, I.; Unel, G.; Alacakir, A.

    2017-08-01

    A 1-5 MeV proton beamline is being built by the Turkish Atomic Energy Authority in collaboration with a number of graduate students from different universities. The primary goal of the project, is to acquire the design ability and manufacturing capability of all the components locally. SPP will be an accelerator and beam diagnostics test facility and it will also serve the detector development community with its low beam current. This paper discusses the design and construction of the RF power supply and the RF transmission line components such as its waveguide converters and its circulator. Additionally low and high power RF test results are presented to compare the performances of the locally produced components to the commercially available ones.

  12. RF design of a C-band compact spherical RF pulse compressor for SXFEL

    Science.gov (United States)

    Li, Zongbin; Fang, Wencheng; Gu, Qiang; Zhao, Zhentang

    2017-08-01

    A new C-band (5712 MHz) compact spherical radio frequency (RF) pulse compressor was designed for the Soft X-ray Free Electron Laser facility (SXFEL) at the Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences (CAS). Using only one high Q0 spherical RF resonant cavity which works on two TE113 modes and a dual-mode polarized coupler, this pulse compressor could achieve an average power gain of 3.8. Associated with the C-band accelerator, an energy gain of 1.85 with the coupling coefficient of 4.9 could be achieved. Particularly it could make the output power stable. This paper presents the scheme of the C-band spherical pulse compressor, as well as the RF design and details of the frequency sensitivities and machining considerations.

  13. Collective strategy for obstacle navigation during cooperative transport by ants.

    Science.gov (United States)

    McCreery, Helen F; Dix, Zachary A; Breed, Michael D; Nagpal, Radhika

    2016-11-01

    Group cohesion and consensus have primarily been studied in the context of discrete decisions, but some group tasks require making serial decisions that build on one another. We examine such collective problem solving by studying obstacle navigation during cooperative transport in ants. In cooperative transport, ants work together to move a large object back to their nest. We blocked cooperative transport groups of Paratrechina longicornis with obstacles of varying complexity, analyzing groups' trajectories to infer what kind of strategy the ants employed. Simple strategies require little information, but more challenging, robust strategies succeed with a wider range of obstacles. We found that transport groups use a stochastic strategy that leads to efficient navigation around simple obstacles, and still succeeds at difficult obstacles. While groups navigating obstacles preferentially move directly toward the nest, they change their behavior over time; the longer the ants are obstructed, the more likely they are to move away from the nest. This increases the chance of finding a path around the obstacle. Groups rapidly changed directions and rarely stalled during navigation, indicating that these ants maintain consensus even when the nest direction is blocked. Although some decisions were aided by the arrival of new ants, at many key points, direction changes were initiated within the group, with no apparent external cause. This ant species is highly effective at navigating complex environments, and implements a flexible strategy that works for both simple and more complex obstacles. © 2016. Published by The Company of Biologists Ltd.

  14. Integrated PET/MR breast cancer imaging: Attenuation correction and implementation of a 16-channel RF coil.

    Science.gov (United States)

    Oehmigen, Mark; Lindemann, Maike E; Lanz, Titus; Kinner, Sonja; Quick, Harald H

    2016-08-01

    This study aims to develop, implement, and evaluate a 16-channel radiofrequency (RF) coil for integrated positron emission tomography/magnetic resonance (PET/MR) imaging of breast cancer. The RF coil is designed for optimized MR imaging performance and PET transparency and attenuation correction (AC) is applied for accurate PET quantification. A 16-channel breast array RF coil was designed for integrated PET/MR hybrid imaging of breast cancer lesions. The RF coil features a lightweight rigid design and is positioned with a spacer at a defined position on the patient table of an integrated PET/MR system. Attenuation correction is performed by generating and applying a dedicated 3D CT-based template attenuation map. Reposition accuracy of the RF coil on the system patient table while using the positioning frame was tested in repeated measurements using MR-visible markers. The MR, PET, and PET/MR imaging performances were systematically evaluated using modular breast phantoms. Attenuation correction of the RF coil was evaluated with difference measurements of the active breast phantoms filled with radiotracer in the PET detector with and without the RF coil in place, serving as a standard of reference measurement. The overall PET/MR imaging performance and PET quantification accuracy of the new 16-channel RF coil and its AC were then evaluated in first clinical examinations on ten patients with local breast cancer. The RF breast array coil provides excellent signal-to-noise ratio and signal homogeneity across the volume of the breast phantoms in MR imaging and visualizes small structures in the phantoms down to 0.4 mm in plane. Difference measurements with PET revealed a global loss and thus attenuation of counts by 13% (mean value across the whole phantom volume) when the RF coil is placed in the PET detector. Local attenuation ranging from 0% in the middle of the phantoms up to 24% was detected in the peripheral regions of the phantoms at positions closer to

  15. Interaction Weaknesses of Personal Navigation Devices

    NARCIS (Netherlands)

    Hipp, Markus; Schaub, Florian; Kargl, Frank; Weber, M.

    2010-01-01

    Automotive navigation systems, especially portable navigation devices (PNDs), are gaining popularity worldwide. Drivers increasingly rely on these devices to guide them to their destination. Some follow them almost blindly, with devastating consequences if the routing goes wrong. Wrong messages as

  16. Navigation in Cross-cultural business relationships

    DEFF Research Database (Denmark)

    Andersen, Poul Houman

    2001-01-01

    Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence......Cross-cultural business navigation concerns the process of handling the complexity of several interacting cultural spheres of influence...

  17. RF System for the MICE Demonstration of Ionisation Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Ronald, K.; et al.

    2017-04-01

    Muon accelerators offer an attractive option for a range of future particle physics experiments. They can enable high energy (TeV+) high energy lepton colliders whilst mitigating the difficulty of synchrotron losses, and can provide intense beams of neutrinos for fundamental physics experiments investigating the physics of flavor. The method of production of muon beams results in high beam emittance which must be reduced for efficient acceleration. Conventional emittance control schemes take too long, given the very short (2.2 microsecond) rest lifetime of the muon. Ionisation cooling offers a much faster approach to reducing particle emittance, and the international MICE collaboration aims to demonstrate this technique for the first time. This paper will present the MICE RF system and its role in the context of the overall experiment.

  18. Electromagnetics of body area networks antennas, propagation, and RF systems

    CERN Document Server

    Werner, Douglas H

    2016-01-01

    The book is a comprehensive treatment of the field, covering fundamental theoretical principles and new technological advancements, state-of-the-art device design, and reviewing examples encompassing a wide range of related sub-areas. In particular, the first area focuses on the recent development of novel wearable and implantable antenna concepts and designs including metamaterial-based wearable antennas, microwave circuit integrated wearable filtering antennas, and textile and/or fabric material enabled wearable antennas. The second set of topics covers advanced wireless propagation and the associated statistical models for on-body, in-body, and off-body modes. Other sub-areas such as efficient numerical human body modeling techniques, artificial phantom synthesis and fabrication, as well as low-power RF integrated circuits and related sensor technology are also discussed. These topics have been carefully selected for their transformational impact on the next generation of body-area network systems and beyo...

  19. CMOS Silicon-on-Sapphire RF Tunable Matching Networks

    Directory of Open Access Journals (Sweden)

    Chamseddine Ahmad

    2006-01-01

    Full Text Available This paper describes the design and optimization of an RF tunable network capable of matching highly mismatched loads to 50 at 1.9 GHz. Tuning was achieved using switched capacitors with low-loss, single-transistor switches. Simulations show that the performance of the matching network depends strongly on the switch performances and on the inductor losses. A 0.5 m silicon-on-sapphire (SOS CMOS technology was chosen for network implementation because of the relatively high-quality monolithic inductors achievable in the process. The matching network provides very good matching for inductive loads, and acceptable matching for highly capacitive loads. A 1 dB compression point greater than dBm was obtained for a wide range of load impedances.

  20. Vision-Aided Inertial Navigation

    Science.gov (United States)

    Roumeliotis, Stergios I. (Inventor); Mourikis, Anastasios I. (Inventor)

    2017-01-01

    This document discloses, among other things, a system and method for implementing an algorithm to determine pose, velocity, acceleration or other navigation information using feature tracking data. The algorithm has computational complexity that is linear with the number of features tracked.

  1. SMALL CRAFT OPERATION AND NAVIGATION.

    Science.gov (United States)

    Louisiana State Dept. of Education, Baton Rouge.

    THIS REFERENCE TEXTBOOK WAS PREPARED FOR USE IN THE FIRST PART OF A TWO-PART COURSE IN MARINE NAVIGATION AND SMALL CRAFT OPERATION ON INLAND AND INTERNATIONAL WATERS. THE MATERIAL WAS DEVELOPED BY AN INDIVIDUAL AUTHOR FOR USE IN TRADE SCHOOL PREPARATORY AND EXTENSION CLASSES FOR MALE ADULTS WHO PLAN TO OPERATE BOATS. IT IS MAINLY CONCERNED WITH…

  2. Safety effects of navigation systems.

    NARCIS (Netherlands)

    2009-01-01

    Increasing numbers of drivers are using navigation systems in their cars. The advantages to the user are obvious: you can get to your destination via the fastest and shortest route. This reduces stress and exposure to other traffic. However, there are also some (unintended) negative effects. For

  3. Celestial navigation in a nutshell

    CERN Document Server

    Schlereth, Hewitt

    2000-01-01

    Celestial Navigation in a Nutshell demonstrates how to take sights by the sun, moon, stars, and planets, discussing the advantages and disadvantages of each method. The reader is taken carefully through several examples and situational illustrations, making this a most effective self-teaching guide. Common errors are reviewed and several tips on how to improve accuracy are given.

  4. Personal Navigation System for Indoor Applications

    OpenAIRE

    Gilliéron, Pierre-Yves; Merminod, Bertrand

    2003-01-01

    Navigation is usually associated with marine and aviation domains. Except for some lighthouses for orientation or landmarks near the coast, navigation instruments are essential because routes are virtual. Therefore, current position of ships and aircrafts must be drawn on the map. Land navigation is generally bound to the road infrastructure. Car navigation systems have been introduced to replace the use of road maps in order to assist the driver in the choise of the correct way...

  5. A Survey of Augmented Reality Navigation

    OpenAIRE

    Bhorkar, Gaurav

    2017-01-01

    Navigation has been a popular area of research in both academia and industry. Combined with maps, and different localization technologies, navigation systems have become robust and more usable. By combining navigation with augmented reality, it can be improved further to become realistic and user friendly. This paper surveys existing researches carried out in this area, describes existing techniques for building augmented reality navigation systems, and the problems faced.

  6. Navigation Issues in the South China Sea

    OpenAIRE

    Niu, Ziru

    2005-01-01

    The South China Sea is one of the most important sea lanes with numerous competing sovereignty disputes. The freedom of navigation in this region is critical to all major trading States in the world. After an introduction to the navigational regimes of UNCLOS, this article describes the whole navigation situation in this region, by separately introducing the navigation issues in the territorial sea, straits, archipelagic waters and the Spratly area. Meanwhile, since the legal status of the ma...

  7. Mobile Robot Navigation Support in Living Environments

    Science.gov (United States)

    Armbrust, Christopher; Koch, Jan; Stocker, Ulf; Berns, Karsten

    Navigation and application functionality of mobile robots rely on their collision-avoiding capabilities, also known as local navigation. We present the mobile robot ARTOS (Autonomous Robot for Transport and Service) that is particularly designed to operate in living environments and therefore faces the problem of fuzzy and unstructured obstacles. The local navigation architecture is motivated regarding decisions on sensor hardware setup as well as the software layers that support and influence navigation control.

  8. RF Sheath-Enhanced Plasma Surface Interaction Studies using Beryllium Optical Emission Spectroscopy in JET ITER-Like Wall

    Energy Technology Data Exchange (ETDEWEB)

    Agarici, G. [Fusion for Energy (F4E), Barcelona, Spain; Klepper, C Christopher [ORNL; Colas, L. [French Atomic Energy Commission (CEA); Krivska, Alena [Ecole Royale Militaire, Brussels Belgium; Bobkov, V. [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, Garching, Germany; Jacquet, P. [Culham Centre for Fusion Energy (CCFE), Abingdon, UK; Delabie, Ephrem G. [ORNL; Giroud, C. [EURATOM / UKAEA, UK; Kirov, K K. [Association EURATOM-CCFE, Abingdon, UK; Lasa Esquisabel, Ane [ORNL; Lerche, E. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Dumortier, P. [ERM-KMS, Association EURATOM-Belgian State, Brussels, Belgium; Durodie, Frederic [Ecole Royale Militaire, Brussels Belgium

    2017-10-01

    A dedicated study on JET-ILW, deploying two types of ICRH antennas and spectroscopic observation spots at two outboard, beryllium limiters, has provided insight on long-range (up to 6m) RFenhanced plasma-surface interactions (RF-PSI) due to near-antenna electric fields. To aid in the interpretation of optical emission measurements of these effects, the antenna near-fields are computed using the TOPICA code, specifically run for the ITER-like antenna (ILA); similar modelling already existed for the standard JET antennas (A2). In the experiment, both antennas were operated in current drive mode, as RF-PSI tends to be higher in this phasing and at similar power (∼0.5 MW). When sweeping the edge magnetic field pitch angle, peaked RF-PSI effects, in the form of 2-4 fold increase in the local Be source,are consistently measured with the observation spots magnetically connect to regions of TOPICAL-calculated high near-fields, particularly at the near-antenna limiters. It is also found that similar RF-PSI effects are produced by the two types of antenna on similarly distant limiters. Although this mapping of calculated near-fields to enhanced RF-PSI gives only qualitative interpretion of the data, the present dataset is expected to provide a sound experimental basis for emerging RF sheath simulation model validation.

  9. RF Sheath-Enhanced Plasma Surface Interaction Studies using Beryllium Optical Emission Spectroscopy in JET ITER-Like Wall

    Directory of Open Access Journals (Sweden)

    Christopher Klepper C.

    2017-01-01

    Full Text Available A dedicated study on JET-ILW, deploying two types of ICRH antennas and spectroscopic observation spots at two outboard, beryllium limiters, has provided insight on long-range (up to 6m RFenhanced plasma-surface interactions (RF-PSI due to near-antenna electric fields. To aid in the interpretation of optical emission measurements of these effects, the antenna near-fields are computed using the TOPICA code, specifically run for the ITER-like antenna (ILA; similar modelling already existed for the standard JET antennas (A2. In the experiment, both antennas were operated in current drive mode, as RF-PSI tends to be higher in this phasing and at similar power (∼0.5 MW. When sweeping the edge magnetic field pitch angle, peaked RF-PSI effects, in the form of 2-4 fold increase in the local Be source,are consistently measured with the observation spots magnetically connect to regions of TOPICAL-calculated high near-fields, particularly at the near-antenna limiters. It is also found that similar RF-PSI effects are produced by the two types of antenna on similarly distant limiters. Although this mapping of calculated near-fields to enhanced RF-PSI gives only qualitative interpretion of the data, the present dataset is expected to provide a sound experimental basis for emerging RF sheath simulation model validation.

  10. RF Sheath-Enhanced Plasma Surface Interaction Studies using Beryllium Optical Emission Spectroscopy in JET ITER-Like Wall

    Science.gov (United States)

    Christopher Klepper, C.; Colas, Laurent; Křivská, Alena; Bobkov, Volodymyr; Jacquet, Philippe; Delabie, Ephrem; Giroud, Carine; Kirov, Krassimir; Lasa, Ane; Lerche, Ernesto; Dumortier, Pierre; Durodié, Frederic; Firdaouss, Mehdi

    2017-10-01

    A dedicated study on JET-ILW, deploying two types of ICRH antennas and spectroscopic observation spots at two outboard, beryllium limiters, has provided insight on long-range (up to 6m) RFenhanced plasma-surface interactions (RF-PSI) due to near-antenna electric fields. To aid in the interpretation of optical emission measurements of these effects, the antenna near-fields are computed using the TOPICA code, specifically run for the ITER-like antenna (ILA); similar modelling already existed for the standard JET antennas (A2). In the experiment, both antennas were operated in current drive mode, as RF-PSI tends to be higher in this phasing and at similar power (˜0.5 MW). When sweeping the edge magnetic field pitch angle, peaked RF-PSI effects, in the form of 2-4 fold increase in the local Be source,are consistently measured with the observation spots magnetically connect to regions of TOPICAL-calculated high near-fields, particularly at the near-antenna limiters. It is also found that similar RF-PSI effects are produced by the two types of antenna on similarly distant limiters. Although this mapping of calculated near-fields to enhanced RF-PSI gives only qualitative interpretion of the data, the present dataset is expected to provide a sound experimental basis for emerging RF sheath simulation model validation.

  11. An Enhanced HL-RF Method for the Computation of Structural Failure Probability Based On Relaxed Approach

    Directory of Open Access Journals (Sweden)

    Behrooz Keshtegar

    2013-06-01

    Full Text Available The computation of structural failure probability is vital importance in the reliability analysis and may be carried out on the basis of the first-order reliability method using various mathematical iterative approaches such as Hasofer-Lind and Rackwitz-Fiessler (HL-RF. This method may not converge in complicated problems and nonlinear limit state functions, which usually shows itself in the form of periodic, bifurcation and chaos solution. In this paper, the HL-RF method has been improved based on the relaxed method to overcome these numerical instabilities. An appropriate relaxed coefficient has been defined, ranging between 0 and 1, to enhance the HL-RF method. This coefficient can be computed using the information from the new and previous iterations of the HL-RF algorithm based on second-order fitting. Capability, robustness and efficiency of the proposed algorithm have been studied by results of several examples compared to the HL-RF. Results illustrated that the proposed method is more efficient and robust in the computation of the failure probability compared to the HL-RF method.

  12. Broadband photonic microwave phase shifter based on controlling two RF modulation sidebands via a Fourier-domain optical processor.

    Science.gov (United States)

    Yang, J; Chan, E H W; Wang, X; Feng, X; Guan, B

    2015-05-04

    An all-optical photonic microwave phase shifter that can realize a continuous 360° phase shift over a wide frequency range is presented. It is based on the new concept of controlling the amplitude and phase of the two RF modulation sidebands via a Fourier-domain optical processor. The operating frequency range of the phase shifter is largely increased compared to the previously reported Fourier-domain optical processor based phase shifter that uses only one RF modulation sideband. This is due to the extension of the lower RF operating frequency by designing the amplitude and phase of one of the RF modulation sidebands while the other sideband is designed to realize the required RF signal phase shift. The two-sideband amplitude-and-phase-control based photonic microwave phase shifter has a simple structure as it only requires a single laser source, a phase modulator, a Fourier-domain optical processor and a single photodetector. Investigation on the bandwidth limitation problem in the conventional Fourier-domain optical processor based phase shifter is presented. Comparisons between the measured phase shifter output RF amplitude and phase responses with theory, which show excellent agreement, are also presented for the first time. Experimental results demonstrate the full -180° to + 180° phase shift with little RF signal amplitude variation of less than 3 dB and with a phase deviation of less than 4° over a 7.5 GHz to 26.5 GHz frequency range, and the phase shifter exhibits a long term stable performance.

  13. “Virtual IED sensor” at an rf-biased electrode in low-pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanova, M. A.; Zyryanov, S. M. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, SINP MSU, Moscow (Russian Federation); Faculty of Physics, Moscow State University, MSU, Moscow (Russian Federation); Lopaev, D. V.; Rakhimov, A. T. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, SINP MSU, Moscow (Russian Federation)

    2016-07-15

    Energy distribution and the flux of the ions coming on a surface are considered as the key-parameters in anisotropic plasma etching. Since direct ion energy distribution (IED) measurements at the treated surface during plasma processing are often hardly possible, there is an opportunity for virtual ones. This work is devoted to the possibility of such indirect IED and ion flux measurements at an rf-biased electrode in low-pressure rf plasma by using a “virtual IED sensor” which represents “in-situ” IED calculations on the absolute scale in accordance with a plasma sheath model containing a set of measurable external parameters. The “virtual IED sensor” should also involve some external calibration procedure. Applicability and accuracy of the “virtual IED sensor” are validated for a dual-frequency reactive ion etching (RIE) inductively coupled plasma (ICP) reactor with a capacitively coupled rf-biased electrode. The validation is carried out for heavy (Ar) and light (H{sub 2}) gases under different discharge conditions (different ICP powers, rf-bias frequencies, and voltages). An EQP mass-spectrometer and an rf-compensated Langmuir probe (LP) are used to characterize plasma, while an rf-compensated retarded field energy analyzer (RFEA) is applied to measure IED and ion flux at the rf-biased electrode. Besides, the pulsed selfbias method is used as an external calibration procedure for ion flux estimating at the rf-biased electrode. It is shown that pulsed selfbias method allows calibrating the IED absolute scale quite accurately. It is also shown that the “virtual IED sensor” based on the simplest collisionless sheath model allows reproducing well enough the experimental IEDs at the pressures when the sheath thickness s is less than the ion mean free path λ{sub i} (s < λ{sub i}). At higher pressure (when s > λ{sub i}), the difference between calculated and experimental IEDs due to ion collisions in the sheath is observed in the low

  14. 46 CFR 129.430 - Navigational lighting.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Navigational lighting. 129.430 Section 129.430 Shipping... INSTALLATIONS Lighting Systems § 129.430 Navigational lighting. (a) Each vessel of less than 100 gross tons and less than 19.8 meters (65 feet) in length must have navigational lighting in compliance with the...

  15. 78 FR 24697 - Inland Waterways Navigation Regulations

    Science.gov (United States)

    2013-04-26

    ... SECURITY Coast Guard 33 CFR Part 162 RIN 1625-AB84 Inland Waterways Navigation Regulations AGENCY: Coast... Navigation (water), Waterways. For the reasons discussed in the preamble, the Coast Guard proposes to amend 33 CFR part 162 as follows: PART 162--INLAND WATERWAYS NAVIGATION REGULATIONS 0 1. The authority...

  16. Global Navigation Satellite System and Augmentation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 22; Issue 12 ... Keywords. Global Navigation Satellite System, GPS, Indian Regional Navigation Satellite System, GLONASS, Galileo, Compass, GAGAN. ... The article also covers the Indian RegionalNavigation Satellite System (IRNSS) and its potentials.

  17. 32 CFR 644.3 - Navigation Projects.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Navigation Projects. 644.3 Section 644.3 National... HANDBOOK Project Planning Civil Works § 644.3 Navigation Projects. (a) Land to be acquired in fee. All... construction and borrow areas. (3) In navigation-only projects, the right to permanently flood should be...

  18. Interactive Thesaurus Navigation: Intelligence Rules OK?

    Science.gov (United States)

    Jones, Susan; And Others

    1995-01-01

    Discusses the feasibility of building intelligent rule- or weight-based algorithms into general-purpose software for interactive thesaurus navigation. Previous research is surveyed; practical investigations in thesaurus navigation and query enhancement are described; and implications for automatic or intelligent thesaurus navigation are…

  19. A study on volunteer augmentation navigation technology

    Science.gov (United States)

    Wu, HaiTao; Lu, XiaoChun; Zou, DeCai; Han, Tao

    2011-06-01

    Navigation augmentation technology is one of the most common methods to increase the continuity, reliability and integrity of the global satellite navigation system. The concept of volunteer augmentation navigation (VNA) is proposed and the elements and topological structure of VNA are also analyzed in this paper. The study focuses on the neural network model that volunteers and ordinary users use modern communication information network to exchange self-organizing information. The neural cell model of Volunteer Augmentation Navigation using shared information is built. Thus interactive general relative positioning is realized. Then basic theories and methods of volunteer augmentation navigation are formed on the basis of the above-mentioned study. This study of realization mechanism of volunteer augmentation technology helps to form a relatively integral architecture of volunteer augmentation navigation. A user self-service satellite navigation augmentation which combines information exchange and navigation services may strengthen the continuity, reliability and integrity of the navigation system. The volunteer augmentation navigation theory proposed in this paper improves the traditional satellite navigation application model and expands the connotation and denotation of satellite navigation augmentation methods.

  20. EM modeling of RF drive in DTL tank 4

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, Sergey S. [Los Alamos National Laboratory

    2012-06-19

    A 3-D MicroWave Studio model for the RF drive in the LANSCE DTL tank 4 has been built. Both eigensolver and time-domain modeling are used to evaluate maximal fields in the drive module and RF coupling. The LANSCE DTL tank 4 has recently been experiencing RF problems, which may or may not be related to its replaced RF coupler. This situation stimulated a request by Dan Rees to provide EM modeling of the RF drive in the DTL tank 4 (T4). Jim O'Hara provided a CAD model that was imported into the CST Microwave Studio (MWS) and after some modifications became a part of a simplified MWS model of the T4 RF drive. This technical note describes the model and presents simulation results.

  1. Effect of the RF sputtering power on microstructural, optical and electrical properties of Al doped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Spadoni, A.; Addonizio, M.L., E-mail: marialuisa.addonizio@enea.it

    2015-08-31

    ZnO:Al (AZO) thin films have been deposited by radio frequency (RF) magnetron sputtering and RF power applied to the target has been varied in the range 600–1200 W. RF power effect on structural, electrical and optical properties was investigated and the relationship existing between these properties and the film lattice defect distribution was discussed. At the increasing of the RF power it was found that AZO films, having a preferential growth orientation along (002) direction, showed a decrease of the lattice distance indicating a less defected structure. Furthermore, at the increase of the RF power a higher optical absorption by free carriers, coupled with an increase of the band gap value, was observed. Resistivity varied from 1.1 × 10{sup −3} Ω cm at 600 W down to a minimum value of 5.6 × 10{sup −4} Ω cm at 1200 W, whereas the carrier density increased up to 1 × 10{sup 21} cm{sup −3}. Lattice defect variation of AZO films was analyzed by photoluminescence (PL) measurements. Presence and amount of different lattice defects were evaluated for AZO films deposited at different RF powers. At 600 W the film structure was dominated by zinc vacancies (V{sub Zn}), whereas for higher RF power the PL band associated with V{sub Zn} decreased and interstitial oxygen (O{sub i}) band remarkably increased. PL analysis revealed that extrinsic Al doping is the dominant effect on the conductivity enhancement. It was hypothesized that at higher RF power a more effective diffusion phenomenon can give more effective Al doping and less amount of zinc vacancies. As a consequence, Al atoms are more effectively trapped into the structure. - Highlights: • ZnO:Al thin films have been deposited by RF sputtering technique. • The effect of the sputtering power on film properties has been investigated. • Electrical, optical and structural characterization has been carried out. • PL analysis revealed lattice defect chemistry variation at the increase of RF power.

  2. PEP-II RF feedback system simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tighe, R. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    A model containing the fundamental impedance of the PEP-II cavity along with the longitudinal beam dynamics and RF feedback system components is in use. It is prepared in a format allowing time-domain as well as frequency-domain analysis and full graphics capability. Matlab and Simulink are control system design and analysis programs (widely available) with many built-in tools. The model allows the use of compiled C-code modules for compute intensive portions. We desire to represent as nearly as possible the components of the feedback system including all delays, sample rates and applicable nonlinearities. (author)

  3. RF microwave circuit design for wireless applications

    CERN Document Server

    Rohde, Ulrich L

    2012-01-01

    Provides researchers and engineers with a complete set of modeling, design, and implementation tools for tackling the newest IC technologies Revised and completely updated, RF/Microwave Circuit Design for Wireless Applications, Second Edition is a unique, state-of-the-art guide to wireless integrated circuit design that provides researchers and engineers with a complete set of modeling, design, and implementation tools for tackling even the newest IC technologies. It emphasizes practical design solutions for high-performance devices and circuitry, incorporating ample exa

  4. STUDIES ON THE RCMS RF SYSTEM.

    Energy Technology Data Exchange (ETDEWEB)

    ZHAO,Y.

    2003-01-22

    This note addresses the various options for the Rapid Cycling Medical Synchrotron (RCMS) RF. The study was divided into three cases, namely non-tuning, tuning and filter. Each case also includes a few options. The primary study was focused on the non-tuning options. However, it was found that it requires too much driver power to cover the wide band and thus causes the cost being too high to be competitive. The proposal of RCMS is not yet clear if it can be approved or not. The results of this study might be useful to other similar machines.

  5. RF and microwave coupled-line circuits

    CERN Document Server

    Mongia, R K; Bhartia, P; Hong, J; Gupta, K C

    2007-01-01

    This extensively revised edition of the 1999 Artech House classic, RF and Microwave Coupled-Line Circuits, offers you a thoroughly up-to-date understanding of coupled line fundamentals, explaining their applications in designing microwave and millimeter-wave components used in today's communications, microwave, and radar systems. The Second Edition includes a wealth of new material, particularly relating to applications. You find brand new discussions on a novel simple design technique for multilayer coupled circuits, high pass filters using coupled lines, software packages used for filter des

  6. RF Transmission Lines on Silicon Substrates

    Science.gov (United States)

    Ponchak, George E.

    1999-01-01

    A review of RF transmission lines on silicon substrates is presented. Through measurements and calculated results, it is shown that attenuation is dominated by conductor loss if silicon substrates with a resistivity greater than 2500 Ohm-cm are used. Si passivation layers affect the transmission line attenuation; however, measured results demonstrate that passivation layers do not necessarily increase attenuation. If standard, low resistivity Si wafers must be used, alternative transmission lines such as thin film microstrip and Co-Planar Waveguide (CPW) on thick polyimide layers must be used. Measured results presented here show that low loss per unit length is achievable with these transmission lines.

  7. Optical fibers and RF a natural combination

    CERN Document Server

    Romeiser, Malcolm

    2004-01-01

    The optical fiber industry has experienced a period of consolidation and reorganization and is now poised for a new surge in growth. To take advantage of that growth, and to respond to the demand to use fiber more efficiently, designers need a better understanding of fiber optics. Taking the approach that optical fibers are an extension of RF-based communications, the author explains basic optical concepts, applications, and systems; the nature and performance characteristics of optical fibers; and optical sources, connectors and splices. Subsequent chapters explore current applications of fib

  8. Integrated 60GHz RF beamforming in CMOS

    CERN Document Server

    Yu, Yikun; van Roermund, Arthur H M

    2011-01-01

    ""Integrated 60GHz RF Beamforming in CMOS"" describes new concepts and design techniques that can be used for 60GHz phased array systems. First, general trends and challenges in low-cost high data-rate 60GHz wireless system are studied, and the phased array technique is introduced to improve the system performance. Second, the system requirements of phase shifters are analyzed, and different phased array architectures are compared. Third, the design and implementation of 60GHz passive and active phase shifters in a CMOS technology are presented. Fourth, the integration of 60GHz phase shifters

  9. Geostar - Navigation location system

    Science.gov (United States)

    Keyser, Donald A.

    The author describes the Radiodetermination Satellite Service (RDSS). The initial phase of the RDSS provides for a unique service enabling central offices and headquarters to obtain position-location information and receive short digital messages from mobile user terminals throughout the contiguous United States, southern Canada, and northern Mexico. The system employs a spread-spectrum, CDMA modulation technique allowing multiple customers to use the system simultaneously, without preassigned coordination with fellow users. Position location is currently determined by employing an existing radio determination receiver, such as Loran-C, GPS, or Transit, in the mobile user terminal. In the early 1990s position location will be determined at a central earth station by time-differential ranging of the user terminals via two or more geostationary satellites. A brief overview of the RDSS system architecture is presented with emphasis on the user terminal and its diverse applications.

  10. Progress on the MICE RF Module at LBNL

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Tianhuan [LBNL, Berkeley; Anderson, Terry [Fermilab; Bross, Alan [Fermilab; DeMello, Allan [LBNL, Berkeley; Lambert, Andrew [LBNL, Berkeley; Li, Derun [LBNL, Berkeley; Loew, Tim [LBNL, Berkeley; Palmer, Mark [Fermilab; Prestemon, Soren [LBNL, Berkeley; Torun, Yagmur [IIT, Chicago (main); Virostek, Steve [LBNL, Berkeley; Wallig, Joseph [LBNL, Berkeley

    2016-06-01

    The international Muon Ionization Cooling Experiment aims to demonstrate the transverse cooling of a muon beam by ionization in energy absorbers. The final MICE cooling channel configuration has two RF modules, each housing a 201 MHz RF cavity used to compensate the longitudinal energy loss in the absorbers. The assembly of MICE RF Module is being carried out at LBL. In this paper we will report the recent progress on the assembly work.

  11. RF power consumption emulation optimized with interval valued homotopies

    DEFF Research Database (Denmark)

    Musiige, Deogratius; Anton, François; Yatskevich, Vital

    2011-01-01

    This paper presents a methodology towards the emulation of the electrical power consumption of the RF device during the cellular phone/handset transmission mode using the LTE technology. The emulation methodology takes the physical environmental variables and the logical interface between...... consumption of the RF device operating at 5MHz using homotopy between 2 continuous power consumptions of the RF device operating at the bandwidths 3MHz and 10MHz....

  12. Studies of RF Breakdown of Metals in Dense Gases

    CERN Document Server

    Hanlet, Pierrick M; Ankenbrandt, Charles; Johnson, Rolland P; Kaplan, Daniel; Kuchnir, Moyses; Moretti, Alfred; Paul, Kevin; Popovic, Milorad; Yarba, Victor; Yonehara, Katsuya

    2005-01-01

    A study of RF breakdown of metals in gases has begun as part of a program to develop RF cavities filled with dense hydrogen gas to be used for muon ionization cooling. A pressurized 800 MHz test cell has been used at Fermilab to compare the conditioning and breakdown behavior of copper, molybdenum, chromium, and beryllium electrodes as functions of hydrogen and helium gas density. These results are compared to the predicted or known RF breakdown behavior of these metals in vacuum.

  13. PEP-II RF System Operation and Performance

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, P.

    2005-01-18

    The Low Energy Ring (LER) and High Energy Ring (HER) RF systems have operated now on PEP-II since July 1998 and have assisted in breaking all design luminosity records back in June 2001. Luminosity on PEP-II has steadily increased since then as a consequence of larger e+ and e- beam currents being accumulated. This has meant that the RF systems have inevitably been driven harder, not only to achieve these higher stored beam currents, but also to reliably keep the beams circulating whilst at the same time minimizing the number of aborts due to RF system faults. This paper details the current PEP-II RF system configurations for both rings, as well as future upgrade plans spanning the next 3-5 years. Limitations of the current RF system configurations are presented, highlighting improvement projects which will target specific areas within the RF systems to ensure that adequate operating overheads are maintained and reliable operation is assured. The Low Energy Ring (LER) and High Energy Ring (HER) RF systems have operated now on PEP-II since July 1998 and have assisted in breaking all design luminosity records back in June 2001. Luminosity on PEP-II has steadily increased since then as a consequence of larger e+ and e- beam currents being accumulated. This has meant that the RF systems have inevitably been driven harder, not only to achieve these higher stored beam currents, but also to reliably keep the beams circulating whilst at the same time minimizing the number of aborts due to RF system faults. This paper details the current PEP-II RF system configurations for both rings, as well as future upgrade plans spanning the next 3-5 years. Limitations of the current RF system configurations are presented, highlighting improvement projects which will target specific areas within the RF systems to ensure that adequate operating overheads are maintained and reliable operation is assured.

  14. 33 CFR 67.35-10 - Private aids to navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Private aids to navigation. 67.35-10 Section 67.35-10 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS... Private aids to navigation. See § 67.15-10(b) for review of applications respecting private aids to...

  15. A review of the ecological effects of radiofrequency electromagnetic fields (RF-EMF).

    Science.gov (United States)

    Cucurachi, S; Tamis, W L M; Vijver, M G; Peijnenburg, W J G M; Bolte, J F B; de Snoo, G R

    2013-01-01

    This article presents a systematic review of published scientific studies on the potential ecological effects of radiofrequency electromagnetic fields (RF-EMF) in the range of 10 MHz to 3.6 GHz (from amplitude modulation, AM, to lower band microwave, MW, EMF). Publications in English were searched in ISI Web of Knowledge and Scholar Google with no restriction on publication date. Five species groups were identified: birds, insects, other vertebrates, other organisms, and plants. Not only clear ecological articles, such as field studies, were taken into consideration, but also biological articles on laboratory studies investigating the effects of RF-EMF with biological endpoints such as fertility, reproduction, behaviour and development, which have a clear ecological significance, were also included. Information was collected from 113 studies from original peer-reviewed publications or from relevant existing reviews. A limited amount of ecological field studies was identified. The majority of the studies were conducted in a laboratory setting on birds (embryos or eggs), small rodents and plants. In 65% of the studies, ecological effects of RF-EMF (50% of the animal studies and about 75% of the plant studies) were found both at high as well as at low dosages. No clear dose-effect relationship could be discerned. Studies finding an effect applied higher durations of exposure and focused more on the GSM frequency ranges. In about two third of the reviewed studies ecological effects of RF-EMF was reported at high as well as at low dosages. The very low dosages are compatible with real field situations, and could be found under environmental conditions. However, a lack of standardisation and a limited number of observations limit the possibility of generalising results from an organism to an ecosystem level. We propose in future studies to conduct more repetitions of observations and explicitly use the available standards for reporting RF-EMF relevant physical parameters

  16. International policy and advisory response regarding children's exposure to radio frequency electromagnetic fields (RF-EMF).

    Science.gov (United States)

    Redmayne, Mary

    2016-01-01

    Radiofrequency electromagnetic field (RF-EMF) exposure regulations/guidelines generally only consider acute effects, and not chronic, low exposures. Concerns for children's exposure are warranted due to the amazingly rapid uptake of many wireless devices by increasingly younger children. This review of policy and advice regarding children's RF-EMF exposure draws material from a wide variety of sources focusing on the current situation. This is not a systematic review, but aims to provide a representative cross-section of policy and advisory responses within set boundaries. There are a wide variety of approaches which I have categorized and tabulated ranging from ICNIRP/IEEE guidelines and "no extra precautions needed" to precautionary or scientific much lower maxima and extensive advice to minimize RF-EMF exposure, ban advertising/sale to children, and add exposure information to packaging. Precautionary standards use what I term an exclusion principle. The wide range of policy approaches can be confusing for parents/carers of children. Some consensus among advisory organizations would be helpful acknowledging that, despite extensive research, the highly complex nature of both RF-EMF and the human body, and frequent technological updates, means simple assurance of long-term safety cannot be guaranteed. Therefore, minimum exposure of children to RF-EMF is recommended. This does not indicate need for alarm, but mirrors routine health-and-safety precautions. Simple steps are suggested. ICNIRP guidelines need to urgently publish how the head, torso, and limbs' exposure limits were calculated and what safety margin was applied since this exposure, especially to the abdomen, is now dominant in many children.

  17. Decay properties of {sup 257}No, {sup 261}Rf, and {sup 262}Rf

    Energy Technology Data Exchange (ETDEWEB)

    Lazarev, Yu. A.; Lobanov, Yu. V.; Oganessian, Yu. Ts.; Utyonkov, V. K.; Abdullin, F. Sh.; Polyakov, A. N.; Rigol, J.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Iliev, S. (and others)

    2000-12-01

    In bombardments of {sup 244}Pu targets with 114- and 120-MeV {sup 22}Ne projectiles we detected 69 {alpha}-{alpha} correlations linking {alpha} decays of {sup 261}Rf and {sup 257}No. We observed one {alpha} peak with E{sub {alpha}}=8.30{+-}0.06 MeV for {sup 261}Rf and peaks with {alpha}-particle energies 8.07--8.40 MeV for {sup 257}No. The half-life of {sup 257}No was measured to be 25{+-}3 s. No correlations were found between {alpha} decays and subsequent spontaneous fission events, from which we calculated an upper limit of 1.5% for the fission branch of {sup 257}No and estimated an upper limit of 3% for the {alpha}-decay branch of {sup 262}Rf. The cross section of the {sup 244}Pu({sup 22}Ne,5n){sup 261}Rf reaction was measured to be about 4 nb at both {sup 22}Ne energies used. We also report on some results from {sup 242}Pu+{sup 22}Ne and {sup 238}U+{sup 26}Mg bombardments.

  18. An inductorless multi-mode RF front end for GNSS receiver in 55 nm CMOS

    Science.gov (United States)

    Yanbin, Luo; Chengyan, Ma; Yebing, Gan; Min, Qian; Tianchun, Ye

    2015-10-01

    An inductorless multi-mode RF front end for a global navigation satellite system (GNSS) receiver is presented. Unlike the traditional topology of a low noise amplifier (LNA), the inductorless current-mode noise-canceling LNA is applied in this design. The high-impedance-input radio frequency amplifier (RFA) further amplifies the GNSS signals and changes the single-end signal path into fully differential. The passive mixer down-converts the signals to the intermediate frequency (IF) band and conveys the signals to the analogue blocks. The local oscillator (LO) buffer divides the output frequency of the voltage controlled oscillator (VCO) and generates 25%-duty-cycle quadrature square waves to drive the mixer. Our measurement results display that the implemented RF front end achieves good overall performance while consuming only 6.7 mA from 1.2 V supply. The input return loss is better than -26 dB and the ultra low noise figure of 1.43 dB leads to high sensitivity of the GNSS receiver. The input 1 dB compression point is -43 dBm at the high gain of 48 dB. The designed circuit is fabricated in 55 nm CMOS technology and the die area, which is much smaller than traditional circuit, is around 220 × 280 μm2.

  19. Projection-based visual guidance for robot-aided RF needle insertion.

    Science.gov (United States)

    Wen, Rong; Chui, Chee-Kong; Ong, Sim-Heng; Lim, Kah-Bin; Chang, Stephen Kin-Yong

    2013-11-01

    The use of projector-based augmented reality (AR) in surgery may enable surgeons to directly view anatomical models and surgical data from the patient's surface (skin). It has the advantages of a consistent viewing focus on the patient, an extended field of view and augmented interaction. This paper presents an AR guidance mechanism with a projector-camera system to provide the surgeon with direct visual feedback for supervision of robotic needle insertion in radiofrequency (RF) ablation treatment. The registration of target organ models to specific positions on the patient body is performed using a surface-matching algorithm and point-based registration. An algorithm based on the extended Kalman filter and spatial transformation is used to intraoperatively compute the virtual needle's depth in the patient's body for AR display. Experiments of this AR system on a mannequin were conducted to evaluate AR visualization and accuracy of virtual RF needle insertion. The average accuracy of 1.86 mm for virtual needle insertion met the clinical requirement of 2 mm or better. The feasibility of augmented interaction with a surgical robot using the proposed open AR interface with active visual feedback was demonstrated. The experimental results demonstrate that this guidance system is effective in assisting a surgeon to perform a robot-assisted radiofrequency ablation procedure. The novelty of the work lies in establishing a navigational procedure for percutaneous surgical augmented intervention integrating a projection-based AR guidance and robotic implementation for surgical needle insertion.

  20. Investigation of Microscopic Materials Limitations of Superconducting RF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Anlage, Steven [Univ. of Maryland, College Park, MD (United States)

    2014-07-23

    The high-field performance of SRF cavities is often limited by breakdown events below the intrinsic limiting surface fields of Nb, and there is abundant evidence that these breakdown events are localized in space inside the cavity. Also, there is a lack of detailed understanding of the causal links between surface treatments and ultimate RF performance at low temperatures. An understanding of these links would provide a clear roadmap for improvement of SRF cavity performance, and establish a cause-and-effect ‘RF materials science’ of Nb. We propose two specific microscopic approaches to addressing these issues. First is a spatially-resolved local microwave-microscope probe that operates at SRF frequencies and temperatures to discover the microscopic origins of breakdown, and produce quantitative measurements of RF critical fields of coatings and films. Second, RF Laser Scanning Microscopy (LSM) has allowed visualization of RF current flow and sources of nonlinear RF response in superconducting devices with micro-meter spatial resolution. The LSM will be used in conjunction with surface preparation and characterization techniques to create definitive links between physical and chemical processing steps and ultimate cryogenic microwave performance. We propose to develop RF laser scanning microscopy of small-sample Nb pieces to establish surface-processing / RF performance relations through measurement of RF current distributions on micron-length scales and low temperatures.

  1. Adaptive RF front-ends for hand-held applications

    CERN Document Server

    van Bezooijen, Andre; van Roermund, Arthur

    2010-01-01

    The RF front-end - antenna combination is a vital part of a mobile phone because its performance is very relevant to the link quality between hand-set and cellular network base-stations. The RF front-end performance suffers from changes in operating environment, like hand-effects, that are often unpredictable. ""Adaptive RF Front-Ends for Hand-Held Applications"" presents an analysis on the impact of fluctuating environmental parameters. In order to overcome undesired behavior two different adaptive control methods are treated that make RF frond-ends more resilient: adaptive impedance control,

  2. Geometry Optimization of DC/RF Photoelectron Gun

    CERN Document Server

    Chen Ping; Yu, David

    2005-01-01

    Pre-acceleration of photoelectrons in a pulsed, high voltage, short, dc gap and its subsequent injection into an rf gun is a promising method to improve electron beam emittance in rf accelerators. Simulation work has been performed in order to optimize the geometric shapes of a dc/rf gun and improve electron beam properties. Variations were made on cathode and anode shapes, dc gap distance, and inlet shape of the rf cavity. Simulations showed that significant improvement on the normalized emittance (< 1 mm-mrad), compared to a dc gun with flat cathode, could be obtained after the geometric shapes of the gun were optimized.

  3. Method of electron emission control in RF guns

    CERN Document Server

    Khodak, I V

    2001-01-01

    The electron emission control method for a RF gun is considered.According to the main idea of the method,the additional resonance system is created in a cathode region where the RF field strength could be varied using the external pulse equipment. The additional resonance system is composed of a coaxial cavity coupled with a RF gun cylindrical cavity via an axial hole. Computed results of radiofrequency and electrodynamic performances of such a two-cavity system and results of the RF gun model pilot study are presented in. Results of particle dynamics simulation are described.

  4. CMOS RF circuit design for reliability and variability

    CERN Document Server

    Yuan, Jiann-Shiun

    2016-01-01

    The subject of this book is CMOS RF circuit design for reliability. The device reliability and process variation issues on RF transmitter and receiver circuits will be particular interest to the readers in the field of semiconductor devices and circuits. This proposed book is unique to explore typical reliability issues in the device and technology level and then to examine their impact on RF wireless transceiver circuit performance. Analytical equations, experimental data, device and circuit simulation results will be given for clear explanation. The main benefit the reader derive from this book will be clear understanding on how device reliability issues affects the RF circuit performance subjected to operation aging and process variations.

  5. Managing Vulnerabilities of Tactical Wireless RF Network Systems: A Case Study

    Directory of Open Access Journals (Sweden)

    Philip Chan

    2011-11-01

    Full Text Available Organisations and individuals benefit when wireless networks are protected. After assessing the risks associated with wireless technologies, organisations can reduce the risks by applying countermeasures to address specific threats and vulnerabilities. These countermeasures include management, operational and technical controls. While these countermeasures will not prevent all penetrations and adverse events, they can be effective in reducing many of the common risks associated with wireless RF networks. Among engineers dealing with different scaled and interconnected engineering systems, such as tactical wireless RF communication systems, there is a growing need for a means of analyzing complex adaptive systems. We propose a methodology based on the systematic resolution of complex issues to manage the vulnerabilities of tactical wireless RF systems. There are is a need to assemble and balance the results of any successful measure, showing how well each solution meets the system’s objectives. The uncertain arguments used and other test results are combined using a form of mathematical theory for their analysis. Systems engineering thinking supports design decisions and enables decision‐makers to manage and assess the support for each solution. In these circumstances, complexity management arises from the many interacting and conflicting requirements of an increasing range of possible parameters. There may not be a single ‘right’ solution, only a satisfactory set of resolutions which this system helps to facilitate. Smart and innovative performance matrixes are introduced using a mathematical Bayesian network to manage, model, calculate and analyse all the potential vulnerability paths in wireless RF networks

  6. Feasibility of measuring thermoregulation during RF heating of the human calf muscle using MR based methods.

    Science.gov (United States)

    Simonis, Frank F J; Petersen, Esben T; Lagendijk, Jan J W; van den Berg, Cornelis A T

    2016-04-01

    One of the main safety concerns in MR is heating of the subject due to radiofrequency (RF) exposure. Recently was shown that local peak temperatures can reach dangerous values and the most prominent parameter for accurate temperature estimations is thermoregulation. Therefore, the goal of this research is testing the feasibility of measuring thermoregulation in vivo using MR methods. The calves of 13 volunteers were scanned at 3 tesla. A Proton Resonance Frequency Shift method was used for temperature measurement. Arterial Spin Labeling and phase contrast scans were used for perfusion and flow measurements respectively. The calves were monitored during extreme RF exposure (20 W/kg, 16 min) and after physical exercise. Temperature increases due to RF absorption (range of the 90th percentile of all volunteers: 1.1-2.5°C) matched with the reference skin temperature changes. Increases in perfusion and flow were defined on the whole leg and normalized to baseline. Perfusion showed a significant increase due to RF heating (ratio compared with baseline: 1.28 ± 0.37; P thermoregulation, which will become essential when new safety guidelines are based on thermal dose. © 2015 Wiley Periodicals, Inc.

  7. Double and triple-harmonic RF buckets and their use for bunch squeezing in AGS

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, C. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-08-24

    For the past several years we have merged bunches in AGS in order to achieve the desired intensity per bunch prior to injection into RHIC. The merging is done on a flat porch at or above AGS injection energy. Because the merges involve the reduction of the RF harmonic number by a factor of 2 (for a 2 to 1 merge) and then a factor of 3 (for a 3 to 1 merge), one requires RF frequencies 6hfs, 3hfs, 2hfs and hfs, where fs is the revolution frequency on the porch and h = 4 is the fundamental harmonic number. The standard AGS RF cavities cannot operate at the lowest frequencies 2hfs and hfs; these are provided by two modified cavities. Upon completion of the merges, the bunches are sitting in harmonic h buckets. In order to be accelerated they need to be squeezed into harmonic 3h buckets. This is accomplished by producing a double-harmonic bucket in which harmonics h and 2h act in concert, and then a triple-harmonic bucket in which harmonics h, 2h, and 3h act in concert. Simulations have shown that the squeeze presents an acceptance bottleneck which limits the longitudinal emittance that can be put into the harmonic 3h bucket. In this note the areas of the double and triple-harmonic buckets are calculated explicitly, and it is shown that these go through a minimum as the RF voltages are raised to the desired values. Several RF voltage ranges are examined, and the acceptance bottleneck is determined for each of these. Finally, the acceptance bottleneck for Au77+ bunches in AGS is calculated for several RF voltage ranges. The main result is that the RF voltages for the low-frequency harmonic h and 2h cavities both must be at least 22 kV in order to achieve an acceptance of 0:6 eV s per nucleon. If the harmonic h and 2h voltages are 15 and 22 kV, respectively, then the acceptance is reduced to 0:548 eV s per nucleon.

  8. Skyrme forces and decay of the Rf266*104 nucleus synthesized via different incoming channels

    Science.gov (United States)

    Niyti, Deep, Aman; Kharab, Rajesh; Chopra, Sahila; Gupta, Raj K.

    2017-03-01

    The excitation functions for the production of 262Rf, 261Rf, and 260Rf isotopes via 4 n -, 5 n -, and 6 n -decay channels from the *266Rf compound nucleus are studied within the dynamical cluster-decay model (DCM), including deformations β2 i and so-called hot-optimum orientations θi which support symmetric fission, in agreement with experiments. The data are available for 18O+248Cm and 22Ne+244Pu reactions, respectively, at the energy ranges of Elab=88.2 to 101.3 and 109.0 to 124.8 MeV. For the nuclear interaction potentials, we use the Skyrme energy density functional (SEDF) based on semiclassical extended Thomas Fermi (ETF) approach, which means an extension of the earlier study of excitation functions of *266Rf formed in 18O+248Cm reaction, based on the DCM using the pocket formula for nuclear proximity potential, showing interaction dependence. The Skyrme forces used here are the old SIII and SIV and new GSkI and KDE0(v1) given for both normal and isospin-rich nuclei, with densities added in frozen density approximation. Interestingly, the DCM gives an excellent fit to the measured data on fusion evaporation residue (ER) for both the incoming channels (18O+248Cm and 22Ne+244Pu ) at the energy range Elab=88.2 to 124.8 MeV, independent of the entrance channel and Skyrme force used. The possible fusion-fission (ff) and quasifission (qf) mass regions of fragments on DCM are also predicted. The DCM with Skyrme forces is further used to look for all the possible target-projectile (t-p) combinations forming the cold compound nucleus (CN) *266Rf at the CN excitation energy of Elab for hot compact configurations. The fusion evaporation residue cross sections, for the proposed new reactions in synthesizing the CN *266Rf, are also estimated for the future experiments, and role of mass asymmetry of nuclei is indicated.

  9. RF tumour ablation: computer simulation and mathematical modelling of the effects of electrical and thermal conductivity.

    Science.gov (United States)

    Lobo, S M; Liu, Z-J; Yu, N C; Humphries, S; Ahmed, M; Cosman, E R; Lenkinski, R E; Goldberg, W; Goldberg, S N

    2005-05-01

    This study determined the effects of thermal conductivity on RF ablation tissue heating using mathematical modelling and computer simulations of RF heating coupled to thermal transport. Computer simulation of the Bio-Heat equation coupled with temperature-dependent solutions for RF electric fields (ETherm) was used to generate temperature profiles 2 cm away from a 3 cm internally-cooled electrode. Multiple conditions of clinically relevant electrical conductivities (0.07-12 S m-1) and 'tumour' radius (5-30 mm) at a given background electrical conductivity (0.12 S m-1) were studied. Temperature response surfaces were plotted for six thermal conductivities, ranging from 0.3-2 W m-1 degrees C (the range of anticipated clinical and experimental systems). A temperature response surface was obtained for each thermal conductivity at 25 electrical conductivities and 17 radii (n=425 temperature data points). The simulated temperature response was fit to a mathematical model derived from prior phantom data. This mathematical model is of the form (T=a+bRc exp(dR) s(f) exp(g)(s)) for RF generator-energy dependent situations and (T=h+k exp(mR)+n?exp(p)(s)) for RF generator-current limited situations, where T is the temperature (degrees C) 2 cm from the electrode and a, b, c, d, f, g, h, k, m, n and p are fitting parameters. For each of the thermal conductivity temperature profiles generated, the mathematical model fit the response surface to an r2 of 0.97-0.99. Parameters a, b, c, d, f, k and m were highly correlated to thermal conductivity (r2=0.96-0.99). The monotonic progression of fitting parameters permitted their mathematical expression using simple functions. Additionally, the effect of thermal conductivity simplified the above equation to the extent that g, h, n and p were found to be invariant. Thus, representation of the temperature response surface could be accurately expressed as a function of electrical conductivity, radius and thermal conductivity. As a result

  10. Navigation in Animals

    Science.gov (United States)

    Matthews, G. V. T.

    This paper was first published in the Journal in 1969 (Vol. 22, p. 118). It is followed by comments from John Kemp.The last twenty-one years have seen some very striking advances in our knowledge of how animals can determine their location. In many cases we have learned that they have available a wider range of stimuli than ourselves for recognizing landmarks and for pilotage within their home area. Thus the associated senses of smell and taste are extraordinarily well developed in some species. The ability of the males of certain moths to detect the scent emitted by females at very considerable distances had long been known. More recently the extreme sensitivity, and selectivity, of fish to waterborne odours has led to an understanding of how they locate their home waters. As but one example, eels have shown reactions to concentrations of chemicals as low as 3 18, equivalent to but two or three molecules within the fish's olfactory sac. In other cases animals have developed sensitivities of which we have little or no conception. Ecolocation is employed by certain birds, by many marine animals and reaches a peak of efficiency in the case of bats. Not only do the latter detect sounds of much higher frequency than ourselves, they also respond to echoes of sounds they emitted but 0·001 seconds earlier. We have little appreciation of the sensations produced by the pressure-receptors in the lateral-line organs of fish.

  11. Integrated navigation of aerial robot for GPS and GPS-denied environment

    Science.gov (United States)

    Suzuki, Satoshi; Min, Hongkyu; Wada, Tetsuya; Nonami, Kenzo

    2016-09-01

    In this study, novel robust navigation system for aerial robot in GPS and GPS- denied environments is proposed. Generally, the aerial robot uses position and velocity information from Global Positioning System (GPS) for guidance and control. However, GPS could not be used in several environments, for example, GPS has huge error near buildings and trees, indoor, and so on. In such GPS-denied environment, Laser Detection and Ranging (LIDER) sensor based navigation system have generally been used. However, LIDER sensor also has an weakness, and it could not be used in the open outdoor environment where GPS could be used. Therefore, it is desired to develop the integrated navigation system which is seamlessly applied to GPS and GPS-denied environments. In this paper, the integrated navigation system for aerial robot using GPS and LIDER is developed. The navigation system is designed based on Extended Kalman Filter, and the effectiveness of the developed system is verified by numerical simulation and experiment.

  12. Methylation of bacterial release factors RF1 and RF2 is required for normal translation termination in vivo.

    Science.gov (United States)

    Mora, Liliana; Heurgué-Hamard, Valérie; de Zamaroczy, Miklos; Kervestin, Stephanie; Buckingham, Richard H

    2007-12-07

    Bacterial release factors RF1 and RF2 are methylated on the Gln residue of a universally conserved tripeptide motif GGQ, which interacts with the peptidyl transferase center of the large ribosomal subunit, triggering hydrolysis of the ester bond in peptidyl-tRNA and releasing the newly synthesized polypeptide from the ribosome. In vitro experiments have shown that the activity of RF2 is stimulated by Gln methylation. The viability of Escherichia coli K12 strains depends on the integrity of the release factor methyltransferase PrmC, because K12 strains are partially deficient in RF2 activity due to the presence of a Thr residue at position 246 instead of Ala. Here, we study in vivo RF1 and RF2 activity at termination codons in competition with programmed frameshifting and the effect of the Ala-246 --> Thr mutation. PrmC inactivation reduces the specific termination activity of RF1 and RF2(Ala-246) by approximately 3- to 4-fold. The mutation Ala-246 --> Thr in RF2 reduces the termination activity in cells approximately 5-fold. After correction for the decrease in level of RF2 due to the autocontrol of RF2 synthesis, the mutation Ala-246 --> Thr reduced RF2 termination activity by approximately 10-fold at UGA codons and UAA codons. PrmC inactivation had no effect on cell growth in rich media but reduced growth considerably on poor carbon sources. This suggests that the expression of some genes needed for optimal growth under such conditions can become growth limiting as a result of inefficient translation termination.

  13. Extremely high frequency RF effects on electronics.

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  14. SPS RF System:Tetrodes and Waveguides

    CERN Multimedia

    1974-01-01

    The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

  15. Pressurized rf cavities in ionizing beams

    Directory of Open Access Journals (Sweden)

    B. Freemire

    2016-06-01

    Full Text Available A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF_{6} and O_{2} were measured.

  16. European global navigation satellite launches

    Science.gov (United States)

    Zielinski, Sarah

    The European Space Agency launched its first Galileo satellite on 28 December 2005.When fully deployed, the Galileo system will provide a European global navigation alternative to the U.S. global positioning system (GPS) and the Russian global navigation satellite system (Glonass).The Galileo system will consist of 30 satellites (27 operational plus three active spare satellites) that are scheduled to be launched and fully operational by the end of 2008.The system will provide real-time positioning within one meter of accuracy and be fully inter-operable with the U.S. and Russian systems. However, unlike GPS and Glonass, Galileo will be under civilian rather than military control.

  17. Navigating the Internet of Things

    DEFF Research Database (Denmark)

    Rassia, Stamatina; Steiner, Henriette

    2017-01-01

    Navigating the Internet of Things is an exploration of interconnected objects, functions, and situations in networks created to ease and manage our daily lives. The Internet of Things represents semi-automated interconnections of different objects in a network based on different information...... technologies. Some examples of this are presented here in order to better understand, explain, and discuss the elements that compose the Internet of Things. In this chapter, we provide a theoretical and practical perspective on both the micro- and macro-scales of ‘things’ (objects), small and large (e.......g. computers or interactive maps), that suggest new topographic relationships and challenge our understanding of users’ involvement with a given technology against the semi-automated workings of these systems. We navigate from a philosophical enquiry into the ‘thingness of things’ dating from the 1950s...

  18. Global Positioning System Navigation Algorithms

    Science.gov (United States)

    1977-05-01

    navigation. Methods for the determination of latitude from direct obser- vations of the sun and stars had been known since Hipparchus, Menelaus , and...is an application of a theorem quoted by Kalman [8:45] that "Given any random process with mean E(x(t)] and covariance E[x(t)x(T)] , there exists a...Wiener-Khintchine theorem which states that the autocorrelation function and the power spectrum form a Fourier transform pair [70:431]. The power

  19. Orientation and navigation in birds

    Directory of Open Access Journals (Sweden)

    H. Bouwman

    1998-07-01

    Full Text Available How birds orientate and navigate over long distances, remains one of the subjects of ornithology eliciting much interest. Birds use combinations of different sources of information to find direction and position. Some of these are the geomagnetic field, celestial bodies, mosaic and gradient maps, sound, smell, idiotetic information and others. Different species use different combinations of sources. This ability is partially inherent and partially learned.

  20. Synthesis of high magnetic moment soft magnetic nanocomposite powders for RF filters and antennas

    Science.gov (United States)

    Chinnasamy, Chins; Malallah, Yaaqoub; Jasinski, Melania M.; Daryoush, Afshin S.

    2015-04-01

    Fe60Co40 alloy nanoparticles with an average particle size of 30 nm were successfully synthesized in gram scale batches using the modified polyol process. The X-ray diffraction and microstructure studies clearly show the formation of the alloy nanoparticles. The saturation magnetization for the gram scale synthesized Fe60Co40 alloy nanoparticles is in the range of 190-205 emu/g at room temperature. The as-synthesized nanoparticles were used to fabricate transmission lines on FR4 substrate to perform radio frequency (RF) characterization of the nanoparticles at ISM RF bands of interest (all in GHz range). The complex permeability extraction of composite Fe60Co40 nanoparticles were performed using perturbation technique applied to microstrip transmission lines by relative measurement of full two port scattering parameter with respect to a baseline FR4 substrate. The extracted results show attractive characteristics for small size antennas and filters.

  1. Modified Navigation Instructions for Spatial Navigation Assistance Systems Lead to Incidental Spatial Learning

    Science.gov (United States)

    Gramann, Klaus; Hoepner, Paul; Karrer-Gauss, Katja

    2017-01-01

    Spatial cognitive skills deteriorate with the increasing use of automated GPS navigation and a general decrease in the ability to orient in space might have further impact on independence, autonomy, and quality of life. In the present study we investigate whether modified navigation instructions support incidental spatial knowledge acquisition. A virtual driving environment was used to examine the impact of modified navigation instructions on spatial learning while using a GPS navigation assistance system. Participants navigated through a simulated urban and suburban environment, using navigation support to reach their destination. Driving performance as well as spatial learning was thereby assessed. Three navigation instruction conditions were tested: (i) a control group that was provided with classical navigation instructions at decision points, and two other groups that received navigation instructions at decision points including either (ii) additional irrelevant information about landmarks or (iii) additional personally relevant information (i.e., individual preferences regarding food, hobbies, etc.), associated with landmarks. Driving performance revealed no differences between navigation instructions. Significant improvements were observed in both modified navigation instruction conditions on three different measures of spatial learning and memory: subsequent navigation of the initial route without navigation assistance, landmark recognition, and sketch map drawing. Future navigation assistance systems could incorporate modified instructions to promote incidental spatial learning and to foster more general spatial cognitive abilities. Such systems might extend mobility across the lifespan. PMID:28243219

  2. Orion Absolute Navigation System Progress and Challenge

    Science.gov (United States)

    Holt, Greg N.; D'Souza, Christopher

    2012-01-01

    The absolute navigation design of NASA's Orion vehicle is described. It has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary onboard measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudo-range and delta-range, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, and cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.

  3. Controlling the dynamics of a self-organized structure using a rf-field

    Energy Technology Data Exchange (ETDEWEB)

    Talasman, S.J.; Ignat, M

    2004-03-15

    We investigate the influence of an external rf-field upon a plasma self-organized structure. We show that depending on the intensity of this field, though it is at very low values, the dynamics of the structure can be easily controlled over a wide range of the state parameters values. This could be considered as a non-feedback method of dynamics control.

  4. Discussion of RF aspects of the proposed project " Remote sensing systems for tunnel-boring machines "

    CERN Document Server

    Caspers, Friedhelm

    1990-01-01

    In a collaboration with the ETH Zurich, EEK department, limits and possibilities of RF remote sensing techniques have been investigated for geological applications. The frequency range of interest here was between 1 MHz and 1 GHz. The use of a vector-networkanalzyer both in reflection- and transmission mode for this type of application is discussed. The present paper is a translation of a report written in German for the ETHZ-EEK in 1989.

  5. Autonomous Navigation by a Mobile Robot

    Science.gov (United States)

    Huntsberger, Terrance; Aghazarian, Hrand

    2005-01-01

    ROAMAN is a computer program for autonomous navigation of a mobile robot on a long (as much as hundreds of meters) traversal of terrain. Developed for use aboard a robotic vehicle (rover) exploring the surface of a remote planet, ROAMAN could also be adapted to similar use on terrestrial mobile robots. ROAMAN implements a combination of algorithms for (1) long-range path planning based on images acquired by mast-mounted, wide-baseline stereoscopic cameras, and (2) local path planning based on images acquired by body-mounted, narrow-baseline stereoscopic cameras. The long-range path-planning algorithm autonomously generates a series of waypoints that are passed to the local path-planning algorithm, which plans obstacle-avoiding legs between the waypoints. Both the long- and short-range algorithms use an occupancy-grid representation in computations to detect obstacles and plan paths. Maps that are maintained by the long- and short-range portions of the software are not shared because substantial localization errors can accumulate during any long traverse. ROAMAN is not guaranteed to generate an optimal shortest path, but does maintain the safety of the rover.

  6. 33 CFR 334.1410 - Pacific Ocean, at Makapuu Point, Waimanalo, Island of Oahu, Hawaii, Makai Undersea Test Range.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Pacific Ocean, at Makapuu Point, Waimanalo, Island of Oahu, Hawaii, Makai Undersea Test Range. 334.1410 Section 334.1410 Navigation and... RESTRICTED AREA REGULATIONS § 334.1410 Pacific Ocean, at Makapuu Point, Waimanalo, Island of Oahu, Hawaii...

  7. RF Reference Switch for Spaceflight Radiometer Calibration

    Science.gov (United States)

    Knuble, Joseph

    2013-01-01

    The goal of this technology is to provide improved calibration and measurement sensitivity to the Soil Moisture Active Passive Mission (SMAP) radiometer. While RF switches have been used in the past to calibrate microwave radiometers, the switch used on SMAP employs several techniques uniquely tailored to the instrument requirements and passive remote-sensing in general to improve radiometer performance. Measurement error and sensitivity are improved by employing techniques to reduce thermal gradients within the device, reduce insertion loss during antenna observations, increase insertion loss temporal stability, and increase rejection of radar and RFI (radio-frequency interference) signals during calibration. The two legs of the single-pole double-throw reference switch employ three PIN diodes per leg in a parallel-shunt configuration to minimize insertion loss and increase stability while exceeding rejection requirements at 1,413 MHz. The high-speed packaged diodes are selected to minimize junction capacitance and resistance while ensuring the parallel devices have very similar I-V curves. Switch rejection is improved by adding high-impedance quarter-wave tapers before and after the diodes, along with replacing the ground via of one diode per leg with an open circuit stub. Errors due to thermal gradients in the switch are reduced by embedding the 50-ohm reference load within the switch, along with using a 0.25-in. (approximately equal to 0.6-cm) aluminum prebacked substrate. Previous spaceflight microwave radiometers did not embed the reference load and thermocouple directly within the calibration switch. In doing so, the SMAP switch reduces error caused by thermal gradients between the load and switch. Thermal issues are further reduced by moving the custom, highspeed regulated driver circuit to a physically separate PWB (printed wiring board). Regarding RF performance, previous spaceflight reference switches have not employed high-impedance tapers to improve

  8. Navigation Operations for the Magnetospheric Multiscale Mission

    Science.gov (United States)

    Long, Anne; Farahmand, Mitra; Carpenter, Russell

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission employs four identical spinning spacecraft flying in highly elliptical Earth orbits. These spacecraft will fly in a series of tetrahedral formations with separations of less than 10 km. MMS navigation operations use onboard navigation to satisfy the mission definitive orbit and time determination requirements and in addition to minimize operations cost and complexity. The onboard navigation subsystem consists of the Navigator GPS receiver with Goddard Enhanced Onboard Navigation System (GEONS) software, and an Ultra-Stable Oscillator. The four MMS spacecraft are operated from a single Mission Operations Center, which includes a Flight Dynamics Operations Area (FDOA) that supports MMS navigation operations, as well as maneuver planning, conjunction assessment and attitude ground operations. The System Manager component of the FDOA automates routine operations processes. The GEONS Ground Support System component of the FDOA provides the tools needed to support MMS navigation operations. This paper provides an overview of the MMS mission and associated navigation requirements and constraints and discusses MMS navigation operations and the associated MMS ground system components built to support navigation-related operations.

  9. RF transconductor linearization robust to process, voltage and temperature variations

    NARCIS (Netherlands)

    Kundur Subramaniyan, H.; Klumperink, Eric A.M.; Srinivasan, Venkatesh; Kiaei, Ali; Nauta, Bram

    2015-01-01

    Software-defined radio receivers increasingly exploit linear RF V-I conversion, instead of RF voltage gain, to improve interference robustness. Unfortunately, the linearity of CMOS inverters, which are often used to implement V-I conversion, is highly sensitive to Process, Voltage and Temperature

  10. Comparative studies of chemically synthesized and RF plasma ...

    Indian Academy of Sciences (India)

    silicon wafer substrates have been prepared by polymerizing o-toluidine monomer under radio frequency (RF) plasma discharge in a home-built set-up. This is a custom manu- factured glass deposition chamber, coupled to a vacuum system and an RF amplifier. For controlled feeding of monomer vapours, a special ...

  11. Characterization of Energy Availability in RF Energy Harvesting Networks

    Directory of Open Access Journals (Sweden)

    Daniela Oliveira

    2016-01-01

    Full Text Available The multiple nodes forming a Radio Frequency (RF Energy Harvesting Network (RF-EHN have the capability of converting received electromagnetic RF signals in energy that can be used to power a network device (the energy harvester. Traditionally the RF signals are provided by high power transmitters (e.g., base stations operating in the neighborhood of the harvesters. Admitting that the transmitters are spatially distributed according to a spatial Poisson process, we start by characterizing the distribution of the RF power received by an energy harvester node. Considering Gamma shadowing and Rayleigh fading, we show that the received RF power can be approximated by the sum of multiple Gamma distributions with different scale and shape parameters. Using the distribution of the received RF power, we derive the probability of a node having enough energy to transmit a packet after a given amount of charging time. The RF power distribution and the probability of a harvester having enough energy to transmit a packet are validated through simulation. The numerical results obtained with the proposed analysis are close to the ones obtained through simulation, which confirms the accuracy of the proposed analysis.

  12. Series-Tuned High Efficiency RF-Power Amplifiers

    DEFF Research Database (Denmark)

    Vidkjær, Jens

    2008-01-01

    An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

  13. Correlates of the MMPI-2-RF in a College Setting

    Science.gov (United States)

    Forbey, Johnathan D.; Lee, Tayla T. C.; Handel, Richard W.

    2010-01-01

    The current study examined empirical correlates of scores on Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF; A. Tellegen & Y. S. Ben-Porath, 2008; Y. S. Ben-Porath & A. Tellegen, 2008) scales in a college setting. The MMPI-2-RF and six criterion measures (assessing anger, assertiveness, sex roles, cognitive…

  14. MMPI-2-RF Characteristics of Custody Evaluation Litigants

    Science.gov (United States)

    Archer, Elizabeth M.; Hagan, Leigh D.; Mason, Janelle; Handel, Richard; Archer, Robert P.

    2012-01-01

    The Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) is a 338-item objective self-report measure drawn from the 567 items of the MMPI-2. Although there is a substantial MMPI-2 literature regarding child custody litigants, there has been only one previously published study using MMPI-2-RF data in this population that…

  15. Predicting Drug Court Treatment Completion Using the MMPI-2-RF

    Science.gov (United States)

    Mattson, Curtis; Powers, Bradley; Halfaker, Dale; Akeson, Steven; Ben-Porath, Yossef

    2012-01-01

    We examined the ability of the Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008) substantive scales to predict Drug Court treatment completion in a sample of individuals identified as being at risk for failure to complete the program. Higher scores on MMPI-2-RF scales…

  16. RF cavity using liquid dielectric for tuning and cooling

    Science.gov (United States)

    Popovic, Milorad [Warrenville, IL; Johnson, Rolland P [Newport News, VA

    2012-04-17

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  17. RF-MEMS capacitive switches with high reliability

    Science.gov (United States)

    Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

    2013-09-03

    A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

  18. LTCC phase shifter modules for RF-MEMS-switch integration

    NARCIS (Netherlands)

    Bartnitzek, T.; Muller, E.; Dijk, R. van

    2005-01-01

    The European 1ST project ARHMS is covering a wide field of R&D activities with the final goal: a satellite based car communication system with a fiat electronically steerable roof antenna based on RF-MEMS. The required phase shift for beam steering will be done with MEMS switches and RF networks. An

  19. Performance Analysis of RF-FSO Multi-Hop Networks

    KAUST Repository

    Makki, Behrooz

    2017-05-12

    We study the performance of multi-hop networks composed of millimeter wave (MMW)-based radio frequency (RF) and free-space optical (FSO) links. The results are obtained in the cases with and without hybrid automatic repeat request (HARQ). Taking the MMW characteristics of the RF links into account, we derive closed-form expressions for the network outage probability. We also evaluate the effect of various parameters such as power amplifiers efficiency, number of antennas as well as different coherence times of the RF and the FSO links on the system performance. Finally, we present mappings between the performance of RF- FSO multi-hop networks and the ones using only the RF- or the FSO-based communication, in the sense that with appropriate parameter settings the same outage probability is achieved in these setups. The results show the efficiency of the RF-FSO setups in different conditions. Moreover, the HARQ can effectively improve the outage probability/energy efficiency, and compensate the effect of hardware impairments in RF-FSO networks. For common parameter settings of the RF-FSO dual- hop networks, outage probability 10^{-4} and code rate 3 nats-per-channel-use, the implementation of HARQ with a maximum of 2 and 3 retransmissions reduces the required power, compared to the cases with no HARQ, by 13 and 17 dB, respectively.

  20. Development of a prototype chest digital tomosynthesis R/F system

    Science.gov (United States)

    Choi, Sunghoon; Lee, Haenghwa; Lee, Donghoon; Choi, Seungyeon; Shin, Jungwook; Jang, Woojin; Seo, Chang-Woo; Kim, Hee-Joung

    2017-03-01

    Digital tomosynthesis has an advantage of low radiation dose compared to conventional computed tomography (CT) by utilizing small number of projections ( 80) acquired over a limited angular range. It can produce 3D volumetric data although they may have some artifacts due to incomplete sampling. Based upon these attractive merits, we developed a prototype digital tomosynthesis R/F system especially for the purpose of applications in chest imaging. Prototype chest digital tomosynthesis (CDT) R/F system contains an X-ray tube with high power R/F pulse generator, flat-panel detector, R/F table, electromechanical radiographic subsystems including precise motor controller, and a reconstruction server. For image reconstruction, users could select the reconstruction option between analytic and iterative methods. Reconstructed images of Catphan700 and LUNGMAN phantoms clearly and rapidly described the internal structures of the phantoms using graphics processing unit (GPU) programming. Contrast-to-noise ratio (CNR) values of the CTP682 module was higher in images using the simultaneous algebraic reconstruction technique (SART) than those using filtered backprojection (FBP) for all materials by factors of 2.60, 3.78, 5.50, 2.30, 3.70, and 2.52 for air, lung foam, low density polyethylene (LDPE), Delrin (acetal homopolymer resin), bone 50% (hydroxyapatite), and Teflon, respectively. Total elapsed times for producing 3D volume were 2.92 sec and 86.29 sec on average for FBP and SART (20 iterations), respectively. The times required for reconstruction were clinically feasible. Moreover, the total radiation dose from the system (5.68 mGy) could demonstrate a significant lowered radiation dose compared to conventional chest CT scan. Consequently, our prototype tomosynthesis R/F system represents an important advance in digital tomosynthesis applications.

  1. A Basic Study on RF Characteristics of Meander Line Employing Periodic Ground Structure on GaAs MMIC for Application to Miniaturization of RF Components

    Directory of Open Access Journals (Sweden)

    Jang-Hyeon Jeong

    2014-01-01

    Full Text Available The meander line employing periodic ground structure (MLEPGS was fabricated on GaAs substrate for application to miniaturization of RF components on MMIC, and its RF characteristics were thoroughly investigated. The MLEPGS with a length of λ/8 showed loss less than 0.72 dB up to 20 GHz, which was low enough for application to RF passive components. The MLEPGS showed much higher propagation constant β and effective permittivity εeff than conventional meander line. Concretely, the MLEPGS with T of 20 μm showed β of 1.08~20.85 rad/mm and εeff of 2703~2479 from 1 to 20 GHz, while the conventional meander line showed β of 0.18~3.36 rad/mm and εeff of 74.2~64.7 in the same frequency range. According to the result, the size of the λ/4 transmission line employing the MLEPGS was 0.151 mm2, which was 3.5% of the size of the transmission line employing conventional meander line.

  2. Smart Glasses for Neurosurgical Navigation by Augmented Reality.

    Science.gov (United States)

    Maruyama, Keisuke; Watanabe, Eiju; Kin, Taichi; Saito, Kuniaki; Kumakiri, Atsushi; Noguchi, Akio; Nagane, Motoo; Shiokawa, Yoshiaki

    2018-01-24

    Wearable devices with heads-up displays or smart glasses can overlay images onto the sight of the wearer. This technology has never been applied to surgical navigation. To assess the applicability and accuracy of smart glasses for augmented reality (AR)-based neurosurgical navigation. Smart glasses were applied to AR-based neurosurgical navigation. Three-dimensional computer graphics were created based on preoperative magnetic resonance images and visualized in see-through smart glasses. Optical markers were attached to the smart glasses and the patient's head for accurate navigation. Two motion capture cameras were used for registration and continuous monitoring of the location of the smart glasses in relation to the patient's head. After the accuracy was assessed with a phantom, this technique was applied in 2 patients with brain tumors located in the brain surface. A stereoscopic view by image overlay through the smart glasses was successful in the phantom and in both patients. Hands-free neuronavigation inside the operative field was available from any angles and distances. The targeting error in the phantom measured in 75 points ranged from 0.2 to 8.1 mm (mean 3.1 ± 1.9 mm, median 2.7 mm). The intraoperative targeting error between the visualized and real locations in the 2 patients (measured in 40 points) ranged from 0.6 to 4.9 mm (mean 2.1 ± 1.1 mm, median 1.8 mm). Smart glasses enabled AR-based neurosurgical navigation in a hands-free fashion. Stereoscopic computer graphics of targeted brain tumors corresponding to the surgical field were clearly visualized during surgery.

  3. RF Breakdown in Normal Conducting Single-cell Structures

    CERN Document Server

    Dolgashev, Valery A; Higo, Toshiyasu; Nantista, Christopher D; Tantawi, Sami G

    2005-01-01

    Operating accelerating gradient in normal conducting accelerating structures is often limited by rf breakdown. The limit depends on multiple parameters, including input rf power, rf circuit, cavity shape and material. Experimental and theoretical study of the effects of these parameters on the breakdown limit in full scale structures is difficult and costly. We use 11.4 GHz single-cell traveling wave and standing wave accelerating structures for experiments and modeling of rf breakdown behavior. These test structures are designed so that the electromagnetic fields in one cell mimic the fields in prototype multicell structures for the X-band linear collider. Fields elsewhere in the test structures are significantly lower than that of the single cell. The setup uses matched mode converters that launch the circular TM01 mode into short test structures. The test structures are connected to the mode launchers with vacuum rf flanges. This setup allows economic testing of different cell geometries, cell materials an...

  4. NQR detection of explosive simulants using RF atomic magnetometers

    Science.gov (United States)

    Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) is a highly selective spectroscopic method that can be used to detect and identify a number of chemicals of interest to the defense, national security, and law enforcement community. In the past, there have been several documented attempts to utilize NQR to detect nitrogen bearing explosives using induction sensors to detect the NQR RF signatures. We present here our work on the NQR detection of explosive simulants using optically pumped RF atomic magnetometers. RF atomic magnetometers can provide an order of magnitude (or more) improvement in sensitivity versus induction sensors and can enable mitigation of RF interference, which has classically has been a problem for conventional NQR using induction sensors. We present the theory of operation of optically pumped RF atomic magnetometers along with the result of laboratory work on the detection of explosive simulant material. An outline of ongoing work will also be presented along with a path for a fieldable detection system.

  5. Wireless Communication Electronics Introduction to RF Circuits and Design Techniques

    CERN Document Server

    Sobot, Robert

    2012-01-01

    This book is intended for senior undergraduate and graduate students as well as practicing engineers who are involved in design and analysis of radio frequency (RF) circuits.  Detailed tutorials are included on all major topics required to understand fundamental principles behind both the main sub-circuits required to design an RF transceiver and the whole communication system. Starting with review of fundamental principles in electromagnetic (EM) transmission and signal propagation, through detailed practical analysis of RF amplifier, mixer, modulator, demodulator, and oscillator circuit topologies, all the way to the system communication theory behind the RF transceiver operation, this book systematically covers all relevant aspects in a way that is suitable for a single semester university level course.   Offers readers a complete, self-sufficient tutorial style textbook; Includes all relevant topics required to study and design an RF receiver in a consistent, coherent way with appropriate depth for a on...

  6. Indoor Wireless RF Energy Transfer for Powering Wireless Sensors

    Directory of Open Access Journals (Sweden)

    H. Visser

    2012-12-01

    Full Text Available For powering wireless sensors in buildings, rechargeable batteries may be used. These batteries will be recharged remotely by dedicated RF sources. Far-field RF energy transport is known to suffer from path loss and therefore the RF power available on the rectifying antenna or rectenna will be very low. As a consequence, the RF-to-DC conversion efficiency of the rectenna will also be very low. By optimizing not only the subsystems of a rectenna but also taking the propagation channel into account and using the channel information for adapting the transmit antenna radiation pattern, the RF energy transport efficiency will be improved. The rectenna optimization, channel modeling and design of a transmit antenna are discussed.

  7. 5 MW 805 MHz SNS RF System Experience

    CERN Document Server

    Young, Karen A; Hardek, Thomas; Lynch, Michael; Rees, Daniel; Roybal, William; Tallerico, Paul J; Thomas Bradley, Joseph

    2005-01-01

    The RF system for the 805 MHz normal conducting linac of the Spallation Nuetron Source (SNS) accelerator was designed, procured and tested at Los Alamos National Laboratory(LANL) and then installed and commissioned at Oak Ridge National Laboratory (ORNL). The RF power for this room temperature coupled cavity linac (CCL) of SNS accelerator is generated by four pulsed 5 MW peak power klystrons operating with a pulse width of 1.25 mSec and a 60 Hz repetition frequency. The RF power from each klystron is divided and delivered to the CCL through two separate RF windows. The 5 MW RF system advanced the state of the art for simultaneous peak and average power. This paper summarizes the problems encountered, lessons learned and results of the high power testing at LANL of the 5 MW klystrons, 5 MW circulators, 5 MW loads, and 2.5 MW windows.*

  8. Alpha- and EC-decay measurements of {sup 257}Rf

    Energy Technology Data Exchange (ETDEWEB)

    Hessberger, F.P. [GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institut Mainz, Mainz (Germany); Antalic, S.; Andel, B.; Kalaninova, Z. [Comenius University in Bratislava, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Mistry, A.K.; Laatiaoui, M. [Helmholtz Institut Mainz, Mainz (Germany); GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Ackermann, D.; Kindler, B.; Kojouharov, I.; Lommel, B. [GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Block, M. [GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institut Mainz, Mainz (Germany); Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Piot, J.; Vostinar, M. [GANIL, Caen (France)

    2016-07-15

    Alpha- and Electron capture (EC) decay properties of {sup 257}Rf were investigated by measuring α-γ coincidences and correlations between conversion electrons (CE) emitted during the process of EC decay of {sup 257}Rf and α decays of the daughter isotope {sup 257}Lr. So far, previously unobserved α (8296 keV)-γ (557 keV) coincidences were measured and interpreted as decays of {sup 257m}Rf (11/2{sup -}[725]) into the 7/2{sup -}[743] level in {sup 253}No. A search of delayed coincidences between α particles and signals at E ≤ 1000 keV, which are interpreted as being due to CE emission, revealed a clear correlation between CE and α particles from the decay of {sup 257}Lr, which is regarded as a direct proof of the EC decay of {sup 257g}Rf and {sup 257m}Rf. (orig.)

  9. Automated Hydroforming of Seamless Superconducting RF Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Tomohiko [ULVAC, Inc.; Shinozawa, Seiichi [ULVAC, Inc.; Abe, Noriyuki [ULVAC, Inc.; Nagakubo, Junki [ULVAC, Inc.; Murakami, Hirohiko [ULVAC, Inc.; Tajima, Tsuyoshi [Los Alamos National Laboratory; Inoue, Hitoshi [High Energy Accelerator Research Organization, KEK; Yamanaka, Masashi [High Energy Accelerator Research Organization, KEK; Ueno, Kenji [High Energy Accelerator Research Organization, KEK

    2012-07-31

    We are studying the possibility of automated hydroforming process for seamless superconducting RF cavities. Preliminary hydroforming tests of three-cell cavities from seamless tubes made of C1020 copper have been performed. The key point of an automated forming is to monitor and strictly control some parameters such as operation time, internal pressure and material displacements. Especially, it is necessary for our studies to be able to control axial and radial deformation independently. We plan to perform the forming in two stages to increase the reliability of successful forming. In the first stage hydroforming by using intermediate constraint dies, three-cell cavities were successfully formed in less than 1 minute. In parallel, we did elongation tests on cavity-quality niobium and confirmed that it is possible to achieve an elongation of >64% in 2 stages that is required for our forming of 1.3 GHz cavities.

  10. RF applications in digital signal processing

    CERN Document Server

    Schilcher, T

    2008-01-01

    Ever higher demands for stability, accuracy, reproducibility, and monitoring capability are being placed on Low-Level Radio Frequency (LLRF) systems of particle accelerators. Meanwhile, continuing rapid advances in digital signal processing technology are being exploited to meet these demands, thus leading to development of digital LLRF systems. The rst part of this course will begin by focusing on some of the important building-blocks of RF signal processing including mixer theory and down-conversion, I/Q (amplitude and phase) detection, digital down-conversion (DDC) and decimation, concluding with a survey of I/Q modulators. The second part of the course will introduce basic concepts of feedback systems, including examples of digital cavity eld and phase control, followed by radial loop architectures. Adaptive feed-forward systems used for the suppression of repetitive beam disturbances will be examined. Finally, applications and principles of system identi cation approaches will be summarized.

  11. RF superconductivity for accelerators. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Padamsee, H. [Cornell Univ., Ithaca, NY (United States). Lab. of Nuclear Studies; Knobloch, J. [BESSY GmbH, Berlin (Germany); Hays, T. [Cosmic Consulting, Gore, VA (United States)

    2008-07-01

    This book introduces some of the key ideas of RF Superconductivity by using a pedagogic approach, and presents a comprehensive overview of the field. It is divided into four parts. The first part introduces the basic concepts of microwave cavities for particle acceleration. The second part is devoted to the observed behavior of superconducting cavities. In the third part, general issues connected with beam-cavity interaction and related issues for critical components are covered. The final part discusses applications of superconducting cavities to frontier accelerators of the future, drawing heavily on examples that are in their most advanced stage. Each part of the book ends in a problems section to illustrate and amplify text material as well as to draw on example applications of superconducting cavities to existing and future accelerators. From the Contents: - Basics - Performance of Superconducting Cavities - Couplers and Tuners - Frontier Accelerators. (orig.)

  12. LHC RF System Time-Domain Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mastorides, T.; Rivetta, C.; /SLAC

    2010-09-14

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  13. A new technique for RF distribution

    Energy Technology Data Exchange (ETDEWEB)

    Madrak, Robyn; Wildman, David

    2014-07-01

    For independent phase and amplitude control, RF cavities are often driven by one power source per cavity. In many cases it would be advantageous in terms of cost to instead use one higher power source for many cavities. Vector modulators have been developed, which, when used with a single source provide for the independent phase and amplitude control which would have been otherwise lost. The key components of these vector modulators are a novel type of phase shifter — adjustable fast phase shifters with perpendicularly biased garnets. The vector modulators have been constructed and used with a single klystron in a 3.4 MeV test linac to successfully accelerate proton beam.

  14. Non-targeted metabolomics analysis of cardiac Muscle Ring Finger-1 (MuRF1), MuRF2, and MuRF3 in vivo reveals novel and redundant metabolic changes.

    Science.gov (United States)

    Banerjee, Ranjan; He, Jun; Spaniel, Carolyn; Quintana, Megan T; Wang, Zhongjing; Bain, James; Newgard, Christopher B; Muehlbauer, Michael J; Willis, Monte S

    2015-04-01

    The muscle-specific ubiquitin ligases MuRF1, MuRF2, MuRF3 have been reported to have overlapping substrate specificities, interacting with each other as well as proteins involved in metabolism and cardiac function. In the heart, all three MuRF family proteins have proven critical to cardiac responses to ischemia and heart failure. The non-targeted metabolomics analysis of MuRF1-/-, MuRF2-/-, and MuRF3-/- hearts was initiated to investigate the hypothesis that MuRF1, MuRF2, and MuRF3 have a similarly altered metabolome, representing alterations in overlapping metabolic processes. Ventricular tissue was flash frozen and quantitatively analyzed by GC/MS using a library built upon the Fiehn GC/MS Metabolomics RTL Library. Non-targeted metabolomic analysis identified significant differences (via VIP statistical analysis) in taurine, myoinositol, and stearic acid for the three MuRF-/- phenotypes relative to their matched controls. Moreover, pathway enrichment analysis demonstrated that MuRF1-/- had significant changes in metabolite(s) involved in taurine metabolism and primary acid biosynthesis while MuRF2-/- had changes associated with ascorbic acid/aldarate metabolism (via VIP and t-test analysis vs. sibling-matched wildtype controls). By identifying the functional metabolic consequences of MuRF1, MuRF2, and MuRF3 in the intact heart, non-targeted metabolomics analysis discovered common pathways functionally affected by cardiac MuRF family proteins in vivo. These novel metabolomics findings will aid in guiding the molecular studies delineating the mechanisms that MuRF family proteins regulate metabolic pathways. Understanding these mechanism is an important key to understanding MuRF family proteins' protective effects on the heart during cardiac disease.

  15. 33 CFR 334.100 - Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Cape May, N.J.; Coast Guard Rifle Range. 334.100 Section 334.100 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.100 Atlantic Ocean off Cape May, N.J.; Coast Guard...

  16. Elevation discrepancies between MMPI-2 clinical and MMPI-2-RF restructured clinical (RC) scales in people with seizure disorders.

    Science.gov (United States)

    Bowden, Stephen C; White, Jessica R; Simpson, Leonie; Ben-Porath, Yossef S

    2014-05-01

    People with seizure disorders experience elevated rates of psychopathology, often undiagnosed and untreated. Accurate diagnosis of psychopathology remains an important goal of quality health care for people with seizure disorders. One of the most widely used dimensional measures of psychopathology is the Minnesota Multiphasic Personality Inventory-Second Edition (MMPI-2). Research in heterogeneous mental health samples suggests that the 2008 revision of this measure, the Minnesota Multiphasic Personality Inventory-Second Edition-Restructured Form (MMPI-2-RF), offers better construct fidelity and more cost-effective administration. This study seeks to extend research on MMPI-2-RF scale elevations to a sample of people with seizure disorders. In a consecutive, heterogeneous sample of people with seizure disorders, MMPI-2 and MMPI-2-RF scores were compared in terms of categorical classification agreement (clinically elevated versus not clinically elevated). Scores were also compared in terms of variance attributable to diagnosis-specific items, general demoralization, subtle items, social desirability, and demographic factors. Scores on MMPI-2 and MMPI-2-RF provided a statistically significant level of agreement between corresponding clinical diagnostic scales ranging from 68% to 84%. Most classification disagreement was attributable to MMPI-2 clinical scale elevations when MMPI-2-RF scales were not elevated. Regression analysis supported the interpretation that general demoralization, subtle items, social desirability, and demographic factors led to MMPI-2 clinical scale elevations. The results provide evidence that in the context of strong psychopathology classification agreement, the MMPI-2-RF restructured clinical scales provide better construct fidelity compared with the more trait heterogeneous MMPI-2 clinical scales. These results should encourage clinicians to use the MMPI-2 Restructured Form (MMPI-2-RF) for improved psychopathology assessment compared with

  17. Study of the dielectric and magnetic properties of Co{sub 2}Y, Y-type hexaferrite (Ba{sub 2}Co{sub 2}Fe{sub 12}O{sub 22}) added with PbO and Bi{sub 2}O{sub 3} in the RF frequency range

    Energy Technology Data Exchange (ETDEWEB)

    Pires, G.F.M.; Rodrigues, H.O. [Departamento de Engenharia de Teleinformatica (DETI), Universidade Federal do Ceara (UFC), CEP 60455-760, Fortaleza, Ceara (Brazil); Laboratorio de Telecomunicacoes e Ciencias e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara (UFC), Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil); Almeida, J.S.; Sancho, E.O.; Goes, J.C. [Laboratorio de Telecomunicacoes e Ciencias e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara (UFC), Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil); Costa, M.M. [Departamento de Fisica, Universidade Federal de Mato Grosso (UFMT), Cuiaba (Brazil); Denardin, J.C. [Universidad de Santiago de Chile, Departamento de Fisica, Avenida Ecuador 3493, Estacion Central, Santiago (Chile); Sombra, A.S.B., E-mail: sombra@ufc.b [Laboratorio de Telecomunicacoes e Ciencias e Engenharia de Materiais (LOCEM), Departamento de Fisica, Universidade Federal do Ceara (UFC), Caixa Postal 6030, CEP 60455-760, Fortaleza, Ceara (Brazil)

    2010-03-18

    In this paper the magnetic and dielectric properties of Y-type hexaferrite (Co{sub 2}Y:Ba{sub 2}Co{sub 2}Fe{sub 12}O{sub 22}) added with 3, 5 and 10 wt.% of PbO and Bi{sub 2}O{sub 3}, obtained in a new procedure of the solid-state method, is presented. The analysis by X-ray diffraction (XRD) using the Rietveld refinement confirmed the formation of single-phase compound with a hexagonal crystal structure (a = b = 5.8560 A and c = 43.4977 A; {alpha} = {beta} = 90{sup o} and {gamma} = 120{sup o}). SEM micrograph of the material shows an uniform distribution of grains throughout the surface of the samples. Detailed studies of the dielectric properties of Co{sub 2}Y, investigated in a wide frequency range (100 Hz to 100 MHz) at room temperature by complex impedance spectroscopy (CIS) technique, showed that these properties are strongly dependent on frequency and on the added level of the impurity. The effect of polyvinyl alcohol (PVA) and tetraethyl orthosilicate (TEOS) on the properties of Co{sub 2}Y hexaferrite was also studied.

  18. GPS Navigation for the Magnetospheric Multi-Scale Mission

    Science.gov (United States)

    Bamford, William; Mitchell, Jason; Southward, Michael; Baldwin, Philip; Winternitz, Luke; Heckler, Gregory; Kurichh, Rishi; Sirotzky, Steve

    2009-01-01

    In 2014. NASA is scheduled to launch the Magnetospheric Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the Earth's magnetosphere. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter

  19. STEPPING - Smartphone-Based Portable Pedestrian Indoor Navigation

    Science.gov (United States)

    Lukianto, C.; Sternberg, H.

    2011-12-01

    Many current smartphones are fitted with GPS receivers, which, in combination with a map application form a pedestrian navigation system for outdoor purposes. However, once an area with insufficient satellite signal coverage is entered, these navigation systems cease to function. For indoor positioning, there are already several solutions available which are usually based on measured distances to reference points. These solutions can achieve resolutions as low as the sub-millimetre range depending on the complexity of the set-up. STEPPING project, developed at HCU Hamburg Germany aims at designing an indoor navigation system consisting of a small inertial navigation system and a new, robust sensor fusion algorithm running on a current smartphone. As this system is theoretically able to integrate any available positioning method, it is independent of a particular method and can thus be realized on a smartphone without affecting user mobility. Potential applications include --but are not limited to: Large trade fairs, airports, parking decks and shopping malls, as well as ambient assisted living scenarios.

  20. Enhanced Mechanisms for Navigation and Tracking Services in Smart Phones

    Directory of Open Access Journals (Sweden)

    L.-C. Chen

    2013-03-01

    Full Text Available Combining Global Positioning System (GPS and Short Message Service (SMS, this paper develops a realisticsystem, called Mobile Navigation and Tracking System (MNTS, to provide navigation and target tracking services.MNTS is an Android based mobile application which integrated many enhanced mechanisms for navigation andtarget tracking services. MNTS not only provides users with the GPS navigation capability, but also supports QuickResponse (QR code decoding, nearby scenic spot searching, friend positioning and target tracking. In targettracking, MNTS utilizing SMS mainly adopts two proposed novel approaches: location prediction and dynamicthreshold to reduce the number of short message transmissions while maintaining location accuracy within anacceptable range. Location prediction utilizes the current target’s location, moving speed, bearing to predict its nextlocation. When the distance between the predicted location and the actual location exceeds a threshold, the targetsends a short message to the tracker to update the actual location. Based on the movement speed of the target,the threshold is dynamically adjusted to balance the location accuracy and the number of short messages.Furthermore, as MNTS is free and open-source software, service providers or developers can easily extend theirown services based on this system.

  1. Enhanced Mechanisms for Navigation and Tracking Services in Smart Phones

    Directory of Open Access Journals (Sweden)

    L.-C. Chen

    2013-04-01

    Full Text Available Combining Global Positioning System (GPS and Short Message Service (SMS, this paper develops a realistic system, called Mobile Navigation and Tracking System (MNTS, to provide navigation and target tracking services. MNTS is an Android based mobile application which integrated many enhanced mechanisms for navigation and target tracking services. MNTS not only provides users with the GPS navigation capability, but also supports Quick Response (QR code decoding, nearby scenic spot searching, friend positioning and target tracking. In target tracking, MNTS utilizing SMS mainly adopts two proposed novel approaches: location prediction and dynamic threshold to reduce the number of short message transmissions while maintaining location accuracy within an acceptable range. Location prediction utilizes the current target’s location, moving speed, bearing to predict its next location. When the distance between the predicted location and the actual location exceeds a threshold, the target sends a short message to the tracker to update the actual location. Based on the movement speed of the target, the threshold is dynamically adjusted to balance the location accuracy and the number of short messages. Furthermore, as MNTS is free and open-source software, service providers or developers can easily extend their own services based on this system.

  2. Learning anticipation via spiking networks: application to navigation control.

    Science.gov (United States)

    Arena, Paolo; Fortuna, Luigi; Frasca, Mattia; Patané, Luca

    2009-02-01

    In this paper, we introduce a network of spiking neurons devoted to navigation control. Three different examples, dealing with stimuli of increasing complexity, are investigated. In the first one, obstacle avoidance in a simulated robot is achieved through a network of spiking neurons. In the second example, a second layer is designed aiming to provide the robot with a target approaching system, making it able to move towards visual targets. Finally, a network of spiking neurons for navigation based on visual cues is introduced. In all cases, the robot was assumed to rely on some a priori known responses to low-level sensors (i.e., to contact sensors in the case of obstacles, to proximity target sensors in the case of visual targets, or to the visual target for navigation with visual cues). Based on their knowledge, the robot has to learn the response to high-level stimuli (i.e., range finder sensors or visual input). The biologically plausible paradigm of spike-timing-dependent plasticity (STDP) is included in the network to make the system able to learn high-level responses that guide navigation through a simple unstructured environment. The learning procedure is based on classical conditioning.

  3. Emerging commercial opportunities based on combined communication navigation services

    Science.gov (United States)

    Gill, Eberhard; Fox, Brian M.; Kreisel, Joerg

    2006-07-01

    Cost reduction pressure on companies and increasing regulatory and legislative demand together with rapid technological progress in space-based communication and navigation are opening up new and exciting commercial opportunities. In this framework, a novel service for maritime applications is presented using a two-way messaging system and the global navigation satellite system (GNSS). The system implements an end-to-end solution for asset tracking and fleet management, positioning and tracing, messaging and security for all types of sea-going vessels. The service applies a vessel-based terminal hosting a GNSS receiver which transmits the navigation status together with messages to a Service Center with a flexible return-link capability. A hybrid space segment is considered comprising the Inmarsat constellation of geostationary communications satellites augmented by two highly inclined low earth orbit satellites for truly global services. Services will be offered to commercial enterprises such as fishing companies as well as public entities such as National Coast Guards. A detailed market analysis has been performed to assess these markets and to determine their penetration. Commercial viability has been proven for business models purely based on Inmarsat and a hybrid space segment using Inmarsat and dedicated micro-satellites. Both cases represent viable businesses in the range of MEUR 100 p.a. Although tailored to a specific market, the approach can be extended to other commercial opportunities requiring space-based communication-navigation services.

  4. 33 CFR 334.540 - Banana River at the Eastern Range, 45th Space Wing, Cape Canaveral Air Force Station, FL...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Banana River at the Eastern Range... AND RESTRICTED AREA REGULATIONS § 334.540 Banana River at the Eastern Range, 45th Space Wing, Cape... navigable waters of the United States, as defined at 33 CFR part 329, within the Banana River contiguous to...

  5. Mobile robot navigation in unknown static environments using ANFIS controller

    Directory of Open Access Journals (Sweden)

    Anish Pandey

    2016-09-01

    Full Text Available Navigation and obstacle avoidance are the most important task for any mobile robots. This article presents the Adaptive Neuro-Fuzzy Inference System (ANFIS controller for mobile robot navigation and obstacle avoidance in the unknown static environments. The different sensors such as ultrasonic range finder sensor and sharp infrared range sensor are used to detect the forward obstacles in the environments. The inputs of the ANFIS controller are obstacle distances obtained from the sensors, and the controller output is a robot steering angle. The primary objective of the present work is to use ANFIS controller to guide the mobile robot in the given environments. Computer simulations are conducted through MATLAB software and implemented in real time by using C/C++ language running Arduino microcontroller based mobile robot. Moreover, the successful experimental results on the actual mobile robot demonstrate the effectiveness and efficiency of the proposed controller.

  6. Compact Power Conditioning and RF Systems for a High Power RF Source

    Science.gov (United States)

    2008-12-01

    inductors LS1, LS2, and LS3 are saturating magnetic cores that sequentially switch the parallel inductors into the circuit . The MU simulator is...the high voltage stages of load operation. The capacitor charged to -190 kV before the oil spark gap closed to form an underdamped RLC circuit with...fuse. The RF source consists of a high voltage, low inductance capacitor and a low inductance closing switch and shunt. An antenna in parallel with

  7. INS/CNS/GNSS integrated navigation technology

    CERN Document Server

    Quan, Wei; Gong, Xiaolin; Fang, Jiancheng

    2015-01-01

    This book not only introduces the principles of INS, CNS and GNSS, the related filters and semi-physical simulation, but also systematically discusses the key technologies needed for integrated navigations of INS/GNSS, INS/CNS, and INS/CNS/GNSS, respectively. INS/CNS/GNSS integrated navigation technology has established itself as an effective tool for precise positioning navigation, which can make full use of the complementary characteristics of different navigation sub-systems and greatly improve the accuracy and reliability of the integrated navigation system. The book offers a valuable reference guide for graduate students, engineers and researchers in the fields of navigation and its control. Dr. Wei Quan, Dr. Jianli Li, Dr. Xiaolin Gong and Dr. Jiancheng Fang are all researchers at the Beijing University of Aeronautics and Astronautics.

  8. Steady state RF facility for testing ITER ICRH RF contact component

    Energy Technology Data Exchange (ETDEWEB)

    Argouarch, A., E-mail: arnaud.argouarch@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Bamber, R. [Euratom/CCFE Association, Culham Science Centre, Abingdon, Oxon, OX143DB (United Kingdom); Bernard, J.M.; Delaplanche, J.M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Durodié, F. [Laboratory for Plasmas Physics, 1000 Brussels (Belgium); Larroque, S.; Lecomte, P.; Lombard, G.; Hatchressian, J.C.; Mollard, P.; Mouyon, D.; Pagano, M.; Patterlini, J.C.; Rasio, S.; Soler, B.; Toulouse, L.; Thouvenin, D.; Verger, J.M.; Vigne, T.; Volpe, R. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2013-10-15

    After the installation and commissioning of the TITAN [1,2], test facility, a key element – the T resonator – was assembled in order to facilitate testing components at high RF voltages and currents. This work is within the CEA roadmap for testing ITER ICRH components in a relevant environment. Several components of the future ITER ICRH antenna have been targeted. The embedded RF contact within the ITER ICRH antenna appeared as a critical component for antenna performance, requiring extensive R and D. Therefore, CEA has proposed and subsequently prepared a platform to test and validate the anticipated RF contact. A steady state resonator with active water cooling has been manufactured and assembled within the TITAN facility, including a hot pressurized water loop. The program consists of testing the contact at 2.25 kA and 62 MHz in steady state conditions. Sliding tests are also performed at high temperature and vacuum to understand component aging, including wear. The equipment installed is consistent with that required to test an ITER ICRH extensively.

  9. On the performance of hybrid RF and RF/FSO dual-hop transmission systems

    KAUST Repository

    Ansari, Imran Shafique

    2013-10-01

    In this work, we present the performance analysis of a dual-branch transmission system composed of a direct radio frequency (RF) link and a dual-hop relay composed of asymmetric RF and free-space optical (FSO) links. The FSO link accounts for pointing errors and both types of detection techniques (i.e. intensity modulation/direct detection (IM/DD) as well as heterodyne detection). The performance is evaluated under the assumption of selection combining (SC) diversity scheme. RF links are modeled by Rayleigh fading distribution whereas the FSO link is modeled by a unified Gamma-Gamma fading distribution. Specifically, we derive new exact closed-form expressions for the cumulative distribution function, probability density function, moment generating function, and moments of the end-to-end signal-to-noise ratio of such systems in terms of the Meijer\\'s G function. We then capitalize on these results to offer new exact closed-form expressions for the outage probability, higher-order amount of fading, average error rate for binary and M-ary modulation schemes, and ergodic capacity, all in terms of Meijer\\'s G functions. © 2013 IEEE.

  10. Automatic Pole and Q-Value Extraction for RF Structures

    Energy Technology Data Exchange (ETDEWEB)

    C. Potratz, H.-W. Glock, U. van Rienen, F. Marhauser

    2011-09-01

    The experimental characterization of RF structures like accelerating cavities often demands for measuring resonant frequencies of Eigenmodes and corresponding (loaded) Q-values over a wide spectral range. A common procedure to determine the Q-values is the -3dB method, which works well for isolated poles, but may not be applicable directly in case of multiple poles residing in close proximity (e.g. for adjacent transverse modes differing by polarization). Although alternative methods may be used in such cases, this often comes at the expense of inherent systematic errors. We have developed an automation algorithm, which not only speeds up the measurement time significantly, but is also able to extract Eigenfrequencies and Q-values both for well isolated and overlapping poles. At the same time the measurement accuracy may be improved as a major benefit. To utilize this procedure merely complex scattering parameters have to be recorded for the spectral range of interest. In this paper we present the proposed algorithm applied to experimental data recorded for superconducting higher-order-mode damped multi-cell cavities as an application of high importance.

  11. Prospects for integration of satellite communications, navigation and monitoring functions

    Science.gov (United States)

    Kinal, George

    1989-03-01

    The basic equations of analog ranging are shown to be essentially identical to those for digital time synchronization. Digital system design parameters such as energy per bit, bandwidth and data rate indicate that communications and ranging/timing are two sides of the same coin. Integrated user equipment such as navigation receivers and standard C terminals are shown to be less expensive and more convenient to operate than separate systems. Extensive sharing of hardware functions is possible. The distinction between communications and ranging can be considered to be a software matter. The role of Inmarsat in furthering such integration is described.

  12. Sources of Error in Satellite Navigation Positioning

    Directory of Open Access Journals (Sweden)

    Jacek Januszewski

    2017-09-01

    Full Text Available An uninterrupted information about the user’s position can be obtained generally from satellite navigation system (SNS. At the time of this writing (January 2017 currently two global SNSs, GPS and GLONASS, are fully operational, two next, also global, Galileo and BeiDou are under construction. In each SNS the accuracy of the user’s position is affected by the three main factors: accuracy of each satellite position, accuracy of pseudorange measurement and satellite geometry. The user’s position error is a function of both the pseudorange error called UERE (User Equivalent Range Error and user/satellite geometry expressed by right Dilution Of Precision (DOP coefficient. This error is decomposed into two types of errors: the signal in space ranging error called URE (User Range Error and the user equipment error UEE. The detailed analyses of URE, UEE, UERE and DOP coefficients, and the changes of DOP coefficients in different days are presented in this paper.

  13. Estimating the Odometry Error of a Mobile Robot during Navigation

    OpenAIRE

    Martinelli, Agostino; Siegwart, Roland

    2003-01-01

    This paper addresses the problem of the odometry error estimation during the robot navigation. The robot is equipped with an external sensor (like laser range finder). Concerning the systematic error an augmented Kalman Filter is introduced. This filter estimates a vector state containing the robot configuration and the parameters characterizing the systematic component of the odometry error. It uses encoder readings as inputs and the readings from the external sensor as observations. The est...

  14. Comparability of scores on the MMPI-2-RF scales generated with the MMPI-2 and MMPI-2-RF booklets.

    Science.gov (United States)

    Van der Heijden, P T; Egger, J I M; Derksen, J J L

    2010-05-01

    In most validity studies on the recently released 338-item MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008; Tellegen & Ben-Porath, 2008), scale scores were derived from the 567-item MMPI-2 booklet. In this study, we evaluated the comparability of the MMPI-2-RF scale scores derived from the original 567-item MMPI-2 booklet with MMPI-2-RF scale scores derived from the 338-item MMPI-2-RF booklet in a Dutch student sample (N = 107). We used a counterbalanced (ABBA) design. We compared results with those previously reported by Tellegen and Ben-Porath (2008). Our findings support the comparability of the scores of the 338-item version and the 567-item version of the 50 MMPI-2-RF scales. We discuss clinical implications and directions for further research.

  15. Global navigation satellite systems and their applications

    CERN Document Server

    Madry, Scott

    2015-01-01

    Dr. Madry, one of the world's leading experts in the field, provides in a condensed form a quick yet comprehensive overview of satellite navigation. This book concisely addresses the latest technology, the applications, the regulatory issues, and the strategic implications of satellite navigation systems. This assesses the strengths and weaknesses of satellite navigation networks and review of all the various national systems now being deployed and the motivation behind the proliferation of these systems.

  16. Emergency Navigation without an Infrastructure

    Directory of Open Access Journals (Sweden)

    Erol Gelenbe

    2014-08-01

    Full Text Available Emergency navigation systems for buildings and other built environments, such as sport arenas or shopping centres, typically rely on simple sensor networks to detect emergencies and, then, provide automatic signs to direct the evacuees. The major drawbacks of such static wireless sensor network (WSN-based emergency navigation systems are the very limited computing capacity, which makes adaptivity very difficult, and the restricted battery power, due to the low cost of sensor nodes for unattended operation. If static wireless sensor networks and cloud-computing can be integrated, then intensive computations that are needed to determine optimal evacuation routes in the presence of time-varying hazards can be offloaded to the cloud, but the disadvantages of limited battery life-time at the client side, as well as the high likelihood of system malfunction during an emergency still remain. By making use of the powerful sensing ability of smart phones, which are increasingly ubiquitous, this paper presents a cloud-enabled indoor emergency navigation framework to direct evacuees in a coordinated fashion and to improve the reliability and resilience for both communication and localization. By combining social potential fields (SPF and a cognitive packet network (CPN-based algorithm, evacuees are guided to exits in dynamic loose clusters. Rather than relying on a conventional telecommunications infrastructure, we suggest an ad hoc cognitive packet network (AHCPN-based protocol to adaptively search optimal communication routes between portable devices and the network egress nodes that provide access to cloud servers, in a manner that spares the remaining battery power of smart phones and minimizes the time latency. Experimental results through detailed simulations indicate that smart human motion and smart network management can increase the survival rate of evacuees and reduce the number of drained smart phones in an evacuation process.

  17. Emergency navigation without an infrastructure.

    Science.gov (United States)

    Gelenbe, Erol; Bi, Huibo

    2014-08-18

    Emergency navigation systems for buildings and other built environments, such as sport arenas or shopping centres, typically rely on simple sensor networks to detect emergencies and, then, provide automatic signs to direct the evacuees. The major drawbacks of such static wireless sensor network (WSN)-based emergency navigation systems are the very limited computing capacity, which makes adaptivity very difficult, and the restricted battery power, due to the low cost of sensor nodes for unattended operation. If static wireless sensor networks and cloud-computing can be integrated, then intensive computations that are needed to determine optimal evacuation routes in the presence of time-varying hazards can be offloaded to the cloud, but the disadvantages of limited battery life-time at the client side, as well as the high likelihood of system malfunction during an emergency still remain. By making use of the powerful sensing ability of smart phones, which are increasingly ubiquitous, this paper presents a cloud-enabled indoor emergency navigation framework to direct evacuees in a coordinated fashion and to improve the reliability and resilience for both communication and localization. By combining social potential fields (SPF) and a cognitive packet network (CPN)-based algorithm, evacuees are guided to exits in dynamic loose clusters. Rather than relying on a conventional telecommunications infrastructure, we suggest an ad hoc cognitive packet network (AHCPN)-based protocol to adaptively search optimal communication routes between portable devices and the network egress nodes that provide access to cloud servers, in a manner that spares the remaining battery power of smart phones and minimizes the time latency. Experimental results through detailed simulations indicate that smart human motion and smart network management can increase the survival rate of evacuees and reduce the number of drained smart phones in an evacuation process.

  18. Use of the Far Infrared Tangential Interferometer/Polarimeter diagnostic for the study of rf driven plasma waves on NSTX.

    Science.gov (United States)

    Kim, J; Lee, K C; Kaita, R; Phillips, C K; Domier, C W; Valeo, E; Luhmann, N C; Bonoli, P T; Park, H

    2010-10-01

    A rf detection system for waves in the 30 MHz range has been constructed for the Far Infrared Tangential Interferometer/Polarimeter on National Spherical Torus Experiment (NSTX). It is aimed at monitoring high frequency density fluctuations driven by 30 MHz high harmonic fast wave fields. The levels of density fluctuations at various radial chords and antenna phase angles can be estimated using the electric field calculated by TORIC code and linearized continuity equation for the electron density. In this paper, the experimental arrangement for the detection of rf signal and preliminary results of simulation will be discussed.

  19. Measurement method of time jitter between pump laser pulse and RF wave by the charge change in photo-injector

    CERN Document Server

    Liu Sheng Guang; Wang Ming Kai

    2002-01-01

    In photo-cathode RF gun, the Schottky effect in process of photoemission and electron longitudinal accelerating process bring forth a linear work range in which electron charge out of gun is linear proportion to laser injection phase. According to the result, the authors develop a method that can be used to measure time jitter between laser pulse and RF wave. The method can attain to high precision and small error. On general photo-injector condition, the precision is almost 1.15 fs, the error is almost 0.23 fs

  20. Low Power Universal Direct Conversion Transmit and Receive (UTR) RF Module for Software Defined Radios Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Conventional software defined radio (SDR) backend signal processors are limited by apriori system definitions and respectively chosen RF hardware. Ideally, the RF...