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Conference on Aerial Surveillance Sensing Including Obscured and Underground Object Detection

作者： BLAZEJEWSKI, ER WILLIAMS, GM MCLEVIGE, WV VANDERWYCK, AB EDWALL, DD GERTNER, ER ELLSWORTH, J FISHMAN, L HAMPTON, S VYDYANATH, H ROCKWELL INT CORP CTR SCITHOUSAND OAKSCA 91360

ISBN: (纸本)0819415219

`The demand for high detectivity LWIR IR focal plane arrays that operate at low backgrounds is shown to drive the HgCdTe technology toward increased detector performance. Reduced operating temperature together with advanced material technology and detector design are presented as solutions. High performance MWIR, MLWIR and LWIR HgCdTe detector test arrays and variable area test structures were recently demonstrated through the joint collaboration of Aerojet Electronic systems Division and Rockwell International. These devices are based on the innovative buried planar heterostructure (BPH) detector architecture grown by liquid phase epitaxy of HgCdTe on ii-VI substrates. The major features of the BPH design include planar geometry, heterostructure wide gap p-type on narrow gap n-type HgCdTe and a buried LWIR electrical junction. Excellent 78K median R_(omicron )A performance across the IR spectrum from 5.2 micrometers to 12 micrometers is reported and shown to follow the diffusion trend line. Excellent 40K median R_(omicron )A performance for devices with cutoffs ranging from 9 micrometers to 19 micrometers are also presented. LWIR R_(omicron )A statistical performance data at both 78K and 40K from fanout test arrays are presented with median R_(omicron )A values of 100 ohm-cm² at 78K and > 10⁶ ohm-cm² at 40K for cutoffs of 10.4 micrometers and 11.4 micrometers respectively. The 90% test array operability was found to exceed 5 x 10⁵ ohm-cm² at 40K. Devices with median R_(omicron )As of 20 ohm-cm² at 78K and 7 x 10⁵ ohm-cm² at 40K were measured for cutoffs of 12 micrometers and 13 micrometers respectively. Uniform and high quantum efficiencies were measured at 40K with a median of approximately equals 70%.

关键词： sensors Mercury cadmium telluride Long wavelength infrared Diffusion Diodes Mid-IR Quantum efficiency Heterojunctions sensor performance Detector arrays

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THE CHIMERA-ii REAL-TIME OPERATING SYSTEM FOR advanced sensor-BASED CONTROL applications

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IEEE TRANSACTIONS ON systems MAN AND CYBERNETICS 1992年第6期22卷 1282-1295页

作者： STEWART, DB SCHMITZ, DE KHOSLA, PK TRANSARC CORP PITTSBURGHPA 15219

The Chimera ii Real-Time Operating System, which has been developed for advanced sensor-based control applications. It has been designed as a local operating system, to be used in conjunction with a global operating system, is described. It executes on one or more single board computers in a VMEbus-based system. advanced sensor-based control systems are both statically and dynamically reconfigurable. As a result, they require many special features, which are currently not found in commercial real-time operating systems. Several design issues for such systems are presented as well as the features we have developed and implemented as part of Chimera ii. These features include a real-time kernel with dynamic scheduling, global error handling, user signals, and two levels of device drivers;an enhanced collection of interprocessor communication mechanisms, including global shared memory, spin-locks, remote semaphores, priority message passing, global state variable tables, multiprocessor servo task control, and host workstation integration;and several support utilities, including UNIX C and math libraries, a matrix library, a command interpreter library, and a configuration file library. Chimera ii is currently being used with a variety of systems, including the CMU Direct Drive Arm ii, the CMU Reconfigurable Modular Manipulator System, the Troikabot System for Rapid Assembly, and the Self-Mobile Space Manipulator.

关键词： Real time systems Operating systems Libraries Control systems Signal design Kernel Dynamic scheduling Error correction Message passing Servomechanisms

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A VERSATILE ELECTROOPTICAL sensor PROVIDES FEEDBACK FOR CONTROLS-STRUCTURES INTERACTION 2

A VERSATILE ELECTROOPTICAL SENSOR PROVIDES FEEDBACK FOR CONT...

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CONF ON SURVEILLANCE TECHNOLOGIES 2

作者： COFFELT, E SCHROEDER, C Ball Aerospace Systems Group Electro-Optics/Cryogenics Division

ISBN: (纸本)0819408581

The importance of remote sensing for high-rate, high-accuracy position feedback in the control of large flexible structures is gaining wide recognition. Less obvious is the equally important use of these sensors for target tracking, proximity sensing, systems identification, and other control-related applications. The remote attitude measurement sensor (RAMS) can be easily adapted to satisfy each of these applications by selecting the optical components to meet specific measurement needs. The RAMS system has been configured to accept many different lens/target combinations and thereby provide versatility, ease of use, and reliable performance. Examples of typical applications are provided, along with descriptions of the sensor configurations and performance. Recent experiences in RAMS hardware development and testing are also described, including the use of RAMS for the Control, Astrophysics, and Structures Experiment in Space (CASES) advanced Development Facility (ADF) and the controls-structures interaction demonstration experiment (C-SIDE). © 1992 SPIE. All rights reserved.

关键词： Astrophysics

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NOVEL POSITION sensor TECHNOLOGIES FOR MICROACCELEROMETERS 2

NOVEL POSITION SENSOR TECHNOLOGIES FOR MICROACCELEROMETERS

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CONF ON sensorS AND sensor systems FOR GUIDANCE AND NAVIGATION 2

作者： VANZANDT, TR KENNY, TW KAISER, WJ Jet Propulsion Lab. (United States)

ISBN: (纸本)081940859X

An important new approach for vehicle guidance and control is based on the use of compact, low-mass, low-cost sensors integrated with the vehicle structure. Many advantages of this approach lead to new capabilities. However, the development of compact guidance and control sensors leads to a variety of fundamental physical problems associated with sensor sensitivity and noise. For example, as sensor size is reduced, it becomes necessary to improve the sensitivity of the sensor signal detection mechanism. These challenges to sensor development will be described. Recent developments at JPL, based on new position sensor principles such as electron tunneling, have produced a series of novel, ultra-high sensitivity micro-sensors and micro-instruments. Included among the applications demonstrated, are a high sensitivity micro-accelerometer and micro-seismometer. In this paper, the fundamental limits of conventional position sensors will be discussed and a new position sensor for advanced accelerometers will be described.

关键词： sensors Electrodes Position sensors Field emission displays Capacitors Actuators Signal detection Transducers sensor technology Silicon

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sensors and sensor systems for Guidance and Navigation ii

Sensors and Sensor Systems for Guidance and Navigation II

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sensors and sensor systems for Guidance and Navigation ii 1992

The proceedings contain 32 papers. The topic discussed include: application of new GPS aircraft control/display system to topographic mapping of the Greenland ice cap;application of advanced guidance and navigation systems to flight control of aircraft and future space vehicles;microgravity monitoring instrument development and application to vernier guidance, navigation, and vehicle control;microfabricated magnetometer using young's modulus changes in magnetoelastic materials;applications of thin film trielectrode electroluminescent display devices for automotive vehicles;and the history and development of coated contrast enhancement filters for cockpit displays.

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SIC LIGHTWEIGHT TELESCOPES FOR advanced SPACE applications .2. STRUCTURES TECHNOLOGY 2

SIC LIGHTWEIGHT TELESCOPES FOR ADVANCED SPACE APPLICATIONS ....

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CONF ON SURVEILLANCE TECHNOLOGIES 2

作者： ANAPOL, MI HADFIELD, P TUCKER, T Sensor Systems Group Inc. (United States)

ISBN: (纸本)0819408581

A critical technology area for lightweight SiC-based telescope systems is the structural integrity and thermal stability over spaceborne environmental launch and thermal operating conditions. Note, it is highly desirable to have an inherently athermal design of both SiC mirrors and structure. SSG has developed an 8 inch diameter SiC telescope system for brassboard level optical and thermal testing. The brassboard telescope has demonstrated less than 0.2 waves P-V in the visible wavefront change over +50 C to -200 C temperature range. SSG has also fabricated a SiC truss structural assembly and successfully qualified this hardware at environmental levels greater than 3 times higher than normal Delta, Titan, and ARIES launch loads. SSG is currently developing two SiC telescopes; an 20 cm diameter off-axis 3 mirror re-imaging and a 60 cm aperture on-axis 3 mirror re-imager. Both hardware developments will be tested to flight level environmental, optical, and thermal specifications.

关键词： Silicon carbide Space telescopes Telescopes Mirrors Optical fabrication Surveillance Thermography Wavefronts Mirror mounts Mirror structures

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SIC LIGHTWEIGHT TELESCOPES FOR advanced SPACE applications .1. MIRROR TECHNOLOGY 2

SIC LIGHTWEIGHT TELESCOPES FOR ADVANCED SPACE APPLICATIONS ....

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CONF ON SURVEILLANCE TECHNOLOGIES 2

作者： ANAPOL, MI HADFIELD, P Sensor Systems Group Inc. (United States)

ISBN: (纸本)0819408581

A SiC based telescope is an extremely attractive emerging technology which offers the lightweight and stiffness features of beryllium, the optical performance of glass to diffraction limited visible resolution, superior optical/thermal stability to cryogenic temperatures, and the cost advantages of an aluminum telescope. SSG has developed various SiC mirrors with and without a silicon coating and tested these mirrors over temperature ranges from +50 C to -250 C. Our test results show less than 0.2 waves P-V in visible wavefront change and no hysteresis over this wide temperature range. Several SSG mirrors are representative of very lightweight SiC/Si mirrors including (1) a 9 cm diameter, high aspect ratio mirror weighing less than 30 grams and (2) a 23 cm diameter eggcrated mirror weighing less than 400 grams. SSG has also designed and analyzed a 0.6 meter SiC based, on axis, three mirror reimaging telescope in which the primary mirror weighs less than 6 kg and a 0.5 meter GOES-like scan mirror. SSG has also diamond turned several general aspheric SiC/Si mirrors with excellent cryo optical performance.

关键词： Mirrors Silicon carbide Space telescopes Telescopes Beryllium Silicon Wavefronts Diamond Polishing Temperature metrology

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Dynamic IR scene projection using the Hughes liquid crystal light valve

Dynamic IR scene projection using the Hughes liquid crystal ...

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Proceedings of the Conference on Liquid Crystal Materials, Devices, and applications

作者： Forber, Richard A. Au, Anson Efron, Uzi Sayyah, Keyvan Wu, Shin T. Goldsmith ii, George C. Hughes Research Labs. Malibu CA USA

ISBN: (纸本)0819408190

This paper reviews recent development and application of the infrared version of the liquid crystal light valve (LCLV). We describe delivered IR image projectors for advanced end-to-end laboratory testing of IR seeker and sensor systems. System performance characteristics are given. A newly developed version of the device has much higher contrast with low IR background image capability.

关键词： Liquid crystals

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Potential for integrated optical circuits in advanced aircraft with fiber optic control and monitoring systems

Potential for integrated optical circuits in advanced aircra...

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Integrated Optics and Optoelectronics ii

作者： Baumbick, Robert Natl Aeronautics and Space Administration Cleveland United States

Fiber optic technology is expected to be used in future advanced weapons platforms as well as commercial aerospace applications. Fiber optic waveguides will be used to transmit noise free, high speed data between a multitude of computers as well as audio and video information to the flight crew. Passive optical sensors connected to control computers with optical fiber interconnects will serve both control and monitoring functions. Implementation of fiber optic technology has already begun. Both the military and NASA have several programs in place. A cooperative program, called FOCSI (Fiber Optic Control System Integration), between NASA Lewis and the NAVY to build, environmentally test and flight demonstrate sensor systems for propulsion and flight control systems is currently underway. Integrated Optical Circuits (IOC's) are also being given serious consideration for use in advanced aircraft systems. IOC's will result in miniaturization and localization of components to generate, detect optical signals and process them for use by the control computers. Manufacturing technology developed for microelectronic integrated circuits applied to IOC's will result in cost effective manufacturing. This paper reviews the current FOCSI program and describes the potential role of IOC's in FOCSI applications.

关键词： Aircraft

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applications of smart structures in the control of chaotic vibrations

Applications of smart structures in the control of chaotic v...

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Winter Annual Meeting of the American Society of Mechanical Engineers

作者： Hall ii, E.K. Hanagud, S.V. Georgia Inst of Technology Atlanta United States

ISBN: (纸本)0791808580

The purpose of this paper is to demonstrate methods in which smart materials may be used to control a special class of nonlinear vibrations termed chaotic vibrations. This objective will be met through an analytical study of a multidegree of freedom model of a buckled beam which is subjected to a periodic loading. For certain load amplitudes the beam responds chaotically. Two types of control methodologies are examined. In the first, piezoceramic sensors are used to incorporate a feedback linearization technique and eliminate any nonlinear effects in the response of the beam, thus eliminating any chaotic responses. The second methodology then uses output feedback of piezoceramic sensor signals to piezoceramic actuators to suppress chaotic oscillations. Both methods are shown to be effective in the suppression of chaotic oscillations, and problem areas and future applications are discussed.

关键词： Vibrations

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