Showing papers by "Raytheon published in 2003"

Hyperion, a space-based imaging spectrometer

Abstract: The Hyperion Imaging Spectrometer was the first imaging spectrometer to routinely acquire science-grade data from Earth orbit. Instrument performance was validated and carefully monitored through a combination of calibration approaches: solar, lunar, earth (vicarious) and atmospheric observations complemented by onboard calibration lamps and extensive prelaunch calibration. Innovative techniques for spectral calibration of space-based sensors were also tested and validated. Instrument performance met or exceeded predictions including continued operation well beyond the planned one-year program.

Antiwindup for stable linear systems with input saturation: an LMI-based synthesis

Abstract: This paper considers closed-loop quadratic stability and L/sub 2/ performance properties of linear control systems subject to input saturation. More specifically, these properties are examined within the context of the popular linear antiwindup augmentation paradigm. Linear antiwindup augmentation refers to designing a linear filter to augment a linear control system subject to a local specification, called the "unconstrained closed-loop behavior." Building on known results on H/sub /spl infin// and LPV synthesis, the fixed order linear antiwindup synthesis feasibility problem is cast as a nonconvex matrix optimization problem, which has an attractive system theoretic interpretation: the lower bound on the achievable L/sub 2/ performance is the maximum of the open and unconstrained closed-loop L/sub 2/ gains. In the special cases of zero-order (static) and plant-order antiwindup compensation, the feasibility conditions become (convex) linear matrix inequalities. It is shown that, if (and only if) the plant is asymptotically stable, plant-order linear antiwindup compensation is always feasible for large enough L/sub 2/ gain and that static antiwindup compensation is feasible provided a quasi-common Lyapunov function, between the open-loop and unconstrained closed-loop, exists. Using the solutions to the matrix feasibility problems, the synthesis of the antiwindup augmentation achieving the desired level of L/sub 2/ performance is then accomplished by solving an additional LMI.

Curse of dimensionality and particle filters

Abstract: Particle filtering (PF) is a new class of algorithms to solve the nonlinear filtering problem. These PFs are very general and easy to code. The main issue with PF is the large computational complexity. In particular, for typical low dimensional tracking problems, the PF requires 2 to 6 orders of magnitude more computer throughput than the extended Kalman filter, to achieve the same accuracy. It has been asserted that the PF avoids the curse of dimensionality, but there is no formula or theorem that bounds or, approximates the computational complexity of the PF as a function of dimension (d). In this paper, we derive a simple back-of-the-envelope formula that explains why a carefully designed PF should mitigate the curse of dimensionality for certain filtering problems, but the PF does not avoid the curse of dimensionality in general. We also show experimental results which c o n f i i our simple formula. We consider this a triumph of theory. This new theory hinges on the fact that the volume of the d dimensional unit sphere is an amazingly small fraction of the volume of the d dimensional unit cube, for large d.

Energy Contribution of Octanoate to Intact Rat Brain Metabolism Measured by 13C Nuclear Magnetic Resonance Spectroscopy

Abstract: Glucose is the dominant oxidative fuel for brain, but studies have indicated that fatty acids are used by brain as well. We postulated that fatty acid oxidation in brain could contribute significantly to overall energy usage and account for non-glucose-derived energy production. [2,4,6,8-13C4]octanoate oxidation in intact rats was determined by nuclear magnetic resonance spectroscopy. We found that oxidation of 13C-octanoate in brain is avid and contributes approximately 20% to total brain oxidative energy production. Labeling patterns of glutamate and glutamine were distinct, and analysis of these metabolites indicated compartmentalized oxidation of octanoate in brain. Examination of liver and blood spectra revealed that label from 13C-octanoate was incorporated into glucose and ketones, which enabled calculation of its overall energy contribution to brain metabolism: glucose (predominantly unlabeled) and 13C-labeled octanoate can account for the entire oxidative metabolism of brain. Additionally, flux through anaplerotic pathways relative to tricarboxylic acid cycle flux (Y) was calculated to be 0.08 +/- 0.039 in brain, indicating that anaplerotic flux is significant and should be considered when assessing brain metabolism. Y was associated with the glutamine synthesis compartment, consistent with the view that anaplerotic flux occurs primarily in astrocytes.

Spaceborne soil moisture estimation at high resolution: a microwave-optical/IR synergistic approach

Abstract: An approach is evaluated for the estimation of soil moisture at high resolution using satellite microwave and optical/infrared (IR) data. This approach can be applied to data acquired by the Visible/Infrared Imager Radiometer Sensor Suite (VIIRS) and a Conical Scanning Microwave Imager/Sounder (CMIS), planned for launch in the 2009–2010 time frame under the National Polar-Orbiting Operational Environmental Satellite System (NPOESS). The approach for soil moisture estimation involves two steps. In the first step, a passive microwave remote sensing technique is employed to estimate soil moisture at low resolution (∼25 km). This involves use of a simplified radiative transfer model to invert dual-polarized microwave brightness temperature. In the second step, the microwave-derived low-resolution soil moisture is linked to the scene optical/IR parameters, such as Normalized Difference Vegetation Index (NDVI), surface albedo, and Land Surface Temperature (LST). The linking is based on the ‘Universal Triangle’ ...

Miniature Thermal Emission Spectrometer for the Mars Exploration Rovers

Abstract: [1] The Miniature Thermal Emission Spectrometer (Mini-TES) will provide remote measurements of mineralogy and thermophysical properties of the scene surrounding the Mars Exploration Rovers and guide the rovers to key targets for detailed in situ measurements by other rover experiments. The specific scientific objectives of the Mini-TES investigation are to (1) determine the mineralogy of rocks and soils, (2) determine the thermophysical properties of selected soil patches, and (3) determine the temperature profile, dust and water-ice opacity, and water vapor abundance in the lower atmospheric boundary layer. The Mini-TES is a Fourier Transform Spectrometer covering the spectral range 5–29 μm (339.50 to 1997.06 cm−1) with a spectral sample interval of 9.99 cm−1. The Mini-TES telescope is a 6.35-cm-diameter Cassegrain telescope that feeds a flat-plate Michelson moving mirror mounted on a voice-coil motor assembly. A single deuterated triglycine sulfate (DTGS) uncooled pyroelectric detector with proven space heritage gives a spatial resolution of 20 mrad; an actuated field stop can reduce the field of view to 8 mrad. Mini-TES is mounted within the rover's Warm Electronics Box and views the terrain using its internal telescope looking up the hollow shaft of the Pancam Mast Assembly (PMA) to the fixed fold mirror and rotating elevation scan mirror in the PMA head located ∼1.5 m above the ground. The PMA provides a full 360°of azimuth travel and views from 30° above the nominal horizon to 50° below. An interferogram is collected every two seconds and transmitted to the Rover computer, where the Fast Fourier Transform, spectral summing, lossless compression, and data formatting are performed prior to transmission to Earth. Radiometric calibration is provided by two calibration V-groove blackbody targets instrumented with platinum thermistor temperature sensors with absolute temperature calibration of ±0.1°C. One calibration target is located inside the PMA head; the second is on the Rover deck. The Mini-TES temperature is expected to vary diurnally from −10 to +30°C, with most surface composition data collected at scene temperatures >270 K. For these conditions the radiometric precision for two-spectra summing is ±1.8 × 10−8 W cm−2 sr−1/cm−1 between 450 and 1500 cm−1, increasing to ∼4.2 × 10−8 W cm−2 sr−1/cm−1 at shorter (300 cm−1) and longer (1800 cm−1) wave numbers. The absolute radiance error will be <5 × 10−8 W cm−2 sr−1/cm−1, decreasing to ∼1 × 10−8 W cm−2 sr−1/cm−1 over the wave number range where the scene temperature will be determined (1200–1600 cm−1). The worst-case sum of these random and systematic radiance errors corresponds to an absolute temperature error of ∼0.4 K for a true surface temperature of 270 K and ∼1.5 K for a surface at 180 K. The Mini-TES will be operated in a 20-mrad panorama mode and an 8-mrad targeted mode, producing two-dimensional rasters and three-dimensional hyperspectral image cubes of varying sizes. The overall Mini-TES envelope size is 23.5 × 16.3 × 15.5 cm, and the mass is 2.40 kg. The power consumption is 5.6 W average. The Mini-TES was developed by Arizona State University and Raytheon Santa Barbara Remote Sensing.

Wideband phased array radiator

Abstract: Raytheon has developed a novel wide-band, dual-polarized, element with excellent cross-polarization isolation to populate the AMRFC high band transmit array. The electrically short crossed notch (ESCN) element consists of an orthogonal pair of tapered crossed-notch radiators with a balanced feed to increase polarization purity. The ECSN provides excellent polarization performance vs. scan (better than current notch capabilities). The measured co-pol and x-pol performance of the embedded element in the E-, H-, and diagonal planes and the swept gain performance will be discussed. Also discussed will be the modeling techniques used to design this wideband radiator.

Dynamic wireless resource utilization

Abstract: In one embodiment, a method for dynamic wireless resource utilization includes monitoring a wireless communication resource, generating wireless communication resource data; using the wireless communication resource data, predicting the occurrence of on or more holes in a future time period; generating hole prediction data; using the hole prediction data, synthesizing one or more wireless communication channels from the one or more predicted holes; generating channel synthesis data; receiving data reflecting feedback from a previous wireless communication attempt and data reflecting a network condition; according to the received data and the channel synthesis data, selecting a particular wireless communication channel from the one more synthesized wireless communication channels; generating wireless communication channel selection data; using the wireless communication channel selection data, instructing a radio unit to communicate using the selected wireless communication channel; and instructing the radio unit to discontinue use of the selected wireless communication channel after the communication has been completed.

Heat shield panels for use in a combustor for a gas turbine engine

Abstract: The present invention relates to heat shield panels or liners to be used in combustors for gas turbine engines. The heat shield panels each comprise a hot side and a cold side and at least one isolated cooling chamber on the cold side. Each cooling chamber has a plurality of cooling film holes for allowing a coolant, such as air, to flow from the cold side to the hot side. A combustor having an arrangement of heat shield panels or liners is also described.

Low profile wideband antenna array

Abstract: A phased array antenna (10) (Figure 6) having a low profile (approximately 1/8 wavelength) wide bandwidth (approximately 50%). The invention teaches making such an antenna using open channel resonators (22) and monopole wave launchers (110). The wave launchers may conveniently be made on circuit card assemblies (106) with strip lines (110) that mimic coaxial cable monopole wave launchers. The channel resonators (22) may be made in sections that are connected to the circuit card assemblies. The circuit card assemblies (106) have plated through holes that trace the edges of the resonator sections to provide electrical continuity.

Increased salivary cortisol concentrations during chronic alcohol intoxication in a naturalistic clinical sample of men

Abstract: Background: Cortisol, the primary glucocorticoid in humans, is intimately involved in the regulation of such varied and critical biological processes as emotion, cognition, reward, immune functioning, and energy utilization. A persistent increase in cortisol concentration as a result of chronic intoxication could therefore result in alcohol-related disorders such as sleep disruption, cognitive deficits, diabetes, and mood disturbances. Although moderate levels of acute alcohol ingestion are reported to produce an increase in cortisol levels, it is uncertain whether cortisol remains persistently increased during long-term chronic intoxication. Methods: Salivary cortisol and breath alcohol concentrations (BAC) were obtained on 73 subjects with primary alcohol dependence on initial presentation for treatment and 22 alcohol-dependent subjects participating in a residential treatment program. Results: Both intoxicated alcohol-dependent subjects (n= 38) and nonintoxicated subjects in acute alcohol withdrawal (n= 30) demonstrated significantly increased salivary cortisol concentrations compared with abstinent subjects (n= 27; p 100 mg/dl) but were similar to subjects with lower levels of intoxication (BAC, 10–100 mg/dl). Conclusions: Chronic alcohol-dependent subjects experience continuously increased concentrations of cortisol during both intoxication and withdrawal. Increased levels of cortisol during chronic intoxication seem to progressively increase with the onset of withdrawal. This suggests a daily cycle of hypercortisolemia during the active drinking phase, with further increases on the cessation of drinking and the emergence of withdrawal symptoms. Persistently increased levels of cortisol may extract a costly allostatic load, resulting in significant central nervous system and peripheral organ morbidity.

Micro-electro-mechanical switch, and methods of making and using it.

Abstract: A micro-electro-mechanical (MEMS) switch (10, 110) has an electrode (22, 122) covered by a dielectric layer (23, 123), and has a flexible conductive membrane (31, 131) which moves between positions spaced from and engaging the dielectric layer. At least one of the membrane and dielectric layer has a textured surface (138) that engages the other thereof in the actuated position. The textured surface reduces the area of physical contact through which electric charge from the membrane can tunnel into and become trapped within the dielectric layer. This reduce the amount of trapped charge that could act to latch the membrane in its actuated position, which in turn effects a significant increase in the operational lifetime of the switch.

An adaptive air interface waveform

Abstract: In one embodiment, a method for generating an adaptive air interface waveform includes generating a waveform that includes a variable carrier frequency and variable bandwidth signal. The variable bandwidth signal includes one or more subcarriers that are dynamically placeable over a range of frequencies, and each subcarrier is separately modulated according to a direct sequence (DS) spread spectrum (SS) technique. The waveform has an embedded pilot usable to optimize one or more spectrum efficiencies of the waveform. A modulation constellation, a code rate, and a code length of the generated waveform are adapted according to an available spectrum and one or more sub-carrier conditions.

Calibration of the Orsted vector magnetometer

Abstract: The vector fluxgate magnetometer of the Orsted satellite is routinely calibrated by comparing its output with measurements of the absolute magnetic intensity from the Overhauser instrument, which is the second magnetometer of the satellite We describe the method used for and the result obtained in that calibration Using three years of data the agreement between the two magnetometers after calibration is 033 nT rms (corresponding to better than ± 1 nT for 98% of the data, and better than ± 2 nT for 9994% of the data) We also report on the determination of the transformation between the magnetometer coordinate system and the reference system of the star imager This is done by comparing the magnetic and attitude measurements with a model of Earth’s magnetic field The Euler angles describing this rotation are determined in this way with an accuracy of better than 4 arcsec

Dynamic rule generation for an enterprise intrusion detection system

Abstract: A method for dynamically generating rules for an enterprise intrusion detection system comprises receiving a packet flow from a sensor. The packet flow is dynamically processed to detect if the packet flow represents an attack on the enterprise system. A response message is automatically generated in response to the attack, the response message comprising a signature to identify the attack. The response message is automatically communicated to a response message file, the response message file comprising at least one response message.

Effects of spectrometer band pass, sampling, and signal-to-noise ratio on spectral identification using the Tetracorder algorithm

Abstract: [1] Estimates of spectrometer band pass, sampling interval, and signal-to-noise ratio required for identification of pure minerals and plants were derived using reflectance spectra convolved to AVIRIS, HYDICE, MIVIS, VIMS, and other imaging spectrometers. For each spectral simulation, various levels of random noise were added to the reflectance spectra after convolution, and then each was analyzed with the Tetracorder spectral identification algorithm [Clark et al., 2003]. The outcome of each identification attempt was tabulated to provide an estimate of the signal-to-noise ratio at which a given percentage of the noisy spectra were identified correctly. Results show that spectral identification is most sensitive to the signal-to-noise ratio at narrow sampling interval values but is more sensitive to the sampling interval itself at broad sampling interval values because of spectral aliasing, a condition when absorption features of different materials can resemble one another. The band pass is less critical to spectral identification than the sampling interval or signal-to-noise ratio because broadening the band pass does not induce spectral aliasing. These conclusions are empirically corroborated by analysis of mineral maps of AVIRIS data collected at Cuprite, Nevada, between 1990 and 1995, a period during which the sensor signal-to-noise ratio increased up to sixfold. There are values of spectrometer sampling and band pass beyond which spectral identification of materials will require an abrupt increase in sensor signal-to-noise ratio due to the effects of spectral aliasing. Factors that control this threshold are the uniqueness of a material's diagnostic absorptions in terms of shape and wavelength isolation, and the spectral diversity of the materials found in nature and in the spectral library used for comparison. Array spectrometers provide the best data for identification when they critically sample spectra. The sampling interval should not be broadened to increase the signal-to-noise ratio in a photon-noise-limited system when high levels of accuracy are desired. It is possible, using this simulation method, to select optimum combinations of band-pass, sampling interval, and signal-to-noise ratio values for a particular application that maximize identification accuracy and minimize the volume of imaging data.

Closely coupling amplifiers to antennas on a base station tower

Abstract: The present invention relates to a transmit diversity antenna system employing active antenna electronics (with both receive and transmit amplifiers distributed among the elements of the antenna), polarization diversity on receive, and polarity diversity along with time delay diversity on transmit. The combination of these three techniques, in wireless communications applications, improves the efficiency and performance of both the transmitted and received signals at a base station, as well as the received signal at the mobile. In practice the present invention enables a substantially "balanced link" to exist between the base station and a mobile.

Miniaturized imaging device with integrated circuit connector system

Abstract: A miniaturized imaging device and method of viewing small luminal cavities are described. The imaging device can be used as part of a catheter, and can include a lens, an SSID including an imaging array optically coupled to the lens; an umbilical including a conductive line; and an adaptor configured to support the lens and provide electrical communication between the SSID and conductive line. Alternatively, the adaptor can be a rigid adaptor configured to provide electrical communication between the SSID and the conductive line through a conductive path. The conductive path can be configured along multiple contiguous surfaces of the adaptor such that the SSID is electrically coupled to the conductive path at a first surface, and the conductive line is electrically coupled to the conductive path at a second surface.

System and techniques to bind information objects to security labels

Abstract: A method to providing multilevel security for a data object requested by a workstation user includes providing a security label for the data object, associating security rules including a security clearance level for the data object with the security label, binding the security label to the data object, validating the correctness of the security label, associating the user's security clearance level with at least one user certificate, verifying the at least one user certificate, and determining whether the user has clearance to receive the requested data.

Antenna configurations for reduced radar complexity

Abstract: A transmit and receiving system including a first array including at least one antenna element disposed to provide a transmit antenna. The system further includes a second array having a second different plurality of antenna elements disposed to provide a receive antenna. The first array is coupled to a switching system, which is operative to selectively form at least one transmit beam. The second array is coupled to a beam combining system, which is operative to selectively form a plurality of receive beams.

Thermal barrier coatings with low thermal conductivity

Abstract: A ceramic material having particular utility as a thermal insulating or thermal barrier coating on metallic substrates is provided. The ceramic material broadly comprises at least one oxide and the balance comprising a first oxide selected from the group consisting of zirconia, ceria, and hafnia. The at least one oxide has a formula A 2 O 3 where A is selected from the group consisting of La, Pr, Nd, Sm, Eu, Tb, In, Sc, Y, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof. The present invention also broadly relates to an article having a metal substrate and a thermal barrier coating as discussed above.

Single-event effects ground testing and on-orbit rate prediction methods: the past, present, and future

Abstract: Over the past 27 years, or so, increased concern over single-event effects (SEEs) in spacecraft systems has resulted in research, development, and engineering activities centered around a better understanding of the space radiation environment, SEE predictive methods, ground test protocols, and test facility developments. This research has led to fairly well developed methods for assessing the impact of the space radiation environment on systems that contain SEE sensitive devices and the development of mitigation strategies either at the system or device level. However, as new technology has emerged, these ground test and predictive methods have certain short falls.

Symplectic semifield planes and ℤ₄–linear codes

Abstract: There are lovely connections between certain characteristic 2 semifields and their associated translation planes and orthogonal spreads on the one hand, and Z 4 -linear Kerdock and Preparata codes on the other. These interrelationships lead to the construction of large numbers of objects of each type. In the geometric context we construct and study large numbers of nonisomorphic affine planes coordinatized by semifields; or, equivalently, large numbers of non-isotopic semifields: their numbers are not bounded above by any polynomial in the order of the plane. In the coding theory context we construct and study large numbers of Z 4 -linear Kerdock and Preparata codes. All of these are obtained using large numbers of orthogonal spreads of orthogonal spaces of maximal Witt index over finite fields of characteristic 2. We also obtain large numbers of boring affine planes in the sense that the full collineation group fixes the line at infinity pointwise, as well as large numbers of Kerdock codes boring in the sense that each has as small an automorphism group as possible. The connection with affine planes is a crucial tool used to prove inequivalence theorems concerning the orthogonal spreads and associated codes, and also to determine their full automorphism groups.

Heavy-ion broad-beam and microprobe studies of single-event upsets in 0.20-/spl mu/m SiGe heterojunction bipolar transistors and circuits

Abstract: Combining broad-beam circuit level single-event upset (SEU) response with heavy ion microprobe charge collection measurements on single silicon-germanium heterojunction bipolar transistors improves understanding of the charge collection mechanisms responsible for SEU response of digital SiGe HBT technology. This new understanding of the SEU mechanisms shows that the right rectangular parallel-piped model for the sensitive volume is not applicable to this technology. A new first-order physical model is proposed and calibrated with moderate success.