| On Improving the Convergence of the Solution of a System of Linear Equations |
AUG 2005 |
22 pages |
| Authors:
Surendra Singh; Klaus Halterman; J. M. Elson; TULSA UNIV OK DEPT OF ELECTRICAL ENGINEERING
|
 | The computation of electromagnetic scattering from a nanowire requires the solution of a system of linear equations of the form, Ax=b, where the dimension of the matrix A increases with the number of unknowns. Previously, we had implemented a bi-conjugate gradient algorithm to iteratively solve this system of equations. However, this method converges very slowly when the convergence criterion is made stringent. An improved version of the algorithm, namely stabilized ... |
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| SAS Imaging and the Sea Surface Bounce Path |
29 JUL 2005 |
14 pages |
| Authors:
Peter H ; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| Modeling and interpretation of SAS measurements taken during SAXO4 experiment in conducted near Panama City, Florida (fall 2004), is completed. Both data and simulation show how multipath interaction with the sea surface delivers the SAS transmit waveform roundtrip, and causes three time horizons for a single target located near the sea surface. The results shed light on the role of sea surface interaction in SAS methodologies whenever they are applied ... |
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| Evaluation of Acoustic Propagation Paths into the Human Head |
25 JUL 2005 |
23 pages |
| Authors:
William D. O'Brien Jr.; Yuhui Liu; ILLINOIS UNIV AT URBANA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| The overall goal of this research was to develop an acoustic wave propagation model using well-understood and documented computational techniques that track and quantify an air-borne incident acoustic wave propagated around, into and in the human head. The model purpose served two purposes: (1) determine alternate acoustic propagation paths to the cochlear shell that exist besides the normal air-borne acoustic propagation path (eardrum-ossical path) through the auditory canal and (2) ... |
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| An Analysis of Gradient-Induced Distortion in Dual Beam ATI Systems for Vector Surface Current Mapping |
25 JUL 2005 |
5 pages |
| Authors:
Mark A. Sletten; NAVAL RESEARCH LAB WASHINGTON DC
|
| This paper summarizes an analysis of gradient-induced distortions in the vector surface current estimates generated by dual-beam, along-track interferometric SAR systems. In such systems, interferograms from two squinted beams, one squinted forward of broadside and the other aft, are combined to measure the full surface current vector with only a single aircraft pass. However, in the presence of significant current gradients, an effect akin to velocity-bunching can cause distortion in ... |
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| The Global Precipitation Measurement (GPM) Microwave Imager (GMI) Instrument: Role, Performance, and Status |
25 JUL 2005 |
5 pages |
| Authors:
S. W. Bidwell; G. M. Flaming; J. F. Durning; E. A. Smith; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GREENBELT MD GODDARD SPACE FLIGHT CENTER
|
| The Global Precipitation Measurement (GPM) Microwave Imager (GMI) instrument is a multi-channel, conical-scanning, microwave radiometer serving an essential role in the near-global-coverage and frequent-revisit-time requirements of GPM. As a part of its contribution to GPM, NASA will provide a GMI instrument and a spacecraft for the Core observatory and is considering the acquisition of a second GMI instrument for placement aboard a constellation spacecraft with a payload and orbit to ... |
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| Texture Models for High-Resolution Ocean Microwave Imagery |
25 JUL 2005 |
5 pages |
| Authors:
Victor Raizer; ZEL TECHNOLOGIES LLC HAMPTON VA
|
| Computer simulations of ocean passive microwave images and texture features are developed in the context of high-resolution radiometric observations. The technique is based on statistical and deterministic characterizations of spatial-variable fields (image scenes) containing ensembles of different radio-hydrophysical factors -- surface roughness, foam, whitecap, spray, and bubbles. The corresponding microwave contributions are calculated using available hydrodynamic-electromagnetic models. In particular, we employ the well known resonance model for simulations of low-contrast ... |
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| Impact on Sea Surface Salinity Retrieval of Multisource Auxiliary Data within the SMOS Mission |
25 JUL 2005 |
5 pages |
| Authors:
Roberto Sabia; Adriano Camps; Nicolas Reul; Merce Vall-llossera; UNIVERSITAT POLITECNICA DE CATALUNYA BARCELONA (SPAIN) DEPT OF SIGNAL THEORY AND COMMUNICATIONS
|
| Aiming to provide Sea Surface Salinity (SSS) maps with a spatio-temporal averaged accuracy of 0.1 psu, the SMOS community is increasingly focusing on the determination of a robust inversion scheme to enable SSS retrieval from L-band brightness temperature data. In the framework of the Synergetic Aspects and Auxiliary Data Concepts for Sea Surface Salinity Measurements from Space project, efforts have been oriented towards a quantitative analysis of SSS retrieval once ... |
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| Exploration of the Lower Atmosphere with Millimeter-Wave Radar |
25 JUL 2005 |
5 pages |
| Authors:
Mai T. Ngo; George J. Linde; WinJou J. Cheung; NAVAL RESEARCH LAB WASHINGTON DC RADAR DIV
|
| With the high peak power and large antenna gain of the WARLOC W-band (94 GHz) radar, clear-air radar returns from the lower atmosphere, which have no visible underlying scattering mechanism, have been observed. Due to their close resemblance to classical sea spikes from the sea surface scatter, the unknown phenomena are being referred to as air spikes. In this paper, a brief description of the high power WARLOC radar and ... |
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| Low Phase Noise Fiber Optics Links for Space Applications |
13 JUL 2005 |
9 pages |
| Authors:
Bertrand Onillon; Stephanie Constant; Gianandrea Quardi; Benoit Benazet; Olivier Llopis; CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE TOULOUSE (FRANCE) LAB DE METALLURGIE PHYSIQUE
|
| This paper summarises the results obtained on different systems dedicated to the optical distribution of high spectral purity RF and microwave signals in a satellite payload or towards the elements of an active antenna. First, the interest of the photo-oscillator receiver for these applications in the RF frequency range is pointed out. Then, different emitter configurations are investigated in the microwave range . Finally, an application of these low phase ... |
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| Technology Disruptions in Future Communication Payloads (Technologies de rupture pour futures charges utiles de telecommunications) |
13 JUL 2005 |
|
| Authors:
Jean-Didier Gayrard; ALCATEL SPACE TOULOUSE (FRANCE)
|
 | The future market of satellite telecommunications will be shaped by four main trends: democratization, regionalization, digitalization, and the use of higher frequency bands. To cope with the economic and technical demands of the market and to compete with terrestrial networks, operators and manufacturers will need to upgrade their satellites. The evolution of satellite communications could go one of three ways: gigantism, adaptation, or modularity. Any of these ways will require ... |
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| Internet Switching by Satellite: An Ultra Fast Processor with Radio Burst Switching |
13 JUL 2005 |
|
| Authors:
Celine Haardt; Nicolas Couville; ALCATEL SPACE INDUSTRIES TOULOUSE (FRANCE)
|
| This paper introduces a new switching approach for satellites involved in routing statistical traffic, such as Internet Protocol (IP) data. Inherited from the optical domain, Radio Burst Switching (RBS) can combine a coarse switching granularity (such as circuit switching) with statistical multiplexing (such as packet switching) to better cope with the increasing bandwidth demands of Internet traffic and the need for high connectivity. RBS allows for packet switching missions in ... |
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| Light and Matter Wave Scattering in an Optically Trapped Fermi Gas |
12 JUL 2005 |
12 pages |
| Authors:
J. E. Thomas; DUKE UNIV DURHAM NC DEPT OF PHYSICS
|
| All-optical trapping methods are used to produce a strongly-interacting Fermi gas near a Feshbach resonance. The gas has universal properties enabling table top experiments to explore diverse fermionic systems ranging from high temperature superconductors to nuclear matter neutron stars and quark-gluon plasmas. |
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| Electromagnetic Design Techniques Enabling Control of the RFID Supply Chain |
06 JUL 2005 |
28 pages |
| Authors:
Robert G. Hohlfeld; WAVELET TECHNOLOGIES INC ATTLEBORO MA
|
| This report summarizes progress in the SBIR Phase I project "Electromagnetic Design Techniques Enabling Control of the RFID Supply Chain". During this project Wavelet Technologies, Inc. (WTI) has extended its genetic optimization program to include a variety of additional antenna geometries, worked out means for translating antenna designs to a form suitable for prototype fabrication, acquired RFID chips sufficient to demonstrate component independence, produced and tested genetically optimized RFID tag ... |
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| A Model to Predict Transient Dielectric-Charging Effects in RF MEMS Capacitive Switches |
JUL 2005 |
6 pages |
| Authors:
Xiaobin Yuan; James C. M. Hwang; David I. Forehand; Charles L. Goldsmith; LEHIGH UNIV BETHLEHEM PA
|
| Wafer-level micro-encapsulation is an innovative, low-cost, wafer-level packaging methods for encapsulating RF MEMS switches. This zero-level packaging technique has demonstrated 0.04 dB package insertion loss at 35 GHz. This article overviews the processes, measurements, and testing methods used for determining the integrity and performance of individual encapsulated RF MEMS packages. |
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| Characterization of the Environment During SAX04: Preliminary Results |
JUL 2005 |
9 pages |
| Authors:
Allen H. Reed; Bernard P. Boudreau; Chris Algar; Yoko Furukawa; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS SEAFLOOR SCIENCES DIRECTORATE
|
| The Sediment Acoustic Experiment (SAXO4) was conducted on a sandy sediment 1- km offshore of Ft. Walton Beach, Florida, September-November, 2904. The objectives of SAXO4 were to provide a fundamental understanding of high frequency acoustic-bottom interactions sufficient to predict acoustic scattering from the seafloor, penetration of acoustic energy into the seafloor, and propagation of acoustic energy within the seafloor. For these acoustic topics a thorough characterization of seafloor properties is ... |
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| Improved Performance of MEMS Based Filters |
30 JUN 2005 |
10 pages |
| Authors:
Kimberly L. Turner; Steven W. Shaw; CALIFORNIA UNIV SANTA BARBARA DEPT OF MECHANICAL AND ENVIRONMENTAL ENGINEERING
|
| As the demand for wireless communications technology continues to increase, so too does the demand for effective and efficient filters, as these devices, which pass signals with frequency components inside a specific bandwidth while attenuating those outside of it, are often integral components of such technology. Micro-scale components are more desirable than their more conventional counterparts primarily due to their size, low power consumption, and ease of integration with electrical ... |
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| The Economic Importance of Adequate Aeronautical Telemetry Spectrum |
23 JUN 2005 |
|
| Authors:
Carolyn A. Kahn; MITRE CORP BEDFORD MA
|
| INTRODUCTION: (1) The flight test community faces a telemetry spectrum crunch; (2) Amount of spectrum now allocated for ATM is not sufficient to meet needs, and requirements have been steadily growing; (3) ATM spectrum is vital to both commercial and military flight testing; (4) There are economic implications associated with the allocation of spectrum for ATM; (5) Economic considerations are important to the proposal currently before the ITU: Agenda Item ... |
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| Frequency Domain Steady-state Simulation of Oscillators |
08 JUN 2005 |
125 pages |
| Authors:
Xiaochun Duan; OREGON STATE UNIV CORVALLIS SCHOOL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| The focus of this work is on developing algorithms for frequency domain steady-state analysis of oscillators. Convergence problems associated with the frequency domain harmonic balance simulation of oscillators have been examined. Globally convergent homotopy methods have been combined with the harmonic balance method for robust high-Q oscillator simulation. Various homotopy options are evaluated leading to an algorithm that is applicable to a wide variety of oscillator circuits. Two new approaches ... |
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| Development of a Class-Specific Module for Hyperbolic, Frequency-Modulated Signals |
07 JUN 2005 |
24 pages |
| Authors:
Brian F. Harrison; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| The class-specific method (CSM) is a novel technique for signal classification. CSM operates by computing low-dimensional feature sets, each tailored to a given signal class. In this manner, CSM avoids the difficulties inherent with classical Bayesian signal classification methods that attempt to estimate probability distributions in high-dimensional feature space. The fundamental building block of a CSM classifier is the feature extraction module. Each module is designed for a specific signal ... |
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| Primary and Secondary Superresolution by Data Inversion (Postprint) |
06 JUN 2005 |
16 pages |
| Authors:
Charles Matson; David W. Tyler; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| Super resolution by data inversion is the extrapolation of measured Fourier data to regions outside the measurement bandwidth using post processing techniques. Here we characterize super resolution by data inversion for objects with finite support using the twin concepts of primary and secondary super resolution, where primary super resolution is the essentially unbiased portion of the super resolution data and secondary super resolution is the remainder. We show that this ... |
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| Calculated Out-of-Plane Transmission Loss for Photonic-Crystal Slab Waveguides |
01 JUN 2005 |
4 pages |
| Authors:
Wan Kuang; Cheolwon Kim; Andrew Stapleton; Woo J. Kim; John D. O'Brien; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF ELECTRICAL ENGINEERING AND ELECTROPHYSICS
|
| A fully three-dimensional finite-difference time domain numerical model is presented for calculating the out-of-plane radiation loss in photonic-crystal slab waveguides. The propagation loss of a single-line defect waveguide in triangular-lattice photonic crystals is calculated for suspended-membrane, oxidized-lower- cladding, and deeply etched structures. The results show that low-loss waveguides are achievable for sufficiently suspended membranes and oxidized-lower- cladding structures. |
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| The Extent of DoD Influence on the Development and Application of Radio Frequency (RFID) Technology in the Civilian Sector |
JUN 2005 |
93 pages |
| Authors:
Rafael A. Acevedo; Robert W. Cooper; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| It would be a fair argument to say that there is perhaps no invention that has had as much impact on the world as that of the Internet. The internet, however, was conceived in the minds of government employees. Just as Government influenced the development of the internet, the same can be said of Radio Frequency Identification (RFID) Technology. The DoD had a very large impact on the development of ... |
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| Detection of Frequency-Hopped Signals Embedded in Interference Waveforms |
JUN 2005 |
57 pages |
| Authors:
Christopher Brown; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Many military communications systems utilize frequency-hopped spread spectrum waveforms to protect against jamming and enemy detection. These waveforms may be subjected not only to intentional jamming but may also be unintentionally jammed by other communications signals. While some systems can overcome inband interference with more signal power, covert systems may be limited to small amounts of transmitted power. The objective of this thesis was to investigate a method for resolving ... |
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| Closed Loop Control of a Cascaded Multi-Level Converter to Minimize Harmonic Distortion |
JUN 2005 |
105 pages |
| Authors:
Brian E. Souhan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| As the United States Navy moves toward the all-electric ship, the need for a robust, high fidelity inverter for propulsion motors becomes mandatory. Military vessels require high power converters capable of producing nearly sinusoidal outputs to prevent torque pulsations and electrical noise that can compromise the mission location. This thesis presents a hybrid pulse-width- modulated controller for a 3x3 Cascaded Multi-Level Converter (CMLC). Ancillary results include a simple technique for ... |
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| Modeling and Simulation of the Physical Layer of the Single Channel Ground and Airborne Radio System (SINCGARS) |
JUN 2005 |
75 pages |
| Authors:
Richard A. Paradise; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In this thesis, the physical layer of the Single Channel Ground and Airborne Radio System (SINCGARS) was analyzed to gain insight into the bit- error-rate (BER) performance in various channel conditions. The BER performance of the radio was examined using theoretical, simulation, and experimental techniques. These results are presented in graphical form as the probability of bit error as a function of the energy-per-bit to noise-power-spectral-density ratio. The results of ... |
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| Sea-Surface Specular Multipath for Surface-Level Antennas: Phase 1 |
JUN 2005 |
89 pages |
| Authors:
J. C. Allen; R. E. Goshorn; B. Zeidler; A. A. Beex; SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA
|
| This document describes a specular multipath simulation for antennas located close to a sea surface. The antennas are circularly polarized but the ray-trace implementation readily accommodates any other polarizations. The transmitted signal S(T)(t) arrives at the receiver's antenna along the direct path and from multiple reflections off the sea surface. The surface-level antenna turns the multipath into multiplicative noise-assuming the receiver is narrow band. Under this narrow-band assumption, the received ... |
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| Microwave Interferometry (90 GHz) for Hall Thruster Plume Density Characterization |
JUN 2005 |
7 pages |
| Authors:
Garrett D. Reed; William A. Hargus Jr.; Mark A. Cappelli; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
| A phase-bridge microwave interferometer operating at a frequency of 90 GHz (3mm wavelength) is currently under development at the Air Force Research Laboratory (AFRL) at Edwards AFB, California. The motivation for developing this diagnostic is the capability to take time resolved plasma density measurements with higher spatial resolution than other interferometers typically operating at 30 GHz. This interferometer has demonstrated preliminary electron density measurements in the plume of a 200 ... |
|
| Compilation of Theses Abstracts |
JUN 2005 |
141 pages |
| Authors:
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| It would be a fair argument to say that there is perhaps no invention that has had as much impact on the world as that of the Internet. The Internet, however, was conceived in the minds of government employees. Just as government influenced the development of the Internet, the same can be said of Radio Frequency Identification (RFID) Technology. The Department of Defense (DoD) had a very large impact on ... |
|
| Focused Ground-Penetrating Radar Backprojection Through a Lossy Interface |
JUN 2005 |
|
| Authors:
Elvis Dieguez; INSTITUTE FOR DEFENSE ANALYSES ALEXANDRIA VA
|
| We derive the propagation path at a lossless-lossy interface for use in backprojecting synthetic aperture radar (SAR) when used in ground-penetrating applications. To create a synthetic aperture radar (SAR) image using ground-penetrating radar (GPR) data, one must know the round-trip distance between the antenna aperture and the point to be focused on. Given a beginning point O in media II, a buried point P within media I, and the relationship ... |
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| Spatiotemporal Processing and Time-Reversal for Underwater Acoustic Communications |
JUN 2005 |
|
| Authors:
Daniel Y. Wang; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| High-rate underwater acoustic communication can be achieved using transmitter/receiver arrays. Underwater acoustic channels can be characterized as rapidly time-varying systems that suffer severe Inter Symbol Interferences (ISI) caused by multi-path propagation. Multi-channel combining and equalization, as well as time-reversal techniques have been used over these channels to reduce the effect of ISI. As an alternative, a spatiotemporal focusing technique had been proposed. This technique is similar to time-reversal but it ... |
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| Reflection of Microwave Pulses From Acoustic Waves: Summary of Experimental and Computational Studies |
31 MAY 2005 |
30 pages |
| Authors:
G. M. Kepler; R. A. Albanese; H. T. Banks; V. A. Bokil; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
|
| In [1, 4], the authors proposed and analyzed an interrogation (inverse problem) methodology based on use of an acoustic wave as a reflecting virtual interface for propagating impulses. It is by now well accepted (e.g., see [2, 7, 11, 14]) that acoustic pressure waves will interact with electromagnetic signals in ways that often mimic interfacial partial reflection/partial transmission for the electromagnetic waves. The response of atomic electrons to an applied ... |
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| Model-Data Comparisons of Shear Waves in the Nearshore |
27-May-2005 |
13 pages |
| Authors:
Steve Elgar; Falk Feddersen; T J Noyes; R T Guza; T H Herbers; SCRIPPS INST OF OCEANOGRAPHY LA JOLLA CA INTEGRATIVE OCEANOGRAPHY DIV
|
| Observations of shear waves, alongshore propagating meanders of the mean alongshore current with periods of a few minutes and alongshore wavelengths of a few hundred meters, are compared with model predictions based on numerical solutions of the nonlinear shallow water equations. The model assumes alongshore homogeneity and temporally steady wave forcing and neglects wave-current interactions, eddy mixing, and spatial variation of the (nonlinear) bottom drag coefficient. Although the shapes of ... |
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| Long-Range Fading Prediction and Realistic Physical Modeling to Enable Adaptive Transmission for Mobile Radio Networks |
18 MAY 2005 |
5 pages |
| Authors:
A. Duel-Hallen; H. Hallen; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| The feasibility of adaptive transmission enabled by Long Range Fading Prediction (LRP) was investigated for rapidly varying fading channels encountered in peer-to-peer mobile communication systems. The LRP algorithms were tested using the standard Jakes model and the realistic physical model developed by the Principal Investigators. This research was an interdisciplinary effort in communication theory, physics, and signal processing. Correlated fading was exploited in the development of the LRP algorithm to ... |
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| A Low-Power Remotely Readable Sensor |
18 MAY 2005 |
18 pages |
| Authors:
Donald H. Steinbrecher; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| A plurality of remotely readable sensor apparatus and reader systems for collecting data frames from all apparatus within the reader field of view. Each sensor apparatus converts one or more environmental observable into information signals, converts the information signals into digital data and appends other discriminating digital data as desired to form a digital data frame. The state of a diode, connected to an antenna with the digital data frame, ... |
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| Capon and Bartlett Beamforming: Threshold Effect in Direction-of-Arrival Estimation Error and On the Probability of Resolution |
16 MAY 2005 |
|
| Authors:
C. D. Richmond; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
| Below a specific threshold signal-to-noise ratio (SNR), the mean squared error (MSE) perfor- mance of signal direction-of arrival (DOA) estimates derived from the Capon algorithm degrades swiftly. Prediction of this threshold SNR point is of practical significance for robust system design and analysis. The exact pairwise error probabilities for the Capon (and Bartlett) algorithm are derived herein, given by simple finite sums involving no numerical integration, include finite sample effects, ... |
|
| Shark Attack Project - Marine Attack at Towed Hydrophone Arrays |
13 MAY 2005 |
3 pages |
| Authors:
Adrianus J. Kalmijn; CALIFORNIA UNIV REGENTS LA JOLLA CA SCRIPPS INST OF OCEANOGRAPHY
|
| The original objective of the SIO Marine Attack project was to identify the electric and magnetic fields causing sharks to inflict serious damage upon the towed hydrophone arrays of US Navy submarines. In contrast to the geophysical arrays that we studied concurrently, the US Navy's arrays appeared to be electromagnetically very quiet by proper design. The only galvanic fields we measured were those of some set screws of a dissimilar ... |
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| Novel THz-Frequency Spectrometers by Integrating Widely-Tunable Monochromatic THz Sources and Detectors, or Arrays of Emitters and Detectors, With Photonic Bandgap Crystals |
13 MAY 2005 |
7 pages |
| Authors:
Yuliya B. Zotova; ARKLIGHT CENTER VALLEY PA
|
| Within the last three months, we have investigated a 2-D photonic crystal embedded in a Si/SiO2/Si wafer. Such a study is essential for us to eventually implement an optimized photonic-crystal structure for splitting and combining the THz output and infrared pump beams. We have first optimized the design of our photonic crystal using the R-Soft software. We have then fabricated the photonic crystal. After that, we have tried to use ... |
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| Ultra-low Power Sentry for Ambient Powered Smart Sensors |
05 MAY 2005 |
33 pages |
| Authors:
Eric Moule; Mark Bocko; SIGNAL SCIENCES INC ROCHESTER NY
|
| The basic circuit operation of the power sentry system was presented previously in the 3rd Quarterly Report, but it has been updated and included again as a reminder. The proposed power sentry system requires several components to realize the signal processing technique for monitoring a sensor output to detect the presence of signals with defined frequency and amplitude properties. In this section, each component's role within the system will be ... |
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| A Study of Sub-MMW Systems and Component Requirements |
01 MAY 2005 |
30 pages |
| Authors:
H. B. Wallace; Mark Rosker; ORSA CORP ABERDEEN MD
|
| Three system concepts were identified that require a significant component development effort above 100 GHz -- 1) Look-down ISR into urban canyons, 2) All-weather obstacle avoidance, & 3) Concealed weapons detection. The program objective is to develope a sub-aperture transceiver to enable imaging at sub-MMW frequencies. Development of a single sub-aperture will allow forming arrays for each application |
|
| Polarimetric Backscattering Behavior of Ground Clutter at X, Ka, and W-band |
MAY 2005 |
13 pages |
| Authors:
A. J. Gatesman; T. M. Goyette; J. C. Dickinson; R. H. Giles; J. Waldman; J. Sizemore; R. M. Chase; W. E. Nixon; MASSACHUSETTS UNIV LOWELL SUBMILLIMETER-WAVE TECH LAB
|
| The HH and VV-polarized backscattering behavior of homogeneous ground clutter was investigated by measuring the radar cross section per unit area of rough surface terrain. The behavior of X, Ka, and W bands was investigated by analyzing ISAR imagery of 1/16th scale terrain collected in compact radar ranges operating at 160 GHz, 520 GHz, and 1.56 THz. An array of 27 ground planes was fabricated for the clutter study. Nine ... |
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| Exploitation of ISAR Imagery in Euler Parameter Space |
MAY 2005 |
13 pages |
| Authors:
Christopher Baird; W. T. Kersey; R. Giles; W. E. Nixon; MASSACHUSETTS UNIV LOWELL SUBMILLIMETER-WAVE TECH LAB
|
| Efforts are being made to exploit the full-polarimetric radar scattering nature of ground targets to extract maximum information, enabling target identification and classification. These efforts have taken varied approaches to decomposing the polarimetric scattering matrix into more meaningful, phenomenological parameter spaces. The Euler parameters have potential value in target classification but have historically met with limited success due to ambiguities that arise in decomposition as well as the parameters' sensitivity ... |
|
| Using Cramer-Rao Theory for SAR Waveform Design |
May-2005 |
6 pages |
| Authors:
Muralidhar Rangaswamy; Robert Linnehan; John Schindler; Leonid Perlovsky; David Brady; AIR FORCE RESEARCH LAB HANSCOM AFB MA
|
| This paper applies Cramer-Rao theory to synthetic aperture radar (SAR) in order to establish optimal performance bounds on target parameter estimation. The Cramer-Rao bound (CRB) establishes a lower bound on the error variance of unbiased or asymptotically efficient parameter estimates. Bounds on the estimation of various target parameters are developed, and the extension to multistatic SAR (MSAR) is considered. |
|
| Pre-Filtering for Clutter Rejection in Beamspace STAP |
May-2005 |
6 pages |
| Authors:
Michael C Wicks; Mehdi Khanpour-Ardestani; Raviraj S Adve; TORONTO UNIV (ONTARIO) DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Several space-time adaptive processing algorithms have been proposed to detect weak targets in the presence of strong interference, especially clutter and jamming. Except for Displaced Phase Center Array (DPCA) processing, radar signal processing algorithms ignore the fact that the location of the clutter ridge in angle-Doppler space is known, given the platform speed and direction. This paper introduces our attempt to exploit this a priori knowledge in conjunction with the ... |
|
| Code Inverse Filtering for Complete Sidelobe Removal in Binary Phase Coded Pulse Compression Systems |
May-2005 |
7 pages |
| Authors:
Robert C Daniels; Vilhelm Gregers-Hansen; NAVAL RESEARCH LAB WASHINGTON DC RADAR DIV
|
| Pulse compression is used in radar systems to improve range resolution while maintaining a high duty cycle. In addition to practical implementation constraints, the key issues for the selection of a pulse-compression waveform are mismatch loss, peak / integrated range sidelobes, and Doppler tolerance. While much progress has been made in the design of nonlinear frequency modulated (FM) chirp waveforms satisfying these requirements, the corresponding performance for binary phase-coded waveforms ... |
|
| Characterization of Nano-Scale Composites at THz and IR Spectral Region |
26 APR 2005 |
10 pages |
| Authors:
Haim Grebel; J. Federici; NEW JERSEY INST OF TECH NEWARK
|
| Characterizations of nanostructured carbon nanotube samples have been called out using Raman and THz spectroscopy. |
|
| Narrowband vs. Wideband Radar Experiment: Precursor Data Acquisition |
15 APR 2005 |
4 pages |
| Authors:
Timothy E. Olson; Colby Dill III; VALHALLA TECHNOLOGIES LLC DELAND FL
|
| Design of a narrowband vs. wideband experiment was conducted as proposed. The system was operationally tested and a great deal of data was gathered and provided to the Air Force. This data suggests the future viability of such a wideband system. We also proposed the future testing protocol, by which the project can be brought to a higher level and hopefully transitioned into production. |
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| HF Surface Wave Radar Operation in Adverse Conditions |
14 APR 2005 |
7 pages |
| Authors:
Anthony M. Ponsford; Reza M. Dizaji; Richard McKerracher; RAYTHEON CANADA LTD WATERLOO (ONTARIO)
|
| For the past 12 years the Canadian Department of National Defense and Raytheon Canada Limited have collaborated on a cost-shared programme to develop an Integrated Maritime Surveillance (IMS) system based on HF Surface Wave Radar (HFSWR). the primary objective behind the programme was to demonstrate the capability of HFSWR to continuously detect and track surface targets (ships and icebergs) as well as airborne targets, at all altitudes, to ranges in ... |
|
| Compression Ratio Expansion for Complementary Code Set Compressing a Signal to a Width of Several Sub-pulses |
14 APR 2005 |
5 pages |
| Authors:
Reiji Sato; Masanori Shinriki; Hiroshi Takase; JAPAN DEFENCE AGENCY TOKYO
|
| We present the compression ratio expansion methods for the complementary code set compressing a signal to a width of several sub-pulses. We also propose the complementary code sets that consist of more that three individual codes and compress a signal to a width of several sub-pulses. |
|
| Limits to the Extraction of Information from Multi-Hop Skywave Radar Signals |
14 APR 2005 |
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| Authors:
Stuart Anderson; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION SALISBURY (AUSTRALIA)
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| The performance of high-frequency skywave radar systems is customarily referred to in terms of single-hop propagations, a mechanism which provides illumination of the earth's surface out to ranges of around 4000 kilometers. In practice, the process of ionospheric reflection often supports multiple hops, though the signals are inevitably subjected to much greater distortion and contamination. In this paper, the author addresses the issue of adequacy of conventional models of multi-hop ... |
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| Probing of the Artificial Hole in the Ionosphere with the HF Skywave Radar |
14 APR 2005 |
6 pages |
| Authors:
Pei-Nan Jiao; Tie-Han Ma; Guo-Liang Xu; Zong-Qiang Li; Xin-Sheng Zhang; Fei Xu; CHINA RESEARCH INST OF RADIOWAVE PROPAGATION XINXIANG (CHINA)
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| This paper describes an experiment in which high-frequency sky wave radar probed the artificial ionospheric hole that was caused by the flames of a rocket that was vertically launched and that penetrated the ionosphere. After the rocket had passed through the ionosphere the minimum time delay P(sub min)-f on the backscatter ionograms showed wave and focusing stripes resulting from the irregular structure. The results indicated a low electron density zone ... |
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Radiofrequency Wave Propagation
