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OEP terminal and CONUS weather radar coverage gap identification analysis for NextGen

Author:
Published in:
MIT Lincoln Laboratory Report ATC-369

Summary

The initial results of a weather radar coverage analysis in support of the Reduce Weather Impacts (RWI) Sensor RightSizing program are presented. The main impetus behind this study is to identify gaps in the radar network relative to the Next Generation Air Transportation System (NextGen) end-state performance requirements. Because detailed performance requirements are currently available only for super-density terminal airspace, we focused on this domain. We also analyzed, to a lesser extent, the contiguous United States (CONUS) airspace as an approximation to the en route airspace. Significant gaps were uncovered in the following requirement areas. (1) Vertical resolution. The current weather radar network (and any future radar network of reasonable cost) will not meet the 4D weather cube single authoritative source (4D WxSAS) vertical resolution requirements for both super-density terminal and en route airspace domains. (2) Vertical accuracy. Accurate determination of the radar beam height is difficult due to the natural variability of the vertical refractivitiy gradient in the atmosphere. (3) Update period for convective weather. The current weather radars have volume scan update periods that are substantially longer than the required times. (4) Horizontal resolution. This requirement is met in only some parts of the super-density terminal and en route airspaces (5) Low-altitude coverage. The current weather radars are generally spaced too far apart to provide seamless coverage of the boundary layer. (6) Overall terminal airspace weather radar coverage is significantly diminished due to terrain blockage at a handful of major airports.
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Summary

The initial results of a weather radar coverage analysis in support of the Reduce Weather Impacts (RWI) Sensor RightSizing program are presented. The main impetus behind this study is to identify gaps in the radar network relative to the Next Generation Air Transportation System (NextGen) end-state performance requirements. Because detailed...

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Advanced packaging of high-power slab-coupled optical waveguide laser and amplifier arrays for coherent beam combining

Summary

Individually addressable GaAs-based 9XX-nm Slab-Coupled Optical Waveguide (SCOW) laser and amplifier arrays have been demonstrated in a modular 2-D stacked architecture. Approximately 20 W of coherently-combined power was obtained from two optically stacked amplifier modules.
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Summary

Individually addressable GaAs-based 9XX-nm Slab-Coupled Optical Waveguide (SCOW) laser and amplifier arrays have been demonstrated in a modular 2-D stacked architecture. Approximately 20 W of coherently-combined power was obtained from two optically stacked amplifier modules.

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Multifunction phased array radar (MPAR) for aircraft and weather surveillance

Summary

MIT Lincoln Laboratory and M/A-COM are jointly conducting a technology demonstration of affordable Multifunction Phased Array Radar (MPAR) technology for Next Generation air traffic control and national weather surveillance services. Aggressive cost and performance goals have been established for the system. The array architecture and its realization using custom Transmit and Receive Integrated Circuits and a panel-based Line Replaceable Unit (LRU) will be presented. A program plan for risk reduction and system demonstration will be outlined.
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Summary

MIT Lincoln Laboratory and M/A-COM are jointly conducting a technology demonstration of affordable Multifunction Phased Array Radar (MPAR) technology for Next Generation air traffic control and national weather surveillance services. Aggressive cost and performance goals have been established for the system. The array architecture and its realization using custom Transmit...

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Terminal Doppler Weather Radar enhancements

Author:
Published in:
IEEE Radar Conf., 10 May 2010, pp. 1245-1249.

Summary

The design of an open radar data acquisition system for the Terminal Doppler Weather Radar is presented. Adaptive signal transmission and processing techniques that take advantage of the enhanced capabilities of this new system are also discussed. Results displaying data quality improvements with respect to problems such as range-velocity ambiguity and moving clutter are shown.
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Summary

The design of an open radar data acquisition system for the Terminal Doppler Weather Radar is presented. Adaptive signal transmission and processing techniques that take advantage of the enhanced capabilities of this new system are also discussed. Results displaying data quality improvements with respect to problems such as range-velocity ambiguity...

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Improvement of SOI MOSFET RF performance by implant optimization

Published in:
IEEE Microw. Wirel. Compon. Lett., Vol. 20, No. 5, May 2010, pp. 271-273.

Summary

The characteristics of silicon on insulator MOSFETs are modified to enhance the RF performance by varying channel implants. Without adding new masks or fabrication steps to the standard CMOS process, this approach can be easily applied in standard foundry fabrication. The transconductance, output resistance, and breakdown voltage can be increased by eliminating channel and drain extension implants. As a result, the fmax of the modified n-MOSFET with a 150 nm gate length exceeds 120 GHz, showing a 20% improvement over the standard MOSFET for digital circuits on the same wafer.
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Summary

The characteristics of silicon on insulator MOSFETs are modified to enhance the RF performance by varying channel implants. Without adding new masks or fabrication steps to the standard CMOS process, this approach can be easily applied in standard foundry fabrication. The transconductance, output resistance, and breakdown voltage can be increased...

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CIWS product description, revision 1.0

Author:
Published in:
MIT Lincoln Laboratory Report ATC-355

Summary

Lincoln Laboratory has developed a set of information models for the encoding and distribution of data products from the National Corridor Integrated Weather System (CIWS) prototype, currently operating at Lincoln Laboratory in Lexington, Massachusetts. CIWS data products can be categorized as gridded and non-gridded. Gridded products are typically expressed as rectangular arrays whose elements contain a data value coinciding with uniformly-spaced observations or computed results on a 2-D surface. Gridded data arrays map to earth's surface through a map projection, for example, Lambert Conformal or Lambert Azimuthal Equal-Area. Non-gridded data products express observations or computed results associated with singular or sparsely distributed sets of geo-spatial locations such as points, curves, or contours. CIWS prototype data products were used to develop, refine, and evaluate reference information models for the CIWS gridded and non-gridded data. Data packaging methods were evaluated and selected on the basis of public-domain open-source availability and metadata support. Network Common Data Format (NetCDF), provided by Unidata, was selected as the information model for gridded CIWS products. For the non-gridded products, XML schemas have been developed along with sample XML instances to illustrate schema-compliant product encodings. These models follow and extend upon a number of Open Geospatial Consortium (OGC) and ISO standards including Geography Markup Language (GML), Observations and Measurements (OM), and Eurocontrol's Weather Exchange Model (WXXM). This document is intended to serve as a reference for the description of CIWS data product files.
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Summary

Lincoln Laboratory has developed a set of information models for the encoding and distribution of data products from the National Corridor Integrated Weather System (CIWS) prototype, currently operating at Lincoln Laboratory in Lexington, Massachusetts. CIWS data products can be categorized as gridded and non-gridded. Gridded products are typically expressed as...

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Signal processing algorithms for the Terminal Doppler Weather Radar: Build 2

Author:
Published in:
MIT Lincoln Laboratory Report ATC-363

Summary

As a new radar data acquisition system (RDA) was developed for the Terminal Doppler Weather Radar (TDWR), enhanced signal processing algorithms taking advantage of its increased capabilities were also developed. The primary goals of protecting the base data estimates from range-aliased signals and providing reliable velocity dealiasing were achieved through multiple pulse repetition interval (PRI) and phase coding methods. An innovative radial-by-radial adaptive selection process was used to take full advantage of the different techniques, the first time such an approach has been implemented for weather radars. Improvement in clutter filtering was also achieved. This report discusses in detail these new RDA signal processing algorithms.
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Summary

As a new radar data acquisition system (RDA) was developed for the Terminal Doppler Weather Radar (TDWR), enhanced signal processing algorithms taking advantage of its increased capabilities were also developed. The primary goals of protecting the base data estimates from range-aliased signals and providing reliable velocity dealiasing were achieved through...

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The application of statistical relational learning to a database of criminal and terrorist activity

Published in:
SIAM Conf. on Data Mining, 29 April - 1 May 2010.

Summary

We apply statistical relational learning to a database of criminal and terrorist activity to predict attributes and event outcomes. The database stems from a collection of news articles and court records which are carefully annotated with a variety of variables, including categorical and continuous fields. Manual analysis of this data can help inform decision makers seeking to curb violent activity within a region. We use this data to build relational models from historical data to predict attributes of groups, individuals, or events. Our first example involves predicting social network roles within a group under a variety of different data conditions. Collective classification can be used to boost the accuracy under data poor conditions. Additionally, we were able to predict the outcome of hostage negotiations using models trained on previous kidnapping events. The overall framework and techniques described here are flexible enough to be used to predict a variety of variables. Such predictions could be used as input to a more complex system to recognize intent of terrorist groups or as input to inform human decision makers.
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Summary

We apply statistical relational learning to a database of criminal and terrorist activity to predict attributes and event outcomes. The database stems from a collection of news articles and court records which are carefully annotated with a variety of variables, including categorical and continuous fields. Manual analysis of this data...

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Data diodes in support of trustworthy cyber infrastructure

Published in:
6th Annual Cyber Security and Information Intelligence Research Workshop, Cyber Security and Information Intelligence Challenges and Strategies, CSIIRW10, 21 April 2010.

Summary

Interconnections between process control networks and enterprise networks has resulted in the proliferation of standard communication protocols in industrial control systems which exposes instrumentation, control systems, and the critical infrastructure components they operate to a variety of cyber attacks. Various standards and technologies have been proposed to protect industrial control systems against cyber attacks and to provide them with confidentiality, integrity, and availability. Among these technologies, data diodes provide protection of critical systems by the means of physically enforcing traffic direction on the network. In order to deploy data diodes effectively, it is imperative to understand the protection they provide, the protection they do not provide, their limitations, and their place in the larger security infrastructure. In this work, we briefly review the security challenges in an industrial control system, study data diodes, their functionalities and limitations, and propose a scheme for their effective deployment in trusted process control networks (TPCNs.)
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Summary

Interconnections between process control networks and enterprise networks has resulted in the proliferation of standard communication protocols in industrial control systems which exposes instrumentation, control systems, and the critical infrastructure components they operate to a variety of cyber attacks. Various standards and technologies have been proposed to protect industrial control...

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Improved Monte Carlo sampling for conflict probability estimation

Published in:
51st AIAA/ASME/AHS/ACS Structures, Structural Dynamics, and Materials Conf., 12-15 April 2010.

Summary

Probabilistic alerting systems for airborne collision avoidance often depend upon accurate estimates of the probability of conflict. Analytical, numerical approximation, and Monte Carlo methods have been applied to conflict probability estimation. The advantage of a Monte Carlo approach is the greater flexibility afforded in modeling the stochastic behavior of aircraft encounters, but typically many samples are required to provide an adequate conflict probability estimate. One approach to improve accuracy with fewer samples is to use importance sampling, where trajectories are sampled according to a proposal distribution that is different from the one specified by the model. This paper suggests several different sample proposal distributions and demonstrates how they result in significantly improved estimates.
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Summary

Probabilistic alerting systems for airborne collision avoidance often depend upon accurate estimates of the probability of conflict. Analytical, numerical approximation, and Monte Carlo methods have been applied to conflict probability estimation. The advantage of a Monte Carlo approach is the greater flexibility afforded in modeling the stochastic behavior of aircraft...

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