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Dwell scheduling algorithms for phased array antenna

January 1, 2013
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Journal Article
Author:
Zoran Spasojevic
…
Published in:
IEEE Trans. Aerosp. Electron. Syst., Vol. 49, No. 1, January 2013, pp. 42-54.
Topic:
radar
R&D area:
R&D group:

Summary

In a multifunctional radar performing searching and tracking operations, the maximum number of targets that can be managed is an important measure of performance. One way a radar can maximize tracking performance is to optimize its dwell scheduling. The problem of designing efficient dwell scheduling algorithms for various tracking and searching scenarios with respect to various objective functions has been considered many times in the past and many solutions have been proposed. We consider the dwell scheduling problem for two different scenarios where the only objective is to maximize the number of dwells scheduled during a scheduling period. We formulate the problem as a distributed and a nondistributed bin packing problem and present optimal solutions using an integer programming formulation. Obtaining an optimal solution gives the limit of radar performance. We also present a more computationally friendly but less optimal solution using a greedy approach.
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Summary

In a multifunctional radar performing searching and tracking operations, the maximum number of targets that can be managed is an important measure of performance. One way a radar can maximize tracking performance is to optimize its dwell scheduling. The problem of designing efficient dwell scheduling algorithms for various tracking and...

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Dwell scheduling algorithms for phased array antenna

Multifunction Phased Array Radar wind shear experiment

November 5, 2012
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Conference Paper
Author:
Pamela L. Heinselman
…
Published in:
26th Conf. on Sever Local Storms, 5-8 November 2012.
Topic:
algorithms
R&D area:
R&D group:

Summary

Terminal Doppler Weather Radars (TDWRs) provide near-ground wind shear detection that is critical for aircraft safety at 46 airports across the United States. These systems are part of the larger network of 510 weather and aircraft surveillance radars owned and operated by government agencies in the continental United States. As the TDWR and other radar systems approach their engineering design life cycles, the Federal Aviation Administration (FAA), National Weather Service (NWS), and Department of Defense (DoD) are considering potential replacement systems (OFCM 2006; Weber et al. 2007). One option under consideration that would maintain the current airspace coverage is a replacement network of 334 Multifunction Phased Array Radars (MPARs) (Weber et al. 2007). The MPAR network described by Weber et al. (2007) would include two classes of systems: A high-resolution, full-scale version with an 8-m diameter antenna, and a lower-resolution terminal version with a 4-m diameter antenna, termed Terminal MPAR, or TMPAR. As the proposed TMPAR design has lower azimuthal beam resolution and less sensitivity than TDWRs, it is crucial to determine the impacts of that design on the detection of low-altitude wind shear. The design of the SPY-1A PAR, a research radar at the National Weather Radar Test Bed in Norman, Oklahoma (Zrnić et al. 2007), makes it a good proxy for examining the potential wind shear detection performance of the TMPAR. Therefore, in spring 2012, the National Oceanic and Atmospheric Administration (NOAA) National Severe Storms Laboratory organized and executed the MPAR Wind Shear Experiment (WSE) in collaboration with the FAA, NOAA's NWS Radar Operations Center, the University of Oklahoma Advanced Radar Research Center (OU ARRC), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). The primary objective of the MPAR WSE was to collect low-altitude observations with the SPY-1A PAR (hereafter, PAR) for comparison with observations from the nearby Oklahoma City (OKC) TDWR. Of particular interest is comparison of MIT LL wind shear detection algorithm performance using data from these two radars; this analysis is reported in Cho et al. (2013). Data were also collected from other radars in central Oklahoma to facilitate basic research on microbursts and other wind-producing storms. This paper provides an overview of the MPAR WSE and observed wind shear events.
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Summary

Terminal Doppler Weather Radars (TDWRs) provide near-ground wind shear detection that is critical for aircraft safety at 46 airports across the United States. These systems are part of the larger network of 510 weather and aircraft surveillance radars owned and operated by government agencies in the continental United States. As...

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Multifunction Phased Array Radar wind shear experiment

Towards the detection of aircraft icing conditions using operational dual-polarimetric radar

June 25, 2012
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Conference Paper
Author:
Scott Ellis
…
Published in:
7th European Conf. on Radar in Meteorology and Hydrology, ERAD, 25-29 June 2012.
Topic:
algorithms
R&D area:
R&D group:

Summary

In anticipation of the dual-polarimetric upgrade to the National Weather Service operational radar network (WSR-88D) research is being conducted to utilize this extensive new data source for remote aircraft icing detection. The first challenge is to accurately locate the melting layer. A new image-processing-based algorithm is proposed and demonstrated. The next challenge is to use the dual-polarimetric data above the melting level to distinguish regions containing super-cooled liquid water, which constitutes an aviation icing hazard, from regions of pure ice and snow. It has been well documented that the S-band dual-polarimetric radar signatures at individual range gates of super-cooled liquid water and ice crystals overlap significantly, complicating the identification of icing conditions using individual radar measurements. Recently several investigators have found that the aggregate characteristics of dual-polarimetric radar measurements over regions on the order of several kilometers show distinguishing features between regions containing super-cooled liquid and those with ice only. In this study, the features found in the literature are evaluated, extended and combined using a fuzzy-logic framework to provide an icing threat likelihood. The results of this new algorithm are computed using data collected in Colorado from the Colorado State University CHILL radar and the National Center for Atmospheric Research S-Pol radar (collectively called FRONT – The Front Range Observational Testbed) collected in the winter of 2010/2011 in coordination with the NASA Icing Remote Sensing System (NIRSS) and compared to pilot reports on approach or departure from nearby airports. The preliminary results look encouraging and will be presented. The ultimate goal is to produce an end-to-end algorithm to produce a reliable icing threat product that can then be combined with existing icing detection systems to improve their performance.
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Summary

In anticipation of the dual-polarimetric upgrade to the National Weather Service operational radar network (WSR-88D) research is being conducted to utilize this extensive new data source for remote aircraft icing detection. The first challenge is to accurately locate the melting layer. A new image-processing-based algorithm is proposed and demonstrated. The...

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Towards the detection of aircraft icing conditions using operational dual-polarimetric radar

A knowledge-based operator for a genetic algorithm which optimizes the distribution of sparse matrix data

January 1, 2012
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Book Chapter
Author:
Una-May O'Reilly
…
Published in:
Parallel Architectures and Bioinspired Algorithms
Topic:
algorithms
R&D area:
R&D group:

Summary

We present the Hogs and Slackers genetic algorithm (GA) which addresses the problem of improving the parallelization efficiency of sparse matrix computations by optimally distributing blocks of matrices data. The performance of a distribution is sensitive to the non-zero patterns in the data, the algorithm, and the hardware architecture. In a candidate distributions the Hogs and Slackers GA identifies processors with many operations – hogs, and processors with fewer operations – slackers. Its intelligent operation-balancing mutation operator then swaps data blocks between hogs and slackers to explore a new data distribution.We show that the Hogs and Slackers GA performs better than a baseline GA. We demonstrate Hogs and Slackers GA’s optimization capability with an architecture study of varied network and memory bandwidth and latency.
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Summary

We present the Hogs and Slackers genetic algorithm (GA) which addresses the problem of improving the parallelization efficiency of sparse matrix computations by optimally distributing blocks of matrices data. The performance of a distribution is sensitive to the non-zero patterns in the data, the algorithm, and the hardware architecture. In...

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A knowledge-based operator for a genetic algorithm which optimizes the distribution of sparse matrix data

Linear algebraic notation and definitions

January 1, 2012
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Book Chapter
Author:
Eric I. Robinson
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Published in:
Graph Algorithms in the Language of Linear Algebra, pp. 13-18.
Topic:
algorithms
R&D area:
R&D group:

Summary

This chapter presents notation, definitions, and conventions for graphs, matrices, arrays, and operations upon them.
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Summary

This chapter presents notation, definitions, and conventions for graphs, matrices, arrays, and operations upon them.

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Linear algebraic notation and definitions

Graphs and matrices

January 1, 2012
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Book Chapter
Author:
Jeremy Kepner
Published in:
Graph Algorithms in the Language of Linear Algebra, pp. 3-12
Topic:
algorithms
R&D area:
R&D group:

Summary

A linear algebraic approach to graph algorithms that exploits the sparse adjacency matrix representation of graphs can provide a variety of benefits. These benefits include syntactic simplicity, easier implementation, and higher performance. Selected examples are presented illustrating these benefits. These examples are drawn from the remainder of the book in the areas of algorithms, data analysis, and computation.
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Summary

A linear algebraic approach to graph algorithms that exploits the sparse adjacency matrix representation of graphs can provide a variety of benefits. These benefits include syntactic simplicity, easier implementation, and higher performance. Selected examples are presented illustrating these benefits. These examples are drawn from the remainder of the book in...

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Graphs and matrices

Hogs and slackers: using operations balance in a genetic algorithm to optimize sparse algebra computation on distributed architectures

October 1, 2010
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Journal Article
Author:
Una-May O'Reilly
…
Published in:
Parallel Comput., Vol. 36, No. 10-11, October-November 2010, pp. 635-644.
Topic:
algorithms
R&D area:
R&D group:

Summary

We present a framework for optimizing the distributed performance of sparse matrix computations. These computations are optimally parallelized by distributing their operations across processors in a subtly uneven balance. Because the optimal balance point depends on the non-zero patterns in the data, the algorithm, and the underlying hardware architecture, it is difficult to determine. The Hogs and Slackers genetic algorithm (GA) identifies processors with many operations - hogs, and processors with few operations - slackers. Its intelligent operation-balancing mutation operator swaps data blocks between hogs and slackers to explore new balance points. We show that this operator is integral to the performance of the genetic algorithm and use the framework to conduct an architecture study that varies network specifications. The Hogs and Slackers GA is itself a parallel algorithm with near linear speedup on a large computing cluster.
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Summary

We present a framework for optimizing the distributed performance of sparse matrix computations. These computations are optimally parallelized by distributing their operations across processors in a subtly uneven balance. Because the optimal balance point depends on the non-zero patterns in the data, the algorithm, and the underlying hardware architecture, it...

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Hogs and slackers: using operations balance in a genetic algorithm to optimize sparse algebra computation on distributed architectures

An algorithm to identify robust convective weather avoidance polygons in en route airspace

September 13, 2010
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Conference Paper
Author:
Mikhail Rubnich
…
Published in:
ATIO 2010: 10th AIAA Aviation Technology Integration and Operations Conf., 13-15 September 2010.
Topic:
weather
R&D area:
R&D group:

Summary

The paper describes an algorithm for constructing convective weather avoidance polygons. The algorithm combines weather avoidance fields (WAF) from the en route convective weather avoidance model (CWAM) with edges automatically detected in the echo tops field, clustering, convex hull fitting and wind data to build weather avoidance polygons. Results for 2 case days with significantly different weather patterns were classified and studied.
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Summary

The paper describes an algorithm for constructing convective weather avoidance polygons. The algorithm combines weather avoidance fields (WAF) from the en route convective weather avoidance model (CWAM) with edges automatically detected in the echo tops field, clustering, convex hull fitting and wind data to build weather avoidance polygons. Results for...

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An algorithm to identify robust convective weather avoidance polygons in en route airspace

Collision avoidance for unmanned aircraft using Markov Decision Processes

August 2, 2010
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Conference Paper
Author:
Selim Temizer
…
Published in:
AIAA Guidance, Navigation, and Control Conf., 2-5 August 2010.
Topic:
collision avoidance
R&D area:
R&D group:

Summary

Before unmanned aircraft can fly safely in civil airspace, robust airborne collision avoidance systems must be developed. Instead of hand-crafting a collision avoidance algorithm for every combination of sensor and aircraft configuration, we investigate the automatic generation of collision avoidance algorithms given models of aircraft dynamics, sensor performance, and intruder behavior. By formulating the problem of collision avoidance as a Markov Decision Process (MDP) for sensors that provide precise localization of the intruder aircraft, or a Partially Observable Markov Decision Process (POMDP) for sensors that have positional uncertainty or limited field-of-view constraints, generic MDP/POMDP solvers can be used to generate avoidance strategies that optimize a cost function that balances flight-plan deviation with collision. Experimental results demonstrate the suitability of such an approach using four different sensor modalities and a parametric aircraft performance model.
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Summary

Before unmanned aircraft can fly safely in civil airspace, robust airborne collision avoidance systems must be developed. Instead of hand-crafting a collision avoidance algorithm for every combination of sensor and aircraft configuration, we investigate the automatic generation of collision avoidance algorithms given models of aircraft dynamics, sensor performance, and intruder...

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Collision avoidance for unmanned aircraft using Markov Decision Processes

Terminal Doppler Weather Radar enhancements

May 10, 2010
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Conference Paper
Author:
John Y. Cho
…
Published in:
IEEE Radar Conf., 10 May 2010, pp. 1245-1249.
Topic:
algorithms
R&D area:
R&D group:

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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Terminal Doppler Weather Radar enhancements
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