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Wind-shear detection performance study for multifunction phased array radar (MPAR) risk reduction
June 12, 2013
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-409
Summary
Multifunction phased array radars (MPARs) of the future that may replace the current terminal wind-shear detection systems will need to meet the Federal Aviation Administration's (FAA) detection requirements. Detection performance issues related to on-airport siting of MPAR, its broader antenna beamwidth relative to the TDWR, and the change in operational frequency from C band to S band are analyzed. Results from the 2012 MPAR Wind-Shear Experiment (WSE) are presented, with microburst and gust-front detection statistics for the Oklahoma City TDWR and the National Weather Radar Testbed (NWRT) phased array radar, which are located 6 km apart. The NWRT has sensitivity and beamwidth similar to a conceptual terminal MPAR (TMPAR), which is a scaled-down version of a full-size MPAR. The microburst results show both the TDWR probability of detection (POD) and the estimated NWRT POD exceeding the 90% requirement. For gust fronts, however, the overall estimated NWRT POD was more than 10% lower than the TDWR POD. NWRT data is also used to demonstrate that rapid-scan phased array radar has the potential to enhance microburst prediction capability.
Summary
Multifunction phased array radars (MPARs) of the future that may replace the current terminal wind-shear detection systems will need to meet the Federal Aviation Administration's (FAA) detection requirements. Detection performance issues related to on-airport siting of MPAR, its broader antenna beamwidth relative to the TDWR, and the change in operational...
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Dwell scheduling algorithms for phased array antenna
January 1, 2013
Journal Article
Published in:
IEEE Trans. Aerosp. Electron. Syst., Vol. 49, No. 1, January 2013, pp. 42-54.
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.
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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Multifunction phased array radar (MPAR) spectral usage analysis
July 24, 2012
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-395
Topic:
R&D area:
Summary
This report addressed two technical risks associated with replacing current air traffic and weather surveillance radars with a single type of multifunction phased array radar (MPAR). The first risk is whether radio spectrum usage would increase with the MPAR network and whether the allocated band will have enough spectral space. This question is addressed in two steps. First, single-radar spectrum usage is estimated based on certain assumptions regarding the radar design. Second, locations based on a previous radar placement study are used together with a terrain-dependent propagation model to compute the number of frequency channels needed at each site. We conclude that the overall spectrum usage is likely to increase with MPAR, but that the targeted window in S band will be able to accommodate the occupancy at all sites. The second risk is whether self-interference will limit the ability of the MPAR to operate asynchronously and adaptively on different antenna faces. This question is addressed by employing a simple bistatic ground clutter model to characterize the interference between adjacent faces. We conclude that some interference is unavoidable, but it would likely only occur during times when a transmit beam is at its maximum off-broadside angle (~2% of the time).
Summary
This report addressed two technical risks associated with replacing current air traffic and weather surveillance radars with a single type of multifunction phased array radar (MPAR). The first risk is whether radio spectrum usage would increase with the MPAR network and whether the allocated band will have enough spectral space...
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Towards the detection of aircraft icing conditions using operational dual-polarimetric radar
June 25, 2012
Conference Paper
Published in:
7th European Conf. on Radar in Meteorology and Hydrology, ERAD, 25-29 June 2012.
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.
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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NextGen surveillance and weather radar capability (NSWRC) siting analysis
May 22, 2012
Project Report
Published in:
Project Report ATC-391, MIT Lincoln Laboratory
Summary
As the current radars that perform weather and aircraft surveillance over the United States age, they must be sustained through service life extension programs or replaced. In the latter case, the radars can be replaced by multiple types of radars with different missions or they can be replaced by scalable multifunction phased array radars (MPARs). State-of-the-art active phased array systems have the potential to provide improved capabilities such as earlier detection and better characterization of hazardous weather phenomena, 3D tracking of noncooperative aircraft, better avoidance of unwanted clutter sources such as wind farms, and more graceful performance degradation with component failure. As the U.S. aviation community works toward realizing the Next Generation Air Transportation System (NextGen), achieving improved capabilities for aircraft and weather surveillance becomes critical, because stricter observation requirements are believed to be needed. Hence, the Federal Aviation Administration (FAA) is considering the MPAR as a possible solution to their NextGen Surveillance and Weather Radar Capability (NSWRC). Cost is one hurdle to the deployment of a modern phased array radar network. One way of lowering the overall cost is to reduce the total number of radars. Because of the overlap in coverage provided by the current radar networks, a unified MPAR replacement network can potentially decrease the total number of radars needed to cover the same airspace. An earlier analysis conducted by MIT Lincoln Laboratory concluded that 510 legacy radars could be effectively replaced by 334 MPARs over the contiguous United States (CONUS). There was, however, some uncertainty whether the spatial resolution used in the terrain blockage calculations was fine enough to accurately depict radar coverage, and also if terminal area coverage was being adequately addressed. This study revisits the siting analysis using a much finer spatial resolution, expands the coverage domain to include all fifty states and U.S. territories, adds the Air Force long-range surveillance radars (FPSs) to the legacy pool, and allows scaling by number of faces per radar. The aim is to provide an estimate of the minimum number of MPARs needed to replace the existing radar coverage. We also provide an extensive statistical compilation of legacy versus MPAR coverage for various observational performance parameters.
Summary
As the current radars that perform weather and aircraft surveillance over the United States age, they must be sustained through service life extension programs or replaced. In the latter case, the radars can be replaced by multiple types of radars with different missions or they can be replaced by scalable...
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Dual polarization radar winter storm studies supporting development of NEXRAD-based aviation hazard products
September 29, 2011
Conference Paper
Published in:
35th Conf. on Radar Meteorology, 26-30 September 2011.
Summary
The Next Generation Weather Radar (NEXRAD) dual polarization upgrade has begun adding a functional enhancement to classify hydrometeors. MIT Lincoln Laboratory (LL) develops NEXRAD-based weather radar products for Federal Aviation Administration (FAA) weather systems such as Corridor Integrated Weather System (CIWS), Integrated Terminal Weather System (ITWS), and Weather and Radar Processor (WARP). Without dual polarization, those products are limited to providing information on precipitation location and intensity. With dual polarization, LL is now developing new aviation weather products to determine locations of hydrometeor-based hazards. A product for Icing Hazards Level (IHL) is expected to benefit the FAA. LL has partnered with Valparaiso University (VU) in northern Indiana near Chicago since 2008 to study the evolution of winter storms prior to the NEXRAD dual polarization upgrade. VU contributes to the study a C-band dual polarization weather radar, an on-demand local sounding capability, and a surface winter weather verification team. Additionally, the Wolcott, IN wind profiler is about 70 km south within viewing range of the VU radar, and provides information on the fall speeds of the hydrometeors of interest. This resource-rich location has allowed for substantive study of many winter storm types: synoptic, lake effect, and frontal passages. A key to development of the IHL product is the ability to interpret dual polarization radar signatures from the winter microphysical states and precipitation structures. Evolution of the structures is a response to the microphysical water and ice saturation (sub or super) states. The magnitude of the vertical lift may affect the saturation states. Methods to segregate the radar signatures will be important regarding the inferred presence of a supercooled water icing hazard. The blizzard of Feb. 1 and 2, 2011 produced four distinct precipitation periods (snow, sleet, freezing drizzle, and lake effect snow), all of which will be discussed. The paper and presentation will also detail findings from the study of multiple winter storms and how they inform the development of the IHL product.
Summary
The Next Generation Weather Radar (NEXRAD) dual polarization upgrade has begun adding a functional enhancement to classify hydrometeors. MIT Lincoln Laboratory (LL) develops NEXRAD-based weather radar products for Federal Aviation Administration (FAA) weather systems such as Corridor Integrated Weather System (CIWS), Integrated Terminal Weather System (ITWS), and Weather and Radar...
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Overlapped digital subarray architecture for multiple beam phased array radar
April 11, 2011
Conference Paper
Published in:
EuCAP 2011, 5th European Conf. on Antrennas and Propagation, 11-15 April 2011, pp. 3027-3030.
Summary
MIT Lincoln Laboratory is 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 panel-based Line Replaceable Unit (LRU) will be presented. A program plan for risk reduction and system demonstration will be outlined.
Summary
MIT Lincoln Laboratory is 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...
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Analysis of ground-based radar low-altitude wind-shear detection in OEP terminal airspace for NextGen
December 2, 2010
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-375
Summary
To support the Next Generation Air Transportation System (NextGen), the Reduce Weather Impact Sensor RightSizing program is identifying and analyzing gaps in the current sensor network coverage relative to the Four-Dimensional Weather Data Cube Single Authoritative Source performance requirements. In this study, we look for shortfalls in low-altitude wind-shear sensing by ground-based radars and lidar in the NextGen super-density operations (SDO) terminal airspace. Specifically, 2D gridded wind-shear visibility (an upper bound to detection probability) data are generated for microbursts and gust fronts separately for different sensors, namely the Terminal Doppler Weather Radar, Next Generation Weather Radar, Airport Surveillance Radar-9 with Weather Systems Processor, and Doppler lidar.
Summary
To support the Next Generation Air Transportation System (NextGen), the Reduce Weather Impact Sensor RightSizing program is identifying and analyzing gaps in the current sensor network coverage relative to the Four-Dimensional Weather Data Cube Single Authoritative Source performance requirements. In this study, we look for shortfalls in low-altitude wind-shear sensing...
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Low cost multifunction phased array radar concept
October 12, 2010
Conference Paper
Published in:
2010 IEEE Int. Symp. on Phased Array Systems, 12 October 2010.
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.
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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Results of X-band electronically scanned array using an overlapped subarray architecture
October 12, 2010
Conference Paper
Published in:
2010 IEEE Int. Symp. on Phased Array Systems, 12 October 2010, pp. 713-718.
Summary
The measured results from an X-band electronically scanned array using an overlapped subarray architecture are presented. The 2D architecture uses a 12 x 12 element subarray with 3 to 1 overlapping. The active electronic scanned array is a receive only implementation consisting of switch, low noise amplifier, phase shifter and attenuator. Measured far-field patterns and excitation at the aperture using near-field scanner demonstrates desired design goals of a 20 degree sector beam with low sidelobes. Finally, the scan performance of the sector subarray beam is measured at 20 and 40 degrees. A three tile implementation is constructed and measured.
Summary
The measured results from an X-band electronically scanned array using an overlapped subarray architecture are presented. The 2D architecture uses a 12 x 12 element subarray with 3 to 1 overlapping. The active electronic scanned array is a receive only implementation consisting of switch, low noise amplifier, phase shifter and...
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