Multifunction Phased Array Radar (MPAR): Working Group Multifunction Phased Array Radar (MPAR): Potential to Support Homeland Defense and Security Missions Presented to: Interagency Air and Maritime Surveillance Summit II By: The MPAR Working Group Date: 05 June 2008 Federal Aviation Administration (FAA) Department of Homeland Security (DHS) National Oceanic and Atmospheric Adm. (NOAA) Department of Defense (DoD) Office of Federal Coordinator for Met. (OFCM)

Dr. James Kimpel Director, National Severe Storms Laboratory (NOAA) MPAR Working Group National Oceanic and Atmospheric Adm. (NOAA) Federal Aviation Administration (FAA) Department of Homeland Security (DHS) Department of Defense (DoD) Office of Federal Coordinator for Met. (OFCM) MPAR Working Group Multifunction Phased Array Radar (MPAR) 2 05 June 2008

Background - MPAR Program Origin NRC Report Beyond NEXRAD (2002), recommends PAR technology be developed as replacement for legacy weather radars In 2004, Federal Committee for Meteorological Services and Supporting Research (FCMSSR) directed an interagency Joint Action Group (JAG) be convened to assess R&D priorities for phased array radar OFCM-sponsored JAG published report, “Phased Array Radar R&D Needs and Priorities” in June 2006 DOC / NOAA DOT / FAA DOD / DHS SINGLE MPAR SYSTEM Weather & Aircraft Surveillance Weather Surveillance Noncooperative Aircraft Surveillance Today: OFCM-sponsored MPAR Working Group is working R&D Risk Reduction Strategies / Activities 3

Why Consider Weather Radar? Multi-mission capability is possible Weather radars already exist at ~190 locations Same technology holds promise for dramatically improving weather surveillance Can detect biological scatterers (birds, insects), smoke, volcanic ash, etc. Large potential cost savings

Existing Locations NEXRADs TDWRs

Nat. Weather Radar Testbed (NWRT) Currently Testing Multi-mission Capability Spy-1 Antenna

Current Research at the NWRT Improved weather surveillance (NOAA, FAA) Simultaneous weather and aircraft surveillance (DHS, FAA, NOAA) Wind farm clutter mitigation (DHS, NOAA) Long-Range Surveillance Severe Weather Non-Cooperative Targets Weather Fronts Terminal Surveillance Chemical Dispersion

Potential Cost Savings Joint Action Group Recommendations Today Future Concept Stove-piped Approach: ASR-9 ASR-11 Affordable Multifunction Phased Array Radar (MPAR) Sustain Partially Modernize Replace ASR-8 NWRT Proof-of-concept tests Develop scaled prototype and critical technologies Mid 2007-2012: Full-scale prototype & operational test 2010 - 2016: 2007: Define concept and R&D roadmap ARSR-1/2 ARSR-3 ARSR-4 Reduced number of radars - potentially saves $2B Consolidated maintenance and logistics infrastructure – potentially saves $3B NEXRAD TDWR 510 does not include training center radars, nor Alaskan, Hawaiian, Puerto Rican, Guamanian radars. 510* Radars, 8 Types 334 Radars, 1 Type 5000 ft AGL, Blue, weather only Includes Operational CONUS radar only 8

MPAR Operational View Potential Users: DOT/FAA/FHA NOAA/NSSL/NWS DOD/Navy/Army/USAF, DHS NASA, DOA, DOE, DOI, Others MPAR Operational View Long Range Surveillance Severe Weather Non-Cooperative targets Weather Fronts Highlights Multi-function Capability (aircraft, weather and other threats and special objects of interest, e.g., UAV, bird flocks, volcanic ash, etc.) Adaptable beamsteering allows the system to expend radar resources where they’re needed, when they’re needed, and for how long they’re needed (e.g., stare). - Revisit time based on object characteristics (e.g., faster revisit on a non-cooperative track in the terminal area vs. a cooperative track in the en route air space) - Flexible dwell time (e.g., allows radar to “stare” target of concern or at a tornado vortex) - Track mode (vs. track-while-scan) facilitates faster track update rates Full Volume Weather Scan and Fast Scan Region (e.g., faster update rate for area of interest such as a gust front) Chemical Dispersion Terminal Surveillance

Mr. William Benner Weather Group Manager AJP-B400 (FAA)

Air Traffic Control Radar Snapshot Air Traffic is expected to more than double by 2025 and will exacerbate the air traffic delay problem Weather accounts for 70% of all delays Current weather and surveillance radar networks are aging (new to 40 years old) Many are nearing the end of their service life FAA Enterprise Architecture Roadmaps include investment decision points for terminal radars (e.g., replacement vs. SLEP)

NextGen Motivation NextGen Air Transportation System Integrated Plan stipulates: “Develop a system-wide capability to Reduce Weather Impacts” “Research areas to develop enhanced weather observations and forecasts, and integrate them with decision support tools to enhance capacity and efficiency of the airspace while improving safety.” The FAA is migrating to Automatic Dependent Surveillance - Broadcast (ADS-B) concept The Surveillance/Positioning Backup Strategy Alternatives Analysis Report : “recommends that the FAA retain approximately one-half of the Secondary Radar Network as a backup strategy for ADS-B” “terminal area primary radar coverage will not be reduced from current levels” Mission Evaluate new technology in support of Next Generation Air Traffic Management (NextGen) system Support Joint Program Development Office (JPDO) 2025 vision for the NextGen Objective Develop affordable radar network for improved: Weather and surveillance for aviation safety Airport efficiency and capacity Homeland security Severe weather forecasting Natural disaster planning

MPAR Approach Potential for radar consolidation and fleet reduction (ASR, TDWR, NEXRAD, ARSR) Multi-mission capable Scalable to mission(s) needs Reduced O&M cost and consolidated maintenance, logistic and training programs. Improved reliability (electronically scanned vs. rotating) Weather Aircraft

Achieves an Affordable Phased Array Radar MPAR Assessment PAR performance is not an issue Major cost driver is the active array antenna PAR ‘Active Array’ development should exploit advances in: Military R&D Commercial technology/process Continue investigating advances in technology New semi-conductor materials Chip integration T/R module packaging Digital architectures Research & Development Goals Demonstrate affordability Verify technology performance (using COTS) Verify multifunction capability Achieves an Affordable Phased Array Radar

FAA Enterprise Architecture Surveillance and Weather Roadmaps 2011 - Decision Point (77) to implement NextGen primary radar system including weather surveillance requirements (aligns with JRC-1, Initial Investment Decision) 2014 - Decision Point (104) to replace legacy primary radars (ASR-8, ASR-9) based on air traffic safety, security and weather surveillance requirements 2018 - Decision Point (91) to SLEP Wind Shear systems, ASR-9/11 Wx Channel and NEXRAD or replace with NextGen Wx Surveillance Capability 2020 - Establishment of Acquisition Program Office (aligns with JRC-2B, Final Investment Decision) Surveillance and Weather Roadmaps are aligned (multifunction solution) Critical R&D activities required prior to the 2011 and 2014 Decision Point 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 77 104 91 New Primary Radar (Replaces ASR) NextGen Wx Radar Capability

Conclusion National primary radar network required for foreseeable future FAA requirement is a subset of the National Requirement Collaboration with other agencies is essential for best value solution MPAR is a technology research effort MPAR could be part of a multi-agency Family of Solutions

MIT Lincoln Laboratory Dr. Jeffrey Herd Dr. Mark Weber MIT Lincoln Laboratory

Outline Terminal MPAR Capabilities Technology Risk Reduction Program Summary

Terminal Area Primary Radar Missions ATC terminal radars support unique missions Low altitude wind shear protection at airports Thunderstorm monitoring (30 sec update) Non-cooperative aircraft surveillance (DoD, DHS) FAA Architecture identifies decision points for future terminal area primary radar 2011 - Decision to implement NEXTGEN primary radar system which includes weather surveillance requirements 2014 - Decision for replacement of legacy primary radar (ASR-8, ASR-9), based on air traffic safety, security and weather surveillance requirements We are going to focus on airport terminal area primary radars since these provide aviation-unique services including wind shear detection, fast-update mapping of thunderstorms and in some areas, non-cooperative aircraft surveillance for high-value assets. The FAA enterprise architecture documents identify a number of pertinent decision points including a 2011 decision whether to proceed a “NextGen” primary radar encompassing both ATC and weather surveillance capabilities and a 2014 decision on what to today about replacement of today’s airport surveillance radars.

Aircraft & Weather Surveillance Goals Terminal MPAR Aircraft & Weather Surveillance Goals Surveillance Type Maximum Range Maximum Altitude Position Accuracy Minimum Sensitivity Update Interval Lateral Vertical Aircraft 60 nm 20,000’ 600’ 1 m2 < 4.8 s Weather Microburst 5 nm Surface < 750’ N/A 0 dBZ 60 s (surface scan) Gust Front 20 nm Storm Structure < 8500’ 30 dBZ (volume scan)

Candidate Terminal MPAR Concept Aircraft Surveillance Active Array (planar, 4 faces) Diameter: 4 m TR elements/face: 5,000 Dual polarization Beamwidth: 1.2 (broadside) 2.0 (@ 45) Gain: > 40 dB Transmit/Receive Elements Wavelength: 10 cm (2.7–2.9 GHz) Bandwidth/channel: 1 MHz Pulse length: 80 s (1 s fill) Peak power/element: 5 W linear pol 10 W circular pol Architecture Overlapped subarray beamformers Number of subarrays: 24 Maximum # concurrent beams: 24 Aircraft Surveillance Weather Surveillance I’ll do this out of sequence and begin with a description of a terminal MPAR concept that meets the informal requirements I’ll discuss in the rest of this section. Won’t go through all the details but main points are: 4-faced active array antenna, each face sized so as to provide a physical beam width varying from 1.2 to 2.0 degrees depending on steering angle. This requires a total of about 20,000 transmt-receive elements in the radar. For various reasons the sweet spot as far wavelength is concerned in in the same 10cm band as our current ASRs and the NEXRAD national weather radar network. Bandwidth of 1 MHZ required and peak power per TR element of 5 W. An important part of the design is transmission and reception on two offset frequency channels and the use of a highly digitized, overlapped subarray architecture for the antenna array. These choices allow each face of the radar to simultaneously transmit and receive through two independently steerable beam clusters, each of which can receive up to 12 beams concurrently. As you’ll see this allows for very efficient management of the radar’s energy to meet necessary scan timelines for its various missions. 334 MPARS required to duplicate today’s airspace coverage. Half of these are scaled “Terminal MPARS” 21

Polarization Requirements Weather Aircraft Mode Polarization Weather Dual Linear Aircraft (clear) Single Linear Aircraft (rain) Circular

Adaptive Beam Clusters Low Elevation High Elevation 12° 6° 2° 2° 2° Aircraft (linear pol) Weather (dual pol) Aircraft (up to 24 linear pol beams) Weather (up to 12 dual pol beams) 20,000 ft Transmit Receive R max As noted, aircraft volume search scans of 3 to 6 seconds are needed to replicate ADS-B surveillance updates, and weather scan updates ranging from 30 seconds to 2 minutes are needed to replicate ASR-9/11 and TDWR weather scan update rates. Transmitted beam pattern is spoiled as appropriate for balancing necessary power on target with volume scan update requirements. On reception, full array utilized so as to maintain angular resolution. As I noted the array digitization enabled by the overlapped subarray architecture allows for the formation of pencil beam clusters spanning the angular interval illuminated by the transmitter At high elevation angles, the maximum range for surveillance drops off significantly for all functions so the transmit beam can be progressively spoiled to allow you to move very rapidly through those elevation angles.  R max = Max_Alt / sin (Ө)

TMPAR Scan Timing Summary Mode scheduling example: High fidelity weather scan update period Aircraft and rapid update weather scan update period 2.4 1.6 2.4 1.6 2.4 1.6 2.4 1.6 4 8 56 60 4 Time, sec Function Scan Update Period (sec) Aircraft “Track While Scan” 4 Rapid Update Weather Volume Scan High Fidelity Weather Volume Scan 60 Summary of nominal weather and aircraft scan timing summaries with our concept design. Weather update rate close to required ADS-B “hit rate” and weather and wind shear scans equal or exceed those achievable with today’s terminal ATC and weather radars. Note that adaptive scanning (as opposed to weather volume scan and aircraft “track while scan” could increase update rate substantially on high-value targets.

Notional TMPAR Air Vehicle ID Modes RFID Mode: High Doppler resolution (~1 Hz) to discriminate type (jet vs propeller vs bird), velocity spectrum, types of engines, number of engines High pulse repetition frequency (~15 kHz) High Range Resolution (HRR) Mode: Small range gates to discriminate length and image target Wide operating bandwidth (2.7 - 2.9 GHz) TMPAR hardware supports both RFID and HRR modes Capable of detecting < -20 dBsm targets out to 50 nm Aircraft Range-Doppler Image Minimum Detectable RCS vs Range 5000 elements 10 W peak 80 μs pulses Swerling type 1

Wind Farm Effects Mitigation Radar Return Windmill Doppler Spectrum* Wind Farm TMPAR vs ASR-9 Windmill Suppression Wind farm effects on primary radars High reflection levels causes automatic limiting RCS of 20 - 40 dBsm (aircraft is 10 – 30 dBsm) Doppler modulation causes false target signatures Blade tip velocities of 80 – 160 knots Narrow elevation beam of TMPAR suppresses low angle clutter return >35 dB improvement over ASR-9 in signal to clutter ratio for 5 kft target and wind farm at 10 nm > 35 dB * from ‘Feasibility of Mitigating the Effects of Wind Farms on Primary Radar’, Alenia Marconi Systems Limited

Outline Terminal MPAR Capabilities Technology Risk Reduction Program Summary

Terminal MPAR Challenges TMPAR Challenges: Ultra-low cost array (~ $50k / m2) Multiple independent beam clusters Scalable aperture sizes Open architecture Low operations and maintenance costs Enablers: Highly integrated T/R chips Design for manufacturability

Commercial vs Military MMIC* Costs NRE** Dominates Military Commercial Production DDG-1000 VSR Typical Commercial Single Part Volume TMPAR Typical military procurement volume is too small to fully amortize engineering development costs * Monolithic Microwave Integrated Circuit ** Non-Recurring Engineering

Terminal MPAR Cost Reduction Strategies Approach Impact Minimize HPA Power Lowers T/R module costs, allows air cooling Minimize # Beams Simplifies beamformers, reduces interconnects, reduces backend processing Scalable Panels Enables same array hardware for full scale and terminal area radars Tile Architecture Reduces interconnects, enables higher level of integration onto array face Custom T/R Chipset Lowers T/R module cost

Technology Risk Reduction Program 2008 Terminal MPAR Technology Risk Reduction Program Program Objectives: Design, fabrication, and testing of a prototype MPAR active phased array panel Detailed cost estimate utilizing best commercial practice for a large quantity procurement of panels Critical Development Tasks: Antenna elements and beamformers* Prototype panel with custom T/R chip set** Risk Definition and Mitigation Plan*,** Prototype panel test and evaluation* * MIT LL ** Subcontract to Tyco Electronics

Low Cost Panel Demonstration Aperture Face Panel: Including 64 Radiators, Beamformers, 64 T/R Elements, DC and Logic Distribution, Low Level Power Conditioning Custom Radiators and Beamformers Dual Pol Radiator Overlapped Subarray Backplane: Includes Beam Controller, Logic Fan Out, High Level Power Conditioning Custom T/R Chipset* Performance Testing 0.43 m Tx chip RX chip Heat Exchanger LNA / Limiter chip * Funded under Tyco Electronics IR&D

TMPAR Prototype Radar Notional Development Schedule Year 1 Year 2 Year 3 Year 4 Year 5 PDR CDR Testing CDR Low Cost Scalable Panel Demonstration Concept Development, Design, and Scaled Aperture Radar Demonstration Full Scale Fabrication Testing and Evaluation Panel Multiple Panel Array Full Scale Array Data Collection 8 x 8 Element Panel Array Measurements Waveform Design Systems Analysis 768 Element Array Radar Functionality Algorithm Dev System Simulation Analog and Digital Hardware: 4864 Element Array 48 Receiver Channels System Simulation Test Planning Collect Multimode Data Process Data Report Results Systems Analysis & Signal Processing:

Summary Specific concept for a Terminal Multifunction Phased Array Radar developed Provides primary radar services in lieu of ASR-8/9/11 and TDWR Can support backup or integrity verification for ADS-B TMPAR has the potential to support key needs of the DHS, DoD, FAA, and NWS with a single radar network Flexible electronic beamforming Multiple simultaneous high gain receive beams Open architecture signal & data processing Affordability being addressed through exploitation of commercial microwave technology Critical subsystems development and test underway Mitigate risk and advance ultra low cost design through industry partnership

Mr. Kevin “Spanky” Kirsch DHS S&T Special Program Director, DHS S&T Special Program

DHS Primary Radar Usage Customs and Border Protection (CBP) CBP Air and Marine Operations Center (AMOC) US Coast Guard Secret Service Immigration and Customs Enforcement (ICE) Federal Emergency Management Agency (FEMA)

Discussion Areas for Consensus Implementation Strategy: Initial Priority Risk Reduction Areas Technolgy Demonstration & Testing Multi-functionality and Testing System Costs – Business Case Trade Studies 37

Discussion Areas for Consensus Interagency Management Approach Address Urgency Issues PD/Congressional Mandated Format: Past NEXRAD process (OFCM / NEXRAD Program Council / JSPO) Multi-Lateral Agency 38

QUESTIONS?

BACKUPS

Terminal MPAR Weather Sensitivity 1 s pulse no compression 80 s pulse 80x compression The parameters I showed you three charts ago lead to this function for T-MPAR minimun detectable weather reflectivity factor versus range. For reference we show the corresponding curve for TDWR which is the most sensitive operational weather radar in the U.S. inventory. Overall the sensitivity of our design is less than that of TDWR, particularly at short ranges where a long, 80 us transmitted pulse and pulse compression is not feasible. However, our design does maintain sensitivity less than 0 dBz which corresponds to a typical clear atmosphere cross section during summer months. At most U.S. airports this is more than sufficient for detection of wind shear phenomena as I will show in the next two charts. 5,000 modules @ 5 W per module provides 0 dBZ sensitivity to 60 nm

Target ID Mode Operating Parameters Radio Frequency Spectrum: 200 MHz 2 MHz WAS and RFID modes HRR mode 2.7 GHz 2.9 GHz Mode PRF (kHZ) Bandwidth (MHZ) Range Resolution (m) Doppler Resolution (Hz) Wide Area Surveillance (WAS) 1 2 100 10 RFID 15 HRR 200

ATC Cooperative Surveillance (ADS-B) Backup and Integrity Monitoring Backup needed in the event of a wide-area GPS outage (e.g. jamming, solar storms) or single-aircraft avionics failure Integrity monitoring needed to guard against “spoofing” FAA ADS-B backup strategy calls for retention of many legacy radars All primary radars Secondary radars in high density terminal airspace Backup strategy will be re-evaluated as experience with ADS-B is gained Alternatives under investigation include wide-area multilateration, DME, e-Loran and other non-radar alternatives (but these are all “cooperative”) Turn to MPARs possible role as a backup for the FAA’s defined next-generation ATC surveillance system. Chart summarizes FAA position.