1. 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)

2. 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

3. 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

4. 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

5. Existing Locations
NEXRADs
TDWRs

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

7. 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

8. 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 :
Full-scale prototype & operational test :
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

9. 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

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

11. 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)

12. 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

13. 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

14. 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

15. FAA Enterprise Architecture
Surveillance and Weather Roadmaps
Decision Point (77) to implement NextGen primary radar system including weather surveillance requirements (aligns with JRC-1, Initial Investment Decision)
Decision Point (104) to replace legacy primary radars (ASR-8, ASR-9) based on air traffic safety, security and weather surveillance requirements
Decision Point (91) to SLEP Wind Shear systems, ASR-9/11 Wx Channel and NEXRAD or replace with NextGen Wx Surveillance Capability
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

16. 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

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

18. Outline Terminal MPAR Capabilities Technology Risk Reduction Program
Summary

19. 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
Decision to implement NEXTGEN primary radar system which includes weather surveillance requirements
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.

20. 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)

21. Candidate Terminal MPAR Concept Aircraft Surveillance
Active Array (planar, 4 faces)
Diameter: m
TR elements/face: 5,000
Dual polarization
Beamwidth:  (broadside)
2.0 45)
Gain: > 40 dB
Transmit/Receive Elements
Wavelength: cm (2.7–2.9 GHz)
Bandwidth/channel: 1 MHz
Pulse length: 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

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

23. 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)

24. 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.

25. 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 ( 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

26. 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 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

27. Outline Terminal MPAR Capabilities Technology Risk Reduction Program
Summary

28. 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

29. 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

30. 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

31. 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

32. 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

33. TMPAR Prototype Radar Notional Development Schedule
Year Year Year Year 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:

34. 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

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

36. 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)

37. 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

38. 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

39. QUESTIONS?

40. BACKUPS

41. 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 5 W per module provides 0 dBZ sensitivity to 60 nm

42. 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

43. 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.