1. Multi-function Phased Array Radar Findings of the Joint Action Group
Dr. Mark Weadon
Executive Secretary
MPAR Work Group

2. Overview Motivation What is Phased Array Radar?
Advantages of PAR in Weather Surveillance
Multi-function Capability
PAR Affordability
Research Phase Objectives
Summary and Vision
Where Do We Go From Here?

3. Motivation for MPAR Research
NEXRAD and FAA’s Terminal Doppler Weather Radar are aging
systems. By 2020 both will be 30+ years old. No replacement
technology has been identified.
Potential of PAR for weather surveillance well documented:
National Research Council, Weather Radar Technology:
Beyond NEXRAD (2003)
Aerospace Corp, Future Weather Doppler Radar Feasibility
Study (2003)
Strategic Plan for U.S. Integrated Earth Observation System (2005)
Potential of PAR, military radar technology to ID very fast, very small airborne objects, well noted to meteorological applications..

4. Motivation for MPAR Research
In 2004 the Interdepartmental Committee for Meteorological Services and Supporting Research (ICMSSR) tasked a Joint Action Group (JAG) to assess multi-agency radar needs and to develop an Phased Array Radar Research and Development Plan.
Originally tasked to assess PAR solely as a weather surveillance capability, the JAG expanded its scope to include aircraft surveillance under the heading of a Multi-function Phased Array Radar (MPAR) needs assessment.

5. What is Phased Array Radar?
Planar phase front
Planar phase front
Electrical added phase delay
Mechanically Steered, Rotating Reflector Array
Electrically Steered, Fixed Phased Array

6. National Weather Radar Testbed

7. National Radar Testbed Milestones
National Severe Storms Lab (NSSL) accepts Spy-1 PAR from Navy (Oct. 2003)
NSSL assigned to keep PAR “in good working order” as per NOAA/FAA/Navy MOU (Oct. 2003)
Test and evaluation period underway (Oct – present)
NOAA funding for PAR ($1M) in place (Feb. 2004)
Substantial progress made with FAA funding (2004)
Spy-1 PAR begins to collect data; intercomparison studies performed with NEXRAD (May 2004 on)
National Radar Testbed becomes a national center Dec 2006

8. OFCM PAR Joint Action Group
Significant Findings
MPAR has potential to far exceed present radar capabilities and meet emerging requirements
MPAR offers improvement in spatial resolution, volume coverage, refresh rate, system reliability
MPAR offers prospect of a significant increase in tornado lead-times
PAR based on mature technology; low technical risk
Opportunity for system convergence: 526 NEXRAD and FAA radars in CONUS; same coverage could potentially be obtained from <335 MPARs
Lifecycle cost savings nearly $5B anticipated from radar convergence: $2B in acquisition and $3B in lifecycle sustainment
Seven- to ten-year intensive R&D effort required; estimated cost $200M
Methodology: assess radar needs among various federal agencies: both current and future. Then assess PAR likely capabilities and match against current and future agency needs.

9. Legacy Radars FAA NWS FAA Potential Savings
ARSR
TDWR
Long Range
Radars 97
3 Types
Weather Radars Types
NWS
NEXRAD
FAA
ASR
Currently 7 legacy radars
Legacy MPAR
Diff %
Terminal Area
Radars 230
2 Types
Potential
Savings
AFFORDABILITY R&D GOAL MPAR $/Unit = Legacy $/Unit

10. Meteorological Benefits Phased Array Radar (PAR)
More accurate, higher resolution data in space and time; earlier detection of tornado precursors
Less than 60 second complete volume scan rates possible vs. 4-5 minutes for NEXRAD
Dwell capability (aka “staring”) – intensive sampling in areas of interest throughout the volume
Adaptive scan strategies – ability to “tune” radar to weather at hand
Direct measurement of cross-beam winds; 3-D vector winds as storm-scale model input
Terrain following allows better characterization of critical boundary layer, less clutter
Graceful degradation – lower failure rate

11. NEXRAD-PAR Reflectivity Comparison
NWRT
Phased Array Radar
KTLX
WSR-88D
2nd Trip
NWRT Volume Scan in less than 1 min.
KTLX Volume Scan took 4.2 mins.

12. Composite Reflectivity: SPY-1 v. WSR-88D Hurricane Fran Remnants
Note heavy rain areas
5 minute volume scan
several second volume scan
SPY-1
NEXRAD

13. New Weather Warning Paradigm
Present – use NEXRAD radar to identify precursor signatures of tornadic storms, then extrapolate into the future. (Warn on DETECTION)
Future – use high-resolution PAR radar data to initialize cloud-resolving ensemble forecast models to identify precursors minutes in advance. (Warn on FORECAST )

14. Future Tornado Warning
Issues at time t=0 min.

15. Multi-functional Adaptive Scanning

16. Logistics Benefits of PAR
NO MOVING PARTS (4-faced array antenna)
Scalability with Common Building Blocks
Family of scalable radars - Economies of scale - Common Logistics/Maintenance - Common Technology Refresh
Improved Radar Performance - Increased Power - Increased Sensitivity - Operational Flexibility
Improved System Reliability
Thousands of Transmit/ Receive Modules per antenna face
Scalable antenna size
Solid-State Phased Array Radar Provides Significant Acquisition and Operational Benefits

17. Transmit/Receive (T/R) Module Cost Trends$
Estimated
Production
Cost ($K)
Prices for Solid-State T/R Modules are Trending Downward

18. Research Phase Objectives
Demonstrate PAR technology can be applied to the tornado detection, forecast, and warning mission in a multi-use environment.
Demonstrate affordability of prototype multi-function PAR
Establish metrics to assess progress of R&D strategy
Determine viable economic strategy that would permit a national PAR network to support NOAA, FAA, DOD, Homeland Security, and other national missions.

19. Summary and Vision
Cost of PAR components will decline significantly over next 5 to 10 years
Hypothesis: Multi-purpose PAR is feasible. System can simultaneously perform following functions:
Weather surveillance
Radar data assimilation into very high-resolution, very short- term, storm-scale forecast models
Aircraft tracking, both cooperative and non-cooperative
3-D measurements for dispersion winds
Chem/bio detection
Polarization diversity, multi-frequency, active PAR T/R elements already exist; technical risk is low
Must settle on best mechanism for government agencies to collaborate on a multi-purpose project of this magnitude

20. Where Do We Go From Here?
Establish MPAR risk reduction R&D on sound programmatic basis
Further refine agency radar mission requirements to provide operating threshold parameters for the MPAR prototype; thresholds must be specific and tied to missions
Build a compelling, rigorously fact-based business case for replacing legacy radars with MPAR
Align agency equities with investment commitment to MPAR risk reduction efforts and business case development
Research must answer following questions:
-- Is MPAR feasible? i.e. does the technology meet requirements?
-- Is it affordable? i.e. even if technology works, is it more cost effective in the long run to maintain legacy radars, or to replace them with an MPAR system?

21. QUESTIONS?

22. BACKUP SLIDES

23. MPAR vs. Legacy Radar Systems For EQUAL Surveillance Coverage (MIT-LL)
ARSR 9
ASR-9 24
ASR-11 9
TDWR 8
NEXRAD 14
Total 64
MPAR*
MPAR (Full)
MPAR (Small) 25
Total
North Eastern Corridor
Red – Legacy Coverage Better
Green – MFS Coverage Better
Grey – Coverage Equivalent
*Only 1 Type
*7 Different Types
25 Fewer
Radars
More Weather and Air Coverage to 1000 ft (AGL)

24. Research Cost Estimate
Dual-pol
Pre-prototype
PAR and modeling R&D

25. NOAA Research Phase Actions
Acquire SPY-1A based Phased Array Radar (PAR) (October 2003), $25M, Complete
Engineering testing and evaluation ( ), $1M, Complete
Data Comparison, initial research ( ), $2M, In progress
Improved Scanning Strategies, Faster Scans (Beam Multiplexing), Initial Engineering to add Dual Polarization ( ), $4M, In progress
Add dual-polarization sub-array to PAR, ( ), $28M, TBD
Test and Evaluate dual-polarized phased array capabilities, (2010), $6M, TBD
Research & Development towards operational applications to include assimilation of PAR data into numerical models and Short Range Ensemble Forecasts (SREF), ( ), $12M, TBD