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

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?

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..

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.

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

National Weather Radar Testbed

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. 2003 – 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

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.

Legacy Radars FAA NWS FAA Potential Savings ARSR TDWR Long Range Radars 97 3 Types Weather Radars 199 2 Types NWS NEXRAD FAA ASR Currently 7 legacy radars Legacy 526 MPAR 311 Diff. 41% -215 Terminal Area Radars 230 2 Types Potential Savings AFFORDABILITY R&D GOAL MPAR $/Unit = Legacy $/Unit

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

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.

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

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 30-45 minutes in advance. (Warn on FORECAST )

Future Tornado Warning Issues at time t=0 min.

Multi-functional Adaptive Scanning

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

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

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.

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

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?

QUESTIONS?

BACKUP SLIDES

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) 14 MPAR (Small) 25 Total 39 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)

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

NOAA Research Phase Actions Acquire SPY-1A based Phased Array Radar (PAR) (October 2003), $25M, Complete Engineering testing and evaluation (2003-2004), $1M, Complete Data Comparison, initial research (2004-2005), $2M, In progress Improved Scanning Strategies, Faster Scans (Beam Multiplexing), Initial Engineering to add Dual Polarization (2005-2006), $4M, In progress Add dual-polarization sub-array to PAR, (2007-2009), $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), (2011-2012), $12M, TBD