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Processor. Radar Processor Replacement. 5. IDGA Sensors Nov 06 (5 ) ... of different technologies; leading in cooling requirements. For a particular technology, ...
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Army’s Digital Array Radars October 11, 2007 U.S. Army . Program Executive Office, Intelligence, Electronic Warfare & Sensors Dr. Rich Wittstruck richard.wittstruck@us.army.mil Unclassified
50 km Rocket 30 km Cannon Today’s Counterfire Radar Capabilities 24 km Rocket Mortar Mortar 18 km 6.5 km 14.5 km Cannon AN/TPQ-48(V)2 AN/TPQ-36(8) AN/TPQ-37(8) • SOF system derivative fielded on operational needs statement • Only mortars: 1-6.5km • 360° coverage • Range and accuracy improvements in V3 • Mortars: 0.75-18km • Medium Cannon: 3-14.5km • Rockets: 8-24km • 90° Coverage • Improved Processor On-going • Medium Cannon: 3-30km • Rockets: 3-50km • 90o Coverage • RMI Initiative • Long Range software initiative in SWBII+ adds 120KM mode
GIRAFFE BACKGROUND • Air defense radar with an added Counterfire mode • Countefire performance acceptable for limited target sets
Radar Processor Replacement • 128 circuit cards (86 unique) • 20 cubic feet • 3 KW of power • Complex “wired” backplane • Non-programmable • No growth TPQ-37 • New modern architecture • 100% COTS technology • Non-proprietary • Open architecture • Supports future software requirements • Leverages MPQ-64 software • 3 VME cards • Lighter weight • 0.2 KW of power • Commonality with AN/TPQ-36(V)8 Radar Processor Common Processor TPQ-36/37 Upgrade
Transmitter Upgrade Transmitter/Cooler
3Km Mortar Cannon 15 Km EQ - 36 Q37 Capabilities Q36 Footprint 60Km Rocket • 90º Range • Mortars –0.5 to 20 km • Artillery – 3 to 32 km • Rockets – 15 to 60 km 32Km Cannon Mortar 20Km OR • Solid State Antenna • Remote Operations • Prognostics Maintenance • Crew size 4 • Single C-130 lift • Single vehicle • Improved Clutter Mitigation • Warn • 360º Range (Mortars) • Light - 3 to 10 km Medium – 3 to 12 km Heavy – 3 to 15 km
General Considerations • Use of spectrum • Size/Weight/Power • Q37+ performance in Q36 footprint (90 Degree) • Add 360 degree capability • “-ilities”, especially: • Mobility/Transportability • Survivability • Reliability/maintainability
Endstate Army LCMR SOF LCMR Long Range Counterfire Radar • 90° Coverage • 60Km for Artillery • 300Km Max Range for Missiles • Single Sortie C-130 E Q36 Increment I/II MMR ATNAVICS • Counterfire Target Acquisition • Air Defense • Air Defense Fire Control • Air Traffic Control Sentinel
Assumptions used in Technology Assessment Objective: To establish a working template to assess various device technologies for a power transmitter used in different system requirements. • Solid-state phased array system • Output power per element: 25W • Mode of operation: CW and Pulsed • Final performance can be scaled • Estimation of baseplate temperature needed to maintain PA MMIC(s) of different technologies; leading in cooling requirements • For a particular technology, overall system DC conversion efficiency and I2R distribution loss also to be considered to assess its advantage; trade-off should be noted
The Philosophy of Radar Design “There has been no significant change in Doppler Radar front-end architecture/concept since World-War II. The only difference in modern radar is the digital electronics for signal processing.” Skolnik Conventional Radar: • Super heterodyne receiver architecture/concept • - Theory was developed for CW RF • - Doppler or information detection achieved by frequency domain filtering • But, most modern Radar are pulsed Radar • Use multiple pulses • Increase transmission power • Require very high SFDR • Require super oscillators… • Limited Performance: • Doppler-range ambiguity RF in LNA IF A/D LF LO
RF-Photonic Interferoceiver For MicroDoppler Radar DARPA Funded Seeding Efforts at Army Research Lab: • Investigate the MicroDoppler signature • Theoretical modeling and simulation • MicroDoppler detection • Noise analysis • Study the experimental feasibility of interferoceiver • Fiber recirculation loop experiment • Technology survey
RF - Photonic Correlation Receiver for Channelizer Concept True time domain self correlation produced by the fiber recirculation loop • Astrophysicists are able to retrieve their signal 36dB below noise level! (Joe Taylor) t1 Optical Amplifier Self-correlation data in fiber EDFA ∆l RFin L1 λ Interference combiner +sq law detector Coupler filter A/D Laser Modulator 1x2 φ L2 t2 Fourier Transform
Trange System Design: Photonic Pulse Doppler Radar / Experimental Pulse Doppler Radar: t Tpulse Receive antenna RF in Optical Amplifier/absorber Doppler out λ1 Laser Modulator WDM WDM λ2 φ Coupler Laser Modulator RFLO
Let’s Transition This Technology • So that the future RF Radar systems can: • Use single transmit / receive pulse • Don’t worry about SFDR • Don’t worry aboutspeed and bandwidth of A/D • Ultra wide band and frequency agile • Channelizing with extreme large number of channels (large bandwidth, high resolution) • 1 Hz resolution micro Doppler detection • Precise range and Doppler for long distance high speed target • Detect small signal from the noise floor
Optical Fiber Recirculation Loop Reflected SQUARE LAW RF RECEIVER Optical Fiber Recirculation Loop Original RF-Photonic Interferoceiver One pulse can determine Doppler Beating Both loops have the same length L n is the number of circulations Interfering Amplitudes Intensity Variation
Optical Fiber Recirculation Loop L1 Received RF Transfer Optical Fiber Recirculation Loop L2 ω t RF-Photonic Correlation Receiver For Channelizer Self-Correlation in time domain Time domain correlation spectrum analyzer: But A/D sampling a CW signal. Again, not a true time domain correlation! t
True Correlation Receivers True Time Domain Correlation Received RF Optical Fiber Recirculation Loop Transfer Reference RF t ω Self-Correlator Optical Fiber Recirculation Loop: L1 Received RF Transfer Optical Fiber Recirculation Loop: L2 t ω
True Correlation Receiver • The Power of Time Domain True Correlation Receiver • Astrophysicists are able to be able to retrieve their signal 36dB below noise level! (Joe Taylor) Cannot get info with short pulse For CW RF: Time domain Received signal f(ωt) t Reference (LO) Doppler f(ωot) Frequency domain We need to do correlation for pulse RF! ωo ω