1 IDGA Sensors Nov 06 (1) Unclassified 11 OCT 07. Wittstruck (1) October 11, 2007 U.S. Army. Program Executive Office, Intelligence, Electronic Warfare.

1IDGA Sensors Nov 06 (1) Unclassified11 OCT 07 . Wittstruck (1)

October 11, 2007

U.S. Army . Program Executive Office, Intelligence, Electronic Warfare & Sensors

Unclassified

Army’s Digital Array Radars

Dr. Rich [email protected]


Today’s Counterfire Radar Capabilities

AN/TPQ-48(V)2

• 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

AN/TPQ-36(8) AN/TPQ-37(8)

50 km

Rocket

Cannon

30 km

Mortar

6.5 kmCannon

Mortar

Rocket

14.5 km

18 km

24 km


GIRAFFE

BACKGROUND

• Air defense radar with an added Counterfire mode

• Countefire performance acceptable for limited target sets


• 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

TPQ-36/37Upgrade

CommonProcessor

Radar Processor Replacement


Transmitter/Cooler

Transmitter Upgrade


Radar LRUs


EQ - 36

• Solid State Antenna

• Remote Operations

• Prognostics Maintenance

• Crew size 4

• Single C-130 lift

• Single vehicle

• Improved Clutter Mitigation

• Warn

• 90º Range

• Mortars – 0.5 to 20 km

• Artillery – 3 to 32 km

• Rockets – 15 to 60 km

• 360º Range (Mortars)

•Light - 3 to 10 km

Medium – 3 to 12

km Heavy – 3 to

15 km

15 Km

3Km

Mortar Cannon

OR

60Km

32Km

20Km

Rocket

Q37 Capabilities

Q36 Footprint

Cannon

Mortar


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

E Q36 Increment I/II

ATNAVICS

Sentinel

• 90° Coverage• 60Km for Artillery• 300Km Max Range for Missiles• Single Sortie C-130

Long Range Counterfire Radar

• Counterfire Target Acquisition• Air Defense• Air Defense Fire Control• Air Traffic Control

MMR

SOF LCMR Army LCMR


The Path Forward


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


Comparison of Technology for S-Band PAGaAs HV-GaAs GaN/SiC GaN/SiC-2 SiC

PHEMT PHEMTHEMT -

consv pwr HEMT -high pwr density MESFET

RF Pout (W) 25 25 25 25 25Gain (dB) 20 20 16 18 10Driver RF Pout required (W) 0.4 0.4 1.0 0.6 4.0Vbias (V) 9 25 40 48 48number of MMICs for Pout and gain 2 1 1 1 2+1Power density, W/mm, (HV-GaAs -estimated) 0.8 2.4 5.0 8.0 4.0Gate length (um) 0.25 0.35 0.35 0.35 0.80Gate periphery required (mm) 31 10 5 3 6PAE %, (pwr MMIC only), (HV-GaAs -estimated) 35 45 45 50 12Idc total (A), (pwr MMIC only) 7.94 2.22 1.39 1.04 4.34Junctn Tmax, C ( to maintain during operation) 150 200 200 230 230

Pdc diss, W (Pdc - Prf) 46.4 30.6 30.6 25.0 183.3Heat disspation / mm 1.5 2.9 6.1 8.0 29.3Temperature rise, C 88 173 80 104 164

Max. base plate temp allowed to maintain Pout 62 27 120 126 66

Pdc diss, W (Pdc - Prf) 9.29 6.11 6.11 5.00 36.67Heat disspation / mm 0.15 0.23 0.05 0.04 0.56Temperature rise 17.67 27.21 1.32 1.04 6.25

Max. base plate temp allowed to maintain Pout 132 173 199 229 224

Voltage Conversion Eff. (from 48V DC), estimates 67 81 90 90 95I*R Losses (relative to lowest, 1) 7.62 2.13 1.33 1.00 4.17

Final system power conver. includes: base plate temp, Voltage conversion, I2R loss for the array

TRL 9 5 3 - 4 3 5Ready for prototype MMICs now now FY06 FY07 nowAvail in systems, time depends on MTTF reqt now FY07 FY08 FY09 FY07

Parameters

CW case

Pulsed case (20% Duty cycle)

System Considerations

Technology Maturity


• 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

Conventional Radar:

“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.”

LNA

RF in

LO

LF A/DIF

Skolnik

The Philosophy of Radar Design


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 Interferoceiver For MicroDoppler Radar


RF - Photonic Correlation Receiver for Channelizer Concept

True time domain self correlation produced by the fiber recirculation loop

filter

Fourier Transform

Self-correlation data in

Laser Modulator 1x2

φ

λ

RFin

t1

EDFA

Optical Amplifier

Coupler

t2

L1

L2

fiber

Interference combiner+sq law detector

A/D

)()()( nnntiExptfF

∆l

Astrophysicists are able to retrieve their signal 36dB below noise level!

(Joe Taylor)


Photonic Pulse Doppler Radar / Experimental

Laser

Laser

Modulator

Modulator

WDMφ

RFLO

λ1

λ2

RF inReceive antenna

Doppler out

System Design:

Pulse Doppler Radar:

tTpulse

Trange

Optical Amplifier/absorber

CouplerWDM


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 about speed 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


BACKUP


RF-Photonic Interferoceiver

One pulse can determine Doppler Beating

Reflected

Original

SQUARE

LAW RF

RECEIVER

Optical FiberRecirculation

Loop


Loop

Both loops have the same length L n is the number of circulations

Interfering Amplitudes

Intensity Variation

Exp inL

cf E xp i

v

c

nL

cf{ } ' ( ) { ( ) } ( ) 1

2

d Exp iv

c

nL

cf E xp i

nL

cf c c { ( ) } ( ) { } '* ( ) . .1

2


RF-Photonic Correlation Receiver For Channelizer

Self-Correlation in time domain

Received RFOptical FiberRecirculation

Loop L1


Loop L2

Transfer

t ω

Time domain correlation spectrum analyzer:But A/D sampling a CW signal.

t

Again, not a true time domain correlation!

)()()()()()( ** FtAttdtAtAtAtf nnnn


True Correlation Receivers

BAnnnnn FtBtAtf );()()()( *

)()()()()()( ** FtAttdtAtAtAtf nnnn

True Time Domain Correlation

Self-Correlator

Received RF

Reference RF


Loop

t

t

Received RF


Loop: L1


Loop: L2

Transfer

Transfer

ω

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)

t

ωωo

Received signalf(ωt)

Reference (LO)

f(ωot)

For CW RF: Time domain

Frequency domainDoppler

Cannot get infowith short pulse

We need to do correlation for pulse RF!

1 IDGA Sensors Nov 06 (1) Unclassified 11 OCT 07. Wittstruck (1) October 11, 2007 U.S. Army. Program Executive Office, Intelligence, Electronic Warfare.

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