Transcript Army’s Digital Array Radars Dr. Rich Wittstruck October 11, 2007

Army’s Digital Array Radars
October 11, 2007
U.S. Army . Program Executive Office, Intelligence, Electronic Warfare & Sensors
Dr. Rich Wittstruck
[email protected]
Unclassified
Unclassified
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OCT 07Nov
. Wittstruck
IDGA11Sensors
06 (1) (1)
Today’s Counterfire Radar Capabilities
50 km
Rocket
Mortar
Mortar
6.5 km
Cannon
Rocket
24 km
18 km
30 km
14.5 km
Cannon
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
AN/TPQ-36(8)
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Mortars: 0.75-18km
Medium Cannon: 3-14.5km
Rockets: 8-24km
90° Coverage
Improved Processor On-going
AN/TPQ-37(8)
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Medium Cannon: 3-30km
Rockets: 3-50km
90o Coverage
RMI Initiative
Long Range software initiative in
SWBII+ adds 120KM mode
Unclassified
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IDGA11Sensors
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GIRAFFE
BACKGROUND
• Air defense radar with an added
Counterfire mode
• Countefire performance acceptable for
limited target sets
Unclassified
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IDGA11Sensors
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Radar Processor Replacement
TPQ-37
Common
Processor
TPQ-36/37
Upgrade
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128 circuit cards (86 unique)
20 cubic feet
3 KW of power
Complex “wired” backplane
Non-programmable
No growth
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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
Unclassified
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IDGA11Sensors
06 (4) (4)
Transmitter Upgrade
Transmitter/Cooler
Unclassified
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IDGA11Sensors
06 (5) (5)
Radar LRUs
Unclassified
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IDGA11Sensors
06 (6) (6)
EQ - 36
Q37 Capabilities
60Km
• 90º Range
• Mortars – 0.5 to 20 km
• Artillery – 3 to 32 km
Q36 Footprint
Rocket
32Km
Cannon
20Km
Mortar
• Rockets – 15 to 60 km
OR
• Solid State Antenna
3Km
• Remote Operations
• 360º Range (Mortars)
•Light - 3 to 10 km
Medium – 3 to 12 km
Heavy – 3 to 15 km
• Prognostics Maintenance
Mortar
Cannon
15 Km
• Crew size 4
• Single C-130 lift
• Single vehicle
• Improved Clutter Mitigation
• Warn
Unclassified
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. Wittstruck
IDGA11Sensors
06 (7) (7)
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
Unclassified
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. Wittstruck
IDGA11Sensors
06 (8) (8)
Endstate
Army LCMR
SOF LCMR
Long Range
Counterfire Radar
E Q36 Increment I/II
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90° Coverage
60Km for Artillery
300Km Max Range for Missiles
Single Sortie C-130
MMR
ATNAVICS
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Counterfire Target Acquisition
Air Defense
Air Defense Fire Control
Air Traffic Control
Sentinel
Unclassified
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IDGA11Sensors
06 (9) (9)
The Path Forward
Unclassified
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IDGA11Sensors
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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.
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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
Unclassified
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OCT 07Nov
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IDGA11Sensors
06 (11) (11)
Comparison of Technology for S-Band PA
Parameters
RF Pout (W)
Gain (dB)
Driver RF Pout required (W)
Vbias (V)
number of MMICs for Pout and gain
Power density, W/mm, (HV-GaAs -estimated)
Gate length (um)
Gate periphery required (mm)
PAE %, (pwr MMIC only), (HV-GaAs -estimated)
Idc total (A), (pwr MMIC only)
Junctn Tmax, C ( to maintain during operation)
GaAs
HV-GaAs
PHEMT
GaN/SiC
HEMT consv pwr
GaN/SiC-2
HEMT -high
pwr density
PHEMT
25
20
0.4
9
2
0.8
0.25
31
35
7.94
150
SiC
MESFET
25
20
0.4
25
1
2.4
0.35
10
45
2.22
200
25
16
1.0
40
1
5.0
0.35
5
45
1.39
200
25
18
0.6
48
1
8.0
0.35
3
50
1.04
230
25
10
4.0
48
2+1
4.0
0.80
6
12
4.34
230
CW case
Pdc diss, W (Pdc - Prf)
Heat disspation / mm
Temperature rise, C
46.4
1.5
88
30.6
2.9
173
30.6
6.1
80
25.0
8.0
104
183.3
29.3
164
Max. base plate temp allowed to maintain Pout
62
27
120
126
66
Pulsed case (20% Duty cycle)
Pdc diss, W (Pdc - Prf)
Heat disspation / mm
Temperature rise
9.29
0.15
17.67
6.11
0.23
27.21
6.11
0.05
1.32
5.00
0.04
1.04
36.67
0.56
6.25
Max. base plate temp allowed to maintain Pout
132
173
199
229
224
90
1.33
90
1.00
95
4.17
System Considerations
Voltage Conversion Eff. (from 48V DC), estimates
I*R Losses (relative to lowest, 1)
67
7.62
81
2.13
Final system power conver. includes: base plate temp, Voltage conversion, I 2R loss for the array
Technology Maturity
9
5
3-4
3
5
Ready for prototype MMICs
TRL
now
now
FY06
FY07
now
Avail in systems, time depends on MTTF reqt
now
FY07
FY08
FY09
FY07
Unclassified
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IDGA11Sensors
06 (12) (12)
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
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Use multiple pulses
Increase transmission power
Require very high SFDR
Require super oscillators…
RF in
LNA
- Limited Performance:
-
IF
LF
Doppler-range ambiguity
A/D
LO
Unclassified
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. Wittstruck
IDGA11Sensors
06 (13) (13)
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
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Study the experimental feasibility of interferoceiver
- Fiber recirculation loop experiment
- Technology survey
Unclassified
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IDGA11Sensors
06 (14) (14)
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
fiber
RFin
L1
λ
Laser
Self-correlation data in
EDFA
∆l
Coupler
Modulator
Interference combiner
+sq law detector
1x2
L2
filter
A/D
φ
t2
Fourier Transform
F ( )  n f (tn ) Exp(itn )
Unclassified
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IDGA11Sensors
06 (15) (15)
Photonic Pulse Doppler Radar / Experimental
System Design:
Trange
Pulse Doppler Radar:
t
Tpulse
RF in
Receive antenna
Optical Amplifier/absorber
Doppler out
λ1
Laser
Modulator
Laser
WDM
WDM
λ2
Coupler
φ
Modulator
RFLO
Unclassified
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IDGA11Sensors
06 (16) (16)
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
Unclassified
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IDGA11Sensors
06 (17) (17)
BACKUP
Unclassified
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IDGA11Sensors
06 (18) (18)
RF-Photonic Interferoceiver
One pulse can determine Doppler Beating
Reflected
Original
Optical Fiber
Recirculation
Loop
SQUARE
LAW RF
Optical Fiber
Recirculation
Loop
RECEIVER
Both loops have the same length L
Interfering Amplitudes
Intensity Variation
Exp{i
n is the number of circulations
nL
2v nL
} f '( )  Exp{i (1  ) } f ( )
c
c c
2v nL
nL
 d Exp{i (1  c ) c } f ( ) Exp{i c } f '*( )  c. c.
Unclassified
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. Wittstruck
IDGA11Sensors
06 (19) (19)
RF-Photonic Correlation Receiver For Channelizer
Self-Correlation in time domain

f (t n )  A* (t n )  A(t n ) 
 dtA (t  t
*
n
) A(t )  F ( )

Received RF
Optical Fiber
Recirculation
Loop L1
Transfer
Optical Fiber
Recirculation
Loop L2
ω
t
Time domain correlation spectrum analyzer:
But A/D sampling a CW signal.
Again, not a true time domain correlation!
t
Unclassified
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. Wittstruck
IDGA11Sensors
06 (20) (20)
True Correlation Receivers
True Time Domain Correlation
f (t n )  A* (t n )  B(t n )  F (n ); n   A   B
Received RF
Reference RF
Optical Fiber
Recirculation
Loop
Transfer
ω
t

f (t n )  A (t n )  A(t n ) 
Self-Correlator
*
*
dtA
 (t  tn ) A(t )  F ( )

Received RF
Optical Fiber
Recirculation
Loop: L1
Transfer
Optical Fiber
Recirculation
Loop: L2
t
ω
Unclassified
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. Wittstruck
IDGA11Sensors
06 (21) (21)
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)
For CW RF:
Cannot get info
with short pulse
Time domain
Received signal
f(ωt)
t
Reference (LO)
f(ωot)
Doppler
Frequency domain
We need to do correlation for pulse RF!
ωo
ω
Unclassified
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. Wittstruck
IDGA11Sensors
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