First Result of Bistatic Forward-looking SAR
with Stationary Transmitter
Junjie Wu, Jianyu Yang, et.al.
Univ. of Electro. Sci. & Tech. of China
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Contents
1.Introduction
2.System Setup
3.Experimental result of
stationary transmitter BFSAR
4.Current work
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May, 12th, Sichuan
Mar, 11th, Tohuku
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1.Introduction
Forward-looking
Squint-looking
Side-looking
Squint-looking
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Backward-looking
1.Introduction
Forward-looking radar imaging：
• Obstruction warning
• Scene matching
guidance
• Self-landing
• Self-navigation
• Materials and/or troop
dropping
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Forward
looking radar
Forward
Squint SAR
Boresight
SAR
Forward
Squint SAR
Boresight
SAR
1.Introduction
Why can not SAR work in
forward-looking mode?
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1.Introduction
SAR imaging conditions：
Iso-range and Iso-Doppler lines —
• there is enough separation angle----2D resolution
• sole intersection----No ambiguity
Monostatic SAR
imaging area：
• Iso-range and IsoDoppler lines are
orthogonal
• Sole intersection
Monostatic SAR Iso-range and Iso-Doppler lines
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1.Introduction
Monostatic SAR
forward-looking area：
a
r
• Iso-range and IsoDoppler lines are parallel
• Double intersections
Monostatic SAR Iso-range and Iso-Doppler lines
Monostatic SAR：can not image the forward-looking area
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1.Introduction
What can we do?
Separate the transmitter and receiver
Bistatic
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1.Introduction
Bistatic SAR forwardlooking area：
• Iso-range and IsoDoppler lines are not
parallel
• Sole intersections
Bistatic SAR Iso-range and Iso-Doppler lines
Bistatic SAR：
can image the forward-looking area of the receive station
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1.Introduction
BFSAR with two moving platforms
• Transmitter Side-looking or Squint
• Receiver forward-looking
• Spaceborne transmitter——
Airborne receiver
• Airborne transmitter——
Airborne receiver
• Reconnaissance
• Self-navigation
• Air-drop
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Receiver
Forward-looking
Transmitter
Side-looking
BFSAR
1.Introduction
FGAN-Germany
• Spaceborne/airborne bistatic
backward-looking experiment
(2009.12)
Spaceborne transmitter
side-looking
Resolution：1-3m
Airborne receiver
backward-looking
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Area: 3×5km
1.Introduction
Stationary Transmitter (ST) BFSAR
Stationary transmitter
• Transmitter----high tower, mountain,
geostationary satellite, stratosphere low
speed airship…
• Receiver----airborne
Forward-looking Receiver
• Reconnaissance
• Self-navigation
• Air-drop
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1.Introduction
(a) monostatic FSAR
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Imaging principle of ST-BFSAR
(b) ST-BFSAR
2.System Setup
Stationary Transmitter
Vector Signal Generator
Agilent 8267D
target
Vehicle-borne Moving Receiver
Wideband signal receiver
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2.System Setup
System parameters
Carrier Frequency: 9.6GHz
Bandwidth: 80MHz
PRF: 500Hz
Pulse Width: 20us
Receiver velocity: 7m/s
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2.System Setup
Downward-looking
angle is too small
Target
Upward forward-looking
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Downward forward-looking
Equivalent
2.System Setup
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3. Experimental results
5
1800
9
1600
8
1400
7
1200
6
1000
5
800
4
600
3
400
2
200
1
0
0
0
1000
2000
3000
4000
5000
方位向采样点
6000
7000
8000
Slow time domain
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9000
x 10
0
1000
2000
3000
4000
5000
6000
方位向频率，采样点
7000
8000
Doppler domain
9000
3. Experimental results
Imaging result of ST-BFSAR
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4.Current Work
A
A
O
C
C
O
B
B
2D spatial
variance
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4.Current Work
Keystone-based azimuth nonlinear Chirp
Scaling imaging algorithm
Keystone transform:
Correct the linear range walk of all targets
----remove the variance of range migration
NLCS:
Equalize the FM rates of all targets
---- remove the variance of azimuth FM rate
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Thank you
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