In these tutorials the use a daptive mesh refinement will be review Workbench 12.1
S pace- T ime A daptive M atched-field P rocessing (STAMP)
description
Transcript of S pace- T ime A daptive M atched-field P rocessing (STAMP)
Yung P. Lee(ASAP 2001, March 14, 2001)
Science Applications International Corporation
1710 SAIC Drive
McLean, VA 22102
Space-Time Adaptive Matched-field Processing (STAMP)
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Fourier Transform Spectral (Frequency) Content
Sonar Signal Processing Background
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Spatial Beamforming Direction (Angle) of Arrival (DOA)
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Matched Field Processing
Matched Field Processing 3D (Range,depth, bearing) Localization*1
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Matched Field Tomography Modal Information Environmental Info.
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Synthetic Aperture Matched Field Processing
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source at 76 m towed at 2.5 m/s from 9.18 km
Space Time Matched Field Processing
Matched Field Processing
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Space Time Matched Field Processing
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Localization & Doppler (velocity) Discrimination
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Phone-Doppler Space
Beam-Doppler Space
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BACKGROUND/OBJECTIVE
• Space-Time Adaptive Processing (STAP) coherently combines signals from the elements of an array and the multiple snapshots of signals, to achieve large spatial/temporal signal gain, to suppress interference, and to provide target detection in azimuth and velocity.
• Matched-field processing (MFP) coherently combines complex multi-path arrivals, to recover signal multi-path spreading loss and to provide range/depth localization.
• STAMP combines STAP and MFP to improve detection and localization performance for the mobile multi-line-towed-array sonar systems.
Azi
mu
th (
deg
)
0
90
180
Doppler (Hz)-fmax 0 fmax
Doppler (Hz)-fmax 0 fmax
Target
Target
Clutter (Bottom Bounce)
Clu
tter
(Bot
tom
Rev
erbe
ratio
n)
JammerJammer(own-ship)
FW
DA
FT
STAP
Detect the dot Null the Jammer and the slanted clutter
STAMP
Detect/combine/class/localize the dots Null the Jammer and the clutter
PassiveForward-sector processing
Cm ,fm
fm=f0*v/cm
Higher Mode (Path,Angle), Larger cm
Larger cm, Higher Angle (off horizontal), Smaller Doppler
C1 ,f1
Multi-path Doppler/Angle Spread
OUTLINE
• STAMP Processing
• Simulation scenario for forward-sector processing
• Simulation Results
Br(f0)
Beam-space replica
(Selected Beams and Dopplers)
Phone 1Line 1 x11(t)
Phone nLine 1 xn1(t)
Doppler Processing
X1(f)
Conventional Beamforming
B1(f)B(f)
Beam-Space Vector
(selected Beamsand Dopplers)
WB/NBAdaptive
MFP
Doppler Processing
Xr (f)
Conventional Beamforming
Br(f)
Phone 1Line k x1k(t)
Phone nLine k xnk(t)
Doppler Processing
Xk(f)
Conventional Beamforming
Bk(f)
Propagation Code to generate
Replicaxr(t)
OutputAmbiguity
SurfaceR,Zv
Space-Time Adaptive Matched-field Processing (STAMP)
SearchR,Zv
Forming Covariance
Matrix
R = < B(f) B+(f)>f
&Decomposition
B(f) = [B1(f)…. B1(f+mf),…….., Bk(f)…. Bk(f+mf)]
Bk(f) = [bk(f,1)…… bk(f,l)]
AELEnviron.
*Plane-wave ~ STAP
Adaptive Processing
)1(
w.r.t.Minimize
WWRWW
W
S
ARA
ARW
1
1
ARA 11
S
Adaptive Weight Vector
Adaptive Output
**A is the steering vector**R is the measured covariance matrix
ttt )()( xxR
High resolutionSidelobe suppressionSubject to mismatch – Robust Methods(widen the peak)
Wideband-Narrowband (WB/NB) Feedback-Loop White-Noise-Constrained (FLWNC)
Adaptive Processing
Br(f0)
Beam-space replica
(Selected Beams and Dopplers)
Covariance Matrix
R = < B(f) B+(f)>f
&Decomposition
VVλ nn
nnR
BRB
BRBBR
r1
r
r1
r
r1
1S
w
δw 2
1
2
BRB
BRRB
BRBBR
r 1
r
r 11
r
r 1
r
r 1
RS
w
2
δw 2
2
2
Adaptiveweight
W
VVλ
R nn
nn
1- 1
yes= s
yes= s
no
no
WB/NBProcessingS(f)=W+B(f)
* B(f) is “narrowband” (single f) R and W are “broadband” (averaged over band of f)
Simulation Geometry (F=200 Hz) target(NB)=120 dB, own-ship(BB)=120 dB, bottom bounce(BB)=115 dB
WNL=70 dB, 0.1 random phase error
3 kts
3 kts
towed array
own-ship noise
bottom bounce
10 km
188 m
Single-Line
4-Line-Sequential
4-Line-Vertical
No environmental mismatch
Single-Line BTRs of Each Signal ComponentForward Endfire at 0o
Own-Ship Noise Bottom Bounce
Target
__ Own-ship__ Bottom Bounce__ Target
Responses at 10o Azimuth
Single-Line Doppler/Azimuth Responses integration time =256-sec, Target Range=10 km, Forward Endfire at 0o
Own-Ship Noise Bottom Bounce
Target
__ Own-ship__ Bottom Bounce__ Target
Selected beams (0o-30o) &
Dopplers (6 bins for 6-kt search)
Responses at 10o Azimuth
Single-Line Beam/Cell Spectrograms
Conventional Plane-Wave (10o) Adaptive Plane-Wave (10o)
Adaptive MFP (target track)
__ Adaptive PW__ Adaptive MFP
Peak Level over Dopplers
Adaptive Beam/Cell Spectrograms
Adaptive Plane-Wave (10o) Single Vertical Adaptive MFP
4_Line_Vertical Adaptive MFP
__ PW__ Single Line MFP__ 4_Line_Vert MFP
Peak Level over Dopplers
Single Line, Conventional MFP
4_Line_Sequential, Adaptive MFP 4_Line_Vertical, Adaptive MFP
Single Line, Adaptive MFP
Array Size Dependence of MFP Range Tracking search at target depth and target speed
Depth Discrimination of Adaptive MFP Range Tracking 4_Line_Vertical Array search at target speed
Depth=10 m
Depth=180 mDepth=90 m
Depth=60 m
Speed= 3 m/s
Speed= -3 m/sSpeed= -1 m/s
Speed= 1 m/s
Speed Discrimination of Adaptive MFP Range Tracking 4_Line_Vertical Array search at target depth
SUMMARY
• STAMP processing that combines STAP and MFP has been developed.
• Simulations show that STAMP coherently combines signal multi-path spread in azimuth and Doppler and greatly enhances target detection as well as providing target range and depth classification and localization.