S pace t ime a daptive m atched field p rocessing stamp
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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 [email protected] Sonar Signal Processing Background.

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S pace- T ime A daptive M atched-field P rocessing (STAMP)

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S pace t ime a daptive m atched field p rocessing stamp

Space-Time Adaptive Matched-field Processing (STAMP)

Yung P. Lee

(ASAP 2001, March 14, 2001)

Science Applications International Corporation

1710 SAIC Drive

McLean, VA 22102

[email protected]


Sonar signal processing background

Sonar Signal Processing Background

Fourier Transform Spectral (Frequency) Content

Spatial Beamforming Direction (Angle) of Arrival (DOA)


Matched field processing

Matched Field Processing

Matched Field Processing 3D (Range,depth, bearing) Localization

Matched Field Tomography Modal Information Environmental Info.


Synthetic aperture matched field processing

Synthetic Aperture Matched Field Processing

source at 76 m towed at 2.5 m/s from 9.18 km


Space time matched field processing

Space Time Matched Field Processing

Localization & Doppler (velocity) Discrimination

Matched Field Processing

Space Time Matched Field Processing

Phone-Doppler Space

Beam-Doppler Space


Background objective

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.


S pace t ime a daptive m atched field p rocessing stamp

STAP

Detect the dot

Null the Jammer and the slanted clutter

STAMP

Detect/combine/class/localize the dots

Null the Jammer and the clutter

0

90

180

FWD

Target

Jammer

(own-ship)

Jammer

Clutter (Bottom Bounce)

Clutter (Bottom Reverberation)

Azimuth (deg)

Target

Passive

Forward-sector processing

AFT

-Dfmax0 Dfmax

-Dfmax0 Dfmax

Doppler (Hz)

Doppler (Hz)


S pace t ime a daptive m atched field p rocessing stamp

Multi-path Doppler/Angle Spread

C1 ,Df1

Cm ,Dfm

Dfm=f0*v/cm

Higher Mode (Path,Angle), Larger cm

Larger cm, Higher Angle (off horizontal), Smaller Doppler


Outline

OUTLINE

  • STAMP Processing

  • Simulation scenario for forward-sector processing

  • Simulation Results


S pace t ime a daptive m atched field p rocessing stamp

Space-Time Adaptive Matched-field Processing (STAMP)

Doppler

Processing

Xr(f)

Conventional Beamforming

Br(f)

Propagation Code to generate Replica

xr(t)

Br(f0)

Beam-space replica

(Selected Beams and Dopplers)

AEL

Environ.

Search

R,Z,q ,v

*Plane-wave ~ STAP

WB/NB

Adaptive

MFP

Phone 1

Line 1 x11(t)

Doppler

Processing

X1(f)

Conventional Beamforming

B1(f)

Output

Ambiguity

Surface

R,Z,q ,v

B(f)

Beam-Space Vector

(selected Beams

and Dopplers)

Phone n

Line 1 xn1(t)

Forming

Covariance

Matrix

R = < B(f) B+(f)>f

&

Decomposition

Phone 1

Line k x1k(t)

Doppler

Processing

Xk(f)

Conventional Beamforming

Bk(f)

Phone n

Line k xnk(t)

Bk(f) = [bk(f,q1)…… bk(f,ql)]

B(f) = [B1(f)…. B1(f+mDf),…….., Bk(f)…. Bk(f+mDf)]


Adaptive processing

Adaptive Processing

Adaptive Weight Vector

Adaptive Output

**A is the steering vector

**R is the measured covariance

matrix

High resolution

Sidelobe suppression

Subject to mismatch – Robust Methods

(widen the peak)


S pace t ime a daptive m atched field p rocessing stamp

Wideband-Narrowband (WB/NB)

Feedback-Loop White-Noise-Constrained (FLWNC)

Adaptive Processing

Br(f0)

Beam-space replica

(Selected Beams and Dopplers)

yes

e = s

no

Covariance Matrix

R = < B(f) B+(f)>f

&

Decomposition

Adaptive

weight

W

no

yes

e = s

WB/NB

Processing

S(f)=W+B(f)

* B(f) is “narrowband” (single f)

R and W are “broadband” (averaged over band of f)


S pace t ime a daptive m atched field p rocessing stamp

Simulation Geometry (F=200 Hz)

target(NB)=120 dB, own-ship(BB)=120 dB, bottom bounce(BB)=115 dB

WNL=70 dB, 0.1 l random phase error

Single-Line

No environmental mismatch

4-Line-Sequential

4-Line-Vertical

3 kts

10 km

own-ship noise

towed array

188 m

3 kts

bottom bounce


S pace t ime a daptive m atched field p rocessing stamp

Own-Ship Noise

Bottom Bounce

Target

Responses at 10o Azimuth

__ Own-ship

__ Bottom Bounce

__ Target

Single-Line BTRs of Each Signal Component

Forward Endfire at 0o


S pace t ime a daptive m atched field p rocessing stamp

Own-Ship Noise

Bottom Bounce

Target

Responses at 10o Azimuth

__ Own-ship

__ Bottom Bounce

__ Target

Selected beams (0o-30o) & Dopplers (6 bins for 6-kt search)

Single-Line Doppler/Azimuth Responses

integration time =256-sec, Target Range=10 km, Forward Endfire at 0o


S pace t ime a daptive m atched field p rocessing stamp

Conventional Plane-Wave (10o)

Adaptive Plane-Wave (10o)

Adaptive MFP (target track)

Peak Level over Dopplers

__ Adaptive PW

__ Adaptive MFP

Single-Line Beam/Cell Spectrograms


S pace t ime a daptive m atched field p rocessing stamp

Adaptive Plane-Wave (10o)

Single Vertical Adaptive MFP

4_Line_Vertical Adaptive MFP

Peak Level over Dopplers

__ PW

__ Single Line MFP

__ 4_Line_Vert MFP

Adaptive Beam/Cell Spectrograms


S pace t ime a daptive m atched field p rocessing stamp

Single Line, Conventional MFP

Single Line, Adaptive MFP

4_Line_Sequential, Adaptive MFP

4_Line_Vertical, Adaptive MFP

Array Size Dependence of MFP Range Tracking

search at target depth and target speed


S pace t ime a daptive m atched field p rocessing stamp

Depth=10 m

Depth=60 m

Depth=90 m

Depth=180 m

Depth Discrimination of Adaptive MFP Range Tracking

4_Line_Vertical Array search at target speed


S pace t ime a daptive m atched field p rocessing stamp

Speed= 3 m/s

Speed= 1 m/s

Speed= -1 m/s

Speed= -3 m/s

Speed Discrimination of Adaptive MFP Range Tracking

4_Line_Vertical Array search at target depth


Summary

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.


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