ADDITIONAL VALUE ON TRACKING PERFORMANCE OF BPSK WAVEFORM IN CAS - - PowerPoint PPT Presentation

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ADDITIONAL VALUE ON TRACKING PERFORMANCE OF BPSK WAVEFORM IN CAS - - PowerPoint PPT Presentation

Nov 06, 2022 321 likes β€’517 views

RELEASABLE FOR CONSTRUISONS ENSEMBLE PUBLIC DISCLOSURE LA DFENSE DE DEMAIN ADDITIONAL VALUE ON TRACKING PERFORMANCE OF BPSK WAVEFORM IN CAS TRANSMISSION P. MARLIER UNDERWATER WARFARE DEPT. SESSION : ACTIVE AND MULTI-STATIC SONAR PROCESSING

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CONSTRUISONS ENSEMBLE LA DÉFENSE DE DEMAIN

RELEASABLE FOR PUBLIC DISCLOSURE

ADDITIONAL VALUE ON TRACKING PERFORMANCE OF BPSK WAVEFORM IN CAS TRANSMISSION

  • P. MARLIER

UNDERWATER WARFARE DEPT.

SESSION : ACTIVE AND MULTI-STATIC SONAR PROCESSING

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

CONTENTS

  • Who ?
  • DGA Techniques navales
  • What ?
  • BPSK CAS project
  • Where ? When ?
  • The experimental setup
  • How ?
  • The signal processing chain
  • To what end?
  • Experimental results
  • And then ?
  • Future works
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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

Who ?

DGA, the French Defence Procurement Agency

French Navy DGA Naval Systems Industry players Academic Research

  • S&T activities
  • Defence Programs
  • Supervise defence equipment design and production
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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Enhance anti-submarine warfare frigates active capabilities
  • Pulsed sonar
  • Continuous sonar

CAS enhances virtually the pulse repetition rate

Transmitted waves Reflected waves

Wave amplitude Time Time Wave amplitude

What ?

CAS experimental project

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

Doppler-shift πš¬π’ˆ is related to the target kinematics

πš¬π’ˆ = π’ˆπ’”πŸ βˆ’ π’ˆπ’‡πŸ = π’ˆπ’‡πŸ . 𝑾𝒔𝑼 𝒅 = π’ˆπ’‡πŸ . 𝑾𝒔𝑴 + 𝑾𝒔π‘ͺ 𝒅

𝑾𝒔π‘ͺ = πš¬π’ˆ . 𝒅 π’ˆπ’‡πŸ βˆ’ 𝑾𝒔𝑴

North East 𝑾𝑴 𝑾π‘ͺ 𝑾𝑴 𝑾𝑼 𝑾𝒔𝑼 𝑾𝒔𝑴 𝑾𝒔π‘ͺ Frequency Transmitted π’ˆπ’–πŸ Reflected π’ˆπ’”πŸ Time πš¬π’ˆ

What ?

BPSK continuous transmission

  • Provide an additional observable dimension to the Kalman Filter

in Cartesian Coordinates

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Mediterranean Sea on July 2016
  • FREMM French Navy support
  • CAPTAS-4 from Thales Defence Mission Systems

Combined Active and Passive Towed Array System

  • Continuous Active BPSK transmission
  • Focus on fixed clutters

CAPTAS-4 system Courtesy of Thales Defence Mission Systems

Where ? When ?

The experimental setup

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • BPSK continuous transmission
  • 8 sub-band pulses
  • From 1.0 kHz to 2.2 kHz
  • 3.75 seconds for each sub-pulse

Frequency (Hz) Time (s)

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Array made up of 128 hydrophones

triplets

  • High capabilities in port-starboard discrimination using cardioid

beamforming

  • Signal averaging on each triplet to simplify processing chain

Triplet average Beamforming Matched filter Beam Collapse Extraction Tracking

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Beam width in broadside direction ~ 1Β°
  • Beam spacing reduced to ~ 0,25 Β° to reduce

tracking input sampling noise

  • Signal processed in the time domain
  • Hamming window
  • Temporal coherent processing

πŸ‘πœΎπŸ’ = πŸ”πŸΒ° 𝝁 𝑴 Triplet average Beamforming Matched filter Beam Collapse Extraction Tracking

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Doppler extraction by cross-correlation
  • Clutter with low relative radial speed (+/-1knots)
  • Doppler range depending on detection relative bearing

North East High positive radial speed High negative radial speed Low radial speed Fixed clutter

Cross-correlation between received signal and β€œDoppler-shifted” transmission

Triplet average Beamforming Matched filter Beam Collapse Extraction Tracking

+ 𝑾 π’π’ƒπ’š βˆ’ 𝑾 π’π’ƒπ’š 𝟏 Doppler (Knot) Detection Relative Bearing (Β°) 𝟘𝟏° 𝟏° πŸπŸ—πŸΒ°

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Merging cross-correlation results of each sub-band
  • f each ping in a given sector

Cross-correlation maximum level Arrival time

Triplet average Beamforming Matched filter Beam Collapse Extraction Tracking

Arrival time Associated Doppler values

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Tracking input from extracted data

Triplet average Beamforming Matched filter Beam Collapse Extraction Tracking

Transmission time (s) Array geographic position (rad, , rad ad) Array speed over ground (kn knots) Array course over ground (rad) Detection relative bearing (rad) Detection delay from transmission (s (s) Detection estimated Doppler (kn knots) Detection SNR (dB dB)

𝒖 𝝌, 𝒉 π’˜ 𝒍 𝜾 πš¬π’– 𝜽 𝑻𝑢𝑺

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Kalman Filter in Cartesian Coordinates
  • State Vector
  • Nearly Constant Velocity model
  • Measure Vector
  • Same initial state for both filters
  • Error prediction variance-covariance matrix adapted to each filter

Triplet average Beamforming Matched filter Beam Collapse Extraction Tracking

𝒀𝒍 = π’š, π’š , 𝒛, 𝒛 𝑼 𝒛𝒍 = 𝜾, 𝒆, 𝒔 𝑼 𝒛𝒍 = 𝜾, 𝒆 𝑼

How ?

The signal processing chain

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Statistics on Doppler distribution

Clutter detection

Doppler (Knot)

Noisy area

Doppler (Knot) 0,5 0,5

To what end ?

Experimental results

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Increased prediction filter accuracy

To what end ?

Experimental results

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Faster prediction filter convergence

To what end ?

Experimental results

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Processing continuous active BPSK wave transmission seems to

provide bearing, range and Doppler measurement with a high detection rate

  • Matched filtering with Doppler-shifted signal replicas allows fixed

clutter detection

  • Adding Doppler measure to the update vector shows good impact
  • n Kalman Filter performance
  • Prediction Accuracy
  • Convergence Speed

In conclusion

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DGA Techniques navales RELEASABLE FOR PUBLIC DISCLOSURE

  • Consolidate with more data
  • Exploit cardioid beamforming
  • Set other Doppler configuration (moving target)
  • Tracking through collapse beams image processing

THANK YOU FOR YOUR ATTENTION !

And then ?

Future works

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CONSTRUISONS ENSEMBLE LA DÉFENSE DE DEMAIN

RELEASABLE FOR PUBLIC DISCLOSURE

ANY QUESTIONS ?

SESSION : ACTIVE AND MULTI-STATIC SONAR PROCESSING