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

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


  1. RELEASABLE FOR CONSTRUISONS ENSEMBLE PUBLIC DISCLOSURE LA DÉFENSE 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

  2. CONTENTS RELEASABLE FOR PUBLIC DISCLOSURE  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 ? 2 • Future works 11/06/2018 DGA Techniques navales

  3. RELEASABLE FOR Who ? PUBLIC DISCLOSURE DGA, the French Defence Procurement Agency  Supervise defence equipment design and production Academic Research DGA Naval Industry French Navy Systems players  Defence Programs  S&T activities 3 11/06/2018 DGA Techniques navales

  4. RELEASABLE FOR What ? PUBLIC DISCLOSURE CAS experimental project  Enhance anti-submarine warfare frigates active capabilities Reflected waves Transmitted waves  Pulsed sonar  Continuous sonar Wave amplitude Wave amplitude Time Time 4 CAS enhances virtually the pulse repetition 11/06/2018 rate DGA Techniques navales

  5. RELEASABLE FOR What ? PUBLIC DISCLOSURE BPSK continuous transmission  Provide an additional observable dimension to the Kalman Filter in Cartesian Coordinates 𝑾 𝒔𝑼 North 𝑾 𝑼 𝑾 𝒔𝑪 Frequency 𝑾 𝑪 𝑾 𝑴 𝑾 𝒔𝑴 Reflected 𝒈 𝒔𝟐 𝑾 𝑴 Transmitted 𝒈 𝒖𝟐 𝚬𝒈 Time East Doppler-shift 𝚬𝒈 is related to the target kinematics 𝚬𝒈 = 𝒈 𝒔𝟐 − 𝒈 𝒇𝟐 = 𝒈 𝒇𝟐 . 𝑾 𝒔𝑼 = 𝒈 𝒇𝟐 . 𝑾 𝒔𝑴 + 𝑾 𝒔𝑪 𝒅 𝒅 5 𝑾 𝒔𝑪 = 𝚬𝒈 . 𝒅 − 𝑾 𝒔𝑴 11/06/2018 𝒈 𝒇𝟐 DGA Techniques navales

  6. RELEASABLE FOR Where ? When ? PUBLIC DISCLOSURE The experimental setup  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 CAPTAS-4 system Courtesy of Thales Defence  Focus on fixed clutters Mission Systems 6 11/06/2018 DGA Techniques navales

  7. RELEASABLE FOR How ? PUBLIC DISCLOSURE The signal processing chain  BPSK continuous transmission  8 sub-band pulses  From 1.0 kHz to 2.2 kHz  3.75 seconds for each sub-pulse Frequency (Hz) 7 11/06/2018 Time (s) DGA Techniques navales

  8. RELEASABLE FOR How ? Triplet average PUBLIC DISCLOSURE The signal processing chain Beamforming  Array made up of 128 hydrophones Matched filter triplets Beam Collapse Extraction Tracking  High capabilities in port-starboard discrimination using cardioid beamforming  Signal averaging on each triplet to simplify processing chain 8 11/06/2018 DGA Techniques navales

  9. RELEASABLE FOR How ? Triplet average PUBLIC DISCLOSURE The signal processing chain Beamforming  Beam width in broadside direction ~ 1° Matched filter 𝟑𝜾 𝟒 = 𝟔𝟏° 𝝁 Beam Collapse 𝑴 Extraction  Beam spacing reduced to ~ 0,25 ° to reduce Tracking tracking input sampling noise  Signal processed in the time domain  Hamming window  Temporal coherent processing 9 11/06/2018 DGA Techniques navales

  10. RELEASABLE FOR How ? Triplet average PUBLIC DISCLOSURE The signal processing chain Beamforming  Doppler extraction by cross-correlation Matched filter  Clutter with low relative radial speed (+/-1knots) Beam Collapse  Doppler range depending on detection relative bearing Extraction North + 𝑾 𝒏𝒃𝒚 High Tracking negative radial Doppler (Knot) speed Low 𝟏 radial speed High positive Fixed radial clutter − 𝑾 𝒏𝒃𝒚 speed 𝟏° 𝟘𝟏° 𝟐𝟗𝟏° East Detection Relative Bearing ( ° ) 10 Cross-correlation between received signal and 11/06/2018 “Doppler - shifted” transmission DGA Techniques navales

  11. RELEASABLE FOR How ? Triplet average PUBLIC DISCLOSURE The signal processing chain Beamforming  Merging cross-correlation results of each sub-band Matched filter of each ping in a given sector Beam Collapse Extraction Arrival time Arrival time Tracking Associated Doppler values Cross-correlation maximum level 11 11/06/2018 DGA Techniques navales

  12. RELEASABLE FOR How ? Triplet average PUBLIC DISCLOSURE The signal processing chain Beamforming  Tracking input from extracted data Matched filter 𝒖 Transmission time (s) Beam Collapse 𝝌, 𝒉 Array geographic position (rad, , rad ad) Extraction 𝒘 Array speed over ground (kn knots) Tracking 𝒍 Array course over ground (rad) 𝜾 Detection relative bearing (rad) 𝚬𝒖 Detection delay from transmission (s (s) 𝜽 Detection estimated Doppler (kn knots) 12 𝑻𝑶𝑺 Detection SNR (dB dB) 11/06/2018 DGA Techniques navales

  13. RELEASABLE FOR How ? Triplet average PUBLIC DISCLOSURE The signal processing chain Beamforming  Kalman Filter in Cartesian Coordinates Matched filter  State Vector Beam Collapse 𝑼 𝒀 𝒍 = 𝒚, 𝒚 , 𝒛, 𝒛 Extraction  Nearly Constant Velocity model  Measure Vector Tracking 𝒛 𝒍 = 𝜾, 𝒆 𝑼 𝑼 𝒛 𝒍 = 𝜾, 𝒆, 𝒔  Same initial state for both filters  Error prediction variance-covariance matrix adapted to each filter 13 11/06/2018 DGA Techniques navales

  14. RELEASABLE FOR To what end ? PUBLIC DISCLOSURE Experimental results  Statistics on Doppler distribution 0,5 0,5 Doppler (Knot) Doppler (Knot) Clutter detection Noisy area 14 11/06/2018 DGA Techniques navales

  15. RELEASABLE FOR To what end ? PUBLIC DISCLOSURE Experimental results  Increased prediction filter accuracy 15 11/06/2018 DGA Techniques navales

  16. RELEASABLE FOR To what end ? PUBLIC DISCLOSURE Experimental results  Faster prediction filter convergence 16 11/06/2018 DGA Techniques navales

  17. RELEASABLE FOR In conclusion 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 on Kalman Filter performance  Prediction Accuracy  Convergence Speed 17 11/06/2018 DGA Techniques navales

  18. RELEASABLE FOR And then ? PUBLIC DISCLOSURE Future works  Consolidate with more data  Exploit cardioid beamforming  Set other Doppler configuration (moving target)  Tracking through collapse beams image processing THANK YOU FOR YOUR ATTENTION ! 18 11/06/2018 DGA Techniques navales

  19. RELEASABLE FOR CONSTRUISONS ENSEMBLE PUBLIC DISCLOSURE LA DÉFENSE DE DEMAIN ANY QUESTIONS ? SESSION : ACTIVE AND MULTI-STATIC SONAR PROCESSING

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