2019_programme: IMPROVED TRACKING OF A SURROGATE TARGET USING CONTINUOUS ACTIVE SONAR

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  • Session: 11. Large Time-Bandwidth acoustic signals for target detection and tracking
    Organiser(s): Tesei Alessandra
  • Lecture: IMPROVED TRACKING OF A SURROGATE TARGET USING CONTINUOUS ACTIVE SONAR [invited]
    Paper ID: 900
    Author(s): Bates Jeffrey, Canepa Gaetano, Tesei Alessandra
    Presenter: Bates Jeffrey
    Presentation type: oral
    Abstract: Increasing the duty cycle of traditional Pulsed Active Sonar (PAS) to approach that of a Continuous Active Sonar (CAS) mode is being investigated for Anti-Submarine Warfare applications including littoral scenarios. CAS offers the potential advantage of increasing the target update rate through sub-band processing to improve tracking performance. However this advantage needs to be experimentally confirmed as reducing the sub-band duration also negatively impacts the detection performance due to a reduction in the duration and bandwidth of the processed waveform.\nA sea trial was carried out by the Littoral CAS Multi-National Joint Research Project in the gulf of Taranto in October of 2016. Two LFM active sonar waveforms were simultaneously transmitted by the surface ship NRV ALLIANCE, to detect a simulated target (echo repeater) towed by the surface ship CRV LEONARDO. The first LFM waveform was 1 second in duration between 2700 and 3500 Hz (PAS). The second LFM waveform was 20 seconds in duration between 1800 and 2600 Hz (CAS). \nIn this work multi-static echo returns of the CAS and PAS waveforms, received by an autonomous underwater vehicle towing an array, are analyzed at the output of an M of N distributed multi-hypothesis tracker. The CAS waveform is sub-banded into seven 5 second long sub-pulses with a 50% overlap. To simulate a more realistic target the signal to noise ratio of the echoes from the omni-directional echo-repeater target were adjusted based on a bi-static target strength model. Four different values of N are selected and M is calculated based on an empirical model developed by Abraham in 2018. \nThe results demonstrate that, in the measured environment, CAS can reduce the false alarm rate compared to a conventionally processed PAS waveform at the output of a distributed multi-hypothesis tracker.
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  • Corresponding author: Mr Bates Jeffrey
    Affiliation: Defence Research and Development Canada
    Country: Canada
    e-mail:

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