Incoherent sub-band averaging for improved target detection and Doppler estimation in linearly frequency modulated continuous active sonar
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Abstract
Linear frequency modulated (LFM) continuous active sonar (CAS) waveforms show promise for use in target tracking given that waveforms can be split into sub-waveforms (sub-bands), thereby increasing the target refresh rate. However, reducing the duration and bandwidth of the sub-band decreases the SNR/SRR, adversely affecting detection. We present a target detection technique in which sub-bands are averaged incoherently while exploiting the range bias error (commonly observed in large duration LFM CAS waveforms with significant Doppler) to significantly improve detection. Sub-band averaging, known to reduce the false alarm rate, also mitigates channel coherence losses while maintaining detectability in CAS. A method for performing incoherent averaging over many possible Doppler shifts and identifying contacts via clustering in the 3-dimensional range-bearing-Doppler parameter space will be described. Finally, the promising results obtained with this technique on data acquired by the 2016 Littoral CAS Multi-National Joint Research Project sea trial will be shown.
Report Number
CMRE-PR-2019-041Source
In: Proceedings of Meetings on Acoustics, 175th Meeting of the Acoustical Society of America, volume 33, issue 1, 2018, doi: doi.org/10.1121/2.0000817Date
2019/05Author(s)
Bates, Jeffrey
; Grimmett, Douglas
; Canepa, Gaetano
; Tesei, Alessandra