Publication List
Below is a list of peer-reviewed journal publications and conference proceedings.
Peer-Reviewed Journal Publications
Measurement of autoproduct fields in a Lloyd’s mirror environment
Jessica E. Lipa, Brian M. Worthmann, and David R. Dowling
Journal of the Acoustical Society of America (Apr 2018)
doi.org/10.1121/1.5032200
Description: In this paper, the autoproduct fields predicted by the below theory paper were experimentally measured in a water tank. Using a 40-110 kHz pulse that was broadcast about half a meter away, strong correlations between autoproducts and out-of-band fields were found for frequency difference fields between 0 and 60kHz and frequency-sum fields between 110 kHz and 190 kHz.
Jessica E. Lipa, Brian M. Worthmann, and David R. Dowling
Journal of the Acoustical Society of America (Apr 2018)
doi.org/10.1121/1.5032200
Description: In this paper, the autoproduct fields predicted by the below theory paper were experimentally measured in a water tank. Using a 40-110 kHz pulse that was broadcast about half a meter away, strong correlations between autoproducts and out-of-band fields were found for frequency difference fields between 0 and 60kHz and frequency-sum fields between 110 kHz and 190 kHz.
The frequency-difference and frequency-sum acoustic-field autoproducts
Brian M. Worthmann, and David R. Dowling
Journal of the Acoustical Society of America (May 2017)
doi.org/10.1121/1.4985440
Description: In this paper, the theory behind the autoproducts is explored via the Helmholtz equation, and in the ray-approximation, it is found that autoproducts behave like out-of-band fields whenever the ray's amplitude varies slowly compared to a wavelength, and when the difference in ray arrival times is much larger than the inverse of the available bandwidth. Additionally, field plots are constructed for a Lloyd's mirror environment, and the autoproduct's limitations near the surface and near the source are mathematically explained.
Brian M. Worthmann, and David R. Dowling
Journal of the Acoustical Society of America (May 2017)
doi.org/10.1121/1.4985440
Description: In this paper, the theory behind the autoproducts is explored via the Helmholtz equation, and in the ray-approximation, it is found that autoproducts behave like out-of-band fields whenever the ray's amplitude varies slowly compared to a wavelength, and when the difference in ray arrival times is much larger than the inverse of the available bandwidth. Additionally, field plots are constructed for a Lloyd's mirror environment, and the autoproduct's limitations near the surface and near the source are mathematically explained.
Adaptive frequency-difference matched field processing for high frequency source localization in a noisy shallow ocean
Brian M. Worthmann, Heechun Song, and David R. Dowling
Journal of the Acoustical Society of America (Jan 2017)
doi.org/10.1121/1.4973955
Description: In this paper, adaptive MFP techniques such as MVDR, MCM, MUSIC, and Matched Mode Processing, are applied to frequency-difference MFP. Additionally, an SNR study was performed to determine how sensitive various localization parameters are to genuine environmental noise. It was determined that in the KAM11 experiment, Matched Mode Processing performed the best, and that localization could be performed down to 0 dB SNR.
Brian M. Worthmann, Heechun Song, and David R. Dowling
Journal of the Acoustical Society of America (Jan 2017)
doi.org/10.1121/1.4973955
Description: In this paper, adaptive MFP techniques such as MVDR, MCM, MUSIC, and Matched Mode Processing, are applied to frequency-difference MFP. Additionally, an SNR study was performed to determine how sensitive various localization parameters are to genuine environmental noise. It was determined that in the KAM11 experiment, Matched Mode Processing performed the best, and that localization could be performed down to 0 dB SNR.
High frequency source localization in a shallow ocean sound channel using frequency difference matched field processing
Brian M. Worthmann, Heechun Song, and David R. Dowling
Journal of the Acoustical Society of America (Dec 2015)
doi.org/10.1121/1.4936856
Description: In this paper, the frequency-difference autoproduct is defined, and is applied to MFP for the purposes of source localization. Shallow ocean data from the KAM11 experiment is used, and successful localization is found for sources broadcasting 10-30 kHz over a 3 km range in a 106 meter deep, downward refracting sound channel.
Brian M. Worthmann, Heechun Song, and David R. Dowling
Journal of the Acoustical Society of America (Dec 2015)
doi.org/10.1121/1.4936856
Description: In this paper, the frequency-difference autoproduct is defined, and is applied to MFP for the purposes of source localization. Shallow ocean data from the KAM11 experiment is used, and successful localization is found for sources broadcasting 10-30 kHz over a 3 km range in a 106 meter deep, downward refracting sound channel.
Conference Proceedings
ICA 2016: Nonlinear signal processing techniques for active sonar localization in the shallow ocean with significant environmental uncertainty and reverberation
Brian M. Worthmann and David R. Dowling
International Congress on Acoustics: Buenos Aires, Aug 2016
doi.org/10.1121/2.0000309
Description: In this paper, active sonar simulations suggest frequency-difference-autoproduct-based techniques can out-perform matched filter techniques, even in the presence of environmental mismatch and strong reverberation. These techniques are particularly useful for localizing (in both depth and range) strong scatterers in the middle of the water column, away from the more strongly scattering surface and bottom.
Brian M. Worthmann and David R. Dowling
International Congress on Acoustics: Buenos Aires, Aug 2016
doi.org/10.1121/2.0000309
Description: In this paper, active sonar simulations suggest frequency-difference-autoproduct-based techniques can out-perform matched filter techniques, even in the presence of environmental mismatch and strong reverberation. These techniques are particularly useful for localizing (in both depth and range) strong scatterers in the middle of the water column, away from the more strongly scattering surface and bottom.
WESPAC 2015: High Frequency Source Localization in Shallow Ocean Sound Channels Using Frequency Difference Matched Field Processing
Brian M. Worthmann, Heechun Song, and David R. Dowling
Western Pacific Acoustics Conference: Singapore, Dec 2015
goo.gl/7wXnHr
Description: In this paper, preliminary results of frequency difference MFP as applied to simulated data and experimental data from KAM 11 are shown. Particularly, the robustness to source waveform was demonstrated using a chirp and part of a communications signal.
Brian M. Worthmann, Heechun Song, and David R. Dowling
Western Pacific Acoustics Conference: Singapore, Dec 2015
goo.gl/7wXnHr
Description: In this paper, preliminary results of frequency difference MFP as applied to simulated data and experimental data from KAM 11 are shown. Particularly, the robustness to source waveform was demonstrated using a chirp and part of a communications signal.
Last updated: 4/26/2018
