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Timothy Marston

Principal Engineer





Department Affiliation



B.S. Electrical Engineering, Seattle Pacific University, 2004

M.S. Acoustics, Penn State, 2006

Ph.D. Acoustics, Penn State, 2009


2000-present and while at APL-UW

Three-dimensional observations of tidal plume fronts in estuaries using a synthetic aperture sonar array

Marston, T.M., C. Bassett, D.S. Plotnick, A.N. Kidwell, and D.A. Honegger, "Three-dimensional observations of tidal plume fronts in estuaries using a synthetic aperture sonar array," J. Acoustic. Soc. Am., 154, 1124-1137, doi:10.1121/10.0020671
, 2023.

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22 Aug 2023

Synthetic aperture sonar (SAS) systems are designed to observe stationary scatterers located near the sediment interface. Less commonly, a SAS system may be used to observe scattering features located above the sonar in the water column. The Undersea Remote Sensing (USRS) project, sponsored by the Office of Naval Research, was a collaborative Directed Research Initiative (DRI) focused on studying dynamic estuarine water column features. During the USRS DRI, researchers from multiple institutions gathered to observe tidal features at various estuaries along the coast of the United States using both in situ and remote sensing techniques, including SAS. The first studied estuary was the mouth of the Connecticut River (CTR). Data captured by a SAS system deployed during a tidal event were post-processed to create three-dimensional observations of the structure of the leading edge of the CTR's ebb plume front. From these observations, lobed structures similar in scale to previously reported instabilities are revealed, with the present observations providing additional insight regarding the structure of the bubble distribution behind the front. Velocity estimates of plume features were also determined from SAS data and shown to compare favorably with concurrent marine radar estimates.

Multi-sensor towbody: Expandable platform detects, geolocates and classifies UXO

Williams, K., T. Marston, and T. McGinnis, "Multi-sensor towbody: Expandable platform detects, geolocates and classifies UXO," Sea Technol., 62, 8-11, 2021.

1 Sep 2021

Spatially variant autofocus for circular synthetic aperture sonar

Marston, T., and J. Kennedy, "Spatially variant autofocus for circular synthetic aperture sonar," J. Acoust. Soc. Am., 149, 4078-4093, doi:10.1121/10.0005198, 2021.

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1 Jun 2021

Circular synthetic aperture sonar (CSAS) is a method for improving the resolution and target detection capabilities of a synthetic aperture sonar system. CSAS data are difficult to focus because of their large aperture sizes and elevation sensitivity. This difficulty has sometimes been addressed by using transponders or distributing isotropic scatterers in the field of view of the system; however, this comes at the cost of reduced practicality. As an alternative, map-drift based multipoint autofocus ("multilateration") was proposed by Cantalloube and Nahum [IEEE Trans. Geosci. Remote Sens. 49, 3730-37 (2011)] for autofocusing analogous circular synthetic aperture radar data. Multilateration also solves the problem of aberration spatial variance by providing a three-dimensional navigation correction. In circular synthetic aperture focusing problems, though, correcting aberrations is a joint navigation and elevation estimation problem, and the present work extends the multilateration approach to simultaneously solve both a navigation solution and coordinate corrections for the multilateration control patches. Additionally, methods for addressing the stability and behavior of the inverse problem are addressed, and an adaptive weighting scheme for reducing the influence of outliers is presented. The field results demonstrate near optimal point-spread functions on distributions of natural isotropic scatterers and robustness in regions with bathymetric variability.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center