Multifrequency Biplanar Interferometric Imaging

The resolution of 3-D imaging is greatly improved using a new multifrequency biplanar interferometry (MBI) technique. Using data from a multifrequency-acoustic pulse-echo system, ranges to coherent targets, estimated from propagation delays, and the phase differences between echoes received with four quadrants of a split-aperture array are converted to Cartesian distances, and transformed into Earth coordinates. The collective data set is interpolated to create a surface closely approximating the target's image. The resolution of the resulting image is improved orders of magnitude relative to those created with measures based on echo-intensity or single-frequency uniplanar interferometry. The effectiveness of MBI is demonstrated using data from a multifrequency (18 to 200 kHz) split-aperture echosounder system to produce composite high-resolution (submeter precision) images of the seabed sensed at long ranges (tens to hundreds of meters). MBI can be broadly applied to data from split-aperture remote-sensing systems which use acoustic or electromagnetic waves.

[1]  Laurent Berger,et al.  The new fisheries multibeam echosounder ME70: description and expected contribution to fisheries research , 2008 .

[2]  Geoffrey Shippey,et al.  Simple algorithms for sonar imaging and bathymetry with a linear swept-frequency (chirp) source , 1997, Int. J. Imaging Syst. Technol..

[3]  David A. Demer,et al.  An improved multiple-frequency method for measuring in situ target strengths , 2005 .

[4]  Xavier Lurton,et al.  An Introduction to Underwater Acoustics: Principles and Applications , 2010 .

[5]  L. Yang,et al.  Multibeam sonar bottom detection using multiple subarrays , 1997, Oceans '97. MTS/IEEE Conference Proceedings.

[6]  E. Armstrong,et al.  Experiments on the discrimination of fish and seabed echoes , 2004 .

[7]  P. Kraeutner,et al.  Multiangle Swath Bathymetry Sidescan quantitative performance analysis , 2002, OCEANS '02 MTS/IEEE.

[8]  Kenneth G. Foote,et al.  Coincidence echo statistics , 1996 .

[9]  Hughes Clarke,et al.  Applications of multibeam water column imaging for hydrographic survey. , 2006 .

[10]  George R. Cutter,et al.  A statistical-spectral method for echo classification , 2009 .

[11]  C. Moustier.  Signal Processing for Swath Bathymetry and Concurrent Seafloor Acoustic Imaging , 1993 .

[12]  Christian de Moustier,et al.  Differential Phase Estimation with the SeaMARC , 2004 .

[13]  C. Clay,et al.  Fundamentals of Acoustical Oceanography , 1997 .

[14]  P. Vogt,et al.  A Proposed International Long-term Project to Systematically Map the World's Ocean Floors from Beach to Trench: GOMaP (Global Ocean Mapping Program) , 2001 .

[15]  David A. Demer,et al.  A multiple-frequency method for potentially improving the accuracy and precision of in situ target strength measurements , 1999 .

[16]  J. S. Bird,et al.  Beyond interferometry, resolving multiple angles-of-arrival in swath bathymetric imaging , 1999, Oceans '99. MTS/IEEE. Riding the Crest into the 21st Century. Conference and Exhibition. Conference Proceedings (IEEE Cat. No.99CH37008).

[17]  Sébastien Bourguignon,et al.  Methodological developments for improved bottom detection with the ME70 multibeam echosounder , 2009 .

[18]  C. Moustier.  Coastal and Ocean Mapping Center for Coastal and Ocean Mapping 7-1988 State of the Art in Swath Bathymetry Survey Systems , 2018 .