Abstract
When isobath maps of the seafloor are constructed with a bathymetric sidescan sonar system the position of each sounding is derived from estimates of range and elevation. The location of each pixel forming the acoustic backscatter image is calculated from the same estimates. The accuracy of the resulting maps depends on the acoustic array geometry, on the performances of the acoustic signal processing, and on knowledge of other parameters including: the platform's navigation, the sonar transducer's attitude, and the sound rays' trajectory between the sonar and the seafloor. The relative importance of these factors in the estimation of target location is assesed. The effects of the platform motions (e.g. roll, pitch, yaw, sway, surge and heave) and of the uncertainties in the elevation angle measurements are analyzed in detail. The variances associated with the representation (orientation and depth) of a plane, rectangular patch of the seafloor are evaluated, depending on the geometry of the patch. The inverse problem is addressed. Its solution gives the lateral dimensions of the spatial filter that must be applied to the bathymetric data to obtain specified accuracies of the slopes and depths. The uncertainty in the estimate of elevation angle, mostly due to the acoustic noise, is found to bring the main error contribution in across-track slope estimates. It can also be critical for along-track slope estimates, overshadowing error contributions due to the platform's attitude. Numerical examples are presented.
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References
de Moustier, C., 1988, State of the Art in Swath Bathymetry Survey Systems,Int. Hyd. Review 65, 25–54.
de Moustier, C., 1993, Signal Processing for Swath Bathymetry and Concurrent Seafloor Acoustic Imaging, in: Moura & Lourtie (eds.),Acoustic Signal Processing for Ocean Exploration, NATO ASI, Kluwer, pp. 329–354.
Blackinton, J. G., 1986, Bathymetric Mapping with SeaMARC II: An Elevation Angle Measuring Side-Scan Sonar System, Ph.D. Dissertation, Hawaii Inst. of Geophys., Univ. of Hawaii, Manoa.
Matsumoto, H., Characteristics of SeaMARC II Phase Data,IEEE J. Oceanic Eng. 15, 350–360.
Masnadi-Shirazi, M. A., de Moustier, C., Cervenka, P., and Zisk, S. H., 1992, Differential Phase Estimation with the SeaMARC II Bathymetric Sidescan Sonar System,IEEE J. Oceanic Eng. 17, 239–251.
Blackinton, J. G., 1991, Bathymetric Resolution, Precision and Accuracy Considerations for Swath Bathymetry Mapping Sonar Systems, in:Proc. IEEE Oceans '91, Vol. 1, pp. 550–557.
Cobra, D. T., 1991, Estimation of Geometric Distortions in Side-Scan Images,Proc. IEEE OES Oceans '91 Conf.
Cervenka, P., de Moustier, C., and Lonsdale, P. F., 1990, Pixel Relocation in SeaMARC II Sidescan Sonar Images Based on Gridded Sea Beam Bathymetry,Eos Transactions, American Geophysical Union 71, 1407–1408.
Cervenka, P., de Moustier, C., and Lonsdale, P. F., 1991, Corrections on SeaMARC II Sidescan Sonar Bathymetry,Eos Trans. Am. Geophys. Un. 72, 249.
Cervenka, P., de Moustier, C., and Lonsdale, P. F., 1994, Geometric Corrections on Sidescan Sonar Images Based on Bathymetry. Application with SeaMARC II and Sea Beam Data,Marine Geophys. Res. (in press).
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On leave at the Naval Research Laboratory, Code 7420, Washington D.C. 20375-5350, U.S.A.
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Cervenka, P., Herzfeld, U.C. & De Moustier, C. Accuracy of the spatial representation of the seafloor with bathymetric sidescan sonars. Mar Geophys Res 16, 407–425 (1994). https://doi.org/10.1007/BF01270517
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DOI: https://doi.org/10.1007/BF01270517