Interferometric Measurements with Wideband Signal Processing Techniques

Bathymetric sonar systems are widely used nowadays in seafloor mapping and exploration. The differential phase technique, also known as interferometry, is widely used in these bathymetry measurement sonars, but the assessment of measurement uncertainty and data density are not completely understood and explored. This research paper concerns the description of measurement uncertainties due to different noise sources in interferometric sonars and a wideband signal processing approach to solve them. Interferometers are mostly used in shallow waters, e.g. lakes, inland waterways, rivers, reservoirs and coastal areas, due to having wider swaths compared to conventional multibeam echosounders or beamformers. This paper focuses on getting high-resolution bathymetry with minimum measurement uncertainty. It considers the effect of various acoustic noise sources, and neglects external error sources, e.g. INS, GNSS, sound velocity profiles. Wideband pulses are now used to overcome the range-resolution trade off problem of CW pulses. We have done an assessment of wideband signal processing techniques to reduce the bathymetry uncertainties caused by different noise sources. ITER Systems provided us with a Bathyswath-2 bathymetry system and essential surveying tools. Mathematical noise models are compared with data recorded in the field.