Interferometric height estimation of the seafloor via synthetic aperture sonar in the presence of motion errors

An end-to-end simulated processing chain related to an existing synthetic a perture sonar (SAS) system is developed and described, including motion com pensation, efficient image formation and autofocus procedures. The processi ng is extended to include interferometric height estimation capability. It is the goal of the paper to study the application of interferometry to SAS systems in the presence of motion errors. The system is analysed with respe ct to motion errors and the subsequent damaging effects to both imaging and height estimation. Results using both measured and simulated data are pres ented. The problem is addressed with respect to both one-pass and two-pass imaging geometries, and it is hypothesised that for slowly varying target h eight, one-pass SAS interferometry may be a more robust imaging tool than c onventional SAS alone. The simulated results suggest that height informatio n is recoverable even in some situations in which the conventional SAS refl ectivity image is completely ruined by phase error induced blur. High-resol ution SAS imaging coupled with interferometric height estimation for seaflo or imaging has military applicability in mine detection or classification a nd in topographic mapping in preparation for an amphibious assault. Civilia n uses would include surveying of objects such as oil pipelines and seabed mapping.