High Frequency Motion Residuals: Analysis and Estimation

Brandon Maingot


Tuesday, Jul. 30, 2019, 2:00pm
Chase 130

Advances in multibeam sonar mapping and data visualization have increasingly brought to light the subtle integration errors remaining in bathymetric datasets. Continuously improving accuracy of the component sensors in integrated multibeam systems has resulted in integration errors, as opposed to sensor errors, now dominating depth residuals. Current field calibration procedures, the patch test, just account for static orientation bias and sonar to position latency. This ignores integration problems which generate often more subtle, time-varying depth errors. Such dynamic depth residuals can be the result of an unknown offset in sound speed, orientation, space or time. These residuals are systematic, and thus should be predictable based on their geometric relationship between the input data and integrated output. A first attempt at addressing this problem utilized correlations between vessel motion and ping-averaged residuals. The known limitations of that approach, however, included only being able to estimate the dominant signal, imperfectly accounting for irregular sounding distribution and it only working in shallow water. This thesis develops a rigorous inter sensor calibrator (RISC) that considers suitable local sections of swath corridor to construct a reference surface, better accounting for sounding distribution. An analytical equation based on typical integration models was designed to couple the integration errors, enabling their simultaneous estimation through optimization. Uniquely considering each depth misclosure provides a method that is equally viable in shallow and deep water conditions. This thesis proposes RISC as an automatic means of field calibration and monitoring of high frequency errors in swath systems using simulated results. 


Brandon Maingot was born and raised in Barbados, and completed a B.Sc. in Geomatics Engineering at the University of the West Indies in 2015. It was there that he was introduced to the field of hydrography among other methods of observing and processing spatial data, specializing in terrestrial observations. Brandon felt an innate attraction to the offshore aspect and was recommended to apply for the GEBCO scholarship by his professor, Dr. Miller. Brandon was part of the Year 12 GEBCO class at the Center for Coastal and Ocean Mapping, completing the program in the summer of 2016 and receiving a Cat A certificate. He then returned to UNH to pursue a master's degree in ocean engineering with an emphasis on ocean mapping. Brandon has experience with data processing and adjustment, and worked to develop these skills whilst at CCOM.