Maximum likelihood estimator based on Quality Factor for bathymetric multibeam echosounder

For modern multibeam echosounders, the use of a robust and reliable quality estimator associated with each sounding is an absolute necessity. Indeed, due to the large volume of data acquired, a lot of time is lost, both during the survey and the post-processing. This is a costly problem for hydrographers. The definition of a quality estimator based on the characteristics of the beamformed signal gives an answer to this problem. It has been successfully implemented by several sonar manufacturers and its relevance in measuring the quality of each sounding has been demonstrated. Based on the Quality Factor and on the existing way of processing a sounding, we defined a new sounding estimator using a maximum likelihood approach. This new approach was developped under several hypothesis which are plausible under certain conditions. This new estimator was successfully tested and implemented on real data with good results.