ON THE ESTIMATION OF STANDARD DEVIATIONS IN MULTIBEAM SOUNDINGS

This paper describes a simple and robust method of estimating the stan dard deviation of multibeam soundings. As an illustration of the metho d, upper and lower estimates of the standard deviations for the angula r sector. 0 to 60 degrees of the BCC (ELAC's BOTTOMCHART COMPACT SHALL OW WATER) and RESON's SeaBat-9001 system are calculated at various dep ths. Furthermore, the accuracy of the method is discussed, together wi th the case where the variation of the sea bed inside the footprint of the transducer beams cannot be ignored, the case in point being measu rement of the size of a field stone situated at a depth of 22 metres.