En metode for feltkalibrering av systemparametere i et multistråleekkolodd-system

摘要

A seagoing vessel carries multibeam echo sounder transducer equipment for swath coverage of the sea floor for mapping thereof, covering a survey strip by traveling a given distance. Overlapping such strips are provided by running the vessel in opposite or crossing directions. The survey strips are transformed to a common reference system by resampling recorded reflection time measurement values to establish grid models. In order to execute field calibration of system parameters like offset in vessel roll (), pitch (omega), yaw (), vessel travel direction (x), direction (y) in horizontal plane orthogonal to said vessel travel direction, vertical depth direction (H), scale factor (my) in a swath direction, angular scale factor (m) and time delay (tau), a difference between measured survey strips and an approximation of a true sea floor relief is minimized, using the equation: X = (N1 + P2)-1 (U1 + P2L2) where formula I and X is a vector of unknown calibration parameters, A1 is a coefficient matrix, P1 is a weight matrix of the measured depth values, L1 is a vector of the differences between a mean value H*(u) and Hi(u), where formula II and n is the number of overlapping strips in grid point u and Hi(u) is the depth value of strip i in u, L2 is a vector of a priori parameter values, and P2 is a weight matrix of parameters to be computed.