Computation of calibration parameters for multibeam echo sounders using the least squares method

A new method for field calibration of multibeam echo sounders is presented. The method applies least-squares adjustment computation of static offsets in parameters such as roll, pitch, heading and the horizontal shift of the transducer relative to the reference point of the positioning system. All the parameters are derived simultaneously. An investigation demonstrates the precision and the flexibility of the method. Flexibility is here related to the design of calibration lines, i.e., their number, their direction and length. The strength of the method is its ability to utilize all the depth measurements in an optimal way. The variance of the parameters can be derived directly from least-squares adjustment, but limited knowledge of the stochastic properties of the observations can lead to optimistic precision estimates. An alternative method to compute quality estimates is proposed and demonstrated.