Signal processing system and technique for calculating roll bias data

摘要

A method and apparatus for calculating roll bias data which is representative of the differences in attitude between an array of sensors of a sensing system on a vessel and an attitude sensing system on the vessel. The attitude sensing system measures the attitude of the vessel in the roll axis. The technique includes measuring first bathymetric data at a first locale at time t1 using a first beam projected at the first locale at a substantially 45 DEG angle from the vertical of the array; measuring second bathymetric data at the first locale at a time t2 using a second beam projected at substantially the same angle from the vertical of the array as the first beam from the opposite side of the vessel; and calculating roll bias data by comparing the first and second bathymetric data at the first locale. The roll bias data may be used to further calculate a roll bias correction factor. The signal processing apparatus employs the roll bias data and/or roll bias correction factor to compensate, reduce or eliminate erroneous bathymetric data caused by differences in attitude between the array of sensors of the sensing system on the vessel and the attitude sensing system.