Abstract: Data on influencing signatures of world-wide sea mine models is collected on board a host sea vessel and undergoes periodic updating to maintain accuracy of the display on vessel vulnerability to such sea mines, obtained on-board from such collected data, measurements of current status conditions of the host vessel and calculation therefrom of surface actuation onsets with respect to each of the sea mine models.

Abstract: An eddy current magnetic field effects measurement apparatus employs, a reference sensor located so that it measures an applied field and any environmental fields but does not measure eddy current effects. Then an estimate(s) of the applied field at the locus of a plurality of measurement sensors is constructed and stored. Next, a conductive object or material to be measured is placed in the applied field in the vicinity of the plurality of measurement sensors away from the reference sensor and measurements are made of the applied field, any environmental fields and any fields due to the effects of eddy currents induced into the conductive object or material. Finally, the aforementioned stored estimate(s) are used to compensate the applied field at the locus of the plurality of measurement sensors so that the eddy current magnetic field effects due to the placement of the conductive object or material can be observed on a keyboard/display or printed via a printer/plotter.