Vectorial magnetic field of a vessel from the vertical field

The easiest and cheapest way to get the magnetic field of a vessel is to measure the vertical component of the field while the vessel moves over an array of vertical magnetic sensors located in a horizontal line (perpendicular to the bow-stern direction) at a particular depth. In order to obtain the vectorial field of the vessel (three-component field) the author has used a mathematical technique based on potential theory, applying it to the data of the vertical field. The technique is easily implemented as software for a microcomputer. It has the advantage of producing exact results (it is not a mathematical model) in a few seconds of processing time, processes data that can be measured by a small number of magnetometers and produces data for any location and oriented in any spatial direction