A fast algorithm for the computation of induced geomagnetic field in the oceans using remote reference signals

The geomagnetic primary field external to the Earth induces a secondary field inside the Earth´s crust and oceans. Using a remote reference located on shore for convenience, and precalculated transfer functions, the authors show that the time dependant electromagnetic field at any location is a linear combination of space only functions multiplied by time functions. This separation between space and time functions is the basis for a fast algorithm to compute the time dependant electromagnetic field at any location