A method is provided for determining a coupling between magnetometers of an array of N magnetometers, for example with optical pumping, where each magnetometer includes a field cancellation system capable of being activated to operate the magnetometer in zero field. This method includes a first phase during which one of the N magnetometers is a measuring magnetometer whose field cancellation system is activated and the other N-1 magnetometers have their field cancellation system deactivated. This first phase includes generation by the magnetometers, of a plurality of reference magnetic fields of known amplitudes and distinct directions, the measurement, by the measuring magnetometer, of the ambient magnetic field on a plurality of measurement axes, and determination of coupling coefficients between the measuring magnetometer and each of the N magnetometers from said measurement and said known amplitudes.