Abstract: The present invention relates to a process for compensating the magnetic disturbances influencing the measurements of a device for determining the magnetic heading, mounted on a land vehicle or aircraft, comprising a magnetometer furnishing analog voltages proportional to the components of the disturbed magnetic field of the earth along its reference axes. It is admitted that the locus of the end of the vector indicative of the field is an ellipse for a land vehicle and an ellipsoid for an aircraft, of which identification from the analog voltages and transformation into a circle or sphere centered at O, origin of the axes of the magnetometer, enable correction coefficients to be calculated which are introduced into the memory of a computer unit associated with the magnetometer in order to define at any instant a vector making with a reference axis of the magnetometer an angle corresponding to the real magnetic heading of the vehicle or of the aircraft.