Disclosed is a method for measuring an external parameter by atomic interferometry, using two sets of atoms that belong to different species. Two measurements are taken simultaneously at the same location, but independently from one another, in order to obtain two measurement results. One of these measurement results removes an indeterminacy among several possible values of the external parameter, by taking into account only the other measurement result. A method of this kind can be used to measure a coordinate of a gravitational field or a coordinate of an acceleration of the atoms.