A method and device for locating an emitting source of which measurements of emission propagation at locations different from that of the emitting source can be obtained from those locations, lacking space perception, using a sensor mobile along a self-generated path. After having obtained an emission propagation measurement from the mobile sensor at the mobile sensor location, a free energy variation for moving the sensor from its current location to each of plural possible next locations of the mobile sensor is computed, the free energy being computed as a function of a standardized projected probability field of the location of the diffusing source based on previous emission propagation measurements obtained along the self-generated path. A minimum free energy variation value amongst the computed free energy variations is determined and the location associated with the determined minimum free energy variation is identified as being the next location of the sensor.