The present invention relates to a system for locating a mobile element, characterized in that it comprises: at least one beacon emitting radio messages; at least one relay capable of emitting a second message with a known lag following the receipt of a first message originating from said at least one beacon; at least one sensor capable of measuring in a local time base the instants of arrival of the messages originating from said at least one beacon and at least one relay; at least one position computer, that can be central or onboard each sensor, capable of determining the position of a mobile element on the basis of the arrival time information; the mobile element being able to be a beacon, a relay or a sensor.