Embodiments of an arm-worn rangefinder device includes a rangefinder body and a switch. A display module that connects to the bi-stable liquid crystal display, connects to the communications cable with one or more pins, and receives the signal associated with one or more messages about the communications cable. A hash table is generated for each fingerprint segment, and an identifier for each candidate image is stored in each hash table based on the candidate image fingerprint value for the fingerprint segment associated with the hash table. All the sensors are interlinked by means of microprocessors which compare and correlate said data to automatically verify and deliver a desired wellbore diameter without the need to unnecessarily stop drilling or trip out of the hole. In order to optimise the synchronisation of the mobile terminal with the plurality of base stations, the method comprises a step of transmission of an item of information representative of a first temporal offset intended for the mobile terminal, the first offset being according to at least one reception time of the first signal by at least one base station. The invention is useful as identifying markers on articles.