Videometer

A videometer is a European designed automatic docking system that guides an Automated Transfer Vehicle (ATV) towards the docking port of the Russian Zvezda Service Module of the International Space Station (ISS). The ATV uses relative global positioning system (GPS) in order to close in on the ISS up to a distance of 249 m. Thereafter the ATV uses two videometers, together with additional data from telegoniometers, to automatically complete the docking maneuver. Both videometers are active during rendezvous with one acting as a back-up.