Complex sentence: The ATV's rendezvous and docking system mounted a telegoniometer, which functioned as a radar system, and two videometers, which fired laser pulses at cube-shaped reflectors on the ISS' "Zvezda" service module for range detection.
Split into simpler sentences: The ATV's rendezvous and docking system mounted a telegoniometer, which functioned as a radar system. Also on board were two videometers, which fired laser pulses at cube-shaped reflectors on the ISS' "Zvezda" Service Module for range detection.