Here 3 RTK GNSS with base : Drones, UAV, OnyxStar, MikroKopter, ArduCopter, RPAS : AltiGator, drones, radio controlled aircrafts: aerial survey, inspection, video & photography
Arducopter Quickstart Guides and Tips - Arduino based Arducopter UAV, the open source multi-rotor
UBlox GPS Configuration — Copter documentation
Connecting external LED's to Arducopter | Visser I/O