RES155 – 243 – ANNEX 1 TO RESOLUTION 155 (WRC-15) UAS CNPC links FIGURE 1 Elements of UAS architecture using the FSS Ann1-resol_ 155-01 4 UACS Remote pilot UACS Earth station (fixed on the ground)BLOS LOS LOS radio line-of-sight BLOS beyond LOS UAS CNPC links 1 + 2: Forward link (remote pilot to UA)1: Forward uplink (E-s)2: Forward downlink (s-E)3 + 4: Return link (UA to remote pilot)3: Return uplink (E-s)4: Return downlink (s-E)Geostationary-satellite orbit VHF - AM UA ES ATC 2 1 3 FSS space station