pion:
newsflash: "Boeing airplanes using FMS as the primary means of navigation guidance have been approved by the FAA to fly GPS approaches provided an RNP of 0.3 or smaller is used.A manual entry of 0.3 RNP is requird if not automatically provided."
FCT 737 OCT31,2004
The FMS uses multiple sensors for position updating to include GPS,DME-DME,VOR-DME,LOC-GPS and IRS.It is a FAA certified RNAV equipment that provides lateral and vertical guidance referrenced from an FMS position.
About the RAIM,YUSEF is perfectly right.It's not required in this case.
Never heard of a 'RNP/ANP' approach,but I guess you're refering to RNAV approach,right?
Brgds Alex