For a start, your airline has to be cleared to do the approaches (as mine is) and then almost certainly the crews have to have some training in GPS approaches.
Then, for the approach this is what we require (Airbus):
Two operable FMGCs
GPS Primary displayed on both MCDUs.
GPS 1 and 2 in NAV mode (Checked on theGPS Monitor Page)
RNP 0.3 (0.37 prior to the IF)
WRTo Failures after the IF:
With GPS Primary lost on one side - Use the other AP/FD.
GPS Primary lost on both sides - Go around.
FM/GPS POS DISAGREE message - Go around.