Instrument approach charts list the equipment required to fly them in their name. For this example let's say we have an ILS or LOC/DME 36R approach. This approach requires an ILS receiver for the ILS portion, or both a LOC and DME receiver for the localizer only portion.
Let's also say we're flying an airplane that has an inoperative glideslope receiver and is otherwise /G equipped with an IFR-certified and up-to-date GPS. Can the GPS be used in lieu of DME in this case?