Tall guy...152,
My understanding is that the GPS receivers now in use will work OK (could be wrong tho...
) but will need software changes for the vertical profile.
Personally have done over 85 GPS approaches in the last seven years with my private aircraft (TSO equipment required of course) and have found them
all to be very accurate.
WAAS will be available over the entire USA, LAAS only available at select locations.
Still VOR/ILS/DME remains for the foreseeable future...even Loran C is not to be switched off for sometime...and remains very accurate also. Sadly, my Loran just died and went to avionics heaven
, so will just purchase another serviceable unit.