Autoland is not even possible at this time in the real realm. However the approach minimums are getting lower and lower. The required accuracy is achieved via a recomputation of the GPS signal for the approach. An airport stationary reciever station can take out the random uncertainty intentionally introduced by the military which normally degrades the accuracy for civilian users. Using the difference between it's known position and the recieved position, it can re-transmit a corrected signal.
Such technology is possible, but the world of commercial aviation adapts slowly and with conservitism for reasons of reliability and backwards compatability.
Cheers: t.