Yeah maybe or they could have used Glonass the Russian GPS system? I think China has a system which may have been used?
But there is other lower tech which can be accurate. Photos of the facilities layout can be used to determine a grid location and height which can be programmed into targeting computers. The attackers may have used supporting ground assets with targeting lasers?
In the first Gulf war we used tourist maps to program our cruise missiles into Baghdad. Almost all our missiles followed main highways.