Again, coupled with differential corrections (available for free over radio) the resulting precision was in centimeter range. The reason it wasn't used was the physical size and cost (for hand-held navigation) and the lack of supporting hardware in cars (no user-facing on-board systems with screens and UI).
SA was _not_ the reason for the lack of consumer-level GPS adoption.
In my experience using DGPS around 2000, most of the DGPS sources were near the coasts and operated by the Coast Guard. There were a few scattered transmitters here and there, certainly not enough to provide the kind of coverage we now enjoy.
Again, coupled with differential corrections (available for free over radio) the resulting precision was in centimeter range. The reason it wasn't used was the physical size and cost (for hand-held navigation) and the lack of supporting hardware in cars (no user-facing on-board systems with screens and UI).
SA was _not_ the reason for the lack of consumer-level GPS adoption.