I had a question for the GPS archaeologists they might be able to answer. Just before President Clinton left office he passed a law which removed the "scrambled" signal applied by the US Defense Department to GPS satellite transmissions, purportedly, so that missile silos could not be targeted accurately, with most GPS receivers.
Does anyone know if that "option" as I understand it (once turned off in the early 1990s for "Desert Storm" and many veterans mother bought GPS to send off with their now veteran I read) has been reintroduced now that (gee I thought of this now?) the US Congress declared "War on Terrorism"? In government one of the first accurate uses with setup differential transmitters was in the Bay of Fundy, New Brunswick, Canada, with the highest tides in the world so that fishing boats, ferries, etc., had more accurate locations in a pretty regularly foggy environment.
Have the Iranians one set of calculations and the British Navy another set?
Answer: (from histarch forum online)
No, it has not been reintroduced. Selective availability was turned off in 2000. The military has developed and continues to develop better and more secure ways of positional accuracy without the need for SA.