In the U.S., the Nationwide Differential GPS system is a major example (see NDGPS). See GPS, LORAN, Galileo and Selective Availability.

Brilliant moron uses empty snack bags to block his employer’s GPS tracking, gets fired anyway By Mike Wehner Published Nov 30th, 2017 7:32PM EST ...

TYSONS CORNER, VA, Dec. 13, 2016 ” Lockheed Martin (NYSE: LMT) will update the U.S. Air Force ‘s GPS satellite ground control system to support GPS Block III satellite operations as part of ...