CORS ? Continuously Operating Reference Stations

CORS — Continuously Oper­ating Reference Stations — offers GPS guidance featuring RTK-level accuracy that can be received through cellular networks using cell modems or cell phones. CORS networks generally originate from a state-level department, most often transportation, for use in surveying and construction. But states are rapidly making these networks available to the private sector upon request. So far there has been no subscription fee attached to use of the networks.