judgecorp writes "The European Union has successfully tested eLoran, a land-based system to be used as a backup for satellite GPS. As shipping and other transport rely more heavily on GPS, a backup is needed, since cheap GPS jammers are emerging. They are currrently used by moonlighting truck drivers, but could be used by terrorists in future.
The proposed backup system, eLoran, uses long-wave radio, and is based on the now-obsolete US LORAN (long range navigation) system, which in turn was developed from RAF technology used in World War II."
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