The Search Persists for GPS Backup
A June editorial in GPS World magazine notes that ICAO’s marine equivalent, the International Maritime Organization (IMO), has endorsed eLoran as the backup to GPS. This echoed the unanimous view of GPS industry leaders, who advocate eLoran as the best solution for all users. FAA and White House bureaucrats, however, decided against eLoran last year, apparently ignoring GPS experts and successful eLoran flight tests by the FAA Technical Center, as well as dismissing notions of embedding miniature eLoran chip backups in airborne GPS receivers to automatically take over–with RNP 0.3 accuracy, no less. Ironically, as the IMO presented its report, the U.S. Coast Guard was busy dismantling the nation’s loran/eLoran stations, worsening the IMO’s fear of another Exxon Valdez, or a cruise ship accident, during a GPS outage. The FAA plans a three-day meeting next month to examine GPS backup candidates, with inertial and multitracking DME strong contenders. However, neither appears to meet the cost and low-level coverage needs of non-airline aviation, or the terrestrial mobile and fixed infrastructure communities.