[LEAPSECS] GPS certified for navigation?

Steve Allen sla at ucolick.org
Thu Sep 23 15:35:02 EDT 2010


On Thu 2010-09-23T11:59:33 -0700, Robert Seaman hath writ:

> What precisely is the status of GPS for actual purposes of navigation?


You are in a twisty little maze of bureaucratic regulations, all alike.

You get what you pay for in GPS. There are significant differences in
the abilities of receivers to notice whether they are receiving
signals that are self-consistent.

In the long run, there's intentional problems like theater-level
spoofing (which the US military have used for years, as,
unfortunately, noticed by the Keck telescope control timing systems)
http://www.gpsworld.com/defense/security-surveillance/assessing-spoofing-threat-3171

For ability to notice errors see RAIM
http://en.wikipedia.org/wiki/Receiver_Autonomous_Integrity_Monitoring

For IFR aviation in the US the FAA has technical standard orders
TSO C129 (A1) and TSO C129 (A2)
describing the requirements.

for robustness against the ionosphere (mostly for surveying) see WAAS
http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System

For marine traffic in US harbors the Coast Guard requires AIS
http://en.wikipedia.org/wiki/Automatic_Identification_System

--
Steve Allen <sla at ucolick.org> WGS-84 (GPS)
UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855
University of California Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m


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