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Re: GPS suppression



>NORAD is not releasing the 2 line elements for the GPS constellation, 
>that is true. The other message was an April Fool's joke, pointing out 
>how ludicrous this truth is. Every GPS satellite continously broadcasts 
>its own exact position, as well as orbital elements and status 
>information for the rest of the constellation. This information is 

I've been archiving the broadcast orbital elements (known as almanacs
and ephemerides) as received on my GPS receiver since October
1997. The data is in an extended keplerian format, as the two-line
element data is not accurate enough even for 100 meter navigation. The
extended format includes various curve-fitting "fudge factors" that
provide much better accuracy over short (4 hour) intervals, plus
information on the spacecraft clock that is also needed for the
navigation solution.

If NORAD is not releasing 2-line elements for GPS, it could be simply
because there's no demand for them, because much better elements are
already available in real time from the satellites themselves. And
post-processed high accuracy ephemerides are available online from
several websites.

Phil


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