Re: GPS Question
Robert G Fenske Jr (fenske@rgfpc.electro.swri.edu)
Wed, 27 Oct 1999 17:47:36 -0500 (CDT)
On Wed, 27 Oct 1999, Edward S Light wrote:
> I recall that, at least a few years ago, coordinates obtained from
> the GPS system were intentionally degraded (I believe the term was
> "SA"). If this is still true, what is the approximate magnitude of
> the effect? Centimeters? Meters? Worse? One frequently sees GPS-
That is still the case. With Selective Availability (SA), also
called the Standard Positioning Service, an ordinary user can expect 100
meter position accuracy 95% of the time. Differential GPS, a technique of
using two GPS receivers coupled with an already-known position can easily
get meter-level accuracy (as I have done with my office) and with enough
processing centimeter-level accuracy.
Robert Fenske, Jr. rfenske@swri.edu Sw |The Taming the C*sm*s series:
Southwest Research Institute /R---\ |
Signal Exploitation & Geolocation Div | I | |"The Martian canals were the
San Antonio,Texas USA ph:210-522-3931 \----/ | Martians' last ditch effort."
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