In message <[EMAIL PROTECTED]> Nate Williams writes:
: > : You may not know the answer to this, but it's worth a shot. Wht kind of
: > : accuracy can we expect using 'cheap' off-the-shelf GPS receivers?
: >
: > We're getting, with ntp4 on a 3.x kernel, about +- 4uSec with a cheap
: > gps receiver + atomic clock on a i486 class machine.
:
: I've got the cheap gps receiver (Garmin 12XL), but what do you mean by
: an 'atomic clock'? Should the GPS receiver's NMEA messages be adequate
: enough to do the job? However, all I need is ms accuracy, so anything
: below 500us is good enough for me.
We have a cesium clock, which is generally called atomic clock, that
we use for various things in our system. If the GPS gives out a PPS
signal for the NMEA, then you can likely hit 1mS w/o any problems at
all. Don't know a thing about the Garmin 12XL to know for sure about
how it operates.
Warner
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