[ntp:questions] Sure gps looses all sattelite fixes

Dave Hart hart at ntp.org
Fri Feb 24 19:14:56 UTC 2012

On Fri, Feb 24, 2012 at 18:52, Chris Albertson
<albertson.chris at gmail.com> wrote:
> On Fri, Feb 24, 2012 at 10:08 AM, unruh <unruh at invalid.ca> wrote:
> ..
>> Is it evidence of some outside noise source (jamming?) , microwave tower
>> emission?
> You would need to have a second GPS receiver set up to know that.
> It's a good idea to have two, hopefully different brand receivers.

If the second GPS has a RS-232 connection you could monitor its $GPGSV
output using ntpd and see how it compares to the Sure unit at a nearby
location during the same events.

Alternatively, if you use a navigation GPS borrowed from a car which
has a satellite skyview diagram, the problem may become obvious much
more quickly.  If you're getting unlucky with all the birds in view
being blocked by obstructions during these events, the sky map of
satellite positions should make it obvious.

Good luck,
Dave Hart

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