Greetings
I know that the accuracy of GPS degrades indoors. However, suppose
that I just want to turn a GPS module on, acquire the current time
accurate to a second, and then turn it off. I can get a good deal on
the U-Blox LEA-5H modules (same as used on Arduino shields I think),
which have a high sensitivity, and I can use an active antenna if
needed.
Am I wasting my time. Sorry for not requiring the time more accurate
than a second, but that's all the clients require.
Tom Harris
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Tom,
If the GPS has a battery backup, then you might get re-acquisition within
less than 30 seconds of powering up. That's approximate with a u-blox
NEO-6M on the top floor of a two-storey building, about 1/3 the way into the
room, so most of the signal is through the roof.
Without battery backup, the acquisition time might be a lot longer (15-20
minutes), or even worse (hours) with a different GPS module which needs a
much stronger signal to acquire than to track. The one which took hours had
a 15 mm square patch antenna (AdaFruit), versus the 25 mm square antenna on
the u-blox board I had.
The two units I am comparing are shown on my Web page here:
http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html
although it's down right now. I quite accpet that other folks may have
different results (or if "indoors" is next to a window!).
Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
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