Re: Recommend a USB gps for Rpi

[David J Taylor]

Can anyone on the list recommend a USB gps for the Raspberry Pi? My use case 
is for it to provide time services to a cluster so it doesn’t have to be 
super accurate. I currently have a u-blox 8 which works with gpsd but the 
time from it jumps all over the place.

I am aware of the Adafruit Ultimate gps hat which is a bit pricey. It would 
need an external antenna as the Pi’s themselves don’t have clear access to 
the sky. My current one is in a skylight with a short USB extension lead to 
reach. The Adafruit hat costs $100 and another $30 for the antenna in 
Australia.

Thanks in advance.

MarkJ
==================================

Mark,

I can recommend the Uputronics HAT:

 
https://store.uputronics.com/index.php?route=product/product&path=60_64&product_id=81

It can provide the PPS required for precision timing, and works well with 
the "$10" GPS puck antennas.

If your u-blox 8 isn't a fake (I've had Chinese ones which are fakes, 6 or 7 
remarked) there shouldn't be jumps.  Is the antenna well positioned?  How 
many satellites are used?  Any GPS jammer parked outside?  I use puck 
antennas on a magnetic sheet just near a south-facing window and get 
excellent results:

 http://www.satsignal.eu/ntp/2019-01-08-1330-23b-GPS-antenna-farm.jpg
from:
 http://www.satsignal.eu/ntp/

If the number of satellites is marginal, you could try ensuring that as many 
constellations as possible are active.  It might help.  GPS, GLONASS and 
Galileo work well together.  Typically I see 35 satellites and use 19, this 
on an indoor puck antenna on the second floor of a two-storey house.

 http://www.satsignal.eu/mrtg/raspi22-gps.html

Cheers,
David
--
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Email: david-taylor@blueyonder.co.uk
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