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Re: Recommend a USB gps for Rpi
From: |
David J Taylor |
Subject: |
Re: Recommend a USB gps for Rpi |
Date: |
Sat, 10 Oct 2020 07:55:11 +0100 |
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
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
Re: Recommend a USB gps for Rpi, Greg Troxel, 2020/10/10