Re: GPS units


sbd sbd
 

I need to test in a better way to be absolutely sure. And I will port
forward my router so people can see for themselves.
My current setup provides GPS location to any device or software capable of
receiving location and time data from a GPSD system. APRSIS32 is capable of
that.
NTP time for access from any device. Using the PPS in kernel mode rather
than user mode.
Also a samba install to allow monitoring from a windows pc.
And SNMP for remote monitoring as this is intended as a headless system.

Currently showing a bit of jitter on the GPS time as expected, but zero
jitter on the PPS.

I can create an image of the SD card. And torrent if people are interested.

Steve Daniels
Amateur Radio Callsign G6UIM
Torbay Freecycle Owner
http://uk.groups.yahoo.com/group/torbay_freecycle
APRSISCE/32 Beta tester and WIKI editor http://aprsisce.wikidot.com

-----Original Message-----
From: aprsisce@... [mailto:aprsisce@...] On Behalf
Of Gary Sanders
Sent: 27 January 2014 17:11
To: aprsisce@...
Subject: Re: [aprsisce] GPS units

Don't know if you've seen this:
http://www.talkunafraid.co.uk/2012/12/the-ntpi-accurate-time-with-a-raspberr
y-pi-and-venus638flpx/

I did similar, and never could tame the thing down - the jitter was
really bad - to the point that it really wasn't usable.

I was driving the PPS with the PPS output from a Trimble Thunderbolt
GPSDO, so I know the PPS was good. I understand that the RasPi
occasionally strips out some Oscillator clock pulses for some reason,
and I suspect that may be the cause.

More later - have to go to an appointment.

Gary Sanders
W0BY


On 1/27/2014 6:24 AM, Steve Daniels wrote:


Well I got asked to do data modes for the Olympics in Weymouth, to find
the laptop time was out enough that JT-65 did not work.

Using an adafruit breakout board GPS, that will run from 5V or 3.3V.
Enable input and fix output. Handy for balloons.

Cold starts very quickly. To the point that I have not sorted the
battery backup.

Have had it supplying APRSIS32 via GPSD with location. And time via the
normal NMEA sentences.

Got it running in user mode for NTP time easily, Which to be honest is
good enough.

But attempting to get the more accurate kernel mode working, which is
more of a problem. On my second 10 hour long compile!!

When it's working will torrent an image for everyone, as I will with an
added TNC-Pi setup using XASTIR.

I am hoping we can get APRSISMO working on the Pi. Currently there is a
graphics driver issue that stops it running. To do with 3D hardware
acceleration if I recall.

Steve Daniels



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