Hi Paul,
I noticed the module you mentioned uses the Sirf III chipset. I've been
doing a good bit of experimentation with a GlobalSat BU-353 (no PPS)
which is also based on the same chipset. David Taylor was nice enough
to post my experience on his website from a series of dialogs we had.
You might find the information useful, including how I programmed the
unit. The GlobalSat specific data may not apply to the unit you
mentioned, but the Sirf stuff should apply to either. If you want to
look it up, the link is below. I don't think that page mentions it, but
I now have my unit outputting only the GPZDA NMEA sentence, which seems
to give the most accurate timing information and the least jitter. I
don't think this sentence has any position information. Obviously, with
PPS, the accuracy of the NMEA is less important. But, with my current
setup, I'm getting pretty consistent +/- 6 ms accuracy.
http://www.satsignal.eu/ntp/conversation-with-ron.html
Sincerely,
Ron
On 2/12/2012 9:31 PM, Paul J R wrote:
Figure I might chime in with the gps unit I got and if your in Aust i
think its probably about the best deals i've seen that has a pps line
(theres also another one they have if you can do smd soldering thats
cheaper again).
http://www.twig.com.au/store/product_info.php?products_id=108&osCsid=148a3e8759d5ae6b8ab6f3f0489e0fd4
<http://www.twig.com.au/store/product_info.php?products_id=108&osCsid=148a3e8759d5ae6b8ab6f3f0489e0fd4>
I was looking to put together the dirt-cheapest ntpd machine with pps i
could, and that was the cheapest i could find (though i havent had the
time to put mine together as yet because the pps line does need some
soldering). I also happened to have a wyse terminal (x86 based)
http://www.wyse.com/products/hardware/thinclients/S10/index.asp that i
picked up for around 30$ (currently running ubuntu 10.10 server without
too much drama).
On 13/02/12 13:00, Dave Hart wrote:
On Sat, Feb 11, 2012 at 10:20, Terje Mathisen wrote:
unruh wrote:
GEt the manual from Mediatex MTK NMEA Packet User Manual, which gives a
far far more extensive set of nmea programming instructions for the
chipset that Sure uses.
Does that one have more info than my current program?
C:\c2\nmea-mtk>Release\nmea-mtk.exe -?
nmea-mtk (c) 2011 Terje Mathisen
Syntax: nmea-mtk [options]
The SURE electronics unit people have been buying as an affordable
refclock for those with soldering skills and time is the reference
design for the SkyNet SKG16AH chip known as SKG16B [1]. Unruh and
Terje are talking about a MTK (I or II?) chipset. Does anyone know
the relationship between the two? I'm wondering if there's a way to
refer to both unambiguously, or if they're subtly different beasts.
After a little more digging I came across a nice comparison table of
chipsets [2] which suggests to me the SKG16AH is derived from or
clones the interface of a MTk design. If you have additional insight
or can correct me, I'd appreciate it.
[1] http://www.skylab.com.cn/datasheet/SkyNav_SKG16AH_DS.pdf
[2] http://wiki.openstreetmap.org/wiki/GPS_Chipset
Cheers,
Dave Hart
--
(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such. I don't always see new messages very quickly. If you need a
reply and have not heard from me in 1 - 2 weeks, send your message again.)
Ron Frazier
timekeepingdude AT c3energy.com
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