[ntp:questions] Sure Electronics GPS board: Amazing performance. :-)
unruh at wormhole.physics.ubc.ca
Thu Mar 31 15:19:27 UTC 2011
On 2011-03-31, Uwe Klein <uwe_klein_habertwedt at t-online.de> wrote:
> David J Taylor wrote:
>> I would be most interested in a copy of the programming manual should
>> you get one.
> Just got my two samples. nice. works out of the box.
> The pcb design is rather well done imho.
Well, no they do not work out of the box for timing purposes. One has to
solder on some wires (If you serial port responds to 3V pulses, you can
just go directly from the PPS output port to the DCD pin on the serial
plug, or you can go to http://www.leapsecond.com/pages/MG1613S/ for
instructions on how to get serial port voltages out by soldering to
three of the surface mount pins on the board-- requires a stead hand, a
very fine soldering iron, and very fine solder (or better pretinning and
a quick heatup).
My only concern is that the unit places its location 12m away from its
actual location on Googleearth-- ie, either googleearth is 12 m out in
its alignment to lat/long grid at my house, or the unit is misreporting
its position. Note that the scatter has only a standard deviation of
about 1.5 m ( coming from its use of WAAS I suspect), so it is not that
that 12 m is just part of the natural variation in gps.
(Does anyone know of anywhere where the alignment errors of google earth to the
grid is discussed?)
A brief 10 min test at a survey marker put the unit about 3 m away from
that marker on googleearth-- but that was at a location 6km from my
That leapsecond web page complained about the quality of the soldering
on the board (dirty solder joints, messy solder joints) but my board did
not have any of those problems.
> Rather interesting to follow the GSV sentences
> ( sat number, direction and quality )
> All Docs are per download:
Unfortunately none of the docs I have found discuss the upload commands
format or type for this chipset. Ie, it tells you of the nmea sentences
it emits, but not how to change which sentences it emits. Those GSV
sentences are interesting for a few minutes, but they also do bury the
relevant timing sentences in a bunch of other junk (for timing
For general useage, the garmin 18 is still probably the easiest bet.
While it does require soldering on power (eg usb) and a serial port,
that soldering is relatively easy to do, and the documentation on the
gps18 is far superior. It is about twice the price.
(And that blue LED on the Sure board really is bright. In a dark room,
it lights up the walls of the room every time it comes on).
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