[ntp:questions] Sure Electronics GPS board: Amazing performance. :-)

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Fri Apr 1 06:03:31 UTC 2011

Chris Albertson wrote:
> On Thu, Mar 31, 2011 at 8:19 AM, unruh<unruh at wormhole.physics.ubc.ca>  wrote:
>> 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.
> I'd have to say the Motorola Oncore UT+ is the easiest to use.  All
> the connections are to  0.1" pitch male header pins so there is no
> need for solder.  The UT+ sells for about $16 on ebay.  The
> documentation is exhaustive and complete and written in "standard
> English".   And of course the UT is very accurate with a standard
> deviation in the PPS of about 49 nS.
> The newest version of this GPS is the M12M sold by Synergy Systems.
> It sells in qty 1 for $60 and comes with tech support from a US
> company and has PPS arcuate at the 2nS level.   I'll buy this one next
>   I don't think the dps18 comes even close to 2ns.

I don't think any GPS comes even close to 2 ns, given that the entire 
GPS constellation is only required to be within 14 ns or so of UTC.

(Yes, I know that GPS currently performs significantly better than the 
original targets of max ~10ns between GPS time and UTC, and the sat 
clocks are also better, but 2 ns is still national timing lab territory 

> Here is the data sheet.
> http://www.synergy-gps.com/images/stories/pdf/m12mt_brochure.pdf

- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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