In message:
"Lux, James P" writes:
:
:
:
: On 5/19/09 1:15 PM, "Russell Rezaian" wrote:
:
: > At 12:58 PM -0700 2009/05/19, Hal Murray wrote:
: >> USB has a bad reputation, but I think it's way way overblown. Yes, it's
: >> polled, but that polling is done in hardware and the ti
On 5/19/09 1:15 PM, "Russell Rezaian" wrote:
> At 12:58 PM -0700 2009/05/19, Hal Murray wrote:
>> USB has a bad reputation, but I think it's way way overblown. Yes, it's
>> polled, but that polling is done in hardware and the time scale is 1 ms. If
>> you are satisfied with an accuracy of a
At 12:58 PM -0700 2009/05/19, Hal Murray wrote:
USB has a bad reputation, but I think it's way way overblown. Yes, it's
polled, but that polling is done in hardware and the time scale is 1 ms. If
you are satisfied with an accuracy of a few 10s of ms, USB works fine. The
problem is the GPS unit
li...@philpem.me.uk said:
> All of which are running the SiRF 3.2 firmware, so if there is a
> firmware bug in play, they're all going to be doing much the same
> thing...
I'm pretty sure that all the SiRF units I was watching had essentially the
same behavior, and that included one using RS-2
Hal Murray wrote:
I started collecting low cost GPS receivers a year or two ago. I thought I
had some with the SiRF-II chips. Either I can't find them or I didn't
actually get any.
I've been "collecting" the OEM modules for about the same amount of time. That
said, I haven't got that many -
li...@philpem.me.uk said:
>>> Interesting that the three receivers with issues were all SiRF III
>>> based. Do you know what firmware these were running?
>> Nope. If you know the recipe to find out, I'll ask them. :)
> Failing that, the "sirfmon" app that comes with gpsd might get the
> re
Hal Murray wrote:
Interesting that the three receivers with issues were all SiRF III
based. Do you know what firmware these were running?
Nope. If you know the recipe to find out, I'll ask them. :)
I just scanned their NMEA documentation and didn't see any way to get it.
If memory serves
li...@philpem.me.uk said:
> Interesting that the three receivers with issues were all SiRF III
> based. Do you know what firmware these were running?
Nope. If you know the recipe to find out, I'll ask them. :)
I just scanned their NMEA documentation and didn't see any way to get it.
> How
Hal Murray wrote:
One case was a gross software bug. I think it was triggered by a pending
leap second.
http://www.megapathdsl.net/~hmurray/ntp/leap-gps.gif
Interesting that the three receivers with issues were all SiRF III based. Do
you know what firmware these were running?
How are you
Geoff,
I'm not in a position to check at present, but have also noticed
discrepancies in the time pips in the past. I'd not use a GPS receiver
for this, as they can easily indicate a second or so out. I use a GPS
Disciplined Receiver (HP Z3801A or Trimble NTGS50AA) for the job.
I suggest you talk
> I am assuming my GPS clocks I have are correct (too early here to get
> WWVH reception).
> Hoping the one second delta is not me!
I have seen consumer grade GPS receivers be off by a second while claiming to
be OK.
One case was a gross software bug. I think it was triggered by a pending
Att NZ Time nuts:
Normally National Radio (AM and FM) is a reasonable source of time in
New Zealand, and the time pips are normally within about 200 ms of UTC
atomic time (due to coding delays in the digital transfer of the audio
program).
However today at 11am and Noon (local time 18 May 2009) I
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