I am seeing the same thing -- big jumps every single time a satellite is
counted or not. Elevation mask 10 degrees, which should be very good
and stable for my location. The unit also insists on converging to a
bat altitude, then after a while declares stored position bad . .. then
declares position good, even with bad altitude.
Ideas appreciated.
jimwb4...@amsat.org
On 8/1/2013 6:31 AM, Bob Camp wrote:
Hi
You may have your elevation mask set to low for your antenna or a multi path
issue from some other source. If the survey location is good to under a meter
and the signals are good, there should be very little shift as sats are picked
up or dropped.
Bob
On Aug 1, 2013, at 5:09 AM, gandal...@aol.com wrote:
Hi Charles
Thanks for your comments, the surveyed position on this is looking pretty
good but what I have now realised is that the severity of the jumps seems
very much related to the number of sattelites being tracked.
Switching from 8 to 7, or 7 to 8, sats seems to produce the biggest step
change whilst switching in either direction between 5 and 6, for example,
doesn't seem to show up at all on the monitored DAC voltage.
Ok, I take that back, it does still seem to depend on the number of sats
being switched between but I've just seen a switch from 5 to 4 sats induce a
very noticeable step change in DAC voltage, so the relationship doesn't
appear to be linear.
Unfortunately I need to power this down now for a few days but will
investigate more later.
Regards
Nigel
GM8PZR
In a message dated 01/08/2013 09:45:24 GMT Daylight Time,
charles_steinm...@lavabit.com writes:
Nigel wrote:
at times I'm seeing very noticeable step changes in the DAC voltage
on this one as that happens.
* * *
I am a bit surprised by the extent, a Mark Sims online plot from
2012 shows some correlation on an NTGS50AA but not as noticeable as
this, and I don't recall seeing anything quite so pronounced on a
Thunderbolt.
IME (with TBolts), the magnitude of the DAC steps with constellation
changes varies with the accuracy of the positional data used by the
GPS. To a point, the more accurate the survey, the smaller the DAC
jumps will be. (Other errors prevent reducing the
constellation-change DAC steps to zero.)
Mark has commented here on survey accuracy, and the methods he used
in Lady Heather to maximize it.
Best regards,
Charles
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
