Re: gpsd hardware with RTK support?

[Greg Troxel]

"Gary E. Miller" <gem@rellim.com> writes:

>> MaCORS can send on various mountpoints (for carrier phase, omitting
>> CMR):
>> 
>>   RTCM 3.x (Extended) : GPS/GLO only
>>   RTCM 3.x (MSM4)     : GPS/GLO/GAL/BDS including GPS L5
>
> Only MSM4?  Sad.

I have not found info that really makes the case that MSM7 is better in
practice.

>>  I am using MaCORS which is
>> Leica and I go into FIX very easily (given good sky view) and have
>> observed 4 cm repeatability when occupying the same mark days later.
>
> 4cm not that great these days.

For F9P, $100-class antenna and RTK where the reference receivers are in
the 25 km range, vs 500m, I think it is.  People quote theoretical
accuracies all the time, and I'm talking about actually making repeat
measurements on a real mark with some tree cover.  At this degree of
accuracy you need to be careful about leveling; I was hand-holding a
prism pole with a bubble level.

I would be very interested to see similar data from others, doing:

  establish some point that you can return to

  measure it with RTK (and a prism pole or tripod) once, with a 30s
  average, and compute the mean with qgis etc.
  
  several days later, do it again, wait a few more days, do it a third
  time

  talk about the extreme spread of the 3 measurements, longest side of
  the triangle.  Explain the RTK reference source, leveling method, and
  antenna.

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