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Re: ✘NTRIP and RTCM
From: |
Gary E. Miller |
Subject: |
Re: ✘NTRIP and RTCM |
Date: |
Fri, 3 Dec 2021 12:05:54 -0800 |
Yo Greg!
On Fri, 03 Dec 2021 08:53:12 -0500
Greg Troxel <gdt@lexort.com> wrote:
> That's really interesting. I am guessing:
Glad you liked it.
> RTCM2.3: these are pseudorange corrections, perhaps GPS only?
Yes, GPS only.
> RTCM3: these are carrier phase reference data, and it looks like
> your device was in FTK FLOAT
Dunno, I have not dug into the data.
> MAX: carrier phase reference data with RTK FIX
Ditto.
> > All from the Oregon ORGN network. Many thanks to them for allowing
> > me cess.
>
> Indeed, it's very nice of the states to allow public access. MassDOT
> runs MaCORS which anyone can use.
Still not as easy as many other countries.
> > a) RTCM 2.3 made the CEP(50) worse!
>
> I am fuzzy but I gather that RTCM2.3 typically is pseudorange
> corrections, and GPS only. It may be L1 only.
Yes, in this case, GPS and L1 only.
> > b) RTCM 3 was barely better than no corrections
>
> That's surpising, as for me being in RTK FLOAT is better than unaided.
It is what I have seen for years.
> Do you have SBAS disabled, so it is really "no corrections".
I do not have SBAS disabled, but that F9P rarely uses it. SNAS is
almost exactly RTCM 2.3
> Also, while I see your point about averages being not better, the
> character of the wander is very different.
Yeah. The high frequency noise is gone.
> This is what RTK FLOAT
> looks like for me (usually viewed in Vespucci in Android, which I use
> for a field data collector). RTK fixed looks like a dot.
I'll watch for that.
> > c) The synthetic corrections are just WOW.
>
> Indeed, and you can see the resolution of the coordinates which looks
> like most of 1 cm. I wonder if this quantization is in the raw logs
> or if it could be in the analysis chain.
I'm running in normal mode, with none of the "High Precision" messages.
Moany of the UBX-NAV-PVT data items are in mm. Worth a test.
> What I would find really useful is:
>
> record fix mode with each point as metadata
I have all the raw data. Nothing more can, or could, be recorded. And
it is all 3D.
> carry that through analysis and color the dots based on
> autonomous/differential/RTK-fixed/RTK-float
u-blox is bad at reporting that.
> be able to use an input position in the analysis instead of the
> average. I bet your tight value in fix is pretty much right.
Lost me. Explain?
> I am curious what antenna you are using.
The u-blox one, in a window sill.
> What I don't understand is why you aren't able to get into FIX with a
> single reference a mile away.
I don't know if I can or can't. But that is my long term experience, and
other see simiilar.
> My closest reference is much further,
> and I use "iMAX".
Do you have doc on "iMAX"?
> I am curious how many constallations ORGN is providing data for, and
> if it's MSM4 or somethihng else.
I'll look at that data next week. I captured everything. Only last
week would gpsd even log that data.
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com Tel:+1 541 382 8588
Veritas liberabit vos. -- Quid est veritas?
"If you can't measure it, you can't improve it." - Lord Kelvin
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- ✘NTRIP and RTCM, Gary E. Miller, 2021/12/02
- Re: ✘NTRIP and RTCM, Greg Troxel, 2021/12/03
- Re: ✘NTRIP and RTCM,
Gary E. Miller <=
- Re: ✘NTRIP and RTCM, Greg Troxel, 2021/12/03
- Re: ✘NTRIP and RTCM, Gary E. Miller, 2021/12/06
- Re: ✘NTRIP and RTCM, Greg Troxel, 2021/12/06
- Re: ✘NTRIP and RTCM, Gary E. Miller, 2021/12/07
- Re: ✘NTRIP and RTCM, Greg Troxel, 2021/12/08
- Re: ✘NTRIP and RTCM, Greg Troxel, 2021/12/03