Hi Springer.Have fun and your questions stimulated a good discussion and
ideas.If you are collecting gps data on the clock, I would seriously consider
installing a ground plane on your range pole. This will eliminate zingers and
you can reduce your observation time. A electrical junction box cover works
well.Waas currently is good to 0.9 m horizontal and 1.3 m vertical 95% of the
time. It helps but is not a stand alone solution for high precision work.Kirk
SchmidtSent from my Galaxy
-------- Original message --------From: Springfield Harrison
<[email protected]> Date: 2021-03-10 4:30 a.m. (GMT-04:00) To: Kirk
Schmidt <[email protected]>, [email protected] Subject: Re:
[Qgis-user] Trimble GeoXT 2005 Accuracy Hi Kirk,OK, I'll rule out the PPP for
now, although it doesn't seem to be practical for production mapping anyway.I
think my antennas are probably OK, none of them have a ground plane, not
practical for field mapping. I've only seen them in geodetic applications. Of
course, the aircraft installation is free of multipath except while on the
ground. Longer observing periods should minimize the impact of multipath
zingers.The tight clustering of the GeoXT points in Map A doesn't smell of
multipath to me.Earlier you noted the possibility of antenna shielding by the
operator. With that in mind, I use a tripod or a range pole with the antenna
above head height. WAAS is actually quite accurate, good for certain (lower
order?) precision approaches.I'm still digesting all this helpful feedback and
will work on a summary shortly. Thanks again . . . .-----Cheers, SpringOn
09/Mar/2021 12:14, Kirk Schmidt wrote:> Hi Springfield:>> PPP requires long
observation times in the order of hours and > therefore a new field survey. I
would try post processing from a high > precision site with your existing
data.>> Another issue may be the aviation antennae you mentioned. These are >
usually mounted on the top of a fuselage and therefore the aluminum > acts as a
ground plane to effectively filter out multipath. If you > use a metal disk or
plate and a ground plane on your antennae and > mount it on a tripod, you may
find you end up with better results. > You will notice survey grade antennae's
have a large diameter plastic > case since the contain an internal 10 cm metal
disk.>> Kirk Schmidt>> On 3/9/2021 1:36 PM, Springfield Harrison wrote:>> Hello
Garth,>>>> Thanks very much for that reference. I have used the service in the
>> past.>>>> I'm in the middle of other work but may try to re-process some Map
A >> files using PPP to see what changes.>>>> Your work sounds more like
surveying than mapping, interesting.>>>> I do use the GPS reception planning
tools but SV availability is >> certainly better than in the early days.>>>>
Thanks again . . . .>>>> ----->> Cheers, Spring>>>>>>>> On 09/Mar/2021 09:01,
Garth Fletcher wrote:>>> Nicolas Cadieux wrote:>>>> Kirk could be on the right
track. You could try PPP using this >>>> site. You will need to create a user
name and password. Then, you >>>> upload the Rinex file. I am 99% sure you can
process point from >>>> outside of Canada. >>>>>> I routinely use CSRS PPP to
post process RINEX files from Southern New>>> Hampshire (43°N, 72°W).>>>>>>
Using an iGage iG3s (L1/L2 dual frequency, GPS + GLONASS) recording at>>> 5
second epochs in forested areas, from post processing I get>>> 30 minute
recordings, 95% error ellipses < 1 meter>>> 10 hour recordings, 95% error
ellipses < 2 cm>>>>>> CSRS-PPP site is>>>
<https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php?locale=en>>>> enter
your email address>>> select Static and which NAD 83 epoch you want, or ITRF>>>
Submit a RINEX file (.zip compressing the file is encouraged)>>> they will
email back a detailed report>>>>>> You can submit for 1 of 3 levels of post
processing>>> ultra-rapid : submit > 90 minutes after end of recording>>>
rapid: submit > 24 hours after end of recording>>> final: submit ~ 3 weeks
after end of recording>>>>>> Major part of corrections are in ultra-rapid, the
higher levels provide>>> further refinements.>>>>>>>>> FYI: Trimble provides
occupation planning aids at>>> <https://www.gnssplanning.com/#/charts>>>> just
enter your location and date and it shows you the DOP as>>> a function of the
hour of day.>>>>>> Cordially,>>
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