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<p>Hi Kirk,</p>
<p>Right, that could be the case although the GeoXT is not set up for RTCM, only WAAS. The ProXR has an RTCM antenna though. Too many variables!</p>
<p>But I see that WAAS is fairly accurate:</p>
<p>"<span style="color: rgb(32, 33, 34); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">The WAAS specification requires it to provide a position accuracy of 7.6 metres (25 ft) or less (for both lateral and vertical measurements), at least 95% of the time.</span><sup id="cite_ref-WASSspec_2-0" class="reference" style="line-height: 1; unicode-bidi: isolate; white-space: nowrap; font-weight: 400; font-style: normal; font-size: 14px; color: rgb(32, 33, 34); font-family: sans-serif; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><a href="https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System#cite_note-WASSspec-2" style="text-decoration: none; color: rgb(6, 69, 173); background: none;">[2]</a></sup><span style="color: rgb(32, 33, 34); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"><span> </span>Actual performance measurements of the system at specific locations have shown it typically provides better than 1.0 metre (3 ft 3 in) laterally and 1.5 metres (4 ft 11 in) vertically throughout most of the<span> </span></span><a href="https://en.wikipedia.org/wiki/Contiguous_United_States" title="Contiguous United States" style="text-decoration: none; color: rgb(6, 69, 173); background: none rgb(255, 255, 255); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;">contiguous United States</a><span style="color: rgb(32, 33, 34); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"><span> </span>and large parts of<span> </span></span><a href="https://en.wikipedia.org/wiki/Canada" title="Canada" style="text-decoration: none; color: rgb(6, 69, 173); background: none rgb(255, 255, 255); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;">Canada</a><span style="color: rgb(32, 33, 34); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"><span> </span>and<span> </span></span><a href="https://en.wikipedia.org/wiki/Alaska" title="Alaska" style="text-decoration: none; color: rgb(6, 69, 173); background: none rgb(255, 255, 255); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px;">Alaska</a><span style="color: rgb(32, 33, 34); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">.</span><sup id="cite_ref-WAAS_NSTB_PAN_Report_Jul06_3-0" class="reference" style="line-height: 1; unicode-bidi: isolate; white-space: nowrap; font-weight: 400; font-style: normal; font-size: 14px; color: rgb(32, 33, 34); font-family: sans-serif; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><a href="https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System#cite_note-WAAS_NSTB_PAN_Report_Jul06-3" style="text-decoration: none; color: rgb(6, 69, 173); background: none;">[3]</a></sup><span style="color: rgb(32, 33, 34); font-family: sans-serif; font-size: 17.5px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;"><span> </span>With these results, WAAS is capable of achieving the required Category I precision approach accuracy of 16 metres (52 ft) laterally and 4.0 metres (13.1 ft) vertically.</span><sup id="cite_ref-faa.gov_4-0" class="reference" style="line-height: 1; unicode-bidi: isolate; white-space: nowrap; font-weight: 400; font-style: normal; font-size: 14px; color: rgb(32, 33, 34); font-family: sans-serif; font-variant-ligatures: normal; font-variant-caps: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial;"><a href="https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System#cite_note-faa.gov-4" style="text-decoration: none; color: rgb(6, 69, 173); background: none;">[4]</a>" </sup>-Wikipedia
</p>
<pre class="moz-signature" cols="72">
-----
Cheers, Spring</pre>
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<div class="moz-cite-prefix">On 09/Mar/2021 04:32, kirk wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1615293154017.01184d3800b5ee99@nortekresources.com">
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<div dir="auto">Hi Springer</div>
<div dir="auto"><br>
</div>
<div dir="auto">I just looked up the marine beacon specs and they
are designed for 10m accuracy. This may explain why your non
dgps data is closer to your survey corner.</div>
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<div style="font-size:85%;color:#575757" dir="auto">Sent from my
Galaxy</div>
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<div dir="auto" style="font-size:100%;color:#000000" align="left">
<div>-------- Original message --------</div>
<div>From: Springfield Harrison <a class="moz-txt-link-rfc2396E" href="mailto:stellargps@gmail.com"><stellargps@gmail.com></a> </div>
<div>Date: 2021-03-08 3:17 p.m. (GMT-04:00) </div>
<div>To: Nicolas Cadieux <a class="moz-txt-link-rfc2396E" href="mailto:njacadieux.gitlab@gmail.com"><njacadieux.gitlab@gmail.com></a> </div>
<div>Cc: kirk <a class="moz-txt-link-rfc2396E" href="mailto:kirk@nortekresources.com"><kirk@nortekresources.com></a>, Jorge Gustavo
Rocha <a class="moz-txt-link-rfc2396E" href="mailto:jgr@geomaster.pt"><jgr@geomaster.pt></a>, <a class="moz-txt-link-abbreviated" href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a>,
Greg Troxel <a class="moz-txt-link-rfc2396E" href="mailto:gdt@lexort.com"><gdt@lexort.com></a>, Dan
<a class="moz-txt-link-rfc2396E" href="mailto:19dmb83@gmail.com"><19dmb83@gmail.com></a> </div>
<div>Subject: Re: [Qgis-user] Trimble GeoXT 2005 Accuracy </div>
<div><br>
</div>
</div>
<p>I'm resending this without the map as there is a size limit. The moderator may let it through, I hope . . . .</p>
<p>
</p>
<p>Hi Nicolas, thanks for your observations. I'll try to answer your questions, please see the attached map, especially Map A:</p>
<p>Note that my previous email contained information for Map B; Map A is based on the Municipal Cadastre (NAD83 UTM zone 10N) and illustrates the problem as well. Other locations based on Provincial Monuments and/or the Municipal cadastre (not illustrated here) have yielded similar results.</p>
<ol>
<li>How many “known” points have you tested?</li>
<ol>
<li>2 in this case, Maps A and B</li>
<li>Also several other locations with similar results
</li>
</ol>
<li> How where those point position calculated.</li>
<ol>
<li>From the Municipal cadastre, visible in Map A
</li>
</ol>
<li>Make sure the coordinates are in the right CRS</li>
<ol>
<li>NAD 83 UTM 10N used throught. See workflow in previous email
</li>
</ol>
<li> When converting from the monument’s CRS to NAD83 UTM zone 10N, are you using the correct grid files?</li>
<ol>
<li>[No monuments in this example] These were brought into QGIS from the Municipal GCM database CSV (NAD83(CSRS) 3.0.0.BC.1.CRD) and reprojected by QGIS to <span style="font-family:'Lato,Ubuntu,Lucida Grande,Segoe UI,Arial,sans-serif'; color:#000000;">EPSG:26910 - NAD83 / UTM zone 10N</span></li>
<li><span style="font-family:'Lato,Ubuntu,Lucida Grande,Segoe UI,Arial,sans-serif'; color:#000000;">Presumably QGIS would choose the correct grid files
</span></li>
<li>Municipal Cadastre is NAD83 UTM zone 10N<style type="text/css">p, li { white-space: pre-wrap; }</style></li>
</ol>
<li>Find a geodesic point that is in the middle of a field or on the side of a highway with no obstacles.</li>
<ol>
<li>Map A is open sky
</li>
</ol>
<li>Make sur your observations will be done when the constellation is well distributed in the sky</li>
<ol>
<li>As you probably know, TerraSync provides for PDOP, HDOP, SNR and Horizon masks to preclude collecting poor quality positions. These were set towards the "Precision" end of the scale
</li>
</ol>
<li>What post processing techniques are you using? How far is the base station from your unit?</li>
<ol>
<li>Real time was SBAS or RTCM; Post processing using the Pathfinder Office differential correction engine, baseline about 30 km
</li>
</ol>
<li>How long are the observations? Have you tried other methods of post processing like PPP?
</li>
<ol>
<li>Logging interval is 5 sec; 33 to 2037 positions per point</li>
<li>Did not use PPP. This is a test of mapping best practices, not geodesy
</li>
</ol>
<li>Have you contacted Trimble?
</li>
<ol>
<li>Yes, no response
</li>
</ol>
<li>Have you looked on there site to see if there is a software update (firmware) for the unit or the post processing software?</li>
<ol>
<li>Yes, receiver firmware is the latest, PFO and Terrasync are older but compatible
</li>
</ol>
</ol>
<p>Thanks Nicolas. If I have missed something, I hope someone can point it out, I've tried to cover all the bases based on my training and experience.</p>
<pre cols="72" class="moz-signature">-----
Cheers, Spring</pre>
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<div class="moz-cite-prefix">On 08/Mar/2021 06:40, Nicolas Cadieux
wrote:<br>
</div>
<blockquote type="cite"> Hi Harrison,
<div><br>
</div>
<div>How many “known” points have you tested? How where those
point position calculated. They could be off. If you are
using state geodesic monuments, try to find the documented
precision of the monument. States have different types of
monuments, some are very old and have different standards.
Make sure the geodesic point is not the problem. Make sure
the coordinates are in the right CRS. As an example, if the
coordinates are published in NAD83 original but you are
assuming NAD83(CSRS), then you have a problem. When converting
from the monument’s CRS to NAD83 UTM zone 10N, are you using
the correct grid files? What is the published precision for
this reprojection?</div>
<div><br>
</div>
<div>You say you have houses and trees. This could be the
problem. Find a geodesic point that is in the middle of a
field or on the side of a highway with no obstacles. Make sur
your observations will be done when the constellation is well
distributed in the sky. I believe Trimble has a observation
planing software that can help you figure out the best time
for observation. This could explain why the GEoTX are to the
east unless the observations where made at the same time and
same conditions (ex leaf off).</div>
<div><br>
</div>
<div>What post processing techniques are you using? How far is
the base station from your unit? If you are using a state
correction service, can you select more stations? How long
are the observations? Have you tried other methods of post
processing like PPP? </div>
<div><br>
</div>
<div>Have you contacted Trimble? Have you looked on there site
to see if there is a software update (firmware) for the unit
or the post processing software? </div>
<div><br>
</div>
<div><br>
</div>
<div>
<div dir="ltr">Nicolas Cadieux
<div><a href="https://gitlab.com/njacadieux"
moz-do-not-send="true">https://gitlab.com/njacadieux</a></div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">Le 8 mars 2021 à 05:24, Springfield
Harrison <a href="mailto:stellargps@gmail.com"
class="moz-txt-link-rfc2396E" moz-do-not-send="true"><stellargps@gmail.com></a>
a écrit :<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<p>Hi Kirk,</p>
<p>Thanks again for the ideas.</p>
<p>Re "I assume your raw data files are being converted to gpx on a
computer since the raw terrasync files are proprietary binary
files". Not sure why you would make this assumption - PFO does
not export GPX files, only GIS files of many kinds, although one
could create a custom format I suppose.</p>
<p>I have always avoided non-GIS formats (Garmin, GPX, GDB, KML,
KMZ, GoogleEarth, iPad/Tablet "mapping", etc.). I'm in the
process of re-mapping a tablet based tree inventory using SW Maps
with a Total Station survey as many of the trees are near the
property boundary. Some of the tablet errors are quite large.
Due to the tree canopy, GPS quality is variable.</p>
<p>I know that many people use tablets and hiking GPS as mapping
tools but I have little faith in them for that purpose.
</p>
<p>For many years my work flow has been: Trimble Receiver +
RTCM/SBAS -> Pathfinder Office [+ RINEX Post Processing] ->
SHP files -> GIS (QGIS or Manifold GIS). The CRS is NAD83 UTM
10N throughout, for my home area at least.
</p>
<p>None of these steps offer any option to choose or modify the Base
Station CRS so I don't think that would be the culprit in my NW
data offset, although maybe I've missed something.</p>
<p>Last fall I collected quite a few points in an attempt to
quantify the problem, if that's what it is. Here are some
summaries:</p>
<p> </p>
<table width="445" cellspacing="0" cellpadding="0"
border="0">
<colgroup><col
style="mso-width-source:userset;mso-width-alt:4242;width:87pt"
width="116"> <col
style="mso-width-source:userset;mso-width-alt:3510;width:72pt"
width="96"> <col
style="mso-width-source:userset;mso-width-alt:2742;
width:56pt" width="75" span="2"> <col
style="mso-width-source:userset;mso-width-alt:3035;width:62pt"
width="83"> </colgroup><tbody>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt;width:87pt" width="116"
height="17"><b>Average distance from "Known" point
(m)</b><br>
</td>
<td style="width:72pt" width="96"><br>
</td>
<td style="width:56pt" width="75">Location</td>
<td style="width:56pt" width="75"><br>
</td>
<td style="width:62pt" width="83"><br>
</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl30" height="17"
align="center"><b>Receiver</b></td>
<td class="xl31" align="center"><b>Correction</b></td>
<td class="xl46" align="center"><b>Corner</b></td>
<td class="xl47" align="center"><b>IP NW</b></td>
<td class="xl34" align="center"><b>Grand Total</b></td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl26" height="17">GeoXT</td>
<td class="xl24">Post</td>
<td class="xl35" align="right">1.44</td>
<td class="xl36" align="right"> </td>
<td class="xl42" align="right">1.44</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl27" height="17"> </td>
<td class="xl25">SBAS</td>
<td class="xl37" align="right">1.37</td>
<td class="xl38" align="right">1.26</td>
<td class="xl43" align="right">1.33</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl27" height="17"> </td>
<td class="xl25">Uncorr</td>
<td class="xl37" align="right">0.73</td>
<td class="xl38" align="right"><br>
</td>
<td class="xl43" align="right">0.73</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl28" height="17">GeoXT
Total</td>
<td class="xl29"> </td>
<td class="xl39" align="right"><b>1.34</b></td>
<td class="xl39" align="right"><b>1.26</b></td>
<td class="xl44" align="right"><b>1.32</b></td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl26" height="17">ProXR</td>
<td class="xl24">RTCM</td>
<td class="xl35" align="right">0.38</td>
<td class="xl36" align="right">0.61</td>
<td class="xl42" align="right">0.49</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl28" height="17">ProXR
Total</td>
<td class="xl29"> </td>
<td class="xl39" align="right"><b>0.38</b></td>
<td class="xl39" align="right"><b>0.61</b></td>
<td class="xl44" align="right"><b>0.49</b></td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl32" height="17">Grand
Total</td>
<td class="xl33"> </td>
<td class="xl40" align="right"><b>1.17</b></td>
<td class="xl41" align="right"><b>0.97</b></td>
<td class="xl45" align="right"><b>1.12</b></td>
</tr>
</tbody>
</table>
<p>
</p>
<p> </p>
<table width="739" height="293" cellspacing="0"
cellpadding="0" border="0">
<colgroup><col
style="mso-width-source:userset;mso-width-alt:4242;width:87pt"
width="116"> <col
style="mso-width-source:userset;mso-width-alt:3510;width:72pt"
width="96"> <col
style="mso-width-source:userset;mso-width-alt:2742;
width:56pt" width="75" span="2"> <col
style="mso-width-source:userset;mso-width-alt:3035;width:62pt"
width="83"> <col
style="mso-width-source:userset;mso-width-alt:4644;width:95pt"
width="127"> <col
style="mso-width-source:userset;mso-width-alt:5741;width:118pt"
width="157"> <col
style="mso-width-source:userset;mso-width-alt:5339;width:110pt"
width="146"> </colgroup><tbody>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt;width:87pt" width="116"
height="17"><br>
</td>
<td style="width:72pt" width="96"><br>
</td>
<td style="width:56pt" width="75">Location</td>
<td style="width:56pt" width="75">Data</td>
<td style="width:62pt" width="83"><br>
</td>
<td style="width:95pt" width="127"><br>
</td>
<td style="width:118pt" width="157"><br>
</td>
<td style="width:110pt" width="146"><br>
</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" height="17"><b>Count of
Feature Points and Positions</b><br>
</td>
<td><br>
</td>
<td class="xl28">Corner</td>
<td class="xl29"> </td>
<td class="xl28">IP NW</td>
<td class="xl29"> </td>
<td class="xl48">Total Count of Point_ID</td>
<td style="border-left:none" class="xl48">Total Sum
of Filt_Pos</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl32" height="17"
align="center"><b>Receiver</b></td>
<td class="xl33" align="center"><b>Correction</b></td>
<td class="xl50" align="center"><b>Count of Point_ID</b></td>
<td class="xl51" align="center"><b>Filt_Pos</b></td>
<td class="xl50" align="center"><b>Count of Point_ID</b></td>
<td class="xl51" align="center"><b>Filt_Pos</b></td>
<td class="xl49" align="center"><b> </b></td>
<td style="border-left:none" class="xl49"
align="center"><b> </b></td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl26" height="17">GeoXT</td>
<td class="xl24">Post</td>
<td class="xl36" align="right">9</td>
<td class="xl37" align="right">1492</td>
<td class="xl36" align="right"> </td>
<td class="xl37" align="right"> </td>
<td class="xl38" align="right">9</td>
<td style="border-left:none" class="xl38"
align="right">1492</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl27" height="17"> </td>
<td class="xl25">SBAS</td>
<td class="xl39" align="right">8</td>
<td class="xl40" align="right">1280</td>
<td class="xl39" align="right">5</td>
<td class="xl40" align="right">905</td>
<td class="xl41" align="right">13</td>
<td style="border-left:none" class="xl41"
align="right">2185</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl27" height="17"> </td>
<td class="xl25">Uncorr</td>
<td class="xl39" align="right">2</td>
<td class="xl40" align="right">2836</td>
<td class="xl39" align="right"> </td>
<td class="xl40" align="right"><br>
</td>
<td class="xl41" align="right">2</td>
<td style="border-left:none" class="xl41"
align="right">2836</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl30" height="17">GeoXT
Total</td>
<td class="xl31"> </td>
<td class="xl42" align="right"><b>19</b></td>
<td class="xl43" align="right"><b>5608</b></td>
<td class="xl43" align="right"><b>5</b></td>
<td class="xl43" align="right"><b>905</b></td>
<td class="xl44" align="right"><b>24</b></td>
<td style="border-left:none" class="xl44"
align="right"><b>6513</b></td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl26" height="17">ProXR</td>
<td class="xl24">RTCM</td>
<td class="xl36" align="right">4</td>
<td class="xl37" align="right">2541</td>
<td class="xl36" align="right">4</td>
<td class="xl37" align="right">683</td>
<td class="xl38" align="right">8</td>
<td style="border-left:none" class="xl38"
align="right">3224</td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl30" height="17">ProXR
Total</td>
<td class="xl31"> </td>
<td class="xl42" align="right"><b>4</b></td>
<td class="xl43" align="right"><b>2541</b></td>
<td class="xl43" align="right"><b>4</b></td>
<td class="xl43" align="right"><b>683</b></td>
<td class="xl44" align="right"><b>8</b></td>
<td style="border-left:none" class="xl44"
align="right"><b>3224</b></td>
</tr>
<tr style="height:12.75pt" height="17">
<td style="height:12.75pt" class="xl34" height="17">Grand
Total</td>
<td class="xl35"> </td>
<td class="xl45" align="right"><b>23</b></td>
<td class="xl46" align="right"><b>8149</b></td>
<td class="xl45" align="right"><b>9</b></td>
<td class="xl46" align="right"><b>1588</b></td>
<td class="xl47" align="right"><b>32</b></td>
<td style="border-left:none" class="xl47"
align="right"><b>9737</b></td>
</tr>
</tbody>
</table>
<p>
</p>
<p>Corrected test Points and separation from the antenna location.
</p>
<div><malbiblkchcpcpdh.png></div>
<p>
</p>
<p>As above but with 2 uncorrected GeoXT points overlaid, including
the individual positions that were averaged.
</p>
<div><jpbjaanipeilbbgo.png></div>
<p>Notes and findings:</p>
<ol>
<li>Site is open sky but with house and trees adjacent</li>
<li>Antenna is static, occupation periods long (5 sec logging
interval)</li>
<li>32 observations averaged from 9737 positions</li>
<li>some observations are with the GeoXT internal antenna, others
are with a Trimble aircraft antenna (intended for SBAS)
</li>
<li>Work flow as outlined above</li>
<li>The GeoXT uncorrected results are better than either of the
corrected results!?</li>
<li>The corrected ProXR results are better than any of the GeoXT
results, although biased to the east</li>
<li>The uncorrected GeoXT readings exhibit the NW bias but to a
lesser extent which seems to indicate that the correction does
not create the problem but may exacerbate it, if that makes any
sense.</li>
<li>I have probably missed something but my reaction remains that
the receiver may be defective (?)
</li>
</ol>
<p>Thanks again for your help and patience . . . . .
</p>
<pre cols="72" class="moz-signature">-----
Cheers, Spring</pre>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 07/Mar/2021 03:54, kirk
wrote:<br>
</div>
<blockquote type="cite">
<div dir="auto">Hi Springer.</div>
<div dir="auto"><br>
</div>
<div dir="auto">I assume your raw data files are being
converted to gpx on a computer since the raw
terrasync files are proprietary binary files. If you
are using trimble pathfinder, you can post process
differentialy correct the data if you have access to
base station logged at the same time you captured your
field data. Having a base station 100 miles away will
not improve your results as the baseline is too long.</div>
<div dir="auto"><br>
</div>
<div dir="auto">I do not know if you can write a gpx
file directly from pathfinder but I would not bother.
I would write a shapefile which will contain the
coordinate system you specify. Simply open in qgis
and you should be good to go. If your older unit works
better, I would expect it may be an issue with the
setup within pathfinder or perhaps the software
version.</div>
<div dir="auto"><br>
</div>
<div dir="auto">I think your consistent offset is a
direct result of how you are converting your data from
trimble to gpx.</div>
<div dir="auto"><br>
</div>
<div dir="auto">As I mentioned in my previous comments,
there are many issues which affect accuracy. Just
because the box says it is accurate you will rarely
replicate that in the field. </div>
<div dir="auto"><br>
</div>
<div dir="auto">In terms of WAAS dataframes, these are
processed internally on your field unit.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Kirk Schmidt </div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto" id="composer_signature">
<div dir="auto" style="font-size:85%;color:#575757">Sent
from my Galaxy</div>
</div>
<div dir="auto"><br>
</div>
<div><br>
</div>
<div style="font-size:100%;color:#000000" dir="auto"
align="left">
<div>-------- Original message --------</div>
<div>From: Springfield Harrison <a
href="mailto:stellargps@gmail.com"
class="moz-txt-link-rfc2396E"
moz-do-not-send="true"><stellargps@gmail.com></a>
</div>
<div>Date: 2021-03-07 5:57 a.m. (GMT-04:00) </div>
<div>To: kirk <a
href="mailto:kirk@nortekresources.com"
class="moz-txt-link-rfc2396E"
moz-do-not-send="true"><kirk@nortekresources.com></a>,
Jorge Gustavo Rocha <a
href="mailto:jgr@geomaster.pt"
class="moz-txt-link-rfc2396E"
moz-do-not-send="true"><jgr@geomaster.pt></a>,
<a href="mailto:qgis-user@lists.osgeo.org"
class="moz-txt-link-abbreviated"
moz-do-not-send="true">qgis-user@lists.osgeo.org</a>,
Greg Troxel <a href="mailto:gdt@lexort.com"
class="moz-txt-link-rfc2396E"
moz-do-not-send="true"><gdt@lexort.com></a>,
Dan <a href="mailto:19dmb83@gmail.com"
class="moz-txt-link-rfc2396E"
moz-do-not-send="true"><19dmb83@gmail.com></a>,
Nicolas Cadieux <a
href="mailto:njacadieux.gitlab@gmail.com"
class="moz-txt-link-rfc2396E"
moz-do-not-send="true"><njacadieux.gitlab@gmail.com></a>
</div>
<div>Subject: Re: [Qgis-user] Trimble GeoXT 2005
Accuracy </div>
<div><br>
</div>
</div>
<p>Hello All,
Thanks for the comments, I'll reply more fully tomorrow.
The receiver is Trimble mapping grade:
"The GeoExplorer 2005 series consists of:
• The GeoXH™ handheld, providing subfoot (30 cm) accuracy, or
even 8-inch (20 cm) accuracy
with the optional Zephyr™ antenna.
• The GeoXT™ handheld offering submeter accuracy for GIS data
collection and data
maintenance.
• The GeoXM™ handheld with 1–3 meter GPS accuracy for mobile GIS
applications."
"Post processed carrier accuracy: 1-30cm". This receiver was
probably $5-8000 (?) new.
</p>
<ul>
<li>Data collection was stationary, open sky, good satellite
coverage, several minutes of 5 sec observations, good PDOP</li>
<li>SBAS and/or post processed
</li>
</ul>
<p>The concern is not the accuracy as such, but the systematic NW
shift. This has been observed over several months,
consistently. My old Trimble ProXR (1994?, $20K new!) is
actually better in this regard than the GeoXT!
The Trimble manuals make no mention of the SBAS CRS, implying
"turn it on and go, the receiver will integrate the SBAS into
the rover file."
More tomorrow, thanks . . . . .
</p>
<pre class="moz-signature" cols="72">-----
Cheers, Spring</pre>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 06/Mar/2021 15:56, kirk
wrote:<br>
</div>
<blockquote type="cite">
<div dir="auto">A few notes.</div>
<div dir="auto"><br>
</div>
<div dir="auto">sbas which is waas in north America is
based on equatorial satellites which will get you in
the 1 m range in southern Canada. </div>
<div dir="auto"><br>
</div>
<div dir="auto">you can achieve sub decimeter accuracy
consistently using rtk ,either through a ntrip
caster (base station) broadcasting over the intenet
or with your own base station and a radio link.
there are a few chip sets and break out boards that
you acquire and assemble your own system. This is a
very inexpensive option.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Another option in Canada is to use
precise point positioning (PPP) which requires 6 to
12 hours of observation data using L1, L2 or L1 and
L2 data and rinex log files. This comes in handy if
you need to establish a remote base station.</div>
<div dir="auto"><br>
</div>
<div dir="auto">A proper antennae with a metal ground
plane is also critical to getting quality results.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Observing under a forested canopy is
difficult especially in summer under leaf on
conditions, after a rain which creates multiparth
mayhem.</div>
<div dir="auto"><br>
</div>
<div dir="auto">There is a reason survey grade
equipment is relatively expensive. If you require
repeatably accurate results in a variety of
conditions this is an option.</div>
<div dir="auto"><br>
</div>
<div dir="auto">Kirk Schmidt </div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div id="composer_signature" dir="auto">
<div style="font-size:85%;color:#575757" dir="auto">Sent
from my Galaxy</div>
</div>
<div dir="auto"><br>
</div>
<div><br>
</div>
<div dir="auto" style="font-size:100%;color:#000000"
align="left">
<div>-------- Original message --------</div>
<div>From: Jorge Gustavo Rocha <a
class="moz-txt-link-rfc2396E"
href="mailto:jgr@geomaster.pt"
moz-do-not-send="true"><jgr@geomaster.pt></a>
</div>
<div>Date: 2021-03-06 6:41 p.m. (GMT-04:00) </div>
<div>To: <a class="moz-txt-link-abbreviated"
href="mailto:qgis-user@lists.osgeo.org"
moz-do-not-send="true">qgis-user@lists.osgeo.org</a>
</div>
<div>Subject: Re: [Qgis-user] Trimble GeoXT 2005
Accuracy </div>
<div><br>
</div>
</div>
<p>Hi,</p>
<p>I just jump in this thread to say I'm really impressed with
Ardusimple. I have a RTK Handheld Surveyor Kit [1] for +- 400
€ and it works really well.</p>
<p>I use the national NTRIP service and I have consistently
precisions around 10 cm with just one receiver.
</p>
<p>I use a free Android application called SW Maps [2]. My
survey points, tracks and photos are collect in a geopackage
that I can read in QGIS. I use it mostly to collect ground
control points for my drone flights.
</p>
<p>Regards,</p>
<p>Jorge Gustavo
</p>
<p>[1] <a href="https://www.ardusimple.com/product/rtk-handheld-surveyor-kit/" class="moz-txt-link-freetext" moz-do-not-send="true">https://www.ardusimple.com/product/rtk-handheld-surveyor-kit/</a></p>
<p>[2] <a href="https://play.google.com/store/apps/details?id=np.com.softwel.swmaps" class="moz-txt-link-freetext" moz-do-not-send="true">https://play.google.com/store/apps/details?id=np.com.softwel.swmaps</a></p>
<div class="moz-cite-prefix">Às 20:12 de 06/03/21,
Greg Troxel escreveu:<br>
</div>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Springfield Harrison <a href="mailto:stellargps@gmail.com" class="moz-txt-link-rfc2396E" moz-do-not-send="true"><stellargps@gmail.com></a> writes:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Thanks Dan. See my relies to Kirk and Greg. The Emlid sounds
interesting, will have a look.
</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">I have an earlier Emlid Reach (not RS or RS2), which has L1 only, and I
never got it to work well.
Also look at the Ardusimple unit -- but it's more a parts kit than a
system. You need a way to get RTK reference data in, and a good
antenna. One approach is Vespucci (OSM editor for Android) as a
datalogger, and the Ardusimple WiFi NTRIP master to get corrections over
the phone's hotspot.
<a href="https://www.ardusimple.com/product/simplertk2b/" class="moz-txt-link-freetext" moz-do-not-send="true">https://www.ardusimple.com/product/simplertk2b/</a>
</pre>
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