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<p>Hi Kirk, thanks for your comments.</p>
<p>Note that the unit is not a Garmin.</p>
<p>My concern is not with the accuracy <i>per se</i> but the
systematic displacement of the results. GPS error is usually
"random", at least over the longer term.</p>
<p>The unit was kept static, 50-60 positions were averaged over 4+
minutes and the correction was real time SBAS. The two readings
per site were separated in time, code based only.<br>
</p>
<p>I've since deferentially corrected the file, results yet to be
reviewed.</p>
<p>In a later post, Greg refers to datum issues which I think might
be the culprit.</p>
<p>Thanks very much . . . .</p>
<pre class="moz-signature" cols="72">-----
Cheers, Spring</pre>
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<div class="moz-cite-prefix">On 06/Mar/2021 03:36, kirk wrote:<br>
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cite="mid:1615030604543.39994350034b0166@nortekresources.com">
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<div dir="auto">That is the limitation of the unit you have.
Without using differential correction or real time kinematic
techniques, that is about as good as it gets. You can improve
your position a bit by keeping the unit static and averaging the
1 hz position data for at least 2 minutes. This will give you an
average of >120 observations.. </div>
<div dir="auto">A clear view of the sky we also help improve the
accuracy. </div>
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<div dir="auto">For post processing work, you will need unit that
records raw rinex format data which ghe garmin units typically
do not.</div>
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<div dir="auto">Kirk Schmidt </div>
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<div style="font-size:85%;color:#575757" dir="auto">Sent from my
Galaxy</div>
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<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: 2021-03-06 4:35 a.m. (GMT-04:00) </div>
<div>To: qgis-user <a class="moz-txt-link-rfc2396E" href="mailto:qgis-user@lists.osgeo.org"><qgis-user@lists.osgeo.org></a> </div>
<div>Subject: [Qgis-user] Trimble GeoXT 2005 Accuracy </div>
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<p>Hello All,</p>
<p>I recently acquired a Trimble GeoXT 2005 Series and am puzzled
by the results it produces:</p>
<ol>
<li>Compared to a variety of "known" points, it consistently
records positions that appear to be in error by 1.2 - 1.5 m NW
from the known point. <br>
</li>
<li>Points are collected and then mapped in QGIS as NAD83, UTM
Zone 10 N. <br>
</li>
<li>The known points include property survey pins, Government
control survey monuments, Total Station survey points derived
from the above, other GPS results (Trimble ProXRS) and
identifiable points on orthophotos. <br>
</li>
<li>I'm using SBAS correction in the GeoXT.</li>
</ol>
<p>It appears to be adding a consistent offset to the GPS result
although no offset has been set in TerraSync.<br>
</p>
<p>Many thanks for any thoughts on this situation . . . . .<br>
</p>
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Cheers, Springfield Harrison</pre>
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