<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:large">If you don't want to attempt to engineer your own GNSS hardware + software, you may want to check out the Bad Elf GNSS Surveyor. Yes, it's in the neighborhood of $500 US, but gives relatively consistent positions within about 1 meter with averaging, its data can be differentially corrected using the RTKLIB open-source software, and if you are working in an area with cell service, it can receive real-time corrections via NTRIP networks if this is available in your area (it is here in Michigan). Some Googling will turn up tutorials. I have done some simple comparisons with Trimble hardware and have been pleased with the results.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:large"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:large">Best,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:large">Mike</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, May 23, 2020 at 3:45 PM <<a href="mailto:j.huber@post-ist-da.de">j.huber@post-ist-da.de</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<div>Hi Nicolas,</div>
<div><br>
</div>
<div>there are several potentially accurate
GNSS modules available, even sensitive choke ring antennas aren't
that expensive. What's time consuming and difficult is building a
whole functioning system (integration and software).<br>
</div>
<div>This would be a great university
project - develop an open source GNSS system based on relatively
unexpensive components. It should be possible to get the cost down
from over a thousand to several hundred euro. This could also be
the basis for a "free" correction data service built on private
reference stations. Just dreaming...</div>
<div><br>
</div>
<div>I agree that for precision, "old
school" technology is often better and cheaper, although it
requires more effort than simply pushing a button.<br>
</div>
<div><br>
</div>
<div>Regards<br>
Jochen<br>
</div>
<div><br>
</div>
<div>Am 23.05.20 um 20:21 schrieb Nicolas
Cadieux:<br>
</div>
<blockquote type="cite">
<div>Hi,</div>
<div><br>
</div>
<div>I looked at the page.It looks like a neat project! Buy time
you buy a case, antenna... (I don’t think they come with on),
your back into the price range of a forestry grade survey GPS
unit. I think the Emild single band gps (<a href="https://emlid.com/reachrs/" target="_blank">https://emlid.com/reachrs/ </a>) is
probably a better choice unless you really want to make this a
learning project. But if I understand you are really on a shoe
string budget.</div>
<div><br>
</div>
<div>None of these Gps, by the way, would beat and old
theodolite... if you can establish or find a good gps position
(look for the city or state geomatics services) or survey point,
a théodolite would give you survey grade positions. City have
these points on every few blocks. You may be able to find A
theodolite for free. A second hand TotalStation could be better
but that will be more difficult to find in those price ranges
(Shoe string). You can also rent equipment or find a college
that would take this up as a teaching opportunity.</div>
<div><br>
</div>
<div>Have fun!</div>
<div><br>
<div dir="ltr">Nicolas Cadieux
<div>Ça va bien aller!</div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">Le 23 mai 2020 à 13:52, Bernd
Vogelgesang <a href="mailto:bernd.vogelgesang@gmx.de" target="_blank"><bernd.vogelgesang@gmx.de></a> a écrit :<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">
<p>Unfortunately, the Forest Service Website went offline
(maybe this thread caused so much traffic that it broke
down? ;) )<br>
</p>
<p>I'm also desperately searching for an affordable way to
have at least some decent accuracy. I do not need
submeter, but it would be fantastic if it was possible to
achieve meter accuracy.<br>
I gave up on that Garmin stuff. They might be accurate,
but I have no chance to control this until I return home
and put the recorded data on screen over an aerial image.
Those screens are a joke, and the business logic that
prevents me to put reasonable aerial imagery on the device
without paying a fortune is apita. Maybe this improved
cause I last checked 5 years ago.</p>
<p>Mobile phones at least in my case seem to get worse. My
Motorola from 2016 had an accuracy of less than 4 meters,
most of the time less than 2.<br>
Now I bought a Huawei 30 pro cause of the camera (my first
phone with nice pictures!), but the accuracy is a
nightmare. The position is jumping around like a dog on
rabies.<br>
I also bought a bluetooth device (Navilock BT-821G) two
years ago. This is much better than the phones GPS, tho it
only receives 20 satellites maximum (The phone claims to
receive some 40). But also this device sometimes, when
walking a transect, is constantly 5 meters off the track
for several several minutes.</p>
<p>As apps averaging the positions were mentioned: Does
anyone have a recommendation on such apps (for Android)? I
found some, but the usability was not that great, and some
even didn't enhance anything.</p>
<p>Furthermore, I stumble upon an article about a module
with u-blox chip. <a href="https://www.sparkfun.com/products/16481" target="_blank">https://www.sparkfun.com/products/16481</a><br>
Does anyone have any experience with modules like this and
what else is needed? The description of all the stuff
leaves me a bit puzzled.</p>
<p>Cheers,</p>
<p>Bernd<br>
</p>
<div>On 23.05.20 18:17, Michael.Dodd
wrote:<br>
</div>
<blockquote type="cite">
<div> <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.2041-210X.2011.00118.x" id="gmail-m_-4099059542455145880LPlnk857492" target="_blank">https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.2041-210X.2011.00118.x</a>
I did this quite a few years ago but in the graph in
supplimentary material it shows how the accuracy of one
consumer grade gps varies over time (at a fixed point).
At the time I also did a lot more measurements using
mobile phones and consumer grade units on a grid of
points in the field, that was not published but
basically the phones were often as good as if not better
than the consumer grade gps units especially when using
certain apps to average points.<br>
</div>
<div id="gmail-m_-4099059542455145880LPBorder_GTaHR0cHM6Ly9iZXNqb3VybmFscy5vbmxpbmVsaWJyYXJ5LndpbGV5LmNvbS9kb2kvZnVsbC8xMC4xMTExL2ouMjA0MS0yMTBYLjIwMTEuMDAxMTgueA..">
<table id="gmail-m_-4099059542455145880LPContainer618713">
<tbody>
<tr>
<td>
<div id="gmail-m_-4099059542455145880LPImageContainer618713"> <a id="gmail-m_-4099059542455145880LPImageAnchor618713" href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.2041-210X.2011.00118.x" target="_blank"><img id="gmail-m_-4099059542455145880LPThumbnailImageId618713" alt="" width="123" height="160"></a></div>
</td>
<td>
<div id="gmail-m_-4099059542455145880LPTitle618713"> <a id="gmail-m_-4099059542455145880LPUrlAnchor618713" href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.2041-210X.2011.00118.x" target="_blank">Where are my
quadrats? Positional accuracy in fieldwork -
Dodd - 2011 - Methods in Ecology and
Evolution - Wiley Online Library</a></div>
<div id="gmail-m_-4099059542455145880LPDescription618713"> Introduction.
There has been much written about sampling
design, spatial scale and the need for
permanent plots in ecological long‐term
monitoring, for example, the paper on spatial
scaling in ecology has been cited over 1500
times, but one frequently ignored issue,
intimately associated with sampling design,
scale and permanence of plots, is how to
locate positions accurately.</div>
<div id="gmail-m_-4099059542455145880LPMetadata618713">
<a href="http://besjournals.onlinelibrary.wiley.com" target="_blank">besjournals.onlinelibrary.wiley.com</a></div>
</td>
</tr>
</tbody>
</table>
</div>
<br>
<hr>
<div id="gmail-m_-4099059542455145880divRplyFwdMsg" dir="ltr"><b>From:</b> Qgis-user <a href="mailto:qgis-user-bounces@lists.osgeo.org" target="_blank"><qgis-user-bounces@lists.osgeo.org></a>
on behalf of Nicolas Cadieux <a href="mailto:nicolas.cadieux@archeotec.ca" target="_blank"><nicolas.cadieux@archeotec.ca></a><br>
<b>Sent:</b> 23 May 2020 16:34<br>
<b>To:</b> Randal Hale <a href="mailto:rjhale@northrivergeographic.com" target="_blank"><rjhale@northrivergeographic.com></a><br>
<b>Cc:</b> <a href="mailto:qgis-user@lists.osgeo.org" target="_blank">qgis-user@lists.osgeo.org</a> <a href="mailto:qgis-user@lists.osgeo.org" target="_blank"><qgis-user@lists.osgeo.org></a><br>
<b>Subject:</b> Re: [Qgis-user] wishing for accurate
lattitude/longitude from a cell phone
<div> </div>
</div>
<div><span>
<div>CAUTION: This mail comes from
outside the University. Please consider this before
opening attachments, clicking links, or acting on
the content.<br>
<br>
Hi,<br>
<br>
This is a very interesting list. It basically
confirms what I thought. Consumer Point and shoot
deceives are all around 2-6m with no canopy. The
average multiple positions basically give you a
better idea as a gps may get lucky. It would be
nice to have the full methodology for this and more
data (like the number of satellite and the position
of the constellation and the gps price list) but
it’s very interesting none the less. I was also
happy that the data confirms the precision of the
gps Sx-Blue 11. This claims to be sub meter and my
tests indicated that on our office unit but it’s
nice to see it done elsewhere. For about 2000$,
this gps is pretty good. As for the rest, the
difference between 150$ and 1000$ is probably more
a function of the options (like maps and screen
size...) and not a question of precision. It would
be nice to know what gps chips they are running...<br>
<br>
Interesting thing also is that based on my reviewing
the data on my phone (without graph or cross
tabulation tables) is that the Glonas Constellation
does not seem to help much. Quick stats on this
list would confirm this. Maybe this is just a
figment of my imagination because there’s only so
much information you can grad without running proper
stats.<br>
<br>
Thanks for the post.<br>
<br>
Nicolas Cadieux<br>
Ça va bien aller!<br>
<br>
> Le 23 mai 2020 à 09:02, Randal Hale <a href="mailto:rjhale@northrivergeographic.com" target="_blank"><rjhale@northrivergeographic.com></a>
a écrit :<br>
><br>
> One other thing that may or may not be of use
but the USDA Forest Service Publishes a GPS Receiver
Report that covers phones - and that's helped if
I've had a client go "Well I have a Apple
<something> or a Android <thing>". At
least I feel slightly better going "good enough" or
"no not good enough".<br>
><br>
> It should be good worldwide (but I will admit I
think phones are my 'tech ceiling' these days) but
your mileage may vary.<br>
><br>
> <a href="https://www.fs.fed.us/database/gps/mtdcrept/accuracy/index.htm" target="_blank">https://www.fs.fed.us/database/gps/mtdcrept/accuracy/index.htm</a><br>
><br>
> Randy<br>
><br>
>> On 5/22/20 8:55 PM, Priv.-Doz. Dr. Maria
Shinoto wrote:<br>
>> Somehow I did not follow the discussion,
but like to add some of our experience.<br>
>><br>
>> We are doing field work in a remote region
in the southern Japanese mountains, archaeological
surveys on the ground based on LiDAR data.<br>
>><br>
>> A simple Garmin etrex10 is mostly reliable
in an area of 40cm by 40cm around a measured point,
if used repeatedly at this point and the point is
located in the middle of a valley. Even cell phones
do a good enough job. As soon as we get closer to
the steep slopes, the accuracy of the Garmin is less
than 5 to 10 meters. We can check this with the
detailed LiDAR based map, and geologists told us,
that even an expensive device could not be more
precise under these conditions. So we decided to
measure traditionally on the ground if precise
measure is necessary, otherwise note the GPS data
and the location as shown in the map.<br>
>><br>
>> To sum up, we came to the conclusion not to
spend money on an expensive GPS that may not work in
the shadow of steep slopes -- or in the streets of
New York. -- I appreciate any additional advice, and
hope that this experience can save Steve's
organisation some money...<br>
>><br>
>> Best,<br>
>> Maria<br>
>><br>
>><br>
>><br>
>>>> Am 23.05.2020 um 03:54 schrieb
Stephen Sacks <a href="mailto:sacks44@earthlink.net" target="_blank"><sacks44@earthlink.net></a>:<br>
>>><br>
>>> In order to make widely available some
wise advice, I'm sending to this list a message I
received from Neil B. In addition to Neil's message
below, I want to mention that Nicolas Cadieux also
provided similar information, saying I'd have to pay
around $1,000 for equipment that gives consistently
accurate location coordinates. And thanks, also to
Falk Huettmann and Bernd Vogelgesang for their
replies.<br>
>>><br>
>>><br>
>>> Message from Neil B:<br>
>>><br>
>>> Hello Stephen.<br>
>>> Glad that you're having su<br>
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