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<div class="moz-cite-prefix">Dear Antonio, that's a great
experiment....I'll be glad to get my hands on a L1+L2 20 Hz
receiver some day....your results are far from a small progress,
IMHO. :-)<br>
<br>
How is turning out the comparison? how similar are both results
for the same data?. It would be excellent that RTKLIB/RTKPOST
could be validated with that level of data and experiments against
those "well known top-level proffesional" (and very expensive)
closed software suites, at least for some level of performance or
for some defined applications.<br>
<br>
Regarding the wireless testing, at our lab we have some "in the
field" experience in data links on 400, 900 and 2400 Mhz (WiFi),
so feel free to ask if you ever need some advice.<br>
<br>
The theoretical concepts behind GNSS positioning are like diving:
the deeper you go, the darker it gets, especially if the
electromagnetic signals, carrier modulations, pseudorandom Gold
codes correlation and phase shifts by the Doppler effect aren't on
your everyday range of worries....(neither did I recalled all this
stuff when I went diving on GNSS positioning trying to understand
it, and as an electronic engineering student all those concepts
should be "natural" for me, supposedly :-)....eventually I did
decipher most of the "magic" behind this system, but when I got to
face ambiguity resolution I just gave up....I'm hoping to find
time again to dive THAT deep.....but now if the results are good
enough to challenge commercial well known top level
software-hardware, I'll be focusing on applications for it!<br>
<br>
Best regards, thanks for that fast and complete answer, and good
luck on your experiments.<br>
<br>
<pre class="moz-signature" cols="72">Mauro Ugarte A.
Ingeniero de Desarrollo
División de Instrumentación Óptica y Tecnologías de Teledetección
Centro de Óptica y Fotónica
Universidad de Concepción
F/Fax: 2204740 | <a class="moz-txt-link-abbreviated" href="mailto:mauro.ugarte@cefop.udec.cl">mauro.ugarte@cefop.udec.cl</a>
</pre>
<br>
On 29/06/12 13:09, António Pestana wrote:<br>
</div>
<blockquote
cite="mid:CACHwcgJuEYWq1rT02tNhkGC5XuK1gzqjLENBPnNnfTZFf4jzcA@mail.gmail.com"
type="cite">Dear Mauro
<div><br>
</div>
<div>Sorry from my very long silence.<br>
<div><br>
</div>
<div>I'm still testing the use of RTKLIB/RTKPOST to simulate
"real-time" kinematic positioning in structural monitoring.
I'm afraid my progress is still small. </div>
<div><br>
</div>
<div>We have done some experiments on the top of a 110 meters
high viaduct pier. At the time of this experiment the top of
the pier could move freely. I've collected 20 Hz GPS
L1+L2 RINEX data both on top of the pier and at a reference
site, 1200 meters away. The processing of the RINEX files was
done mainly using "fix and hold" integer ambiguity resolution
strategy. I´ve got some interesting results:</div>
<div><br>
</div>
<div>a) A East-West 24-hours cycle oscillation was detected; I
suppose that it was due to the effect on the pier of the
apparent diurnal movement of the sun.</div>
<div>b) We were able to extract, from the displacements of the
top pf the pier, the first natural frequency of the pier
(around 0.5 Hz)</div>
<div><br>
</div>
<div>For the last three months I have been conducting
experiments to compare RTKPOST processing of RINEX files with
the RTK output of a very well known top-level professional
software (made by a very well known company). At the same time
I have been testing the use of wireless radio antenas to
conect the sation sites to the reference site.</div>
<div><br>
</div>
<div>Apart from this experiments I'm still strugling with some
theoretical concepts regarding GNSS positioning. It is still
not clear to me the exact meaning of a number of terms that I
find here and there. I suppose that there is still no
uniformity in naming some key concepts of high-precision
(centimeter or sub-centimeter) GNSS positioning. And I still
need to truly learn the fundamentals of high-precision real
time GNSS positioning, namely the distinct ambiguity
processing strategies and the different positioning modes
used.</div>
<div><br>
</div>
<div>Regards</div>
<div><br>
</div>
<div>Antonio</div>
<div><br>
<div class="gmail_quote">2012/6/29 Mauro Ugarte Avilés <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:mauro.ugarte@cefop.udec.cl" target="_blank">mauro.ugarte@cefop.udec.cl</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Dear Antonio,<br>
<br>
It's been a while since we talked about RTKLIB and all
those networking options.....how is it going?<br>
<br>
I would be glad to know something about your overall
results, or some partial results regarding the
monitoring of structures you where conducting.....I'm
planning to learn a little bit of the absolute basics
in the civil engineering fields where precise
positioning could apply, particularly in the area of
land surveying, in order to study possible solutions
to some of it's requirements trough the use of rtklib.<br>
<br>
(Any other list memeber's comments about some
experience in this particular application of precise
positioning (RTK, PPP or even DGPS), are really
welcome.)<br>
<br>
Best regards!<br>
<br>
<pre cols="72">Mauro Ugarte A.
Ingeniero de Desarrollo
División de Instrumentación Óptica y Tecnologías de Teledetección
Centro de Óptica y Fotónica
Universidad de Concepción
F/Fax: 2204740 | <a moz-do-not-send="true" href="mailto:mauro.ugarte@cefop.udec.cl" target="_blank">mauro.ugarte@cefop.udec.cl</a>
</pre>
<div>
<div> On 26/10/11 19:05, António Pestana wrote:<br>
</div>
</div>
</div>
<blockquote type="cite">
<div>
<div><br>
<br>
<div class="gmail_quote">2011/10/26 Mauro Ugarte
Avilés <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:mauro.ugarte@cefop.udec.cl"
target="_blank">mauro.ugarte@cefop.udec.cl</a>></span><br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#ffffff" text="#000000">
<div><br>
</div>
Regarding that chapter, you should use as
your network topology, the example 4 (Wifi)
or 5 (mobile phone network), and replace on
both of those examples the block "RTKNAVI"
by Spider (and maybe move Spider to the
"Base Station" or reference receiver's PC,
and "STRSVR" to the remote receiver's PC) .
If there is going to be line of sight
between both locations, a Wireless Router or
Access Point connected at the Base Station's
PC Ethernet port (or wirelessly), an a USB
wireless adapter with detachable antenna at
the rover's PC (this one, for example: <a
moz-do-not-send="true"
href="http://www.tp-link.com/en/products/details/?model=TL-WN722N"
target="_blank">http://www.tp-link.com/en/products/details/?model=TL-WN722N</a>),
with both antennas (the AP/router and the
USB adapter) replaced by a directional Wifi
antenna like this one: <a
moz-do-not-send="true"
href="http://www.tiendecita.com/antena-wifi-planar-estanca-marca-abaks-p-99.html"
target="_blank">http://www.tiendecita.com/antena-wifi-planar-estanca-marca-abaks-p-99.html</a>,
should do it. (Note that the antenna does
not include the coaxial cable needed to
connect the antenna to the AP/router (that
by the way has to have a detachable antenna
also, in order to replace it), but that
cable can be easily found on computer
stores). The USB wireless adapter used at
the remote receiver's PC should be placed
inside the box behind the antenna, were the
RP-SMA connector is. <br>
</div>
</blockquote>
<div><br>
</div>
<div>Once again very useful tips. Thanks.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#ffffff" text="#000000">
<div> <br>
</div>
My fault, no examples...but at least RTKLIB
has a manual....and there are screen
captures on it!! At the GNSS positioning
techniques FOSS world, those features are
not very usual... ;-). </div>
</blockquote>
<div><br>
</div>
<div>Yes. I must agree with you. The manual is
very good.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#ffffff" text="#000000">Based on
that brief descriptions, you would be able
to find better explanations somewhere else:
papers, doctorate theses, GNSS equipment
manufacturers, etc.<br>
</div>
</blockquote>
<div><br>
</div>
<div>That's what I'm trying to do these days... </div>
<div><br>
</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#ffffff" text="#000000"> You
will be sensing large structures, right? In
that case, I would go with "static" (static
rover, static reference), not "moving-base"
(moving rover, moving reference) nor "fixed"
(constant distance between rover and base).
Maybe you could go with kinematic too, if
the real-time displacements and deflections
of the structures studied can be considered
as "movement".<br>
<br>
</div>
</blockquote>
<div><br>
</div>
<div>My structures move at relatively high
frequencies (say from 0,1 to 5 Hz). Most of
the movements are small (a few centimeters at
most).</div>
<div><br>
</div>
<div>Best regards</div>
<div><br>
</div>
<div>Antonio</div>
</div>
<br>
<br>
<fieldset></fieldset>
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</div>
</div>
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