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 href="mailto:mauro.ugarte@cefop.udec.cl" target="_blank">mauro.ugarte@cefop.udec.cl</a>></span><br>
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<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 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 href="mailto:mauro.ugarte@cefop.udec.cl" target="_blank">mauro.ugarte@cefop.udec.cl</a>></span><br>
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<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 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 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>
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<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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