<div dir="ltr"><div>before anything else, check what accuracy you get </div><div>with the rover parked for a couple of hours. </div><div><br></div><div>to isolate which one between rover and base </div><div>is noisier, download data from the nearby CORS, </div><div>then process your base versus CORS and your rover</div><div>versus CORS separately.</div><div><br></div><div>keep your base as close as possible to the rover.</div><div>that's the best way to mitigate iono delay </div><div>without dual-frequency tracking data.</div><div><br></div><div>turn on the GPS on the rover for some time </div><div>before it departs, as it should help with </div><div>ambiguity resolution.</div><div><br></div><div>try to elevate the antenna above the body</div><div>of the robot, so as to minimize multipath </div><div>and EM interference.</div><div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Sep 17, 2014 at 6:06 PM, <span dir="ltr"><<a href="mailto:foss-gps-request@lists.osgeo.org" target="_blank">foss-gps-request@lists.osgeo.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Send FOSS-GPS mailing list submissions to<br>
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Today's Topics:<br>
<br>
1. Mobile Robot Experimentation (Sean Hyde)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Wed, 17 Sep 2014 17:05:35 -0400<br>
From: "Sean Hyde" <<a href="mailto:sean.a.hyde@gmail.com">sean.a.hyde@gmail.com</a>><br>
To: <<a href="mailto:foss-gps@lists.osgeo.org">foss-gps@lists.osgeo.org</a>><br>
Subject: [FOSS-GPS] Mobile Robot Experimentation<br>
Message-ID: <0ddc01cfd2bb$20551d40$60ff57c0$@<a href="http://gmail.com" target="_blank">gmail.com</a>><br>
Content-Type: text/plain; charset="us-ascii"<br>
<br>
Hey Guys,<br>
<br>
<br>
<br>
I've been playing around with RTKLib for a couple months now and have run<br>
into some issues and I was wondering if anyone had any idea on how to<br>
improve performance.<br>
<br>
<br>
<br>
---Setup---<br>
<br>
Base Station:<br>
<br>
NVS08C on custom PCB using the receiver to power the antenna<br>
<br>
Antenna is Taoglas Limited AA.161.301111<br>
(<a href="http://www.taoglas.com/images/product_images/original_images/AA.161.301111.
pdf" target="_blank">http://www.taoglas.com/images/product_images/original_images/AA.161.301111.<br>
pdf</a>)<br>
<br>
Antenna is on a 12" x 24" steel plate<br>
<br>
Connected via FTDI->USB to Rasperry Pi<br>
<br>
Raspberry Pi runs str2str to send the data to Windows laptop running rtknavi<br>
using wifi backhaul<br>
<br>
<br>
<br>
Rover:<br>
<br>
NVS08C on custom PCB using the receiver to power the antenna<br>
<br>
Antenna is Taoglas Limited AA.161.301111<br>
(<a href="http://www.taoglas.com/images/product_images/original_images/AA.161.301111.
pdf" target="_blank">http://www.taoglas.com/images/product_images/original_images/AA.161.301111.<br>
pdf</a>)<br>
<br>
Antenna is on a 18" x 18" steel plate<br>
<br>
Connected via FTDI->USB to Rasperry Pi<br>
<br>
Raspberry Pi runs str2str to send the data to Windows laptop running rtknavi<br>
using wifi backhaul<br>
<br>
<br>
<br>
The Rover setup is on a small mobile robot with a top speed of about 3mph.<br>
It is in a city (Pittsburgh), but the sky is relatively unobstructed.<br>
<br>
<br>
<br>
I'm running rtknavi in Kinematic mode using only GPS, L1+L2, 15deg elevation<br>
mask. The position that I input for the base station is a 5 hour average<br>
(though it seems to have lost some precision when I pasted it?). I have<br>
tried both Continuous and Fix and Hold Integer Ambiguity Res. I'll try to<br>
attach screen shots of rtknavi.<br>
<br>
<br>
<br>
Right now, it kind of works. I can get relatively jitter-free floats and<br>
occasionally fixes, but these fixes don't last long and I'm not sure they<br>
are actually globally accurate (ie: if you restart the software, you may get<br>
a fix, but it may be several meters from your last fix). Sometimes a fix<br>
goes away and never seems to come back.<br>
<br>
<br>
<br>
I'm wondering if you guys have any suggestions to improve these results.<br>
<br>
Better antennas? (Which ones?)<br>
<br>
Trying to get better placement of the base station?<br>
<br>
Different settings in rtknavi?<br>
<br>
Continuous vs Fix and Hold?<br>
<br>
<br>
<br>
Thanks!<br>
<br>
-Sean<br>
<br>
<br>
<br>
<br>
<br>
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</blockquote></div><br></div></div>