<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hey Guys,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’ve been playing around with RTKLib for a couple months now and have run into some issues and I was wondering if anyone had any idea on how to improve performance.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>---Setup---<o:p></o:p></p><p class=MsoNormal>Base Station:<o:p></o:p></p><p class=MsoNormal>NVS08C on custom PCB using the receiver to power the antenna<o:p></o:p></p><p class=MsoNormal>Antenna is Taoglas Limited AA.161.301111 (<a href="http://www.taoglas.com/images/product_images/original_images/AA.161.301111.pdf">http://www.taoglas.com/images/product_images/original_images/AA.161.301111.pdf</a>)<o:p></o:p></p><p class=MsoNormal>Antenna is on a 12” x 24” steel plate<o:p></o:p></p><p class=MsoNormal>Connected via FTDI->USB to Rasperry Pi<o:p></o:p></p><p class=MsoNormal>Raspberry Pi runs str2str to send the data to Windows laptop running rtknavi using wifi backhaul<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Rover:<o:p></o:p></p><p class=MsoNormal>NVS08C on custom PCB using the receiver to power the antenna<o:p></o:p></p><p class=MsoNormal>Antenna is Taoglas Limited AA.161.301111 (<a href="http://www.taoglas.com/images/product_images/original_images/AA.161.301111.pdf">http://www.taoglas.com/images/product_images/original_images/AA.161.301111.pdf</a>)<o:p></o:p></p><p class=MsoNormal>Antenna is on a 18” x 18” steel plate<o:p></o:p></p><p class=MsoNormal>Connected via FTDI->USB to Rasperry Pi<o:p></o:p></p><p class=MsoNormal>Raspberry Pi runs str2str to send the data to Windows laptop running rtknavi using wifi backhaul<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The Rover setup is on a small mobile robot with a top speed of about 3mph. It is in a city (Pittsburgh), but the sky is relatively unobstructed.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m running rtknavi in Kinematic mode using only GPS, L1+L2, 15deg elevation mask. The position that I input for the base station is a 5 hour average (though it seems to have lost some precision when I pasted it?). I have tried both Continuous and Fix and Hold Integer Ambiguity Res. I’ll try to attach screen shots of rtknavi.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Right now, it kind of works. I can get relatively jitter-free floats and occasionally fixes, but these fixes don’t last long and I’m not sure they are actually globally accurate (ie: if you restart the software, you may get a fix, but it may be several meters from your last fix). Sometimes a fix goes away and never seems to come back.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m wondering if you guys have any suggestions to improve these results.<o:p></o:p></p><p class=MsoNormal>Better antennas? (Which ones?)<o:p></o:p></p><p class=MsoNormal>Trying to get better placement of the base station?<o:p></o:p></p><p class=MsoNormal>Different settings in rtknavi?<o:p></o:p></p><p class=MsoNormal>Continuous vs Fix and Hold?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks!<o:p></o:p></p><p class=MsoNormal>-Sean<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><img border=0 width=397 height=319 id="Picture_x0020_1" src="cid:image001.png@01CFD299.98E18720"> <img border=0 width=392 height=314 id="Picture_x0020_2" src="cid:image002.png@01CFD299.98E18720"> <img border=0 width=386 height=308 id="Picture_x0020_4" src="cid:image003.png@01CFD299.98E18720"> <img border=0 width=409 height=266 id="Picture_x0020_5" src="cid:image004.png@01CFD299.98E18720"><o:p></o:p></p></div></body></html>