Re: opensource_gps Digest, Vol 65, Issue 1
Siddharth Paliwal <[email protected]> Mon, 7 Feb 2011 01:14:05 +0530
| Newsgroups | gmane.comp.hardware.gps.opensource |
|---|---|
| Message-ID | <[email protected]> |
--===============4271760048379863172== Content-Type: multipart/alternative; boundary=0022152d6039b5d458049ba25761 --0022152d6039b5d458049ba25761 Content-Type: text/plain; charset=ISO-8859-1 Thanks for the reply, Doug and Mark. For my application I require a short length cable only (about 35 cm or so), and I wasn't able to find any resource to get only 2-3 pieces manufactured so I got it modified by some person who had done it before a few times. I was suggested to use a Network Analyzer to measure the return loss and check for impedance discontinuities in the cable. I am seeing to it and will get back with results. And about the gain values, isn't it possible to reduce False alarms by reducing the Threshold value, for which the state transits from Acquire/Confirm to Pull-in ? On Sun, Feb 6, 2011 at 1:55 AM, Doug Baker <[email protected]> wrote: > Hello Siddharth, > > Most likely the shortened coax cable is causing the front-end of the > receiver to be overloaded with too much gain. The cable length that comes > with that Trimble antenna is such that it provides enough attenuation to > work properly with that receiver. > > You may want to try adding some coax back to that antenna to introduce loss > in order to get the correct amount of gain. > > Regards, > > Doug Baker > GPS Creations, Inc. > PO Box 381272 > Germantown, TN 38183-1272 > USA > Cell Phone: 949-547-0608 > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > [email protected] > Sent: Saturday, February 05, 2011 2:00 PM > To: [email protected] > Subject: opensource_gps Digest, Vol 65, Issue 1 > > Send opensource_gps mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of opensource_gps digest..." > > > Today's Topics: > > 1. Antenna modification - False Acquisitions problem > (Siddharth Paliwal) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 5 Feb 2011 12:35:05 +0530 > From: Siddharth Paliwal <[email protected]> > Subject: [OpenSource_GPS] Antenna modification - False Acquisitions > problem > To: [email protected] > Message-ID: > <[email protected]> > Content-Type: text/plain; charset="iso-8859-1" > > Hello, > > I am running the GPL-GPS code on the GPS600 receiver that I purchased from > GPS Creations. I had to modify my Antenna(Trimble) cable length for some > reasons, so I got the cable shortened and got another connector re-crimped > to it. But this modified Antenna seems to have some problems. Now I am > unable to get lock on satellites, but there seem to be a large no. of False > Acquisitions, in the sense that most of the channels (out of 12 available) > now transition upto the Pull-in state and then fall back to Acquisition > state. And the code seems to be running perfectly fine with an unmodified > Trimble Antenna (tracking up to 6-7 satellites !!). > Is there any way to check if there are any problems with my modified > Antenna > (probably Impedance matching problems?) besides running it on the GPS > receiver and checking If I'm able to lock satellites or not. And also what > are the possible places at which I might have gone wrong? > Any help would be highly appreciated. > > Thanks. > > -- > Siddharth Paliwal > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > < > http://lists.psas.pdx.edu/pipermail/opensource_gps/attachments/20110205/bdb > 3e3ed/attachment.html> > > ------------------------------ > > _______________________________________________ > opensource_gps mailing list > [email protected] > http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps > > > End of opensource_gps Digest, Vol 65, Issue 1 > ********************************************* > > > > _______________________________________________ > opensource_gps mailing list > [email protected] > http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps > -- Siddharth Paliwal Pre-final year Undergraduate Dept. of Chemical Engineering Indian Institute of Technology, Kanpur --0022152d6039b5d458049ba25761 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Thanks for the reply, Doug and Mark.<div>For my application I require a sho= rt length cable only (about 35 cm or so), and I wasn't able to find any= resource to get only 2-3 pieces</div><div>manufactured so I got it modifie= d by some person who had done it before a few times. I was suggested to use= a Network Analyzer</div> <div>to measure the return loss and check for impedance discontinuities in = the cable. I am seeing to it and will get back with results.</div><div><br>= </div><div>And about the gain values, isn't it possible to reduce False= alarms by reducing the Threshold value, for which the state transits</div> <div>from Acquire/Confirm to Pull-in ?</div><br><div class=3D"gmail_quote">= On Sun, Feb 6, 2011 at 1:55 AM, Doug Baker <span dir=3D"ltr"><<a href=3D= "mailto:[email protected]">[email protected]</a>></span> wro= te:<br> <blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p= x #ccc solid;padding-left:1ex;">Hello Siddharth,<br> <br> Most likely the shortened coax cable is causing the front-end of the<br> receiver to be overloaded with too much gain. =A0The cable length that come= s<br> with that Trimble antenna is such that it provides enough attenuation to<br= > work properly with that receiver.<br> <br> You may want to try adding some coax back to that antenna to introduce loss= <br> in order to get the correct amount of gain.<br> <br> Regards,<br> <br> Doug Baker<br> GPS Creations, Inc.<br> PO Box 381272<br> Germantown, TN 38183-1272<br> USA<br> Cell Phone: 949-547-0608<br> <br> -----Original Message-----<br> From: <a href=3D"mailto:[email protected]">opensour= [email protected]</a><br> [mailto:<a href=3D"mailto:[email protected]">openso= [email protected]</a>] On Behalf Of<br> <a href=3D"mailto:[email protected]">opensource_gps= [email protected]</a><br> Sent: Saturday, February 05, 2011 2:00 PM<br> To: <a href=3D"mailto:[email protected]">opensource_gps@lis= ts.psas.pdx.edu</a><br> Subject: opensource_gps Digest, Vol 65, Issue 1<br> <br> Send opensource_gps mailing list submissions to<br> =A0 =A0 =A0 =A0<a href=3D"mailto:[email protected]">openso= [email protected]</a><br> <br> To subscribe or unsubscribe via the World Wide Web, visit<br> =A0 =A0 =A0 =A0<a href=3D"http://lists.psas.pdx.edu/cgi-bin/mailman/listin= fo/opensource_gps" target=3D"_blank">http://lists.psas.pdx.edu/cgi-bin/mail= man/listinfo/opensource_gps</a><br> or, via email, send a message with subject or body 'help' to<br> =A0 =A0 =A0 =A0<a href=3D"mailto:[email protected]= ">[email protected]</a><br> <br> You can reach the person managing the list at<br> =A0 =A0 =A0 =A0<a href=3D"mailto:[email protected]">= [email protected]</a><br> <br> When replying, please edit your Subject line so it is more specific<br> than "Re: Contents of opensource_gps digest..."<br> <br> <br> Today's Topics:<br> <br> =A0 1. Antenna modification - False Acquisitions problem<br> =A0 =A0 =A0(Siddharth Paliwal)<br> <br> <br> ----------------------------------------------------------------------<br> <br> Message: 1<br> Date: Sat, 5 Feb 2011 12:35:05 +0530<br> From: Siddharth Paliwal <<a href=3D"mailto:[email protected]">= [email protected]</a>><br> Subject: [OpenSource_GPS] Antenna modification - False Acquisitions<br> =A0 =A0 =A0 =A0problem<br> To: <a href=3D"mailto:[email protected]">opensource_gps@lis= ts.psas.pdx.edu</a><br> Message-ID:<br> =A0 =A0 =A0 =A0<<a href=3D"mailto:AANLkTiksePU08GT97nHSkXHbVNZ8dTX%2BB0= [email protected]">AANLkTiksePU08GT97nHSkXHbVNZ8dTX+B0fKu9zf8v6A@ma= il.gmail.com</a>><br> Content-Type: text/plain; charset=3D"iso-8859-1"<br> <br> Hello,<br> <br> I am running the GPL-GPS code on the GPS600 receiver that I purchased from<= br> GPS Creations. I had to modify my Antenna(Trimble) cable length for some<br= > reasons, so I got the cable shortened and got another connector re-crimped<= br> to it. But this modified Antenna seems to have some problems. Now I am<br> unable to get lock on satellites, but there seem to be a large no. of False= <br> Acquisitions, in the sense that most of the channels (out of 12 available)<= br> now transition upto the Pull-in state and then fall back to Acquisition<br> state. And the code seems to be running perfectly fine with an unmodified<b= r> Trimble Antenna (tracking up to 6-7 satellites !!).<br> Is there any way to check if there are any problems with my modified Antenn= a<br> (probably Impedance matching problems?) besides running it on the GPS<br> receiver and checking If I'm able to lock satellites or not. And also w= hat<br> are the possible places at which I might have gone wrong?<br> Any help would be highly appreciated.<br> <br> Thanks.<br> <br> --<br> Siddharth Paliwal<br> -------------- next part --------------<br> An HTML attachment was scrubbed...<br> URL:<br> <<a href=3D"http://lists.psas.pdx.edu/pipermail/opensource_gps/attachmen= ts/20110205/bdb 3e3ed/attachment.html" target=3D"_blank">http://lists.psas.pdx.edu/pipermai= l/opensource_gps/attachments/20110205/bdb<br> 3e3ed/attachment.html</a>><br> <br> ------------------------------<br> <br> _______________________________________________<br> opensource_gps mailing list<br> <a href=3D"mailto:[email protected]">[email protected]= sas.pdx.edu</a><br> <a href=3D"http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gp= s" target=3D"_blank">http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/ope= nsource_gps</a><br> <br> <br> End of opensource_gps Digest, Vol 65, Issue 1<br> *********************************************<br> <br> <br> <br> _______________________________________________<br> opensource_gps mailing list<br> <a href=3D"mailto:[email protected]">[email protected]= sas.pdx.edu</a><br> <a href=3D"http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gp= s" target=3D"_blank">http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/ope= nsource_gps</a><br> </blockquote></div><br><br clear=3D"all"><br>-- <br>Siddharth Paliwal<div>P= re-final year Undergraduate</div><div>Dept. of Chemical Engineering</div><d= iv>Indian Institute of Technology, Kanpur</div><br> --0022152d6039b5d458049ba25761-- --===============4271760048379863172== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ opensource_gps mailing list [email protected] http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps --===============4271760048379863172==--