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[DPRG] GPS and ground planes
Subject: [DPRG] GPS and ground planes
From: Jeff Sampson
jsampson at pobox.com
Date: Sun May 4 03:30:35 CDT 2008
Kenneth Maxon wrote:
>
> Question: On the SMIRF(II) chipset that you have been using, have you ever
> been able to get a lock on the WAAS signal? On the SMIRF (III) I have not
> been able to receive it and do not know if it is my location or the way I am
> interfacing to the chipset.
>
> -Kenneth
The Sparkfun EM-408 requires a command to turn on WAAS. According to
article 1 here:
http://www.kronosrobotics.com/Projects/GPS.shtml
I downloaded this porgram:
http://homepage2.nifty.com/k8/gps/#001
For the EM-406 Sirf III it says DGPS Fix. Looking at the NMEA data sheet
from Sparkfun I found the GGA sentence. For Fix Position Indicator field
it says:
0 Fix not available or invalid
1 GPS SPS Mode, fix valid
2 Differential GPS, SPS Mode, fix valid
3-5 Not supported
6 Dead Reckoning Mode, fix valid
The actual sentence is:
$GPGGA,080419.000,4500.7494,N,09314.6463,W,2,05,1.3,272.7,M,-31.9,M,0.8,0000*49
It does have a 2 in field 7. So I assume that is the WAAS.
The Sirf II won't lock on in my living room at the moment. Here is old
data and it has a 1 in the field. So I assume my Sirf II does not have
WAAS or it needs a command to turn it on.
$GPGGA,200456.799,4500.7594,N,09314.6350,W,1,07,1.1,233.7,M,-31.9,M,9.4,0000*4A
--
Jeff Sampson
http://tcrobots.org/members/jsamp.htm
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