[ntp:questions] Sure Electronics GPS board: Amazing performance. :-)

unruh unruh at wormhole.physics.ubc.ca
Fri Apr 1 05:52:06 UTC 2011

On 2011-03-31, Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
> Uwe Klein wrote:
>> http://www.google.com/search?client=opera&rls=de&q=MG1613
>> going to have a look into the datasheets.
>> That or ask Sure-Elec or inspect the USB(serial) traffic
>> this could be a start: ( reading currently )
>> http://www.rigacci.org/wiki/lib/exe/fetch.php/doc/appunti/hardware/gps/mtk_packet_user_manual.pdf
> Finally some clues!
> Since I got my board I've been able to procure an RS232 debugger which 
> I've currently got connected between the Sure board and my PC:
> Running the "gps.exe" programwhich can reprogram baud rates, I found a 
> command sequence which isn't covered by that pdf document, but obviously 
> related to them:
> $PMTK251,9600*17<cr><lf>
> is the command to set the baud rate to 9600, so I assume all the other 
> supported rates would be similar, you just have to recalculate the checksum.
> Based on this I tried to use HyperTrm to send the pdf sample command to 
> turn on WAAS capability:

I think WAAS is turned on by default. My sure lists that it is using
DGPS but no DGPS station ID or time since source. It gives about a 1.5m
standard deviation error, which is what you get with WAAS. 

> $PMTK513,1*28<CR><LF>
> but it didn't seem to work. It is possible that the EOL sequence needs 
> to be transmitted without any time gap, so I'll write  tiny program to 
> send custom commands.

Use minicom with the Y command to send a file. On garmin they do not
care that the checksum is sent.

> (I bet I could cut&paste what I need from gpsd...)
> The really crucial command would be nr 314, to enable/disable specific 
> NMEA sentences:
> $PMTK314,1,1,1,1,1,5,1,1,1,1,1,1,0,1,1,1,1*2C<CR><LF>
> The order of the sentences are:
> Supported NMEA Sentences
>      0 NMEA_SEN_GLL,    Geographic Position - Latitude longitude
>      1 NMEA_SEN_RMC,    Recommended Minimum Specific GNSS Sentence
>      2 NMEA_SEN_VTG,    Course Over Ground and Ground Speed
>      3 NMEA_SEN_GGA,    GPS Fix Data
>      4 NMEA_SEN_GSA,    GNSS DOPS and Active Satellites
>      5 NMEA_SEN_GSV,    GNSS Satellites in View
>      6 NMEA_SEN_GRS,    GNSS Range Residuals
>      7 NMEA_SEN_GST,    GNSS Pseudorange Errors Statistics
>     13 NMEA_SEN_MALM,   PMTKALM - GPS almanac information
>     14 NMEA_SEN_MEPH,   PMTKEPH - GPS ephmeris information
>     15 NMEA_SEN_MDGP,   PMTKDGP - GPS diff. corr. information
>     16 NMEA_SEN_MDBG,   PMTKDBG ? MTK debug information
> The example seems to turn on GLL, RMC, GGA, GSA, GSV, GRS (every 5 
> seconds only!), GST, then 5 undocumented sentences (8-12) where the 
> first 4 are on and the last off, followed by the four private sentences.
> Terje

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