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

Uwe Klein uwe_klein_habertwedt at t-online.de
Thu Mar 31 18:35:00 UTC 2011


Terje Mathisen 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 
>>
look into source from b747.sourceforge.net

>>
> 
> 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:
> 
> $PMTK513,1*28<CR><LF>
did you compute the proper chksum?
> 
> 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.
> 
> (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.
> 
Have you got a working tcl installation?
( I have rather complete software written to read and write NMEA sentences.
    targeted initially at a ships set of NMEA stuff, highlight is on AIS traffic.)
> Terje
> 

G!
uwe




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