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

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Thu Mar 31 18:23:09 UTC 2011

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:


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:


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:


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.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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