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