Mark, What type of real-time surveying software are you using? I'm looking for surveying/plotting software for Linux to keep a close on the timing stability of my Adafruit.
Bob - AE6RV >________________________________ > From: Mark Sims <hol...@hotmail.com> >To: "time-nuts@febo.com" <time-nuts@febo.com> >Sent: Monday, November 4, 2013 7:13 PM >Subject: [time-nuts] Computing GPS Distance Error in Time > > >I was using the Adafruit GPS receivers to calculate the bearing and distance >between two boxes that had radio tranceivers in them. The control box polls >the remote box position and does simple trig on the difference between the GPS >coordinates. I noticed that the Adafruit GPS seems to go into some kind of >funky "position hold" mode if thinks that it is not moving (or is actually >moving very slowly)... the GPS coordinates stop updating until the box moves >some distance. >I got much better results using a CN06 GPS module that is based upon the Ublox >Neo-6M. You need to solder a wire to the Neo module to access its PPS output. > HobbyKing sells them for cheap... also lots of sellers on Ebay. I could >put one box on the ground, and move the other one around it only a couple of >feet away. It gave remarkably good results considering the boxes were much >closer than the average GPS error... it is basically a differential GPS >application. Also, the processor is an AVR running single precision floats. >I laid out a breakout board that can take the Adafruit, CN06, or Trimble >Resolution T GPS boards and convert the TTL/CMOS levels to true RS-232 levels >via a MAX3232 chip to a DE-9 connector. PPS polarity is jumperable. > >_______________________________________________ >time-nuts mailing list -- time-nuts@febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
