On Mon, Sep 05, 2011 at 04:47:20PM +0000, unruh wrote: > On 2011-09-05, Miroslav Lichvar <mlich...@redhat.com> wrote: > > It's from gpsd which seems to make the NMEA receive timestamp after > > the message is processed. > > > Never did understand that. Timestamping the beginning of the sentences > is cheap enough and easy enough. > Mind you, your fluctuations are far more than I would expect simply from > variations in the length of the sentences. > Are there more sentences delivered than just the one gpsd uses?
There are other messages enabled (I like to monitor the visibility of satellites in cgps), but RMC and GGA are transmitted first. The baud rate is set to 115200. The measured time it takes to transmit one batch is about 85 +/- 10 ms. Here is another capture, this time only over couple hours, but it's the offset to the beginning of the transfer (i.e. start of RMC). http://mlichvar.fedorapeople.org/tmp/18x_nmea2.png The offset still moves in a 300ms range. -- Miroslav Lichvar _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
