Hi John, I suspect that you are correct re the syncronisation issue. Hardware can be a bit of a problem since I am usually writting the code for different PDA's to use as data logger - Dell Axim51, ASUS various, iPAQs various - and generrally rely on 1 commplete set of messages per second at 9600 baud, every 2 seconds at 4800. Have been provided a couple of suggestions to tighten up the comms code which I am looking at. Thanks Keith
--- In [EMAIL PROTECTED], "John Carter" <[EMAIL PROTECTED]> wrote: > > --- In [EMAIL PROTECTED], William Keith Saalfeld > <ksaalfeld@> wrote: > > > >I just cannot help feeling that there has to be a tighter set of > code to do this job. At 9600 baud I should be getting up to 2 $GPGGA > sentences per second. > > > > Normal NEMA output is once per second. Depending on the specific GPS > unit, it may allow you to specify that it only send a single NEMA > sentence (RMC, GGA, etc). A GPS' default output may very well be > sending RMC every second and GGA every other second (or some such > pattern). Unless the GPS itself can compute and send faster than > once per second, your best capture may be 2 to 3 seconds, because > data collection is NOT synchronized with the GPS output. There's a > message every second *timed by the GPS clock*; sometimes your code > will read the GPS at the beginning of a cycle, other times you are at > the end of a cycle. > > Unless there's some way to provide on-demand output from the GPS, > it's likely that synchronization is not possible and you may already > have the best timing available. > > I don't remember the specific hardware being mentioned (on the other > hand, I'm on prescription painkiller today) and I haven't read all of > your code (I wouldn't process that very well now ;-) > > The hardware will be the key as to whether faster GPS data collection > is possible. > > John > > > I am keen to tighten this code up but need direction to some good > serial comms references that aren't to technical (written for > graduate programmers). > > > > Ta > > Keith > > > > W Keith Saalfeld > > WKS Wildlife Management Consulting > > PO Box 8261 > > Alice Springs NT 08701Australia Mob: 0428 848 912Email1: > ksaalfeld@ > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nsb-ce" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/nsb-ce?hl=en -~----------~----~----~----~------~----~------~--~---
