Tom, On 09/04/2013 11:05 PM, Tom Van Baak wrote: > Hi John, > > It's not off-topic at all. Thanks for posting. Someday it would be cool if an > amateur precise time project emerged from this effort. > > What is not clear from your link is the accuracy or stability of the LO that > was used. It seems to me, for timing purposes, that one would want to have a > very precise timebase for the binary samples that are collected. > > I suppose it depends if someone just wants to make a homebrew (50 baud) GPS > subcode decoder and navigation receiver, or if someone is interested in > extracting as much precise time from the code and carrier phase as possible. > For our timing niche, SDGPS (Software-Defined GPS) doesn't even need to be > real-time. It's the after-the-fact corrections to the LO that are of interest. Naturally the LO and filtering is important. There is a bit more than the 50 baud data you need to grab, but once you have your observables, just putting them onto a file works. However, doing fair amount of processing on that stream of data isn't very daunting. Getting down to 1 kHz is a bit cycle-consuming, so a good front-end processing for that is a good idea.
I've naturally toyed with grabbing a gig or so of samples from the air and put them on file, and then post-processing them, locking up to birds and extracting data. Cheers, Magnus _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
