Thanks for the suggestion. Does the DSSS make it easier to correlate between ground stations? I'm not sure how to handle the phase offset on the 10 MHz ref clocks. -Bob
> On Mar 26, 2015, at 07:25, Attila Kinali <att...@kinali.ch> wrote: > > On Wed, 25 Mar 2015 21:27:35 -0500 > Robert Watzlavick <roc...@watzlavick.com> wrote: > >> I'm working on a project that I could use some advice on and also might >> be of interest to the list. If it's not appropriate for the list, my >> apologies. > > The gods have apporved of your request. You may speak now. > ;-) > >> I want to develop a tracking system for an amateur rocket that can allow >> me to track the rocket even if onboard GPS is lost (as is typical during >> ascent and sometimes during descent) or if telemetry is lost. > > Given you can synchronize the clocks of the ground stations well > enough, then the rest is "easy". Then you can get away with having > a simple signal generator that only needs an XO. Or you can go > for a TCXO to make your signal processing life easier. > > What you need to do, is actually the same as GPS does: Create a > direct spread spectrum signal and track it on all ground stations. > The DSSS has the advantage over the single pulse, that it's more > resilient against noise and interference. The disadvantage is, that > you have to have more complicated hardware. One viable way would be, > that you have precisly synchronized sampling systems (e.g. SDR's like > the bladeRF which can take an external clock) and then feed the data > to a PC where you do the heavy lifting. Then you don't need to build > custom hardware at least. > > Also, if the precision by the DSSS signal is not good enough, you can > apply various tricks from the GPS world, like carrier phase tracking, etc. > > HTH > > Attila Kinali > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neil Stephenson > _______________________________________________ > 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.
