From: Dr Bruce Griffiths <[EMAIL PROTECTED]> Subject: Re: [time-nuts] 5370B on eBay, carrier phase tracking GPS receiver Date: Mon, 19 Feb 2007 16:53:55 +1300 Message-ID: <[EMAIL PROTECTED]>
> Brooke Clarke wrote: > > Hi Bruce: > > > > Is there a paper describing the method? > > > > Have Fun, > > > > Brooke Clarke > > > > Have Fun, > > > > Brooke > > > > w/Java http://www.PRC68.com > > w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml > > http://www.precisionclock.com > > > > > > > > Dr Bruce Griffiths wrote: > > > > > Brooke > > Yes I think that Magnus posted it some time ago: > > http://tycho.usno.navy.mil/ptti/ptti99/PTTI_1999_405.PDF There is another paper just before it. There is also a patent for a specific form of implementation. > Note they used an Oncore VP, the Superstar has a better carrier phase > tracking.performance. What they did was that they hooked their Oncore VPs up to cesium beams for test purposes. Locking that clock with a not-so-perfect but sufficient for the task ratio. You can do about the same without too much difficulty, but the Allstar, Superstar and Superstar II receivers belong to those that is built out of the Zarlink chipsets which all feature an interesting issue, the use of a 10 MHz TCXO. Now, this frequency should be fairly know to us time-nuts, no? ;) Wiring in an externally supplied 10 MHz should not be all that difficult. The receiver is now effectively a high resolution phase comparator between the selected sats and the timing source used for reference. The PPS output of the receiver is not used for reference, but rather the carrier phase pseudo-ranges. Either you tap the pseudo-range data out and do the dirty stuff outside, or you have the receiver do all the calculations. Having a reciever do some interesting corrections on pseudoranges may be a bit harder thought. Anyway, if you do things properly, it will be a much better solution than looking at that PPS. Cheers, Magnus _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts