> Yes I agree a newer thunderbolt would surely suffice for me and probably > also the ocxo in my 8662A synth > > But I am still academically curious about the impact of more channels of > satellites? What is the value of these extra sats? > Thanks!
In a mobile scenario, you need measurements to four or more satellites to solve for x,y,z and time. A ground vehicle travelling in areas with lot of antenna masking - high buildings close to the road or trees - blocking line of sight from antenna to the satellites, will want to track all satellites in view. And since especially low elevation satellites will come and go, you want to pick these up really quick once visable. Thus you want as many channels (correlators) as possible. For a stationary timing scenario, (x,y,z) might be known - or averaged over many measurements (site survey). This gives that in a timing mode the receiver only needs to track one satellite. The GPS receiver evolution moved from 1-channel multiplexing, to 6 channels, and 8, 12 and even more. While there might be timing variants of generic navigation receiver, the core correlator chipsets are shared. So even if the timing receiver does not benefit that much from 8+ channels, once the navigation receivers got more channels, the timing versions had to follow. Modern timing receiver have better hardware to put the 1PPS signal where intended. Se http://www.leapsecond.com/pages/vp/sawtooth.htm for a comparison of semi modern receiver and an old one. This might have a bigger impact than the number of channels. -- Björn _______________________________________________ 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.
