> The first input you need is the exact longitude/latitude of the > lightning bolt. > > The easiest way to do that is with a set of GPS synchronized receivers, > aaaand we're back to sqare one!
That's true for ultimate accuracy. But notice how each strike is seen by dozens of observers and each observer knows their (fixed) position and has their own local (approximate) clock. So it seems to me it's not unlike how GPS works: with enough samples, it should be possible to solve for latitude, longitude, and time of each strike. Like running GPS in 3D mode rather than position hold (zero D) mode. Now the accuracy is clearly not going to be at the nanosecond level. Maybe not even microsecond level, since as you mentioned, there are biases and jitter and who know what propagation variations. But over time, you should be able to converge on differential local clock measurements. What I'd like to see is the TDEV of this as a common view time transfer method. A couple of hops and we could compare UTC(PHK) with UTC(TVB), for example. Perhaps another side effect of their lightning project is that it could create dynamic propagation maps using the residuals in their massive database. When I first owned WWVB gear I thought I had accurate time. After I got GPS, I realized that my WWVB receivers now became accurate Colorado-to-Seattle weather stations. As they say, one man's error is another man's signal. /tvb _______________________________________________ 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.
