Hi, I thought I would pass this along to demonstrate that all uses of crypto are not 'real world'... Hope you enjoy. Jim Choate CyberTects ravage@ssz.com Forwarded message:
To: traveller@MPGN.COM Subject: Re: Aperture Synthesis, Aegis Date: Sun, 26 Jan 1997 21:40:18 +0000
At 08:15 AM 1/26/97 +0000, you wrote: <snip>
For example, at 5 ls, you have ship A sending data to ship B, which has to know "exactly" how long it took for the data to cross the gap, as that's one of the parameters in the calculations.
If it's "exactly" 5 seconds, then each ship "combines" the data it receives directly with the data received 5 seconds later from the other ship. The combining involves various things like trig and other messy stuff. But it all boils down to "A saw X1 from direction Y1 at time Z1, B saw X2 from Y2 at Z2". You combine the info and triangulate.
So at 5 ls, you have a "data lag" of the 5 seconds it takes the signal to cross the distance *plus* the processing time.
And since the distance *will* vary, even if only by a little bit, that changes the point in the your datastream that you are comparing with the datastream from the other ship.
Could we presume that vessels operating together would have some type of synchronized timekeeping, such as an atomic clock, in each ship, with each message between ships being time & velocity stamped so that each receiver could adjust the data for integration to local data?
We should also assume a really good (and closely gaurded) encryption on the interchanges, or enemy intercepts would be right dangerous.
Adventure possiblity: trying to obtain a given unit's encryption code or seeking to recover said code.