17 Dec
2003
17 Dec
'03
11:17 p.m.
Which suggests a "stealth" phone that randomly dithers its round trip delay a la GPS selective availability... Well, I'm not sure how well that would work... The "dither" on the RTT can't go negative (for obvious reasons :-) ). Presumably the dither turns a "He's somewhere on this circle" into a "He's somewhere inside this circle". If you vary the dither over time, someone trying to track you would wait for the RTT to hit a local minimum to get the most precise fix. If the dither introduced by the phone has to be the same for all cell sites, it gets even easier. - Bill