Spam:[extropy-chat] PRIVACY: GPS darts

Dan Clemmensen dgc at
Thu Apr 22 20:55:23 UTC 2004

Samantha Atkins wrote:

> Hmmm.  Are there any technical reasons such a thing could not be built?
Yes. We've had a long discussion on this.
  1) GPS uses radio wavelengths that require an antenna that is at least 
4cm long.
  2) A transmitter that can send locator signal 100' or more must have 
both a big (4cm or so) antenna and a battery or other energy source will 
sufficient energy.

These constraints are due to the laws of physics and will remain true 
even if the actual electronics are reduced to nano-scale.

Thus, a stealthy injectable system based on GPS location and radio 
transmission is not possible.

It is theoretically possible to build a stealthy tracker, but we need to 
replace both the location system and the transmission system. to avoid 
the antennas. For example, given sophisticated nanotech, we could inject 
a nano-factory that would then manufacture locator dust and leave smart 
trail. The authorities could then follow the trail, or lay a grid of 
more smart dust to intersect the trail. Of course, by the time you have 
such a system, you don't need it, because with that level of nanotech, 
you can just as easily build a universal survailence system. I describe 
it only as an example of a system that does not violate the laws of physics.

Without invoking nanotech, I think a universal surveillance system based 
on cheap cameras with human watchers is quite feasible, given an 
authoritarian government.

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