| And wearing a tin foil hat just makes you a better reflector! Anyway, if you look up through-wall radar detection, most of the implementations use S-band radar, and it is probably safe to assume that it's already been figured out how to use wifi stations and devices already in place emitting signals to each other, rather than always needing to bring additional equipment. With regard to privacy though, it seems like it would be data and computationally intensive to track the movements of people in a large number of houses. Let's say that a hypothetical application could only detect velocities away from or toward the base station, but no directional information. With each movement you make it would build a set of hypotheses about your location. Then when you make another movement, it would need to branch out, and create an entire set of hypotheses for each hypothesis in the previous set, and so on with each movement. While the program could abandon entire branches when they showed you walking through a wall, it would still grow very quickly. Though it is possible to mine data of cell phone locations and CC television cameras after the fact, it seems like (if my understanding of how the technology would work is anything near reality) it is simply too difficult to collect a lot of information about people's movements in their homes without a specific prior reason to justify the expense. Anyway, perhaps rather than tinfoil hats, people worried about surveillance should hang lots of mobile sculptures in their houses to create confounding noise instead. |