Hmmm...Inject a different signal into every grid in every country on every planet. That would only localise the location to a grid, getting a location of a house, or even a suburb, would require a mind boggling stretch of the imagination. As has been said, battery operated camera, data compression and frequency limited microphones are just a few of the problems. It doesn't matter what ENF/FFT analysis is employed, you can't extract information from nothing. Once a signal is too far down in the noise level it cannot be reconstructed with any degree of fidelity. However, on positive note, I do see a Hollywood movie coming out of this.