Ah, i'll have to look into the .cap file format and use it for parsing. Either that or pipe the airodump output to a program that can parse it and track the locations of all users.
By the way, do you have a copy of the images on the first page? The freeantenas.com site seems to be down and it would be nice to have those for future reference.
I'm currently toying with a 3 antenna type monitoring system, where two use monopole antennas for a power reading to determine proximity and a nice set of square root functions to figure out where the signal is originating from in reference to the antennas and a middle antenna to determine directionality.
What i have in mind for the directionality one is a monopole antenna with a big metal sheet/half-box blocking signals from one direction. The purpose of the blocking is that if the signal is strong(er) in relation to the average of the two detectors, then its on the side that isn't blocked off. If its weaker, than its on the other side.
However, the problems with such a system are far too many to make in a practical sense.
Issues faced by such a system:
Varying power outputs from cards, i.e. an atheros may not output the same power level as a d-link or a wireless chipset may not broadcast as much power on battery mode as during plugged in mode.
a +5db gain antenna attachment will skew the location coordinates for something that detects based on power levels alone.
A cantenna may be able to bypass this completely and appear to be sitting right next to the AP.
The other idea i'm toying is more complex as it may involve a sweeping parabolic or a set of them and use the angle of peak power level to determine the point (two intersecting lines = person).
But this runs into problems of servos or stepper motors with interference and timing, the time based (angle ~ amount of time into sweep/period) angle detection is a problem as packets aren't sent at a uniform rate.
Who knows, if i ever went for a masters, this could probably serve as a thesis in electrical engineering - communications.