I would be interested in trying the hostapdsql diff Sam Fourman Jr.
On 12/18/06, Reyk Floeter <[EMAIL PROTECTED]> wrote:
On Sun, Dec 17, 2006 at 12:09:12PM -0600, Jacob Yocom-Piatt wrote: > only today have i tried out hostapd, it is quite neat. while adding a 2nd AP to > my network a thought occurred to me: if you had >3 APs that were sufficiently > spread out and had tightly synced clocks you could likely triangulate the source > of a wifi signal with a fair deal of accuracy. > > is this doable? > yes but it needs some heavy math ;). you can get some results by using the signal strength, but it is probably better if you also use the round trip time and some low level information. once we implemented it with hostapd, a sql patch (to allow the central hostapd sensor to log into a postgresql database), some gps coordinates, and a hacked psql script to directly query the triangulated results from the database. a guy from the ccc implemented a php frontend to draw the station coodinates on an area map, but i would prefer an implementation using svg and firefox without the need of a server-side scripting language now ;). unfortunately, our code got lost after the experiment, but i may still find the hostapdsql diff. reyk
