Karl Cunningham wrote: > On 3/24/2008 3:28 PM, James G. Sack (jim) wrote: >> Mark Schoonover wrote: >>> On Mon, Mar 24, 2008 at 2:37 PM, James G. Sack (jim) <[EMAIL PROTECTED]> >>> wrote: >>> >>>> Tracy R Reed wrote: >>>>> Neil Schneider wrote: >>>>>> Mark Schoonover wrote: >>>>>> Some dude did a war flight - similar to a wardrive >>>>>>> - in a small plane over San Diego and logged in the thousands. That >>>>>>> was a >>>>>>> few years ago. >>>>>> That would be our own Tracy Reed. >>>>> Indeed it would! >>>>> >>>>> I have been considering reprising this experiment. If anyone has the >>>>> equipment and wants to put together a proper scientific experiment and >>>>> do something unique (triangulate the actual location of the AP, >>>>> acquire >>>>> useful data about the network involved, etc) I would be willing to >>>>> give >>>>> it another go. We could even fly the same path as before and >>>>> compare the >>>>> data. >>>>> >>>> I wonder what kind of antenna you would want/need for this? >>>> >>> I don't know. I've done direction finding work before, but only from >>> a fixed >>> location. DFing from a plane would be very challenging to say the >>> least... >>> Normally you'd use some kind of Adcock array for VHF or UHF, but not >>> sure in >>> the microwave bands. >>> >>> There is some info tho: >>> http://www.scitechpublishing.com/index.asp?PageAction=VIEWPROD&ProdID=158 >>> >>> >> >> Wouldn't a ordinary omni with hopefully not too thick (and not too thin) >> a donut pattern do the job, even? Have to have readings from 2 reception >> points, of course (plus altitude). Assuming a flat earth makes it >> easier, too. ;-) >> >> Seems like a lot of things need to be done at once, though: >> pick a channel >> pick a source >> try to quickly maximize the source signal >> and record direction and altitude >> do fast enough to be able to sample all channels, see strong signals >> >> Are there programs to help with this? Hardware? > > Could have a script that does continuous iwlist scanning. My > recollection is that a scan takes a second or two to complete, but I > don't know if that varies with number of APs found. Record the MAC > address and signal strength for all APs seen during each scan, along > with GPS coordinates (NMEA-183 text from serial port of GPS). Fly a > parallel search pattern. Then (challenge here) post-process to correlate > data and put positions to MAC addresses. > > When an AP is seen on more than one search leg, you should be able to > determine a location based on signal strength in those legs. Where an AP > is seen only on one leg, you can't do as well. > > Could be tested by flying patterns over (or driving by) one's own or > other known APs. Could possibly 'normalize' the antenna pattern of the > receiver. > > This ignores the radiation pattern of AP's antennas, but I dunno what > you could do about that in any case.
Fly real low? But I'm guessing that some antenna-swiveling is a lot easier (and maybe more accurate?) calculation than post-processing a field-strength plot. Maybe not? I'm just handwaving, of course. I have no practical experience in this. Regards, ..jim -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
