On Mon, 17 Feb 2014 14:57:44 +0000 Allan Healy allan.healy121@gmail.com wrote:
My name is Allan an I am currently working on my final year project for college. The idea is to create a radar system that interprets MODE C interrogation signals and replies by aircraft and SSR and with this information determine where these airplanes are in your vicinity.
I never heard of anyone being able to do that so far. Mode S is easy and there's any number of 1090 Extended Squitter receivers and decoders out there, but Mode C relies on the illumination by the radar to trigger the transmission. Since you cannot know where the radar is pointing and when the impulse started (and sometimes not where the radar is located), you cannot link Mode C squitter with the particular primary target.
You can receive Mode C with rtl_adsb and have a look at 56-bit packets, but they are completely useless for an independent ground station.
Some people nowadays play with a concept of building a something like interferometer from 3 or 4 receivers, but nobody has succeeded thus far, as far as I know.
-- Pete