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3

ADS-B is more accurate. SSR calculates the distance to a target based on when it receives a reply from the transponder, which is inherently imprecise, and calculates the azimuth by the sweep, which is also inherently imprecise. A blip on a radar scope isn't exactly where the plane is but rather the center of an area where the plane is most likely to be. ...


2

In case of imminent danger remember these three words: aviate, navigate communicate. In that order. Aviate: make sure you keep flying the aircraft, and keep it flying in one piece. Navigate: know what is around you and control where you are going. Avoid crashing into anything or anyone else. Communicate: let ATC and/or other aircraft know what your ...


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I think the problem is that you see a Mode 3/A (identity) reply, but you try to interpret it as Mode C (altitude reply). In Mode C, altitude is Gillham encoded, using all pulses except for D1 and X. This gives a range of -1200 to 126700 ft in 100 ft increments. If you see a D1 pulse, you are not looking at a Mode C reply. In Mode A, a 12 bit identity (...


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ADS-B has two defined datalinks, 1090ES and UAT978. UAT978 is, so far, only available in the US. FIS-B is weather radar and similar data, and is only available on UAT978. 1090ES datalink is an enhancement to Mode S that adds DF17 messages with position, velocity and other ADS-B data. TIS-B is a ground-based service that transmits ADS-B-like messages on ...


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All the recorded transmissions you have, seem to come from the same aircraft. They come all from the onboard (Mode-S) transponder. All transmission with Downlink Format (DF) 17 are ADS-B. Those with DF18 are TIS-B (or ADS-R), you don't have any of these (they are rare in Europe, and more common in the US) Mode-S uses the following DF's: DF4 - altitude ...


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