"Sorting Out ADS-B" (February 2019) was a good overview, but readers should be aware that with TIS-B (i.e. where the aircraft position data is derived from retransmitting from a ground station), retransmission will occur either because (i) one aircraft is 1090 ES-equipped, and the other is on 978 or (ii) the threat aircraft is not ADS-B-out-equipped. In either case, the location information displayed (via TIS-B) will be 3 to 13 seconds old. In contrast, where both aircraft are comparably equipped (e.g. both have 978 or both have 1090) location data via ADS-B traffic is practically instantaneous (once per second). I refer you to AIM (section 4-5-8) for further information.
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