FlightAware Discussions

How does FA count positions?

For yesterday (8 Apr 2019), OpenSky says I reported 61,136,062 Mode S messages, of which 15,291,778 were Extended Squitter, of which 5,744,721 were Airborne Position and 5,756,120 were Airborne Velocity. That seems to match up with typical message rates and position rates I see in SkyView locally, though I’m just eyeballing that.

However, my FA stats page says I reported only 811,284 positions on the same day–an order of magnitude lower than what OpenSky says. What’s with the discrepancy?

FWIW, the number of aircraft is usually within ~5%, which seems to rule out a lot of likely problems.

Aircraft position is sent to flightaware only once every 5 seconds for planes below 10000 ft and every 10 seconds for planes above 10000 ft.
That’s what the position count is derived from.
Or something along those lines, i’ve tried searching but i can’t find the post on the topic that i’m thinking of.

OpenSky takes a lot more network bandwidth because every ModeS message is sent verbatim to opensky, they also store evert one of them i believe.