Initial data validity ages in "track.c"

I am trying to understand the reasoning behind the “stale” and “expire” values and in particular why altitude_baro, squawk and airground have a stale value of 15 while all others are 60 - can someone please explain?

It’s fairly arbitrary, but the idea is that we should be receiving frequent updates to those three, and they are readily available from both Mode S and ADS-B (“stale” mostly controls when dump1090 is willing to drop to a less reliable data source i.e. ADS-B to Mode S)

thank for the inside, I will play with higher numbers then …