Old 3rd Feb 2019, 08:35
  #983 (permalink)  
DaveReidUK
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 10,565
Originally Posted by ATC Watcher View Post
With a mode S return you can very accurately calculate the ground speed and the final rate of decent
I'm still struggling to understand how that can be so. Can you explain further ?

You said previously that you were talking about Mode S and not ADS-B, but basic Mode S only gives you surveillance ID (squawk) and altitude (DF5 and DF4, respectively).

So, yes, you can calculate RoD, but the download data contains no velocity information so I don't see how it's possible to derive GS.

Originally Posted by ATC Watcher View Post
I noticed the BEA said it will be concentrating the research within 4 square miles, so here you go.
No doubt that's true, but the estimate of final position could well have come from primary radar (possibly military?), rather than SSR.
DaveReidUK is offline