ATC Radar Question

"Peter Dohm" wrote in message
.. .
"Matt Barrow" wrote in message

In other words how does the radar know that the aircraft is actually 3 nm
away laterally and not 4.25 nm (approx slant distance at that altitude)?

Asquared + B squared = C squared, I'd guess.


And how does it separate A and B?

"A" is the radar range, "B" is garnered from the encoding altimiter.



Interesting thread!

But, for the life of me, I can't figure any reason that atc would really care
about the exact map location of an aircraft--especially when it is both close
enough and high enough for the error to be significant.

Given the two most common uses, surveilance approaches to an airport at nearly
the same elevation as the radar and collision avoidance, the map distance
should be a trivial issue.


Given the effort put into the significantly more accurate WAAS infrastructure,
I'd suspect that getting a more accurate fix would be correspondingly desirable.