Re: How does TCAS get range and bearing?

In article <1hdz3cp9zslvq.bd6inf8tkh7s.dlg@[EMAIL PROTECTED]
>,
 Dallas <Cybnorm@[EMAIL PROTECTED]
> wrote:

> I have never been able to find out how TCAS works and I've asked several
> people.  Today I tried Wikipedia and a couple of other websites, they
were
> no help on the subject.
> 
> It's my belief that TCAS is not a radar system. 

Well, it is a radar system.  It determines RAnge and Direction the same
way
the ATC Beacon Radars do.  The TCAS II system sends out an interrogation,
times the response from the cooperating targets to get range.  Crude
direction 
information is determined by the 4-pole antennea.  This azimuth
information
isn't  particularly accurate (on the order of +/- 15 degrees)

> 
> As I understand it, TCAS gets altitude information directly from the
> interrogated transponder on the target aircraft.   But how does TCAS
gets
> the range and bearing of targets?

-- 
Bob Noel
(goodness, please trim replies!!!)