ABSTRACT
The development of Mode S has led onto two
related systems: traffic alert and collision
avoidance systems (TCAS) and automatic
dependent surveillance-broadcast (ADS-B). Both
systems can exchange data directly between
aircraft. TCAS is a surveillance system that
provides warnings directly to the crew when other
navigation systems (including ATC) have failed
to maintain safe separation of aircraft. ADS-B is
an emerging technology for air traffic
management (ATM) that is intended to replace
conventional secondary surveillance radar. TCAS
is addressed in the Chapter 22; ADS-B is
described below.
