The Federal Aviation Administration (FAA)
has gained some significant early operational
experience with the Traffic Information Service
Broadcast (TIS-B), both on the East Coast of the
United States, and in the Anchorage, Alaska area.
TIS-B, for the first time, puts geo-referenced radar
data directly in the cockpit where, for a number of
reasons, the customer can be more sensitive to
inaccuracy and other anomalies than the traditional
user (i.e., the air traffic controller).
The Broadcast of Automatic Dependent
Surveillance (ADS-B) is the air-to-air transmission
of aircraft position and velocity information. In
order for ground surveillance radar data and ADS-B
data to integrate seamlessly in the cockpit, a "truly
geo-referenced" radar alignment technique is
needed for radar to ADS-B correlation. Successful
synergy between ADS-B and radar requires accrued
radar registration. Incorrect geo-referencing can
result in a number of anomalies that can be difficult
for both designers and pilots to deal with
appropriately.
This paper describes the process of georeferencing
radar data, describes some real world
limitations of the radar sensors, the anomalies that
can be encountered and their cause, techniques for
mitigating these anomalies, and finally, this paper
discusses one of the radar alignment techniques
used for the system providing TIS-B in Anchorage
for the FAA's Capstone program.
This paper will attempt to bridge the gap
between the ground systems and airborne systems.
Given the insight into the processing performed on
the ground, the avionics developers may adapt or
create new ways to overcome these issues.
