UAV-1000711-001
Page
25 | 34
The callsign (aka VFR Flight ID) is an 8 character code that corresponds to
the tail number of the aircraft. (0-9, A-Z).
9.4 Aircraft Maximum Speed
Mode S transponders can transmit their maximum airspeed characteristics
to aircraft equipped with TCAS. This information is used to identify threats
and to plan avoiding action by the TCAS equipped aircraft. The airspeeds
are grouped in ranges.
9.5 Aircraft Category
To assist ATC tracking of aircraft, an aircraft category can be transmitted.
9.6 Aircraft V
SO
Groundspeed threshold can be used to help determine and verify the ON
GROUND condition for transmitting ON GROUND message types for “Light
Fixed Wing” aircraft types only.
9.7 Aircraft Size
On the ground, ADS-B transmits encoded aircraft size information which is
used by ATC to identify taxiing routes and potential conflicts. Enter the
length and width (wingspan) fields and the appropriate size codes will be
calculated for transmission.
9.8 GPS Antenna Offset
The GPS antenna offset is used in conjunction with the length and width to
manage taxiway conflicts. A typical GPS does not report the geographic
position of the center of the aircraft, or even the tip of the nose of the
aircraft; instead, it usually reports the location of the actual GPS antenna
(not the GPS receiver). In normal flight operation, this distinction is of no
importance, but if ADS-B is used to manage taxiway conflicts, a significant
offset in antenna position could mean that the aircraft footprint is not in the
same place as the ADS-B reported position. Although the GPS Antenna
Offset is primarily intended for position correction on large transport aircraft,
General Aviation aircraft can also have a significant offset. For example, if
the aircraft has a long tail boom and the GPS antenna is on top of the tail,
the GPS position could be 4 meters or more from the nose of the aircraft.
