Garmin GTS 855 - Manual (Page 21)

17 190-00587-02 Rev. A Garmin GTS 8XX Series Traffic Advisory System
Q AND A
What are the benefits of ADS-B?
1090 MHz Extended Squitter ADS-B data contains additional information
about a target aircraft including flight ID, latitude, longitude, barometric and
geometric altitude, velocity, and direction.
This provides precise location information about the target aircraft. Targets
within the active surveillance range that are correlated with ADS-B data are dis-
played with much greater accuracy as a result of this.
When is ADS-B (passive surveillance) available?
Passive surveillance functionality is available when the GTS 8XX system is
installed with an ADS-B link transmit class of equipment. Target aircraft must
be equipped with a 1090 MHz ADS-B transmit class unit to provide ADS-B data
for passive surveillance.
How do we correlate the ADS-B data with the TAS/TCAS I data?
The GTS 8XX Series correlates TAS or TCAS I range, altitude, and bearing data
with internally received 1090 Extended Squitter ADS-B data when available, using
the precision information from ADS-B to determine the location of the target.
The TAS/TCAS I data, either correlated, or uncorrelated if target aircraft is
not equipped with an ADS-B transmitter, is sent to a display such as a G600 or
G1000 Control/Display Unit, GNS 430, GNS 480, GNS 530, MX 20, GMX 200,
or a third-party device.
How are active and passive targets displayed?
For systems that use Garmin’s High-Speed Data Bus (HSDB) to communicate
data to the display device, correlated targets will be shown with their flight ID. A
future update will include the display of track and velocity information, as well as
ground targets. Passive surveillance targets outside the active surveillance range
will also be displayed with their flight ID.
For systems that use ARINC 429 to communicate data to the display device,
ARINC 429 protocol does not exist to distinguish between correlated targets
and uncorrelated targets. For this reason only active surveillance correlated and
uncorrelated targets will be transmitted to the display device with no distinction
between the two, but with enhanced position accuracy derived from the correlated
data. Display characteristics that would distinguish the passive (ADS-B) and active
targets would require a software update to the display device.