Garmin GTS 825 Pilots Guide - Page 21

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 displayed 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. 190-00587-02 Rev. A Garmin GTS 8XX Series Traffic Advisory System 17