Garmin GDL 88 Series Pilots Guide - Page 14

2.3 Traffic Information Service - Broadcast (TIS-B) TIS-B provides the bridge between the radar based ATC system and the ADS-B based system. When an ADS-B In or Out capable aircraft is within the service volume of an FAA ADS-B ground station, the ground station will begin to broadcast a portion of the ATC radar picture to the aircraft. This aircraft is then included in the list of aircraft that is being provided TIS-B service and is then considered a "TIS-B participant." TIS-B coverage is available when the aircraft is within ground station coverage, in Secondary Surveillance Radar coverage, and the other aircraft is in secondary surveillance radar coverage and transmitting altitude. ATC radar tracks for other aircraft within ±3,500 feet and 15 NM of the participant is provided by the ground station, to include altitude, position, ground speed, and ground track. TIS-B data is broadcast once every three to thirteen seconds depending on the characteristics of the FAA radar ground station. Figure 2-5 TIS-B Operation - FAA Illustration NOTE: Even if the display is showing TIS-B traffic, unless the TIS-B participant indication is present (see Section 2.1) , TIS-B services are not being provided specific to your aircraft and the traffic picture may not be complete. 2-4 Garmin GDL 84/88 ADS-B Transceiver Pilot's Guide 190-01122-03 Rev. E