Garmin GDL 88 User Manual
2-4
GDL 88 ADS-B Transceiver Pilot’s Guide
190-01122-03 Rev. A
2.2
Automatic Dependent Surveillance –
Rebroadcast (ADS-R)
Because it is not required that ADS-B In capable aircraft be able to receive
ADS-B data on both the 1090 MHz and 978 MHz data links, a means to get data
from one data link to the other is required. ADS-R is the rebroadcast of ADS-B data
by FAA ground stations and provides this service by taking data from one link and
rebroadcasting it on the other. For example, two aircraft are in the service volume
for a ground station, and one transmitting on 1090 MHz and the other 978 MHz,
the ground station will retransmit the data from each aircraft on the other link to
ensure the two aircraft can “hear” each other.
from one data link to the other is required. ADS-R is the rebroadcast of ADS-B data
by FAA ground stations and provides this service by taking data from one link and
rebroadcasting it on the other. For example, two aircraft are in the service volume
for a ground station, and one transmitting on 1090 MHz and the other 978 MHz,
the ground station will retransmit the data from each aircraft on the other link to
ensure the two aircraft can “hear” each other.
Figure 2-4 ADS-R Operation - FAA Illustration
The GDL 88(D) is capable of receiving ADS-B traffic reports directly on a 1090
MHz data link in addition to traffic reports and FIS-B weather uplinks on the
978 MHz data link. This allows the GDL 88 to directly receive all ADS-B position
reports from aircraft in the vicinity guaranteeing the most complete traffic picture
is available to the flight crew without relying on being within ground station
coverage and ADS-R to provide this complete picture.
978 MHz data link. This allows the GDL 88 to directly receive all ADS-B position
reports from aircraft in the vicinity guaranteeing the most complete traffic picture
is available to the flight crew without relying on being within ground station
coverage and ADS-R to provide this complete picture.