User manual
Garrecht Avionik GmbH TRX-1500 ADS-B Traffic Monitor User Manual
Revision: 1.0a 11 31 JAN 2012
1.5. Transponder signals, FLARM® signals and system behaviour
Different transponder signals (ADS-B, Mode-S Replies, Mode-S Squitters) result in different system
reaction. The table below shows the different signals and the related reactions.
1.5.1. Mode-S Extended Squitter with ADS-B out
Broadcasted by
Mode-S Transponder equipped aircraft WITH connected GPS
Broadcast interval 1 /sek.
System reactions
TRX-1500
Output of aircraft’s position and altitude data via system interfaces according to
interface configuration.
Output of warnings (violating the protection volume, collision warning)
A warning is always focussing the most dangerous aircraft.
FLARM® Warnings always have higher priority. If an aircraft is equipped with
FLARM® and ADS-B out, only FLARM® warnings will be processed
1.5.2. Mode-S Squitter
Broadcasted by
Mode-S Transponder equipped aircraft WITHOUT connected GPS
Broadcast interval 1 /sek.
System reactions
TRX-1500
Detecting of horizontal approximation (analyzing the signal strength).
Alitude information will not be processed.
1.5.3. Mode-S Replies
Broadcasted by Mode-S Transponder equipped aircraft, which are interrogated by radar
ground station or TCAS
Broadcast interval Depending on external interrogation, every 4-6 sek.
System reactions
TRX-1500
Detecting of horizontal approximation (analyzing the signal strength)
Detecting of vertical approximation (processing the coded altitude signals)
1.5.4. FLARM®
Broadcasted by FLARM® equipped aircraft
Broadcast interval 1 /sek.
System reactions
TRX-1500
Output of aircraft’s position and altitude data via system interfaces according
to interface configuration
Output of warnings (collision or proximity warning). Output of distance,
direction, vertical distance.
A warning always indicates the most dangerous target.
FLARM® Warnings always have higher priority. If an aircraft is equipped with
FLARM® and ADS-B out, only FLARM® warnings will be processed










