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Display the air picture in ForeFlight

See the TAK air picture in your Electronic Flight Bag (EFB). AryaOS runs GDLTAK, which rebroadcasts Cursor on Target (CoT) tracks as GDL90 over UDP, so ForeFlight, FlyQ EFB, and Garmin Pilot display the same traffic TAK sees.

GDLTAK is the reverse of adsbcot: CoT in, GDL90 out. It subscribes to the CoT air picture, keeps a table of tracks, and once a second emits GDL90 Heartbeat, Ownship, and Traffic Report datagrams — exactly as a stratux or GDL 90 receiver would. Any traffic on your TAK network shows up in the cockpit: ADS-B via adsbcot, drone Remote ID via dronecot, even tracks from a TAK Server.

Enabled by the air and multi roles

gdltak is part of the air and multi role unit sets, so selecting either role in Cockpit → AryaOS Site turns it on automatically. See Air — ADS-B & UAT and Device roles.

ForeFlight setup

  1. Put the iPad/iPhone on the same Wi-Fi network as the AryaOS box — join the AryaOS-xxxx hotspot.
  2. That's it. ForeFlight auto-detects GDL90 traffic on UDP port 4000 and lists the source under More → Devices.

Same behavior: join the same Wi-Fi, and the app auto-detects GDL90 traffic on UDP 4000. No manual IP entry needed.

Same Wi-Fi is required

GDLTAK broadcasts GDL90 to 255.255.255.255:4000 by default. Broadcast does not cross subnets, so the EFB device must be on the same Wi-Fi network / L2 segment as the box (e.g. both on the AryaOS hotspot). It is not carried over a routed uplink.

How it flows

flowchart LR
    ADSB[adsbcot / dronecot / TAK Server]
    ADSB -->|Mesh SA<br/>udp+ro://239.2.3.1:6969| G[gdltak]
    G -->|GDL90<br/>udp+broadcast://255.255.255.255:4000| F[ForeFlight / FlyQ / Garmin Pilot]

Configuration

GDLTAK is PyTAK-style, configured via /etc/default/gdltak (systemd EnvironmentFile), inheriting site defaults first:

Key Default Description
COT_URL udp+ro://239.2.3.1:6969 CoT source. Default is the Mesh SA multicast group.
GDL90_URL udp+broadcast://255.255.255.255:4000 GDL90 egress. Broadcast is the stratux/ForeFlight convention; unicast udp://host:port also works.
STALE_SECS 60 Drop tracks not updated within this many seconds.
UPDATE_HZ 1 GDL90 update rate (heartbeat convention is 1 Hz).
OWNSHIP_UID — CoT UID whose track becomes the Ownship Report (e.g. this device's GPSTAK/LINCOT UID).
OWNSHIP_LAT / OWNSHIP_LON / OWNSHIP_ALT_FT — Static ownship position fallback.
CALLSIGN GDLTAK Ownship callsign shown in the EFB.

Ownship

Give the EFB a blue "you are here" ownship in one of two ways:

  • Live: set OWNSHIP_UID to this box's GPSTAK/LINCOT CoT UID so the device's own GPS becomes ownship. See Own position / GPS.
  • Static: set OWNSHIP_LAT / OWNSHIP_LON / OWNSHIP_ALT_FT for a fixed location.

If no ownship is configured, GDLTAK sends heartbeat + traffic only.

Advisory traffic, not certified ADS-B In

CoT carries geometric (HAE) altitude, which GDLTAK uses for the Traffic Report altitude and the Ownship Geometric Altitude message. EFBs treat this as advisory traffic, not certified ADS-B In. Tracks with ICAO-A1B2C3-style UIDs keep their real 24-bit ICAO address; other tracks get a stable self-assigned address hashed from the UID.

Verify

systemctl status gdltak

Then open ForeFlight and confirm traffic appears under More → Devices and on the map. If nothing shows, confirm the EFB device is on the AryaOS hotspot (same subnet) and that traffic exists on the TAK side.