This python program is a simple program to read traffic from the json port of a ADSB tracker such as that provided by running an ADSBExchange raspberry pi image. It communicates with the readsb.service to get json records about any aircraft within a configured distance of the receiving station.
To find the port it is publishing on, utilize:
sudo systemctl status readsb.service
and you will get back something like:
readsb.service - readsb ADS-B receiver
Loaded: loaded (/etc/systemd/system/readsb.service; enabled; vendor preset: enabled)
Active: active (running) since Mon 2024-01-08 04:00:07 MST; 10h ago
Docs: https://github.com/mictronics/readsb
Main PID: 471 (readsb)
Tasks: 11 (limit: 3720)
CPU: 1h 17min 19.089s
CGroup: /system.slice/readsb.service
└─471 /usr/bin/readsb --net-api-port 30152 --net-json-port 30154 --write-prom /run/readsb/stats.pr>
Jan 08 04:00:07 adsbexchange readsb[471]: 30154: Position json output port
Jan 08 04:00:07 adsbexchange readsb[471]: 30003: SBS TCP output ALL port
Jan 08 04:00:07 adsbexchange readsb[471]: 30001: Raw TCP input port
Jan 08 04:00:07 adsbexchange readsb[471]: 30004: Beast TCP input port
Jan 08 04:00:07 adsbexchange readsb[471]: 30104: Beast TCP input port
Jan 08 04:00:07 adsbexchange readsb[471]: 30152: API output port
the --net-json-port is the one that this script wants to connect to.
The script will connect to the specified MQTT server and send any received ADSB packets to the MQTT server. It further enhances these packets by adding in a photo of the plane from plane spotters API so that an image of the approaching aircraft can be displayed.
MAX_DISTANCE - The distance in nautical miles within which a plane must pass before publishing the data
READ_ADSB_SERVICE_ADDR - The IP address of the adsb tracker
READ_ADSB_SERVICE_PORT - The port on which the json service is attached to (see above)
MQTT_SERVER_ADDR - The IP address of the MQTT server to publish packets to
MQTT_SERVER_PORT - The port on which the MQTT server is listening
MQTT_TOPIC - The topic on which the results should be published