Configuration Reference

All fields in /etc/deskradar/config.json.

Example of Config File

{
  "LAT": 50,
  "LON": 0,
  "GET_URL": "http://127.0.0.1:8080/data/aircraft.json",
  "MATRIX_HTTP_URL": "http://10.42.0.50",
  "LCD_SEND_URL": "http://0.0.0.0:8010/display",
  "MATRIX_SIZE_PX": 64,
  "DISPLAY_RADIUS_NM": 25,
  "MAX_HISTORY": 20,
  "POLL_CADENCE": 1,
  "FADE_FACTOR": 0.95,
  "MIN_ALT": 1000,
  "UNSEEN_MARK_SECS": 10,
  "MAX_UNSEEN_SECS": 20,
  "LONLAT_DECIMALS": 3,
  "MATRIX_HTTP_TIMEOUT": 2,
  "LCD_TIMEOUT": 1,
  "SHOW_CLOSEST": true,
  "CLOSEST_COLOUR": {"r": 255, "g": 255, "b": 255},
  "LOG_LEVEL": "info"
}

Location

Key	Type	Default	Description
`LAT`	float	50	Latitude of the display center in decimal degrees.
`LON`	float	0	Longitude of the display center in decimal degrees.

Network URLs

Key	Type	Default	Description
`GET_URL`	string	`http://127.0.0.1:8080/data/aircraft.json`	dump1090 API endpoint to poll for aircraft data. Usually local to the Pi.
`MATRIX_HTTP_URL`	string	set by boot_check	Base URL of the MatrixPortal S3. Written automatically at boot by resolving `deskradar-portal.local`. The boot check writes `http://<ip>:80`; the checked-in example value is only a startup placeholder.
`LCD_SEND_URL`	string	`http://0.0.0.0:8010/display`	URL of the LCD service endpoint. Points to the local deskradar-lcd FastAPI service.

GET_URL, LCD_SEND_URL, and MATRIX_HTTP_URL are hidden from the web configurator UI because they are managed by the system.

Display

Key	Type	Default	Description
`MATRIX_SIZE_PX`	int	64	Pixel dimensions used by the Pi for plotting. The current MatrixPortal firmware is hardcoded for a 64x64 display, so this should remain 64 unless the firmware is changed too for now!
`DISPLAY_RADIUS_NM`	int	25	Radius of the displayed area in nautical miles, centered on `LAT`/`LON`. Aircraft beyond this radius are not shown.
`SHOW_CLOSEST`	bool	true	Controls matrix recoloring for the head of the nearest current aircraft when more than one aircraft is present. The current LCD closest-aircraft display is not gated by this flag.
`CLOSEST_COLOUR`	object	`{"r":255,"g":255,"b":255}`	RGB color used to highlight the closest aircraft. Must include `r`, `g`, and `b` keys with values 0-255.

Tracking

Key	Type	Default	Description
`MAX_HISTORY`	int	20	Maximum number of historical position points retained per aircraft track.
`POLL_CADENCE`	float	1	Seconds between polling cycles.
`FADE_FACTOR`	float	0.95	Multiplier applied to trail point colors each cycle (0.0-1.0). 0.95 means each point's brightness drops by 5% per second at 1-second cadence. Lower values fade trails faster.
`MIN_ALT`	int	1000	Minimum altitude in feet for an aircraft to appear on screen. Filters out ground traffic and very-low-altitude aircraft.
`MAX_UNSEEN_SECS`	int	20	Seconds after the latest point before the track begins timing out. When this threshold is exceeded, the app pops one old point per cycle, marks the visible head red, and fades the trail.

Timeouts

Mostly debug stuff this

Key	Type	Default	Description
`MATRIX_HTTP_TIMEOUT`	int	2	Seconds before HTTP requests to the MatrixPortal time out. Should be less than `POLL_CADENCE` to avoid blocking the loop.
`LCD_TIMEOUT`	int	1	Seconds before HTTP requests to the LCD service time out.

Logging

Key	Type	Default	Allowed Values
`LOG_LEVEL`	string	`"info"`	`debug`, `info`, `warning`, `error`, `critical` (case-insensitive)