at.adsb.datalink.message

{
  "$type": "com.atproto.lexicon.schema",
  "defs": {
    "groundStationInfo": {
      "description": "Identification of the ground station involved in the datalink communication.",
      "properties": {
        "id": {
          "description": "Ground station identifier (e.g. HFDL station ID, VDL2 ground station address).",
          "maxLength": 32,
          "type": "string"
        },
        "location": {
          "description": "Geographic position of the ground station.",
          "ref": "community.lexicon.location.geo",
          "type": "ref"
        },
        "name": {
          "description": "Human-readable ground station name (e.g. 'Shannon', 'Reykjavik').",
          "maxGraphemes": 64,
          "maxLength": 640,
          "type": "string"
        }
      },
      "type": "object"
    },
    "main": {
      "description": "A captured aircraft datalink message.",
      "key": "tid",
      "record": {
        "properties": {
          "callsign": {
            "description": "Flight callsign as identified in the message.",
            "maxLength": 8,
            "type": "string"
          },
          "capturedAt": {
            "description": "When the message was received by the station.",
            "format": "datetime",
            "type": "string"
          },
          "createdAt": {
            "format": "datetime",
            "type": "string"
          },
          "frequencyMhz": {
            "description": "Frequency the message was received on, in MHz (e.g. '131.550').",
            "maxLength": 20,
            "type": "string"
          },
          "groundStation": {
            "description": "Ground station involved in the communication, if identifiable.",
            "ref": "#groundStationInfo",
            "type": "ref"
          },
          "icaoHex": {
            "description": "ICAO 24-bit aircraft address in hexadecimal, if identifiable.",
            "maxLength": 6,
            "type": "string"
          },
          "label": {
            "description": "ACARS message label (two-character code indicating message type).",
            "maxLength": 2,
            "type": "string"
          },
          "messageText": {
            "description": "Decoded message content.",
            "maxGraphemes": 2048,
            "maxLength": 20480,
            "type": "string"
          },
          "position": {
            "description": "Aircraft position at the time of the message, if included.",
            "ref": "at.adsb.flight.defs#position",
            "type": "ref"
          },
          "protocol": {
            "description": "Datalink protocol the message was received on.",
            "knownValues": [
              "at.adsb.datalink.message#acars",
              "at.adsb.datalink.message#vdl2",
              "at.adsb.datalink.message#hfdl"
            ],
            "maxLength": 256,
            "type": "string"
          },
          "receiverDid": {
            "description": "DID of the receiver that captured this message.",
            "format": "did",
            "type": "string"
          },
          "registration": {
            "description": "Aircraft registration, if identifiable from the message.",
            "maxLength": 10,
            "type": "string"
          },
          "sublabel": {
            "description": "ACARS sublabel for further message classification.",
            "maxLength": 4,
            "type": "string"
          }
        },
        "required": [
          "protocol",
          "capturedAt",
          "createdAt"
        ],
        "type": "object"
      },
      "type": "record"
    }
  },
  "description": "A captured aircraft datalink message (ACARS, VDL2, or HFDL). These are low-volume, high-value records that represent individual communications between aircraft and ground stations.",
  "id": "at.adsb.datalink.message",
  "lexicon": 1
}