The output is list of recently seen aircraft.
Status information:
- msg: Shows if there is an error, default is “No error”.
- now: The time this file was generated, in seconds since Jan 1 1970 00:00:00 GMT (the Unix epoch)
- total: Total aircraft returned.
- ctime: The time this file was cached, in seconds since Jan 1 1970 00:00:00 GMT (the Unix epoch).
- ptime: The server processing time this request required in milliseconds.
For each aircraft object, the following are shown if available.
- now: the time this file was generated, in seconds since Jan 1 1970 00:00:00 GMT (the Unix epoch).
- messages: the total number of Mode S messages processed since readsb started.
- aircraft: an array of JSON objects, one per known aircraft. Each aircraft has the following keys. Keys will be omitted if data is not available.
- hex: the 24-bit ICAO identifier of the aircraft, as 6 hex digits. The identifier may start with ‘~’, this means that the address is a non-ICAO address (e.g. from TIS-B).
- type: type of underlying messages / best source of current data for this position / aircraft: (the following list is in order of which data is preferentially used)
- adsb_icao: messages from a Mode S or ADS-B transponder, using a 24-bit ICAO address
- adsb_icao_nt: messages from an ADS-B equipped “non-transponder” emitter e.g. a ground vehicle, using a 24-bit ICAO address
- adsr_icao: rebroadcast of ADS-B messages originally sent via another data link e.g. UAT, using a 24-bit ICAO address
- tisb_icao: traffic information about a non-ADS-B target identified by a 24-bit ICAO address, e.g. a Mode S target tracked by secondary radar
- adsc: ADS-C (received by monitoring satellite downlinks)
- mlat: MLAT, position calculated arrival time differences using multiple receivers, outliers and varying accuracy is expected.
- other: miscellaneous data received via Basestation / SBS format, quality / source is unknown.
- mode_s: ModeS data from the planes transponder (no position transmitted)
- adsb_other: messages from an ADS-B transponder using a non-ICAO address, e.g. anonymized address
- adsr_other: rebroadcast of ADS-B messages originally sent via another data link e.g. UAT, using a non-ICAO address
- tisb_other: traffic information about a non-ADS-B target using a non-ICAO address
- tisb_trackfile: traffic information about a non-ADS-B target using a track/file identifier, typically from primary or Mode A/C radar
- flight: callsign, the flight name or aircraft registration as 8 chars (2.2.8.2.6)
- r: aircraft registration pulled from database
- t: aircraft type pulled from database
- dbFlags: military and interesting bitwise & pulled from database
- 1: mil
- 2: interesting
- 3: both
- alt_baro: the aircraft barometric altitude in feet
- alt_geom: geometric (GNSS / INS) altitude in feet referenced to the WGS84 ellipsoid
- gs: ground speed in knots
- ias: indicated air speed in knots
- tas: true air speed in knots
- mach: Mach number
- track: true track over ground in degrees (0-359)
- track_rate: Rate of change of track, degrees/second
- roll: Roll, degrees, negative is left roll
- mag_heading: Heading, degrees clockwise from magnetic north
- true_heading: Heading, degrees clockwise from true north (usually only transmitted on ground, in the air usually derived from the magnetic heading using magnetic model WMM2020)
- baro_rate: Rate of change of barometric altitude, feet/minute
- geom_rate: Rate of change of geometric (GNSS / INS) altitude, feet/minute
- squawk: Mode A code (Squawk), encoded as 4 octal digits
- emergency: ADS-B emergency/priority status, a superset of the 7×00 squawks (2.2.3.2.7.8.1.1)
- category: emitter category to identify particular aircraft or vehicle classes (values A0 – D7) (2.2.3.2.5.2)
- nav_qnh: altimeter setting (QFE or QNH/QNE), hPa
- nav_altitude_mcp: selected altitude from the Mode Control Panel / Flight Control Unit (MCP/FCU) or equivalent equipment
- nav_altitude_fms: selected altitude from the Flight Manaagement System (FMS) (2.2.3.2.7.1.3.3)
- nav_heading: selected heading (True or Magnetic is not defined in DO-260B, mostly Magnetic as that is the de facto standard) (2.2.3.2.7.1.3.7)
- nav_modes: set of engaged automation modes: ‘autopilot’, ‘vnav’, ‘althold’, ‘approach’, ‘lnav’, ‘tcas’
- lat, lon: the aircraft position in decimal degrees
- nic: Navigation Integrity Category (2.2.3.2.7.2.6)
- rc: Radius of Containment, meters; a measure of position integrity derived from NIC & supplementary bits. (2.2.3.2.7.2.6, Table 2-69)
- seen_pos: how long ago (in seconds before “now”) the position was last updated
- track: true track over ground in degrees (0-359)
- version: ADS-B Version Number 0, 1, 2 (3-7 are reserved) (2.2.3.2.7.5)
- nic_baro: Navigation Integrity Category for Barometric Altitude (2.2.5.1.35)
- nac_p: Navigation Accuracy for Position (2.2.5.1.35)
- nac_v: Navigation Accuracy for Velocity (2.2.5.1.19)
- sil: Source Integity Level (2.2.5.1.40)
- sil_type: interpretation of SIL: unknown, perhour, persample
- gva: Geometric Vertical Accuracy (2.2.3.2.7.2.8)
- sda: System Design Assurance (2.2.3.2.7.2.4.6)
- mlat: list of fields derived from MLAT data
- tisb: list of fields derived from TIS-B data
- messages: total number of Mode S messages received from this aircraft
- seen: how long ago (in seconds before “now”) a message was last received from this aircraft
- rssi: recent average RSSI (signal power), in dbFS; this will always be negative.
- alert: Flight status alert bit (2.2.3.2.3.2)
- spi: Flight status special position identification bit (2.2.3.2.3.2)
- wd, ws: wind direction, wind speed: calculated from ground track, true heading, true airspeed and ground speed
- oat, tat: outer air temperate, total air temperature: calculated from mach number and true airspeed (typically somewhat inaccurate at lower altitudes / mach numbers below 0.5)
Section references (2.2.xyz) refer to DO-260B.