diff --git a/README-json.md b/README-json.md index b6599aa..d5c7a91 100644 --- a/README-json.md +++ b/README-json.md @@ -38,19 +38,56 @@ This file contains dump1090's list of recently seen aircraft. The keys are: * messages: the total number of Mode S messages processed since dump1090 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). - * squawk: the 4-digit squawk (octal representation) - * flight: the flight name / callsign - * lat, lon: the aircraft position in decimal degrees - * nucp: the NUCp (navigational uncertainty category) reported for the position - * seen_pos: how long ago (in seconds before "now") the position was last updated - * altitude: the aircraft altitude in feet, or "ground" if it is reporting it is on the ground - * vert_rate: vertical rate in feet/minute + * type: type of underlying message, one of: + * 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 + * 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) + * 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) - * speed: reported speed in kt. This is usually speed over ground, but might be IAS - you can't tell the difference here, sorry! + * 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 + * 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 7x00 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: selected altitude + * nav_heading: selected heading + * 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 + * 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. - + +Section references (2.2.xyz) refer to DO-260B. + ## history_0.json, history_1.json, ..., history_119.json These files are historical copies of aircraft.json at (by default) 30 second intervals. They follow exactly the