From 16f1d450ae714f029d2d175765e7cff4fef227c3 Mon Sep 17 00:00:00 2001 From: Oliver Jowett Date: Thu, 2 May 2019 22:15:32 +0800 Subject: [PATCH] Some corrections to json doc updates --- README-json.md | 54 ++++++++++++++++++++++---------------------------- 1 file changed, 24 insertions(+), 30 deletions(-) diff --git a/README-json.md b/README-json.md index 3a5e10b..d5c7a91 100644 --- a/README-json.md +++ b/README-json.md @@ -37,16 +37,23 @@ This file contains dump1090's list of recently seen aircraft. The keys are: * 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 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). - * type: type of the modeS address e.g. ADS-B, ADR-R, TIS-B + * 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 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 either feet or meters - * alt_geom: geometric (GNSS / INS) altitude in either feet or meters + * 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 + * 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 @@ -54,46 +61,33 @@ This file contains dump1090's list of recently seen aircraft. The keys are: * 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, useful for ADS-B report correlation with SSR data - * emergency: provide asdditional information regarding aircraft status (2.2.3.2.7.8.1.1) - * category: emitter category to identify particular aircraft or vehicle types (values A0 - D7) (2.2.3.2.5.2) - - Set A: - 1 Light, 2 Small, 3 Large, 4 High Vortex Large, 5 Heavy, 6 High Performance, 7 Rotorcraft - - Set B: - 1 Glider,2 Lighter than Air, 3 Parachutist, 4 Ultralight, 6 Unmanned Areal Vehicel, 7 Space/Transatmospheric vehicle - - Set C: - 1 Emergency Vehicle, 2 Service Vehicle, 3..5 Obstruction - - Set D: Reserved - * nav_qnh: altimeter setting (QFE or QNH/QNE), millibars + * 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: target state and status with 'autopilot', 'vnav', 'althold', 'approach', 'lnav', 'tcas' + * 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, (Rc) - is the radius that there is a 95% probability the aircraft is within that radius of its stated position, - both horizontally and vertically. + * 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) - probability of the reported horizontal position exceeding the radius of containment defined by the NIC - * sil_type: unknown, perHour, perSample + * 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 based on MLAT e.g. 'lat', 'lon', 'nic', 'rc', 'nac_v' - * tisb: ??? list of fields based on TIS-B ??? + * 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. - removed fields: - * vert_rate: vertical rate in feet/minute - * speed: reported speed in kt. This is usually speed over ground, but might be IAS - you can't tell the difference here, sorry! - * nucp: the NUCp (navigational uncertainty category) reported for the position - +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