Data Field Descriptions (JSON and Database)

The following is an explanation of data fields that appear in the JSON files and/or Amazon Redshift database.

  • Id (integer) – “Unique Identifier” of the aircraft, as listed in the VRS basestation.sqb database.  Likely not very useful.  Do not depend on this field, could change.
  • Rcvr (integer) – “Receiver ID number”.  Prior to April 27, 2017, this was always “1”.  After that, it is a unique ID referring to which specific receiver logged the data. Receiver number is 5 to 7 digit integer, with the format of “RRRYXXX” Brief explanation below:
    • RRR – Receiving server.  Could be from 1 – 3 digits.
      • Servers 1-7 are servers that receive load-balanced incoming connections, either in VRS or Beast/RAW format.  Incoming feeds are dynamically assigned to one of these servers, and the receiver ID “XXX” is also dynamically assigned.
      • Server 100 is the “Custom Feed” server, where feeders can send to a specific port and always get the same feeder ID.
    • Y – Type of feed.
      • 1 = Beast/RAW
      • 3 = Compressed VRS
      • 5 = Satellite/Inmarsat/JAERO
      • 6 = Aggregated from a group of receivers
    • XXX – a unique number assigned to feeds.  Static on server 100.  Dynamic on other servers.
  • HasSig (boolean) – True if the aircraft has a signal level associated with it. The level will be included in the “Sig” field.
  • Sig (number) – The signal level for the last message received from the aircraft, as reported by the receiver. Not all receivers pass signal levels. The value’s units are receiver-dependent.
  • Icao (six-digit hex) – One of the most important fields. This is the six-digit hexadecimal identifier broadcast by the aircraft over the air in order to identify itself.  Blocks of these codes are assigned to countries by the International Civil Aviation Organization (ICAO).  Each country then assigns individual codes to aircraft registered in that country. There should generally be a one to one correlation between an aircraft registration number and ICAO hex code.  The ICAO hex identifier can be used to lookup information such as aircraft registration, type, owner/operator, etc in various databases around the internet such as www.airframes.org.  It should be noted that generally the ICAO hex code remains the same as long as the aircraft’s “Registration number” remains the same.  If the registration number changes, which can happen sometimes when an aircraft is sold to an owner in another country, the ICAO hex code will also change.
  • Reg (alphanumeric)Aircraft registration number.  This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • Fseen (datetime – epoch format) – date and time the receiver first started seeing the aircraft on this flight.  Accurate for a single receiver, but as the plane is detected by different receivers, this will change.
  • Tsecs (integer) – The number of seconds that the aircraft has been tracked for.  Will change as aircraft roams between receiving servers.
  • Cmsgs (integer) – The count of messages received for the aircraft.  Will change as aircraft roams between receiving servers.
  • Alt (integer) – The altitude in feet at standard pressure. (broadcast by the aircraft)
  • Galt (integer) – The altitude adjusted for local air pressure, should be roughly the height above mean sea level.
  • InHG (float) – The air pressure in inches of mercury that was used to calculate the AMSL altitude from the standard pressure altitude.
  • AltT (boolean) – The type of altitude transmitted by the aircraft: 0 = standard pressure altitude, 1 = indicated altitude (above mean sea level). Default to standard pressure altitude until told otherwise.
  • Lat (float) – The aircraft’s latitude over the ground.
  • Long (float) – The aircraft’s longitude over the ground.
  • PosTime (epoch milliseconds) – The time (at UTC in JavaScript ticks, UNIX epoch format in milliseconds) that the position was last reported by the aircraft. This field is the time at which the aircraft was at the lat/long/altitude reported above. https://www.epochconverter.com/ may be helpful.
  • Mlat (boolean) – True if the latitude and longitude appear to have been calculated by an MLAT (multilateration) server and were not transmitted by the aircraft. Multilateration is based on the time difference that specific receivers detect the signal and a mathematical calculation.  It is significantly less accurate than ADS-B, which is based on GPS, and more likely to result in jagged aircraft tracks. Aircraft that have Mode S (and have not upgraded to ADS-B) can sometimes be tracked via multilateration.  It requires 3-4 ground stations in different locations to be receiving the aircraft signal simultaneously in order to allow the calculation.
  • TisB (boolean) – True if the last message received for the aircraft was from a TIS-B source.
  • Spd (knots, float) – The ground speed in knots.
  • SpdTyp (integer) – The type of speed that Spd represents. Only used with raw feeds. 0/missing = ground speed, 1 = ground speed reversing, 2 = indicated air speed, 3 = true air speed.
  • Trak (degrees, float) – Aircraft’s track angle across the ground clockwise from 0° north.
  • TrkH (boolean) – True if Trak is the aircraft’s heading, false if it’s the ground track. Default to ground track until told otherwise.
  • Type (alphanumeric) – The aircraft model’s ICAO type code. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • Mdl (string) – A description of the aircraft’s model. Usually also includes the manufacturer’s name. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • Man (string) – The manufacturer’s name. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • Year (integer) – The year that the aircraft was manufactured. This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • Cnum (alphanumeric) – The aircraft’s construction or serial number. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • Op (String) – The name of the aircraft’s operator. This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
  • OpIcao (string) – The ICAO code of the operator.  Non-exhaustive list here: https://en.wikipedia.org/wiki/List_of_airline_codes
  • Sqk (4-digit integer) – Transponder code.  This is a 4-digit code (each digit is from 0-7) entered by the pilot, and typically assigned by air traffic control.  A sqwak code of 1200 typically means the aircraft is operation under VFR and not receiving radar services. 7500 = Hijack code, 7600 = Lost Communications, radio problem, 7700 = Emergency.  More info on codes here: https://en.wikipedia.org/wiki/Transponder_(aeronautics)
  • Vsi (integer) – Vertical speed in feet per minute. Broadcast by the aircraft.
  • VsiT (boolean) – 0 = vertical speed is barometric, 1 = vertical speed is geometric. Default to barometric until told otherwise.
  • WTC (integer) – Wake Turbulence category.  Broadcast by the aircraft.
    • 0 = None
    • 1 = Light
    • 2 = Medium
    • 3 = Heavy
  • Species (integer) – General Aircraft Type. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
    • 0 = None
    • 1 = Land Plane
    • 2 = Sea Plane
    • 3 = Amphibian
    • 4 = Helicopter
    • 5 = Gyrocopter
    • 6 = Tiltwing
    • 7 = Ground Vehicle
    • 8 = Tower
  • EngType (integer) – Type of engine the aircraft uses. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
    • 0 = None
    • 1 = Piston
    • 2 = Turboprop
    • 3 = Jet
    • 4 = Electric
  • EngMount (integer) – The placement of engines on the aircraft. This is looked up via a database based on the ICAO code.  This information is only as good as the database, and is not pulled off the airwaves. It is not broadcast by the aircraft.
    • 0 = Unknown
    • 1 = Aft Mounted
    • 2 = Wing Buried
    • 3 = Fuselage Buried
    • 4 = Nose Mounted
    • 5 = Wing Mounted
  • Engines (alphanumeric) – The number of engines the aircraft has. Usually ‘1’, ‘2’ etc. but can also be a string – see ICAO documentation.
  • Mil (boolean) – True if the aircraft appears to be operated by the military. Based on certain range of ICAO hex codes that the aircraft broadcasts.
  • Cou (string) – The country that the aircraft is registered to.  Based on the ICAO hex code range the aircraft is broadcasting.
  • From (string) – The code and name of the departure airport. Based on user-reported routes, and is quite often wrong.  Don’t depend on it.
  • To (string) – The code and name of the destination airport. Based on user-reported routes, and is quite often wrong.  Don’t depend on it.
  • Gnd (boolean) – True if the aircraft is on the ground. Broadcast by transponder.
  • Call (alphanumeric) – The callsign of the aircraft.  Typically, this can be set by the pilot by entering it into the transponder prior to flight.  Some aircraft simply leave it as their registration number.  Occasionally, you might see “interesting” things (like jokes) entered in this field by the flight crew.
  • CallSus (boolean) – True if the callsign may not be correct. Based on a checksum of the data received over the air.
  • HasPic (boolean) – True if the aircraft has a picture associated with it in the VRS/ADSBexchange database. Pictures often link to http://www.airport-data.com
  • FlightsCount (integer) – The number of Flights records the aircraft has in the database. This value is typically zero based on some internal factors.
  • Interested (boolean) – is the aircraft marked as interesting in the database.
  • Help (boolean) – True if the aircraft is transmitting an emergency sqwak code (i.e. 7700).
  • Trt (integer) – Transponder type – 0=Unknown, 1=Mode-S, 2=ADS-B (unknown version), 3=ADS-B 1, 4=ADS-B 2.
  • TT (string) – Trail type – empty for plain trails, ‘a’ for trails that include altitude, ‘s’ for trails that include speed. This is a Virtual Radar Server parameter and is not a property of the aircraft or transmission.
  • ResetTrail (boolean) – Internal use, do not use.
  • Talt (number) – The target altitude, in feet, set on the autopilot / FMS etc. Broadcast by the aircraft.
  • Ttrk (number) – The track or heading currently set on the aircraft’s autopilot or FMS. Broadcast by the aircraft.
  • Sat (boolean) – True if the data has been received via a SatCom ACARS feed (e.g. a JAERO feed).
  • PosStale (boolean) – True if the last position update is older than the display timeout value – usually only seen on MLAT aircraft in merged feeds. Internal field, basically means that the position data is > 60 seconds old (unless it’s from Satellite ACARS).
  • Source (string) – Internal use only.

Note, ADSBexchange is based on VRS.  Additional info available from VRS website here: http://www.virtualradarserver.co.uk/Documentation/Formats/AircraftList.aspx#response