node-sbs1

This is a node.js module that parses ASCII messages containing Mode S ADS-B aircraft data that is in "SBS-1 BaseStation port 30003" format. This format has become a semi-standard way of sending ADS-B data.

SBS-1 messages are in a simple comma-delimited format. Here are some examples of the messages this module parses:

SEL,,496,2286,4CA4E5,27215,2010/02/19,18:06:07.710,2010/02/19,18:06:07.710,RYR1427
ID,,496,7162,405637,27928,2010/02/19,18:06:07.115,2010/02/19,18:06:07.115,EZY691A
AIR,,496,5906,400F01,27931,2010/02/19,18:06:07.128,2010/02/19,18:06:07.128
STA,,5,179,400AE7,10103,2008/11/28,14:58:51.153,2008/11/28,14:58:51.153,RM
CLK,,496,-1,,-1,2010/02/19,18:18:19.036,2010/02/19,18:18:19.036
MSG,1,145,256,7404F2,11267,2008/11/28,23:48:18.611,2008/11/28,23:53:19.161,RJA1118,,,,,,,,,,,
MSG,2,496,603,400CB6,13168,2008/10/13,12:24:32.414,2008/10/13,12:28:52.074,,,0,76.4,258.3,54.05735,-4.38826,,,,,,0
MSG,3,496,211,4CA2D6,10057,2008/11/28,14:53:50.594,2008/11/28,14:58:51.153,,37000,,,51.45735,-1.02826,,,0,0,0,0
MSG,4,496,469,4CA767,27854,2010/02/19,17:58:13.039,2010/02/19,17:58:13.368,,,288.6,103.2,,,-832,,,,,
MSG,5,496,329,394A65,27868,2010/02/19,17:58:12.644,2010/02/19,17:58:13.368,,10000,,,,,,,0,,0,0
MSG,6,496,237,4CA215,27864,2010/02/19,17:58:12.846,2010/02/19,17:58:13.368,,33325,,,,,,0271,0,0,0,0
MSG,7,496,742,51106E,27929,2011/03/06,07:57:36.523,2011/03/06,07:57:37.054,,3775,,,,,,,,,,0
MSG,8,496,194,405F4E,27884,2010/02/19,17:58:13.244,2010/02/19,17:58:13.368,,,,,,,,,,,,0

There's some documentation of the message format at http://woodair.net/SBS/Article/Barebones42_Socket_Data.htm

Here are some examples of using the module:

// Parse a string containing an SBS1 message.
var sbs1 = require('sbs1');
var s = 'MSG,3,496,211,4CA2D6,10057,2008/11/28,14:53:50.594,2008/11/28,14:58:51.153,,37000,,,51.45735,-1.02826,,,0,0,0,0';
var msg = sbs1.parseSbs1Message(s);
if (msg.message_type === sbs1.MessageType.TRANSMISSION &&
    msg.transmission_type === sbs1.TransmissionType.ES_AIRBORNE_POS) {
  console.log('coords: ' + msg.lat + ', ' + msg.lon);
}

// Connect to a server at localhost:30003 that is sending messages in SBS1
// format.  You can pass an options object containing host and port to
// createClient to connect to a different server/port.
var sbs1 = require('sbs1');
var client = sbs1.createClient();
client.on('message', function(msg) {
  if (msg.message_type === sbs1.MessageType.TRANSMISSION &&
      msg.transmission_type === sbs1.TransmissionType.ES_AIRBORNE_POS) {
    console.log('coords: ' + msg.lat + ', ' + msg.lon);
  }
});

Parsed messages

Parsed messages have the following fields:

|Field |Description | |-----------------|---------------------------------------------------------------------| |message_type |See MessageType. | |transmission_type|See TransmissionType. | |session_id |String. Database session record number. | |aircraft_id |String. Database aircraft record number. | |hex_ident |String. 24-bit ICACO ID, in hex. | |flight_id |String. Database flight record number. | |generated_date |String. Date the message was generated. | |generated_time |String. Time the message was generated. | |logged_date |String. Date the message was logged. | |logged_time |String. Time the message was logged. | |callsign |String. Eight character flight ID or callsign. | |altitude |Integer. [Mode C] 1 Altitude relative to 1013 mb (29.92" Hg). | |ground_speed |Integer. Speed over ground. | |track |Integer. Ground track angle. | |lat |Float. Latitude. | |lon |Float. Longitude | |vertical_rate |Integer. Climb rate. | |squawk |String. Assigned [Mode A] 1 squawk code. | |alert |Boolean. Flag to indicate that squawk has changed. | |emergency |Boolean. Flag to indicate emergency code has been set. | |spi |Boolean. Flag to indicate Special Position Indicator has been set. | |is_on_ground |Boolean. Flag to indicate ground squat switch is active. |

Not all message/transmission types will have values for all fields. Missing values will be represented by null or undefined (an empty comma-delimited value is null).

Parsed messages have generated_timestamp() and logged_timestamp() methods that parse the corresponding date and time fields and return Date objects.

MessageType

There are 6 types of SBS-1 messages represented by the MessageType enum:

|Enum |Value | |------------------|--------| |SELECTION_CHANGE|"SEL" | |NEW_ID |"ID" | |NEW_AIRCRAFT |"AIR" | |STATUS_AIRCRAFT |"STA" | |CLICK |"CLK" | |TRANSMISSION |"MSG" |

SELECTION_CHANGE, NEW_ID, NEW_AIRCRAFT, STATUS_CHANGE, and CLK indicate changes in the state of the SBS-1 software and aren't typically used by other systems.

TRANSMISSION messages contain information sent by aircraft.

TransmissionType

There are 8 subtypes of transmission messages, specified by the TransmissionType enum:

|Enum |Value|Description |Spec | |-----------------------|-----|-------------------------------|------------| |ES_IDENT_AND_CATEGORY|1 |ES identification and category |DF17 BDS 0,8| |ES_SURFACE_POS |2 |ES surface position message |DF17 BDS 0,6| |ES_AIRBORNE_POS |3 |ES airborne position message |DF17 BDS 0,5| |ES_AIRBORNE_VEL |4 |ES airborne velocity message |DF17 BDS 0,9| |SURVEILLANCE_ALT |5 |Surveillance alt message |DF4, DF20 | |SURVEILLANCE_ID |6 |Surveillance ID message |DF5, DF21 | |AIR_TO_AIR |7 |Air-to-air message |DF16 | |ALL_CALL_REPLY |8 |All call reply |DF11 |

Only ES_SURFACE_POS and ES_AIRBORNE_POS transmissions will have position (latitude and longitude) information.