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.