AIS Stream Decoder

AIS/NMEA decoder with native stream interface for Node.js.

Installation

This is a Node.js module available through the npm registry.

Installation is done using the npm install command:

$ npm install ais-stream-decoder

Features

• Currently supports message types 1,2,3,4,5,18,24 (more to come) and partially supports message type 8 (inland static and voyage data)
• Handles multi-part messages out of the box
• Streaming API implemented as a Node.js transform stream
• Returns nicely formatted JSON messages
• Written in TypeScript

Usage

Decode a single line of data:

import AisDecoder from 'ais-stream-decoder';

const aisDecoder = new AisDecoder();
aisDecoder.on('error', err => console.error(err));
aisDecoder.on('data', decodedMessage => console.log(decodedMessage));

const nmea = '!AIVDM,1,1,,B,133i;RPP1DPEbcDMV@1r:Ow:2>`<,0*41';
aisDecoder.write(nmea);

=>

{"type":1,"channel":"B","repeat":0,"mmsi":205278090,"navStatus":0,"rateOfTurn":null,"speedOverGround":8.4,"accuracy":true,"lon":4.73319,"lat":51.725665,"courseOverGround":260.1,"heading":null,"utcSecond":37,"specialManoeuvre":0,"raim":true,"radio":59916,"sentences":["!AIVDM,1,1,,B,133i;RPP1DPEbcDMV@1r:Ow:2>`<,0*41"]}

Handles multi-part messages like a pro:

import AisDecoder from 'ais-stream-decoder';

const aisDecoder = new AisDecoder();
aisDecoder.on('error', err => console.error(err));
aisDecoder.on('data', decodedMessage => console.log(decodedMessage));

const part1 =
  '!AIVDM,2,1,7,A,57lof8`2F5HeT<eC:204e86373:222222222221@8HQC16Ch0:RA7kAD,0*28';
const part2 = '!AIVDM,2,2,7,A,PBp888888888880,2*79';

aisDecoder.write(part1);
aisDecoder.write(part2);

=>

{"type":5,"channel":"A","repeat":0,"mmsi":525200930,"aisVersion":2,"imo":9835915,"callsign":"YCKT2","name":"AKRA 102","typeAndCargo":80,"dimBow":67,"dimStern":33,"dimPort":19,"dimStarboard":1,"epfd":1,"etaMonth":9,"etaDay":7,"etaHour":16,"etaMinute":0,"draught":4.2,"destination":"ID_MERAK","dte":false,"sentences":["!AIVDM,2,1,7,A,57lof8`2F5HeT<eC:204e86373:222222222221@8HQC16Ch0:RA7kAD,0*28","!AIVDM,2,2,7,A,PBp888888888880,2*79"]}

Use it to read and decode NMEA line-by-line from a file:

import AisDecoder from 'ais-stream-decoder';
import {createReadStream} from 'fs';
import {resolve} from 'path';
import {createInterface} from 'readline';

const aisDecoder = new AisDecoder();
aisDecoder.on('error', err => console.error(err));
aisDecoder.on('data', decodedMessage => console.log(decodedMessage));

const fileStream = createReadStream(
  resolve(__dirname, './examples/messages.txt')
);
const readLine = createInterface(fileStream);
readLine.on('line', line => aisDecoder.write(line));

We all love pipes! ❤

import AisDecoder from 'ais-stream-decoder';
import split from 'split';
import {createReadStream} from 'fs';
import {resolve} from 'path';

const fileStream = createReadStream(
  resolve(__dirname, './examples/messages.txt')
);
const aisDecoder = new AisDecoder({silent: true});

fileStream
  .pipe(split())
  .pipe(aisDecoder)
  .on('data', decodedMessage => {
    console.log(decodedMessage);
  });

License

MIT