node-tle's Introduction

Two-line element set (TLE)

Two-line element set (TLE) data format parser

A two-line element set (TLE) is a data format used to convey sets of orbital elements that describe the orbits of Earth-orbiting satellites. A computer program called a model can use the TLE to compute the position of a satellite at a particular time. The TLE is a format specified by NORAD and used by NORAD and NASA. The TLE can be used directly by the SGP4 model (or one of the SGP8, SDP4, SDP8 models). Orbital elements are determined for many thousands of space objects by NORAD and are freely distributed on the Internet in the form of TLEs. A TLE consists of a title line followed by two lines of formatted text.

— From Wikipedia

Install via npm

$ npm install --save tle

Format

More, detailed information is available at NASA Human Space Flight:

Some data to play around with can be found at Celestrak and in Celestrak's Master Index.

Usage

var TLE = require( 'tle' )

Parsing a single set

var set = 'ISS (ZARYA)\n' +
  '1 25544U 98067A   08264.51782528 -.00002182  00000-0 -11606-4 0  2927\n' +
  '2 25544  51.6416 247.4627 0006703 130.5360 325.0288 15.72125391563537'

var tle = TLE.parse( set )

TLE {
  name: 'ISS (ZARYA)',
  number: 25544,
  class: 'U',
  id: '98067A',
  date: Date<'2008-09-20T12:25:40.104Z'>,
  fdmm: -0.00002182,
  sdmm: 0,
  drag: -0.000011606,
  ephemeris: 0,
  esn: 292,
  inclination: 51.6416,
  ascension: 247.4627,
  eccentricity: 0.0006703,
  perigee: 130.536,
  anomaly: 325.0288,
  motion: 15.72125391,
  revolution: 56353,
}

Parsing a stream

var parser = new TLE.Parser( options ) // OR
var parser = TLE.createParser( options )

fs.createReadStream( FILEPATH )
  .pipe( new TLE.Parser() )
  .on( 'data', function( tle ) {
    // ...
  })

Creating a TLE instance from existing data

// From a JSON string
var tle = TLE.fromJSON( '{"name":"ISS (ZARYA)","number":25544,"class":"U","id":"98067A","date":"2008-09-20T12:25:40.104Z","fdmm":-0.00002182,"sdmm":0,"drag":-0.000011606,"ephemeris":0,"esn":292,"inclination":51.6416,"ascension":247.4627,"eccentricity":0.0006703,"perigee":130.536,"anomaly":325.0288,"motion":15.72125391,"revolution":56353}' )

// From an object
var tle = TLE.fromJSON({
  name: 'FENGYUN 1C DEB',
  class: 'U',
  id: '29740',
})

Speed

It can read, stream & parse ~2500 TLEs from the file system in about 100ms.

node example/fs-stream.js
Parser: 2517 TLEs, 108ms, 23306 op/s
Parser: 23 op/ms

Examples

See examples folder for runnable examples:

node examples/fs-stream.js
node examples/http-stream.js

node-tle's People

Contributors

Stargazers

Watchers

node-tle's Issues

Broken link to TLE definition from spaceflight.nasa.gov

It appears https://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP_Help/tle_def.html has moved or died

Drag value is incorrect

I think you need to add a '0.' prefix to the drag term before calling 'parseFloat'.

According to the docs: (67960-4 = 0.000067960)

I'd be happy to create a PR.

Motion and Revolution are incorrect

Is this project still maintained?

I believe there is an error with the parsing for the motion and revolution properties. Per the docs and wikipedia motion is 11 columns long from columns 53-63 (1-indexed) and revolution is 5 columns long from columns 64-68 (1-indexed).

Given the ISS example of

'ISS (ZARYA)\n' +
  '1 25544U 98067A   08264.51782528 -.00002182  00000-0 -11606-4 0  2927\n' +
  '2 25544  51.6416 247.4627 0006703 130.5360 325.0288 15.72125391563537'

motion should be 15.72125391 but instead is 15.721253915
revolution should be 56353 but instead is 6353

If needed I can fork and submit a pull request for this.

Thanks.

Recommend Projects

jhermsmeier / node-tle Goto Github PK