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

[TLE]: http://en.wikipedia.org/wiki/Two-line_element_set
[NORAD]: http://en.wikipedia.org/wiki/NORAD
[NASA]: http://en.wikipedia.org/wiki/NASA
[SGP4]: http://en.wikipedia.org/wiki/SGP4
[SDP4]: http://en.wikipedia.org/wiki/SDP4

Install via npm

``sh
$ 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

`js
var TLE = require( 'tle' )
`

$3

`js
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'
`

`js
var tle = TLE.parse( set )
`

`js
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,
}
`

$3

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

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

$3

`js
// 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}' )
`

`js
// 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
``