JsPredict

A Javascript port of the popular predict satellite tracking library.

$3

- PREDICT: http://www.qsl.net/kd2bd/predict.html
- PyPredict: https://github.com/nsat/pypredict
- Python-SGP4: https://github.com/brandon-rhodes/python-sgp4

$3

- Satellite.js: https://github.com/shashwatak/satellite-js
- Moment.js: https://github.com/moment/moment

Installation

JsPredict has been pushed to the NPM, Meteor (Atmosphere), and Bower package registries, and can also be used by including the src file directly.

$3

``
npm install jspredict
`

$3

`
meteor add rosh93:jspredict
`

$3

`
bower install jspredict
`

$3

Download and include moment.js: http://momentjs.com/

Include both satellite.js and jspredict.js to get satellite and jspredict available on the global window namespace.

API

#### Input Types

`js
tle = 3 line string with "\n" character line breaks

qth = 3 element array [latitude (degrees), longitude (degrees), altitude (km)]

time, start, or end = unix timestamp (ms) or date object "new Date()"
`

#### Methods

`js
observe(tle 'required', qth 'optional', time 'optional')

observes(tle 'required', qth 'optional', start 'optional', end 'required', interval 'optional')

transits(tle 'required', qth 'required', start 'optional', end 'required', minElevation 'optional', maxTransits 'optional')
`

Examples

$3

`js
> var tle = '0 LEMUR-2 JEROEN\n1 40934U 15052E 15306.10048119 .00001740 00000-0 15647-3 0 9990\n2 40934 6.0033 141.2190 0010344 133.6141 226.4604 14.76056230 5130';
> var jspredict = require('jspredict');
> jspredict.observe(tle, null);
{ eci:
{ position:
{ x: 6780.217861682045,
y: -1754.945569075624,
z: -382.1001487529574 },
velocity:
{ x: 1.8548312182745958,
y: 7.28225574805238,
z: -0.6742937006920255 } },
gmst: 1.2743405900207918,
latitude: -3.141891992384467,
longitude: -87.52591692501754,
altitude: 635.9975103859342,
footprint: 5474.178485006438 }
`

$3

`js
> var tle = '0 LEMUR-2 JEROEN\n1 40934U 15052E 15306.10048119 .00001740 00000-0 15647-3 0 9990\n2 40934 6.0033 141.2190 0010344 133.6141 226.4604 14.76056230 5130';
> var qth = [15, 130, .1];
> jspredict.observe(tle, qth);
{ eci:
{ position:
{ x: 6808.890168241923,
y: -1638.1745052042197,
z: -392.83171494347425 },
velocity:
{ x: 1.729088700801128,
y: 7.313653076194647,
z: -0.6671038712037236 } },
gmst: 1.275507328110315,
latitude: -3.2301661539920232,
longitude: -86.6090669346031,
altitude: 636.124394452163,
footprint: 5474.682764305541,
azimuth: 75.42118188269167,
elevation: -70.0809770796008,
rangeSat: 12666.306550391646,
doppler: 1.0000075435881037 }
`

$3

`js
> var tle = '0 LEMUR-2 JEROEN\n1 40934U 15052E 15306.10048119 .00001740 00000-0 15647-3 0 9990\n2 40934 6.0033 141.2190 0010344 133.6141 226.4604 14.76056230 5130';
> var qth = [15, 130, .1];
> jspredict.transits(tle, qth, 1446516345242, 1446545135046, 2, 4);
[ { start: 1446519623929.2715,
end: 1446520436786.1265,
maxElevation: 26.592307317708126,
apexAzimuth: 173.44894443969358,
maxAzimuth: 244.2708297009277,
minAzimuth: 108.07476128814045,
duration: 812856.8549804688 },
{ start: 1446525901933.6611,
end: 1446526693580.5254,
maxElevation: 24.777958881102588,
apexAzimuth: 170.71484739848532,
maxAzimuth: 244.97838417889344,
minAzimuth: 110.85020906380568,
duration: 791646.8642578125 },
{ start: 1446532176864.1306,
end: 1446533027054.9875,
maxElevation: 20.48579856021555,
apexAzimuth: 194.49205827738396,
maxAzimuth: 242.43145831257118,
minAzimuth: 114.97146874644389,
duration: 850190.8569335938 },
{ start: 1446538461828.8735,
end: 1446539183964.2942,
maxElevation: 15.359176537330036,
apexAzimuth: 188.34763284223402,
maxAzimuth: 236.24036969182643,
minAzimuth: 123.49296057832372,
duration: 722135.4206542969 } ]
>
``