satellite-geo-calc

English | 简体中文

This is a tool for satellite positioning related calculations. It mainly provides functions such as space coordinate conversion, dop calculation, GPS time conversion, and Mercator projection coordinate conversion. It can also be used as a reference for related functions.

Please use from v0.0.7

Installation

npm install --save-dev satellite-geo-calc

Usage

Browser

<script src="./node_modules/satellite-geo-calc/dist/bundle.js"></script>

CommonJs

let satellite_geo_calc = require('satellite-geo-calc')

ES module

import satellite_geo_calc from 'satellite-geo-calc'

API

Space coordinate conversion

// coordinate transfer

1. lla to ecef
@param { lon:<Number>, lat:<Number>, alt:<Number> }
satellite_geo_calc.coordinateTransfer.lla_to_ecef(
{ lat: 39.916527, lon: 116.391389, alt: 46 }
)
// output {x: -2177472.7792127146, y: 4388146.268379714, z: 4070910.801458577}

2. ecef to lla
@param { x:<Number>, y:<Number>, z:<Number> }
satellite_geo_calc.coordinateTransfer.ecef_to_lla(
{x: -2177472.7792127146, y: 4388146.268379714, z: 4070910.801458577})
// oupput {lon: 116.391389, lat: 42.0385771807474, alt: 208113.31767852278}

3. enu to ecef
@param1 { x:<Number>, y:<Number>, z:<Number> }
@param2 { lon:<Number>, lat:<Number>, alt:<Number> } reference point lla
satellite_geo_calc.coordinateTransfer.enu_to_ecef(
    {x: 6144810.141746415, y: 1676013.2245262354, z: -5949873.651021555},
    { lat: 39.916527, lon: 116.391389, alt: 46 }
)
// output {x: -5175375.166225361, y: -3394416.3352002986, z: 1538518.83548673}

4. enu to lla
@param1 { x:<Number>, y:<Number>, z:<Number> }
@param2 { lon:<Number>, lat:<Number>, alt:<Number> } reference point lla
satellite_geo_calc.coordinateTransfer.enu_to_lla(
    {x: 6144810.141746415, y: 1676013.2245262354, z: -5949873.651021555},
    { lat: 39.916527, lon: 116.391389, alt: 46 }
)
// output {lon: -146.74, lat: 14.050000000000002, alt: 699.9999999998037}

5. ecef to enu
@param1 { x:<Number>, y:<Number>, z:<Number> }
@param2 { lon:<Number>, lat:<Number>, alt:<Number> } reference point lla
satellite_geo_calc.coordinateTransfer.ecef_to_enu(
    {x: -5175375.166225361, y: -3394416.335200299, z: 1538518.8354867299},
    { lat: 39.916527, lon: 116.391389, alt: 46 }
)
// output {x: 6144810.141746415, y: 1676013.2245262354, z: -5949873.651021555}

6. lla to enu
@param1 { lon:<Number>, lat:<Number>, alt:<Number> }
@param2 { lon:<Number>, lat:<Number>, alt:<Number> } reference point lla
satellite_geo_calc.coordinateTransfer.lla_to_enu(
    { lon:-146.74, lat:14.05,alt:700},
    { lat: 39.916527, lon: 116.391389, alt: 46 }
)
// output {x: 6144810.141746415, y: 1676013.2245262354, z: -5949873.651021555}

Mercator projection coordinate conversion

// mercator transfer

1. mercator transfer
@param { lon:<Number>, lat:<Number>, alt:<Number> }
satellite_geo_calc.mercator.ll_to_mercator({lon:116,lat:47})
// output {x: 12869765.883520856, y: 5922151.4230682505}

Dop calculation

// dop calculate

1. dop calculate
@param array , child is { az:<Number>, el:<Number>} az azimuth angle， el elevation angle
satellite_geo_calc.dop.calc_dop([
{az:45,el:70},{az:65,el:80},{az:250,el:60},{az:300,el:88},{az:180,el:20}
])
// output {pdop: "10.02", hdop: "5.62", gdop: "12.58", vdop: "8.29"}

When the array length < 4 , the calculation is invalid
// output {gdop: "#", pdop: "#", vdop: "#", hdop: "#"}

GPS time calculation

// gps time 

1. unix timestamp to gps time
@param <Number> 10 bits unix timestamp
satellite_geo_calc.gpsweek.u2w(1588139830)
// output {wn: 2104, tow: 309448}

2. gps time to unix timestamp
@param { wn:<Number>, tow:<Number> } gps week，second of week
satellite_geo_calc.gpsweek.w2u({wn: 2104, tow: 309448})
// output 1588744630

Reference

ECEF-LLH-ENU

geodetic-to-ecef