TrueWind is a small library for converting apparent wind to true wind.
Thank yous for code and math goes to these brilliant authors:
- https://kingtidesailing.blogspot.com/2015/10/correcting-nmea-0183-wind-for-vessel.html
- http://sailboatinstruments.blogspot.com/2011/05/true-wind-vmg-and-current-calculations.html
npm install --save @gml/truewind
const TrueWind = require("@gml/truewind");
console.log(
TrueWind.getTrue({
aws: 10, // Apparent wind speed (kt or m/s)
awa: 34, // Apparent wind angle (deg -180 - 180)
bspd: 5.9, // Boat speed as measured (kt or m/s)
sog: 5.7, // Speed over ground (kt or m/s)
cog: 14, // Course over ground (deg true)
heading: 8, // Boat heading (deg magnetic, including deviation)
variation: 5, // Magnetic variation
roll: -5, // Boat heeling (deg, - to port, + to starboard) [optional]
pitch: -2, // Boat pitch (deg, - bow up, + bow down) [optional]
K: 10, // Leeway coefficient, see [1] [optional]
speedunit: "kt" // Unit of bspd, needed for leeway [optional]
})
);
/* Expected output
{
awa: 34.0851339452323,
aws: 10.016144980963647,
leeway: -1.4363688595231254,
stw: 5.901854481278832,
vmg: 2.128531457191982,
tws: 6.239378683682382,
twa: 67.4232233531618,
twd: 80.4232233531618,
soc: 1.2725741359616143,
doc: 116.85441404030568
} */
// [1] http://sailboatinstruments.blogspot.com/2011/02/leeway-calibration.html
MIT