Difference between revisions of "TrueWind"

From wiki.bastelbude.grade.de
Jump to: navigation, search
((calculate current))
(calculate True Wind from Apparent Wind)
Line 50: Line 50:
 
* <b>COG</b> Course Over Ground <b>navigation.courseOverGroundTrue</b>
 
* <b>COG</b> Course Over Ground <b>navigation.courseOverGroundTrue</b>
 
* <b>SOG</b> Speed Over Ground <b>navigation.speedOverGround</b>
 
* <b>SOG</b> Speed Over Ground <b>navigation.speedOverGround</b>
** <b>TWS</b> True Wind Speed (relative to ground) <b>environment.wind.speedOverGround</b>
+
** <b>GWS</b> Ground Wind Speed <b>environment.wind.speedOverGround</b>
** <code>TWx = OGx - AWx = SOG * Sin (COG) - AWS * Sin (AWD)</code>
+
** <code>GWx = OGx - AWx = SOG * Sin (COG) - AWS * Sin (AWD)</code>
** <code>TWy = OGy - AWy = SOG * Cos (COG) - AWS * Cos (AWD)</code>
+
** <code>GWy = OGy - AWy = SOG * Cos (COG) - AWS * Cos (AWD)</code>
** <code>TWS= SQRT (TWx*TWx  + TWy*TWy)</code>
+
** <code>GWS= SQRT (TWx*TWx  + TWy*TWy)</code>
 
** <b>TWD</b> True Wind Direction (relative to true north) <b>???</b>
 
** <b>TWD</b> True Wind Direction (relative to true north) <b>???</b>
** <code>TWD = ATAN ( TWx / TWy )</code>
+
** <code>GWD = ATAN ( GWx / GWy )</code>
  
 
[[File:Wind_1.jpg|500px]]
 
[[File:Wind_1.jpg|500px]]

Revision as of 13:55, 31 October 2018

see also

Terms

vessel's Movement and Orientation

  • SOG Speed Over Ground navigation.speedOverGround
  • COG Course Over Ground (relative to true north) navigation.courseOverGroundTrue
  • COG Course Over Ground (relative to magnetic north) navigation.courseOverGroundMagnetic
  • STW Speed Trough Water navigation.speedThroughWater
  • HDG Heading
    • HDT Heading (relative to true north) navigation.headingTrue
    • HDM Heading (relative to magnetic north) navigation.headingMagnetic

Wind

  • AW Apparent Wind (relative to vessel)
    • AWS Apparent Wind Speed environment.wind.speedApparent
    • AWD Apparent Wind Direction (relative to true north) environment.wind.directionTrue directionApparantTrue
    • AWD Apparent Wind Direction (relative to magnetic north) environment.wind.directionMagnetic directionApparantMagnetic
    • AWA Apparent Wind Angle (relative to HDG) environment.wind.angleApparent
  • TW True Wind (relative to surface of the water)
    • TWS True Wind Speed environment.wind.speedTrue speedWater
    • TWD True Wind Direction (relative to true north) add: environment.wind.directionWaterTrue
    • TWD True Wind Direction (relative to magnetic north) add: environment.wind.directionWaterMagnetic
    • TWA True Wind Angle (relative to HDG) environment.wind.angleTrueWater angleWater
  • GW Ground Wind (relative to ground) used in weather forecasts and reports
    • GWS Ground Wind Speed environment.wind.speedOverGround
    • GWD Ground Wind Direction (relative to true north) add: environment.wind.directionOverGroundTrue
    • GWD Ground Wind Direction (relative to magnetic north) add: environment.wind.directionOverGroundMagnetic
    • GWA Ground Wind Angle (relative to HDG) environment.wind.angleTrueGround angleOverGround

Current

  • DFT Current Drift (speed relative to ground) environment.current.drift
  • SET Current Set (direction relative to true north) environment.current.setTrue
  • SET Current Set (direction relative to magnetic north) environment.current.setMagnetic

calculate True Wind from Apparent Wind

  • AWA Apparent Wind Angle (relative to HDG) environment.wind.angleApparent
  • HDT Heading (relative to true north) navigation.headingTrue
    • AWD Apparent Wind Direction (relative to true north) environment.wind.directionTrue
    • AWD = MOD(H+AWA;360)
  • AWS Apparent Wind Speed environment.wind.speedApparent
  • COG Course Over Ground navigation.courseOverGroundTrue
  • SOG Speed Over Ground navigation.speedOverGround
    • GWS Ground Wind Speed environment.wind.speedOverGround
    • GWx = OGx - AWx = SOG * Sin (COG) - AWS * Sin (AWD)
    • GWy = OGy - AWy = SOG * Cos (COG) - AWS * Cos (AWD)
    • GWS= SQRT (TWx*TWx + TWy*TWy)
    • TWD True Wind Direction (relative to true north) ???
    • GWD = ATAN ( GWx / GWy )

Wind 1.jpg

(calculate current)

  • COG Course Over Ground navigation.courseOverGroundTrue
  • SOG Speed Over Ground navigation.speedOverGround
  • HDT Heading (relative to true north) navigation.headingTrue
  • STW Speed Trough Water in direction of HDG
    • DFT Drift (current speed relative to ground) environment.current.drift
    • DFTx = OGx - SHx = SOG * Sin (COG) - S * Sin (HDT)
    • DFTy = OGy - SHy = SOG * Cos (COG) - S * Cos (HDT)
    • DFT= SQRT (DFTx*DFTx + DFTy*DFTy)
    • SET Set (current direction relative to true north) environment.current.setTrue
    • SET = ATAN ( DFTx / DFTy )

signalk-derived-data groundWind.js

  • https://github.com/SignalK/signalk-derived-data/blob/master/calcs/groundWind.js
  • SOG Speed Over Ground navigation.speedOverGround
  • AWA Apparent Wind Angle (relative to HDG) environment.wind.angleApparent
  • AWS Apparent Wind Speed environment.wind.speedApparent
    • AWx = AWS * Cos (AWA)
    • AWy = AWS * Sin (AWA)
    • GWA Ground Wind Angle (relative to HDG) environment.wind.angleTrueGround
    • GWA = ATAN2(AWy, -SOG + AWx)
    • GWS Ground Wind Speed (relative to ground) environment.wind.speedOverGround
    • GWS = SQRT (POWER(AWy,2) POWER(-SOG + AWx,2))

signalk-derived-data windDirection.js

  • https://github.com/SignalK/signalk-derived-data/blob/master/calcs/windDirection.js
  • HDG Heading
    • HDT Heading (relative to true north) navigation.headingTrue
    • HDM Heading (relative to magnetic north) navigation.headingMagnetic
  • AWA Apparent Wind Angle (relative to HDG) environment.wind.angleApparent
    • AWD Apparent Wind Direction
      • environment.wind.directionTrue
      • environment.wind.directionMagnetic
    • AWD = HDG + AWA
      if (AWD > Math.PI * 2) AWD -= Math.PI * 2
      else if (AWD < 0) AWD += Math.PI * 2

Sensors

Heading

SOG and COG

  • GPS receiver

STW

AWS and AWA