Difference between revisions of "TrueWind"

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=== Wind ===
 
=== Wind ===
 +
* <b>AWS</b> Apparent Wind Speed <b>environment.wind.speedApparent</b>
 +
* <b>AWD</b> Apparent Wind Direction (relative to true north) <b>environment.wind.directionTrue</b>
 +
* <b>AWD</b> Apparent Wind Direction (relative to magnetic north) <b>environment.wind.directionMagnetic</b>
 +
* <b>AWA</b> Apparent Wind Angle (relative to H) <b>environment.wind.angleApparent</b>
 +
 +
* <b>TWS</b> True Wind Speed (relative to ground) <b>environment.wind.speedOverGround</b>
 +
* <b>TWS</b> True Wind Speed (relative to water) <b>environment.wind.speedTrue</b>
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* <b>TWD</b> True Wind Direction (relative to true north) <b>???</b>
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* <b>TWA</b> True Wind Angle (relative to H)
 +
** Description: True wind angle based on speed over ground, negative to port <b>environment.wind.angleTrueGround</b>
 +
** Description: True wind angle based on speed through water, negative to port <b>environment.wind.angleTrueWater</b>
  
 
=== Current ===
 
=== Current ===

Revision as of 12:58, 30 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.courseOverGroundTrue
  • STW Speed Trough Water navigation.speedThroughWater
  • H Heading (relative to true north) navigation.headingTrue
  • H Heading (relative to magnetic north) navigation.headingMagnetic
  • DFT Drift (drifting speed relative to ground) ???
  • SET Set (drifting direction relative to true north) ???

Wind

  • AWS Apparent Wind Speed environment.wind.speedApparent
  • AWD Apparent Wind Direction (relative to true north) environment.wind.directionTrue
  • AWD Apparent Wind Direction (relative to magnetic north) environment.wind.directionMagnetic
  • AWA Apparent Wind Angle (relative to H) environment.wind.angleApparent
  • TWS True Wind Speed (relative to ground) environment.wind.speedOverGround
  • TWS True Wind Speed (relative to water) environment.wind.speedTrue
  • TWD True Wind Direction (relative to true north) ???
  • TWA True Wind Angle (relative to H)
    • Description: True wind angle based on speed over ground, negative to port environment.wind.angleTrueGround
    • Description: True wind angle based on speed through water, negative to port environment.wind.angleTrueWater

Current

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

calculate True Wind from Apparent Wind

  • AWA Apparent Wind Angle (relative to H) environment.wind.angleApparent
  • H 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
    • TWS True Wind Speed (relative to ground) environment.wind.speedOverGround
    • TWx = SOG * Sin (COG) - AWS * Sin (AWD)
    • TWy = SOG * Cos (COG) - AWS * Cos (AWD)
    • TWS= SQRT (TWx*TWx + TWy*TWy)
    • TWD True Wind Direction (relative to true north) ???
    • TWD = ATAN ( TWx / TWy )
  • STW Speed Trough Water navigation.speedThroughWater
    • DFT Drift (speed relative to ground) ???
    • DFTx = SOG * Sin (COG) - STW * Sin (H)
    • DFTy = SOG * Cos (COG) - STW * Cos (H)
    • DFT= SQRT (DFTx*DFTx + DFTy*DFTy)
    • SET Set (direction relative to true north) ???
    • SET = ATAN ( DFTx / DFTy )

True+True+Wind.jpg

simplified, assuming H=COG

  • COG Course Over Ground navigation.courseOverGroundTrue
  • SOG Speed Over Ground navigation.speedOverGround
  • AWA Apparent Wind Angle (relative to H) environment.wind.angleApparent
  • AWS Apparent Wind Speed environment.wind.speedApparent
    • AWx = AWS * Cos (AWA)
    • AWy = AWS * Sin (AWA)
    • TWA True Wind Angle (relative to H) environment.wind.angleTrueGround
    • ATAN2(AWy, -SOG + AWx)
    • TWS True Wind Speed (relative to ground) environment.wind.speedOverGround
    • SQRT (POWER(AWy,2) POWER(-SOG + AWx,2))

True+True+Wind2.jpg


Sensors

Heading

SOG and COG

  • GPS receiver

STW

AWS and AWA