Difference between revisions of "TrueWind"
(→calculate True Wind from Apparent Wind) |
(→calculate True Wind from Apparent Wind) |
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** <code>TWD = ATAN ( TWx / TWy )</code> | ** <code>TWD = ATAN ( TWx / TWy )</code> | ||
* <b>STW</b> Speed Trough Water <b>navigation.speedThroughWater</b> | * <b>STW</b> Speed Trough Water <b>navigation.speedThroughWater</b> | ||
| − | ** <b>DFT</b> Current Drift (relative to ground) <b>environment.current.drift</b> | + | ** <b>DFT</b> Current Drift (speed relative to ground) <b>environment.current.drift</b> |
** <code>DFTx = SOG * Sin (COG) - STW * Sin (H)</code> | ** <code>DFTx = SOG * Sin (COG) - STW * Sin (H)</code> | ||
** <code>DFTy = SOG * Cos (COG) - STW * Cos (H)</code> | ** <code>DFTy = SOG * Cos (COG) - STW * Cos (H)</code> | ||
** <code>DFT= SQRT (DFTx*DFTx + DFTy*DFTy)</code> | ** <code>DFT= SQRT (DFTx*DFTx + DFTy*DFTy)</code> | ||
| − | ** <b>SET</b> Current Set (relative to true north) <b>environment.current.setTrue</b> | + | ** <b>SET</b> Current Set (direction relative to true north) <b>environment.current.setTrue</b> |
** <code>SET = ATAN ( DFTx / DFTy )</code> | ** <code>SET = ATAN ( DFTx / DFTy )</code> | ||
Revision as of 08:09, 30 October 2018
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 Current Drift (speed relative to ground) environment.current.drift
DFTx = SOG * Sin (COG) - STW * Sin (H)DFTy = SOG * Cos (COG) - STW * Cos (H)DFT= SQRT (DFTx*DFTx + DFTy*DFTy)- SET Current Set (direction relative to true north) environment.current.setTrue
SET = ATAN ( DFTx / DFTy )
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))
