Difference between revisions of "TrueWind"
(→simplified, assuming H=COG) |
(→simplified, assuming H=COG) |
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* <b>AWA</b> Apparent Wind Angle (relative to H) <b>environment.wind.angleApparent</b> | * <b>AWA</b> Apparent Wind Angle (relative to H) <b>environment.wind.angleApparent</b> | ||
* <b>AWS</b> Apparent Wind Speed <b>environment.wind.speedApparent</b> | * <b>AWS</b> Apparent Wind Speed <b>environment.wind.speedApparent</b> | ||
| − | ** <code> | + | ** <code>AWx = AWS * Cos (AWA)</code> |
| − | ** <code> | + | ** <code>AWy = AWS * Sin (AWA)</code> |
** <b>TWA</b> True Wind Angle (relative to H) <b>environment.wind.angleTrueGround</b> | ** <b>TWA</b> True Wind Angle (relative to H) <b>environment.wind.angleTrueGround</b> | ||
| − | ** <code>ATAN2( | + | ** <code>ATAN2(AWy, -SOG + AWx)</code> |
** <b>TWS</b> True Wind Speed (relative to ground) <b>environment.wind.speedOverGround</b> | ** <b>TWS</b> True Wind Speed (relative to ground) <b>environment.wind.speedOverGround</b> | ||
| − | ** <code>SQRT (POWER( | + | ** <code>SQRT (POWER(AWy,2) POWER(-SOG + AWx,2))</code> |
== see also == | == see also == | ||
Revision as of 08:04, 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
TWSx = SOG * Sin (COG) - AWS * Sin (AWD)TWSy = SOG * Cos (COG) - AWS * Cos (AWD)TWS= SQRT (TWSx*TWSx + TWSy*TWSy)- TWD True Wind Direction (relative to true north) ???
TWD = ATAN ( TWSx / TWSy )
- STW Speed Trough Water navigation.speedThroughWater
- DFT Current Drift (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 (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))
