Difference between revisions of "TrueWind"
(→simplified, assuming H=COG) |
|||
| Line 1: | Line 1: | ||
| + | == see also == | ||
| + | * http://davidburchnavigation.blogspot.com/2013/04/true-true-wind-from-apparent-wind.html | ||
| + | * https://coaps.fsu.edu/woce/truewind/paper/index.html | ||
| + | * http://signalk.org/specification/1.0.0/doc/otherBranches.html | ||
| + | |||
| + | == Terms == | ||
| + | |||
| + | === vessel's Movement and Orientation === | ||
| + | * <b>SOG</b> Speed Over Ground <b>navigation.speedOverGround</b> | ||
| + | * <b>COG</b> Course Over Ground (relative to true north)<b>navigation.courseOverGroundTrue</b> | ||
| + | * <b>COG</b> Course Over Ground (relative to magnetic north)<b>navigation.courseOverGroundTrue</b> | ||
| + | * <b>STW</b> Speed Trough Water <b>navigation.speedThroughWater</b> | ||
| + | * <b>H</b> Heading (relative to true north) <b>navigation.headingTrue</b> | ||
| + | * <b>H</b> Heading (relative to magnetic north) <b>navigation.headingMagnetic</b> | ||
| + | * <b>DFT</b> Drift (drifting speed relative to ground) <b>???</b> | ||
| + | * <b>SET</b> Set (drifting direction relative to true north) <b>???</b> | ||
| + | |||
| + | === Wind === | ||
| + | |||
| + | === Current === | ||
| + | * <b>???</b> Drift caused by current (speed relative to ground) <b>environment.current.drift</b> | ||
| + | * <b>???</b> Current Set (direction relative to true north) <b>environment.current.setTrue</b> | ||
| + | * <b>???</b> Current Set (direction relative to magnetic north) <b>environment.current.setMagnetic</b> | ||
| + | |||
== calculate True Wind from Apparent Wind == | == calculate True Wind from Apparent Wind == | ||
* <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> | ||
| Line 15: | Line 39: | ||
** <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> | + | ** <b>DFT</b> Drift (speed relative to ground) <b>???</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> | + | ** <b>SET</b> Set (direction relative to true north) <b>???</b> |
** <code>SET = ATAN ( DFTx / DFTy )</code> | ** <code>SET = ATAN ( DFTx / DFTy )</code> | ||
http://2.bp.blogspot.com/-5xrObeSQIUI/UXWPPH_BzrI/AAAAAAAABTI/DOQB0TQ_69Y/s1600/True+True+Wind.jpg | http://2.bp.blogspot.com/-5xrObeSQIUI/UXWPPH_BzrI/AAAAAAAABTI/DOQB0TQ_69Y/s1600/True+True+Wind.jpg | ||
| Line 36: | Line 60: | ||
http://1.bp.blogspot.com/-MeBJW4WFKu8/UXWPPPk0w_I/AAAAAAAABTM/iuky5duX4kk/s1600/True+True+Wind2.jpg | http://1.bp.blogspot.com/-MeBJW4WFKu8/UXWPPPk0w_I/AAAAAAAABTM/iuky5duX4kk/s1600/True+True+Wind2.jpg | ||
| − | + | ||
| − | |||
| − | |||
== Sensors == | == Sensors == | ||
Revision as of 12:41, 30 October 2018
Contents
see also
- http://davidburchnavigation.blogspot.com/2013/04/true-true-wind-from-apparent-wind.html
- https://coaps.fsu.edu/woce/truewind/paper/index.html
- http://signalk.org/specification/1.0.0/doc/otherBranches.html
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
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 )
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))
Sensors
Heading
- see also http://www.navlab.net/Publications/The_Seven_Ways_to_Find_Heading.pdf
- magnetic compass
- H true = H magnetic + Magnetic declination
- Fluxgate compass
- H true = H magnetic + Magnetic declination
- Gyrocompass
- H true
- moving baseline Real-time kinematic (GPS)
- H true
SOG and COG
- GPS receiver
STW
AWS and AWA
- wind-vane (AWA)
- anemometer
- cup (AWS)
- hand held propeller (AWS)
- ultrasonic (AWS and AWA)
