fr.cnes.sirius.patrius.attitudes.directions

Class StellarAberrationCorrection

java.lang.Object

fr.cnes.sirius.patrius.attitudes.directions.StellarAberrationCorrection

public final class StellarAberrationCorrection
extends Object

This class implements the stellar aberration correction for both reception and transmission cases.

Nota: The light-time aberration is out of the scope of this class.

Since:

4.10

Author:

Alice Latourte

Method Summary

Modifier and Type	Method and Description
static Vector3D	applyInverseTo(PVCoordinatesProvider transmitter, Vector3D transmitterToTargetDir, Frame frame, AbsoluteDate date) Return the direction in which the signal should be emitted to reach the Target due to stellar aberration. Warning: The Observer transmits the signal to the target.
static Vector3D	applyTo(PVCoordinatesProvider observer, Vector3D observerToTargetDir, Frame frame, AbsoluteDate date) Return the Target apparent direction from Observer position due to stellar aberration. The Observer receives the signal emitted by the Target.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

applyTo

public static Vector3D applyTo(PVCoordinatesProvider observer,
                               Vector3D observerToTargetDir,
                               Frame frame,
                               AbsoluteDate date)
                        throws PatriusException

Return the Target apparent direction from Observer position due to stellar aberration.
The Observer receives the signal emitted by the Target.

Relativistic effects are not taken into account here.

              target    target(corrected)
                T          T'
               ^          ^
              /         .
             /        .  dir(corrected)
            /__ Δθ  .
       dir /   \  .
          /     .
         /    .
        /   .
       /__.
      / . \  θ
     /.    |
     -----------> _
   O              V
  observer     velocity
 
                  (V/c)sin(θ)
  sin(Δθ) = ------------------------- ≈ (V/c)sin(θ) + 1/2(V/c)²sin(2θ)
            sqrt(1 + 2(V/c) + (V/c)²)
 
 (non-relativistic case)
 
 Note:
 In the solar system
      V/c       ≈ 1e-4 or 1e-2 deg
      1/2(V/c)² ≈ 1e-8 or 1e-6 deg
 Only the first term is taken into account here

 

Parameters:

observer - provider of Observer PV coordinates

observerToTargetDir - light-time corrected direction from Observer to Target

frame - expression frame of the entered observerToTargetDir

date - computation date of the entered observerToTargetDir (observer date)

Returns:

Apparent Observer-Target direction corrected for stellar aberration

Throws:

PatriusException - if solar system ephemerides cannot be loaded

applyInverseTo

public static Vector3D applyInverseTo(PVCoordinatesProvider transmitter,
                                      Vector3D transmitterToTargetDir,
                                      Frame frame,
                                      AbsoluteDate date)
                               throws PatriusException

Return the direction in which the signal should be emitted to reach the Target due to stellar aberration.
Warning: The Observer transmits the signal to the target.

Relativistic effects are not taken into account here.

     target(corrected)  target
                   T'    T
                   ^    ^
                  .    /
                  __Δθ/
  dir(corrected) .  \/
                    /
                .  / dir
                  /
               . /
                /__
              ./   \  θ
              /     |
              -----------> _
            O              V
        transmitter        velocity
 
                  (V/c)sin(θ)
  sin(Δθ) = ------------------------- ≈ (V/c)sin(θ) + 1/2(V/c)²sin(2θ)
            sqrt(1 + 2(V/c) + (V/c)²)
 
 (non-relativistic case)
 
 Note:
 In the solar system
      V/c       ≈ 1e-4 or 1e-2 deg
      1/2(V/c)² ≈ 1e-8 or 1e-6 deg
 Only the first term is taken into account here

 

Parameters:

transmitter - provider of Transmitter PV coordinates

transmitterToTargetDir - light-time corrected direction from Transmitter to Target

frame - expression frame of the entered transmitterToTargetDir

date - computation date of the entered transmitterToTargetDir (transmitter date)

Returns:

Transmitter-Target transmission direction corrected for stellar aberration

Throws:

PatriusException - if solar system ephemerides cannot be loaded