Package org.orekit.propagation.events

Class BetaAngleDetector

java.lang.Object
org.orekit.propagation.events.AbstractDetector<BetaAngleDetector>
org.orekit.propagation.events.BetaAngleDetector
All Implemented Interfaces:
EventDetector
public class BetaAngleDetector extends AbstractDetector<BetaAngleDetector>
Finder for beta angle crossing events.

Locate events when the beta angle (the angle between the orbit plane and the celestial body) crosses a threshold. The g(SpacecraftState) function is negative when the beta angle is above the threshold and positive when the beta angle is below the threshold.

The inertial frame provided must have it's origin centered at the satellite's orbit plane. The beta angle is computed as the angle between the celestial body's position in this frame with the satellite's orbital momentum vector.

The default implementation behavior is to stop propagation at the first event date occurrence. This can be changed by calling AbstractDetector.withHandler(EventHandler) after construction.

Since:
12.1
Author:
Joe Reed
See Also:

  • Constructor Details

    • BetaAngleDetector

      @DefaultDataContext public BetaAngleDetector(double betaAngleThreshold)
      Solar beta angle constructor.

      This method uses the default data context, assigns the sun as the celestial body and uses GCRF as the inertial frame.

      Parameters:
      betaAngleThreshold - beta angle threshold (radians)

    • BetaAngleDetector

      public BetaAngleDetector(double betaAngleThreshold, PVCoordinatesProvider celestialBodyProvider, Frame inertialFrame)
      Class constructor.
      Parameters:
      betaAngleThreshold - beta angle threshold (radians)
      celestialBodyProvider - coordinate provider for the celestial provider
      inertialFrame - inertial frame in which to compute the beta angle

    • BetaAngleDetector

      protected BetaAngleDetector(EventDetectionSettings detectionSettings, EventHandler handler, double betaAngleThreshold, PVCoordinatesProvider celestialBodyProvider, Frame inertialFrame)
      Protected constructor with full parameters.

      This constructor is not public as users are expected to use the builder API with the various withXxx() methods to set up the instance in a readable manner without using a huge amount of parameters.

      Parameters:
      detectionSettings - detection settings
      handler - event handler to call at event occurrences
      betaAngleThreshold - beta angle threshold (radians)
      celestialBodyProvider - coordinate provider for the celestial provider
      inertialFrame - inertial frame in which to compute the beta angle

  • Method Details

    • getCelestialBodyProvider

      public PVCoordinatesProvider getCelestialBodyProvider()
      Coordinate provider for the celestial body.
      Returns:
      celestial body's coordinate provider

    • getInertialFrame

      public Frame getInertialFrame()
      The inertial frame in which beta angle is computed.
      Returns:
      the inertial frame

    • getBetaAngleThreshold

      public double getBetaAngleThreshold()
      The beta angle threshold (radians).
      Returns:
      the beta angle threshold (radians)

    • withCelestialProvider

      public BetaAngleDetector withCelestialProvider(PVCoordinatesProvider newProvider)
      Create a new instance with the provided coordinate provider.

      This method does not change the current instance.

      Parameters:
      newProvider - the new coordinate provider
      Returns:
      the new detector instance

    • withBetaThreshold

      public BetaAngleDetector withBetaThreshold(double newBetaAngleThreshold)
      Create a new instance with the provided beta angle threshold.

      This method does not change the current instance.

      Parameters:
      newBetaAngleThreshold - the beta angle threshold (radians)
      Returns:
      the new detector instance

    • withInertialFrame

      public BetaAngleDetector withInertialFrame(Frame newFrame)
      Create a new instance with the provided inertial frame.

      This method does not change the current instance.

      Parameters:
      newFrame - the inertial frame
      Returns:
      the new detector instance

    • g

      public double g(SpacecraftState s)
      Compute the value of the switching function. This function must be continuous (at least in its roots neighborhood), as the integrator will need to find its roots to locate the events.
      Parameters:
      s - the current state information: date, kinematics, attitude
      Returns:
      value of the switching function

    • calculateBetaAngle

      public static double calculateBetaAngle(SpacecraftState state, PVCoordinatesProvider celestialBodyProvider)
      Calculate the beta angle between the orbit plane and the celestial body.

      This method computes the beta angle using the frame from the spacecraft state.

      Parameters:
      state - spacecraft state
      celestialBodyProvider - celestial body coordinate provider
      Returns:
      the beta angle (radians)

    • calculateBetaAngle

      public static double calculateBetaAngle(SpacecraftState state, PVCoordinatesProvider celestialBodyProvider, Frame frame)
      Calculate the beta angle between the orbit plane and the celestial body.
      Parameters:
      state - spacecraft state
      celestialBodyProvider - celestial body coordinate provider
      frame - inertial frame in which beta angle will be computed
      Returns:
      the beta angle (radians)

    • create

      protected BetaAngleDetector create(EventDetectionSettings detectionSettings, EventHandler newHandler)
      Build a new instance.
      Specified by:
      create in class AbstractDetector<BetaAngleDetector>
      Parameters:
      detectionSettings - detection settings
      newHandler - event handler to call at event occurrences
      Returns:
      a new instance of the appropriate sub-type