Package org.orekit.propagation.events

This package provides interfaces and classes dealing with events occurring during propagation.

See:
Description

Interface Summary

EventDetector	This interface represents space-dynamics aware events detectors with support for additional states.
LocalRadiusProvider	Interface to represent radius providers.

Class Summary

AbstractDetector	Common parts shared by several events finders.
AdaptedEventDetector	Adapt an EventDetector to commons-math EventHandler interface.
AlignmentDetector	Finder for satellite/body alignment events.
AltitudeDetector	Finder for satellite altitude crossing events.
AnomalyDetector	Detects when the anomaly of the spacecraft reaches a predetermined value, θ. Anomaly is not defined for all kinds of orbits: this detector will detect anomaly events only if the corresponding orbit is not a circular orbit, otherwise it may trigger events randomly.
AOLDetector	Detects when the Argument of Latitude of the spacecraft reaches a predetermined value, θ.
ApparentElevationDetector	Finder for satellite apparent elevation events.
ApsideDetector	Finder for apside crossing events.
BetaAngleDetector	Detects when the beta angle of the spacecraft reaches a predetermined value. The beta angle is the angle between the orbit plane and the vector from the central body to the sun.
CircularFieldOfViewDetector	Finder for target entry/exit events with respect to a satellite sensor field of view.
ConstantRadiusProvider	Implementation for constant radius provider.
DateDetector	Finder for date events.
DihedralFieldOfViewDetector	Finder for body entering/exiting dihedral fov events.
DistanceDetector	Detects when the distance from the spacecraft to a given body reaches a predetermined value.
EclipseDetector	Finder for satellite eclipse related events.
ElevationDetector	Finder for satellite raising/setting events.
EventShifter	Wrapper shifting events occurrences times.
EventsLogger	This class logs events detectors events during propagation.
EventsLogger.LoggedEvent	Class for logged events entries.
EventState	This class handles the state for one event detector during integration steps.
ExtremaDistanceDetector	Detects when the distance from the spacecraft to a given body reaches either a local minimum or a local maximum.
ExtremaElevationDetector	Detects the time when the spacecraft reaches the elevation extrema in a given topocentric frame. The local minimum or maximum is chosen through a constructor parameter, with values ExtremaElevationDetector.MIN, ExtremaElevationDetector.MAX and ExtremaElevationDetector.MIN_MAX for both.
ExtremaLatitudeDetector	Detects when the spacecraft reaches the maximal or minimal local latitude.
ExtremaLongitudeDetector	Detects when the spacecraft reaches the maximal or minimal local longitude.
ExtremaThreeBodiesAngleDetector	Detects the maximal or minimal angle between three bodies is reached, the spacecraft eventually being one of the bodies.
GroundMaskElevationDetector	Finder for satellite azimuth-elevation events with respect to a mask.
LatitudeDetector	Detects when the spacecraft reaches a given local latitude.
LocalTimeDetector	Detects when the local time of a spacecraft is equal to a predetermined value. The local time is represented by the angle between the projections of the Sun and the satellite in the equatorial plane; therefore this angle is equal to zero when the local time is 12.00h and Π when the local time is 0.00h.
LongitudeDetector	Detects when the spacecraft reaches a given local longitude.
NadirSolarIncidenceDetector	Spacecraft's nadir point solar incidence detector.
NodeDetector	Finder for node crossing events.
NthOccurrenceDetector	This event detector detects the nth occurrence of an underlying event detector.
NullMassDetector	This class creates an event detector that detects when the global mass of the satellite becomes null.
NullMassPartDetector	This class creates an event detector that detects when the mass of the element becomes null.
SolarTimeDetector	Detects when the solar time of a spacecraft is equal to a predetermined value. The solar time is represented by the angle between the projections of the Sun in the osculator orbital plane and the satellite position; therefore this angle is equal to zero when the solar time is 12.00h and Π when the solar time is 0.00h.
ThreeBodiesAngleDetector	Detects when the angle between three bodies is equal to a predetermined value.
VariableRadiusProvider	Implementation for variable radius providers.

Enum Summary

EventDetector.Action	Enumerate for actions to be performed when an event occurs.
ExtremaThreeBodiesAngleDetector.BodyOrder	Bodies order type.
ThreeBodiesAngleDetector.BodyOrder	Bodies order type.

Package org.orekit.propagation.events Description

This package provides interfaces and classes dealing with events occurring during propagation. It is used when EventDetector instances are registered to any Propagator. When the event associated with the detector occurs, the propagator interrupts the propagation and calls the eventOccurred method of the event detector, which can do whatever the user want and either stop or resume propagation, optionally resetting the state.

If the registered events detectors are configured to stop propagation when triggered, the propagator can be run with an arbitrary large target date, relying on the events occurrence to stop propagation exactly at the right time.

The package provides some predefined events:

• AlignmentDetector detects satellite/body alignment (and by default stop when reaching alignment)
• AltitudeDetector detects altitude crossing (and by default stop at descending)
• ApparentElevationDetector detects apparent satellite raising/setting (and by default stop at setting)
• ApsideDetector detects apside crossing (and by default stop at perigee)
• GroundMaskElevationDetector detects satellite raising/setting according to an elevation mask (and by default stop at setting)
• CircularFieldOfViewDetector detects target entry/exit a satellite sensor field of view with a circular boundary (and by default continue on entry and stop on exit)
• DateDetector detects occurrence of a predefine instant (and by default stop there)
• DihedralFieldOfViewDetector detects target entry/exit a satellite sensor field of view with a dihedral boundary (and by default continue on entry and stop on exit)
• EclipseDetector detects satellite entering/exiting an eclipse (and by default stop on exit)
• ElevationDetector detects satellite raising/setting (and by default stop at setting)
• NodeDetector detects node crossing (and by default stop at ascending node)

The low level interfaces and classes are heavily based on similar classes from the ode.events package from the commons math library. The changes are mainly adaptations of the signatures to space dynamics.

• the type of dependent variable t has been changed from double to AbsoluteDate
• the type of state vector y has been changed from double[] to SpacecraftState

Author:

Luc Maisonobe, Pascal Parraud