Interface EventDetector

 All Known Implementing Classes:
AbstractDetector
,AdapterDetector
,AlignmentDetector
,AltitudeDetector
,AngularSeparationDetector
,AngularSeparationFromSatelliteDetector
,ApsideDetector
,BetaAngleDetector
,BooleanDetector
,CylindricalShadowEclipseDetector
,DateDetector
,EclipseDetector
,ElevationDetector
,ElevationExtremumDetector
,EventEnablingPredicateFilter
,EventShifter
,EventSlopeFilter
,ExtremumApproachDetector
,FieldOfViewDetector
,FootprintOverlapDetector
,FunctionalDetector
,GeographicZoneDetector
,GroundAtNightDetector
,GroundFieldOfViewDetector
,HaloXZPlaneCrossingDetector
,ImpulseManeuver
,InterSatDirectViewDetector
,LatitudeCrossingDetector
,LatitudeExtremumDetector
,LatitudeRangeCrossingDetector
,LongitudeCrossingDetector
,LongitudeExtremumDetector
,LongitudeRangeCrossingDetector
,MagneticFieldDetector
,NegateDetector
,NodeDetector
,ParameterDrivenDateIntervalDetector
,PositionAngleDetector
,RelativeDistanceDetector
public interface EventDetector
This interface represents spacedynamics aware events detectors.It mirrors the
ODEEventHandler
interface from Hipparchus but provides a spacedynamics interface to the methods.Events detectors are a useful solution to meet the requirements of propagators concerning discrete conditions. The state of each event detector is queried by the propagator from time to time, at least once every
max check interval
but it may be more frequent. When the sign of the underlying g switching function changes, a rootfinding algorithm is run to precisely locate the event, down to a configuredconvergence threshold
. Themax check interval
is therefore devoted to separate roots and is often much larger than theconvergence threshold
.The physical meaning of the g switching function is not really used by the event detection algorithms. Its varies from event detector to event detector. One example would be a visibility detector that could use the angular elevation of the satellite above horizon as a g switching function. In this case, the function would switch from negative to positive when the satellite raises above horizon and it would switch from positive to negative when it sets backs below horizon. Another example would be an apside detector that could use the dot product of position and velocity. In this case, the function would switch from negative to positive when the satellite crosses periapsis and it would switch from positive to negative when the satellite crosses apoapsis.
When the precise state at which the g switching function changes has been located, the corresponding event is triggered, by calling the
eventOccurred
method from the associatedhandler
. The method can do whatever it needs with the event (logging it, performing some processing, ignore it ...). The return value of the method will be used by the propagator to stop or resume propagation, possibly changing the state vector. Author:
 Luc Maisonobe, Véronique PommierMaurussane


Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description double
g(SpacecraftState s)
Compute the value of the switching function.EventHandler
getHandler()
Get the handler.AdaptableInterval
getMaxCheckInterval()
Get maximal time interval between switching function checks.int
getMaxIterationCount()
Get maximal number of iterations in the event time search.double
getThreshold()
Get the convergence threshold in the event time search.default void
init(SpacecraftState s0, AbsoluteDate t)
Initialize event handler at the start of a propagation.



Method Detail

init
default void init(SpacecraftState s0, AbsoluteDate t)
Initialize event handler at the start of a propagation.This method is called once at the start of the propagation. It may be used by the event handler to initialize some internal data if needed.
The default implementation does nothing
 Parameters:
s0
 initial statet
 target time for the integration

g
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

getThreshold
double getThreshold()
Get the convergence threshold in the event time search. Returns:
 convergence threshold (s)

getMaxCheckInterval
AdaptableInterval getMaxCheckInterval()
Get maximal time interval between switching function checks. Returns:
 maximal time interval (s) between switching function checks

getMaxIterationCount
int getMaxIterationCount()
Get maximal number of iterations in the event time search. Returns:
 maximal number of iterations in the event time search

getHandler
EventHandler getHandler()
Get the handler. Returns:
 event handler to call at event occurrences
 Since:
 12.0

