fr.cnes.sirius.patrius.events.detectors

Class ExtremaElevationDetector

java.lang.Object

fr.cnes.sirius.patrius.events.AbstractDetector

fr.cnes.sirius.patrius.events.detectors.AbstractSignalPropagationDetector

fr.cnes.sirius.patrius.events.detectors.ExtremaElevationDetector

All Implemented Interfaces:

EventDetector, Serializable

public class ExtremaElevationDetector
extends AbstractSignalPropagationDetector

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 MIN, MAX and MIN_MAX for both.

The default implementation behaviour is to stop propagation when the minimum/maximum elevation is reached. This can be changed by using provided constructors.

Since:

1.2

Version:

$Id: ExtremaElevationDetector.java 17902 2017-09-11 09:17:02Z bignon $

Author:

Thomas Trapier

See Also:

EventDetector, Serialized Form

Concurrency :

not thread-safe

Concurrency comment :

the link to the tree of frames makes this class not thread-safe

Nested Class Summary

Nested classes/interfaces inherited from class fr.cnes.sirius.patrius.events.detectors.AbstractSignalPropagationDetector

AbstractSignalPropagationDetector.DatationChoice, AbstractSignalPropagationDetector.PropagationDelayType

Nested classes/interfaces inherited from interface fr.cnes.sirius.patrius.events.EventDetector

EventDetector.Action

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX Flag for local maximum elevation detection.
static int	MIN Flag for local minimum elevation detection.
static int	MIN_MAX Flag for both local minimum and maximum elevation detection.

Fields inherited from class fr.cnes.sirius.patrius.events.AbstractDetector

actionAtEntry, actionAtExit, DEFAULT_MAXCHECK, DEFAULT_MAXITER, DEFAULT_THRESHOLD, removeAtEntry, removeAtExit, shouldBeRemovedFlag

Fields inherited from interface fr.cnes.sirius.patrius.events.EventDetector

DECREASING, INCREASING, INCREASING_DECREASING

Constructor Summary

Constructors

Constructor and Description
ExtremaElevationDetector(TopocentricFrame topoFrame, int extremumType, double maxCheck) Constructor for a min and max elevation detector.
ExtremaElevationDetector(TopocentricFrame topoFrame, int extremumType, double maxCheck, double threshold) Constructor for a min or max elevation detector.
ExtremaElevationDetector(TopocentricFrame topoFrame, int extremumType, double maxCheck, double threshold, EventDetector.Action action) Constructor for a min or max elevation detector.
ExtremaElevationDetector(TopocentricFrame topoFrame, int extremumType, double maxCheck, double threshold, EventDetector.Action action, boolean remove) Constructor for a min or max elevation detector.
ExtremaElevationDetector(TopocentricFrame topoFrame, int extremumType, double maxCheck, double threshold, EventDetector.Action action, boolean remove, VisibilityFromStationDetector.LinkType linkTypeIn) Constructor for a min or max elevation detector.

Method Summary

Modifier and Type	Method and Description
EventDetector	copy() A copy of the detector.
EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle an extrema distance event and choose what to do next.
double	g(SpacecraftState state) Compute the value of the switching function.
AbstractSignalPropagationDetector.DatationChoice	getDatationChoice() Specify if the datation choice corresponds to the emitter date or the receiver date.
PVCoordinatesProvider	getEmitter(SpacecraftState s) Getter for the signal emitter.
VisibilityFromStationDetector.LinkType	getLinkType() Returns the type of link (it can be uplink or downlink).
PVCoordinatesProvider	getReceiver(SpacecraftState s) Getter for the signal receiver.
TopocentricFrame	getTopocentricFrame()
void	init(SpacecraftState s0, AbsoluteDate t) Initialize event handler at the start of a propagation.
void	setPropagationDelayType(AbstractSignalPropagationDetector.PropagationDelayType propagationDelayType, Frame frame) Setter for the propagation delay computation type.

Methods inherited from class fr.cnes.sirius.patrius.events.detectors.AbstractSignalPropagationDetector

getEpsilonSignalPropagation, getInertialFrame, getMaxIterSignalPropagation, getPropagationDelayType, getSignalEmissionDate, getSignalEmissionDate, getSignalReceptionDate, getSignalReceptionDate, setEpsilonSignalPropagation, setMaxIterSignalPropagation

Methods inherited from class fr.cnes.sirius.patrius.events.AbstractDetector

filterEvent, getActionAtEntry, getActionAtExit, getMaxCheckInterval, getMaxIterationCount, getSlopeSelection, getThreshold, isRemoveAtEntry, isRemoveAtExit, logEventsOverTimeInterval, resetState, setMaxCheckInterval, setMaxIter, shouldBeRemoved

Methods inherited from class java.lang.Object

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

Field Detail

MIN

public static final int MIN

Flag for local minimum elevation detection.

See Also:

Constant Field Values

MAX

public static final int MAX

Flag for local maximum elevation detection.

See Also:

Constant Field Values

MIN_MAX

public static final int MIN_MAX

Flag for both local minimum and maximum elevation detection.

See Also:

Constant Field Values

Constructor Detail

ExtremaElevationDetector

public ExtremaElevationDetector(TopocentricFrame topoFrame,
                                int extremumType,
                                double maxCheck)

Constructor for a min and max elevation detector.

This constructor takes default value for convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

The maximal interval between elevation checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

topoFrame - topocentric frame in which elevation should be evaluated

extremumType - MIN for minimal elevation detection, MAX for maximal elevation detection or MIN_MAX for both shortest and farthest elevation detection

maxCheck - maximal checking interval (s)

ExtremaElevationDetector

public ExtremaElevationDetector(TopocentricFrame topoFrame,
                                int extremumType,
                                double maxCheck,
                                double threshold)

Constructor for a min or max elevation detector.

The maximal interval between elevation checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

The default implementation behavior is to stop propagation when the expected extremum is reached.

Parameters:

topoFrame - topocentric frame in which elevation should be evaluated

extremumType - MIN for minimal elevation detection, MAX for maximal elevation detection or MIN_MAX for both shortest and farthest elevation detection

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

ExtremaElevationDetector

public ExtremaElevationDetector(TopocentricFrame topoFrame,
                                int extremumType,
                                double maxCheck,
                                double threshold,
                                EventDetector.Action action)

Constructor for a min or max elevation detector.

The maximal interval between elevation checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

topoFrame - topocentric frame in which elevation should be evaluated

extremumType - MIN for minimal elevation detection, MAX for maximal elevation detection or MIN_MAX for both shortest and farthest elevation detection

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

action - action performed at extrema elevation detection

ExtremaElevationDetector

public ExtremaElevationDetector(TopocentricFrame topoFrame,
                                int extremumType,
                                double maxCheck,
                                double threshold,
                                EventDetector.Action action,
                                boolean remove)

Constructor for a min or max elevation detector.

The maximal interval between elevation checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

topoFrame - topocentric frame in which elevation should be evaluated

extremumType - MIN for minimal elevation detection, MAX for maximal elevation detection or MIN_MAX for both shortest and farthest elevation detection

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

action - action performed at extrema elevation detection

remove - true if detector should be removed at extrema elevation detection

Since:

3.1

ExtremaElevationDetector

public ExtremaElevationDetector(TopocentricFrame topoFrame,
                                int extremumType,
                                double maxCheck,
                                double threshold,
                                EventDetector.Action action,
                                boolean remove,
                                VisibilityFromStationDetector.LinkType linkTypeIn)

Constructor for a min or max elevation detector.

The maximal interval between elevation checks should be smaller than the half duration of the minimal pass to handle, otherwise some short passes could be missed.

Parameters:

topoFrame - topocentric frame in which elevation should be evaluated

extremumType - MIN for minimal elevation detection, MAX for maximal elevation detection or MIN_MAX for both shortest and farthest elevation detection

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

action - action performed at extrema elevation detection

remove - true if detector should be removed at extrema elevation detection

linkTypeIn - the type of link (it can be uplink or downlink, or null if instantaneous propagation)

Since:

4.10

Method Detail

init

public 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.

Specified by:

init in interface EventDetector

Overrides:

init in class AbstractDetector

Parameters:

s0 - initial state

t - target time for the integration

eventOccurred

public EventDetector.Action eventOccurred(SpacecraftState s,
                                          boolean increasing,
                                          boolean forward)
                                   throws PatriusException

Handle an extrema distance event and choose what to do next.

Specified by:

eventOccurred in interface EventDetector

Overrides:

eventOccurred in class AbstractDetector

Parameters:

s - the current state information : date, kinematics, attitude

increasing - if true, the value of the switching function increases when times increases around event

forward - if true, the integration variable (time) increases during integration.

Returns:

the action performed when the expected extrema elevation is reached

Throws:

PatriusException - if some specific error occurs

g

public double g(SpacecraftState state)
         throws PatriusException

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.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector

Parameters:

state - the current state information: date, kinematics, attitude for forces and events computation, mass provider, and additional states

Returns:

value of the switching function

Throws:

PatriusException - if some specific error occurs

getTopocentricFrame

public TopocentricFrame getTopocentricFrame()

Returns:

the Topocentric frame in which elevation should be evaluated.

getLinkType

public VisibilityFromStationDetector.LinkType getLinkType()

Returns the type of link (it can be uplink or downlink).

Returns:

the type of link (it can be uplink or downlink)

setPropagationDelayType

public void setPropagationDelayType(AbstractSignalPropagationDetector.PropagationDelayType propagationDelayType,
                                    Frame frame)

Setter for the propagation delay computation type. Warning: check Javadoc of detector to see if detector takes into account propagation time delay. if not, signals are always considered instantaneous. The provided frame is used to compute the signal propagation when delay is taken into account.

Overrides:

setPropagationDelayType in class AbstractSignalPropagationDetector

Parameters:

propagationDelayType - Propagation delay type used in events computation

frame - Frame to use for signal propagation with delay (may be null if propagation delay type is considered instantaneous). Warning: the usage of a pseudo inertial frame is tolerated, however it will lead to some inaccuracies due to the non-invariance of the frame with respect to time. For this reason, it is suggested to use the ICRF frame or a frame which is frozen with respect to the ICRF.

getEmitter

public PVCoordinatesProvider getEmitter(SpacecraftState s)

Getter for the signal emitter.

Specified by:

getEmitter in class AbstractSignalPropagationDetector

Parameters:

s - the spacecraft state used by the detector

Returns:

the signal emitter

getReceiver

public PVCoordinatesProvider getReceiver(SpacecraftState s)

Getter for the signal receiver.

Specified by:

getReceiver in class AbstractSignalPropagationDetector

Parameters:

s - the spacecraft state used by the detector

Returns:

the signal receiver

getDatationChoice

public AbstractSignalPropagationDetector.DatationChoice getDatationChoice()

Specify if the datation choice corresponds to the emitter date or the receiver date.

Specified by:

getDatationChoice in class AbstractSignalPropagationDetector

Returns:

the corresponding datation choice

copy

public EventDetector copy()

A copy of the detector. By default copy is deep. If not, detector javadoc will specify which attribute is not fully copied. In that case, the attribute reference is passed.

The following attributes are not deeply copied:

• topo: TopocentricFrame

Returns:

a copy of the detector.