fr.cnes.sirius.patrius.events.detectors

Class GroundMaskElevationDetector

java.lang.Object

fr.cnes.sirius.patrius.events.AbstractDetector

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

fr.cnes.sirius.patrius.events.detectors.GroundMaskElevationDetector

All Implemented Interfaces:

EventDetector, Serializable

public class GroundMaskElevationDetector
extends AbstractSignalPropagationDetector

Finder for satellite azimuth-elevation events with respect to a mask.

This class finds elevation events (i.e. satellite raising and setting) with respect to an azimuth-elevation mask.

An azimuth-elevation mask defines the physical horizon for a local point, origin of some topocentric frame.

Azimuth is defined according to getAzimuth.
Elevation is defined according to getElevation.

The azimuth elevation mask must be supplied as a twodimensional array with multiples lines of pairs of azimuth-elevation angles. First row will be filled with azimuth values, second row with elevation values, as in the following snippet:

 double[][] mask = { { FastMath.toRadians(0), FastMath.toRadians(10) },
     { FastMath.toRadians(45), FastMath.toRadians(8) },
     { FastMath.toRadians(90), FastMath.toRadians(6) },
     { FastMath.toRadians(135), FastMath.toRadians(4) },
     { FastMath.toRadians(180), FastMath.toRadians(5) },
     { FastMath.toRadians(225), FastMath.toRadians(6) },
     { FastMath.toRadians(270), FastMath.toRadians(8) },
     { FastMath.toRadians(315), FastMath.toRadians(9) } };
 

No assumption is made on azimuth values and ordering. The only restraint is that only one elevation value can be associated to identical azimuths modulo 2PI.

The default implementation behavior is to continue propagation at raising and to stop propagation at setting. This can be changed by using provided constructors.

This detector can takes into account signal propagation duration through AbstractSignalPropagationDetector.setPropagationDelayType(PropagationDelayType, Frame) (default is signal being instantaneous).

Author:

Pascal Parraud

See Also:

Propagator.addEventDetector(EventDetector), Serialized Form

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 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
GroundMaskElevationDetector(double[][] azimelev, TopocentricFrame topoIn) Build a new azimuth-elevation detector.
GroundMaskElevationDetector(double[][] azimelev, TopocentricFrame topoIn, double maxCheck) Build a new azimuth-elevation detector.
GroundMaskElevationDetector(double[][] azimelev, TopocentricFrame topoIn, double maxCheck, double threshold) Build a new azimuth-elevation detector.
GroundMaskElevationDetector(double[][] azimelev, TopocentricFrame topoIn, double maxCheck, double threshold, EventDetector.Action raising, EventDetector.Action setting) Build a new azimuth-elevation detector.
GroundMaskElevationDetector(double[][] azimelev, TopocentricFrame topoIn, double maxCheck, double threshold, EventDetector.Action raising, EventDetector.Action setting, boolean removeRaising, boolean removeSetting) Build a new azimuth-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 azimuth-elevation 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.
double	getElevation(double azimuth) Get the interpolated elevation for a given azimuth according to the mask.
PVCoordinatesProvider	getEmitter(SpacecraftState s) Getter for the signal emitter.
PVCoordinatesProvider	getReceiver(SpacecraftState s) Getter for the signal receiver.
TopocentricFrame	getTopocentricFrame() Get the topocentric frame.
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, init, 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

Constructor Detail

GroundMaskElevationDetector

public GroundMaskElevationDetector(double[][] azimelev,
                                   TopocentricFrame topoIn)

Build a new azimuth-elevation detector.

This simple constructor takes default values for maximal checking interval ( AbstractDetector.DEFAULT_MAXCHECK) and convergence threshold (AbstractDetector.DEFAULT_THRESHOLD).

Parameters:

azimelev - azimuth-elevation mask (rad)

topoIn - topocentric frame in which elevation should be evaluated

Throws:

IllegalArgumentException - if azimuth-elevation mask is not supported

GroundMaskElevationDetector

public GroundMaskElevationDetector(double[][] azimelev,
                                   TopocentricFrame topoIn,
                                   double maxCheck)

Build a new azimuth-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:

azimelev - azimuth-elevation mask (rad)

topoIn - topocentric frame in which elevation should be evaluated

maxCheck - maximal checking interval (s)

Throws:

IllegalArgumentException - if azimuth-elevation mask is not supported

GroundMaskElevationDetector

public GroundMaskElevationDetector(double[][] azimelev,
                                   TopocentricFrame topoIn,
                                   double maxCheck,
                                   double threshold)

Build a new azimuth-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 continue propagation at raising and to stop propagation at setting.

Parameters:

azimelev - azimuth-elevation mask (rad)

topoIn - topocentric frame in which elevation should be evaluated

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

Throws:

IllegalArgumentException - if azimuth-elevation mask is not supported

GroundMaskElevationDetector

public GroundMaskElevationDetector(double[][] azimelev,
                                   TopocentricFrame topoIn,
                                   double maxCheck,
                                   double threshold,
                                   EventDetector.Action raising,
                                   EventDetector.Action setting)

Build a new azimuth-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:

azimelev - azimuth-elevation mask (rad)

topoIn - topocentric frame in which elevation should be evaluated

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

raising - action performed when propagation at raising

setting - action performed when propagation at setting

Throws:

IllegalArgumentException - if azimuth-elevation mask is not supported

GroundMaskElevationDetector

public GroundMaskElevationDetector(double[][] azimelev,
                                   TopocentricFrame topoIn,
                                   double maxCheck,
                                   double threshold,
                                   EventDetector.Action raising,
                                   EventDetector.Action setting,
                                   boolean removeRaising,
                                   boolean removeSetting)

Build a new azimuth-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:

azimelev - azimuth-elevation mask (rad)

topoIn - topocentric frame in which elevation should be evaluated

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

raising - action performed when propagation at raising

setting - action performed when propagation at setting

removeRaising - if detector should be removed at raising

removeSetting - if detector should be removed at setting

Throws:

IllegalArgumentException - if azimuth-elevation mask is not supported

Method Detail

getTopocentricFrame

public TopocentricFrame getTopocentricFrame()

Get the topocentric frame.

Returns:

the topocentric frame

eventOccurred

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

Handle an azimuth-elevation 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 propagation raising or setting.

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. Compute the value of the switching function. This function measures the difference between the current elevation and the elevation for current azimuth interpolated from azimuth-elevation mask.

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

getElevation

public double getElevation(double azimuth)

Get the interpolated elevation for a given azimuth according to the mask.

Parameters:

azimuth - azimuth (rad)

Returns:

elevation angle (rad)

setPropagationDelayType

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

Description copied from class: AbstractSignalPropagationDetector

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.