fr.cnes.sirius.patrius.stela
Class PerigeeAltitudeDetector

java.lang.Object
  org.orekit.propagation.events.AbstractDetector
      fr.cnes.sirius.patrius.stela.PerigeeAltitudeDetector

All Implemented Interfaces:

Serializable, EventDetector

public class PerigeeAltitudeDetector
extends AbstractDetector

Finder for satellite altitude crossing events in Semi-analytical theory.

This class finds altitude events (i.e. satellite crossing a predefined altitude level above ground). The altitude computed here is the one of the perigee

The default implementation behavior is to continue propagation when ascending and to stop propagation when descending. This can be changed by overriding the eventOccurred method in a derived class.

Since:

1.3

Version:

$Id: PerigeeAltitudeDetector.java 17584 2017-05-10 13:26:39Z bignon $

Author:

Luc Maisonobe, Cedric Dental

See Also:

Propagator.addEventDetector(EventDetector), AltitudeDetector, Serialized Form

Concurrency :

conditionally thread-safe

Concurrency comment :

the OrbitNatureConverter attribute needs to be thread-safe

Nested Class Summary

Nested classes/interfaces inherited from interface org.orekit.propagation.events.EventDetector

EventDetector.Action

Field Summary

Fields inherited from class org.orekit.propagation.events.AbstractDetector

DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Fields inherited from interface org.orekit.propagation.events.EventDetector

DECREASING, INCREASING, INCREASING_DECREASING

Constructor Summary

PerigeeAltitudeDetector(double altitudeIn, double earthRadiusIn)
Build a new altitude detector.

PerigeeAltitudeDetector(double maxCheck, double altitudeIn, double earthRadiusIn)
Build a new altitude detector.

PerigeeAltitudeDetector(double maxCheck, double threshold, double altitudeIn, double earthRadiusIn)
Build a new altitude detector.

PerigeeAltitudeDetector(double maxCheck, double threshold, double altitudeIn, double earthRadiusIn, EventDetector.Action ascending, EventDetector.Action descending)
Build a new altitude detector.

PerigeeAltitudeDetector(double maxCheck, double threshold, double altitudeIn, double earthRadiusIn, EventDetector.Action ascending, EventDetector.Action descending, boolean removeAscending, boolean removeDescending)
Build a new altitude detector.

PerigeeAltitudeDetector(double maxCheck, double threshold, double altitudeIn, double earthRadiusIn, OrbitNatureConverter orbitConverterIn)
Build a new altitude detector, with osculating perigee.

PerigeeAltitudeDetector(double maxCheck, double threshold, double altitudeIn, double earthRadiusIn, OrbitNatureConverter orbitConverterIn, EventDetector.Action ascending, EventDetector.Action descending)
Build a new altitude detector, with osculating perigee.

PerigeeAltitudeDetector(double maxCheck, double threshold, double altitudeIn, double earthRadiusIn, OrbitNatureConverter orbitConverterIn, EventDetector.Action ascending, EventDetector.Action descending, boolean removeAscending, boolean removeDescending)
Build a new altitude detector, with osculating perigee.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle an altitude event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
double	getAltitude() Get the threshold altitude value.
double	getEarthRadius() Get the earth radius.
boolean	shouldBeRemoved() This method is called after EventDetector.eventOccurred(org.orekit.propagation.SpacecraftState, boolean, boolean) has been triggered.

Methods inherited from class org.orekit.propagation.events.AbstractDetector

getMaxCheckInterval, getMaxIterationCount, getSlopeSelection, getThreshold, init, resetState

Methods inherited from class java.lang.Object

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

Constructor Detail

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double altitudeIn,
                               double earthRadiusIn)

Build a new altitude detector.

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

Parameters:

altitudeIn - threshold altitude value

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double altitudeIn,
                               double earthRadiusIn)

Build a new altitude detector.

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

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

Parameters:

maxCheck - maximal checking interval (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double threshold,
                               double altitudeIn,
                               double earthRadiusIn)

Build a new altitude detector.

The maximal interval between altitude 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 when ascending and to stop propagation when descending.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double threshold,
                               double altitudeIn,
                               double earthRadiusIn,
                               EventDetector.Action ascending,
                               EventDetector.Action descending)

Build a new altitude detector.

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

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

ascending - action performed when ascending

descending - action performed when descending

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double threshold,
                               double altitudeIn,
                               double earthRadiusIn,
                               EventDetector.Action ascending,
                               EventDetector.Action descending,
                               boolean removeAscending,
                               boolean removeDescending)

Build a new altitude detector.

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

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

ascending - action performed when ascending

descending - action performed when descending

removeAscending - true if detector should be removed when ascending

removeDescending - true if detector should be removed when descending

Since:

3.1

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double threshold,
                               double altitudeIn,
                               double earthRadiusIn,
                               OrbitNatureConverter orbitConverterIn)

Build a new altitude detector, with osculating perigee.

The maximal interval between altitude 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 when ascending and to stop propagation when descending.

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

orbitConverterIn - orbit convertor to be used when computing perigee altitude

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double threshold,
                               double altitudeIn,
                               double earthRadiusIn,
                               OrbitNatureConverter orbitConverterIn,
                               EventDetector.Action ascending,
                               EventDetector.Action descending)

Build a new altitude detector, with osculating perigee.

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

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - Earth Radius (m) with respect to which altitude should be evaluated

orbitConverterIn - orbit convertor to be used when computing perigee altitude

ascending - action performed when ascending

descending - action performed when descending

PerigeeAltitudeDetector

public PerigeeAltitudeDetector(double maxCheck,
                               double threshold,
                               double altitudeIn,
                               double earthRadiusIn,
                               OrbitNatureConverter orbitConverterIn,
                               EventDetector.Action ascending,
                               EventDetector.Action descending,
                               boolean removeAscending,
                               boolean removeDescending)

Build a new altitude detector, with osculating perigee.

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

Parameters:

maxCheck - maximal checking interval (s)

threshold - convergence threshold (s)

altitudeIn - threshold altitude value (m)

earthRadiusIn - earth Radius (m) with respect to which altitude should be evaluated

orbitConverterIn - orbit convertor to be used when computing perigee altitude

ascending - action performed when ascending

descending - action performed when descending

removeAscending - true if detector should be removed when ascending

removeDescending - true if detector should be removed when descending

Since:

3.1

Method Detail

getAltitude

public double getAltitude()

Get the threshold altitude value.

Returns:

the threshold altitude value (m)

getEarthRadius

public double getEarthRadius()

Get the earth radius.

Returns:

the body shape

eventOccurred

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

Handle an altitude event and choose what to do next.

The perigee Altitude is computed using IERS92 value for Earth Equatorial Radius.

Specified by:

eventOccurred in interface EventDetector

Specified by:

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:

stop or continue

Throws:

OrekitException - if some specific error occurs

shouldBeRemoved

public boolean shouldBeRemoved()

This method is called after EventDetector.eventOccurred(org.orekit.propagation.SpacecraftState, boolean, boolean) has been triggered. It returns true if the current detector should be removed after first event detection. WARNING: this method can be called only once a event has been triggered. Before, the value is not available.

Specified by:

shouldBeRemoved in interface EventDetector

Specified by:

shouldBeRemoved in class AbstractDetector

Returns:

true if the current detector should be removed after first event detection

g

public double g(SpacecraftState s)
         throws OrekitException

Compute the value of the switching function. This function measures the difference between the perigee altitude and the threshold altitude.

Specified by:

g in interface EventDetector

Specified by:

g in class AbstractDetector

Parameters:

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

Returns:

value of the switching function

Throws:

OrekitException - if some specific error occurs