org.orekit.propagation.events
Class LocalTimeAngleDetector

java.lang.Object
  org.orekit.propagation.events.AbstractDetector
      org.orekit.propagation.events.LocalTimeAngleDetector

All Implemented Interfaces:

Serializable, EventDetector

public class LocalTimeAngleDetector
extends AbstractDetector

Detects when the local time angle 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 (Local Time In Hours = 12.00h + local time angle * 12 / Π).

The default implementation is to stop propagation when the local time is reached. This can be changed by using provided constructors.

Since:

1.1

Version:

$Id: LocalTimeAngleDetector.java 17582 2017-05-10 12:58:16Z bignon $

Author:

Tiziana Sabatini

See Also:

EventDetector, Serialized Form

Concurrency :

not thread-safe

Concurrency comment :

attributes are mutable and related to propagation.

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

LocalTimeAngleDetector(double localTimeAngle)
Constructor for a LocalTimeDetector instance.

LocalTimeAngleDetector(double localTimeAngle, double maxCheck, double threshold)
Constructor for a LocalTimeDetector instance with complimentary parameters.

LocalTimeAngleDetector(double localTimeAngle, double maxCheck, double threshold, EventDetector.Action action)
Constructor for a LocalTimeDetector instance with complimentary parameters.

LocalTimeAngleDetector(double localTimeAngle, double maxCheck, double threshold, EventDetector.Action action, boolean remove)
Constructor for a LocalTimeDetector instance with complimentary parameters.

Method Summary

EventDetector.Action	eventOccurred(SpacecraftState s, boolean increasing, boolean forward) Handle a local time angle event and choose what to do next.
double	g(SpacecraftState s) Compute the value of the switching function.
double	getTime() Get local time angle to detect.
void	init(SpacecraftState s0, AbsoluteDate t) Initialize event handler at the start of a propagation.
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, resetState

Methods inherited from class java.lang.Object

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

Constructor Detail

LocalTimeAngleDetector

public LocalTimeAngleDetector(double localTimeAngle)
                       throws OrekitException

Constructor for a LocalTimeDetector instance.

Parameters:

localTimeAngle - satellite local time angle triggering the event (in the range [-Π, Π[). Angle between the projections of the Sun and the satellite in the equatorial plane (Local Time In Hours = 12.00h + localTimeAngle * 12 / Π)

Throws:

OrekitException - error when loading the ephemeris files or local time angle not in the range [-Π, Π[

LocalTimeAngleDetector

public LocalTimeAngleDetector(double localTimeAngle,
                              double maxCheck,
                              double threshold)
                       throws OrekitException

Constructor for a LocalTimeDetector instance with complimentary parameters.

The default implementation behavior is to stop propagation when the local time is reached.

Parameters:

localTimeAngle - satellite local time angle triggering the event (in the range [-Π, Π[). Angle between the projections of the Sun and the satellite in the equatorial plane (Local Time In Hours = 12.00h + localTimeAngle * 12 / Π)

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

Throws:

OrekitException - error when loading the ephemeris files or local time angle not in the range [-Π, Π[

LocalTimeAngleDetector

public LocalTimeAngleDetector(double localTimeAngle,
                              double maxCheck,
                              double threshold,
                              EventDetector.Action action)
                       throws OrekitException

Constructor for a LocalTimeDetector instance with complimentary parameters.

Parameters:

localTimeAngle - satellite local time angle triggering the event (in the range [-Π, Π[). Angle between the projections of the Sun and the satellite in the equatorial plane (Local Time In Hours = 12.00h + localTimeAngle * 12 / Π)

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at local time detection

Throws:

OrekitException - error when loading the ephemeris files or local time angle not in the range [-Π, Π[

LocalTimeAngleDetector

public LocalTimeAngleDetector(double localTimeAngle,
                              double maxCheck,
                              double threshold,
                              EventDetector.Action action,
                              boolean remove)
                       throws OrekitException

Constructor for a LocalTimeDetector instance with complimentary parameters.

Parameters:

localTimeAngle - satellite local time angle triggering the event (in the range [-Π, Π[). Angle between the projections of the Sun and the satellite in the equatorial plane (Local Time In Hours = 12.00h + localTimeAngle * 12 / Π)

maxCheck - maximum check (see AbstractDetector)

threshold - threshold (see AbstractDetector)

action - action performed at local time detection

remove - true if detector should be removed

Throws:

OrekitException - error when loading the ephemeris files or local time angle not in the range [-Π, Π[

Since:

3.1

Method Detail

eventOccurred

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

Handle a local time angle event and choose what to do next.

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 time increases around event

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

Returns:

the action performed when the expected local time is reached

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

Description copied from class: AbstractDetector

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:

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

Returns:

value of the switching function

Throws:

OrekitException - if some specific error occurs

init

public void init(SpacecraftState s0,
                 AbsoluteDate t)

Description copied from class: AbstractDetector

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

getTime

public double getTime()

Get local time angle to detect.

Returns:

the local time angle triggering the event (in the range [-&Pi, &Pi[).

Since:

1.2