Class TimeSpanDragForce
- java.lang.Object
-
- org.orekit.forces.drag.AbstractDragForceModel
-
- org.orekit.forces.drag.TimeSpanDragForce
-
- All Implemented Interfaces:
ForceModel
,EventDetectorsProvider
,ParameterDriversProvider
@Deprecated public class TimeSpanDragForce extends AbstractDragForceModel
Deprecated.as of 12.1Time span atmospheric drag force model.This class is closely related to
DragForce
class.
The difference is that it has aTimeSpanMap
ofDragSensitive
objects as attribute instead of a singleDragSensitive
object.
The idea behind this model is to allow the user to design a drag force model that can see its physical parameters (drag coefficient and lift ratio) change with time, at dates chosen by the user.
This is a behavior that can be sought in operational orbit determination.
Indeed the solar activity has a strong influence on the local atmospheric density, and thus on the drag force effect.
Solar activity is a physical phenomenon that is difficult to model and predict.
The errors induced by this incomplete modeling can be estimated through the drag coefficients.
Being able to define and estimate drag coefficients depending on user-chosen dates in a piecewise fashion allows for a better modeling of solar activity uncertainties.A typical operational use case is to have a daily solar activity with three-hourly magnetic indexes provided by an international organization (NOAA for example).
Usage:
Given this input, a user can define a piecewise drag force model with daily or three-hourly drag coefficients.
Each timed coefficient will absorb a part of the uncertainties in the solar activity and will allow for a more accurate orbit determination- Construction: constructor takes an atmospheric model and a DragSensitive model.
This last model will be your initial DragSensitive model and it will be initially valid for the whole time line.
The real validity of this first entry will be truncated as other DragSensitive models are added. - Time spans: DragSensitive models are added using methods
addDragSensitiveValidAfter(DragSensitive, AbsoluteDate)
oraddDragSensitiveValidBefore(DragSensitive, AbsoluteDate)
.
Recommendations are the same than the ones inTimeSpanMap
, meaning:- As an entry is added, it truncates the validity of the neighboring entries already present in the map;
- The transition dates should be entered only once. Repeating a transition date will lead to unexpected result and is not supported;
- It is advised to order your DragSensitive models chronologically when adding them to avoid any confusion.
- Naming the parameter drivers: It is strongly advised to give a custom name to the
ParameterDriver
(s) of each DragSensitive model that is added to the object. This will allow you keeping track of the evolution of your models.
Different names are mandatory to differentiate the different drivers.
If you do not specify a name, a default name will be chosen. Example for the drag coefficient:- Initial DragSensitive model: the driver's default name is "
DragSensitive.DRAG_COEFFICIENT
"; - Using
addDragSensitiveValidAfter(DragSensitive, AbsoluteDate)
: the driver's default name is "DragSensitive.DRAG_COEFFICIENT
+DATE_AFTER
+ date.toString()" - Using
addDragSensitiveValidBefore(DragSensitive, AbsoluteDate)
: the driver's default name is "DragSensitive.DRAG_COEFFICIENT
+DATE_BEFORE
+ date.toString()"
- Initial DragSensitive model: the driver's default name is "
- Given:
atmosphere
: anatmospheric model
;isotropicDrag0, 1 and 2
: threeIsotropicDrag
models;date
: anAbsoluteDate
.
- Name the drivers:
isotropicDrag0.getDragParametersDrivers()[0].setName = "Cd0";
isotropicDrag1.getDragParametersDrivers()[0].setName = "Cd1";
isotropicDrag2.getDragParametersDrivers()[0].setName = "Cd2";
- Initialize the model:
TimeSpanDragForce force = new TimeSpanDragForce(atmosphere, isotropicDrag0);
- Set the second and third model one Julian day apart each:
force.addDragSensitiveValidAfter(isotropicDrag1, date.shiftedBy(Constants.JULIAN_DAY));
force.addDragSensitiveValidAfter(isotropicDrag2, date.shiftedBy(2 * Constants.JULIAN_DAY));
- With this, your model will have the following properties:
- t in ]-∞, date + 1 day [ / Cd = Cd0
- t in [date + 1 day, date + 2days [ / Cd = Cd1
- t in [date + 2 days, +∞ [ / Cd = Cd2
Warning:
The TimeSpanDragForce model is versatile and you could end up with non-physical modeling.
For example you could add 2IsotropicDrag
models with different areas, or oneIsotropicDrag
model and then oneBoxAndSolarArraySpacecraft
model.
It is up to you to ensure that your models are consistent with each other, Orekit will not perform any check for that.- Since:
- 10.2
- Author:
- Maxime Journot
-
-
Field Summary
Fields Modifier and Type Field Description static String
DATE_AFTER
Deprecated.Prefix for dates after in the parameter drivers' name.static String
DATE_BEFORE
Deprecated.Prefix for dates before in the parameter drivers' name.-
Fields inherited from interface org.orekit.propagation.events.EventDetectorsProvider
DATATION_ACCURACY
-
-
Constructor Summary
Constructors Constructor Description TimeSpanDragForce(Atmosphere atmosphere, DragSensitive spacecraft)
Deprecated.Constructor with default UTC time scale for the default names of the drag parameter drivers.TimeSpanDragForce(Atmosphere atmosphere, DragSensitive spacecraft, TimeScale timeScale)
Deprecated.Constructor.
-
Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description <T extends CalculusFieldElement<T>>
FieldVector3D<T>acceleration(FieldSpacecraftState<T> s, T[] parameters)
Deprecated.Compute acceleration.Vector3D
acceleration(SpacecraftState s, double[] parameters)
Deprecated.Compute acceleration.void
addDragSensitiveValidAfter(DragSensitive dragSensitive, AbsoluteDate earliestValidityDate)
Deprecated.Add a DragSensitive entry valid after a limit date.
UsingaddDragSensitiveValidAfter(entry, t)
will makeentry
valid in [t, +∞[ (note the closed bracket).void
addDragSensitiveValidBefore(DragSensitive dragSensitive, AbsoluteDate latestValidityDate)
Deprecated.Add a DragSensitive entry valid before a limit date.
UsingaddDragSensitiveValidBefore(entry, t)
will makeentry
valid in ]-∞, t[ (note the open bracket).TimeSpanMap<DragSensitive>
extractDragSensitiveRange(AbsoluteDate start, AbsoluteDate end)
Deprecated.Extract a range of theDragSensitive
map.double[]
extractParameters(double[] parameters, AbsoluteDate date)
Deprecated.Extract the proper parameter drivers' values from the array in input of theacceleration
method.<T extends CalculusFieldElement<T>>
T[]extractParameters(T[] parameters, FieldAbsoluteDate<T> date)
Deprecated.Extract the proper parameter drivers' values from the array in input of theacceleration
method.DragSensitive
getDragSensitive(AbsoluteDate date)
Deprecated.Get theDragSensitive
model valid at a date.TimeSpanMap.Span<DragSensitive>
getDragSensitiveSpan(AbsoluteDate date)
Deprecated.Get theDragSensitive
TimeSpanMap.Span
containing a specified date.Stream<EventDetector>
getEventDetectors()
Deprecated.Get the discrete events related to the model.<T extends CalculusFieldElement<T>>
Stream<FieldEventDetector<T>>getFieldEventDetectors(Field<T> field)
Deprecated.Get the discrete events related to the model.TimeSpanMap.Span<DragSensitive>
getFirstSpan()
Deprecated.Get the firsttime span
of the drag sensitive time span map.List<ParameterDriver>
getParametersDrivers()
Deprecated.Get the drivers for parameters.-
Methods inherited from class org.orekit.forces.drag.AbstractDragForceModel
dependsOnPositionOnly, getAtmosphere, getDSDensityWrtState, getDSDensityWrtStateUsingFiniteDifferences, getFieldDensity, getGradientDensityWrtState, getGradientDensityWrtStateUsingFiniteDifferences, isDSStateDerivative, isGradientStateDerivative, isVariable, isVariable
-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
-
Methods inherited from interface org.orekit.propagation.events.EventDetectorsProvider
getEventDetectors, getFieldEventDetectors
-
Methods inherited from interface org.orekit.forces.ForceModel
addContribution, addContribution, dependsOnAttitudeRate, init, init
-
Methods inherited from interface org.orekit.utils.ParameterDriversProvider
getNbParametersDriversValue, getParameterDriver, getParameters, getParameters, getParameters, getParameters, getParametersAllValues, getParametersAllValues, isSupported
-
-
-
-
Field Detail
-
DATE_BEFORE
public static final String DATE_BEFORE
Deprecated.Prefix for dates before in the parameter drivers' name.- See Also:
- Constant Field Values
-
DATE_AFTER
public static final String DATE_AFTER
Deprecated.Prefix for dates after in the parameter drivers' name.- See Also:
- Constant Field Values
-
-
Constructor Detail
-
TimeSpanDragForce
@DefaultDataContext public TimeSpanDragForce(Atmosphere atmosphere, DragSensitive spacecraft)
Deprecated.Constructor with default UTC time scale for the default names of the drag parameter drivers.- Parameters:
atmosphere
- atmospheric modelspacecraft
- Time scale used for the default names of the drag parameter drivers
-
TimeSpanDragForce
public TimeSpanDragForce(Atmosphere atmosphere, DragSensitive spacecraft, TimeScale timeScale)
Deprecated.Constructor.- Parameters:
atmosphere
- atmospheric modelspacecraft
- the initial object physical and geometric informationtimeScale
- Time scale used for the default names of the drag parameter drivers
-
-
Method Detail
-
addDragSensitiveValidBefore
public void addDragSensitiveValidBefore(DragSensitive dragSensitive, AbsoluteDate latestValidityDate)
Deprecated.Add a DragSensitive entry valid before a limit date.
UsingaddDragSensitiveValidBefore(entry, t)
will makeentry
valid in ]-∞, t[ (note the open bracket).- Parameters:
dragSensitive
- DragSensitive entrylatestValidityDate
- date before which the entry is valid (must be different from all dates already used for transitions)
-
addDragSensitiveValidAfter
public void addDragSensitiveValidAfter(DragSensitive dragSensitive, AbsoluteDate earliestValidityDate)
Deprecated.Add a DragSensitive entry valid after a limit date.
UsingaddDragSensitiveValidAfter(entry, t)
will makeentry
valid in [t, +∞[ (note the closed bracket).- Parameters:
dragSensitive
- DragSensitive entryearliestValidityDate
- date after which the entry is valid (must be different from all dates already used for transitions)
-
getDragSensitive
public DragSensitive getDragSensitive(AbsoluteDate date)
Deprecated.Get theDragSensitive
model valid at a date.- Parameters:
date
- the date of validity- Returns:
- the DragSensitive model valid at date
-
getDragSensitiveSpan
public TimeSpanMap.Span<DragSensitive> getDragSensitiveSpan(AbsoluteDate date)
Deprecated.Get theDragSensitive
TimeSpanMap.Span
containing a specified date.- Parameters:
date
- date belonging to the desired time span- Returns:
- the DragSensitive time span containing the specified date
-
extractDragSensitiveRange
public TimeSpanMap<DragSensitive> extractDragSensitiveRange(AbsoluteDate start, AbsoluteDate end)
Deprecated.Extract a range of theDragSensitive
map.The object returned will be a new independent instance that will contain only the transitions that lie in the specified range.
See theTimeSpanMap.extractRange method
for more.- Parameters:
start
- earliest date at which a transition is included in the range (may be set toAbsoluteDate.PAST_INFINITY
to keep all early transitions)end
- latest date at which a transition is included in the r (may be set toAbsoluteDate.FUTURE_INFINITY
to keep all late transitions)- Returns:
- a new TimeSpanMap instance of DragSensitive with all transitions restricted to the specified range
-
getFirstSpan
public TimeSpanMap.Span<DragSensitive> getFirstSpan()
Deprecated.Get the firsttime span
of the drag sensitive time span map.- Returns:
- the first
time span
of the drag sensitive time span map - Since:
- 11.1
-
acceleration
public Vector3D acceleration(SpacecraftState s, double[] parameters)
Deprecated.Compute acceleration.- Parameters:
s
- current state information: date, kinematics, attitudeparameters
- values of the force model parameters at state date, only 1 value for each parameterDriver- Returns:
- acceleration in same frame as state
-
acceleration
public <T extends CalculusFieldElement<T>> FieldVector3D<T> acceleration(FieldSpacecraftState<T> s, T[] parameters)
Deprecated.Compute acceleration.- Type Parameters:
T
- type of the elements- Parameters:
s
- current state information: date, kinematics, attitudeparameters
- values of the force model parameters at state date, only 1 value for each parameterDriver- Returns:
- acceleration in same frame as state
-
getEventDetectors
public Stream<EventDetector> getEventDetectors()
Deprecated.Get the discrete events related to the model.This method is not intended to be called several time, only once by a propagator, as it has the side effect of rebuilding the events detectors when called.
A date detector is used to cleanly stop the propagator and reset the state derivatives at transition dates.
- Returns:
- stream of event detectors
-
getFieldEventDetectors
public <T extends CalculusFieldElement<T>> Stream<FieldEventDetector<T>> getFieldEventDetectors(Field<T> field)
Deprecated.Get the discrete events related to the model.This method is not intended to be called several time, only once by a propagator, as it has the side effect of rebuilding the events detectors when called.
A date detector is used to cleanly stop the propagator and reset the state derivatives at transition dates.
- Type Parameters:
T
- extends CalculusFieldElement<T>- Parameters:
field
- field to which the state belongs- Returns:
- stream of event detectors
-
getParametersDrivers
public List<ParameterDriver> getParametersDrivers()
Deprecated.Get the drivers for parameters.All the parameter drivers of all DragSensitive models are returned in an array. Models are ordered chronologically.
- Returns:
- drivers for parameters
-
extractParameters
public double[] extractParameters(double[] parameters, AbsoluteDate date)
Deprecated.Extract the proper parameter drivers' values from the array in input of theacceleration
method. Parameters are filtered given an input date.- Parameters:
parameters
- the input parameters arraydate
- the date- Returns:
- the parameters given the date
-
extractParameters
public <T extends CalculusFieldElement<T>> T[] extractParameters(T[] parameters, FieldAbsoluteDate<T> date)
Deprecated.Extract the proper parameter drivers' values from the array in input of theacceleration
method. Parameters are filtered given an input date.- Type Parameters:
T
- extends CalculusFieldElement- Parameters:
parameters
- the input parameters arraydate
- the date- Returns:
- the parameters given the date
-
-