FieldTLEPropagator (ORbit Extrapolation KIT 11.1 API)

java.lang.Object
- org.orekit.propagation.FieldAbstractPropagator<T>
- - org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator<T>
  - - org.orekit.propagation.analytical.tle.FieldTLEPropagator<T>

All Implemented Interfaces:

FieldPropagator<T>, FieldPVCoordinatesProvider<T>

Direct Known Subclasses:

FieldDeepSDP4, FieldSGP4
```
public abstract class FieldTLEPropagator<T extends CalculusFieldElement<T>>
extends FieldAbstractAnalyticalPropagator<T>
```
This class provides elements to propagate TLE's.
The models used are SGP4 and SDP4, initially proposed by NORAD as the unique convenient propagator for TLE's. Inputs and outputs of this propagator are only suited for NORAD two lines elements sets, since it uses estimations and mean values appropriate for TLE's only.

Deep- or near- space propagator is selected internally according to NORAD recommendations so that the user has not to worry about the used computation methods. One instance is created for each TLE (this instance can only be get using selectExtrapolator(FieldTLE, CalculusFieldElement[]) method, and can compute position and velocity coordinates at any time. Maximum accuracy is guaranteed in a 24h range period before and after the provided TLE epoch (of course this accuracy is not really measurable nor predictable: according to CelesTrak, the precision is close to one kilometer and error won't probably rise above 2 km).

This implementation is largely inspired from the paper and source code Revisiting Spacetrack Report #3 and is fully compliant with its results and tests cases.

Since:

11.0

Author:

Felix R. Hoots, Ronald L. Roehrich, December 1980 (original fortran), David A. Vallado, Paul Crawford, Richard Hujsak, T.S. Kelso (C++ translation and improvements), Fabien Maussion (java translation), Thomas Paulet (field translation)

See Also:

FieldTLE

Field Summary

Fields
Modifier and Type	Field and Description
`protected T`	`a` final semi major axis.
`protected T`	`a0dp` original recovered semi major axis.
`protected T`	`beta0` sqrt (1 - e2).
`protected T`	`beta02` 1 - e2.
`protected T`	`c1` C1 from SPTRCK #3.
`protected T`	`c2` C2 from SPTRCK #3.
`protected T`	`c4` C4 from SPTRCK #3.
`protected T`	`coef` coef for SGP C3 computation.
`protected T`	`coef1` coef for SGP C5 computation.
`protected T`	`cosi0` cosinus original inclination.
`protected T`	`e` final eccentricity.
`protected T`	`e0sq` original eccentricity squared.
`protected T`	`eeta` original eccentricity * eta.
`protected T`	`eta` eta from SPTRCK #3.
`protected T`	`etasq` eta squared.
`protected T`	`i` final inclination.
`protected T`	`omega` final perigee argument.
`protected T`	`omgdot` common parameter for perigee argument (omega) computation.
`protected T`	`perige` perigee, expressed in KM and ALTITUDE.
`protected T`	`s4` s* new value for the contant s.
`protected T`	`sini0` sinus original inclination.
`protected T`	`t2cof` 3/2 * C1.
`protected T`	`theta2` cos io squared.
`protected FieldTLE<T>`	`tle` Initial state.
`protected T`	`tsi` tsi from SPTRCK #3.
`protected TimeScale`	`utc` UTC time scale.
`protected T`	`xl` L from SPTRCK #3.
`protected T`	`xmdot` common parameter for mean anomaly (M) computation.
`protected T`	`xn0dp` original recovered mean motion.
`protected T`	`xnodcf` common parameter for raan (OMEGA) computation.
`protected T`	`xnode` final RAAN.
`protected T`	`xnodot` common parameter for raan (OMEGA) computation.

Fields inherited from interface org.orekit.propagation.FieldPropagator
DEFAULT_MASS

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`FieldTLEPropagator(FieldTLE<T> initialTLE, AttitudeProvider attitudeProvider, T mass, Frame teme, T[] parameters)` Protected constructor for derived classes.
`protected`	`FieldTLEPropagator(FieldTLE<T> initialTLE, AttitudeProvider attitudeProvider, T mass, T[] parameters)` Protected constructor for derived classes.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`Frame`	`getFrame()` Get the frame in which the orbit is propagated.
`protected T`	`getMass(FieldAbsoluteDate<T> date)` Get the mass.
`static double`	`getMU()` Get the Earth gravity coefficient used for TLE propagation.
`List<ParameterDriver>`	`getParametersDrivers()` Get the parameters driver for propagation model.
`FieldPVCoordinates<T>`	`getPVCoordinates(FieldAbsoluteDate<T> date, T[] parameters)` Get the extrapolated position and velocity from an initial TLE.
`FieldTLE<T>`	`getTLE()` Get the underlying TLE.
`FieldOrbit<T>`	`propagateOrbit(FieldAbsoluteDate<T> date, T[] parameters)` Extrapolate an orbit up to a specific target date.
`void`	`resetInitialState(FieldSpacecraftState<T> state)` Reset the propagator initial state.
`protected void`	`resetIntermediateState(FieldSpacecraftState<T> state, boolean forward)` Reset an intermediate state.
`static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T>`	`selectExtrapolator(FieldTLE<T> tle, AttitudeProvider attitudeProvider, T mass, Frame teme, T[] parameters)` Selects the extrapolator to use with the selected TLE.
`static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T>`	`selectExtrapolator(FieldTLE<T> tle, AttitudeProvider attitudeProvider, T mass, T[] parameters)` Selects the extrapolator to use with the selected TLE.
`static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T>`	`selectExtrapolator(FieldTLE<T> tle, Frames frames, T[] parameters)` Selects the extrapolator to use with the selected TLE.
`static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T>`	`selectExtrapolator(FieldTLE<T> tle, T[] parameters)` Selects the extrapolator to use with the selected TLE.
`protected abstract void`	`sxpInitialize(T[] parameters)` Initialization proper to each propagator (SGP or SDP).
`protected abstract void`	`sxpPropagate(T t, T[] parameters)` Propagation proper to each propagator (SGP or SDP).

Methods inherited from class org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator
acceptStep, addEventDetector, basicPropagate, clearEventsDetectors, getEphemerisGenerator, getEventsDetectors, getParameters, getPvProvider, propagate

Methods inherited from class org.orekit.propagation.FieldAbstractPropagator
addAdditionalStateProvider, getAdditionalStateProviders, getAttitudeProvider, getField, getInitialState, getManagedAdditionalStates, getMultiplexer, getPVCoordinates, getStartDate, initializePropagation, isAdditionalStateManaged, propagate, setAttitudeProvider, setStartDate, stateChanged, updateAdditionalStates, updateUnmanagedStates

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.FieldPropagator
clearStepHandlers, setStepHandler, setStepHandler

- Field Detail
  - tle
```
protected FieldTLE<T extends CalculusFieldElement<T>> tle
```
    Initial state.
  - utc
```
protected final TimeScale utc
```
    UTC time scale.
  - xnode
```
protected T extends CalculusFieldElement<T> xnode
```
    final RAAN.
  - a
```
protected T extends CalculusFieldElement<T> a
```
    final semi major axis.
  - e
```
protected T extends CalculusFieldElement<T> e
```
    final eccentricity.
  - i
```
protected T extends CalculusFieldElement<T> i
```
    final inclination.
  - omega
```
protected T extends CalculusFieldElement<T> omega
```
    final perigee argument.
  - xl
```
protected T extends CalculusFieldElement<T> xl
```
    L from SPTRCK #3.
  - a0dp
```
protected T extends CalculusFieldElement<T> a0dp
```
    original recovered semi major axis.
  - xn0dp
```
protected T extends CalculusFieldElement<T> xn0dp
```
    original recovered mean motion.
  - cosi0
```
protected T extends CalculusFieldElement<T> cosi0
```
    cosinus original inclination.
  - theta2
```
protected T extends CalculusFieldElement<T> theta2
```
    cos io squared.
  - sini0
```
protected T extends CalculusFieldElement<T> sini0
```
    sinus original inclination.
  - xmdot
```
protected T extends CalculusFieldElement<T> xmdot
```
    common parameter for mean anomaly (M) computation.
  - omgdot
```
protected T extends CalculusFieldElement<T> omgdot
```
    common parameter for perigee argument (omega) computation.
  - xnodot
```
protected T extends CalculusFieldElement<T> xnodot
```
    common parameter for raan (OMEGA) computation.
  - e0sq
```
protected T extends CalculusFieldElement<T> e0sq
```
    original eccentricity squared.
  - beta02
```
protected T extends CalculusFieldElement<T> beta02
```
    1 - e2.
  - beta0
```
protected T extends CalculusFieldElement<T> beta0
```
    sqrt (1 - e2).
  - perige
```
protected T extends CalculusFieldElement<T> perige
```
    perigee, expressed in KM and ALTITUDE.
  - etasq
```
protected T extends CalculusFieldElement<T> etasq
```
    eta squared.
  - eeta
```
protected T extends CalculusFieldElement<T> eeta
```
    original eccentricity * eta.
  - s4
```
protected T extends CalculusFieldElement<T> s4
```
    s* new value for the contant s.
  - tsi
```
protected T extends CalculusFieldElement<T> tsi
```
    tsi from SPTRCK #3.
  - eta
```
protected T extends CalculusFieldElement<T> eta
```
    eta from SPTRCK #3.
  - coef
```
protected T extends CalculusFieldElement<T> coef
```
    coef for SGP C3 computation.
  - coef1
```
protected T extends CalculusFieldElement<T> coef1
```
    coef for SGP C5 computation.
  - c1
```
protected T extends CalculusFieldElement<T> c1
```
    C1 from SPTRCK #3.
  - c2
```
protected T extends CalculusFieldElement<T> c2
```
    C2 from SPTRCK #3.
  - c4
```
protected T extends CalculusFieldElement<T> c4
```
    C4 from SPTRCK #3.
  - xnodcf
```
protected T extends CalculusFieldElement<T> xnodcf
```
    common parameter for raan (OMEGA) computation.
  - t2cof
```
protected T extends CalculusFieldElement<T> t2cof
```
    3/2 * C1.
- Constructor Detail
  - FieldTLEPropagator
```
@DefaultDataContext
protected FieldTLEPropagator(FieldTLE<T> initialTLE,
                                                 AttitudeProvider attitudeProvider,
                                                 T mass,
                                                 T[] parameters)
```
    Protected constructor for derived classes.
    This constructor uses the default data context.
    
    Parameters:
    
    initialTLE - the unique TLE to propagate
    
    attitudeProvider - provider for attitude computation
    
    mass - spacecraft mass (kg)
    
    parameters - SGP4 and SDP4 model parameters
    
    See Also:
    
    FieldTLEPropagator(FieldTLE, AttitudeProvider, CalculusFieldElement, Frame, CalculusFieldElement[])
  - FieldTLEPropagator
```
protected FieldTLEPropagator(FieldTLE<T> initialTLE,
                             AttitudeProvider attitudeProvider,
                             T mass,
                             Frame teme,
                             T[] parameters)
```
    Protected constructor for derived classes.
    
    Parameters:
    
    initialTLE - the unique TLE to propagate
    
    attitudeProvider - provider for attitude computation
    
    mass - spacecraft mass (kg)
    
    teme - the TEME frame to use for propagation.
    
    parameters - SGP4 and SDP4 model parameters
- Method Detail
  - selectExtrapolator
```
@DefaultDataContext
public static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T> selectExtrapolator(FieldTLE<T> tle,
                                                                                                               T[] parameters)
```
    Selects the extrapolator to use with the selected TLE.
    This method uses the default data context.
    
    Type Parameters:
    
    T - elements type
    
    Parameters:
    
    tle - the TLE to propagate.
    
    parameters - SGP4 and SDP4 model parameters
    
    Returns:
    
    the correct propagator.
    
    See Also:
    
    selectExtrapolator(FieldTLE, Frames, CalculusFieldElement[])
  - selectExtrapolator
```
public static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T> selectExtrapolator(FieldTLE<T> tle,
                                                                                           Frames frames,
                                                                                           T[] parameters)
```
    Selects the extrapolator to use with the selected TLE.
    This method uses the default data context.
    
    Type Parameters:
    
    T - elements type
    
    Parameters:
    
    tle - the TLE to propagate.
    
    frames - set of Frames to use in the propagator.
    
    parameters - SGP4 and SDP4 model parameters
    
    Returns:
    
    the correct propagator.
  - selectExtrapolator
```
@DefaultDataContext
public static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T> selectExtrapolator(FieldTLE<T> tle,
                                                                                                               AttitudeProvider attitudeProvider,
                                                                                                               T mass,
                                                                                                               T[] parameters)
```
    Selects the extrapolator to use with the selected TLE.
    This method uses the default data context.
    
    Type Parameters:
    
    T - elements type
    
    Parameters:
    
    tle - the TLE to propagate.
    
    attitudeProvider - provider for attitude computation
    
    mass - spacecraft mass (kg)
    
    parameters - SGP4 and SDP4 model parameters
    
    Returns:
    
    the correct propagator.
    
    See Also:
    
    selectExtrapolator(FieldTLE, AttitudeProvider, CalculusFieldElement, Frame, CalculusFieldElement[])
  - selectExtrapolator
```
public static <T extends CalculusFieldElement<T>> FieldTLEPropagator<T> selectExtrapolator(FieldTLE<T> tle,
                                                                                           AttitudeProvider attitudeProvider,
                                                                                           T mass,
                                                                                           Frame teme,
                                                                                           T[] parameters)
```
    Selects the extrapolator to use with the selected TLE.
    
    Type Parameters:
    
    T - elements type
    
    Parameters:
    
    tle - the TLE to propagate.
    
    attitudeProvider - provider for attitude computation
    
    mass - spacecraft mass (kg)
    
    teme - the TEME frame to use for propagation.
    
    parameters - SGP4 and SDP4 model parameters
    
    Returns:
    
    the correct propagator.
  - getMU
```
public static double getMU()
```
    Get the Earth gravity coefficient used for TLE propagation.
    
    Returns:
    
    the Earth gravity coefficient.
  - getPVCoordinates
```
public FieldPVCoordinates<T> getPVCoordinates(FieldAbsoluteDate<T> date,
                                              T[] parameters)
```
    Get the extrapolated position and velocity from an initial TLE.
    
    Parameters:
    
    date - the final date
    
    parameters - values of the model
    
    Returns:
    
    the final PVCoordinates
  - getParametersDrivers
```
public List<ParameterDriver> getParametersDrivers()
```
    Get the parameters driver for propagation model.
    
    Specified by:
    
    getParametersDrivers in class FieldAbstractAnalyticalPropagator<T extends CalculusFieldElement<T>>
    
    Returns:
    
    drivers for propagation model
  - sxpInitialize
```
protected abstract void sxpInitialize(T[] parameters)
```
    Initialization proper to each propagator (SGP or SDP).
    
    Parameters:
    
    parameters - model parameters
  - sxpPropagate
```
protected abstract void sxpPropagate(T t,
                                     T[] parameters)
```
    Propagation proper to each propagator (SGP or SDP).
    
    Parameters:
    
    t - the offset from initial epoch (min)
    
    parameters - model parameters
  - resetInitialState
```
public void resetInitialState(FieldSpacecraftState<T> state)
```
    Reset the propagator initial state.
    For TLE propagator, calling this method is only recommended for covariance propagation when the new state differs from the previous one by only adding the additional state containing the derivatives.
    
    Specified by:
    
    resetInitialState in interface FieldPropagator<T extends CalculusFieldElement<T>>
    
    Overrides:
    
    resetInitialState in class FieldAbstractPropagator<T extends CalculusFieldElement<T>>
    
    Parameters:
    
    state - new initial state to consider
  - resetIntermediateState
```
protected void resetIntermediateState(FieldSpacecraftState<T> state,
                                      boolean forward)
```
    Reset an intermediate state.
    
    Specified by:
    
    resetIntermediateState in class FieldAbstractAnalyticalPropagator<T extends CalculusFieldElement<T>>
    
    Parameters:
    
    state - new intermediate state to consider
    
    forward - if true, the intermediate state is valid for propagations after itself
  - getMass
```
protected T getMass(FieldAbsoluteDate<T> date)
```
    Get the mass.
    
    Specified by:
    
    getMass in class FieldAbstractAnalyticalPropagator<T extends CalculusFieldElement<T>>
    
    Parameters:
    
    date - target date for the orbit
    
    Returns:
    
    mass mass
  - propagateOrbit
```
public FieldOrbit<T> propagateOrbit(FieldAbsoluteDate<T> date,
                                    T[] parameters)
```
    Extrapolate an orbit up to a specific target date.
    
    Specified by:
    
    propagateOrbit in class FieldAbstractAnalyticalPropagator<T extends CalculusFieldElement<T>>
    
    Parameters:
    
    date - target date for the orbit
    
    parameters - model parameters
    
    Returns:
    
    extrapolated parameters
  - getTLE
```
public FieldTLE<T> getTLE()
```
    Get the underlying TLE.
    
    Returns:
    
    underlying TLE
  - getFrame
```
public Frame getFrame()
```
    Get the frame in which the orbit is propagated.
    The propagation frame is the definition frame of the initial state, so this method should be called after this state has been set, otherwise it may return null.
    
    Specified by:
    
    getFrame in interface FieldPropagator<T extends CalculusFieldElement<T>>
    
    Overrides:
    
    getFrame in class FieldAbstractPropagator<T extends CalculusFieldElement<T>>
    
    Returns:
    
    frame in which the orbit is propagated
    
    See Also:
    
    FieldPropagator.resetInitialState(FieldSpacecraftState)

Class FieldTLEPropagator<T extends CalculusFieldElement<T>>

Field Summary

Fields inherited from interface org.orekit.propagation.FieldPropagator

Constructor Summary

Method Summary

Methods inherited from class org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator

Methods inherited from class org.orekit.propagation.FieldAbstractPropagator

Methods inherited from class java.lang.Object

Methods inherited from interface org.orekit.propagation.FieldPropagator

Field Detail

tle

utc

xnode

a

e

i

omega

xl

a0dp

xn0dp

cosi0

theta2

sini0

xmdot

omgdot

xnodot

e0sq

beta02

beta0

perige

etasq

eeta

s4

tsi

eta

coef

coef1

c1

c2

c4

xnodcf

t2cof

Constructor Detail

FieldTLEPropagator

FieldTLEPropagator

Method Detail

selectExtrapolator

selectExtrapolator

selectExtrapolator

selectExtrapolator

getMU

getPVCoordinates

getParametersDrivers

sxpInitialize

sxpPropagate

resetInitialState

resetIntermediateState

getMass

propagateOrbit

getTLE

getFrame