public class SpacecraftState extends Object implements TimeStamped, TimeShiftable<SpacecraftState>, Serializable
It contains an Orbit
, or an AbsolutePVCoordinates
if there
is no definite central body, plus the current mass and attitude at the intrinsic
AbsoluteDate
. Quantities are guaranteed to be consistent in terms
of date and reference frame. The spacecraft state may also contain additional
states, which are simply named double arrays which can hold any user-defined
data.
The state can be slightly shifted to close dates. This actual shift varies
between Orbit
and AbsolutePVCoordinates
.
For attitude it is a linear extrapolation taking the spin rate into account
and no mass change. It is not intended as a replacement for proper
orbit and attitude propagation but should be sufficient for either small
time shifts or coarse accuracy.
The instance SpacecraftState
is guaranteed to be immutable.
NumericalPropagator
,
Serialized FormModifier and Type | Field and Description |
---|---|
static double |
DEFAULT_MASS
Default mass.
|
Constructor and Description |
---|
SpacecraftState(AbsolutePVCoordinates absPva)
Build a spacecraft state from position-velocity-acceleration only.
|
SpacecraftState(AbsolutePVCoordinates absPva,
Attitude attitude)
Build a spacecraft state from position-velocity-acceleration and attitude.
|
SpacecraftState(AbsolutePVCoordinates absPva,
Attitude attitude,
double mass)
Build a spacecraft state from position-velocity-acceleration, attitude and mass.
|
SpacecraftState(AbsolutePVCoordinates absPva,
Attitude attitude,
DoubleArrayDictionary additional)
Build a spacecraft state from position-velocity-acceleration, attitude and additional states.
|
SpacecraftState(AbsolutePVCoordinates absPva,
Attitude attitude,
double mass,
DoubleArrayDictionary additional)
Build a spacecraft state from position-velocity-acceleration, attitude, mass and additional states.
|
SpacecraftState(AbsolutePVCoordinates absPva,
Attitude attitude,
double mass,
DoubleArrayDictionary additional,
DoubleArrayDictionary additionalDot)
Build a spacecraft state from position-velocity-acceleration, attitude, mass and additional states and derivatives.
|
SpacecraftState(AbsolutePVCoordinates absPva,
double mass)
Create a new instance from position-velocity-acceleration and mass.
|
SpacecraftState(AbsolutePVCoordinates absPva,
DoubleArrayDictionary additional)
Build a spacecraft state from position-velocity-acceleration and additional states.
|
SpacecraftState(AbsolutePVCoordinates absPva,
double mass,
DoubleArrayDictionary additional)
Create a new instance from position-velocity-acceleration, mass and additional states.
|
SpacecraftState(Orbit orbit)
Build a spacecraft state from orbit only.
|
SpacecraftState(Orbit orbit,
Attitude attitude)
Build a spacecraft state from orbit and attitude.
|
SpacecraftState(Orbit orbit,
Attitude attitude,
double mass)
Build a spacecraft state from orbit, attitude and mass.
|
SpacecraftState(Orbit orbit,
Attitude attitude,
DoubleArrayDictionary additional)
Build a spacecraft state from orbit, attitude and additional states.
|
SpacecraftState(Orbit orbit,
Attitude attitude,
double mass,
DoubleArrayDictionary additional)
Build a spacecraft state from orbit, attitude, mass and additional states.
|
SpacecraftState(Orbit orbit,
Attitude attitude,
double mass,
DoubleArrayDictionary additional,
DoubleArrayDictionary additionalDot)
Build a spacecraft state from orbit, attitude, mass, additional states and derivatives.
|
SpacecraftState(Orbit orbit,
double mass)
Create a new instance from orbit and mass.
|
SpacecraftState(Orbit orbit,
DoubleArrayDictionary additional)
Build a spacecraft state from orbit and additional states.
|
SpacecraftState(Orbit orbit,
double mass,
DoubleArrayDictionary additional)
Create a new instance from orbit, mass and additional states.
|
Modifier and Type | Method and Description |
---|---|
SpacecraftState |
addAdditionalState(String name,
double... value)
Add an additional state.
|
SpacecraftState |
addAdditionalStateDerivative(String name,
double... value)
Add an additional state derivative.
|
void |
ensureCompatibleAdditionalStates(SpacecraftState state)
Check if two instances have the same set of additional states available.
|
double |
getA()
Get the semi-major axis.
|
AbsolutePVCoordinates |
getAbsPVA()
Get the absolute position-velocity-acceleration.
|
double[] |
getAdditionalState(String name)
Get an additional state.
|
double[] |
getAdditionalStateDerivative(String name)
Get an additional state derivative.
|
DoubleArrayDictionary |
getAdditionalStatesDerivatives()
Get an unmodifiable map of additional states derivatives.
|
DoubleArrayDictionary |
getAdditionalStatesValues()
Get an unmodifiable map of additional states.
|
Attitude |
getAttitude()
Get the attitude.
|
AbsoluteDate |
getDate()
Get the date.
|
double |
getE()
Get the eccentricity.
|
double |
getEquinoctialEx()
Get the first component of the eccentricity vector (as per equinoctial parameters).
|
double |
getEquinoctialEy()
Get the second component of the eccentricity vector (as per equinoctial parameters).
|
Frame |
getFrame()
Get the defining frame.
|
double |
getHx()
Get the first component of the inclination vector (as per equinoctial parameters).
|
double |
getHy()
Get the second component of the inclination vector (as per equinoctial parameters).
|
double |
getI()
Get the inclination.
|
double |
getKeplerianMeanMotion()
Get the Keplerian mean motion.
|
double |
getKeplerianPeriod()
Get the Keplerian period.
|
double |
getLE()
Get the eccentric latitude argument (as per equinoctial parameters).
|
double |
getLM()
Get the mean longitude argument (as per equinoctial parameters).
|
double |
getLv()
Get the true latitude argument (as per equinoctial parameters).
|
double |
getMass()
Gets the current mass.
|
double |
getMu()
Get the central attraction coefficient.
|
Orbit |
getOrbit()
Get the current orbit.
|
org.hipparchus.geometry.euclidean.threed.Vector3D |
getPosition()
Get the position in orbit definition frame.
|
org.hipparchus.geometry.euclidean.threed.Vector3D |
getPosition(Frame outputFrame)
Get the position in given output frame.
|
TimeStampedPVCoordinates |
getPVCoordinates()
Get the
TimeStampedPVCoordinates in orbit definition frame. |
TimeStampedPVCoordinates |
getPVCoordinates(Frame outputFrame)
Get the
TimeStampedPVCoordinates in given output frame. |
boolean |
hasAdditionalState(String name)
Check if an additional state is available.
|
boolean |
hasAdditionalStateDerivative(String name)
Check if an additional state derivative is available.
|
boolean |
isOrbitDefined()
Check if the state contains an orbit part.
|
SpacecraftState |
shiftedBy(double dt)
Get a time-shifted state.
|
StaticTransform |
toStaticTransform()
Compute the static transform from state defining frame to spacecraft frame.
|
String |
toString() |
Transform |
toTransform()
Compute the transform from state defining frame to spacecraft frame.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
durationFrom
public static final double DEFAULT_MASS
public SpacecraftState(Orbit orbit)
Attitude and mass are set to unspecified non-null arbitrary values.
orbit
- the orbitpublic SpacecraftState(Orbit orbit, Attitude attitude) throws IllegalArgumentException
Mass is set to an unspecified non-null arbitrary value.
orbit
- the orbitattitude
- attitudeIllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(Orbit orbit, double mass)
Attitude law is set to an unspecified default attitude.
orbit
- the orbitmass
- the mass (kg)public SpacecraftState(Orbit orbit, Attitude attitude, double mass) throws IllegalArgumentException
orbit
- the orbitattitude
- attitudemass
- the mass (kg)IllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(Orbit orbit, DoubleArrayDictionary additional)
Attitude and mass are set to unspecified non-null arbitrary values.
orbit
- the orbitadditional
- additional statespublic SpacecraftState(Orbit orbit, Attitude attitude, DoubleArrayDictionary additional) throws IllegalArgumentException
Mass is set to an unspecified non-null arbitrary value.
orbit
- the orbitattitude
- attitudeadditional
- additional statesIllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(Orbit orbit, double mass, DoubleArrayDictionary additional)
Attitude law is set to an unspecified default attitude.
orbit
- the orbitmass
- the mass (kg)additional
- additional statespublic SpacecraftState(Orbit orbit, Attitude attitude, double mass, DoubleArrayDictionary additional) throws IllegalArgumentException
orbit
- the orbitattitude
- attitudemass
- the mass (kg)additional
- additional states (may be null if no additional states are available)IllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(Orbit orbit, Attitude attitude, double mass, DoubleArrayDictionary additional, DoubleArrayDictionary additionalDot) throws IllegalArgumentException
orbit
- the orbitattitude
- attitudemass
- the mass (kg)additional
- additional states (may be null if no additional states are available)additionalDot
- additional states derivatives (may be null if no additional states derivatives are available)IllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(AbsolutePVCoordinates absPva)
Attitude and mass are set to unspecified non-null arbitrary values.
absPva
- position-velocity-accelerationpublic SpacecraftState(AbsolutePVCoordinates absPva, Attitude attitude) throws IllegalArgumentException
Mass is set to an unspecified non-null arbitrary value.
absPva
- position-velocity-accelerationattitude
- attitudeIllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(AbsolutePVCoordinates absPva, double mass)
Attitude law is set to an unspecified default attitude.
absPva
- position-velocity-accelerationmass
- the mass (kg)public SpacecraftState(AbsolutePVCoordinates absPva, Attitude attitude, double mass) throws IllegalArgumentException
absPva
- position-velocity-accelerationattitude
- attitudemass
- the mass (kg)IllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(AbsolutePVCoordinates absPva, DoubleArrayDictionary additional)
Attitude and mass are set to unspecified non-null arbitrary values.
absPva
- position-velocity-accelerationadditional
- additional statespublic SpacecraftState(AbsolutePVCoordinates absPva, Attitude attitude, DoubleArrayDictionary additional) throws IllegalArgumentException
Mass is set to an unspecified non-null arbitrary value.
absPva
- position-velocity-accelerationattitude
- attitudeadditional
- additional statesIllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(AbsolutePVCoordinates absPva, double mass, DoubleArrayDictionary additional)
Attitude law is set to an unspecified default attitude.
absPva
- position-velocity-accelerationmass
- the mass (kg)additional
- additional statespublic SpacecraftState(AbsolutePVCoordinates absPva, Attitude attitude, double mass, DoubleArrayDictionary additional) throws IllegalArgumentException
absPva
- position-velocity-accelerationattitude
- attitudemass
- the mass (kg)additional
- additional states (may be null if no additional states are available)IllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState(AbsolutePVCoordinates absPva, Attitude attitude, double mass, DoubleArrayDictionary additional, DoubleArrayDictionary additionalDot) throws IllegalArgumentException
absPva
- position-velocity-accelerationattitude
- attitudemass
- the mass (kg)additional
- additional states (may be null if no additional states are available)additionalDot
- additional states derivatives(may be null if no additional states derivatives are available)IllegalArgumentException
- if orbit and attitude dates
or frames are not equalpublic SpacecraftState addAdditionalState(String name, double... value)
SpacecraftState
instances are immutable,
so this method does not change the instance, but rather
creates a new instance, which has the same orbit, attitude, mass
and additional states as the original instance, except it also
has the specified state. If the original instance already had an
additional state with the same name, it will be overridden. If it
did not have any additional state with that name, the new instance
will have one more additional state than the original instance.
name
- name of the additional state (names containing "orekit"
with any case are reserved for the library internal use)value
- value of the additional statehasAdditionalState(String)
,
getAdditionalState(String)
,
getAdditionalStatesValues()
public SpacecraftState addAdditionalStateDerivative(String name, double... value)
SpacecraftState
instances are immutable,
so this method does not change the instance, but rather
creates a new instance, which has the same components as the original
instance, except it also has the specified state derivative. If the
original instance already had an additional state derivative with the
same name, it will be overridden. If it did not have any additional
state derivative with that name, the new instance will have one more
additional state derivative than the original instance.
name
- name of the additional state derivative (names containing "orekit"
with any case are reserved for the library internal use)value
- value of the additional state derivativehasAdditionalStateDerivative(String)
,
getAdditionalStateDerivative(String)
,
getAdditionalStatesDerivatives()
public boolean isOrbitDefined()
A state contains either an absolute
position-velocity-acceleration
or an orbit
.
getOrbit()
will not throw an exception), or false if the state contains an
absolut position-velocity-acceleration (in which case getAbsPVA()
will not throw an exception)public SpacecraftState shiftedBy(double dt)
The state can be slightly shifted to close dates. This shift is based on simple models. For orbits, the model is a Keplerian one if no derivatives are available in the orbit, or Keplerian plus quadratic effect of the non-Keplerian acceleration if derivatives are available. For attitude, a polynomial model is used. Neither mass nor additional states change. Shifting is not intended as a replacement for proper orbit and attitude propagation but should be sufficient for small time shifts or coarse accuracy.
As a rough order of magnitude, the following table shows the extrapolation
errors obtained between this simple shift method and an numerical
propagator
for a low Earth Sun Synchronous Orbit, with a 20x20 gravity field,
Sun and Moon third bodies attractions, drag and solar radiation pressure.
Beware that these results will be different for other orbits.
interpolation time (s) | position error without derivatives (m) | position error with derivatives (m) |
---|---|---|
60 | 18 | 1.1 |
120 | 72 | 9.1 |
300 | 447 | 140 |
600 | 1601 | 1067 |
900 | 3141 | 3307 |
shiftedBy
in interface TimeShiftable<SpacecraftState>
dt
- time shift in secondspublic AbsolutePVCoordinates getAbsPVA() throws OrekitIllegalStateException
A state contains either an absolute
position-velocity-acceleration
or an orbit
. Which
one is present can be checked using isOrbitDefined()
.
OrekitIllegalStateException
- if position-velocity-acceleration is null,
which mean the state rather contains an Orbit
isOrbitDefined()
,
getOrbit()
public Orbit getOrbit() throws OrekitIllegalStateException
A state contains either an absolute
position-velocity-acceleration
or an orbit
. Which
one is present can be checked using isOrbitDefined()
.
OrekitIllegalStateException
- if orbit is null,
which means the state rather contains an absolute
position-velocity-acceleration
isOrbitDefined()
,
getAbsPVA()
public AbsoluteDate getDate()
getDate
in interface TimeStamped
public Frame getFrame()
public boolean hasAdditionalState(String name)
name
- name of the additional stateaddAdditionalState(String, double[])
,
getAdditionalState(String)
,
getAdditionalStatesValues()
public boolean hasAdditionalStateDerivative(String name)
name
- name of the additional state derivativeaddAdditionalStateDerivative(String, double[])
,
getAdditionalStateDerivative(String)
,
getAdditionalStatesDerivatives()
public void ensureCompatibleAdditionalStates(SpacecraftState state) throws org.hipparchus.exception.MathIllegalStateException
Only the names and dimensions of the additional states are compared, not their values.
state
- state to compare to instanceorg.hipparchus.exception.MathIllegalStateException
- if an additional state does not have
the same dimension in both statespublic double[] getAdditionalState(String name)
name
- name of the additional stateaddAdditionalState(String, double[])
,
hasAdditionalState(String)
,
getAdditionalStatesValues()
public double[] getAdditionalStateDerivative(String name)
name
- name of the additional state derivativeaddAdditionalStateDerivative(String, double[])
,
hasAdditionalStateDerivative(String)
,
getAdditionalStatesDerivatives()
public DoubleArrayDictionary getAdditionalStatesValues()
addAdditionalState(String, double[])
,
hasAdditionalState(String)
,
getAdditionalState(String)
public DoubleArrayDictionary getAdditionalStatesDerivatives()
addAdditionalStateDerivative(String, double[])
,
hasAdditionalStateDerivative(String)
,
getAdditionalStateDerivative(String)
public Transform toTransform()
The spacecraft frame origin is at the point defined by the orbit (or absolute position-velocity-acceleration), and its orientation is defined by the attitude.
public StaticTransform toStaticTransform()
toTransform()
public double getMu()
public double getKeplerianPeriod()
The Keplerian period is computed directly from semi major axis and central acceleration constant.
public double getKeplerianMeanMotion()
The Keplerian mean motion is computed directly from semi major axis and central acceleration constant.
public double getA()
public double getEquinoctialEx()
getE()
public double getEquinoctialEy()
getE()
public double getHx()
getI()
public double getHy()
getI()
public double getLv()
public double getLE()
public double getLM()
public double getE()
getEquinoctialEx()
,
getEquinoctialEy()
public double getI()
public org.hipparchus.geometry.euclidean.threed.Vector3D getPosition()
getPVCoordinates()
public TimeStampedPVCoordinates getPVCoordinates()
TimeStampedPVCoordinates
in orbit definition frame.
Compute the position and velocity of the satellite. This method caches its
results, and recompute them only when the method is called with a new value
for mu. The result is provided as a reference to the internally cached
TimeStampedPVCoordinates
, so the caller is responsible to copy it in a separate
TimeStampedPVCoordinates
if it needs to keep the value for a while.
public org.hipparchus.geometry.euclidean.threed.Vector3D getPosition(Frame outputFrame)
outputFrame
- frame in which position should be definedgetPVCoordinates(Frame)
public TimeStampedPVCoordinates getPVCoordinates(Frame outputFrame)
TimeStampedPVCoordinates
in given output frame.
Compute the position and velocity of the satellite. This method caches its
results, and recompute them only when the method is called with a new value
for mu. The result is provided as a reference to the internally cached
TimeStampedPVCoordinates
, so the caller is responsible to copy it in a separate
TimeStampedPVCoordinates
if it needs to keep the value for a while.
outputFrame
- frame in which coordinates should be definedpublic Attitude getAttitude()
public double getMass()
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