PVCoordinates (ORbit Extrapolation KIT 10.1 API)

java.lang.Object
- org.orekit.utils.PVCoordinates

All Implemented Interfaces:

Serializable, TimeShiftable<PVCoordinates>

Direct Known Subclasses:

TimeStampedPVCoordinates
```
public class PVCoordinates
extends Object
implements TimeShiftable<PVCoordinates>, Serializable
```
Simple container for Position/Velocity/Acceleration triplets.
The state can be slightly shifted to close dates. This shift is based on a simple quadratic model. It is not intended as a replacement for proper orbit propagation (it is not even Keplerian!) but should be sufficient for either small time shifts or coarse accuracy.

This class is the angular counterpart to AngularCoordinates.

Instances of this class are guaranteed to be immutable.

Author:

Fabien Maussion, Luc Maisonobe

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type Field and Description

static PVCoordinates ZERO
Fixed position/velocity at origin (both p, v and a are zero vectors).

Fields
Modifier and Type	Field and Description
`static PVCoordinates`	`ZERO` Fixed position/velocity at origin (both p, v and a are zero vectors).

Constructor Summary

Constructors
Constructor and Description
`PVCoordinates()` Simple constructor.
`PVCoordinates(double a, PVCoordinates pv)` Multiplicative constructor.
`PVCoordinates(double a1, PVCoordinates pv1, double a2, PVCoordinates pv2)` Linear constructor.
`PVCoordinates(double a1, PVCoordinates pv1, double a2, PVCoordinates pv2, double a3, PVCoordinates pv3)` Linear constructor.
`PVCoordinates(double a1, PVCoordinates pv1, double a2, PVCoordinates pv2, double a3, PVCoordinates pv3, double a4, PVCoordinates pv4)` Linear constructor.
`PVCoordinates(FieldVector3D<DerivativeStructure> p)` Builds a PVCoordinates triplet from a `FieldVector3D`<`DerivativeStructure`>.
`PVCoordinates(PVCoordinates start, PVCoordinates end)` Subtractive constructor.
`PVCoordinates(Vector3D position, Vector3D velocity)` Builds a PVCoordinates triplet with zero acceleration.
`PVCoordinates(Vector3D position, Vector3D velocity, Vector3D acceleration)` Builds a PVCoordinates triplet.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static PVCoordinates`	`crossProduct(PVCoordinates pv1, PVCoordinates pv2)` Compute the cross-product of two instances.
`static Vector3D`	`estimateVelocity(Vector3D start, Vector3D end, double dt)` Estimate velocity between two positions.
`Vector3D`	`getAcceleration()` Gets the acceleration.
`Vector3D`	`getAngularVelocity()` Get the angular velocity (spin) of this point as seen from the origin.
`Vector3D`	`getMomentum()` Gets the momentum.
`Vector3D`	`getPosition()` Gets the position.
`Vector3D`	`getVelocity()` Gets the velocity.
`PVCoordinates`	`negate()` Get the opposite of the instance.
`PVCoordinates`	`normalize()` Normalize the position part of the instance.
`PVCoordinates`	`shiftedBy(double dt)` Get a time-shifted state.
`FieldPVCoordinates<DerivativeStructure>`	`toDerivativeStructurePV(int order)` Transform the instance to a `FieldPVCoordinates`<`DerivativeStructure`>.
`FieldVector3D<DerivativeStructure>`	`toDerivativeStructureVector(int order)` Transform the instance to a `FieldVector3D`<`DerivativeStructure`>.
`String`	`toString()` Return a string representation of this position/velocity pair.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - ZERO
```
public static final PVCoordinates ZERO
```
    Fixed position/velocity at origin (both p, v and a are zero vectors).
- Constructor Detail
  - PVCoordinates
```
public PVCoordinates()
```
    Simple constructor.
    Set the Coordinates to default : (0 0 0), (0 0 0), (0 0 0).
  - PVCoordinates
```
public PVCoordinates(Vector3D position,
                     Vector3D velocity)
```
    Builds a PVCoordinates triplet with zero acceleration.
    Acceleration is set to zero
    
    Parameters:
    
    position - the position vector (m)
    
    velocity - the velocity vector (m/s)
  - PVCoordinates
```
public PVCoordinates(Vector3D position,
                     Vector3D velocity,
                     Vector3D acceleration)
```
    Builds a PVCoordinates triplet.
    
    Parameters:
    
    position - the position vector (m)
    
    velocity - the velocity vector (m/s)
    
    acceleration - the acceleration vector (m/s²)
  - PVCoordinates
```
public PVCoordinates(double a,
                     PVCoordinates pv)
```
    Multiplicative constructor.
    Build a PVCoordinates from another one and a scale factor.
    
    The PVCoordinates built will be a * pv
    
    Parameters:
    
    a - scale factor
    
    pv - base (unscaled) PVCoordinates
  - PVCoordinates
```
public PVCoordinates(PVCoordinates start,
                     PVCoordinates end)
```
    Subtractive constructor.
    Build a relative PVCoordinates from a start and an end position.
    
    The PVCoordinates built will be end - start.
    
    Parameters:
    
    start - Starting PVCoordinates
    
    end - ending PVCoordinates
  - PVCoordinates
```
public PVCoordinates(double a1,
                     PVCoordinates pv1,
                     double a2,
                     PVCoordinates pv2)
```
    Linear constructor.
    Build a PVCoordinates from two other ones and corresponding scale factors.
    
    The PVCoordinates built will be a1 * u1 + a2 * u2
    
    Parameters:
    
    a1 - first scale factor
    
    pv1 - first base (unscaled) PVCoordinates
    
    a2 - second scale factor
    
    pv2 - second base (unscaled) PVCoordinates
  - PVCoordinates
```
public PVCoordinates(double a1,
                     PVCoordinates pv1,
                     double a2,
                     PVCoordinates pv2,
                     double a3,
                     PVCoordinates pv3)
```
    Linear constructor.
    Build a PVCoordinates from three other ones and corresponding scale factors.
    
    The PVCoordinates built will be a1 * u1 + a2 * u2 + a3 * u3
    
    Parameters:
    
    a1 - first scale factor
    
    pv1 - first base (unscaled) PVCoordinates
    
    a2 - second scale factor
    
    pv2 - second base (unscaled) PVCoordinates
    
    a3 - third scale factor
    
    pv3 - third base (unscaled) PVCoordinates
  - PVCoordinates
```
public PVCoordinates(double a1,
                     PVCoordinates pv1,
                     double a2,
                     PVCoordinates pv2,
                     double a3,
                     PVCoordinates pv3,
                     double a4,
                     PVCoordinates pv4)
```
    Linear constructor.
    Build a PVCoordinates from four other ones and corresponding scale factors.
    
    The PVCoordinates built will be a1 * u1 + a2 * u2 + a3 * u3 + a4 * u4
    
    Parameters:
    
    a1 - first scale factor
    
    pv1 - first base (unscaled) PVCoordinates
    
    a2 - second scale factor
    
    pv2 - second base (unscaled) PVCoordinates
    
    a3 - third scale factor
    
    pv3 - third base (unscaled) PVCoordinates
    
    a4 - fourth scale factor
    
    pv4 - fourth base (unscaled) PVCoordinates
  - PVCoordinates
```
public PVCoordinates(FieldVector3D<DerivativeStructure> p)
```
    Builds a PVCoordinates triplet from a FieldVector3D<DerivativeStructure>.
    The vector components must have time as their only derivation parameter and have consistent derivation orders.
    
    Parameters:
    
    p - vector with time-derivatives embedded within the coordinates
- Method Detail
  - toDerivativeStructureVector
```
public FieldVector3D<DerivativeStructure> toDerivativeStructureVector(int order)
```
    Transform the instance to a FieldVector3D<DerivativeStructure>.
    The DerivativeStructure coordinates correspond to time-derivatives up to the user-specified order.
    
    Parameters:
    
    order - derivation order for the vector components (must be either 0, 1 or 2)
    
    Returns:
    
    vector with time-derivatives embedded within the coordinates
  - toDerivativeStructurePV
```
public FieldPVCoordinates<DerivativeStructure> toDerivativeStructurePV(int order)
```
    Transform the instance to a FieldPVCoordinates<DerivativeStructure>.
    The DerivativeStructure coordinates correspond to time-derivatives up to the user-specified order. As both the instance components position, velocity and acceleration and the derivatives of the components holds time-derivatives, there are several ways to retrieve these derivatives. If for example the order is set to 2, then both pv.getPosition().getX().getPartialDerivative(2), pv.getVelocity().getX().getPartialDerivative(1) and pv.getAcceleration().getX().getValue() return the exact same value.
    
    If derivation order is 1, the first derivative of acceleration will be computed as a Keplerian-only jerk. If derivation order is 2, the second derivative of velocity (which is also the first derivative of acceleration) will be computed as a Keplerian-only jerk, and the second derivative of acceleration will be computed as a Keplerian-only jounce.
    
    Parameters:
    
    order - derivation order for the vector components (must be either 0, 1 or 2)
    
    Returns:
    
    pv coordinates with time-derivatives embedded within the coordinates
    
    Since:
    
    9.2
  - estimateVelocity
```
public static Vector3D estimateVelocity(Vector3D start,
                                        Vector3D end,
                                        double dt)
```
    Estimate velocity between two positions.
    Estimation is based on a simple fixed velocity translation during the time interval between the two positions.
    
    Parameters:
    
    start - start position
    
    end - end position
    
    dt - time elapsed between the dates of the two positions
    
    Returns:
    
    velocity allowing to go from start to end positions
  - shiftedBy
```
public PVCoordinates shiftedBy(double dt)
```
    Get a time-shifted state.
    The state can be slightly shifted to close dates. This shift is based on a simple Taylor expansion. It is not intended as a replacement for proper orbit propagation (it is not even Keplerian!) but should be sufficient for either small time shifts or coarse accuracy.
    
    Specified by:
    
    shiftedBy in interface TimeShiftable<PVCoordinates>
    
    Parameters:
    
    dt - time shift in seconds
    
    Returns:
    
    a new state, shifted with respect to the instance (which is immutable)
  - getPosition
```
public Vector3D getPosition()
```
    Gets the position.
    
    Returns:
    
    the position vector (m).
  - getVelocity
```
public Vector3D getVelocity()
```
    Gets the velocity.
    
    Returns:
    
    the velocity vector (m/s).
  - getAcceleration
```
public Vector3D getAcceleration()
```
    Gets the acceleration.
    
    Returns:
    
    the acceleration vector (m/s²).
  - getMomentum
```
public Vector3D getMomentum()
```
    Gets the momentum.
    This vector is the p ⊗ v where p is position, v is velocity and ⊗ is cross product. To get the real physical angular momentum you need to multiply this vector by the mass.
    
    The returned vector is recomputed each time this method is called, it is not cached.
    
    Returns:
    
    a new instance of the momentum vector (m²/s).
  - getAngularVelocity
```
public Vector3D getAngularVelocity()
```
    Get the angular velocity (spin) of this point as seen from the origin.
    The angular velocity vector is parallel to the angular momentum and is computed by ω = p × v / ||p||²
    
    Returns:
    
    the angular velocity vector
    
    See Also:
    
    Angular Velocity on Wikipedia
  - negate
```
public PVCoordinates negate()
```
    Get the opposite of the instance.
    
    Returns:
    
    a new position-velocity which is opposite to the instance
  - normalize
```
public PVCoordinates normalize()
```
    Normalize the position part of the instance.
    The computed coordinates first component (position) will be a normalized vector, the second component (velocity) will be the derivative of the first component (hence it will generally not be normalized), and the third component (acceleration) will be the derivative of the second component (hence it will generally not be normalized).
    
    Returns:
    
    a new instance, with first component normalized and remaining component computed to have consistent derivatives
  - crossProduct
```
public static PVCoordinates crossProduct(PVCoordinates pv1,
                                         PVCoordinates pv2)
```
    Compute the cross-product of two instances.
    
    Parameters:
    
    pv1 - first instances
    
    pv2 - second instances
    
    Returns:
    
    the cross product v1 ^ v2 as a new instance
  - toString
```
public String toString()
```
    Return a string representation of this position/velocity pair.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    string representation of this position/velocity pair

Class PVCoordinates

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ZERO

Constructor Detail

PVCoordinates

PVCoordinates

PVCoordinates

PVCoordinates

PVCoordinates

PVCoordinates

PVCoordinates

PVCoordinates

PVCoordinates

Method Detail

toDerivativeStructureVector

toDerivativeStructurePV

estimateVelocity

shiftedBy

getPosition

getVelocity

getAcceleration

getMomentum

getAngularVelocity

negate

normalize

crossProduct

toString