fr.cnes.sirius.patrius.stela.forces.radiation

Class SRPSquaring

java.lang.Object

fr.cnes.sirius.patrius.stela.forces.AbstractStelaGaussContribution

fr.cnes.sirius.patrius.stela.forces.radiation.SRPSquaring

All Implemented Interfaces:

StelaForceModel

public class SRPSquaring
extends AbstractStelaGaussContribution

Class representing the srp gauss force model for STELA

Since:

1.3

Version:

$Id$

Author:

Rami Houdroge

See Also:

AbstractStelaGaussContribution

Concurrency :

conditionally thread-safe

Concurrency comment :

thread-safe if the given sun is thread-safe

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_QUADRATURE_POINTS Default quadrature points

Fields inherited from class fr.cnes.sirius.patrius.stela.forces.AbstractStelaGaussContribution

dPert

Constructor Summary

Constructors

Constructor and Description
SRPSquaring(RadiationSensitive radiativeSpacecraft, int quadraturePoints, PVCoordinatesProvider sunBody, double earthRadius) Create an instance with an assembly and a number of points.
SRPSquaring(RadiationSensitive radiativeSpacecraft, int quadraturePoints, PVCoordinatesProvider sunBody, double earthRadius, double dRef, double pRef) Create an instance with an assembly and a number of points.
SRPSquaring(RadiationSensitive radiativeSpacecraft, PVCoordinatesProvider sunBody, double earthRadius) Create an instance with an assembly and a number of points.

Method Summary

Modifier and Type	Method and Description
Vector3D	computeAcceleration(StelaEquinoctialOrbit orbit, PVCoordinates satSunVector) Compute the acceleration due to the force.
protected double[]	computeInOutTrueAnom(StelaEquinoctialOrbit orbit, PVCoordinates sunPV) Computation of in and out true anomalies of the shadowed part of the orbit.
double[][]	computePartialDerivatives(StelaEquinoctialOrbit orbit) Compute the partial derivatives for a given spacecraft state.
double[]	computePerturbation(StelaEquinoctialOrbit orbit, OrbitNatureConverter converter) Compute the dE/dt force derivatives for a given spacecraft state.
double[]	computeShortPeriods(StelaEquinoctialOrbit orbit) Compute the short periodic variations for a given spacecraft state.
protected double[]	computeSunBetaPhi(StelaEquinoctialOrbit orbit, PVCoordinates sunPV) Computation of Sun's right ascension (φ) and declination (β) wrt the orbit plane.
protected int	getPolyOrder(double a0, double a1, double a2, double a3, double a4) Determination of the order of A4*s4 + A3*s3 + A2*s2 + A1*s1 + A0 .
protected double[]	rootsFiltering(Complex[] roots) Filtering of computed roots.
protected Complex[]	solveBiquadratic(double c4, double c2, double c0) Solves the equation c4x4 + c2x2 + c0 = 0.
protected Complex[]	solvePolyDeg2(Complex c2, Complex c1, Complex c0) Solves the complex equation c2x2 + c1x + c0 = 0.
protected Complex[]	solvePolyDeg3(double c3, double c2, double c1, double c0) Solves the equation c3x3 + c2x2 + c1x + c0 = 0.
protected Complex[]	solvePolyDeg4(double c4, double c3, double c2, double c1, double c0) Solves the equation c4x4 + c3x3 + c2x2 + c1x + c0 = 0.

Methods inherited from class fr.cnes.sirius.patrius.stela.forces.AbstractStelaGaussContribution

computeGaussDerivativeEquations, computeGaussEquations, getdPert, getType

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_QUADRATURE_POINTS

public static final int DEFAULT_QUADRATURE_POINTS

Default quadrature points

See Also:

Constant Field Values

Constructor Detail

SRPSquaring

public SRPSquaring(RadiationSensitive radiativeSpacecraft,
                   PVCoordinatesProvider sunBody,
                   double earthRadius)

Create an instance with an assembly and a number of points. Reference normalized flux is that of STELA.

Parameters:

radiativeSpacecraft - the radiative spacecraft

sunBody - the sun

earthRadius - earth's equatorial radius

SRPSquaring

public SRPSquaring(RadiationSensitive radiativeSpacecraft,
                   int quadraturePoints,
                   PVCoordinatesProvider sunBody,
                   double earthRadius)

Create an instance with an assembly and a number of points. Reference normalized flux is that of STELA.

Parameters:

radiativeSpacecraft - the radiative spacecraft

quadraturePoints - the number of points for quadrature

sunBody - the sun

earthRadius - earth's equatorial radius

SRPSquaring

public SRPSquaring(RadiationSensitive radiativeSpacecraft,
                   int quadraturePoints,
                   PVCoordinatesProvider sunBody,
                   double earthRadius,
                   double dRef,
                   double pRef)

Create an instance with an assembly and a number of points.

Parameters:

radiativeSpacecraft - the radiative spacecraft

quadraturePoints - the number of points for quadrature

sunBody - the sun

earthRadius - earth's equatorial radius

dRef - reference distance for the solar radiation pressure (m)

pRef - reference solar radiation pressure at dRef (N/m²)

Method Detail

computePerturbation

public double[] computePerturbation(StelaEquinoctialOrbit orbit,
                                    OrbitNatureConverter converter)
                             throws PatriusException

Compute the dE/dt force derivatives for a given spacecraft state.

Specified by:

computePerturbation in class AbstractStelaGaussContribution

Parameters:

orbit - current orbit information: date, kinematics

converter - mean / osculating parameters converter

Returns:

the perturbation dE/dt for the current force

Throws:

PatriusException - if perturbation computation fails

computeAcceleration

public Vector3D computeAcceleration(StelaEquinoctialOrbit orbit,
                                    PVCoordinates satSunVector)
                             throws PatriusException

Compute the acceleration due to the force.

Parameters:

orbit - an orbit

satSunVector - Satellite - Sun vector coordinates

Returns:

acceleration in the orbit reference frame

Throws:

PatriusException - if some specific error occurs

computeInOutTrueAnom

protected double[] computeInOutTrueAnom(StelaEquinoctialOrbit orbit,
                                        PVCoordinates sunPV)
                                 throws PatriusException

Computation of in and out true anomalies of the shadowed part of the orbit.

Parameters:

orbit - an orbit

sunPV - Sun coordinates

Returns:

[ν_in, ν_out] : in and out true anomalies

Throws:

PatriusException - if computation of declination and right ascension of the Sun fails

rootsFiltering

protected double[] rootsFiltering(Complex[] roots)

Filtering of computed roots.

Parameters:

roots - roots of a polynomial

Returns:

[α_in , α_out], with α_in < α_out

solvePolyDeg2

protected Complex[] solvePolyDeg2(Complex c2,
                                  Complex c1,
                                  Complex c0)

Solves the complex equation c₂x² + c₁x + c₀ = 0.

Parameters:

c2 - coefficient of order 2

c1 - coefficient of order 1

c0 - coefficient of order 0

Returns:

[x₀, x₁] where x₀ and x₁ are the roots of the equation

solvePolyDeg3

protected Complex[] solvePolyDeg3(double c3,
                                  double c2,
                                  double c1,
                                  double c0)

Solves the equation c₃x³ + c₂x² + c₁x + c₀ = 0.

Parameters:

c3 - coefficient of order 3

c2 - coefficient of order 2

c1 - coefficient of order 1

c0 - coefficient of order 0

Returns:

[x₀, x₁, x₂] where x₀ , x₁ and x₂ are the roots of the equation

solveBiquadratic

protected Complex[] solveBiquadratic(double c4,
                                     double c2,
                                     double c0)

Solves the equation c₄x⁴ + c₂x² + c₀ = 0.

Parameters:

c4 - coefficient of order 4

c2 - coefficient of order 2

c0 - coefficient of order 0

Returns:

[x₀, x₁, x₂, x₃] where x₀ , x₁ , x₂ and x₃ are the roots of the equation

solvePolyDeg4

protected Complex[] solvePolyDeg4(double c4,
                                  double c3,
                                  double c2,
                                  double c1,
                                  double c0)

Solves the equation c₄x⁴ + c₃x³ + c₂x² + c₁x + c₀ = 0.

Parameters:

c4 - coefficient of order 4

c3 - coefficient of order 3

c2 - coefficient of order 2

c1 - coefficient of order 1

c0 - coefficient of order 0

Returns:

[x₀, x₁, x₂, x₃] where x₀ , x₁ , x₂ and x₃ are the roots of the equation

getPolyOrder

protected int getPolyOrder(double a0,
                           double a1,
                           double a2,
                           double a3,
                           double a4)

Determination of the order of A₄*s⁴ + A₃*s³ + A₂*s² + A₁*s¹ + A₀ .

Parameters:

a0 - coefficient of order 0

a1 - coefficient of order 1

a2 - coefficient of order 2

a3 - coefficient of order 3

a4 - coefficient of order 4

Returns:

the polynomial order

computeSunBetaPhi

protected double[] computeSunBetaPhi(StelaEquinoctialOrbit orbit,
                                     PVCoordinates sunPV)
                              throws PatriusException

Computation of Sun's right ascension (φ) and declination (β) wrt the orbit plane.

Parameters:

orbit - orbit

sunPV - the sun PV coordinates

Returns:

[β,φ]

Throws:

PatriusException - if sun position cannot be computed raised if beta computation fails

computeShortPeriods

public double[] computeShortPeriods(StelaEquinoctialOrbit orbit)
                             throws PatriusException

Compute the short periodic variations for a given spacecraft state.

Parameters:

orbit - current orbit information: date, kinematics

Returns:

the short periodic variations of the current force

Throws:

PatriusException - if short periods computation fails

computePartialDerivatives

public double[][] computePartialDerivatives(StelaEquinoctialOrbit orbit)
                                     throws PatriusException

Compute the partial derivatives for a given spacecraft state.

Parameters:

orbit - current orbit information: date, kinematics

Returns:

the partial derivatives of the current force

Throws:

PatriusException - if partial derivatives computation fails