org.orekit.propagation.semianalytical.dsst.utilities

Class CoefficientsFactory

java.lang.Object

org.orekit.propagation.semianalytical.dsst.utilities.CoefficientsFactory

public class CoefficientsFactory
extends Object

This class is designed to provide coefficient from the DSST theory.

Author:

Romain Di Costanzo

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CoefficientsFactory.NSKey Key formed by two integer values.

Method Summary

Modifier and Type	Method and Description
static double[][]	computeGsHs(double k, double h, double alpha, double beta, int order) Compute recursively Gs and Hs polynomials from equation 3.1-(5).
static <T extends RealFieldElement<T>> T[][]	computeGsHs(T k, T h, T alpha, T beta, int order, Field<T> field) Compute recursively Gs and Hs polynomials from equation 3.1-(5).
static double[][]	computeQns(double gamma, int nMax, int sMax) Compute the Qn,s coefficients evaluated at γ from the recurrence formula 2.8.3-(2).
static <T extends RealFieldElement<T>> T[][]	computeQns(T gamma, int nMax, int sMax) Compute the Qn,s coefficients evaluated at γ from the recurrence formula 2.8.3-(2).
static TreeMap<CoefficientsFactory.NSKey,Double>	computeVns(int order) Compute the Vn,s coefficients from 2.8.2-(1)(2).
static double	getVmns(int m, int n, int s) Get the Vn,sm coefficient from Vn,s.

Methods inherited from class java.lang.Object

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

Method Detail

computeQns

public static double[][] computeQns(double gamma,
                                    int nMax,
                                    int sMax)

Compute the Q_n,s coefficients evaluated at γ from the recurrence formula 2.8.3-(2).

Q_n,s coefficients are computed for n = 0 to nMax and s = 0 to sMax + 1 in order to also get the derivative dQ_n,s/dγ = Q(n, s + 1)

Parameters:

gamma - γ angle

nMax - n max value

sMax - s max value

Returns:

Q_n,s coefficients array

computeQns

public static <T extends RealFieldElement<T>> T[][] computeQns(T gamma,
                                                               int nMax,
                                                               int sMax)

Compute the Q_n,s coefficients evaluated at γ from the recurrence formula 2.8.3-(2).

Q_n,s coefficients are computed for n = 0 to nMax and s = 0 to sMax + 1 in order to also get the derivative dQ_n,s/dγ = Q(n, s + 1)

Type Parameters:

T - the type of the field elements

Parameters:

gamma - γ angle

nMax - n max value

sMax - s max value

Returns:

Q_n,s coefficients array

computeGsHs

public static double[][] computeGsHs(double k,
                                     double h,
                                     double alpha,
                                     double beta,
                                     int order)

Compute recursively G_s and H_s polynomials from equation 3.1-(5).

Parameters:

k - x-component of the eccentricity vector

h - y-component of the eccentricity vector

alpha - 1st direction cosine

beta - 2nd direction cosine

order - development order

Returns:

Array of G_s and H_s polynomials for s from 0 to order.
The 1st column contains the G_s values. The 2nd column contains the H_s values.

computeGsHs

public static <T extends RealFieldElement<T>> T[][] computeGsHs(T k,
                                                                T h,
                                                                T alpha,
                                                                T beta,
                                                                int order,
                                                                Field<T> field)

Compute recursively G_s and H_s polynomials from equation 3.1-(5).

Type Parameters:

T - the type of the field elements

Parameters:

k - x-component of the eccentricity vector

h - y-component of the eccentricity vector

alpha - 1st direction cosine

beta - 2nd direction cosine

order - development order

field - field of elements

Returns:

Array of G_s and H_s polynomials for s from 0 to order.
The 1st column contains the G_s values. The 2nd column contains the H_s values.

computeVns

public static TreeMap<CoefficientsFactory.NSKey,Double> computeVns(int order)

Compute the V_n,s coefficients from 2.8.2-(1)(2).

Parameters:

order - Order of the computation. Computation will be done from 0 to order -1

Returns:

Map of the V_{n, s} coefficients

getVmns

public static double getVmns(int m,
                             int n,
                             int s)

Get the V_n,s^m coefficient from V_n,s.
See § 2.8.2 in Danielson paper.

Parameters:

m - m

n - n

s - s

Returns:

The V_{n, s} ^m coefficient