Class FieldEquinoctialOrbit<T extends CalculusFieldElement<T>>

  • Type Parameters:
    T - type of the field elements
    All Implemented Interfaces:
    PositionAngleBased, FieldTimeShiftable<FieldOrbit<T>,​T>, FieldTimeStamped<T>, TimeShiftable<FieldOrbit<T>>, FieldPVCoordinatesProvider<T>

    public class FieldEquinoctialOrbit<T extends CalculusFieldElement<T>>
    extends FieldOrbit<T>
    implements PositionAngleBased
    This class handles equinoctial orbital parameters, which can support both circular and equatorial orbits.

    The parameters used internally are the equinoctial elements which can be related to Keplerian elements as follows:

         a
         ex = e cos(ω + Ω)
         ey = e sin(ω + Ω)
         hx = tan(i/2) cos(Ω)
         hy = tan(i/2) sin(Ω)
         lv = v + ω + Ω
       
    where ω stands for the Perigee Argument and Ω stands for the Right Ascension of the Ascending Node.

    The conversion equations from and to Keplerian elements given above hold only when both sides are unambiguously defined, i.e. when orbit is neither equatorial nor circular. When orbit is either equatorial or circular, the equinoctial parameters are still unambiguously defined whereas some Keplerian elements (more precisely ω and Ω) become ambiguous. For this reason, equinoctial parameters are the recommended way to represent orbits. Note however than the present implementation does not handle non-elliptical cases.

    The instance EquinoctialOrbit is guaranteed to be immutable.

    Since:
    9.0
    Author:
    Mathieu Roméro, Luc Maisonobe, Guylaine Prat, Fabien Maussion, Véronique Pommier-Maurussane
    See Also:
    Orbit, KeplerianOrbit, CircularOrbit, CartesianOrbit
    • Constructor Detail

      • FieldEquinoctialOrbit

        public FieldEquinoctialOrbit​(T a,
                                     T ex,
                                     T ey,
                                     T hx,
                                     T hy,
                                     T l,
                                     PositionAngleType type,
                                     Frame frame,
                                     FieldAbsoluteDate<T> date,
                                     T mu)
                              throws IllegalArgumentException
        Creates a new instance.
        Parameters:
        a - semi-major axis (m)
        ex - e cos(ω + Ω), first component of eccentricity vector
        ey - e sin(ω + Ω), second component of eccentricity vector
        hx - tan(i/2) cos(Ω), first component of inclination vector
        hy - tan(i/2) sin(Ω), second component of inclination vector
        l - (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)
        type - type of longitude argument
        frame - the frame in which the parameters are defined (must be a pseudo-inertial frame)
        date - date of the orbital parameters
        mu - central attraction coefficient (m³/s²)
        Throws:
        IllegalArgumentException - if eccentricity is equal to 1 or larger or if frame is not a pseudo-inertial frame
      • FieldEquinoctialOrbit

        public FieldEquinoctialOrbit​(T a,
                                     T ex,
                                     T ey,
                                     T hx,
                                     T hy,
                                     T l,
                                     T aDot,
                                     T exDot,
                                     T eyDot,
                                     T hxDot,
                                     T hyDot,
                                     T lDot,
                                     PositionAngleType type,
                                     Frame frame,
                                     FieldAbsoluteDate<T> date,
                                     T mu)
                              throws IllegalArgumentException
        Creates a new instance.
        Parameters:
        a - semi-major axis (m)
        ex - e cos(ω + Ω), first component of eccentricity vector
        ey - e sin(ω + Ω), second component of eccentricity vector
        hx - tan(i/2) cos(Ω), first component of inclination vector
        hy - tan(i/2) sin(Ω), second component of inclination vector
        l - (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)
        aDot - semi-major axis derivative (m/s)
        exDot - d(e cos(ω + Ω))/dt, first component of eccentricity vector derivative
        eyDot - d(e sin(ω + Ω))/dt, second component of eccentricity vector derivative
        hxDot - d(tan(i/2) cos(Ω))/dt, first component of inclination vector derivative
        hyDot - d(tan(i/2) sin(Ω))/dt, second component of inclination vector derivative
        lDot - d(M or E or v) + ω + Ω)/dr, mean, eccentric or true longitude argument derivative (rad/s)
        type - type of longitude argument
        frame - the frame in which the parameters are defined (must be a pseudo-inertial frame)
        date - date of the orbital parameters
        mu - central attraction coefficient (m³/s²)
        Throws:
        IllegalArgumentException - if eccentricity is equal to 1 or larger or if frame is not a pseudo-inertial frame
      • FieldEquinoctialOrbit

        public FieldEquinoctialOrbit​(FieldOrbit<T> op)
        Constructor from any kind of orbital parameters.
        Parameters:
        op - orbital parameters to copy
      • FieldEquinoctialOrbit

        public FieldEquinoctialOrbit​(Field<T> field,
                                     EquinoctialOrbit op)
        Constructor from Field and EquinoctialOrbit.

        Build a FieldEquinoctialOrbit from non-Field EquinoctialOrbit.

        Parameters:
        field - CalculusField to base object on
        op - non-field orbit with only "constant" terms
        Since:
        12.0
      • FieldEquinoctialOrbit

        public FieldEquinoctialOrbit​(Field<T> field,
                                     Orbit op)
        Constructor from Field and Orbit.

        Build a FieldEquinoctialOrbit from any non-Field Orbit.

        Parameters:
        field - CalculusField to base object on
        op - non-field orbit with only "constant" terms
        Since:
        12.0
    • Method Detail

      • getA

        public T getA()
        Get the semi-major axis.

        Note that the semi-major axis is considered negative for hyperbolic orbits.

        Specified by:
        getA in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        semi-major axis (m)
      • getADot

        public T getADot()
        Get the semi-major axis derivative.

        Note that the semi-major axis is considered negative for hyperbolic orbits.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getADot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        semi-major axis derivative (m/s)
      • getEquinoctialEx

        public T getEquinoctialEx()
        Get the first component of the equinoctial eccentricity vector.
        Specified by:
        getEquinoctialEx in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        first component of the equinoctial eccentricity vector
      • getEquinoctialExDot

        public T getEquinoctialExDot()
        Get the first component of the equinoctial eccentricity vector.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getEquinoctialExDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        first component of the equinoctial eccentricity vector
      • getEquinoctialEy

        public T getEquinoctialEy()
        Get the second component of the equinoctial eccentricity vector.
        Specified by:
        getEquinoctialEy in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        second component of the equinoctial eccentricity vector
      • getEquinoctialEyDot

        public T getEquinoctialEyDot()
        Get the second component of the equinoctial eccentricity vector.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getEquinoctialEyDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        second component of the equinoctial eccentricity vector
      • getHx

        public T getHx()
        Get the first component of the inclination vector.
        Specified by:
        getHx in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        first component of the inclination vector
      • getHxDot

        public T getHxDot()
        Get the first component of the inclination vector derivative.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getHxDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        first component of the inclination vector derivative
      • getHy

        public T getHy()
        Get the second component of the inclination vector.
        Specified by:
        getHy in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        second component of the inclination vector
      • getHyDot

        public T getHyDot()
        Get the second component of the inclination vector derivative.
        Specified by:
        getHyDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        second component of the inclination vector derivative
      • getLvDot

        public T getLvDot()
        Get the true longitude argument derivative.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getLvDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        d(v + ω + Ω)/dt true longitude argument derivative (rad/s)
      • getLE

        public T getLE()
        Get the eccentric longitude argument.
        Specified by:
        getLE in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        E + ω + Ω eccentric longitude argument (rad)
      • getLEDot

        public T getLEDot()
        Get the eccentric longitude argument derivative.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getLEDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        d(E + ω + Ω)/dt eccentric longitude argument derivative (rad/s)
      • getLMDot

        public T getLMDot()
        Get the mean longitude argument derivative.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getLMDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        d(M + ω + Ω)/dt mean longitude argument derivative (rad/s)
      • getL

        public T getL​(PositionAngleType type)
        Get the longitude argument.
        Parameters:
        type - type of the angle
        Returns:
        longitude argument (rad)
      • getLDot

        public T getLDot​(PositionAngleType type)
        Get the longitude argument derivative.
        Parameters:
        type - type of the angle
        Returns:
        longitude argument derivative (rad/s)
      • eccentricToTrue

        public static <T extends CalculusFieldElement<T>> T eccentricToTrue​(T lE,
                                                                            T ex,
                                                                            T ey)
        Computes the true longitude argument from the eccentric longitude argument.
        Type Parameters:
        T - Type of the field elements
        Parameters:
        lE - = E + ω + Ω eccentric longitude argument (rad)
        ex - first component of the eccentricity vector
        ey - second component of the eccentricity vector
        Returns:
        the true longitude argument
      • trueToEccentric

        public static <T extends CalculusFieldElement<T>> T trueToEccentric​(T lv,
                                                                            T ex,
                                                                            T ey)
        Computes the eccentric longitude argument from the true longitude argument.
        Type Parameters:
        T - Type of the field elements
        Parameters:
        lv - = v + ω + Ω true longitude argument (rad)
        ex - first component of the eccentricity vector
        ey - second component of the eccentricity vector
        Returns:
        the eccentric longitude argument
      • meanToEccentric

        public static <T extends CalculusFieldElement<T>> T meanToEccentric​(T lM,
                                                                            T ex,
                                                                            T ey)
        Computes the eccentric longitude argument from the mean longitude argument.
        Type Parameters:
        T - Type of the field elements
        Parameters:
        lM - = M + ω + Ω mean longitude argument (rad)
        ex - first component of the eccentricity vector
        ey - second component of the eccentricity vector
        Returns:
        the eccentric longitude argument
      • eccentricToMean

        public static <T extends CalculusFieldElement<T>> T eccentricToMean​(T lE,
                                                                            T ex,
                                                                            T ey)
        Computes the mean longitude argument from the eccentric longitude argument.
        Type Parameters:
        T - Type of the field elements
        Parameters:
        lE - = E + ω + Ω mean longitude argument (rad)
        ex - first component of the eccentricity vector
        ey - second component of the eccentricity vector
        Returns:
        the mean longitude argument
      • getEDot

        public T getEDot()
        Get the eccentricity derivative.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getEDot in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        eccentricity derivative
      • getI

        public T getI()
        Get the inclination.

        If the orbit was created without derivatives, the value returned is null.

        Specified by:
        getI in class FieldOrbit<T extends CalculusFieldElement<T>>
        Returns:
        inclination (rad)
      • addKeplerContribution

        public void addKeplerContribution​(PositionAngleType type,
                                          T gm,
                                          T[] pDot)
        Add the contribution of the Keplerian motion to parameters derivatives

        This method is used by integration-based propagators to evaluate the part of Keplerian motion to evolution of the orbital state.

        Specified by:
        addKeplerContribution in class FieldOrbit<T extends CalculusFieldElement<T>>
        Parameters:
        type - type of the position angle in the state
        gm - attraction coefficient to use
        pDot - array containing orbital state derivatives to update (the Keplerian part must be added to the array components, as the array may already contain some non-zero elements corresponding to non-Keplerian parts)
      • toString

        public String toString()
        Returns a string representation of this equinoctial parameters object.
        Overrides:
        toString in class Object
        Returns:
        a string representation of this object
      • hasRates

        public boolean hasRates()
        Tells whether the instance holds rates (first-order time derivatives) for dependent variables.
        Specified by:
        hasRates in interface PositionAngleBased
        Returns:
        true if and only if holding rates