Package org.orekit.propagation.analytical

Class FieldBrouwerLyddanePropagator<T extends CalculusFieldElement<T>>

  • Type Parameters:
    T - type of the field elements
    All Implemented Interfaces:
    FieldPropagator<T>, FieldPVCoordinatesProvider<T>, ParameterDriversProvider
    public class FieldBrouwerLyddanePropagator<T extends CalculusFieldElement<T>>
extends FieldAbstractAnalyticalPropagator<T>
    This class propagates a FieldSpacecraftState using the analytical Brouwer-Lyddane model (from J2 to J5 zonal harmonics).

    At the opposite of the FieldEcksteinHechlerPropagator, the Brouwer-Lyddane model is suited for elliptical orbits, there is no problem having a rather small eccentricity or inclination (Lyddane helped to solve this issue with the Brouwer model). Singularity for the critical inclination i = 63.4° is avoided using the method developed in Warren Phipps' 1992 thesis.

    By default, Brouwer-Lyddane model considers only the perturbations due to zonal harmonics. However, for low Earth orbits, the magnitude of the perturbative acceleration due to atmospheric drag can be significant. Warren Phipps' 1992 thesis considered the atmospheric drag by time derivatives of the mean mean anomaly using the catch-all coefficient M2Driver. Usually, M2 is adjusted during an orbit determination process and it represents the combination of all unmodeled secular along-track effects (i.e. not just the atmospheric drag). The behavior of M2 is close to the FieldTLE.getBStar() parameter for the TLE. If the value of M2 is equal to 0.0, the along-track secular effects are not considered in the dynamical model. Typical values for M2 are not known. It depends on the orbit type. However, the value of M2 must be very small (e.g. between 1.0e-14 and 1.0e-15). The unit of M2 is rad/s². The along-track effects, represented by the secular rates of the mean semi-major axis and eccentricity, are computed following Eq. 2.38, 2.41, and 2.45 of Warren Phipps' thesis.

    Since:
    11.1
    Author:
    Melina Vanel, Bryan Cazabonne, Pascal Parraud
    See Also:
    "Brouwer, Dirk. Solution of the problem of artificial satellite theory without drag. YALE UNIV NEW HAVEN CT NEW HAVEN United States, 1959.", "Lyddane, R. H. Small eccentricities or inclinations in the Brouwer theory of the artificial satellite. The Astronomical Journal 68 (1963): 555.", "Phipps Jr, Warren E. Parallelization of the Navy Space Surveillance Center (NAVSPASUR) Satellite Model. NAVAL POSTGRADUATE SCHOOL MONTEREY CA, 1992.", "Solomon, Daniel, THE NAVSPASUR Satellite Motion Model, Naval Research Laboratory, August 8, 1991."

    • Constructor Detail

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     double referenceRadius,
                                     T mu,
                                     double c20,
                                     double c30,
                                     double c40,
                                     double c50,
                                     double M2)
        Build a propagator from orbit and potential.

        Mass and attitude provider are set to unspecified non-null arbitrary values.

        The Cn,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients Cn,0 and the Jn one as follows:

        Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½ Cn,0

        Cn,0 = -Jn

        Using this constructor, an initial osculating orbit is considered.

        Parameters:
        initialOrbit - initial orbit
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed
        See Also:
        Constants, FieldBrouwerLyddanePropagator(FieldOrbit, AttitudeProvider, double, CalculusFieldElement, double, double, double, double, double)

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     T mass,
                                     double referenceRadius,
                                     T mu,
                                     double c20,
                                     double c30,
                                     double c40,
                                     double c50,
                                     double M2)
        Build a propagator from orbit, mass and potential.

        Attitude law is set to an unspecified non-null arbitrary value.

        The Cn,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients Cn,0 and the Jn one as follows:

        Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½ Cn,0

        Cn,0 = -Jn

        Using this constructor, an initial osculating orbit is considered.

        Parameters:
        initialOrbit - initial orbit
        mass - spacecraft mass
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed
        See Also:
        FieldBrouwerLyddanePropagator(FieldOrbit, AttitudeProvider, CalculusFieldElement, double, CalculusFieldElement, double, double, double, double, double)

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     AttitudeProvider attitudeProv,
                                     UnnormalizedSphericalHarmonicsProvider provider,
                                     double M2)
        Build a propagator from orbit, attitude provider and potential provider.

        Mass is set to an unspecified non-null arbitrary value.

        Using this constructor, an initial osculating orbit is considered.

        Parameters:
        initialOrbit - initial orbit
        attitudeProv - attitude provider
        provider - for un-normalized zonal coefficients
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     AttitudeProvider attitudeProv,
                                     double referenceRadius,
                                     T mu,
                                     double c20,
                                     double c30,
                                     double c40,
                                     double c50,
                                     double M2)
        Build a propagator from orbit, attitude provider and potential.

        Mass is set to an unspecified non-null arbitrary value.

        The Cn,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients Cn,0 and the Jn one as follows:

        Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½ Cn,0

        Cn,0 = -Jn

        Using this constructor, an initial osculating orbit is considered.

        Parameters:
        initialOrbit - initial orbit
        attitudeProv - attitude provider
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     AttitudeProvider attitudeProv,
                                     T mass,
                                     double referenceRadius,
                                     T mu,
                                     double c20,
                                     double c30,
                                     double c40,
                                     double c50,
                                     double M2)
        Build a propagator from orbit, attitude provider, mass and potential.

        The Cn,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients Cn,0 and the Jn one as follows:

        Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½ Cn,0

        Cn,0 = -Jn

        Using this constructor, an initial osculating orbit is considered.

        Parameters:
        initialOrbit - initial orbit
        attitudeProv - attitude provider
        mass - spacecraft mass
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed
        See Also:
        FieldBrouwerLyddanePropagator(FieldOrbit, AttitudeProvider, CalculusFieldElement, double, CalculusFieldElement, double, double, double, double, PropagationType, double)

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     UnnormalizedSphericalHarmonicsProvider provider,
                                     PropagationType initialType,
                                     double M2)
        Build a propagator from orbit and potential provider.

        Mass and attitude provider are set to unspecified non-null arbitrary values.

        Using this constructor, it is possible to define the initial orbit as a mean Brouwer-Lyddane orbit or an osculating one.

        Parameters:
        initialOrbit - initial orbit
        provider - for un-normalized zonal coefficients
        initialType - initial orbit type (mean Brouwer-Lyddane orbit or osculating orbit)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     AttitudeProvider attitudeProv,
                                     T mass,
                                     UnnormalizedSphericalHarmonicsProvider provider,
                                     PropagationType initialType,
                                     double M2)
        Build a propagator from orbit, attitude provider, mass and potential provider.

        Using this constructor, it is possible to define the initial orbit as a mean Brouwer-Lyddane orbit or an osculating one.

        Parameters:
        initialOrbit - initial orbit
        attitudeProv - attitude provider
        mass - spacecraft mass
        provider - for un-normalized zonal coefficients
        initialType - initial orbit type (mean Brouwer-Lyddane orbit or osculating orbit)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     AttitudeProvider attitudeProv,
                                     T mass,
                                     double referenceRadius,
                                     T mu,
                                     double c20,
                                     double c30,
                                     double c40,
                                     double c50,
                                     PropagationType initialType,
                                     double M2)
        Build a propagator from orbit, attitude provider, mass and potential.

        The Cn,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients Cn,0 and the Jn one as follows:

        Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½ Cn,0

        Cn,0 = -Jn

        Using this constructor, it is possible to define the initial orbit as a mean Brouwer-Lyddane orbit or an osculating one.

        Parameters:
        initialOrbit - initial orbit
        attitudeProv - attitude provider
        mass - spacecraft mass
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        initialType - initial orbit type (mean Brouwer-Lyddane orbit or osculating orbit)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed

      • FieldBrouwerLyddanePropagator

        public FieldBrouwerLyddanePropagator​(FieldOrbit<T> initialOrbit,
                                     AttitudeProvider attitudeProv,
                                     T mass,
                                     double referenceRadius,
                                     T mu,
                                     double c20,
                                     double c30,
                                     double c40,
                                     double c50,
                                     PropagationType initialType,
                                     double M2,
                                     double epsilon,
                                     int maxIterations)
        Build a propagator from orbit, attitude provider, mass and potential.

        The Cn,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients Cn,0 and the Jn one as follows:

        Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½ Cn,0

        Cn,0 = -Jn

        Using this constructor, it is possible to define the initial orbit as a mean Brouwer-Lyddane orbit or an osculating one.

        Parameters:
        initialOrbit - initial orbit
        attitudeProv - attitude provider
        mass - spacecraft mass
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        initialType - initial orbit type (mean Brouwer-Lyddane orbit or osculating orbit)
        M2 - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not computed
        epsilon - convergence threshold for mean parameters conversion
        maxIterations - maximum iterations for mean parameters conversion
        Since:
        11.2

    • Method Detail

      • computeMeanOrbit

        public static <T extends CalculusFieldElement<T>> FieldKeplerianOrbit<T> computeMeanOrbit​(FieldOrbit<T> osculating,
                                                                                          UnnormalizedSphericalHarmonicsProvider provider,
                                                                                          UnnormalizedSphericalHarmonicsProvider.UnnormalizedSphericalHarmonics harmonics,
                                                                                          double M2Value)
        Conversion from osculating to mean orbit.

        Compute mean orbit in a Brouwer-Lyddane sense, corresponding to the osculating SpacecraftState in input.

        Since the osculating orbit is obtained with the computation of short-periodic variation, the resulting output will depend on both the gravity field parameterized in input and the atmospheric drag represented by the m2 parameter.

        The computation is done through a fixed-point iteration process.

        Type Parameters:
        T - type of the filed elements
        Parameters:
        osculating - osculating orbit to convert
        provider - for un-normalized zonal coefficients
        harmonics - provider.onDate(osculating.getDate())
        M2Value - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not considered
        Returns:
        mean orbit in a Brouwer-Lyddane sense
        Since:
        11.2

      • computeMeanOrbit

        public static <T extends CalculusFieldElement<T>> FieldKeplerianOrbit<T> computeMeanOrbit​(FieldOrbit<T> osculating,
                                                                                          UnnormalizedSphericalHarmonicsProvider provider,
                                                                                          UnnormalizedSphericalHarmonicsProvider.UnnormalizedSphericalHarmonics harmonics,
                                                                                          double M2Value,
                                                                                          double epsilon,
                                                                                          int maxIterations)
        Conversion from osculating to mean orbit.

        Compute mean orbit in a Brouwer-Lyddane sense, corresponding to the osculating SpacecraftState in input.

        Since the osculating orbit is obtained with the computation of short-periodic variation, the resulting output will depend on both the gravity field parameterized in input and the atmospheric drag represented by the m2 parameter.

        The computation is done through a fixed-point iteration process.

        Type Parameters:
        T - type of the filed elements
        Parameters:
        osculating - osculating orbit to convert
        provider - for un-normalized zonal coefficients
        harmonics - provider.onDate(osculating.getDate())
        M2Value - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not considered
        epsilon - convergence threshold for mean parameters conversion
        maxIterations - maximum iterations for mean parameters conversion
        Returns:
        mean orbit in a Brouwer-Lyddane sense
        Since:
        11.2

      • computeMeanOrbit

        public static <T extends CalculusFieldElement<T>> FieldKeplerianOrbit<T> computeMeanOrbit​(FieldOrbit<T> osculating,
                                                                                          double referenceRadius,
                                                                                          double mu,
                                                                                          double c20,
                                                                                          double c30,
                                                                                          double c40,
                                                                                          double c50,
                                                                                          double M2Value,
                                                                                          double epsilon,
                                                                                          int maxIterations)
        Conversion from osculating to mean orbit.

        Compute mean orbit in a Brouwer-Lyddane sense, corresponding to the osculating SpacecraftState in input.

        Since the osculating orbit is obtained with the computation of short-periodic variation, the resulting output will depend on both the gravity field parameterized in input and the atmospheric drag represented by the m2 parameter.

        The computation is done through a fixed-point iteration process.

        Type Parameters:
        T - type of the filed elements
        Parameters:
        osculating - osculating orbit to convert
        referenceRadius - reference radius of the Earth for the potential model (m)
        mu - central attraction coefficient (m³/s²)
        c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)
        c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)
        c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)
        c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)
        M2Value - value of empirical drag coefficient in rad/s². If equal to BrouwerLyddanePropagator.M2 drag is not considered
        epsilon - convergence threshold for mean parameters conversion
        maxIterations - maximum iterations for mean parameters conversion
        Returns:
        mean orbit in a Brouwer-Lyddane sense
        Since:
        11.2

      • resetInitialState

        public void resetInitialState​(FieldSpacecraftState<T> state,
                              PropagationType stateType)
        Reset the propagator initial state.
        Parameters:
        state - new initial state to consider
        stateType - mean Brouwer-Lyddane orbit or osculating orbit

      • resetInitialState

        public void resetInitialState​(FieldSpacecraftState<T> state,
                              PropagationType stateType,
                              double epsilon,
                              int maxIterations)
        Reset the propagator initial state.
        Parameters:
        state - new initial state to consider
        stateType - mean Brouwer-Lyddane orbit or osculating orbit
        epsilon - convergence threshold for mean parameters conversion
        maxIterations - maximum iterations for mean parameters conversion
        Since:
        11.2

      • resetIntermediateState

        protected void resetIntermediateState​(FieldSpacecraftState<T> state,
                                      boolean forward,
                                      double epsilon,
                                      int maxIterations)
        Reset an intermediate state.
        Parameters:
        state - new intermediate state to consider
        forward - if true, the intermediate state is valid for propagations after itself
        epsilon - convergence threshold for mean parameters conversion
        maxIterations - maximum iterations for mean parameters conversion
        Since:
        11.2

      • getM2

        public double getM2()
        Get the value of the M2 drag parameter.
        Returns:
        the value of the M2 drag parameter

      • getM2

        public double getM2​(AbsoluteDate date)
        Get the value of the M2 drag parameter.
        Parameters:
        date - date at which the model parameters want to be known
        Returns:
        the value of the M2 drag parameter

      • getParametersDrivers

        public List<ParameterDriver> getParametersDrivers()
        Get the drivers for parameters.
        Returns:
        drivers for parameters