public class BrouwerLyddanePropagatorBuilder extends AbstractPropagatorBuilder
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 M2.
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 closed to the TLE.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.
To estimate the M2 parameter, it is necessary to call the AbstractPropagatorBuilder.getPropagationParametersDrivers() method
as follow:
for (ParameterDriver driver : builder.getPropagationParametersDrivers().getDrivers()) {
if (BrouwerLyddanePropagator.M2_NAME.equals(driver.getName())) {
driver.setSelected(true);
}
}
| Constructor and Description |
|---|
BrouwerLyddanePropagatorBuilder(Orbit templateOrbit,
double referenceRadius,
double mu,
TideSystem tideSystem,
double c20,
double c30,
double c40,
double c50,
OrbitType orbitType,
PositionAngleType positionAngleType,
double positionScale,
double M2)
Build a new instance.
|
BrouwerLyddanePropagatorBuilder(Orbit templateOrbit,
UnnormalizedSphericalHarmonicsProvider provider,
PositionAngleType positionAngleType,
double positionScale,
AttitudeProvider attitudeProvider,
double M2)
Build a new instance.
|
BrouwerLyddanePropagatorBuilder(Orbit templateOrbit,
UnnormalizedSphericalHarmonicsProvider provider,
PositionAngleType positionAngleType,
double positionScale,
double M2)
Build a new instance.
|
| Modifier and Type | Method and Description |
|---|---|
AbstractBatchLSModel |
buildLeastSquaresModel(PropagatorBuilder[] builders,
List<ObservedMeasurement<?>> measurements,
ParameterDriversList estimatedMeasurementsParameters,
ModelObserver observer)
Build a new batch least squares model.
|
BrouwerLyddanePropagator |
buildPropagator(double[] normalizedParameters)
Build a propagator.
|
BrouwerLyddanePropagatorBuilder |
copy()
Create a new instance identical to this one.
|
addAdditionalDerivativesProvider, addSupportedParameters, createInitialOrbit, deselectDynamicParameters, getAdditionalDerivativesProviders, getAttitudeProvider, getFrame, getInitialOrbitDate, getMu, getOrbitalParametersDrivers, getOrbitType, getPositionAngleType, getPositionScale, getPropagationParametersDrivers, getSelectedNormalizedParameters, resetOrbit, setAttitudeProvider, setParameterspublic BrouwerLyddanePropagatorBuilder(Orbit templateOrbit, UnnormalizedSphericalHarmonicsProvider provider, PositionAngleType positionAngleType, double positionScale, double M2)
The template orbit is used as a model to create initial orbit. It defines the
inertial frame, the central attraction coefficient, the orbit type, and is also
used together with the positionScale to convert from the normalized parameters
used by the callers of this builder to the real orbital parameters.
The default attitude provider is aligned with the orbit's inertial frame.
templateOrbit - reference orbit from which real orbits will be built
(note that the mu from this orbit will be overridden with the mu from the
provider)provider - for un-normalized zonal coefficientspositionAngleType - position angle type to usepositionScale - scaling factor used for orbital parameters normalization
(typically set to the expected standard deviation of the position)M2 - value of empirical drag coefficient in rad/s².
If equal to BrouwerLyddanePropagator.M2 drag is not computedBrouwerLyddanePropagatorBuilder(Orbit,
UnnormalizedSphericalHarmonicsProvider, PositionAngleType, double, AttitudeProvider, double)public BrouwerLyddanePropagatorBuilder(Orbit templateOrbit, double referenceRadius, double mu, TideSystem tideSystem, double c20, double c30, double c40, double c50, OrbitType orbitType, PositionAngleType positionAngleType, double positionScale, double M2)
The template orbit is used as a model to create initial orbit. It defines the
inertial frame, the central attraction coefficient, the orbit type, and is also
used together with the positionScale to convert from the normalized parameters used by the
callers of this builder to the real orbital parameters.
templateOrbit - reference orbit from which real orbits will be built
(note that the mu from this orbit will be overridden with the mu from the
provider)referenceRadius - reference radius of the Earth for the potential model (m)mu - central attraction coefficient (m³/s²)tideSystem - tide systemc20 - 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)orbitType - orbit type to usepositionAngleType - position angle type to usepositionScale - scaling factor used for orbital parameters normalization
(typically set to the expected standard deviation of the position)M2 - value of empirical drag coefficient in rad/s².
If equal to BrouwerLyddanePropagator.M2 drag is not computedBrouwerLyddanePropagatorBuilder(Orbit,
UnnormalizedSphericalHarmonicsProvider, PositionAngleType, double, AttitudeProvider, double)public BrouwerLyddanePropagatorBuilder(Orbit templateOrbit, UnnormalizedSphericalHarmonicsProvider provider, PositionAngleType positionAngleType, double positionScale, AttitudeProvider attitudeProvider, double M2)
The template orbit is used as a model to create initial orbit. It defines the
inertial frame, the central attraction coefficient, the orbit type, and is also
used together with the positionScale to convert from the normalized parameters used by the
callers of this builder to the real orbital parameters.
templateOrbit - reference orbit from which real orbits will be built
(note that the mu from this orbit will be overridden with the mu from the
provider)provider - for un-normalized zonal coefficientspositionAngleType - position angle type to usepositionScale - scaling factor used for orbital parameters normalization
(typically set to the expected standard deviation of the position)attitudeProvider - attitude law to useM2 - value of empirical drag coefficient in rad/s².
If equal to BrouwerLyddanePropagator.M2 drag is not computedpublic BrouwerLyddanePropagatorBuilder copy()
public BrouwerLyddanePropagator buildPropagator(double[] normalizedParameters)
normalizedParameters - normalized values for the selected parameterspublic AbstractBatchLSModel buildLeastSquaresModel(PropagatorBuilder[] builders, List<ObservedMeasurement<?>> measurements, ParameterDriversList estimatedMeasurementsParameters, ModelObserver observer)
builders - builders to use for propagationmeasurements - measurementsestimatedMeasurementsParameters - estimated measurements parametersobserver - observer to be notified at model callsCopyright © 2002-2023 CS GROUP. All rights reserved.