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See:
Description
Interface Summary | |
---|---|
AdditionalStateProvider | This interface represents providers for additional state data beyond SpacecraftState . |
BoundedPropagator | This interface is intended for ephemerides valid only during a time range. |
MassProvider | Interface for spacecraft models that provide the mass. |
MeanOsculatingElementsProvider | Interface for mean/osculating elements converter. |
Propagator | This interface provides a way to propagate an orbit at any time. |
Class Summary | |
---|---|
AbstractPropagator | Common handling of Propagator methods for analytical propagators. |
AnalyticalIntegratedEphemeris | This class stores sequentially generated orbital parameters for later retrieval. |
OsculatingToMeanElementsConverter | This class converts osculating orbital elements into mean elements. |
SimpleMassModel | Simple implementation of MassProvider . |
SpacecraftState | This class is the representation of a complete state holding orbit, attitude for forces and events computation and additional states informations at a given date. |
Enum Summary | |
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ParametersType | Enum class for elements type (mean or osculating). |
This package provides tools to propagate orbital states with different methods.
Propagation is the prediction of the evolution of an initial state.
The initial state and the propagated states are represented in OREKIT by a
SpacecraftState
, which is a
simple container for all needed information at a specific date : mass,
kinematics
,
attitude
,
date
,
frame
. The state provides basic
interpolation features allowing to shift it slightly to close dates. For
more accurate and farthest dates, several full-featured propagators are
available to propagate the state.
KeplerianPropagator
implements the Propagator
interface, which ensures that we can obtain a propagated SpacecraftState
at any time once the instance is initialized with an initial state.
This extrapolation is not a problem with a simple
EquinoctialOrbit
representation: only the mean anomaly value changes.
Propagator
interface.
NumericalPropagator
class realizes the interface between space mechanics and mathematical
resolutions. If its utilization seems difficult on first sight, it is in
fact quite clear and intuitive.
The mathematical problem to integrate is a seven dimension time derivative equations
system. The six first equations are given by the Gauss equations (expressed
in EquinoctialOrbit
) and the
seventh is simply the flow rate and mass equation. This first order
system is computed by the
TimeDerivativesEquations
class.
It will be instanced by the propagator and then be modified at each step
(a fixed t value) by all the needed
force models
which
will add their contribution, the perturbing acceleration.
The integrators
provided by commons-math need the state vector at t0, the state vector first
time derivate at t0, and then calculates the next step state vector, and
ask for the next first time derivative, etc. until it reaches the final
asked date.
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