Description
The HCW propagator is a propagator that uses the HCW equations of motion to propagate a Spacecraft object forward in time. HCW propagation is always referenced against a specified Cartesian or curvilinear coordinate set and additionally requires an initial orbit reference from which to begin the HCW formulation.
Inheritance Hierarchy: ObjectàPropagatoràHCW
Available In Editions:
Engineer
Mission
Timing Precision Mode
This page describes functionality in millisecond timing precision mode.
Name
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Description
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CoordinateSetToPropagate
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The coordinate set used when propagating the HCW equations of motion. Propagating in Cartesian coordinates is the classical HCW formulation. RIC Cylindrical or RIC Spherical relative elements can also be propagated using the same HCW equations, which can achieve more accurate results.
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CurrentReferenceOrbit
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The Keplerian state of the HCW propagator's InitialReferenceOrbit when propagated using a two body (Keplerian) propagator from the InitialReferenceOrbitEpoch to the Spacecraft's current epoch. The reference orbit is specified in Keplerian elements (A, E, I, RAAN, W, TA)
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DeclaredName
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The name of the object as declared.
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InitialReferenceEpoch
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The epoch associated with the InitialReferenceOrbit.
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InitialReferenceOrbit
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The reference orbit is the orbit of the "primary" or "chief" satellite used when propagating the Spacecraft using the HCW (Hills-Clohessy-Wiltshire) equations of relative motion. The reference orbit is specified in Keplerian elements (A, E, I, RAAN, W, TA) with respect to the MJ2000 Earth Equator frame. This is set using the SetReferenceOrbit() method. The reference orbit will be propagated with a two body (Keplerian) propagator when the Spacecraft is stepped. The initial reference orbit state corresponds to the InitialReferenceOrbitEpoch property. The updated reference orbit corresponding to the Spacecraft object's current epoch can be queried using CurrentReferenceOrbit.
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Name
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The name displayed for this object in output windows such as views, plots, and reports.
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ObjectId
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The unique identifier for the object.
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ObjectType
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The type of the object.
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StepSize
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The number of seconds the propagated object is advanced when the Step command is executed.
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Name
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Description
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ClearSavedStates
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Clears previous saved states for this object.
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GetFromFile
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Load the object state from the specified FreeFlyer object file.
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GetFromString
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Load the object state from the specified string.
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PutToFile
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Convert the object state to FreeFlyer object xml and write to a file.
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PutToString
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Convert the object state to FreeFlyer object xml and return as a string.
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ReferenceEquals
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Returns 1 if the argument refers to the calling object and 0 otherwise.
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Restore
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Restore an object's state from a previously saved state.
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Save
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Save the object's state so that it can be restored later.
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SetReferenceOrbit
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Sets the reference orbit of the calling HCW propagator. The reference orbit will be propagated with a two body (Keplerian) propagator when this Spacecraft is stepped.
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See also
Relative Motion Guide
HCW Propagation Guide
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