HCW Object

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.

Available In Editions:

Timing Precision Mode

This page describes functionality in millisecond timing precision mode. Millisecond timing precision mode is deprecated and will be removed in a future release. We recommend that you migrate your Mission Plans to nanosecond timing precision mode.

Signatures	Description
HCW()	Creates a default HCW object.

Name	Description	Attributes
CoordinateSetToPropagate	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.	Type: Variable Access: Read/Write
CurrentReferenceOrbit	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)	Type: Array Access: Read-Only
DeclaredName	The name of the object as declared.	Type: String Access: Read-Only
InitialReferenceEpoch	The epoch associated with the InitialReferenceOrbit.	Type: Variable Access: Read-Only Units: day
InitialReferenceOrbit	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 ICRF. 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.	Type: Array Access: Read-Only
Name	The name displayed for this object in output windows such as views, plots, and reports.	Type: String Access: Read/Write
ObjectId	The unique identifier for the object.	Type: Variable Access: Read-Only
ObjectType	The type of the object.	Type: String Access: Read-Only
StepSize	The number of seconds the propagated object is advanced when the Step command is executed.	Type: Variable Access: Read/Write Units: s

Name	Description
ClearSavedStates	Clears previous saved states for this object.
GetFromFile	Load the object state from the specified FreeFlyer object file.
GetFromString	Load the object state from the specified string.
PutToFile	Convert the object state to FreeFlyer object xml and write to a file.
PutToString	Convert the object state to FreeFlyer object xml and return as a string.
ReferenceEquals	Returns 1 if the argument refers to the calling object and 0 otherwise.
Restore	Restore an object's state from a previously saved state.
Save	Save the object's state so that it can be restored later.
SetReferenceOrbit	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.

HCW Object

Description

Available In Editions:

Timing Precision Mode