Ephemeris Object

Description

An ephemeris is made up of data records which contain both the state (orbit) and (optionally) the orientation (attitude) of a Spacecraft at specific epochs. See FreeFlyer Ephemeris File for more information.

Inheritance Hierarchy: Object->Propagator->Ephemeris

Available In Editions:

Engineer

Mission

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.

Click here to see the documentation for this object in nanosecond timing precision mode.

Name	Description	Attributes
AutoDowngradeInterpolation	When turned on, the ephemeris will use lower-order interpolation methods when the interpolation method would require more vectors than available.	Type: Variable Access: Read/Write
CCSDSOEMProperties	A collection of properties associated with reading and writing the header of CCSDS Ephemeris Files.	Type: CCSDSOEMProperties Access: Read-Only
CentralBody	States in the ephemeris will be referenced from this central body.	Type: String Access: Read/Write
CurrentIndex	The index of the vector that corresponds to the current state of the Spacecraft that is associated with this Ephemeris.	Type: Variable Access: Read/Write
DeclaredName	The name of the object as declared.	Type: String Access: Read-Only
Duration	The duration of the ephemeris. Equal to EndEpoch - StartEpoch.	Type: Variable Access: Read-Only Units: day
EndEpoch	The epoch of the last vector in the ephemeris.	Type: Variable Access: Read-Only Units: day
FFEphemProperties	A collection of properties and methods associated with handling the header and contents of an FFEphem ephemeris file.	Type: FFEphemProperties Access: Read-Only
Filename	The filename of the Ephemeris file.	Type: String Access: Read-Only
InterpolationMethod	The interpolation method that is to be used when propagating the Spacecraft to epochs between ephemeris states.	Type: Variable Access: Read/Write
Name	The name displayed for this object in output windows such as views, plots, and reports.	Type: String Access: Read/Write
NextEpoch	The epoch of the Vector following the current vector in the ephemeris. Returns -999 if the current vector is the last Vector in the ephemeris.	Type: Variable Access: Read-Only Units: day
NumberOfVectors	The number of discrete states held within the ephemeris.	Type: Variable Access: Read-Only
ObjectId	The unique identifier for the object.	Type: Variable Access: Read-Only
ObjectType	The type of the object.	Type: String Access: Read-Only
PriorEpoch	The epoch of the Vector prior to the current vector in the ephemeris. Returns -999 if the current vector is the first Vector in the ephemeris.	Type: Variable Access: Read-Only Units: day
PropagationDirection	Determines the direction of information put to the ephemeris and the way the ephemeris putting rules are applied. Changing this property clears the ephemeris of vectors.	Type: Variable Access: Read/Write
SPKProperties	A collection of properties and methods associated with handling writing SPICE file.	Type: SPKProperties Access: Read-Only
StartEpoch	The epoch of the first vector in the ephemeris.	Type: Variable Access: Read-Only Units: day
StepSize	The time step for propagation of the spacecraft using the ephemeris. A StepSize of 0.0 means the Spacecraft will advance to the next entry in the ephemeris. Otherwise, the Spacecraft using the ephemeris will advance forwards or backwards by StepSize seconds. This property has no effect when producing an ephemeris file.	Type: Variable Access: Read/Write Units: s
WriteAcceleration	Determines whether the Spacecraft's acceleration vector will be written to the ephemeris file.	Type: Variable Access: Read/Write
WriteAngularAcceleration	Determines whether the Spacecraft's angular acceleration vector will be written to the ephemeris file.	Type: Variable Access: Read/Write
WriteAngularVelocity	Determines whether the Spacecraft's angular velocity vector will be written to the ephemeris file.	Type: Variable Access: Read/Write
WriteAttitude	Determines whether the Spacecraft's orientation will be written to the ephemeris file.	Type: Variable Access: Read/Write
WriteClockBiasAndDrift	Determines whether the Spacecraft's GPSReceiver Clock Bias and Drift will be written to the ephemeris file. This property is only used for writing to the SP3 Precise Ephemeris format.	Type: Variable Access: Read/Write
WritePositionVelocityCovariance	Determines whether the Spacecraft's 6x6 position/velocity covariance matrix will be written to the ephemeris file. This property is only used for writing to the CCSDS OEM Ephemeris format.	Type: Variable Access: Read/Write
WritePosVel	Determines whether the Spacecraft position and velocity vectors will be written to the ephemeris file.	Type: Variable Access: Read/Write

Name	Description
AddVectorData	Adds the data contained in the EphemerisVector object to the Ephemeris at the end of the existing ephemeris data.
ClearEphemeris	Clears all vectors held in memory for the ephemeris object.
ClearSavedStates	Clears previous saved states for this object.
GenerateEphemeris	Generates an Ephemeris file.
GetCovarianceData	Gets the covariance values from the ephemeris at the specified vector and returns them as a matrix.
GetFromFile	Load the object state from the specified FreeFlyer object file.
GetFromString	Load the object state from the specified string.
GetFullInterpolatedData	Populates an EphemerisVector object with data corresponding to the provided epoch.
GetFullVectorData	Populates an EphemerisVector object with data from the specified vector in the ephemeris.
GetInterpolatedVectorData	Interpolates values at the given epoch from the ephemeris at the specified columns using the interpolator selected for that column and returns the interpolated results as an array. Only works for FreeFlyer Ephemeris Version 2.0 and higher.
GetVectorData	Gets values from the ephemeris at the specified vector and returns them as an array.
LoadEphemeris	Loads an ephemeris file into the provided Ephemeris object, and returns the number of vectors loaded.
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.
SetSpacecraftState	Loads the state in the specified vector into the associated Spacecraft.
SetVectorData	Sets the values in the ephemeris at the specified vector to the supplied new data. Only works for FreeFlyer Ephemeris Version 2.0 and higher.