KalmanFilterOD Object

Description

The KalmanFilterOD object provides algorithms for performing Orbit Determination and State Estimation using a Kalman filter technique. This allows observations to be processed sequentially, and potentially in real-time. The sequential nature of the Kalman filter provides significant power and flexibility by allowing the user to manipulate settings interactively inside the estimation process. See the Orbit Determination Guide for more information.

Inheritance Hierarchy: ObjectàODEstimationProcessàSequentialFilteràKalmanFilterOD

Derived Types: UnscentedKalmanFilterOD

Available In Editions:

Mission

Timing Precision Mode

This page describes functionality in nanosecond timing precision mode.

Name	Description
Covariance	The Covariance associated with the ODEstimationProcess.
DeclaredName	The name of the object as declared.
DisplayName	The name displayed for this object in output windows such as views, plots, and reports.
Epoch	The current epoch of the filter.
InitialFilterEpoch	The epoch to use as the initial epoch of the filter. At the first call to the filtering process, all relevant objects are synched to that initial epoch.
InitialFilterEpochDefinitionType	Specifies whether to use a Spacecraft to define the initial filter epoch, or specify it explicitly.
InitialFilterEpochSpacecraft	Spacecraft to use to define the initial epoch for the filtering process. At the first call of the filter process, all relevant objects will be synched to the epoch of this spacecraft, at the time of the execution of the Filter initialization. If no Spacecraft is specified, then the epoch of the first registered Spacecraft will be used.
LastKalmanGain	The Kalman gain matrix as computed for the last set of measurements processed. The number of rows corresponds to the number of state elements being estimated and the number of columns corresponds to the number of measurements processed. Each measurement is processed sequentially, so each column of the reported matrix is computed independently, as opposed to the more traditional Kalman gain where measurements (and columns) are processed concurrently.
MaintainHistoryOfProcessedObservations	Flag indicating whether or not to keep a buffer of observations that have been processed in the past. If this is set to TRUE, then the ProcessedObservationBufferLength property controls the amount of observations held in the buffer.
MaxAllowableSigma	The sigma tolerance to be applied when editing observation data.
MeasurementProcessingMethod	A flag indicating whether to process each Observation's measurements sequentially for multiple state updates, or simultaneously for a single state update.
MeasurementUnderweightingFactor	The fractional amount by which the measurements will be under-weighted. One represents no underweighting and the full state and covariance update. Zero represents total underweighting and no state or covariance update.
ObjectId	The unique identifier for the object.
ObjectsToProcess	Array of objects that have been included in the Orbit Determination process.
ObjectType	The type of the object.
ObservationEditingBehavior	A flag indicating whether to edit tracking data at a per measurement level, or if any measurement of an observation is bad edit the whole observation. Note, this is only used when measurements are processed simultaneously, as specified by the MeasurementProcessingMethod property.
ProcessedObservationBufferLength	The number of Observations to hold in the buffer. If this number is equal to -1, then ALL observations will be kept in the buffer.
ProcessedObservations	An array of Observations that have been processed by the KalmanFilterOD object.
RegisteredTrackingDataFiles	Array of TrackingDataFile objects used to provided observations for the ODEstimationProcess.
Smoother	The Smoother associated with the the KalmanFilterOD object.
StepSize	The maximum step size used when propagating the Covariance.
ThrustEventsToModel	Array of Maneuver objects to be modeled as part of the propagation for the orbit determination process.
UseMeasurementUnderweighting	A flag indicating whether or not to use the measurement underweighting equations as part of the filter state and covariance update.
UseSmoother	A flag indicating whether or not to use the Smoother.

Name	Description
AddObjectToProcess	Include the object in the Estimation process. Whether the object properties are Estimated, Considered, or Ignored is determined by the object's ProcessAction flags.
AddThrustEventToSequence	Adds a ThrustEvent to the OD Estimation sequence, and associates it with a spacecraft to which the thrust event will be applied.
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.
GetNextObservationEpoch	Get the epoch of the next Observation in the buffer associated with the Orbit Determination process.
GetPostUpdateResidualStatistics	Computes statistics on the list of Observations which are in the Observation Buffer. Returns the number of measurement types included in the Observation buffer.
GetPreUpdateResidualStatistics	Computes statistics on the list of Observations which are in the Observation Buffer. Returns the number of measurement types included in the Observation buffer.
GetProcessingStatus	Computes the total number of measurements that were Accepted, Rejected, or Not Processed for the list of Observations which are in the Observation Buffer. Returns the number of measurement types included in the Observation buffer.
GetPropertiesInStateVector	Gets the list of properties included in the state vector for the ODEstimation object.
NumberOfObservationsAtCurrentEpoch	Returns the number of observations at the current filter epoch, which have not been processed yet. Note when processing pseudorange data, multiple observations can be processed at one time for the same epoch.
ProcessNextObservation	Process the next Observation in the buffer associated with the Orbit Determination process.
ProcessObservation	Process the Observation with the Orbit Determination process. The Measurements processed will be determined by the Usage and Validity flags.
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.
RegisterOrbitStateObservationGenerator	Register the specified trajectory observation generator with the OD estimator process.
RegisterTrackingDataFile	Register the specified tracking data file with the OD estimator process.
Reset	Reset the estimation process, closing out all associated tracking data files, and clearing out any observation buffers.
Restore	Restore an object's state from a previously saved state.
Save	Save the object's state so that it can be restored later.
SetAprioriCovariance	Sets the apriori covariance matrix for the estimation process. This must be called prior to starting the estimation process, and must match the dimension of the state vector.
SetAprioriSquareRootInformation	Sets the apriori square root information matrix for the estimation process. This must be called prior to starting the estimation process, and must match the dimension of the state vector.
SetInitialFilterEpochFromSpacecraft	Defines the Spacecraft to use for obtaining the initial epoch of the filter. This epoch is evaluated at the first execution of a filter operation.
StepOD	Step all the objects associated with the Orbit Determination process by the StepSize of the filter.
StepToEpoch	Steps all of the objects associated with the Orbit Determination process to the specified epoch.
StepToNextObservation	Step all the objects associated with the Orbit Determination process to the epoch of the next Observation in the buffer. If no more Observations are found, this method returns 0.