Description
The Integrator object is a base type that provides tolerance, max tries, force model, and fixed step properties to the objects that derive from it. See the Stepping the Spacecraft Guide for more information.
Users cannot create instances of this type of object. However, users can access instances of this object type that have been created indirectly, for example as children of other objects. Users can also access any static properties and methods on this object type.
Inheritance Hierarchy: ObjectàPropagatoràIntegrator
Derived Types: BulStoer, BulStoerVOP, Cowell, RK45, RK78, RK78VOP, RK89
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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AllowErrorViolation
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Determines whether the error tolerance may be violated once the minimum step size is reached. If this property is set to true, and the integrator step error does not meet the tolerance at 1 ms step size, the state is automatically advanced 1 ms ahead and a warning is generated.
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CalculateSTM
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Flag indicating whether or not to calculate the state transition matrix at each integration step as part of the state integration. If the PropagateCovariance flag is set to TRUE on the SpacecraftODProperties object or if the Spacecraft is in an estimation process, the STM is always calculated. If the Spacecraft.Propagator is not an Integrator type then this property is ignored.
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DeclaredName
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The name of the object as declared.
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FixedStep
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Flag denoting whether the propagator is being run in fixed-step mode (i.e. constant StepSize) or in variable-step mode (i.e. variable StepSize).
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ForceModel
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A force model.
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LargeCurvature
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Flag that signifies whether the integration has failed due to a large curvature in the force field. (1 = Integration Failed, 0 = Integration Nominal, -1 = No Integration has been performed).
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MaxTries
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The maximum number of times to attempt to change the step size in the integration process in order to meet the specified error tolerance. If the specified error tolerance is not met after MaxTries attempts, an error is thrown.
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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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StepJustTaken
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The size of the previous step taken by the integration process.
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StepsAttempted
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This represents the sum of the successful and failed steps. This property will closely reflect the performance of the integrator since it is a measure of the total number of steps executed by the integrator.
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StepsFailed
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This property is incremented once each time the integrator steps the spacecraft forward and the integrator tolerance is not met. A high ratio of the number of failed to successful steps may suggest that the integrator tolerance is too high.
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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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StepsRequested
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Represents the count of integration steps requested by the user. This property will be incremented once each time the FreeFlyer engine advances the spacecraft to a desired epoch. For the Step command, this property will be incremented once. For interval methods and Step-to commands, this property will be incremented each time bisection is performed unitl the condition is met. Abnormally high values on this property can indicate that the IntervalStopAccuracy may be too strict.
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StepsSuccessful
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This property is incremented for every successful step of the integrator. Since it may take several steps to reach the desired epoch at the specified tolerance, the number of successful steps may be greater than the number of requested steps.
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StepToTake
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The maximum possible size of the next step to take in the integration process based on the relative error tolerance. When the StepSize property is set, this property is initialized with the new StepSize value and is updated after the next step is taken.
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STM
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Returns the State Transition Matrix. The matrix is always a square where the length of each side is determined by the total number of properties being estimated or considered.
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STMCalculationMethod
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A flag indicating the method to be used to calculate the state transition matrix. Note that even if the CalculateSTM property is set to FALSE, this property still applies if the SpacecraftODProperties.PropagateCovariance flag is to TRUE or if the Spacecraft is included in an estimation process.
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Tolerance
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When the Step command is executed, intermediate integration steps are taken to ensure that the local error never exceeds this value.
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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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ResetStepStatistics
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Resets the Integrator step counters back to zero. The step counters will continue incrementing the next time the spacecraft is stepped.
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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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See also
Choosing an Integrator
Setting up an Integrator
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