SemiAnalyticalUnscentedKalmanEstimator (OREKIT 12.1.2 API)

java.lang.Object
- org.orekit.estimation.sequential.AbstractKalmanEstimator
- - org.orekit.estimation.sequential.SemiAnalyticalUnscentedKalmanEstimator

```
public class SemiAnalyticalUnscentedKalmanEstimator
extends AbstractKalmanEstimator
```
Implementation of an Unscented Semi-analytical Kalman filter (USKF) to perform orbit determination.
The filter uses a DSSTPropagatorBuilder.

The estimated parameters are driven by ParameterDriver objects. They are of 3 different types:
1. Orbital parameters:The position and velocity of the spacecraft, or, more generally, its orbit.
  These parameters are retrieved from the reference trajectory propagator builder when the filter is initialized.
2. Propagation parameters: Some parameters modeling physical processes (SRP or drag coefficients etc...).
  They are also retrieved from the propagator builder during the initialization phase.
3. Measurements parameters: Parameters related to measurements (station biases, positions etc...).
  They are passed down to the filter in its constructor.
The Kalman filter implementation used is provided by the underlying mathematical library Hipparchus. All the variables seen by Hipparchus (states, covariances...) are normalized using a specific scale for each estimated parameters or standard deviation noise for each measurement components.

An SemiAnalyticalUnscentedKalmanEstimator object is built using the build method of a SemiAnalyticalUnscentedKalmanEstimatorBuilder.
Since:

11.3

Author:

Gaëtan Pierre, Bryan Cazabonne

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected KalmanEstimation`	`getKalmanEstimation()`	Get the provider for kalman filter estimations.
`DSSTPropagator`	`processMeasurements(List<ObservedMeasurement<?>> observedMeasurements)`	Process a single measurement.
`void`	`setObserver(KalmanObserver observer)`	Set the observer.

Methods inherited from class org.orekit.estimation.sequential.AbstractKalmanEstimator
getCurrentDate, getCurrentMeasurementNumber, getEstimatedMeasurementsParameters, getOrbitalParametersDrivers, getPhysicalEstimatedCovarianceMatrix, getPhysicalEstimatedState, getPropagationParametersDrivers

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getKalmanEstimation
```
protected KalmanEstimation getKalmanEstimation()
```
    Get the provider for kalman filter estimations..
    
    Specified by:
    
    getKalmanEstimation in class AbstractKalmanEstimator
    
    Returns:
    
    the provider for Kalman filter estimations
  - setObserver
```
public void setObserver(KalmanObserver observer)
```
    Set the observer.
    
    Parameters:
    
    observer - the observer
  - processMeasurements
```
public DSSTPropagator processMeasurements(List<ObservedMeasurement<?>> observedMeasurements)
```
    Process a single measurement.
    Update the filter with the new measurement by calling the estimate method.
    
    Parameters:
    
    observedMeasurements - the list of measurements to process
    
    Returns:
    
    estimated propagators