Package org.orekit.estimation.measurements

Class BistaticRange

java.lang.Object

org.orekit.estimation.measurements.AbstractMeasurement<T>

org.orekit.estimation.measurements.GroundReceiverMeasurement<T>

org.orekit.estimation.measurements.BistaticRange

All Implemented Interfaces:

Comparable<ComparableMeasurement>, ComparableMeasurement, ObservedMeasurement<BistaticRange>, TimeStamped, ParameterDriversProvider

public class BistaticRange
extends GroundReceiverMeasurement<T>

Class modeling a bistatic range measurement using an emitter ground station and a receiver ground station.

The measurement is considered to be a signal:

• Emitted from the emitter ground station
• Reflected on the spacecraft
• Received on the receiver ground station

The date of the measurement corresponds to the reception on ground of the reflected signal.

The motion of the stations and the spacecraft during the signal flight time are taken into account.

Since:

11.2

Author:

Mark Rutten

Field Summary

Fields

Modifier and Type	Field	Description
static String	MEASUREMENT_TYPE	Type of the measurement.

Constructor Summary

Constructors

Constructor	Description
BistaticRange(GroundStation emitter, GroundStation receiver, AbsoluteDate date, double range, double sigma, double baseWeight, ObservableSatellite satellite)	Simple constructor.
BistaticRange(GroundStation emitter, GroundStation receiver, AbsoluteDate date, double range, double sigma, double baseWeight, SignalTravelTimeModel signalTravelTimeModel, ObservableSatellite satellite)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
protected void	fillEstimation(Gradient quantity, Map<String,Integer> paramIndices, EstimatedMeasurement<T> estimated)	Fill estimated measurements with value and derivatives.
GroundStation	getEmitterStation()	Get the emitter ground station.
protected Gradient[]	getFieldShifts(SpacecraftState[] states)	Method computing consecutive Field time shifts of participants, starting from observation date.
protected TimeStampedPVCoordinates[]	getParticipants(SpacecraftState state)	Method returning the full kinematic coordinates of signal participants at transmission dates.
TwoLegsSignalTravelTimer	getTwoLegsSignalTimer()	Getter for the two legs timer.
protected EstimatedMeasurement<BistaticRange>	theoreticalEvaluation(int iteration, int evaluation, SpacecraftState[] states)	Estimate the theoretical value.
protected EstimatedMeasurementBase<BistaticRange>	theoreticalEvaluationWithoutDerivatives(int iteration, int evaluation, SpacecraftState[] states)	Estimate the theoretical value without derivatives.

Methods inherited from class org.orekit.estimation.measurements.GroundReceiverMeasurement

computeEmissionDate, computeEmissionDateField, getCorrectedReceptionDate, getCorrectedReceptionDateField, getParameterIndices, getReceiverStation

Methods inherited from class org.orekit.estimation.measurements.AbstractMeasurement

addModifier, addParameterDriver, addParametersDrivers, estimate, estimateWithoutDerivatives, getBaseWeight, getCoordinates, getDate, getDimension, getModifiers, getObservedValue, getParametersDrivers, getSatellites, getSignalTravelTimeModel, getTheoreticalStandardDeviation, isEnabled, isTwoWay, setEnabled, setObservedValue

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.orekit.estimation.measurements.ComparableMeasurement

compareTo

Methods inherited from interface org.orekit.estimation.measurements.ObservedMeasurement

estimateWithoutDerivatives, getMeasurementType

Methods inherited from interface org.orekit.utils.ParameterDriversProvider

getNbParametersDriversValue, getParameterDriver, getParameters, getParameters, getParameters, getParameters, getParametersAllValues, getParametersAllValues, isSupported

Methods inherited from interface org.orekit.time.TimeStamped

durationFrom

Field Detail

MEASUREMENT_TYPE

public static final String MEASUREMENT_TYPE

Type of the measurement.

See Also:

Constant Field Values

Constructor Detail

BistaticRange

public BistaticRange(GroundStation emitter,
                     GroundStation receiver,
                     AbsoluteDate date,
                     double range,
                     double sigma,
                     double baseWeight,
                     ObservableSatellite satellite)

Simple constructor.

Parameters:

emitter - ground station from which transmission is performed

receiver - ground station from which measurement is performed

date - date of the measurement

range - observed value

sigma - theoretical standard deviation

baseWeight - base weight

satellite - satellite related to this measurement

Since:

11.2

BistaticRange

public BistaticRange(GroundStation emitter,
                     GroundStation receiver,
                     AbsoluteDate date,
                     double range,
                     double sigma,
                     double baseWeight,
                     SignalTravelTimeModel signalTravelTimeModel,
                     ObservableSatellite satellite)

Simple constructor.

Parameters:

emitter - ground station from which transmission is performed

receiver - ground station from which measurement is performed

date - date of the measurement

range - observed value

sigma - theoretical standard deviation

baseWeight - base weight

signalTravelTimeModel - signal travel time model

satellite - satellite related to this measurement

Since:

14.0

Method Detail

theoreticalEvaluationWithoutDerivatives

protected EstimatedMeasurementBase<BistaticRange> theoreticalEvaluationWithoutDerivatives(int iteration,
                                                                                          int evaluation,
                                                                                          SpacecraftState[] states)

Estimate the theoretical value without derivatives. The default implementation uses the computation with derivatives and ought to be overwritten for performance.

The theoretical value does not have any modifiers applied.

Overrides:

theoreticalEvaluationWithoutDerivatives in class AbstractMeasurement<BistaticRange>

Parameters:

iteration - iteration number

evaluation - evaluation number

states - orbital states at measurement date

Returns:

theoretical value

See Also:

AbstractMeasurement.estimate(int, int, SpacecraftState[])

theoreticalEvaluation

protected EstimatedMeasurement<BistaticRange> theoreticalEvaluation(int iteration,
                                                                    int evaluation,
                                                                    SpacecraftState[] states)

Estimate the theoretical value.

The theoretical value does not have any modifiers applied.

Specified by:

theoreticalEvaluation in class AbstractMeasurement<BistaticRange>

Parameters:

iteration - iteration number

evaluation - evaluation number

states - orbital states at measurement date

Returns:

theoretical value

See Also:

AbstractMeasurement.estimate(int, int, SpacecraftState[])

getTwoLegsSignalTimer

public TwoLegsSignalTravelTimer getTwoLegsSignalTimer()

Getter for the two legs timer.

Returns:

model

getEmitterStation

public GroundStation getEmitterStation()

Get the emitter ground station.

Returns:

emitter ground station

getParticipants

protected TimeStampedPVCoordinates[] getParticipants(SpacecraftState state)

Method returning the full kinematic coordinates of signal participants at transmission dates.

Parameters:

state - observable state

Returns:

signal participants

getFieldShifts

protected Gradient[] getFieldShifts(SpacecraftState[] states)

Method computing consecutive Field time shifts of participants, starting from observation date.

Parameters:

states - observables

Returns:

time shifts

fillEstimation

protected void fillEstimation(Gradient quantity,
                              Map<String,Integer> paramIndices,
                              EstimatedMeasurement<T> estimated)

Fill estimated measurements with value and derivatives.

Parameters:

quantity - estimated quantity

paramIndices - indices mapping parameter names to derivative indices

estimated - theoretical measurement class