Package org.orekit.estimation.measurements

Class BistaticRangeRate

java.lang.Object

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

org.orekit.estimation.measurements.SignalBasedMeasurement<BistaticRangeRate>

org.orekit.estimation.measurements.BistaticRangeRate

All Implemented Interfaces:

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

public class BistaticRangeRate
extends SignalBasedMeasurement<BistaticRangeRate>

Class modeling a bistatic range rate 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 quantity measured at the receiver is the bistatic radial velocity as the sum of the radial velocities with respect to the two stations.

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

The Doppler measurement can be obtained by multiplying the velocity by (fe/c), where fe is the emission frequency.

Since:

11.2

Author:

Pascal Parraud

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor	Description
BistaticRangeRate(Observer emitter, Observer receiver, AbsoluteDate date, double rangeRate, double sigma, double baseWeight, ObservableSatellite satellite)	Simple constructor.
BistaticRangeRate(Observer emitter, Observer receiver, AbsoluteDate date, double rangeRate, MeasurementQuality measurementQuality, SignalTravelTimeModel signalTravelTimeModel, ObservableSatellite satellite)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
protected void	fillEstimation(Gradient quantity, Map<String,Integer> paramIndices, EstimatedMeasurement<BistaticRangeRate> estimated)	Fill estimated measurements with value and derivatives.
Observer	getEmitter()	Get the emitter object.
GroundStation	getEmitterStation()	Deprecated. as of 14.0, replaced by getEmitter()
protected Gradient[]	getFieldShifts(SpacecraftState[] states)	Method computing consecutive Field time shifts of participants, starting from observation date.
protected TimeStampedPVCoordinates[]	getParticipants(SpacecraftState state, PVCoordinatesProvider emitterPVProvider, PVCoordinatesProvider receiverPVProvider)	Method returning the full kinematic coordinates of signal participants at transmission dates.
Observer	getReceiver()	Get the receiver object.
GroundStation	getReceiverStation()	Deprecated. as of 14.0, replaced by getReceiver()
TwoLeggedSignalTimer	getTwoLeggedSignalTimer()	Getter for the two legs timer.
protected EstimatedMeasurement<BistaticRangeRate>	theoreticalEvaluation(int iteration, int evaluation, SpacecraftState[] states)	Estimate the theoretical value.
protected EstimatedMeasurementBase<BistaticRangeRate>	theoreticalEvaluationWithoutDerivatives(int iteration, int evaluation, SpacecraftState[] states)	Estimate the theoretical value without derivatives.

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

getSignalTravelTimeModel, isTwoWay

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

addModifier, addParameterDriver, addParametersDrivers, estimate, estimateWithoutDerivatives, getCoordinates, getDate, getMeasurementQuality, getModifiers, getObservedValue, getParameterIndices, getParametersDrivers, getSatellites, isEnabled, 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, getBaseWeight, getDimension, getMeasurementType, getTheoreticalStandardDeviation

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 Details

MEASUREMENT_TYPE

public static final String MEASUREMENT_TYPE

Type of the measurement.

See Also:

• Constant Field Values

Constructor Details

BistaticRangeRate

public BistaticRangeRate(Observer emitter,
 Observer receiver,
 AbsoluteDate date,
 double rangeRate,
 double sigma,
 double baseWeight,
 ObservableSatellite satellite)

Simple constructor.

Parameters:

emitter - emitter object

receiver - receiver object

date - date of the measurement

rangeRate - observed value, m/s

sigma - theoretical standard deviation

baseWeight - base weight

satellite - satellite related to this measurement

BistaticRangeRate

public BistaticRangeRate(Observer emitter,
 Observer receiver,
 AbsoluteDate date,
 double rangeRate,
 MeasurementQuality measurementQuality,
 SignalTravelTimeModel signalTravelTimeModel,
 ObservableSatellite satellite)

Simple constructor.

Parameters:

emitter - emitter object

receiver - receiver object

date - date of the measurement

rangeRate - observed value, m/s

measurementQuality - measurement quality data as used in orbit determination

signalTravelTimeModel - signal travel time model

satellite - satellite related to this measurement

Since:

14.0

Method Details

theoreticalEvaluationWithoutDerivatives

protected EstimatedMeasurementBase<BistaticRangeRate> 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<BistaticRangeRate>

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<BistaticRangeRate> 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<BistaticRangeRate>

Parameters:

iteration - iteration number

evaluation - evaluation number

states - orbital states at measurement date

Returns:

theoretical value

See Also:

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

getTwoLeggedSignalTimer

public TwoLeggedSignalTimer getTwoLeggedSignalTimer()

Getter for the two legs timer.

Returns:

model

getEmitterStation

@Deprecated
public GroundStation getEmitterStation()

Deprecated.

as of 14.0, replaced by getEmitter()

Get the emitter ground station.

Returns:

emitter ground station

getEmitter

public Observer getEmitter()

Get the emitter object.

Returns:

emitter object

Since:

14.0

getReceiverStation

@Deprecated
public GroundStation getReceiverStation()

Deprecated.

as of 14.0, replaced by getReceiver()

Get the receiver ground station.

Returns:

receiver ground station

getReceiver

public Observer getReceiver()

Get the receiver object.

Returns:

receiver object

Since:

14.0

getParticipants

protected TimeStampedPVCoordinates[] getParticipants(SpacecraftState state,
 PVCoordinatesProvider emitterPVProvider,
 PVCoordinatesProvider receiverPVProvider)

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

Parameters:

state - observable state

emitterPVProvider - emitter coordinates provider

receiverPVProvider - receiver coordinates provider

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<BistaticRangeRate> estimated)

Fill estimated measurements with value and derivatives.

Parameters:

quantity - estimated quantity

paramIndices - indices mapping parameter names to derivative indices

estimated - theoretical measurement class