org.orekit.estimation.measurements

Class TDOA

java.lang.Object

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

org.orekit.estimation.measurements.TDOA

All Implemented Interfaces:

Comparable<ComparableMeasurement>, ComparableMeasurement, ObservedMeasurement<TDOA>, TimeStamped

public class TDOA
extends AbstractMeasurement<TDOA>

Class modeling a Time Difference of Arrival measurement with a satellite as emitter and two ground stations as receivers.

TDOA measures the difference in signal arrival time between the emitter and receivers, corresponding to a difference in ranges from the two receivers to the emitter.

The date of the measurement corresponds to the reception of the signal by the prime station. The measurement corresponds to the date of the measurement minus the date of reception of the signal by the second station: tdoa = tr1 - tr2

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

Since:

11.2

Author:

Pascal Parraud

Constructor Summary

Constructors

Constructor and Description
TDOA(GroundStation primeStation, GroundStation secondStation, AbsoluteDate date, double tdoa, double sigma, double baseWeight, ObservableSatellite satellite) Simple constructor.

Method Summary

Modifier and Type	Method and Description
GroundStation	getPrimeStation() Get the prime ground station, the one that gives the date of the measurement.
GroundStation	getSecondStation() Get the second ground station, the one that gives the measurement.
protected EstimatedMeasurement<TDOA>	theoreticalEvaluation(int iteration, int evaluation, SpacecraftState[] states) Estimate the theoretical value.

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

addModifier, addParameterDriver, estimate, getBaseWeight, getCoordinates, getDate, getDimension, getModifiers, getObservedValue, getParametersDrivers, getSatellites, getTheoreticalStandardDeviation, isEnabled, setEnabled, signalTimeOfFlight, signalTimeOfFlight

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

Constructor Detail

TDOA

public TDOA(GroundStation primeStation,
            GroundStation secondStation,
            AbsoluteDate date,
            double tdoa,
            double sigma,
            double baseWeight,
            ObservableSatellite satellite)

Simple constructor.

Parameters:

primeStation - ground station that gives the date of the measurement

secondStation - ground station that gives the measurement

date - date of the measurement

tdoa - observed value (s)

sigma - theoretical standard deviation

baseWeight - base weight

satellite - satellite related to this measurement

Method Detail

getPrimeStation

public GroundStation getPrimeStation()

Get the prime ground station, the one that gives the date of the measurement.

Returns:

prime ground station

getSecondStation

public GroundStation getSecondStation()

Get the second ground station, the one that gives the measurement.

Returns:

second ground station

theoreticalEvaluation

protected EstimatedMeasurement<TDOA> 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<TDOA>

Parameters:

iteration - iteration number

evaluation - evaluation number

states - orbital states at measurement date

Returns:

theoretical value

See Also:

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