org.orekit.estimation.measurements

Class InterSatellitesRange

java.lang.Object

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

org.orekit.estimation.measurements.InterSatellitesRange

All Implemented Interfaces:

ObservedMeasurement<InterSatellitesRange>, TimeStamped

public class InterSatellitesRange
extends AbstractMeasurement<InterSatellitesRange>

One-way or two-way range measurements between two satellites.

Satellite 1 is always considered to be the satellite that receives the signal and computes the measurement.

For one-way measurements, a signal is emitted by satellite 2 and received by satellite 1. The measurement value is the elapsed time between emission and reception divided by c were c is the speed of light.

For two-way measurements, a signal is emitted by satellite 1, reflected on satellite 2, and received back by satellite 1 again. The measurement value is the elapsed time between emission and reception divided by 2c were c is the speed of light.

The motion of both satellites during the signal flight time is taken into account. The date of the measurement corresponds to the reception of the signal by satellite 1.

Since:

9.0

Author:

Luc Maisonobe

Constructor Summary

Constructors

Constructor and Description
InterSatellitesRange(int satellite1Index, int satellite2Index, boolean twoWay, AbsoluteDate date, double range, double sigma, double baseWeight) Simple constructor.

Method Summary

Modifier and Type	Method and Description
boolean	isTwoWay() Check if the instance represents a two-way measurement.
protected EstimatedMeasurement<InterSatellitesRange>	theoreticalEvaluation(int iteration, int evaluation, SpacecraftState[] states) Estimate the theoretical value.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

InterSatellitesRange

public InterSatellitesRange(int satellite1Index,
                            int satellite2Index,
                            boolean twoWay,
                            AbsoluteDate date,
                            double range,
                            double sigma,
                            double baseWeight)
                     throws OrekitException

Simple constructor.

Parameters:

satellite1Index - index of satellite 1 propagator (i.e. the satellite which receives the signal and performs the measurement)

satellite2Index - index of satellite 2 propagator (i.e. the satellite which simply emits the signal in the one-way case, or reflects the signal in the two-way case)

twoWay - flag indicating whether it is a two-way measurement

date - date of the measurement

range - observed value

sigma - theoretical standard deviation

baseWeight - base weight

Throws:

OrekitException - if a ParameterDriver name conflict occurs

Method Detail

isTwoWay

public boolean isTwoWay()

Check if the instance represents a two-way measurement.

Returns:

true if the instance represents a two-way measurement

theoreticalEvaluation

protected EstimatedMeasurement<InterSatellitesRange> theoreticalEvaluation(int iteration,
                                                                           int evaluation,
                                                                           SpacecraftState[] states)
                                                                    throws OrekitException

Estimate the theoretical value.

The theoretical value does not have any modifiers applied.

Specified by:

theoreticalEvaluation in class AbstractMeasurement<InterSatellitesRange>

Parameters:

iteration - iteration number

evaluation - evaluation number

states - orbital states at measurement date

Returns:

theoretical value

Throws:

OrekitException - if value cannot be computed

See Also:

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