Package org.orekit.estimation.measurements.signal

Class SignalTravelTimeAdjustableEmitter

java.lang.Object

org.orekit.estimation.measurements.signal.SignalTravelTimeAdjustableEmitter

public class SignalTravelTimeAdjustableEmitter
extends Object

Class for computing signal time of travel with an adjustable emitter and a fixed receiver's position and date. The delay is calculated via a fixed-point algorithm with customizable settings (even enabling instantaneous transmission).

Since:

14.0

Author:

Romain Serra

Field Summary

Fields

Modifier and Type	Field	Description
protected static double	C_RECIPROCAL	Reciprocal for light speed.
protected static int	DEFAULT_MAX_ITER	Maximum number of iterations.

Constructor Summary

Constructors

Constructor	Description
SignalTravelTimeAdjustableEmitter(PVCoordinatesProvider adjustableEmitterPVProvider)	Constructor with default iteration settings.
SignalTravelTimeAdjustableEmitter(PVCoordinatesProvider adjustableEmitterPVProvider, ConvergenceChecker<Double> checker)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected double	compute(PVCoordinatesProvider pvCoordinatesProvider, double initialOffset, Vector3D fixedPosition, AbsoluteDate guessDate, Frame frame)	Compute propagation delay on a link leg (typically downlink or uplink).
double	computeDelay(Vector3D receiverPosition, AbsoluteDate signalArrivalDate, Frame frame)	Compute propagation delay on a link leg (typically downlink or uplink) without custom guess.
double	computeDelay(AbsoluteDate approxEmissionDate, Vector3D receiverPosition, AbsoluteDate signalArrivalDate, Frame frame)	Compute propagation delay on a link leg (typically downlink or uplink).
protected double	computeShift(double offset, double delay)	Computes the time shift.
ConvergenceChecker<Double>	getConvergenceChecker()	Getter for the convergence checker.
static SignalTravelTimeAdjustableEmitter	of(SpacecraftState state)	Build instance from spacecraft state.

Methods inherited from class java.lang.Object

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

Field Detail

C_RECIPROCAL

protected static final double C_RECIPROCAL

Reciprocal for light speed.

See Also:

Constant Field Values

DEFAULT_MAX_ITER

protected static final int DEFAULT_MAX_ITER

Maximum number of iterations.

See Also:

Constant Field Values

Constructor Detail

SignalTravelTimeAdjustableEmitter

public SignalTravelTimeAdjustableEmitter(PVCoordinatesProvider adjustableEmitterPVProvider)

Constructor with default iteration settings.

Parameters:

adjustableEmitterPVProvider - adjustable emitter

SignalTravelTimeAdjustableEmitter

public SignalTravelTimeAdjustableEmitter(PVCoordinatesProvider adjustableEmitterPVProvider,
                                         ConvergenceChecker<Double> checker)

Constructor.

Parameters:

adjustableEmitterPVProvider - adjustable emitter

checker - convergence checker for fixed-point algorithm

Method Detail

of

public static SignalTravelTimeAdjustableEmitter of(SpacecraftState state)

Build instance from spacecraft state.

Parameters:

state - spacecraft state

Returns:

signal travel time computer

computeDelay

public double computeDelay(Vector3D receiverPosition,
                           AbsoluteDate signalArrivalDate,
                           Frame frame)

Compute propagation delay on a link leg (typically downlink or uplink) without custom guess.

Parameters:

receiverPosition - fixed position of receiver at signalArrivalDate

signalArrivalDate - date at which the signal arrives to receiver

frame - Inertial frame in which receiver is defined.

Returns:

positive delay between signal emission and signal reception dates

computeDelay

public double computeDelay(AbsoluteDate approxEmissionDate,
                           Vector3D receiverPosition,
                           AbsoluteDate signalArrivalDate,
                           Frame frame)

Compute propagation delay on a link leg (typically downlink or uplink).

Parameters:

approxEmissionDate - approximate emission date

receiverPosition - fixed position of receiver at signalArrivalDate

signalArrivalDate - date at which the signal arrives to receiver

frame - Inertial frame in which receiver is defined.

Returns:

positive delay between signal emission and signal reception dates

computeShift

protected double computeShift(double offset,
                              double delay)

Computes the time shift.

Parameters:

offset - time offset

delay - time delay

Returns:

time shift to use in computation

getConvergenceChecker

public ConvergenceChecker<Double> getConvergenceChecker()

Getter for the convergence checker.

Returns:

checker

compute

protected double compute(PVCoordinatesProvider pvCoordinatesProvider,
                         double initialOffset,
                         Vector3D fixedPosition,
                         AbsoluteDate guessDate,
                         Frame frame)

Compute propagation delay on a link leg (typically downlink or uplink). The max. iteration number and convergence checker can be tweaked to emulate no-delay a.k.a. instantaneous transmission.

Parameters:

pvCoordinatesProvider - adjustable emitter/receiver

initialOffset - guess for the time off set

fixedPosition - fixed receiver/emitter position

guessDate - guess for emission/reception date

frame - Inertial frame in which receiver/emitter is defined.

Returns:

positive delay between signal emission and signal reception dates