org.orekit.models.earth.ionosphere

Class KlobucharIonoModel

java.lang.Object

org.orekit.models.earth.ionosphere.KlobucharIonoModel

All Implemented Interfaces:

Serializable, IonosphericModel

public class KlobucharIonoModel
extends Object
implements IonosphericModel

Klobuchar ionospheric delay model. Klobuchar ionospheric delay model is designed as a GNSS correction model. The parameters for the model are provided by the GPS satellites in their broadcast messsage. This model is based on the assumption the electron content is concentrated in 350 km layer. The delay refers to L1 (1575.42 MHz). If the delay is sought for L2 (1227.60 MHz), multiply the result by 1.65 (Klobuchar, 1996). More generally, since ionospheric delay is inversely proportional to the square of the signal frequency f, to adapt this model to other GNSS frequencies f, multiply by (L1 / f)^2. References: ICD-GPS-200, Rev. C, (1997), pp. 125-128 Klobuchar, J.A., Ionospheric time-delay algorithm for single-frequency GPS users, IEEE Transactions on Aerospace and Electronic Systems, Vol. 23, No. 3, May 1987 Klobuchar, J.A., "Ionospheric Effects on GPS", Global Positioning System: Theory and Applications, 1996, pp.513-514, Parkinson, Spilker.

Since:

7.1

Author:

Joris Olympio

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
KlobucharIonoModel(double[] alpha, double[] beta) Create a new Klobuchar ionospheric delay model, when a single frequency system is used.
KlobucharIonoModel(double[] alpha, double[] beta, TimeScale gps) Create a new Klobuchar ionospheric delay model, when a single frequency system is used.

Method Summary

Modifier and Type	Method and Description
List<ParameterDriver>	getParametersDrivers() Get the drivers for ionospheric model parameters.
double	pathDelay(AbsoluteDate date, GeodeticPoint geo, double elevation, double azimuth, double frequency, double[] parameters) Calculates the ionospheric path delay for the signal path from a ground station to a satellite.
<T extends RealFieldElement<T>> T	pathDelay(FieldAbsoluteDate<T> date, FieldGeodeticPoint<T> geo, T elevation, T azimuth, double frequency, T[] parameters) Calculates the ionospheric path delay for the signal path from a ground station to a satellite.
<T extends RealFieldElement<T>> T	pathDelay(FieldSpacecraftState<T> state, TopocentricFrame baseFrame, double frequency, T[] parameters) Calculates the ionospheric path delay for the signal path from a ground station to a satellite.
double	pathDelay(SpacecraftState state, TopocentricFrame baseFrame, double frequency, double[] parameters) Calculates the ionospheric path delay for the signal path from a ground station to a satellite.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.models.earth.ionosphere.IonosphericModel

getParameters, getParameters

Constructor Detail

KlobucharIonoModel

@DefaultDataContext
public KlobucharIonoModel(double[] alpha,
                                              double[] beta)

Create a new Klobuchar ionospheric delay model, when a single frequency system is used. This model accounts for at least 50 percent of RMS error due to ionospheric propagation effect (ICD-GPS-200)

This constructor uses the default data context.

Parameters:

alpha - coefficients of a cubic equation representing the amplitude of the vertical delay.

beta - coefficients of a cubic equation representing the period of the model.

See Also:

KlobucharIonoModel(double[], double[], TimeScale)

KlobucharIonoModel

public KlobucharIonoModel(double[] alpha,
                          double[] beta,
                          TimeScale gps)

Create a new Klobuchar ionospheric delay model, when a single frequency system is used. This model accounts for at least 50 percent of RMS error due to ionospheric propagation effect (ICD-GPS-200)

Parameters:

alpha - coefficients of a cubic equation representing the amplitude of the vertical delay.

beta - coefficients of a cubic equation representing the period of the model.

gps - GPS time scale.

Since:

10.1

Method Detail

pathDelay

public double pathDelay(AbsoluteDate date,
                        GeodeticPoint geo,
                        double elevation,
                        double azimuth,
                        double frequency,
                        double[] parameters)

Calculates the ionospheric path delay for the signal path from a ground station to a satellite.

The path delay is computed for any elevation angle.

Parameters:

date - current date

geo - geodetic point of receiver/station

elevation - elevation of the satellite in radians

azimuth - azimuth of the satellite in radians

frequency - frequency of the signal in Hz

parameters - ionospheric model parameters

Returns:

the path delay due to the ionosphere in m

pathDelay

public double pathDelay(SpacecraftState state,
                        TopocentricFrame baseFrame,
                        double frequency,
                        double[] parameters)

Calculates the ionospheric path delay for the signal path from a ground station to a satellite.

This method is intended to be used for orbit determination issues. In that respect, if the elevation is below 0° the path delay will be equal to zero.

For individual use of the ionospheric model (i.e. not for orbit determination), another method signature can be implemented to compute the path delay for any elevation angle.

Specified by:

pathDelay in interface IonosphericModel

Parameters:

state - spacecraft state

baseFrame - base frame associated with the station

frequency - frequency of the signal in Hz

parameters - ionospheric model parameters

Returns:

the path delay due to the ionosphere in m

pathDelay

public <T extends RealFieldElement<T>> T pathDelay(FieldAbsoluteDate<T> date,
                                                   FieldGeodeticPoint<T> geo,
                                                   T elevation,
                                                   T azimuth,
                                                   double frequency,
                                                   T[] parameters)

Calculates the ionospheric path delay for the signal path from a ground station to a satellite.

The path delay is computed for any elevation angle.

Type Parameters:

T - type of the elements

Parameters:

date - current date

geo - geodetic point of receiver/station

elevation - elevation of the satellite in radians

azimuth - azimuth of the satellite in radians

frequency - frequency of the signal in Hz

parameters - ionospheric model parameters

Returns:

the path delay due to the ionosphere in m

pathDelay

public <T extends RealFieldElement<T>> T pathDelay(FieldSpacecraftState<T> state,
                                                   TopocentricFrame baseFrame,
                                                   double frequency,
                                                   T[] parameters)

Calculates the ionospheric path delay for the signal path from a ground station to a satellite.

This method is intended to be used for orbit determination issues. In that respect, if the elevation is below 0° the path delay will be equal to zero.

For individual use of the ionospheric model (i.e. not for orbit determination), another method signature can be implemented to compute the path delay for any elevation angle.

Specified by:

pathDelay in interface IonosphericModel

Type Parameters:

T - type of the elements

Parameters:

state - spacecraft state

baseFrame - base frame associated with the station

frequency - frequency of the signal in Hz

parameters - ionospheric model parameters

Returns:

the path delay due to the ionosphere in m

getParametersDrivers

public List<ParameterDriver> getParametersDrivers()

Description copied from interface: IonosphericModel

Get the drivers for ionospheric model parameters.

Specified by:

getParametersDrivers in interface IonosphericModel

Returns:

drivers for ionospheric model parameters