org.orekit.models.earth

Class KlobucharIonoModel

java.lang.Object

org.orekit.models.earth.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 single L1 frequency system is used.
KlobucharIonoModel(double[] alpha, double[] beta, double frequency) Create a new Klobuchar ionospheric delay model, when a single frequency system is used.

Method Summary

Modifier and Type	Method and Description
double	pathDelay(AbsoluteDate date, GeodeticPoint geo, double elevation, double azimuth) 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

Constructor Detail

KlobucharIonoModel

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

Create a new Klobuchar ionospheric delay model, when single L1 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.

KlobucharIonoModel

public KlobucharIonoModel(double[] alpha,
                          double[] beta,
                          double frequency)

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.

frequency - frequency of the radiowave signal in MHz

Method Detail

pathDelay

public double pathDelay(AbsoluteDate date,
                        GeodeticPoint geo,
                        double elevation,
                        double azimuth)

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

Specified by:

pathDelay in interface IonosphericModel

Parameters:

date - current date

geo - the Geodetic point of receiver/station

elevation - the elevation of the satellite

azimuth - the azimuth of the satellite

Returns:

the path delay due to the ionosphere in m