Package org.orekit.models.earth.ionosphere

Class KlobucharIonoModel

java.lang.Object
org.orekit.models.earth.ionosphere.AbstractIonosphericModel
org.orekit.models.earth.ionosphere.KlobucharIonoModel
All Implemented Interfaces:
IonosphericModel, ParameterDriversProvider
public class KlobucharIonoModel extends AbstractIonosphericModel
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

  • Constructor Details

    • KlobucharIonoModel

      @DefaultDataContext public KlobucharIonoModel(OneAxisEllipsoid earth, 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:
      earth - earth body shape
      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

      public KlobucharIonoModel(OneAxisEllipsoid earth, 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:
      earth - earth body shape
      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:
      14.0

  • Method Details

    • 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(Vector3D localP1, Vector3D localP2, TopocentricFrame baseFrame, AbsoluteDate receptionDate, double frequency, double[] parameters)
      Calculates the ionospheric path delay for the signal path from a ground station to an observing object (ground station or 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.

      Parameters:
      localP1 - position of path start point in baseFrame
      localP2 - position of path end point in baseFrame
      baseFrame - topocentric frame of point with lowest altitude between p1 and p2
      receptionDate - date at signal reception
      frequency - frequency of the signal in Hz
      parameters - ionospheric model parameters at state date
      Returns:
      the path delay due to the ionosphere in m

    • pathDelay

      public <T extends CalculusFieldElement<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 CalculusFieldElement<T>> T pathDelay(FieldVector3D<T> localP1, FieldVector3D<T> localP2, TopocentricFrame baseFrame, FieldAbsoluteDate<T> receptionDate, double frequency, T[] parameters)
      Calculates the ionospheric path delay for the signal path from a ground station to an observing object (ground station or 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.

      Type Parameters:
      T - type of the elements
      Parameters:
      localP1 - position of path start point in baseFrame
      localP2 - position of path end point in baseFrame
      baseFrame - topocentric frame of point with lowest altitude between p1 and p2
      receptionDate - date at signal reception
      frequency - frequency of the signal in Hz
      parameters - ionospheric model parameters at state date
      Returns:
      the path delay due to the ionosphere in m

    • getParametersDrivers

      public List<ParameterDriver> getParametersDrivers()
      Description copied from interface: ParameterDriversProvider
      Get the drivers for parameters.
      Returns:
      drivers for parameters