org.orekit.models.earth.troposphere

Class EstimatedTroposphericModel

java.lang.Object

org.orekit.models.earth.troposphere.EstimatedTroposphericModel

All Implemented Interfaces:

DiscreteTroposphericModel, MappingFunction

public class EstimatedTroposphericModel
extends Object
implements DiscreteTroposphericModel

An estimated tropospheric model. The tropospheric delay is computed according to the formula:

δ = δ_h * m_h + (δ_t - δ_h) * m_w

With:

• δ_h: Tropospheric zenith hydro-static delay.
• δ_t: Tropospheric total zenith delay.
• m_h: Hydro-static mapping function.
• m_w: Wet mapping function.

The mapping functions m_h(e) and m_w(e) are computed thanks to a model initialized by the user. The user has the possiblility to use several mapping function models for the computations: the Global Mapping Function, or the Niell Mapping Function

The tropospheric zenith delay δ_h is computed empirically with a SaastamoinenModel while the tropospheric total zenith delay δ_t is estimated as a ParameterDriver

Field Summary

Fields

Modifier and Type	Field and Description
static String	TOTAL_ZENITH_DELAY Name of the parameter of this model: the total zenith delay.

Constructor Summary

Constructors

Constructor and Description
EstimatedTroposphericModel(double t0, double p0, MappingFunction model, double totalDelay) Build a new instance using the given environmental conditions.
EstimatedTroposphericModel(MappingFunction model, double totalDelay) Build a new instance using a standard atmosphere model.

Method Summary

Modifier and Type	Method and Description
double[]	computeZenithDelay(double height, double[] parameters, AbsoluteDate date) This method allows the computation of the zenith hydrostatic and zenith total delays.
<T extends RealFieldElement<T>> T[]	computeZenithDelay(T height, T[] parameters, FieldAbsoluteDate<T> date) This method allows the computation of the zenith hydrostatic and zenith total delays.
List<ParameterDriver>	getParametersDrivers() Get the drivers for tropospheric model parameters.
double[]	mappingFactors(double elevation, double height, double[] parameters, AbsoluteDate date) This method allows the computation of the hydrostatic and wet mapping functions.
<T extends RealFieldElement<T>> T[]	mappingFactors(T elevation, T height, T[] parameters, FieldAbsoluteDate<T> date) This method allows the computation of the hydrostatic and wet mapping functions.
double	pathDelay(double elevation, double height, double[] parameters, AbsoluteDate date) Calculates the tropospheric path delay for the signal path from a ground station to a satellite.
<T extends RealFieldElement<T>> T	pathDelay(T elevation, T height, T[] parameters, FieldAbsoluteDate<T> date) Calculates the tropospheric 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.troposphere.MappingFunction

getParameters, getParameters

Field Detail

TOTAL_ZENITH_DELAY

public static final String TOTAL_ZENITH_DELAY

Name of the parameter of this model: the total zenith delay.

See Also:

Constant Field Values

Constructor Detail

EstimatedTroposphericModel

public EstimatedTroposphericModel(double t0,
                                  double p0,
                                  MappingFunction model,
                                  double totalDelay)

Build a new instance using the given environmental conditions.

Parameters:

t0 - the temperature at the station [K]

p0 - the atmospheric pressure at the station [mbar]

model - mapping function model (NMF or GMF).

totalDelay - initial value for the tropospheric zenith total delay [m]

EstimatedTroposphericModel

public EstimatedTroposphericModel(MappingFunction model,
                                  double totalDelay)

Build a new instance using a standard atmosphere model.

• temperature: 18 degree Celsius
• pressure: 1013.25 mbar

Parameters:

model - mapping function model (NMF or GMF).

totalDelay - initial value for the tropospheric zenith total delay [m]

Method Detail

mappingFactors

public double[] mappingFactors(double elevation,
                               double height,
                               double[] parameters,
                               AbsoluteDate date)

Description copied from interface: MappingFunction

This method allows the computation of the hydrostatic and wet mapping functions. The resulting element is an array having the following form:

• double[0] = m_h(e) → hydrostatic mapping function
• double[1] = m_w(e) → wet mapping function

Specified by:

mappingFactors in interface MappingFunction

Parameters:

elevation - the elevation of the satellite, in radians.

height - the height of the station in m above sea level.

parameters - tropospheric model parameters.

date - current date

Returns:

a two components array containing the hydrostatic and wet mapping functions.

mappingFactors

public <T extends RealFieldElement<T>> T[] mappingFactors(T elevation,
                                                          T height,
                                                          T[] parameters,
                                                          FieldAbsoluteDate<T> date)

Description copied from interface: MappingFunction

This method allows the computation of the hydrostatic and wet mapping functions. The resulting element is an array having the following form:

• T[0] = m_h(e) → hydrostatic mapping function
• T[1] = m_w(e) → wet mapping function

Specified by:

mappingFactors in interface MappingFunction

Type Parameters:

T - type of the elements

Parameters:

elevation - the elevation of the satellite, in radians.

height - the height of the station in m above sea level.

parameters - tropospheric model parameters.

date - current date

Returns:

a two components array containing the hydrostatic and wet mapping functions.

getParametersDrivers

public List<ParameterDriver> getParametersDrivers()

Description copied from interface: MappingFunction

Get the drivers for tropospheric model parameters.

Specified by:

getParametersDrivers in interface MappingFunction

Returns:

drivers for tropospheric model parameters

pathDelay

public double pathDelay(double elevation,
                        double height,
                        double[] parameters,
                        AbsoluteDate date)

Description copied from interface: DiscreteTroposphericModel

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

Specified by:

pathDelay in interface DiscreteTroposphericModel

Parameters:

elevation - the elevation of the satellite, in radians

height - the height of the station in m above sea level

parameters - tropospheric model parameters.

date - current date

Returns:

the path delay due to the troposphere in m

pathDelay

public <T extends RealFieldElement<T>> T pathDelay(T elevation,
                                                   T height,
                                                   T[] parameters,
                                                   FieldAbsoluteDate<T> date)

Description copied from interface: DiscreteTroposphericModel

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

Specified by:

pathDelay in interface DiscreteTroposphericModel

Type Parameters:

T - type of the elements

Parameters:

elevation - the elevation of the satellite, in radians

height - the height of the station in m above sea level

parameters - tropospheric model parameters.

date - current date

Returns:

the path delay due to the troposphere in m

computeZenithDelay

public double[] computeZenithDelay(double height,
                                   double[] parameters,
                                   AbsoluteDate date)

This method allows the computation of the zenith hydrostatic and zenith total delays. The resulting element is an array having the following form:

• double[0] = D_hz → zenith hydrostatic delay
• double[1] = D_tz → zenith total delay

The user have to be careful because the others tropospheric models in Orekit compute the zenith wet delay instead of the total zenith delay.

Specified by:

computeZenithDelay in interface DiscreteTroposphericModel

Parameters:

height - the height of the station in m above sea level.

parameters - tropospheric model parameters.

date - current date

Returns:

a two components array containing the zenith hydrostatic and wet delays.

computeZenithDelay

public <T extends RealFieldElement<T>> T[] computeZenithDelay(T height,
                                                              T[] parameters,
                                                              FieldAbsoluteDate<T> date)

This method allows the computation of the zenith hydrostatic and zenith total delays. The resulting element is an array having the following form:

• double[0] = D_hz → zenith hydrostatic delay
• double[1] = D_tz → zenith total delay

The user have to be careful because the others tropospheric models in Orekit compute the zenith wet delay instead of the total zenith delay.

Specified by:

computeZenithDelay in interface DiscreteTroposphericModel

Type Parameters:

T - type of the elements

Parameters:

height - the height of the station in m above sea level.

parameters - tropospheric model parameters.

date - current date

Returns:

a two components array containing the zenith hydrostatic and wet delays.