fr.cnes.sirius.patrius.signalpropagation.troposphere

Class SaastamoinenModel

java.lang.Object

fr.cnes.sirius.patrius.signalpropagation.troposphere.SaastamoinenModel

All Implemented Interfaces:

IParameterizable, TroposphericCorrection, Serializable

public class SaastamoinenModel
extends Object
implements TroposphericCorrection

The modified Saastamoinen model. Estimates the path delay imposed to electro-magnetic signals by the troposphere according to the formula:

 δ = 2.277e-3 / cos z * (P + (1255 / T + 0.05) * e - B * tan2
 z) + δR
 

with the following input data provided to the model:

• z: zenith angle
• P: atmospheric pressure
• T: temperature
• e: partial pressure of water vapour
• B, δR: correction terms

The model supports custom δR correction terms to be read from a configuration file (saastamoinen-correction.txt) via the DataProvidersManager.

Constants used in model are defined as such in the Saastamoinen model article.

Author:

Thomas Neidhart

See Also:

"Guochang Xu, GPS - Theory, Algorithms and Applications, Springer, 2007", Serialized Form

Constructor Summary

Constructors

Constructor and Description
SaastamoinenModel(MeteorologicalConditionsProvider meteoConditionsProvider, double altitude) Create a new Saastamoinen model for the troposphere using the given environmental conditions [T, P, RH] and station altitude.

Method Summary

Modifier and Type	Method and Description
double	calculatePathDelay(AbsoluteDate date, double elevation) Calculates the tropospheric path delay for the signal path from a ground station to a satellite at a given date.
double	computeSignalDelay(AbsoluteDate date, double elevation) Calculates the tropospheric signal delay for the signal path from a ground station to a satellite at a given date.
double	derivativeValue(Parameter p, double elevation) Compute the signal delay derivative value with respect to the input parameter.
ArrayList<Parameter>	getParameters() Get the supported parameters.
static SaastamoinenModel	getStandardModel(double altitude) Create a new Saastamoinen model using a standard atmosphere model.
boolean	isDifferentiableBy(Parameter p) Tell if the function is differentiable by the given parameter.
boolean	supportsParameter(Parameter param) Check if a parameter is supported.

Methods inherited from class java.lang.Object

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

Constructor Detail

SaastamoinenModel

public SaastamoinenModel(MeteorologicalConditionsProvider meteoConditionsProvider,
                         double altitude)

Create a new Saastamoinen model for the troposphere using the given environmental conditions [T, P, RH] and station altitude.

Parameters:

meteoConditionsProvider - provider for the meteorological conditions

altitude - the altitude above sea level of the station [m]

Method Detail

getStandardModel

public static SaastamoinenModel getStandardModel(double altitude)

Create a new Saastamoinen model using a standard atmosphere model. The standard atmosphere model uses the following reference values at mean sea level:

• reference temperature: 18 degree Celsius
• reference pressure: 101325 Pa
• reference humidity: 50%

Parameters:

altitude - the altitude above the mean sea level of the station [m]

Returns:

a Saastamoinen model with standard environmental values

supportsParameter

public boolean supportsParameter(Parameter param)

Check if a parameter is supported.

Specified by:

supportsParameter in interface IParameterizable

Parameters:

param - parameter to check

Returns:

true if the parameter is supported

getParameters

public ArrayList<Parameter> getParameters()

Get the supported parameters.

Specified by:

getParameters in interface IParameterizable

Returns:

list of supported parameters

derivativeValue

public double derivativeValue(Parameter p,
                              double elevation)

Compute the signal delay derivative value with respect to the input parameter.

Specified by:

derivativeValue in interface TroposphericCorrection

Parameters:

p - parameter

elevation - the elevation of the satellite [rad]

Returns:

the derivative value

isDifferentiableBy

public boolean isDifferentiableBy(Parameter p)

Tell if the function is differentiable by the given parameter.

Specified by:

isDifferentiableBy in interface TroposphericCorrection

Parameters:

p - function parameter

Returns:

true if the function is differentiable by the given parameter.

calculatePathDelay

public double calculatePathDelay(AbsoluteDate date,
                                 double elevation)

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

Parameters:

date - date of the meteorological conditions

elevation - the elevation of the satellite in radians

Returns:

the path delay due to the troposphere in m

computeSignalDelay

public double computeSignalDelay(AbsoluteDate date,
                                 double elevation)

Calculates the tropospheric signal delay for the signal path from a ground station to a satellite at a given date. This method exists only for convenience reasons and returns the same as

   SaastamoinenModel#calculatePathDelay(double)/
   Constants.SPEED_OF_LIGHT
 

Specified by:

computeSignalDelay in interface TroposphericCorrection

Parameters:

date - date of the meteorological conditions

elevation - the elevation of the satellite in radians

Returns:

the signal delay due to the troposphere in s