org.orekit.models.earth

Class SaastamoinenModel

java.lang.Object

org.orekit.models.earth.SaastamoinenModel

All Implemented Interfaces:

Serializable, TroposphericDelayModel

public class SaastamoinenModel
extends Object
implements TroposphericDelayModel

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.

Author:

Thomas Neidhart

See Also:

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

Constructor Summary

Constructors

Constructor and Description
SaastamoinenModel(double t0, double p0, double r0) Create a new Saastamoinen model for the troposphere using the given environmental conditions.

Method Summary

Methods

Modifier and Type	Method and Description
double	calculatePathDelay(double elevation, double height) Calculates the tropospheric path delay for the signal path from a ground station to a satellite.
double	calculateSignalDelay(double elevation, double height) Calculates the tropospheric signal delay for the signal path from a ground station to a satellite.
static SaastamoinenModel	getStandardModel() Create a new Saastamoinen model using a standard atmosphere model.

Methods inherited from class java.lang.Object

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

Constructor Detail

SaastamoinenModel

public SaastamoinenModel(double t0,
                 double p0,
                 double r0)

Create a new Saastamoinen model for the troposphere using the given environmental conditions.

Parameters:

t0 - the temperature at the station [K]

p0 - the atmospheric pressure at the station [mbar]

r0 - the humidity at the station [percent] (50% -> 0.5)

Method Detail

getStandardModel

public static SaastamoinenModel getStandardModel()

Create a new Saastamoinen model using a standard atmosphere model.

• temperature: 18 degree Celsius
• pressure: 1013.25 mbar
• humidity: 50%

Returns:

a Saastamoinen model with standard environmental values

calculatePathDelay

public double calculatePathDelay(double elevation,
                        double height)

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

Specified by:

calculatePathDelay in interface TroposphericDelayModel

Parameters:

elevation - the elevation of the satellite in degrees

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

Returns:

the path delay due to the troposphere in m

calculateSignalDelay

public double calculateSignalDelay(double elevation,
                          double height)

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

   calculatePathDelay(double, double)/Constants.SPEED_OF_LIGHT
 

Specified by:

calculateSignalDelay in interface TroposphericDelayModel

Parameters:

elevation - the elevation of the satellite in degrees

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

Returns:

the signal delay due to the troposphere in s