Package org.orekit.models.earth.troposphere

Class CanonicalSaastamoinenModel

java.lang.Object

org.orekit.models.earth.troposphere.CanonicalSaastamoinenModel

All Implemented Interfaces:

TroposphericModel, ParameterDriversProvider

public class CanonicalSaastamoinenModel
extends Object
implements TroposphericModel

The canonical Saastamoinen model.

Estimates the path delay imposed to electro-magnetic signals by the troposphere according to the formula: \[ \delta = \frac{0.002277}{\cos z (1 - 0.00266\cos 2\varphi - 0.00028 h})} \left[P+(\frac{1255}{T}+0.005)e - B(h) \tan^2 z\right] \] with the following input data provided to the model:

• z: zenith angle
• P: atmospheric pressure
• T: temperature
• e: partial pressure of water vapor

Since:

12.1

Author:

Luc Maisonobe

See Also:

"J Saastamoinen, Atmospheric Correction for the Troposphere and Stratosphere in Radio Ranging of Satellites"

Field Summary

Fields

Modifier and Type	Field	Description
static double	DEFAULT_LOW_ELEVATION_THRESHOLD	Default lowest acceptable elevation angle [rad].

Constructor Summary

Constructors

Constructor	Description
CanonicalSaastamoinenModel()	Create a new Saastamoinen model for the troposphere using the given environmental conditions and table from the reference book.

Method Summary

Modifier and Type	Method	Description
double	getLowElevationThreshold()	Get the low elevation threshold value for path delay computation.
List<ParameterDriver>	getParametersDrivers()	Get the drivers for parameters.
<T extends CalculusFieldElement<T>> FieldTroposphericDelay<T>	pathDelay(FieldTrackingCoordinates<T> trackingCoordinates, FieldGeodeticPoint<T> point, FieldPressureTemperatureHumidity<T> weather, T[] parameters, FieldAbsoluteDate<T> date)	Calculates the tropospheric path delay for the signal path from a ground station to a satellite.
TroposphericDelay	pathDelay(TrackingCoordinates trackingCoordinates, GeodeticPoint point, PressureTemperatureHumidity weather, double[] parameters, AbsoluteDate date)	Calculates the tropospheric path delay for the signal path from a ground station to a satellite.
void	setLowElevationThreshold(double lowElevationThreshold)	Set the low elevation threshold value for path delay computation.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.utils.ParameterDriversProvider

getNbParametersDriversValue, getParameterDriver, getParameters, getParameters, getParameters, getParameters, getParametersAllValues, getParametersAllValues, isSupported

Field Detail

DEFAULT_LOW_ELEVATION_THRESHOLD

public static final double DEFAULT_LOW_ELEVATION_THRESHOLD

Default lowest acceptable elevation angle [rad].

See Also:

Constant Field Values

Constructor Detail

CanonicalSaastamoinenModel

public CanonicalSaastamoinenModel()

Create a new Saastamoinen model for the troposphere using the given environmental conditions and table from the reference book.

See Also:

HeightDependentPressureTemperatureHumidityConverter

Method Detail

pathDelay

public TroposphericDelay pathDelay(TrackingCoordinates trackingCoordinates,
                                   GeodeticPoint point,
                                   PressureTemperatureHumidity weather,
                                   double[] parameters,
                                   AbsoluteDate date)

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

The Saastamoinen model is not defined for altitudes below 0.0. for continuity reasons, we use the value for h = 0 when altitude is negative.

There are also numerical issues for elevation angles close to zero. For continuity reasons, elevations lower than a threshold will use the value obtained for the threshold itself.

Specified by:

pathDelay in interface TroposphericModel

Parameters:

trackingCoordinates - tracking coordinates of the satellite

point - station location

weather - weather parameters for constant default values)

parameters - tropospheric model parameters

date - current date

Returns:

the path delay due to the troposphere

See Also:

getLowElevationThreshold(), setLowElevationThreshold(double)

pathDelay

public <T extends CalculusFieldElement<T>> FieldTroposphericDelay<T> pathDelay(FieldTrackingCoordinates<T> trackingCoordinates,
                                                                               FieldGeodeticPoint<T> point,
                                                                               FieldPressureTemperatureHumidity<T> weather,
                                                                               T[] parameters,
                                                                               FieldAbsoluteDate<T> date)

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

The Saastamoinen model is not defined for altitudes below 0.0. for continuity reasons, we use the value for h = 0 when altitude is negative.

There are also numerical issues for elevation angles close to zero. For continuity reasons, elevations lower than a threshold will use the value obtained for the threshold itself.

Specified by:

pathDelay in interface TroposphericModel

Type Parameters:

T - type of the elements

Parameters:

trackingCoordinates - tracking coordinates of the satellite

point - station location

weather - weather parameters for constant default values)

parameters - tropospheric model parameters at current date

date - current date

Returns:

the path delay due to the troposphere

See Also:

getLowElevationThreshold(), setLowElevationThreshold(double)

getParametersDrivers

public List<ParameterDriver> getParametersDrivers()

Get the drivers for parameters.

Specified by:

getParametersDrivers in interface ParameterDriversProvider

Returns:

drivers for parameters

getLowElevationThreshold

public double getLowElevationThreshold()

Get the low elevation threshold value for path delay computation.

Returns:

low elevation threshold, in rad.

See Also:

pathDelay(TrackingCoordinates, GeodeticPoint, PressureTemperatureHumidity, double[], AbsoluteDate), pathDelay(FieldTrackingCoordinates, FieldGeodeticPoint, FieldPressureTemperatureHumidity, CalculusFieldElement[], FieldAbsoluteDate)

setLowElevationThreshold

public void setLowElevationThreshold(double lowElevationThreshold)

Set the low elevation threshold value for path delay computation.

Parameters:

lowElevationThreshold - The new value for the threshold [rad]

See Also:

pathDelay(TrackingCoordinates, GeodeticPoint, PressureTemperatureHumidity, double[], AbsoluteDate), pathDelay(FieldTrackingCoordinates, FieldGeodeticPoint, FieldPressureTemperatureHumidity, CalculusFieldElement[], FieldAbsoluteDate)