org.orekit.forces.drag.atmosphere

Class HarrisPriester

java.lang.Object

org.orekit.forces.drag.atmosphere.HarrisPriester

All Implemented Interfaces:

Serializable, Atmosphere

public class HarrisPriester
extends Object
implements Atmosphere

This atmosphere model is the realization of the Modified Harris-Priester model.

This model is a static one that takes into account the diurnal density bulge. It doesn't need any space weather data but a density vs. altitude table, which depends on solar activity.

The implementation relies on the book:
Satellite Orbits
Oliver Montenbruck, Eberhard Gill
Springer 2005

Author:

Pascal Parraud

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
HarrisPriester(PVCoordinatesProvider sun, OneAxisEllipsoid earth) Simple constructor for Modified Harris-Priester atmosphere model.
HarrisPriester(PVCoordinatesProvider sun, OneAxisEllipsoid earth, double n) Constructor for Modified Harris-Priester atmosphere model.
HarrisPriester(PVCoordinatesProvider sun, OneAxisEllipsoid earth, double[][] tabAltRho) Constructor for Modified Harris-Priester atmosphere model.
HarrisPriester(PVCoordinatesProvider sun, OneAxisEllipsoid earth, double[][] tabAltRho, double n) Constructor for Modified Harris-Priester atmosphere model.

Method Summary

Modifier and Type	Method and Description
double	getDensity(AbsoluteDate date, Vector3D position, Frame frame) Get the local density at some position.
<T extends RealFieldElement<T>> T	getDensity(FieldAbsoluteDate<T> date, FieldVector3D<T> position, Frame frame) Get the local density at some position.
<T extends RealFieldElement<T>> T	getDensity(Vector3D sunInEarth, FieldVector3D<T> posInEarth) Get the local density.
double	getDensity(Vector3D sunInEarth, Vector3D posInEarth) Get the local density.
Frame	getFrame() Get the frame of the central body.
double	getMaxAlt() Get the maximal altitude for the model.
double	getMinAlt() Get the minimal altitude for the model.
double[][]	getTabDensity() Get the current density table.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.forces.drag.atmosphere.Atmosphere

getVelocity, getVelocity

Constructor Detail

HarrisPriester

public HarrisPriester(PVCoordinatesProvider sun,
                      OneAxisEllipsoid earth)

Simple constructor for Modified Harris-Priester atmosphere model.

The cosine exponent value is set to 4 by default.

The default embedded density table is the one given in the referenced book from Montenbruck & Gill. It is given for mean solar activity and spreads over 100 to 1000 km.

Parameters:

sun - the sun position

earth - the earth body shape

HarrisPriester

public HarrisPriester(PVCoordinatesProvider sun,
                      OneAxisEllipsoid earth,
                      double n)

Constructor for Modified Harris-Priester atmosphere model.

Recommanded values for the cosine exponent spread over the range 2, for low inclination orbits, to 6, for polar orbits.

The default embedded density table is the one given in the referenced book from Montenbruck & Gill. It is given for mean solar activity and spreads over 100 to 1000 km.

Parameters:

sun - the sun position

earth - the earth body shape

n - the cosine exponent

HarrisPriester

public HarrisPriester(PVCoordinatesProvider sun,
                      OneAxisEllipsoid earth,
                      double[][] tabAltRho)

Constructor for Modified Harris-Priester atmosphere model.

The provided density table must be an array such as:

• tabAltRho[][0] = altitude (m)
• tabAltRho[][1] = min density (kg/m³)
• tabAltRho[][2] = max density (kg/m³)

The altitude must be increasing without limitation in range. The internal density table is a copy of the provided one.

The cosine exponent value is set to 4 by default.

Parameters:

sun - the sun position

earth - the earth body shape

tabAltRho - the density table

HarrisPriester

public HarrisPriester(PVCoordinatesProvider sun,
                      OneAxisEllipsoid earth,
                      double[][] tabAltRho,
                      double n)

Constructor for Modified Harris-Priester atmosphere model.

Recommanded values for the cosine exponent spread over the range 2, for low inclination orbits, to 6, for polar orbits.

The provided density table must be an array such as:

• tabAltRho[][0] = altitude (m)
• tabAltRho[][1] = min density (kg/m³)
• tabAltRho[][2] = max density (kg/m³)

The altitude must be increasing without limitation in range. The internal density table is a copy of the provided one.

Parameters:

sun - the sun position

earth - the earth body shape

tabAltRho - the density table

n - the cosine exponent

Method Detail

getFrame

public Frame getFrame()

Get the frame of the central body.

Specified by:

getFrame in interface Atmosphere

Returns:

frame of the central body.

getTabDensity

public double[][] getTabDensity()

Get the current density table.

The density table is an array such as:

• tabAltRho[][0] = altitude (m)
• tabAltRho[][1] = min density (kg/m³)
• tabAltRho[][2] = max density (kg/m³)

The altitude must be increasing without limitation in range.

The returned density table is a copy of the current one.

Returns:

density vs. altitude table

getMinAlt

public double getMinAlt()

Get the minimal altitude for the model.

No computation is possible below this altitude.

Returns:

the minimal altitude (m)

getMaxAlt

public double getMaxAlt()

Get the maximal altitude for the model.

Above this altitude, density is assumed to be zero.

Returns:

the maximal altitude (m)

getDensity

public double getDensity(Vector3D sunInEarth,
                         Vector3D posInEarth)
                  throws OrekitException

Get the local density.

Parameters:

sunInEarth - position of the Sun in Earth frame (m)

posInEarth - target position in Earth frame (m)

Returns:

the local density (kg/m³)

Throws:

OrekitException - if altitude is below the model minimal altitude

getDensity

public <T extends RealFieldElement<T>> T getDensity(Vector3D sunInEarth,
                                                    FieldVector3D<T> posInEarth)
                                             throws OrekitException

Get the local density.

Type Parameters:

T - instance of RealFieldElement

Parameters:

sunInEarth - position of the Sun in Earth frame (m)

posInEarth - target position in Earth frame (m)

Returns:

the local density (kg/m³)

Throws:

OrekitException - if altitude is below the model minimal altitude

getDensity

public double getDensity(AbsoluteDate date,
                         Vector3D position,
                         Frame frame)
                  throws OrekitException

Get the local density at some position.

Specified by:

getDensity in interface Atmosphere

Parameters:

date - current date

position - current position

frame - the frame in which is defined the position

Returns:

local density (kg/m³)

Throws:

OrekitException - if some frame conversion cannot be performed or if altitude is below the model minimal altitude

getDensity

public <T extends RealFieldElement<T>> T getDensity(FieldAbsoluteDate<T> date,
                                                    FieldVector3D<T> position,
                                                    Frame frame)
                                             throws OrekitException

Get the local density at some position.

Specified by:

getDensity in interface Atmosphere

Type Parameters:

T - implements a RealFieldElement

Parameters:

date - current date

position - current position

frame - the frame in which is defined the position

Returns:

local density (kg/m³)

Throws:

OrekitException - if some frame conversion cannot be performed or if altitude is below the model minimal altitude