src / astro

psEarthOrientation.h File Reference

Detailed Description

Function prototypes for earth orientation calculations transformation.

Author:: Dave Robbins, MHPCC
Robert Daniel DeSonia, MHPCC

Version:

Revision: 1.11

Name: rel9_0

Date:

Date: 2005/11/17 03:59:05

Definition in file psEarthOrientation.h.

#include "psCoord.h"
#include "psTime.h"
#include "psSphereOps.h"

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Enumerations

enum psPrecessMethod { PS_PRECESS_ROUGH, PS_PRECESS_COMPLETE, PS_PRECESS_IAU2000A }

Method for spherical precession used to specify the level of detail used in calculation. More...

Functions

bool p_psEOCInit (void)

Initialize EOC.

bool p_psEOCFinalize (void)

Finalize EOC after using functions that make calls to eocInit for time table data.

psEarthPole * psEarthPoleAlloc (void)

Allocates a new psEarthPole structure.

psSphere * psAberration (psSphere *apparent, const psSphere *actual, const psSphere *direction, double speed)

Calculates the actual position of a star, given its apparent position and the velocity vector of the observer.

psSphere * psGravityDeflection (psSphere *apparent, psSphere *actual, psSphere *sun)

Calculates the actual position of a star, given its apparent position and the position of the sun.

psEarthPole * psEOC_PrecessionModel (const psTime *time)

Calculates the components of the rotation between the CEO and GCRS frames, X, Y, and s, using the IAU2000A precession & nutation model.

psEarthPole * psEOC_PrecessionCorr (const psTime *time, psTimeBulletin bulletin)

Provides interpolated corrections to the X and Y components of the polar coordinates from the tables provided by the IERS, just as it does for UT1 and polar motion.

psSphereRot * psSphereRot_CEOtoGCRS (const psEarthPole *pole)

Constructs the spherical rotation for transforming from CEO to GCRS coordinates.

psSphereRot * psSphereRot_TEOtoCEO (const psTime *time)

Calculates the rotation of the Earth about the CIP.

psEarthPole * psEOC_GetPolarMotion (const psTime *time, psTimeBulletin bulletin)

Provides interpolated values of the polar motion components extracted from the IERS tables.

psEarthPole * psEOC_PolarTideCorr (const psTime *time)

Provides tidal corrections to the polar motion components using the Ray model of Simon et al.

psEarthPole * psEOC_NutationCorr (psTime *time)

Provides the additional corrections due to nutation terms with periods less than or equal to two days, as well as the correction to the s-prime component of polar motion.

psSphereRot * psSphereRot_ITRStoTEO (const psEarthPole *motion)

Converts the polar motion corrections to a spherical rotation.

Enumeration Type Documentation

enum psPrecessMethod

Method for spherical precession used to specify the level of detail used in calculation.

See also:
psSpherePrecess

Enumeration values:

PS_PRECESS_ROUGH roughest, lowest level of detail

PS_PRECESS_COMPLETE complete level of detail

PS_PRECESS_IAU2000A highest level of detail

Definition at line 40 of file psEarthOrientation.h.

Function Documentation

bool p_psEOCFinalize ( void )

Finalize EOC after using functions that make calls to eocInit for time table data.

Returns:
bool: True if successful, otherwise false.

bool p_psEOCInit ( void )

Initialize EOC.
Parses IERS table data and creates the polynomials used by certain EOC functions.

Returns:
bool: True if successful, otherwise false.

psSphere* psAberration ( psSphere * apparent,

const psSphere * actual,

const psSphere * direction,

double speed

)

Calculates the actual position of a star, given its apparent position and the velocity vector of the observer.
The actual and apparent positions are represented as psSphere entries, as is the direction of motion. The speed in that direction is given in units of the speed of light. If the value of actual is NULL, a new psSphere is allocated, otherwise the point to actual is used for the result.

Returns:
psSphere*: the actual position of a star.

Parameters:

apparent apparent position of star

actual actual position of star

direction direction of motion of observer

speed speed of motion of observer

psEarthPole* psEarthPoleAlloc ( void )

Allocates a new psEarthPole structure.

psEarthPole* psEOC_GetPolarMotion ( const psTime * time,

psTimeBulletin bulletin

)

Provides interpolated values of the polar motion components extracted from the IERS tables.

Returns:
psEarthPole*: interpolated polar motion components.

Parameters:

time specified time

bulletin IERS tables for polar coordinate components.

psEarthPole* psEOC_NutationCorr ( psTime * time )

Provides the additional corrections due to nutation terms with periods less than or equal to two days, as well as the correction to the s-prime component of polar motion.

Returns:
psEarthPole*: corrected polar motion components.

Parameters:

time specified time

psEarthPole* psEOC_PolarTideCorr ( const psTime * time )

Provides tidal corrections to the polar motion components using the Ray model of Simon et al.

Returns:
psEarthPole*: corrected polar motion components.

Parameters:

time specified time

psEarthPole* psEOC_PrecessionCorr ( const psTime * time,

psTimeBulletin bulletin

)

Provides interpolated corrections to the X and Y components of the polar coordinates from the tables provided by the IERS, just as it does for UT1 and polar motion.

Returns:
psEarthPole*: interpolated corrections to the precession components.

Parameters:

time specified time

bulletin IERS tables for polar coordinate components.

psEarthPole* psEOC_PrecessionModel ( const psTime * time )

Calculates the components of the rotation between the CEO and GCRS frames, X, Y, and s, using the IAU2000A precession & nutation model.
The input time may be represented in any format other than UT1. This routine must give results identical to the IERS XYS2000A subroutine.

Returns:
psEarthPole*: the calculated components of the rotation.

Parameters:

time specified time

psSphere* psGravityDeflection ( psSphere * apparent,

psSphere * actual,

psSphere * sun

)

Calculates the actual position of a star, given its apparent position and the position of the sun.
The actual and apparent positions are represented as psSphere entries, as is position of the sun. If the value of actual is NULL, a new psSphere is allocated, otherwise the point to actual is used for the result.

Returns:
psSphere*: the apparent position of a star.

Parameters:

apparent apparent position of star

actual actual position of star

sun position of the sun

psSphereRot* psSphereRot_CEOtoGCRS ( const psEarthPole * pole )

Constructs the spherical rotation for transforming from CEO to GCRS coordinates.
The resulting psSphereRot may be used to determine the rotation from CIP/CEO to GCRS. This function must give results identical to the IERS BPN2000.

Returns:
psSphereRot*: spherical rotation for CEO to GCRS transformation.

Parameters:

pole input coordinates to transform

psSphereRot* psSphereRot_ITRStoTEO ( const psEarthPole * motion )

Converts the polar motion corrections to a spherical rotation.
This function should give identical results to the IERS POM2000 subroutine.

Returns:
psSphereRot*: ITRS to TEO sphere rotation.

Parameters:

motion corrected polar motion components

psSphereRot* psSphereRot_TEOtoCEO ( const psTime * time )

Calculates the rotation of the Earth about the CIP.

Returns:
psSphereRot*: sphereical rotation

Parameters:

time specified time

Generated on Tue Dec 6 17:18:42 2005 for Pan-STARRS Foundation Library by

1.4.2


Enumerations
enum	psPrecessMethod { PS_PRECESS_ROUGH, PS_PRECESS_COMPLETE, PS_PRECESS_IAU2000A }
	Method for spherical precession used to specify the level of detail used in calculation. More...
Functions
bool	p_psEOCInit (void)
	Initialize EOC.
bool	p_psEOCFinalize (void)
	Finalize EOC after using functions that make calls to eocInit for time table data.
psEarthPole *	psEarthPoleAlloc (void)
	Allocates a new psEarthPole structure.
psSphere *	psAberration (psSphere apparent, const psSphere actual, const psSphere *direction, double speed)
	Calculates the actual position of a star, given its apparent position and the velocity vector of the observer.
psSphere *	psGravityDeflection (psSphere apparent, psSphere actual, psSphere *sun)
	Calculates the actual position of a star, given its apparent position and the position of the sun.
psEarthPole *	psEOC_PrecessionModel (const psTime *time)
	Calculates the components of the rotation between the CEO and GCRS frames, X, Y, and s, using the IAU2000A precession & nutation model.
psEarthPole *	psEOC_PrecessionCorr (const psTime *time, psTimeBulletin bulletin)
	Provides interpolated corrections to the X and Y components of the polar coordinates from the tables provided by the IERS, just as it does for UT1 and polar motion.
psSphereRot *	psSphereRot_CEOtoGCRS (const psEarthPole *pole)
	Constructs the spherical rotation for transforming from CEO to GCRS coordinates.
psSphereRot *	psSphereRot_TEOtoCEO (const psTime *time)
	Calculates the rotation of the Earth about the CIP.
psEarthPole *	psEOC_GetPolarMotion (const psTime *time, psTimeBulletin bulletin)
	Provides interpolated values of the polar motion components extracted from the IERS tables.
psEarthPole *	psEOC_PolarTideCorr (const psTime *time)
	Provides tidal corrections to the polar motion components using the Ray model of Simon et al.
psEarthPole *	psEOC_NutationCorr (psTime *time)
	Provides the additional corrections due to nutation terms with periods less than or equal to two days, as well as the correction to the s-prime component of polar motion.
psSphereRot *	psSphereRot_ITRStoTEO (const psEarthPole *motion)
	Converts the polar motion corrections to a spherical rotation.