POM00 Subroutine

  1. astro_module.f90
  2. astro_module
  3. POM00

public subroutine POM00(xp, yp, sp, rpom)

Form the matrix of polar motion for a given date, IAU 2000.

Status: support routine.

Notes

  1. XP and YP are the coordinates (in radians) of the Celestial Intermediate Pole with respect to the International Terrestrial Reference System (see IERS Conventions 2003), measured along the meridians to 0 and 90 deg west respectively.

  2. SP is the TIO locator s', in radians, which positions the Terrestrial Intermediate Origin on the equator. It is obtained from polar motion observations by numerical integration, and so is in essence unpredictable. However, it is dominated by a secular drift of about 47 microarcseconds per century, and so can be taken into account by using s' = -47*t, where t is centuries since J2000.0. The routine SP00 implements this approximation.

  3. The matrix operates in the sense V(TRS) = RPOM * V(CIP), meaning that it is the final rotation when computing the pointing direction to a celestial source.

Reference

  • McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003), IERS Technical Note No. 32, BKG (2004)

History

  • IAU SOFA revision: 2009 December 15

Arguments

TypeIntentOptionalAttributesName
real(kind=wp), intent(in) :: xp

coordinates of the pole (radians, Note 1)
real(kind=wp), intent(in) :: yp

coordinates of the pole (radians, Note 1)
real(kind=wp), intent(in) :: sp

the TIO locator s' (radians, Note 2)
real(kind=wp), intent(out), dimension(3,3):: rpom

polar-motion matrix (Note 3)

Calls

proc~~pom00~~CallsGraph proc~pom00 POM00 proc~ir IR proc~pom00->proc~ir proc~rz RZ proc~pom00->proc~rz proc~rx RX proc~pom00->proc~rx proc~ry RY proc~pom00->proc~ry

Called by

proc~~pom00~~CalledByGraph proc~pom00 POM00 proc~pvtob PVTOB proc~pvtob->proc~pom00 proc~c2t00a C2T00A proc~c2t00a->proc~pom00 proc~c2txy C2TXY proc~c2txy->proc~pom00 proc~c2t06a C2T06A proc~c2t06a->proc~pom00 proc~c2tpe C2TPE proc~c2tpe->proc~pom00 proc~c2t00b C2T00B proc~c2t00b->proc~pom00 proc~apco APCO proc~apco->proc~pvtob proc~apio APIO proc~apio->proc~pvtob proc~apco13 APCO13 proc~apco13->proc~apco proc~apio13 APIO13 proc~apio13->proc~apio proc~atco13 ATCO13 proc~atco13->proc~apco13 proc~atoi13 ATOI13 proc~atoi13->proc~apio13 proc~atio13 ATIO13 proc~atio13->proc~apio13 proc~atoc13 ATOC13 proc~atoc13->proc~apco13

Contents

Source Code

POM00

Source Code

    subroutine POM00 ( xp, yp, sp, rpom )

    implicit none

    real(wp),intent(in) :: xp !! coordinates of the pole (radians, Note 1)
    real(wp),intent(in) :: yp !! coordinates of the pole (radians, Note 1)
    real(wp),intent(in) :: sp !! the TIO locator s' (radians, Note 2)
    real(wp),dimension(3,3),intent(out) :: rpom !! polar-motion matrix (Note 3)

    !  Construct the matrix.
    call IR ( rpom )
    call RZ ( sp, rpom )
    call RY ( -xp, rpom )
    call RX ( -yp, rpom )

    end subroutine POM00