BP06 Subroutine

  1. astro_module.f90
  2. astro_module
  3. BP06

public subroutine BP06(date1, date2, rb, rp, rbp)

Frame bias and precession, IAU 2006.

Status: support routine.

Notes

  1. The TT date DATE1+DATE2 is a Julian Date, apportioned in any convenient way between the two arguments. For example, JD(TT)=2450123.7 could be expressed in any of these ways, among others:

        DATE1          DATE2

 2450123.7D0        0D0        (JD method)
  2451545D0      -1421.3D0     (J2000 method)
 2400000.5D0     50123.2D0     (MJD method)
 2450123.5D0       0.2D0       (date & time method)

    The JD method is the most natural and convenient to use in cases where the loss of several decimal digits of resolution is acceptable. The J2000 method is best matched to the way the argument is handled internally and will deliver the optimum resolution. The MJD method and the date & time methods are both good compromises between resolution and convenience.

  2. The matrix RB transforms vectors from GCRS to mean J2000.0 by applying frame bias.

  3. The matrix RP transforms vectors from mean J2000.0 to mean of date by applying precession.

  4. The matrix RBP transforms vectors from GCRS to mean of date by applying frame bias then precession. It is the product RP x RB.

References

  • Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855

  • Wallace, P.T. & Capitaine, N., 2006, Astron.Astrophys. 459, 981

History

  • IAU SOFA revision: 2013 August 21

Arguments

TypeIntentOptionalAttributesName
real(kind=wp), intent(in) :: date1

TT as a 2-part Julian Date (Note 1)
real(kind=wp), intent(in) :: date2

TT as a 2-part Julian Date (Note 1)
real(kind=wp), intent(out), dimension(3,3):: rb

frame bias matrix (Note 2)
real(kind=wp), intent(out), dimension(3,3):: rp

precession matrix (Note 3)
real(kind=wp), intent(out), dimension(3,3):: rbp

bias-precession matrix (Note 4)

Calls

proc~~bp06~~CallsGraph proc~bp06 BP06 proc~pfw06 PFW06 proc~bp06->proc~pfw06 proc~pmat06 PMAT06 proc~bp06->proc~pmat06 proc~rxr RXR proc~bp06->proc~rxr proc~tr TR proc~bp06->proc~tr proc~fw2m FW2M proc~bp06->proc~fw2m proc~obl06 OBL06 proc~pfw06->proc~obl06 proc~pmat06->proc~pfw06 proc~pmat06->proc~fw2m proc~ir IR proc~fw2m->proc~ir proc~rz RZ proc~fw2m->proc~rz proc~rx RX proc~fw2m->proc~rx

Contents

Source Code

BP06

Source Code

    subroutine BP06 ( date1, date2, rb, rp, rbp )

    implicit none

    real(wp),intent(in) :: date1 !! TT as a 2-part Julian Date (Note 1)
    real(wp),intent(in) :: date2 !! TT as a 2-part Julian Date (Note 1)
    real(wp),dimension(3,3),intent(out) :: rb !! frame bias matrix (Note 2)
    real(wp),dimension(3,3),intent(out) :: rp !! precession matrix (Note 3)
    real(wp),dimension(3,3),intent(out) :: rbp !! bias-precession matrix (Note 4)

    !  JD for MJD 0
    real(wp),parameter :: djm0 = 2400000.5_wp

    !  Reference epoch (J2000.0), MJD
    real(wp),parameter :: djm00 = 51544.5_wp

    real(wp) :: gamb, phib, psib, epsa, rbpw(3,3), rbt(3,3)

    !  B matrix.
    call PFW06 ( djm0, djm00, gamb, phib, psib, epsa )
    call FW2M ( gamb, phib, psib, epsa, rb )

    !  PxB matrix (temporary).
    call PMAT06 ( date1, date2, rbpw )

    !  P matrix.
    call TR ( rb, rbt )
    call RXR ( rbpw, rbt, rp )

    !  PxB matrix.
    call CR ( rbpw, rbp )

    end subroutine BP06