jpl_ephemeris Derived Type

type, public, extends(ephemeris_class) :: jpl_ephemeris

Main class for accessing a JPL ephemeris file.


Inherits

type~~jpl_ephemeris~~InheritsGraph type~jpl_ephemeris jpl_ephemeris type~ephemeris_class ephemeris_class type~jpl_ephemeris->type~ephemeris_class

Components

Type Visibility Attributes Name Initial
character(len=:), public, allocatable :: namfil

name of the binary ephemeris file
integer, public :: ksize = 2036

ksize must be set by the user according to the ephemeris to be read: for de200, set ksize=1652, for de405, set ksize=2036, for de406, set ksize=1456, for de414, set ksize=2036, for de418, set ksize=2036, for de421, set ksize=2036, for de422, set ksize=2036, for de423, set ksize=2036, for de424, set ksize=2036, for de430, set ksize=2036.
integer, public, dimension(3,13) :: ipt = 0

ipt(39)
real(kind=wp), public, dimension(nmax) :: cval = 0.0_wp
real(kind=wp), public, dimension(3) :: ss = 0.0_wp
real(kind=wp), public :: au = 0.0_wp
real(kind=wp), public :: emrat = 0.0_wp
integer, public :: ncon = 0
integer, public :: numde = 0
real(kind=wp), public, dimension(6) :: pvsun = 0.0_wp

dp 6-word array containing the barycentric position and velocity of the sun.
logical, public :: km = .true.

logical flag defining physical units of the output states. km = .true. : km and km/sec km = .false. : au and au/day for nutations and librations. angle unit is always radians.
logical, public :: bary = .false.

logical flag defining output center. only the 9 planets are affected. bary = .true. : center is solar-system barycenter bary = .false. : center is sun
character(len=6), public, dimension(14,3) :: ttl = ''
character(len=6), public, dimension(nmax) :: cnam = ''
logical, public :: initialized = .false.

is the ephemeris initialized?
integer, public :: nrfile = 0

file unit for the ephemeris file
integer, public :: nrl = -1

this was formerly in state
integer, public :: ncoeffs = 0
real(kind=wp), public, dimension(1500) :: buf = 0.0_wp
real(kind=wp), public, dimension(18) :: pc = 0.0_wp
real(kind=wp), public, dimension(18) :: vc = 0.0_wp
integer, public :: np = 2
integer, public :: nv = 3
real(kind=wp), public :: twot = 0.0_wp

Type-Bound Procedures

procedure, public :: get_rv => get_rv_from_jpl_ephemeris

  • private subroutine get_rv_from_jpl_ephemeris(me, et, targ, obs, rv, status_ok)

    Interface for the ephemeris_module.

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me
    real(kind=fat_wp), intent(in) :: et

    ephemeris time [sec]
    type(celestial_body), intent(in) :: targ

    target body
    type(celestial_body), intent(in) :: obs

    observer body
    real(kind=fat_wp), intent(out), dimension(6) :: rv

    state of targ w.r.t. obs [km,km/s] in ICRF frame
    logical, intent(out) :: status_ok

    true if there were no problems

procedure, public :: initialize => initialize_ephemeris

  • private subroutine initialize_ephemeris(me, filename, ksize, km, bary, status_ok)

    Initialize the ephemeris. This routine may be called to load a different ephemeris file. Otherwise, it is called on the first call to get_state, and loads the file specified in the module header.

    Read more…

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me
    character(len=*), intent(in) :: filename

    ephemeris file name
    integer, intent(in), optional :: ksize

    corresponding ksize
    logical, intent(in), optional :: km

    defining physical units of the output states. km = .true. : km and km/sec [default], km = .false. : au and au/day.
    logical, intent(in), optional :: bary

    logical flag defining output center. only the 9 planets are affected. bary = .true. : center is solar-system barycenter, bary = .false. : center is sun [default].
    logical, intent(out) :: status_ok

    true if there were not problems.

procedure, public :: get_state

  • private subroutine get_state(me, jd, ntarg, ncent, rrd, status_ok)

    This subroutine reads the JPL planetary ephemeris and gives the position and velocity of the point ntarg with respect to ncent.

    Read more…

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me
    real(kind=wp), intent(in) :: jd

    d.p. Julian ephemeris date at which interpolation is wanted.
    integer, intent(in) :: ntarg

    integer number of 'target' point.
    integer, intent(in) :: ncent

    integer number of 'center' point.
    real(kind=wp), intent(out), dimension(6) :: rrd

    output 6-word d.p. array containing position and velocity of point ntarg relative to ncent. the units are AU and AU/day (or km and km/sec if me%km=.true.). For librations the units are radians and radians per day. In the case of nutations the first four words of rrd will be set to nutations and rates, having units of radians and radians/day.
    logical, intent(out) :: status_ok

    true if there were no problems

procedure, public :: get_constants

  • private subroutine get_constants(me, nam, val, sss, n)

    Obtain the constants from the ephemeris file.

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me
    character(len=6), intent(out), dimension(:) :: nam

    array of constant names
    real(kind=wp), intent(out), dimension(:) :: val

    array of values of constants
    real(kind=wp), intent(out), dimension(3) :: sss

    jd start, jd stop, step of ephemeris
    integer, intent(out) :: n

    number of entries in nam and val arrays

procedure, public :: close => close_ephemeris

  • private subroutine close_ephemeris(me)

    Close the ephemeris.

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me

procedure, public :: interp

  • private subroutine interp(me, buf, t, ncf, ncm, na, ifl, pv)

    this subroutine differentiates and interpolates a set of chebyshev coefficients to give position and velocity.

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me
    real(kind=wp), dimension(ncf,ncm,*) :: buf

    1st location of array of d.p. chebyshev coefficients of position
    real(kind=wp), intent(in), dimension(2) :: t
    integer, intent(in) :: ncf Read more…
    integer, intent(in) :: ncm Read more…
    integer, intent(in) :: na

    (i.e., # of sub-intervals in full interval)

    Read more…
    integer, intent(in) :: ifl

    integer flag = 1 for positions only = 2 for pos and vel
    real(kind=wp), dimension(ncm,*) :: pv

    interpolated quantities requested. dimension expected is pv(ncm,ifl), dp.

procedure, public :: state

  • private subroutine state(me, et2, list, pv, pnut, status_ok)

    This subroutine reads and interpolates the JPL planetary ephemeris file.

    Read more…

    Arguments

    Type IntentOptional Attributes Name
    class(jpl_ephemeris), intent(inout) :: me
    real(kind=wp), intent(in), dimension(2) :: et2

    2-word Julian ephemeris epoch at which interpolation is wanted. any combination of et2(1)+et2(2) which falls within the time span on the file is a permissible epoch.

    Read more…
    integer, intent(in), dimension(12) :: list

    12-word integer array specifying what interpolation is wanted for each of the bodies on the file. list(i) = 0 : no interpolation for body i, list(i) = 1 : position only, list(i) = 2 : position and velocity.

    Read more…
    real(kind=wp), intent(out), dimension(6,11) :: pv

    dp 6 x 11 array that will contain requested interpolated quantities (other than nutation, stored in pnut). the body specified by list(i) will have its state in the array starting at pv(1,i). (on any given call, only those words in pv which are affected by the first 10 list entries, and by list(12) if librations are on the file, are set. the rest of the pv array is untouched.) the order of components starting in pv(1,i) is: x,y,z,dx,dy,dz.

    Read more…
    real(kind=wp), intent(out), dimension(4) :: pnut

    dp 4-word array that will contain nutations and rates, depending on the setting of list(11). the order of quantities in pnut is:

    Read more…
    logical, intent(out) :: status_ok

    true if there were no problems

Source Code

    type,extends(ephemeris_class),public :: jpl_ephemeris

        !! Main class for accessing a JPL ephemeris file.

        character(len=:),allocatable :: namfil  !! name of the binary ephemeris file

        integer :: ksize = 2036  !! ksize must be set by the user according to the ephemeris to be read:
                                 !!   for ***de200***, set `ksize=1652`,
                                 !!   for ***de405***, set `ksize=2036`,
                                 !!   for ***de406***, set `ksize=1456`,
                                 !!   for ***de414***, set `ksize=2036`,
                                 !!   for ***de418***, set `ksize=2036`,
                                 !!   for ***de421***, set `ksize=2036`,
                                 !!   for ***de422***, set `ksize=2036`,
                                 !!   for ***de423***, set `ksize=2036`,
                                 !!   for ***de424***, set `ksize=2036`,
                                 !!   for ***de430***, set `ksize=2036`.

        !ephhdr
        integer,dimension(3,13)  :: ipt   = 0       !! ipt(39)
        real(wp),dimension(nmax) :: cval  = 0.0_wp
        real(wp),dimension(3)    :: ss    = 0.0_wp
        real(wp)                 :: au    = 0.0_wp
        real(wp)                 :: emrat = 0.0_wp
        integer                  :: ncon  = 0
        integer                  :: numde = 0

        !stcomx
        real(wp),dimension(6) :: pvsun = 0.0_wp   !! dp 6-word array containing the barycentric position and
                                                  !! velocity of the sun.
        logical               :: km    = .true.   !! logical flag defining physical units of the output states.
                                                  !!   km = .true.  : km and km/sec
                                                  !!   km = .false. : au and au/day
                                                  !! for nutations and librations.  angle unit is always radians.
        logical               :: bary  = .false.  !! logical flag defining output center.
                                                  !! only the 9 planets are affected.
                                                  !!   bary = .true.  : center is solar-system barycenter
                                                  !!   bary = .false. : center is sun

        !chrhdr
        character(len=6),dimension(14,3) :: ttl  = ''
        character(len=6),dimension(nmax) :: cnam = ''

        logical :: initialized = .false.  !! is the ephemeris initialized?
        integer :: nrfile      = 0        !! file unit for the ephemeris file
        integer :: nrl         = -1       !! this was formerly in state
        integer :: ncoeffs     = 0

        ! formerly in state:
        real(wp),dimension(1500) :: buf = 0.0_wp

        ! formerly in interp:
        real(wp),dimension(18) :: pc = 0.0_wp
        real(wp),dimension(18) :: vc = 0.0_wp
        integer                :: np = 2
        integer                :: nv = 3
        real(wp)               :: twot = 0.0_wp

    contains

        procedure,public :: get_rv => get_rv_from_jpl_ephemeris

        procedure,public :: initialize => initialize_ephemeris
        procedure,public :: get_state
        procedure,public :: get_constants
        procedure,public :: close => close_ephemeris

        procedure :: interp
        procedure :: state

    end type jpl_ephemeris