ds2c6.f

      SUBROUTINE sla_DS2C6 (A, B, R, AD, BD, RD, V)
*+
*     - - - - - -
*      D S 2 C 6
*     - - - - - -
*
*  Conversion of position & velocity in spherical coordinates
*  to Cartesian coordinates
*
*  (double precision)
*
*  Given:
*     A     dp      longitude (radians)
*     B     dp      latitude (radians)
*     R     dp      radial coordinate
*     AD    dp      longitude derivative (radians per unit time)
*     BD    dp      latitude derivative (radians per unit time)
*     RD    dp      radial derivative
*
*  Returned:
*     V     dp(6)   Cartesian position & velocity vector
*
*  P.T.Wallace   Starlink   10 July 1993
*
*  Copyright (C) 1995 Rutherford Appleton Laboratory
*
*  License:
*    This program is free software; you can redistribute it and/or modify
*    it under the terms of the GNU General Public License as published by
*    the Free Software Foundation; either version 2 of the License, or
*    (at your option) any later version.
*
*    This program is distributed in the hope that it will be useful,
*    but WITHOUT ANY WARRANTY; without even the implied warranty of
*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*    GNU General Public License for more details.
*
*    You should have received a copy of the GNU General Public License
*    along with this program (see SLA_CONDITIONS); if not, write to the 
*    Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
*    Boston, MA  02111-1307  USA
*
*-

      IMPLICIT NONE

      DOUBLE PRECISION A,B,R,AD,BD,RD,V(6)

      DOUBLE PRECISION SA,CA,SB,CB,RCB,X,Y,RBD,W



*  Useful functions
      SA=SIN(A)
      CA=COS(A)
      SB=SIN(B)
      CB=COS(B)
      RCB=R*CB
      X=RCB*CA
      Y=RCB*SA
      RBD=R*BD
      W=RBD*SB-CB*RD

*  Position
      V(1)=X
      V(2)=Y
      V(3)=R*SB

*  Velocity
      V(4)=-Y*AD-W*CA
      V(5)=X*AD-W*SA
      V(6)=RBD*CB+SB*RD

      END