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Diffstat (limited to 'src/slalib/pvobs.f')
-rw-r--r-- | src/slalib/pvobs.f | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/src/slalib/pvobs.f b/src/slalib/pvobs.f new file mode 100644 index 0000000..116bc06 --- /dev/null +++ b/src/slalib/pvobs.f @@ -0,0 +1,59 @@ + SUBROUTINE sla_PVOBS (P, H, STL, PV) +*+ +* - - - - - - +* P V O B S +* - - - - - - +* +* Position and velocity of an observing station (double precision) +* +* Given: +* P dp latitude (geodetic, radians) +* H dp height above reference spheroid (geodetic, metres) +* STL dp local apparent sidereal time (radians) +* +* Returned: +* PV dp(6) position/velocity 6-vector (AU, AU/s, true equator +* and equinox of date) +* +* Called: sla_GEOC +* +* IAU 1976 constants are used. +* +* P.T.Wallace Starlink 14 November 1994 +* +* Copyright (C) 1995 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + DOUBLE PRECISION P,H,STL,PV(6) + + DOUBLE PRECISION R,Z,S,C,V + +* Mean sidereal rate (at J2000) in radians per (UT1) second + DOUBLE PRECISION SR + PARAMETER (SR=7.292115855306589D-5) + + + +* Geodetic to geocentric conversion + CALL sla_GEOC(P,H,R,Z) + +* Functions of ST + S=SIN(STL) + C=COS(STL) + +* Speed + V=SR*R + +* Position + PV(1)=R*C + PV(2)=R*S + PV(3)=Z + +* Velocity + PV(4)=-V*S + PV(5)=V*C + PV(6)=0D0 + + END |