WSJT-X/lib/geocentric.f90
Joe Taylor f283ca5c62 Another bunch needesd for astro display.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@3839 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2014-03-05 20:14:36 +00:00

18 lines
438 B
Fortran

subroutine geocentric(alat,elev,hlt,erad)
implicit real*8 (a-h,o-z)
! IAU 1976 flattening f, equatorial radius a
f = 1.d0/298.257d0
a = 6378140.d0
c = 1.d0/sqrt(1.d0 + (-2.d0 + f)*f*sin(alat)*sin(alat))
arcf = (a*c + elev)*cos(alat)
arsf = (a*(1.d0 - f)*(1.d0 - f)*c + elev)*sin(alat)
hlt = datan2(arsf,arcf)
erad = sqrt(arcf*arcf + arsf*arsf)
erad = 0.001d0*erad
return
end subroutine geocentric