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C $Id: look.f 3304 2011-01-17 15:25:59Z brideout $
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C
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SUBROUTINE LOOK(SR,SLAT,SLON,PR,GLAT,GLON,AZ,EL,RANGE)
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C
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C jmh - 1/80 ans fortran 66
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C
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C LOOK calculates the azimuth, elevation and range from a radar
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C of a specified point.
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C
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C Input:
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C SR - distance of station from center of earth (km)
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C SLAT - geocentric latitude of station (deg)
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C SLON - longitude of station (deg)
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C PR - distance from center of earth of observation point (km)
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C GLAT - observation point geocentric latitude (deg)
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C GLON - observation point longitude (deg)
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C
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C Output:
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C AZ - radar azimuth (deg)
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C EL - radar elevation (deg)
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C RANGE - radar range (km)
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C
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C ...calculate "observation-point" earth centered cartesian coords..
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C .. Scalar Arguments ..
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DOUBLE PRECISION AZ,EL,GLAT,GLON,PR,RANGE,SLAT,SLON,SR
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C ..
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C .. Local Scalars ..
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DOUBLE PRECISION RP,RR,RT,SP1,SR1,ST2
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C ..
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C .. Local Arrays ..
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DOUBLE PRECISION P(3),R(3),S(3)
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C ..
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C .. External Subroutines ..
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EXTERNAL CSCONV,VCTCNV,VSUB
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C ..
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CALL CSCONV(P(1),P(2),P(3),PR,90.0D0-GLAT,GLON,2)
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C
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C ...calculate "station" earth centered cartesian coordinates...
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CALL CSCONV(S(1),S(2),S(3),SR,90.0D0-SLAT,SLON,2)
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C
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C ...calculate "line-of-sight" earth centered cartesian coords...
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CALL VSUB(P,S,R)
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C
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C ...calculate "line-of-sight" station centered cartesian coords...
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CALL VCTCNV(R(1),R(2),R(3),S(1),S(2),S(3),RR,RT,RP,SR1,ST2,SP1,1)
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C
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C ...calculate "line-of-sight" station centered spherical coords...
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CALL CSCONV(RT,RP,RR,RANGE,EL,AZ,1)
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EL = 90.D0 - EL
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AZ = 180.D0 - AZ
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RETURN
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C
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END
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