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/* ../src/vmf1.f -- translated by f2c (version 20090411).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
/* Subroutine */ int vmf1_(doublereal *ah, doublereal *aw, doublereal *dmjd,
doublereal *dlat, doublereal *zd, doublereal *vmf1h, doublereal *
vmf1w)
{
/* Builtin functions */
double cos(doublereal), sin(doublereal);
/* Local variables */
static doublereal bh, ch, bw, cw, c0h, c10h, c11h, phh, doy, beta, sine,
gamma, topcon;
/* + */
/* - - - - - - - - - */
/* V M F 1 */
/* - - - - - - - - - */
/* This routine is part of the International Earth Rotation and */
/* Reference Systems Service (IERS) Conventions software collection. */
/* This subroutine determines the Vienna Mapping Function 1 (VMF1) (Boehm et al, 2006). */
/* This is the site dependent version. */
/* In general, Class 1, 2, and 3 models represent physical effects that */
/* act on geodetic parameters while canonical models provide lower-level */
/* representations or basic computations that are used by Class 1, 2, or */
/* 3 models. */
/* Status: Class 1 model */
/* Class 1 models are those recommended to be used a priori in the */
/* reduction of raw space geodetic data in order to determine */
/* geodetic parameter estimates. */
/* Class 2 models are those that eliminate an observational */
/* singularity and are purely conventional in nature. */
/* Class 3 models are those that are not required as either Class */
/* 1 or 2. */
/* Canonical models are accepted as is and cannot be classified as a */
/* Class 1, 2, or 3 model. */
/* Given: */
/* AH d Hydrostatic coefficient a (Note 1) */
/* AW d Wet coefficient a (Note 1) */
/* DMJD d Modified Julian Date */
/* DLAT d Latitude given in radians (North Latitude) */
/* ZD d Zenith distance in radians */
/* Returned: */
/* VMF1H d Hydrostatic mapping function (Note 2) */
/* VMF1W d Wet mapping function (Note 2) */
/* Notes: */
/* 1) The coefficients can be obtained from the primary website */
/* http://ggosatm.hg.tuwien.ac.at/DELAY/ or the back-up website */
/* http://www.hg.tuwien.ac.at/~ecmwf1/. */
/* 2) The mapping functions are dimensionless scale factors. */
/* Test case: */
/* given input: AH = 0.00125711D0 */
/* AW = 0.00058801D0 */
/* DMJD = 55055D0 */
/* DLAT = 0.6708665767D0 radians (NRAO, Green Bank, WV) */
/* ZD = 1.278564131D0 radians */
/* expected output: VMF1H = 3.425054275537719128D0 */
/* VMF1W = 3.449100942061193553D0 */
/* References: */
/* Boehm, J., Werl, B., and Schuh, H., (2006), */
/* "Troposhere mapping functions for GPS and very long baseline */
/* interferometry from European Centre for Medium-Range Weather */
/* Forecasts operational analysis data," J. Geophy. Res., Vol. 111, */
/* B02406, doi:10.1029/2005JB003629 */
/* Petit, G. and Luzum, B. (eds.), IERS Conventions (2010), */
/* IERS Technical Note No. 36, BKG (2010) */
/* Revisions: */
/* 2005 October 02 J. Boehm Original code */
/* 2009 August 17 B.E. Stetzler Added header and copyright */
/* 2009 August 17 B.E. Stetzler More modifications and defined twopi */
/* 2009 August 17 B.E. Stetzler Provided test case */
/* 2009 August 17 B.E. Stetzler Capitalized all variables for FORTRAN 77 */
/* compatibility */
/* 2010 September 08 B.E. Stetzler Provided new primary website to obtain */
/* VMF coefficients */
/* ----------------------------------------------------------------------- */
/* +--------------------------------------------------------------------- */
/* Reference day is 28 January 1980 */
/* This is taken from Niell (1996) to be consistent */
/* ---------------------------------------------------------------------- */
doy = *dmjd - 44239. - 27;
bh = .0029;
c0h = .062;
if (*dlat < 0.) {
/* southern hemisphere */
phh = 3.1415926535897932384626433;
c11h = .007;
c10h = .002;
} else {
/* northern hemisphere */
phh = 0.;
c11h = .005;
c10h = .001;
}
ch = c0h + ((cos(doy / 365.25 * 6.283185307179586476925287 + phh) + 1.) *
c11h / 2. + c10h) * (1. - cos(*dlat));
sine = sin(1.5707963267948966 - *zd);
beta = bh / (sine + ch);
gamma = *ah / (sine + beta);
topcon = *ah / (bh / (ch + 1.) + 1.) + 1.;
*vmf1h = topcon / (sine + gamma);
bw = .00146;
cw = .04391;
beta = bw / (sine + cw);
gamma = *aw / (sine + beta);
topcon = *aw / (bw / (cw + 1.) + 1.) + 1.;
*vmf1w = topcon / (sine + gamma);
/* Finished. */
/* +---------------------------------------------------------------------- */
/* Copyright (C) 2008 */
/* IERS Conventions Center */
/* ================================== */
/* IERS Conventions Software License */
/* ================================== */
/* NOTICE TO USER: */
/* BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING TERMS AND CONDITIONS */
/* WHICH APPLY TO ITS USE. */
/* 1. The Software is provided by the IERS Conventions Center ("the */
/* Center"). */
/* 2. Permission is granted to anyone to use the Software for any */
/* purpose, including commercial applications, free of charge, */
/* subject to the conditions and restrictions listed below. */
/* 3. You (the user) may adapt the Software and its algorithms for your */
/* own purposes and you may distribute the resulting "derived work" */
/* to others, provided that the derived work complies with the */
/* following requirements: */
/* a) Your work shall be clearly identified so that it cannot be */
/* mistaken for IERS Conventions software and that it has been */
/* neither distributed by nor endorsed by the Center. */
/* b) Your work (including source code) must contain descriptions of */
/* how the derived work is based upon and/or differs from the */
/* original Software. */
/* c) The name(s) of all modified routine(s) that you distribute */
/* shall be changed. */
/* d) The origin of the IERS Conventions components of your derived */
/* work must not be misrepresented; you must not claim that you */
/* wrote the original Software. */
/* e) The source code must be included for all routine(s) that you */
/* distribute. This notice must be reproduced intact in any */
/* source distribution. */
/* 4. In any published work produced by the user and which includes */
/* results achieved by using the Software, you shall acknowledge */
/* that the Software was used in obtaining those results. */
/* 5. The Software is provided to the user "as is" and the Center makes */
/* no warranty as to its use or performance. The Center does not */
/* and cannot warrant the performance or results which the user may */
/* obtain by using the Software. The Center makes no warranties, */
/* express or implied, as to non-infringement of third party rights, */
/* merchantability, or fitness for any particular purpose. In no */
/* event will the Center be liable to the user for any consequential, */
/* incidental, or special damages, including any lost profits or lost */
/* savings, even if a Center representative has been advised of such */
/* damages, or for any claim by any third party. */
/* Correspondence concerning IERS Conventions software should be */
/* addressed as follows: */
/* Gerard Petit */
/* Internet email: gpetit[at]bipm.org */
/* Postal address: IERS Conventions Center */
/* Time, frequency and gravimetry section, BIPM */
/* Pavillon de Breteuil */
/* 92312 Sevres FRANCE */
/* or */
/* Brian Luzum */
/* Internet email: brian.luzum[at]usno.navy.mil */
/* Postal address: IERS Conventions Center */
/* Earth Orientation Department */
/* 3450 Massachusetts Ave, NW */
/* Washington, DC 20392 */
/* ----------------------------------------------------------------------- */
return 0;
} /* vmf1_ */
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