SUBROUTINE VMF1 (AH,AW,DMJD,DLAT,ZD,VMF1H,VMF1W) *+ * - - - - - - - - - * 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). * 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 website * http://ggosatm.hg.tuwien.ac.at/DELAY/SITE/ * * 2) The mapping functions are dimensionless scale factors. * * Test case: * given input: AH = 0.00127683D0 * AW = 0.00060955D0 * DMJD = 55055D0 * DLAT = 0.6708665767D0 radians (NRAO, Green Bank, WV) * ZD = 1.278564131D0 radians * * expected output: VMF1H = 3.424342122738070593D0 * VMF1W = 3.448299714692572238D0 * * 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 * * Please mind that the coefficients in this paper are wrong. * The corrected version of the paper can be found at: * http://ggosatm.hg.tuwien.ac.at/DOCS/PAPERS/2006Boehm_etal_VMF1.pdf * * 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 * 2011 July 21 J. Boehm Changed latitude to ellipsoidal latitude * 2012 January 11 B.E. Stetzler Updated website in notes, removed reference * to old website, and added note in references * 2012 January 12 B.E. Stetzler Corrected test case input and output * mentioned in the header *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION AH, AW, DMJD, DLAT, ZD, VMF1H, VMF1W DOUBLE PRECISION DOY, BH, C0H, C11H, C10H, PHH, CH, SINE, BETA, . GAMMA, TOPCON, BW, CW, PI, TWOPI PARAMETER ( PI = 3.1415926535897932384626433D0 ) PARAMETER (TWOPI = 6.283185307179586476925287D0) *+--------------------------------------------------------------------- * Reference day is 28 January 1980 * This is taken from Niell (1996) to be consistent *---------------------------------------------------------------------- DOY = DMJD - 44239D0 + 1 - 28 BH = 0.0029D0; C0H = 0.062D0 IF (DLAT.LT.0D0) THEN ! southern hemisphere PHH = PI C11H = 0.007D0 C10H = 0.002D0 ELSE ! northern hemisphere PHH = 0D0 C11H = 0.005D0 C10H = 0.001D0 END IF CH = C0H + ((DCOS(DOY/365.25D0*TWOPI + PHH)+1D0)*C11H/2D0 . + C10H)*(1D0-DCOS(DLAT)) SINE = DSIN(PI/2D0 - ZD) BETA = BH/( SINE + CH ) GAMMA = AH/( SINE + BETA) TOPCON = (1D0 + AH/(1D0 + BH/(1D0 + CH))) VMF1H = TOPCON/(SINE+GAMMA) BW = 0.00146D0 CW = 0.04391D0 BETA = BW/( SINE + CW ) GAMMA = AW/( SINE + BETA) TOPCON = (1D0 + AW/(1D0 + BW/(1D0 + CW))) 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. 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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 * * *----------------------------------------------------------------------- END