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Diffstat (limited to 'ast/erfa/apco13.c')
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diff --git a/ast/erfa/apco13.c b/ast/erfa/apco13.c new file mode 100644 index 0000000..cdd4d4f --- /dev/null +++ b/ast/erfa/apco13.c @@ -0,0 +1,287 @@ +#include "erfa.h" + +int eraApco13(double utc1, double utc2, double dut1, + double elong, double phi, double hm, double xp, double yp, + double phpa, double tc, double rh, double wl, + eraASTROM *astrom, double *eo) +/* +** - - - - - - - - - - +** e r a A p c o 1 3 +** - - - - - - - - - - +** +** For a terrestrial observer, prepare star-independent astrometry +** parameters for transformations between ICRS and observed +** coordinates. The caller supplies UTC, site coordinates, ambient air +** conditions and observing wavelength, and ERFA models are used to +** obtain the Earth ephemeris, CIP/CIO and refraction constants. +** +** The parameters produced by this function are required in the +** parallax, light deflection, aberration, and bias-precession-nutation +** parts of the ICRS/CIRS transformations. +** +** Given: +** utc1 double UTC as a 2-part... +** utc2 double ...quasi Julian Date (Notes 1,2) +** dut1 double UT1-UTC (seconds, Note 3) +** elong double longitude (radians, east +ve, Note 4) +** phi double latitude (geodetic, radians, Note 4) +** hm double height above ellipsoid (m, geodetic, Notes 4,6) +** xp,yp double polar motion coordinates (radians, Note 5) +** phpa double pressure at the observer (hPa = mB, Note 6) +** tc double ambient temperature at the observer (deg C) +** rh double relative humidity at the observer (range 0-1) +** wl double wavelength (micrometers, Note 7) +** +** Returned: +** astrom eraASTROM* star-independent astrometry parameters: +** pmt double PM time interval (SSB, Julian years) +** eb double[3] SSB to observer (vector, au) +** eh double[3] Sun to observer (unit vector) +** em double distance from Sun to observer (au) +** v double[3] barycentric observer velocity (vector, c) +** bm1 double sqrt(1-|v|^2): reciprocal of Lorenz factor +** bpn double[3][3] bias-precession-nutation matrix +** along double longitude + s' (radians) +** xpl double polar motion xp wrt local meridian (radians) +** ypl double polar motion yp wrt local meridian (radians) +** sphi double sine of geodetic latitude +** cphi double cosine of geodetic latitude +** diurab double magnitude of diurnal aberration vector +** eral double "local" Earth rotation angle (radians) +** refa double refraction constant A (radians) +** refb double refraction constant B (radians) +** eo double* equation of the origins (ERA-GST) +** +** Returned (function value): +** int status: +1 = dubious year (Note 2) +** 0 = OK +** -1 = unacceptable date +** +** Notes: +** +** 1) utc1+utc2 is quasi Julian Date (see Note 2), apportioned in any +** convenient way between the two arguments, for example where utc1 +** is the Julian Day Number and utc2 is the fraction of a day. +** +** However, JD cannot unambiguously represent UTC during a leap +** second unless special measures are taken. The convention in the +** present function is that the JD day represents UTC days whether +** the length is 86399, 86400 or 86401 SI seconds. +** +** Applications should use the function eraDtf2d to convert from +** calendar date and time of day into 2-part quasi Julian Date, as +** it implements the leap-second-ambiguity convention just +** described. +** +** 2) The warning status "dubious year" flags UTCs that predate the +** introduction of the time scale or that are too far in the +** future to be trusted. See eraDat for further details. +** +** 3) UT1-UTC is tabulated in IERS bulletins. It increases by exactly +** one second at the end of each positive UTC leap second, +** introduced in order to keep UT1-UTC within +/- 0.9s. n.b. This +** practice is under review, and in the future UT1-UTC may grow +** essentially without limit. +** +** 4) The geographical coordinates are with respect to the ERFA_WGS84 +** reference ellipsoid. TAKE CARE WITH THE LONGITUDE SIGN: the +** longitude required by the present function is east-positive +** (i.e. right-handed), in accordance with geographical convention. +** +** 5) The polar motion xp,yp can be obtained from IERS bulletins. The +** values are the coordinates (in radians) of the Celestial +** Intermediate Pole with respect to the International Terrestrial +** Reference System (see IERS Conventions 2003), measured along the +** meridians 0 and 90 deg west respectively. For many +** applications, xp and yp can be set to zero. +** +** Internally, the polar motion is stored in a form rotated onto +** the local meridian. +** +** 6) If hm, the height above the ellipsoid of the observing station +** in meters, is not known but phpa, the pressure in hPa (=mB), is +** available, an adequate estimate of hm can be obtained from the +** expression +** +** hm = -29.3 * tsl * log ( phpa / 1013.25 ); +** +** where tsl is the approximate sea-level air temperature in K +** (See Astrophysical Quantities, C.W.Allen, 3rd edition, section +** 52). Similarly, if the pressure phpa is not known, it can be +** estimated from the height of the observing station, hm, as +** follows: +** +** phpa = 1013.25 * exp ( -hm / ( 29.3 * tsl ) ); +** +** Note, however, that the refraction is nearly proportional to +** the pressure and that an accurate phpa value is important for +** precise work. +** +** 7) The argument wl specifies the observing wavelength in +** micrometers. The transition from optical to radio is assumed to +** occur at 100 micrometers (about 3000 GHz). +** +** 8) It is advisable to take great care with units, as even unlikely +** values of the input parameters are accepted and processed in +** accordance with the models used. +** +** 9) In cases where the caller wishes to supply his own Earth +** ephemeris, Earth rotation information and refraction constants, +** the function eraApco can be used instead of the present function. +** +** 10) This is one of several functions that inserts into the astrom +** structure star-independent parameters needed for the chain of +** astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed. +** +** The various functions support different classes of observer and +** portions of the transformation chain: +** +** functions observer transformation +** +** eraApcg eraApcg13 geocentric ICRS <-> GCRS +** eraApci eraApci13 terrestrial ICRS <-> CIRS +** eraApco eraApco13 terrestrial ICRS <-> observed +** eraApcs eraApcs13 space ICRS <-> GCRS +** eraAper eraAper13 terrestrial update Earth rotation +** eraApio eraApio13 terrestrial CIRS <-> observed +** +** Those with names ending in "13" use contemporary ERFA models to +** compute the various ephemerides. The others accept ephemerides +** supplied by the caller. +** +** The transformation from ICRS to GCRS covers space motion, +** parallax, light deflection, and aberration. From GCRS to CIRS +** comprises frame bias and precession-nutation. From CIRS to +** observed takes account of Earth rotation, polar motion, diurnal +** aberration and parallax (unless subsumed into the ICRS <-> GCRS +** transformation), and atmospheric refraction. +** +** 11) The context structure astrom produced by this function is used +** by eraAtioq, eraAtoiq, eraAtciq* and eraAticq*. +** +** Called: +** eraUtctai UTC to TAI +** eraTaitt TAI to TT +** eraUtcut1 UTC to UT1 +** eraEpv00 Earth position and velocity +** eraPnm06a classical NPB matrix, IAU 2006/2000A +** eraBpn2xy extract CIP X,Y coordinates from NPB matrix +** eraS06 the CIO locator s, given X,Y, IAU 2006 +** eraEra00 Earth rotation angle, IAU 2000 +** eraSp00 the TIO locator s', IERS 2000 +** eraRefco refraction constants for given ambient conditions +** eraApco astrometry parameters, ICRS-observed +** eraEors equation of the origins, given NPB matrix and s +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** Derived, with permission, from the SOFA library. See notes at end of file. +*/ +{ + int j; + double tai1, tai2, tt1, tt2, ut11, ut12, ehpv[2][3], ebpv[2][3], + r[3][3], x, y, s, theta, sp, refa, refb; + + +/* UTC to other time scales. */ + j = eraUtctai(utc1, utc2, &tai1, &tai2); + if ( j < 0 ) return -1; + j = eraTaitt(tai1, tai2, &tt1, &tt2); + j = eraUtcut1(utc1, utc2, dut1, &ut11, &ut12); + if ( j < 0 ) return -1; + +/* Earth barycentric & heliocentric position/velocity (au, au/d). */ + (void) eraEpv00(tt1, tt2, ehpv, ebpv); + +/* Form the equinox based BPN matrix, IAU 2006/2000A. */ + eraPnm06a(tt1, tt2, r); + +/* Extract CIP X,Y. */ + eraBpn2xy(r, &x, &y); + +/* Obtain CIO locator s. */ + s = eraS06(tt1, tt2, x, y); + +/* Earth rotation angle. */ + theta = eraEra00(ut11, ut12); + +/* TIO locator s'. */ + sp = eraSp00(tt1, tt2); + +/* Refraction constants A and B. */ + eraRefco(phpa, tc, rh, wl, &refa, &refb); + +/* Compute the star-independent astrometry parameters. */ + eraApco(tt1, tt2, ebpv, ehpv[0], x, y, s, theta, + elong, phi, hm, xp, yp, sp, refa, refb, astrom); + +/* Equation of the origins. */ + *eo = eraEors(r, s); + +/* Return any warning status. */ + return j; + +/* Finished. */ + +} +/*---------------------------------------------------------------------- +** +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** All rights reserved. +** +** This library is derived, with permission, from the International +** Astronomical Union's "Standards of Fundamental Astronomy" library, +** available from http://www.iausofa.org. +** +** The ERFA version is intended to retain identical functionality to +** the SOFA library, but made distinct through different function and +** file names, as set out in the SOFA license conditions. The SOFA +** original has a role as a reference standard for the IAU and IERS, +** and consequently redistribution is permitted only in its unaltered +** state. The ERFA version is not subject to this restriction and +** therefore can be included in distributions which do not support the +** concept of "read only" software. +** +** Although the intent is to replicate the SOFA API (other than +** replacement of prefix names) and results (with the exception of +** bugs; any that are discovered will be fixed), SOFA is not +** responsible for any errors found in this version of the library. +** +** If you wish to acknowledge the SOFA heritage, please acknowledge +** that you are using a library derived from SOFA, rather than SOFA +** itself. +** +** +** TERMS AND CONDITIONS +** +** Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions +** are met: +** +** 1 Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** +** 2 Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** +** 3 Neither the name of the Standards Of Fundamental Astronomy Board, +** the International Astronomical Union nor the names of its +** contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +** POSSIBILITY OF SUCH DAMAGE. +** +*/ |