/* $Procedure ILLUM ( Illumination angles ) */
/* Subroutine */ int illum_(char *target, doublereal *et, char *abcorr, char *
obsrvr, doublereal *spoint, doublereal *phase, doublereal *solar,
doublereal *emissn, ftnlen target_len, ftnlen abcorr_len, ftnlen
obsrvr_len)
{
/* Initialized data */
static logical first = TRUE_;
extern /* Subroutine */ int zzbods2c_(integer *, char *, integer *,
logical *, char *, integer *, logical *, ftnlen, ftnlen);
extern doublereal vsep_(doublereal *, doublereal *);
extern /* Subroutine */ int vsub_(doublereal *, doublereal *, doublereal *
), vequ_(doublereal *, doublereal *), zzctruin_(integer *);
integer n;
doublereal radii[3];
extern /* Subroutine */ int chkin_(char *, ftnlen), errch_(char *, char *,
ftnlen, ftnlen);
logical found;
extern /* Subroutine */ int spkez_(integer *, doublereal *, char *, char *
, integer *, doublereal *, doublereal *, ftnlen, ftnlen);
extern logical eqstr_(char *, char *, ftnlen, ftnlen);
static logical svfnd1, svfnd2;
static integer svctr1[2], svctr2[2];
integer obscde;
doublereal lt;
extern /* Subroutine */ int bodvcd_(integer *, char *, integer *, integer
*, doublereal *, ftnlen);
integer frcode;
extern /* Subroutine */ int cidfrm_(integer *, integer *, char *, logical
*, ftnlen);
char frname[80];
integer trgcde;
doublereal offobs[3], obsvec[3], tepoch, normal[3];
static integer svtcde;
extern /* Subroutine */ int sigerr_(char *, ftnlen), chkout_(char *,
ftnlen);
static integer svobsc;
doublereal offsun[3];
extern /* Subroutine */ int setmsg_(char *, ftnlen);
doublereal sstate[6], sunvec[3], tstate[6];
static char svtarg[36];
extern /* Subroutine */ int surfnm_(doublereal *, doublereal *,
doublereal *, doublereal *, doublereal *);
extern logical return_(void);
static char svobsr[36];
extern /* Subroutine */ int vminus_(doublereal *, doublereal *);
doublereal lts;
/* $ Abstract */
/* Deprecated: This routine has been superseded by the SPICELIB */
/* routine ILUMIN. This routine is supported for purposes of */
/* backward compatibility only. */
/* Find the illumination angles at a specified surface point of a */
/* target body. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Required_Reading */
/* KERNEL */
/* NAIF_IDS */
/* SPK */
/* TIME */
/* $ Keywords */
/* GEOMETRY */
/* MOSPICE */
/* $ Declarations */
/* $ Abstract */
/* This include file defines the dimension of the counter */
/* array used by various SPICE subsystems to uniquely identify */
/* changes in their states. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Parameters */
/* CTRSIZ is the dimension of the counter array used by */
/* various SPICE subsystems to uniquely identify */
/* changes in their states. */
/* $ Author_and_Institution */
/* B.V. Semenov (JPL) */
/* $ Literature_References */
/* None. */
/* $ Version */
/* - SPICELIB Version 1.0.0, 29-JUL-2013 (BVS) */
/* -& */
/* End of include file. */
/* $ Brief_I/O */
/* Variable I/O Description */
/* -------- --- -------------------------------------------------- */
/* TARGET I Name of target body. */
/* ET I Epoch in ephemeris seconds past J2000. */
/* ABCORR I Desired aberration correction. */
/* OBSRVR I Name of observing body. */
/* SPOINT I Body-fixed coordinates of a target surface point. */
/* PHASE O Phase angle at the surface point. */
/* SOLAR O Solar incidence angle at the surface point. */
/* EMISSN O Emission angle at the surface point. */
/* $ Detailed_Input */
/* TARGET is the name of the target body. TARGET is */
/* case-insensitive, and leading and trailing blanks */
/* in TARGET are not significant. Optionally, you may */
/* supply a string containing the integer ID code for */
/* the object. For example both 'MOON' and '301' are */
/* legitimate strings that indicate the moon is the */
/* target body. */
/* ET is the epoch, specified in ephemeris seconds past */
/* J2000, at which the apparent illumination angles at */
/* the specified surface point on the target body, as */
/* seen from the observing body, are to be computed. */
/* ABCORR is the aberration correction to be used in */
/* computing the location and orientation of the */
/* target body and the location of the Sun. Possible */
/* values are: */
/* 'NONE' No aberration correction. */
/* 'LT' Correct the position and */
/* orientation of target body for */
/* light time, and correct the */
/* position of the Sun for light */
/* time. */
/* 'LT+S' Correct the observer-target vector */
/* for light time and stellar */
/* aberration, correct the */
/* orientation of the target body */
/* for light time, and correct the */
/* target-Sun vector for light time */
/* and stellar aberration. */
/* 'CN' Converged Newtonian light time */
/* correction. In solving the light */
/* time equation, the 'CN' */
/* correction iterates until the */
/* solution converges (three */
/* iterations on all supported */
/* platforms). Whether the 'CN+S' */
/* solution is substantially more */
/* accurate than the 'LT' solution */
/* depends on the geometry of the */
/* participating objects and on the */
/* accuracy of the input data. In */
/* all cases this routine will */
/* execute more slowly when a */
/* converged solution is computed. */
/* See the Particulars section of */
/* SPKEZR for a discussion of */
/* precision of light time */
/* corrections. */
/* Both the state and rotation of */
/* the target body are corrected for */
/* light time. */
/* 'CN+S' Converged Newtonian light time */
/* correction and stellar aberration */
/* correction. */
/* Both the state and rotation of */
/* the target body are corrected for */
/* light time. */
/* OBSRVR is the name of the observing body, typically a */
/* spacecraft, the earth, or a surface point on the */
/* earth. OBSRVR is case-insensitive, and leading */
/* and trailing blanks in OBSRVR are not significant. */
/* Optionally, you may supply a string containing the */
/* integer ID code for the object. For example both */
/* 'EARTH' and '399' are legitimate strings that */
/* indicate the earth is the observer. */
/* OBSRVR may be not be identical to TARGET. */
/* SPOINT is a surface point on the target body, expressed */
/* in rectangular body-fixed (body equator and prime */
/* meridian) coordinates. SPOINT need not be visible */
/* from the observer's location at time ET. */
/* $ Detailed_Output */
/* PHASE is the phase angle at SPOINT, as seen from OBSRVR */
/* at time ET. This is the angle between the */
/* SPOINT-OBSRVR vector and the SPOINT-Sun vector. */
/* Units are radians. The range of PHASE is [0, pi]. */
/* See Particulars below for a detailed discussion of */
/* the definition. */
/* SOLAR is the solar incidence angle at SPOINT, as seen */
/* from OBSRVR at time ET. This is the angle */
/* between the surface normal vector at SPOINT and the */
/* SPOINT-Sun vector. Units are radians. The range */
/* of SOLAR is [0, pi]. See Particulars below for a */
/* detailed discussion of the definition. */
/* EMISSN is the emission angle at SPOINT, as seen from */
/* OBSRVR at time ET. This is the angle between the */
/* surface normal vector at SPOINT and the */
/* SPOINT-observer vector. Units are radians. The */
/* range of EMISSN is [0, pi]. See Particulars below */
/* for a detailed discussion of the definition. */
/* $ Parameters */
/* None. */
/* $ Exceptions */
/* 1) If TARGET and OBSRVR are not distinct, the error */
/* SPICE(BODIESNOTDISTINCT) will be signaled. */
/* 2) If no SPK (ephemeris) data are available for the observer, */
/* target, and Sun at the time specified by ET, the error will */
/* be diagnosed by routines called by this routine. If light */
/* time corrections are used, SPK data for the target body must */
/* be available at the time ET - LT, where LT is the one-way */
/* light time from the target to the observer at ET. */
/* Additionally, SPK data must be available for the Sun at the */
/* time ET - LT - LT2, where LT2 is the light time from the Sun */
/* to the target body at time ET - LT. */
/* 3) If PCK data defining the orientation or shape of the target */
/* body are unavailable, the error will be diagnosed by routines */
/* called by this routine. */
/* 4) If no body-fixed frame is associated with the target body, */
/* the error SPICE(NOFRAME) is signaled. */
/* 5) If name of target or observer cannot be translated to its */
/* NAIF ID code, the error SPICE(IDCODENOTFOUND) is signaled. */
/* $ Files */
/* No files are input to this routine. However, ILLUM expects */
/* that the appropriate SPK and PCK files have been loaded via */
/* FURNSH. */
/* $ Particulars */
/* The term "illumination angles" refers to following set of */
/* angles: */
/* solar incidence angle Angle between the surface normal at */
/* the specified surface point and the */
/* vector from the surface point to the */
/* Sun. */
/* emission angle Angle between the surface normal at */
/* the specified surface point and the */
/* vector from the surface point to the */
/* observer. */
/* phase angle Angle between the vectors from the */
/* surface point to the observing body's */
/* location and from the surface point */
/* to the Sun. */
/* The diagram below illustrates the geometrical relationships */
/* defining these angles. The labels for the solar incidence, */
/* emission, and phase angles are "s.i.", "e.", and "phase". */
/* * */
/* Sun */
/* surface normal vector */
/* ._ _. */
/* |\ /| Sun vector */
/* \ phase / */
/* \ . . / */
/* . . */
/* \ ___ / */
/* . \/ \/ */
/* _\ s.i./ */
/* . / \ / */
/* . | e. \ / */
/* * <--------------- * surface point on */
/* viewing vector target body */
/* location to viewing */
/* (observer) location */
/* Note that if the target-observer vector, the target normal vector */
/* at the surface point, and the target-sun vector are coplanar, */
/* then phase is the sum of incidence and emission. This is rarely */
/* true; usually */
/* phase angle < solar incidence angle + emission angle */
/* All of the above angles can be computed using light time */
/* corrections, light time and stellar aberration corrections, or */
/* no aberration corrections. The way aberration corrections */
/* are used is described below. */
/* Care must be used in computing light time corrections. The */
/* guiding principle used here is "describe what appears in */
/* an image." We ignore differential light time; the light times */
/* from all points on the target to the observer are presumed to be */
/* equal. */
/* Observer-target body vector */
/* --------------------------- */
/* Let ET be the epoch at which an observation or remote */
/* sensing measurement is made, and let ET - LT ("LT" stands */
/* for "light time") be the epoch at which the photons received */
/* at ET were emitted from the body (we use the term "emitted" */
/* loosely here). */
/* The correct observer-target vector points from the observer's */
/* location at ET to the target body's location at ET - LT. */
/* The target-observer vector points in the opposite direction. */
/* Since light time corrections are not symmetric, the correct */
/* target-observer vector CANNOT be found by computing the light */
/* time corrected position of the observer as seen from the */
/* target body. */
/* Target body's orientation */
/* ------------------------- */
/* Using the definitions of ET and LT above, the target */
/* body's orientation at ET - LT is used. The surface */
/* normal is dependent on the target body's orientation, so */
/* the body's orientation model must be evaluated for the correct */
/* epoch. */
/* Target body -- Sun vector */
/* ------------------------- */
/* All surface features on the target body will appear in */
/* a measurement made at ET as they were at ET-LT. In */
/* particular, lighting on the target body is dependent on */
/* the apparent location of the Sun as seen from the target */
/* body at ET-LT. So, a second light time correction is used */
/* in finding the apparent location of the Sun. */
/* Stellar aberration corrections, when used, are applied as follows: */
/* Observer-target body vector */
/* --------------------------- */
/* In addition to light time correction, stellar aberration is */
/* used in computing the apparent target body position as seen */
/* from the observer's location at time ET. This apparent */
/* position defines the observer-target body vector. */
/* Target body-Sun vector */
/* ---------------------- */
/* The target body-Sun vector is the apparent position of the Sun, */
/* corrected for light time and stellar aberration, as seen from */
/* the target body at time ET-LT. Note that the target body's */
/* position is not affected by the stellar aberration correction */
/* applied in finding its apparent position as seen by the */
/* observer. */
/* Once all of the vectors, as well as the target body's */
/* orientation, have been computed with the proper aberration */
/* corrections, the element of time is eliminated from the */
/* computation. The problem becomes a purely geometrical one, */
/* and is described by the diagram above. */
/* $ Examples */
/* The numerical results shown for this example may differ across */
/* platforms. The results depend on the SPICE kernels used as */
/* input, the compiler and supporting libraries, and the machine */
/* specific arithmetic implementation. */
/* In the following example program, the file */
/* spk_m_031103-040201_030502.bsp */
/* is a binary SPK file containing data for Mars Global Surveyor, */
/* Mars, and the Sun for a time interval bracketing the date */
/* 2004 JAN 1 12:00:00 UTC. */
/* pck00007.tpc is a planetary constants kernel file containing */
/* radii and rotation model constants. naif0007.tls is a */
/* leapseconds kernel. */
/* Find the phase, solar incidence, and emission angles at the */
/* sub-solar and sub-spacecraft points on Mars as seen from the */
/* Mars Global Surveyor spacecraft at a specified UTC time. */
/* Use light time and stellar aberration corrections. */
/* PROGRAM ANGLES */
/* IMPLICIT NONE */
/* C */
/* C SPICELIB functions */
/* C */
/* DOUBLE PRECISION DPR */
/* C */
/* C Local parameters */
/* C */
/* INTEGER NAMLEN */
/* PARAMETER ( NAMLEN = 32 ) */
/* INTEGER TIMLEN */
/* PARAMETER ( TIMLEN = 25 ) */
/* C */
/* C Local variables */
/* C */
/* CHARACTER*(NAMLEN) OBSRVR */
/* CHARACTER*(NAMLEN) TARGET */
/* CHARACTER*(TIMLEN) UTC */
/* DOUBLE PRECISION ALT */
/* DOUBLE PRECISION ET */
/* DOUBLE PRECISION SSCEMI */
/* DOUBLE PRECISION SSCPHS */
/* DOUBLE PRECISION SSCSOL */
/* DOUBLE PRECISION SSLEMI */
/* DOUBLE PRECISION SSLPHS */
/* DOUBLE PRECISION SSLSOL */
/* DOUBLE PRECISION SSOLPT ( 3 ) */
/* DOUBLE PRECISION SSCPT ( 3 ) */
/* C */
/* C Load kernel files. */
/* C */
/* CALL FURNSH ( 'naif0007.tls' ) */
/* CALL FURNSH ( 'pck00007.tpc' ) */
/* CALL FURNSH ( 'spk_m_031103-040201_030502.bsp' ) */
/* C */
/* C Convert our UTC time to ephemeris seconds past J2000. */
/* C */
/* UTC = '2004 JAN 1 12:00:00' */
/* CALL UTC2ET ( UTC, ET ) */
/* C */
/* C Assign observer and target names. The acronym MGS */
/* C indicates Mars Global Surveyor. See NAIF_IDS for a */
/* C list of names recognized by SPICE. */
/* C */
/* TARGET = 'Mars' */
/* OBSRVR = 'MGS' */
/* C */
/* C Find the sub-solar point on the Earth as seen from */
/* C the MGS spacecraft at ET. Use the "surface intercept" */
/* C style of sub-point definition. This makes it easy */
/* C to verify the solar incidence angle. */
/* C */
/* CALL SUBSOL ( 'Near point', TARGET, ET, */
/* . 'LT+S', OBSRVR, SSOLPT ) */
/* C */
/* C Now find the sub-spacecraft point. Use the */
/* C "nearest point" definition of the sub-point */
/* C here---this makes it easy to verify the emission angle. */
/* C */
/* CALL SUBPT ( 'Near point', TARGET, ET, */
/* . 'LT+S', OBSRVR, SSCPT, ALT ) */
/* C */
/* C Find the phase, solar incidence, and emission */
/* C angles at the sub-solar point on the Earth as seen */
/* C from Mars Observer at time ET. */
/* C */
/* CALL ILLUM ( TARGET, ET, 'LT+S', OBSRVR, */
/* . SSOLPT, SSLPHS, SSLSOL, SSLEMI ) */
/* C */
/* C Do the same for the sub-spacecraft point. */
/* C */
/* CALL ILLUM ( TARGET, ET, 'LT+S', OBSRVR, */
/* . SSCPT, SSCPHS, SSCSOL, SSCEMI ) */
/* C */
/* C Convert the angles to degrees and write them out. */
/* C */
/* SSLPHS = DPR() * SSLPHS */
/* SSLSOL = DPR() * SSLSOL */
/* SSLEMI = DPR() * SSLEMI */
/* SSCPHS = DPR() * SSCPHS */
/* SSCSOL = DPR() * SSCSOL */
/* SSCEMI = DPR() * SSCEMI */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'UTC epoch is ', UTC */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'Illumination angles at the sub-solar point:' */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'Phase angle (deg.): ', SSLPHS */
/* WRITE (*,*) 'Solar incidence angle (deg.): ', SSLSOL */
/* WRITE (*,*) 'Emission angle (deg.): ', SSLEMI */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'The solar incidence angle should be 0.' */
/* WRITE (*,*) 'The emission and phase angles should be equal.' */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'Illumination angles at the sub-s/c point:' */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'Phase angle (deg.): ', SSCPHS */
/* WRITE (*,*) 'Solar incidence angle (deg.): ', SSCSOL */
/* WRITE (*,*) 'Emission angle (deg.): ', SSCEMI */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'The emission angle should be 0.' */
/* WRITE (*,*) 'The solar incidence and phase angles should '// */
/* . 'be equal.' */
/* END */
/* When this program is executed, the output will be: */
/* UTC epoch is 2004 JAN 1 12:00:00 */
/* Illumination angles at the sub-solar point: */
/* Phase angle (deg.): 150.210714 */
/* Solar incidence angle (deg.): 6.3735213E-15 */
/* Emission angle (deg.): 150.210714 */
/* The solar incidence angle should be 0. */
/* The emission and phase angles should be equal. */
/* Illumination angles at the sub-s/c point: */
/* Phase angle (deg.): 123.398202 */
/* Solar incidence angle (deg.): 123.398202 */
/* Emission angle (deg.): 6.36110936E-15 */
/* The emission angle should be 0. */
/* The solar incidence and phase angles should be equal. */
/* $ Restrictions */
/* None. */
/* $ Literature_References */
/* None. */
/* $ Author_and_Institution */
/* C.H. Acton (JPL) */
/* B.V. Semenov (JPL) */
/* N.J. Bachman (JPL) */
/* $ Version */
/* - SPICELIB Version 1.3.0, 04-JUL-2014 (NJB) (BVS) */
/* Discussion of light time corrections was updated. Assertions */
/* that converged light time corrections are unlikely to be */
/* useful were removed. */
/* Last update was 19-SEP-2013 (BVS) */
/* Updated to save the input body names and ZZBODTRN state */
/* counters and to do name-ID conversions only if the counters */
/* have changed. */
/* - SPICELIB Version 1.2.2, 18-MAY-2010 (BVS) */
/* Index lines now state that this routine is deprecated. */
/* - SPICELIB Version 1.2.1, 07-FEB-2008 (NJB) */
/* Abstract now states that this routine is deprecated. */
/* - SPICELIB Version 1.2.0, 23-OCT-2005 (NJB) */
/* Updated to remove non-standard use of duplicate arguments */
/* in VSUB calls. Replaced call to BODVAR with call to BODVCD. */
/* - SPICELIB Version 1.1.0, 22-JUL-2004 (NJB) */
/* Updated to support representations of integers in the input */
/* arguments TARGET and OBSRVR. */
/* - SPICELIB Version 1.0.2, 27-JUL-2003 (NJB) (CHA) */
/* Various header corrections were made. The example program */
/* was upgraded to use real kernels, and the program's output is */
/* shown. */
/* - SPICELIB Version 1.0.1, 10-JUL-2002 (NJB) */
/* Updated Index_Entries header section. */
/* - SPICELIB Version 1.0.0, 21-MAR-1999 (NJB) */
/* Adapted from the MGSSPICE version dated 10-MAR-1992. */
/* -& */
/* $ Index_Entries */
/* DEPRECATED illumination angles */
/* DEPRECATED lighting angles */
/* DEPRECATED phase angle */
/* DEPRECATED solar incidence angle */
/* DEPRECATED emission angle */
/* -& */
/* $ Revisions */
/* - SPICELIB Version 1.2.0, 23-OCT-2005 (NJB) */
/* Updated to remove non-standard use of duplicate arguments */
/* in VSUB calls. Replaced call to BODVAR with call to BODVCD. */
/* - SPICELIB Version 1.1.0, 22-JUL-2004 (NJB) */
/* Updated to support representations of integers in the */
/* input arguments TARGET and OBSRVR: calls to BODN2C */
/* were replaced by calls to BODS2C. */
/* -& */
/* SPICELIB functions */
/* Local parameters */
/* Saved body name length. */
/* Local variables */
/* Saved name/ID item declarations. */
/* Saved name/ID items. */
/* Initial values. */
/* Standard SPICE error handling. */
if (return_()) {
return 0;
} else {
chkin_("ILLUM", (ftnlen)5);
}
/* Initialization. */
if (first) {
/* Initialize counters. */
zzctruin_(svctr1);
zzctruin_(svctr2);
first = FALSE_;
}
/* Obtain integer codes for the target and observer. */
zzbods2c_(svctr1, svtarg, &svtcde, &svfnd1, target, &trgcde, &found, (
ftnlen)36, target_len);
if (! found) {
setmsg_("The target, '#', is not a recognized name for an ephemeris "
"object. The cause of this problem may be that you need an up"
"dated version of the SPICE Toolkit. ", (ftnlen)155);
errch_("#", target, (ftnlen)1, target_len);
sigerr_("SPICE(IDCODENOTFOUND)", (ftnlen)21);
chkout_("ILLUM", (ftnlen)5);
return 0;
}
zzbods2c_(svctr2, svobsr, &svobsc, &svfnd2, obsrvr, &obscde, &found, (
ftnlen)36, obsrvr_len);
if (! found) {
setmsg_("The observer, '#', is not a recognized name for an ephemeri"
"s object. The cause of this problem may be that you need an "
"updated version of the SPICE Toolkit. ", (ftnlen)157);
errch_("#", obsrvr, (ftnlen)1, obsrvr_len);
sigerr_("SPICE(IDCODENOTFOUND)", (ftnlen)21);
chkout_("ILLUM", (ftnlen)5);
return 0;
}
/* The observer and target must be distinct. */
if (trgcde == obscde) {
setmsg_("Target is #; observer is #.", (ftnlen)27);
errch_("#", target, (ftnlen)1, target_len);
errch_("#", obsrvr, (ftnlen)1, obsrvr_len);
sigerr_("SPICE(BODIESNOTDISTINCT)", (ftnlen)24);
chkout_("ILLUM", (ftnlen)5);
return 0;
}
/* Find the name of the body-fixed frame associated with the */
/* target body. We'll want the state of the target relative to */
/* the observer in this body-fixed frame. */
cidfrm_(&trgcde, &frcode, frname, &found, (ftnlen)80);
if (! found) {
setmsg_("No body-fixed frame is associated with target body #; a fra"
"me kernel must be loaded to make this association. Consult "
"the FRAMES Required Reading for details.", (ftnlen)159);
errch_("#", target, (ftnlen)1, target_len);
sigerr_("SPICE(NOFRAME)", (ftnlen)14);
chkout_("ILLUM", (ftnlen)5);
return 0;
}
/* Find the body-fixed state of the target as seen from the observer */
/* at ET. The appropriate aberration corrections will be used in */
/* evaluating this state. */
spkez_(&trgcde, et, frname, abcorr, &obscde, tstate, <, (ftnlen)80,
abcorr_len);
/* Determine the epoch to be used in computing the target-Sun vector. */
if (eqstr_(abcorr, "NONE", abcorr_len, (ftnlen)4)) {
tepoch = *et;
} else {
tepoch = *et - lt;
}
/* Find the body-fixed state of the Sun as seen from the target at */
/* TEPOCH. */
spkez_(&c__10, &tepoch, frname, abcorr, &trgcde, sstate, <s, (ftnlen)80,
abcorr_len);
/* Grab the position portions of the states (the first three */
/* elements of each state). Negate the observer-target vector, */
/* since the vector required for the illumination angle */
/* computation is the target-observer vector. The vectors we've */
/* found point from the target body center to the observer and */
/* Sun, and already take light time corrections into account. */
vminus_(tstate, obsvec);
vequ_(sstate, sunvec);
/* Now we'll modify target-observer and target-Sun vectors to */
/* take into account the offset between the target center and the */
/* surface point of interest; we want the vectors to point from */
/* the surface point to the observer and Sun respectively. */
vsub_(obsvec, spoint, offobs);
vsub_(sunvec, spoint, offsun);
/* Find the surface normal at SPOINT. We'll need the radii of the */
/* target body. */
bodvcd_(&trgcde, "RADII", &c__3, &n, radii, (ftnlen)5);
surfnm_(radii, &radii[1], &radii[2], spoint, normal);
/* Find the illumination angles. VSEP will give us angular */
/* separation in radians. */
*phase = vsep_(offsun, offobs);
*solar = vsep_(normal, offsun);
*emissn = vsep_(normal, offobs);
chkout_("ILLUM", (ftnlen)5);
return 0;
} /* illum_ */
/* $Procedure SUBSOL ( Sub-solar point ) */
/* Subroutine */ int subsol_(char *method, char *target, doublereal *et, char
*abcorr, char *obsrvr, doublereal *spoint, ftnlen method_len, ftnlen
target_len, ftnlen abcorr_len, ftnlen obsrvr_len)
{
/* Initialized data */
static doublereal origin[3] = { 0.,0.,0. };
doublereal radii[3];
extern /* Subroutine */ int chkin_(char *, ftnlen), errch_(char *, char *,
ftnlen, ftnlen), ltime_(doublereal *, integer *, char *, integer
*, doublereal *, doublereal *, ftnlen);
logical found;
extern logical eqstr_(char *, char *, ftnlen, ftnlen);
doublereal sunlt;
extern /* Subroutine */ int bods2c_(char *, integer *, logical *, ftnlen);
integer obscde;
doublereal lt;
extern /* Subroutine */ int bodvcd_(integer *, char *, integer *, integer
*, doublereal *, ftnlen);
integer frcode;
extern /* Subroutine */ int cidfrm_(integer *, integer *, char *, logical
*, ftnlen);
integer nradii;
char frname[80];
integer trgcde;
doublereal ettarg;
extern /* Subroutine */ int nearpt_(doublereal *, doublereal *,
doublereal *, doublereal *, doublereal *, doublereal *), sigerr_(
char *, ftnlen), chkout_(char *, ftnlen), setmsg_(char *, ftnlen);
extern logical return_(void);
extern /* Subroutine */ int spkpos_(char *, doublereal *, char *, char *,
char *, doublereal *, doublereal *, ftnlen, ftnlen, ftnlen,
ftnlen), surfpt_(doublereal *, doublereal *, doublereal *,
doublereal *, doublereal *, doublereal *, logical *);
doublereal alt, pos[3];
/* $ Abstract */
/* Deprecated: This routine has been superseded by the SPICELIB */
/* routine SUBSLR. This routine is supported for purposes of */
/* backward compatibility only. */
/* Determine the coordinates of the sub-solar point on a target */
/* body as seen by a specified observer at a specified epoch, */
/* optionally corrected for planetary (light time) and stellar */
/* aberration. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Required_Reading */
/* FRAMES */
/* PCK */
/* SPK */
/* TIME */
/* $ Keywords */
/* GEOMETRY */
/* $ Declarations */
/* $ Brief_I/O */
/* Variable I/O Description */
/* -------- --- -------------------------------------------------- */
/* METHOD I Computation method. */
/* TARGET I Name of target body. */
/* ET I Epoch in ephemeris seconds past J2000 TDB. */
/* ABCORR I Aberration correction. */
/* OBSRVR I Name of observing body. */
/* SPOINT O Sub-solar point on the target body. */
/* $ Detailed_Input */
/* METHOD is a short string specifying the computation method */
/* to be used. The choices are: */
/* 'Near point' The sub-solar point is defined */
/* as the nearest point on the */
/* target to the sun. */
/* 'Intercept' The sub-observer point is */
/* defined as the target surface */
/* intercept of the line */
/* containing the target's center */
/* and the sun's center. */
/* In both cases, the intercept computation treats the */
/* surface of the target body as a triaxial ellipsoid. */
/* The ellipsoid's radii must be available in the kernel */
/* pool. */
/* Neither case nor white space are significant in */
/* METHOD. For example, the string ' NEARPOINT' is */
/* valid. */
/* TARGET is the name of the target body. TARGET is */
/* case-insensitive, and leading and trailing blanks in */
/* TARGET are not significant. Optionally, you may */
/* supply a string containing the integer ID code for */
/* the object. For example both 'MOON' and '301' are */
/* legitimate strings that indicate the moon is the */
/* target body. */
/* This routine assumes that the target body is modeled */
/* by a tri-axial ellipsoid, and that a PCK file */
/* containing its radii has been loaded into the kernel */
/* pool via FURNSH. */
/* ET is the epoch in ephemeris seconds past J2000 at which */
/* the sub-solar point on the target body is to be */
/* computed. */
/* ABCORR indicates the aberration corrections to be applied */
/* when computing the observer-target state. ABCORR */
/* may be any of the following. */
/* 'NONE' Apply no correction. Return the */
/* geometric sub-solar point on the target */
/* body. */
/* 'LT' Correct for planetary (light time) */
/* aberration. Both the state and rotation */
/* of the target body are corrected for one */
/* way light time from target to observer. */
/* The state of the sun relative to the */
/* target is corrected for one way light */
/* from the sun to the target; this state */
/* is evaluated at the epoch obtained by */
/* retarding ET by the one way light time */
/* from target to observer. */
/* 'LT+S' Correct for planetary (light time) and */
/* stellar aberrations. Light time */
/* corrections are the same as in the 'LT' */
/* case above. The target state is */
/* additionally corrected for stellar */
/* aberration as seen by the observer, and */
/* the sun state is corrected for stellar */
/* aberration as seen from the target. */
/* 'CN' Converged Newtonian light time */
/* corrections. This is the same as LT */
/* corrections but with further iterations */
/* to a converged Newtonian light time */
/* solution. Given that relativistic */
/* effects may be as large as the higher */
/* accuracy achieved by this computation, */
/* this is correction is seldom worth the */
/* additional computations required unless */
/* the user incorporates additional */
/* relativistic corrections. Light */
/* time corrections are applied as in the */
/* 'LT' case. */
/* 'CN+S' Converged Newtonian light time */
/* corrections and stellar aberration. */
/* Light time and stellar aberration */
/* corrections are applied as in the */
/* 'LT+S' case. */
/* OBSRVR is the name of the observing body, typically a */
/* spacecraft, the earth, or a surface point on the */
/* earth. OBSRVR is case-insensitive, and leading and */
/* trailing blanks in OBSRVR are not significant. */
/* Optionally, you may supply a string containing the */
/* integer ID code for the object. For example both */
/* 'EARTH' and '399' are legitimate strings that indicate */
/* the earth is the observer. */
/* $ Detailed_Output */
/* SPOINT is the sub-solar point on the target body at ET */
/* expressed relative to the body-fixed frame of the */
/* target body. */
/* The sub-solar point is defined either as the point on */
/* the target body that is closest to the sun, or the */
/* target surface intercept of the line containing the */
/* target's center and the sun's center; the input */
/* argument METHOD selects the definition to be used. */
/* The body-fixed frame, which is time-dependent, is */
/* evaluated at ET if ABCORR is 'NONE'; otherwise the */
/* frame is evaluated at ET-LT, where LT is the one way */
/* light time from target to observer. */
/* The state of the target body is corrected for */
/* aberration as specified by ABCORR; the corrected */
/* state is used in the geometric computation. As */
/* indicated above, the rotation of the target is */
/* retarded by one way light time if ABCORR specifies */
/* that light time correction is to be done. */
/* The state of the sun as seen from the observing */
/* body is also corrected for aberration as specified */
/* by ABCORR. The corrections, when selected, are */
/* applied at the epoch ET-LT, where LT is the one way */
/* light time from target to observer. */
/* $ Parameters */
/* None. */
/* $ Exceptions */
/* If any of the listed errors occur, the output arguments are */
/* left unchanged. */
/* 1) If the input argument METHOD is not recognized, the error */
/* SPICE(DUBIOUSMETHOD) is signaled. */
/* 2) If either of the input body names TARGET or OBSRVR cannot be */
/* mapped to NAIF integer codes, the error SPICE(IDCODENOTFOUND) */
/* is signaled. */
/* 3) If OBSRVR and TARGET map to the same NAIF integer ID codes, the */
/* error SPICE(BODIESNOTDISTINCT) is signaled. */
/* 4) If frame definition data enabling the evaluation of the state */
/* of the target relative to the observer in target body-fixed */
/* coordinates have not been loaded prior to calling SUBSOL, the */
/* error will be diagnosed and signaled by a routine in the call */
/* tree of this routine. */
/* 5) If the specified aberration correction is not recognized, the */
/* error will be diagnosed and signaled by a routine in the call */
/* tree of this routine. */
/* 6) If insufficient ephemeris data have been loaded prior to */
/* calling SUBSOL, the error will be diagnosed and signaled by a */
/* routine in the call tree of this routine. */
/* 7) If the triaxial radii of the target body have not been loaded */
/* into the kernel pool prior to calling SUBSOL, the error will be */
/* diagnosed and signaled by a routine in the call tree of this */
/* routine. */
/* 8) The target must be an extended body: if any of the radii of */
/* the target body are non-positive, the error will be diagnosed */
/* and signaled by routines in the call tree of this routine. */
/* 9) If PCK data supplying a rotation model for the target body */
/* have not been loaded prior to calling SUBSOL, the error will be */
/* diagnosed and signaled by a routine in the call tree of this */
/* routine. */
/* $ Files */
/* Appropriate SPK, PCK, and frame data must be available to */
/* the calling program before this routine is called. Typically */
/* the data are made available by loading kernels; however the */
/* data may be supplied via subroutine interfaces if applicable. */
/* The following data are required: */
/* - SPK data: ephemeris data for sun, target, and observer must */
/* be loaded. If aberration corrections are used, the states of */
/* sun, target, and observer relative to the solar system */
/* barycenter must be calculable from the available ephemeris */
/* data. Ephemeris data are made available by loading */
/* one or more SPK files via FURNSH. */
/* - PCK data: triaxial radii for the target body must be loaded */
/* into the kernel pool. Typically this is done by loading a */
/* text PCK file via FURNSH. */
/* - Further PCK data: a rotation model for the target body must */
/* be loaded. This may be provided in a text or binary PCK */
/* file which is loaded via FURNSH. */
/* - Frame data: if a frame definition is required to convert */
/* the sun, observer, and target states to the body-fixed frame */
/* of the target, that definition must be available in the */
/* kernel pool. Typically the definition is supplied by loading */
/* a frame kernel via FURNSH. */
/* In all cases, kernel data are normally loaded once per program */
/* run, NOT every time this routine is called. */
/* $ Particulars */
/* SUBSOL computes the sub-solar point on a target body, as seen by */
/* a specified observer. */
/* There are two different popular ways to define the sub-solar */
/* point: "nearest point on target to the sun" or "target surface */
/* intercept of line containing target and sun." These coincide */
/* when the target is spherical and generally are distinct otherwise. */
/* When comparing sub-point computations with results from sources */
/* other than SPICE, it's essential to make sure the same geometric */
/* definitions are used. */
/* $ Examples */
/* In the following example program, the file MGS.BSP is a */
/* hypothetical binary SPK ephemeris file containing data for the */
/* Mars Global Surveyor orbiter. The SPK file de405s.bsp contains */
/* data for the planet barycenters as well as the Earth, Moon, and */
/* Sun for the time period including the date 1997 Dec 31 12:000 */
/* UTC. MGS0000A.TPC is a planetary constants kernel file */
/* containing radii and rotation model constants. MGS00001.TLS is */
/* a leapseconds file. (File names shown here that are specific */
/* to MGS are not names of actual files.) */
/* IMPLICIT NONE */
/* CHARACTER*25 METHOD ( 2 ) */
/* INTEGER I */
/* DOUBLE PRECISION DPR */
/* DOUBLE PRECISION ET */
/* DOUBLE PRECISION LAT */
/* DOUBLE PRECISION LON */
/* DOUBLE PRECISION RADIUS */
/* DOUBLE PRECISION SPOINT ( 3 ) */
/* DATA METHOD / 'Intercept', 'Near point' / */
/* C */
/* C Load kernel files. */
/* C */
/* CALL FURNSH ( 'MGS00001.TLS' ) */
/* CALL FURNSH ( 'MGS0000A.TPC' ) */
/* CALL FURNSH ( 'de405s.bsp' ) */
/* CALL FURNSH ( 'MGS.BSP' ) */
/* C */
/* C Convert the UTC request time to ET (seconds past */
/* C J2000, TDB). */
/* C */
/* CALL STR2ET ( '1997 Dec 31 12:00:00', ET ) */
/* C */
/* C Compute sub-spacecraft point using light time and stellar */
/* C aberration corrections. Use the "target surface intercept" */
/* C definition of sub-spacecraft point on the first loop */
/* C iteration, and use the "near point" definition on the */
/* C second. */
/* C */
/* DO I = 1, 2 */
/* CALL SUBSOL ( METHOD(I), */
/* . 'MARS', ET, 'LT+S', 'MGS', SPOINT ) */
/* C */
/* C Convert rectangular coordinates to planetocentric */
/* C latitude and longitude. Convert radians to degrees. */
/* C */
/* CALL RECLAT ( SPOINT, RADIUS, LON, LAT ) */
/* LON = LON * DPR () */
/* LAT = LAT * DPR () */
/* C */
/* C Write the results. */
/* C */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'Computation method: ', METHOD(I) */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) ' Radius (km) = ', RADIUS */
/* WRITE (*,*) ' Planetocentric Latitude (deg) = ', LAT */
/* WRITE (*,*) ' Planetocentric Longitude (deg) = ', LON */
/* WRITE (*,*) ' ' */
/* END DO */
/* END */
/* $ Restrictions */
/* The appropriate kernel data must have been loaded before this */
/* routine is called. See the Files section above. */
/* $ Literature_References */
/* None. */
/* $ Author_and_Institution */
/* N.J. Bachman (JPL) */
/* J.E. McLean (JPL) */
/* $ Version */
/* - SPICELIB Version 1.2.3, 18-MAY-2010 (BVS) */
/* Index line now states that this routine is deprecated. */
/* - SPICELIB Version 1.2.2, 17-MAR-2009 (EDW) */
/* Typo correction in Required_Reading, changed */
/* FRAME to FRAMES. */
/* - SPICELIB Version 1.2.1, 07-FEB-2008 (NJB) */
/* Abstract now states that this routine is deprecated. */
/* - SPICELIB Version 1.2.0, 24-OCT-2005 (NJB) */
/* Call to BODVAR was replaced with call to BODVCD. */
/* - SPICELIB Version 1.1.0, 22-JUL-2004 (NJB) */
/* Updated to support representations of integers in the input */
/* arguments TARGET and OBSRVR. Deleted references in header to */
/* kernel-specific loaders. Made miscellaneous minor corrections */
/* to header comments. */
/* - SPICELIB Version 1.0.2, 12-DEC-2002 (NJB) */
/* Corrected and updated code example in header. */
/* - SPICELIB Version 1.0.1, 1-NOV-1999 (WLT) */
/* Declared routine LTIME to be external. */
/* - SPICELIB Version 1.0.0, 03-SEP-1999 (NJB) (JEM) */
/* -& */
/* $ Index_Entries */
/* DEPRECATED sub-solar point */
/* -& */
/* $ Revisions */
/* - SPICELIB Version 1.1.0, 22-JUL-2004 (NJB) */
/* Updated to support representations of integers in the */
/* input arguments TARGET and OBSRVR: calls to BODN2C */
/* were replaced by calls to BODS2C. */
/* -& */
/* SPICELIB functions */
/* Local parameters */
/* Local variables */
/* Saved variables */
/* Initial values */
/* Standard SPICE error handling. */
if (return_()) {
return 0;
} else {
chkin_("SUBSOL", (ftnlen)6);
}
/* Obtain integer codes for the target and observer. */
bods2c_(target, &trgcde, &found, target_len);
if (! found) {
setmsg_("The target, '#', is not a recognized name for an ephemeris "
"object. The cause of this problem may be that you need an up"
"dated version of the SPICE Toolkit. ", (ftnlen)155);
errch_("#", target, (ftnlen)1, target_len);
sigerr_("SPICE(IDCODENOTFOUND)", (ftnlen)21);
chkout_("SUBSOL", (ftnlen)6);
return 0;
}
bods2c_(obsrvr, &obscde, &found, obsrvr_len);
if (! found) {
setmsg_("The observer, '#', is not a recognized name for an ephemeri"
"s object. The cause of this problem may be that you need an "
"updated version of the SPICE Toolkit. ", (ftnlen)157);
errch_("#", obsrvr, (ftnlen)1, obsrvr_len);
sigerr_("SPICE(IDCODENOTFOUND)", (ftnlen)21);
chkout_("SUBSOL", (ftnlen)6);
return 0;
}
/* Check the input body codes. If they are equal, signal */
/* an error. */
if (obscde == trgcde) {
setmsg_("In computing the sub-observer point, the observing body and"
" target body are the same. Both are #.", (ftnlen)97);
errch_("#", obsrvr, (ftnlen)1, obsrvr_len);
sigerr_("SPICE(BODIESNOTDISTINCT)", (ftnlen)24);
chkout_("SUBSOL", (ftnlen)6);
return 0;
}
/* Get the radii of the target body from the kernel pool. */
bodvcd_(&trgcde, "RADII", &c__3, &nradii, radii, (ftnlen)5);
/* Find the name of the body-fixed frame associated with the */
/* target body. We'll want the state of the target relative to */
/* the observer in this body-fixed frame. */
cidfrm_(&trgcde, &frcode, frname, &found, (ftnlen)80);
if (! found) {
setmsg_("No body-fixed frame is associated with target body #; a fra"
"me kernel must be loaded to make this association. Consult "
"the FRAMES Required Reading for details.", (ftnlen)159);
errch_("#", target, (ftnlen)1, target_len);
sigerr_("SPICE(NOFRAME)", (ftnlen)14);
chkout_("SUBSOL", (ftnlen)6);
return 0;
}
/* If we're using aberration corrections, we'll need the */
/* one way light time from the target to the observer. Otherwise, */
/* we set the time time to zero. */
if (eqstr_(abcorr, "NONE", abcorr_len, (ftnlen)4)) {
lt = 0.;
ettarg = *et;
} else {
ltime_(et, &obscde, "<-", &trgcde, &ettarg, <, (ftnlen)2);
}
/* Determine the position of the sun in target body-fixed */
/* coordinates. */
/* Call SPKEZ to compute the position of the sun as seen from the */
/* target body and the light time between them SUNLT. This state is */
/* evaluated at the target epoch ETTARG. We request that the */
/* coordinates of the target-sun position vector POS be returned */
/* relative to the body fixed reference frame associated with the */
/* target body, using aberration corrections specified by the input */
/* argument ABCORR. */
spkpos_("SUN", &ettarg, frname, abcorr, target, pos, &sunlt, (ftnlen)3, (
ftnlen)80, abcorr_len, target_len);
/* Find the sub-solar point using the specified geometric definition. */
if (eqstr_(method, "Near point", method_len, (ftnlen)10)) {
/* Locate the nearest point to the sun on the target. */
nearpt_(pos, radii, &radii[1], &radii[2], spoint, &alt);
} else if (eqstr_(method, "Intercept", method_len, (ftnlen)9)) {
surfpt_(origin, pos, radii, &radii[1], &radii[2], spoint, &found);
/* Since the line in question passes through the center of the */
/* target, there will always be a surface intercept. So we should */
/* never have FOUND = .FALSE. */
if (! found) {
setmsg_("Call to SURFPT returned FOUND=FALSE even though vertex "
"of ray is at target center. This indicates a bug. Please"
" contact NAIF.", (ftnlen)125);
sigerr_("SPICE(BUG)", (ftnlen)10);
chkout_("SUBSOL", (ftnlen)6);
return 0;
}
} else {
setmsg_("The computation method # was not recognized. Allowed values"
" are \"Near point\" and \"Intercept.\"", (ftnlen)93);
errch_("#", method, (ftnlen)1, method_len);
sigerr_("SPICE(DUBIOUSMETHOD)", (ftnlen)20);
chkout_("SUBSOL", (ftnlen)6);
return 0;
}
chkout_("SUBSOL", (ftnlen)6);
return 0;
} /* subsol_ */
/* $Procedure ET2LST ( ET to Local Solar Time ) */
/* Subroutine */ int et2lst_(doublereal *et, integer *body, doublereal *
long__, char *type__, integer *hr, integer *mn, integer *sc, char *
time, char *ampm, ftnlen type_len, ftnlen time_len, ftnlen ampm_len)
{
/* System generated locals */
address a__1[5], a__2[7];
integer i__1[5], i__2[7];
doublereal d__1;
/* Builtin functions */
integer s_cmp(char *, char *, ftnlen, ftnlen);
/* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen), s_cat(char *,
char **, integer *, integer *, ftnlen);
/* Local variables */
doublereal rate, slat, mins;
char h__[2], m[2];
integer n;
doublereal q;
char s[2];
doublereal angle;
char frame[32];
doublereal range;
extern /* Subroutine */ int chkin_(char *, ftnlen), ucase_(char *, char *,
ftnlen, ftnlen), errch_(char *, char *, ftnlen, ftnlen), dpfmt_(
doublereal *, char *, char *, ftnlen, ftnlen);
logical found;
extern /* Subroutine */ int repmi_(char *, char *, integer *, char *,
ftnlen, ftnlen, ftnlen);
doublereal state[6], slong;
extern /* Subroutine */ int spkez_(integer *, doublereal *, char *, char *
, integer *, doublereal *, doublereal *, ftnlen, ftnlen);
doublereal hours;
extern /* Subroutine */ int ljust_(char *, char *, ftnlen, ftnlen);
extern doublereal twopi_(void);
extern /* Subroutine */ int bodc2n_(integer *, char *, logical *, ftnlen);
extern doublereal pi_(void);
char bodnam[36];
doublereal lt;
integer frcode;
extern /* Subroutine */ int cidfrm_(integer *, integer *, char *, logical
*, ftnlen);
extern doublereal brcktd_(doublereal *, doublereal *, doublereal *);
extern /* Subroutine */ int reclat_(doublereal *, doublereal *,
doublereal *, doublereal *), rmaind_(doublereal *, doublereal *,
doublereal *, doublereal *);
doublereal secnds;
extern /* Subroutine */ int pgrrec_(char *, doublereal *, doublereal *,
doublereal *, doublereal *, doublereal *, doublereal *, ftnlen);
char bpmkwd[32];
integer hrampm;
doublereal tmpang;
extern /* Subroutine */ int gdpool_(char *, integer *, integer *, integer
*, doublereal *, logical *, ftnlen);
char amorpm[4];
doublereal tmpsec;
extern /* Subroutine */ int sigerr_(char *, ftnlen), chkout_(char *,
ftnlen), dtpool_(char *, logical *, integer *, char *, ftnlen,
ftnlen), setmsg_(char *, ftnlen), errint_(char *, integer *,
ftnlen);
doublereal mylong, spoint[3];
extern logical return_(void);
char kwtype[1];
extern /* Subroutine */ int intstr_(integer *, char *, ftnlen);
char mytype[32];
doublereal lat;
/* $ Abstract */
/* Given an ephemeris epoch ET, compute the local solar time for */
/* an object on the surface of a body at a specified longitude. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Required_Reading */
/* TIME */
/* $ Keywords */
/* TIME */
/* $ Declarations */
/* $ Brief_I/O */
/* VARIABLE I/O DESCRIPTION */
/* -------- --- -------------------------------------------------- */
/* ET I Epoch in seconds past J2000 epoch */
/* BODY I ID-code of the body of interest */
/* LONG I Longitude of surface point (RADIANS) */
/* TYPE I Type of longitude 'PLANETOCENTRIC', etc. */
/* HR O Local hour on a "24 hour" clock */
/* MN O Minutes past the hour */
/* SC O Seconds past the minute */
/* TIME O String giving local time on 24 hour clock */
/* AMPM O String giving time on A.M./ P.M. scale */
/* $ Detailed_Input */
/* ET is the epoch expressed in TDB seconds past */
/* the J2000 epoch at which a local time is desired. */
/* BODY is the NAIF ID-code of a body on which local */
/* time is to be measured. */
/* LONG is the longitude (either planetocentric or */
/* planetographic) in radians of the site on the */
/* surface of body for which local time should be */
/* computed. */
/* TYPE is the form of longitude supplied by the variable */
/* LONG. Allowed values are 'PLANETOCENTRIC' and */
/* 'PLANETOGRAPHIC'. Note the case of the letters */
/* in TYPE is insignificant. Both 'PLANETOCENTRIC' */
/* and 'planetocentric' are recognized. */
/* $ Detailed_Output */
/* HR is the local "hour" of the site specified at the */
/* epoch ET. Note that an "hour" of local time does not */
/* have the same duration as an hour measured by */
/* conventional clocks. It is simply a representation */
/* of an angle. See the "Particulars" section for a more */
/* complete discussion of the meaning of local time. */
/* MN is the number of "minutes" past the hour of the */
/* local time of the site at the epoch ET. Again note */
/* that a "local minute" is not the same as a minute */
/* you would measure with conventional clocks. */
/* SC is the number of "seconds" past the minute of the */
/* local time of the site at the epoch ET. Again note */
/* that a "local second" is not the same as a second */
/* you would measure with conventional clocks. */
/* TIME is a string expressing the local time */
/* on a "24 hour" local clock. */
/* AMPM is a string expressing the local time on a "12 hour" */
/* local clock together with the traditional AM/PM */
/* label to indicate whether the sun has crossed */
/* the local zenith meridian. */
/* $ Parameters */
/* None. */
/* $ Exceptions */
/* 1) This routine defines local solar time for any point on the */
/* surface of the Sun to be 12:00:00 noon. */
/* 2) If the TYPE of the coordinates is not recognized, the */
/* error 'SPICE(UNKNOWNSYSTEM)' will be signaled. */
/* 3) If the body-fixed frame to associate with BODY cannot be */
/* determined, the error 'SPICE(CANTFINDFRAME)' is signaled. */
/* 4) If insufficient data is available to compute the */
/* location of the sun in body-fixed coordinates, the */
/* error will be diagnosed by a routine called by this one. */
/* 5) If the BODY#_PM keyword required to determine the body */
/* rotation sense is not found in the POOL or if it is found but */
/* is not a numeric keyword with at least two elements, the error */
/* 'SPICE(CANTGETROTATIONTYPE)' is signaled. */
/* $ Files */
/* Suitable SPK and PCK files must be loaded prior to calling this */
/* routine so that the body-fixed position of the sun relative to */
/* BODY can be computed. The PCK files must contain the standard */
/* BODY#_PM keyword need by this routine to determine the body */
/* rotation sense. */
/* When the input longitude is planetographic, the default */
/* interpretation of this value can be overridden using the optional */
/* kernel variable */
/* BODY<body ID>_PGR_POSITIVE_LON */
/* which is normally defined via loading a text kernel. */
/* $ Particulars */
/* This routine returns the local solar time at a user */
/* specified location on a user specified body. */
/* Let SUNLNG be the planetocentric longitude (in degrees) of */
/* the sun as viewed from the center of the body of interest. */
/* Let SITLNG be the planetocentric longitude (in degrees) of */
/* the site for which local time is desired. */
/* We define local time to be 12 + (SITLNG - SUNLNG)/15 */
/* (where appropriate care is taken to map ( SITLNG - SUNLNG ) */
/* into the range from -180 to 180). */
/* Using this definition, we see that from the point of view */
/* of this routine, local solar time is simply a measure of angles */
/* between meridians on the surface of a body. Consequently, */
/* this routine is not appropriate for computing "local times" */
/* in the sense of Pacific Standard Time. For computing times */
/* relative to standard time zones on earth, see the routines */
/* TIMOUT and STR2ET. */
/* Regarding planetographic longitude */
/* ---------------------------------- */
/* In the planetographic coordinate system, longitude is defined */
/* using the spin sense of the body. Longitude is positive to the */
/* west if the spin is prograde and positive to the east if the spin */
/* is retrograde. The spin sense is given by the sign of the first */
/* degree term of the time-dependent polynomial for the body's prime */
/* meridian Euler angle "W": the spin is retrograde if this term is */
/* negative and prograde otherwise. For the sun, planets, most */
/* natural satellites, and selected asteroids, the polynomial */
/* expression for W may be found in a SPICE PCK kernel. */
/* The earth, moon, and sun are exceptions: planetographic longitude */
/* is measured positive east for these bodies. */
/* If you wish to override the default sense of positive */
/* planetographic longitude for a particular body, you can do so by */
/* defining the kernel variable */
/* BODY<body ID>_PGR_POSITIVE_LON */
/* where <body ID> represents the NAIF ID code of the body. This */
/* variable may be assigned either of the values */
/* 'WEST' */
/* 'EAST' */
/* For example, you can have this routine treat the longitude */
/* of the earth as increasing to the west using the kernel */
/* variable assignment */
/* BODY399_PGR_POSITIVE_LON = 'WEST' */
/* Normally such assignments are made by placing them in a text */
/* kernel and loading that kernel via FURNSH. */
/* $ Examples */
/* The following code fragment illustrates how you */
/* could print the local time at a site on Mars with */
/* planetographic longitude 326.17 deg E at epoch ET. */
/* (This example assumes all required SPK and PCK files have */
/* been loaded). */
/* Convert the longitude to radians, set the type of the longitude */
/* and make up a mnemonic for Mars' ID-code. */
/* LONG = 326.17 * RPD() */
/* TYPE = 'PLANETOGRAPHIC' */
/* MARS = 499 */
/* CALL ET2LST ( ET, MARS, LONG, TYPE, HR, MN, SC, TIME, AMPM ) */
/* WRITE (*,*) 'The local time at Mars 326.17 degrees E ' */
/* WRITE (*,*) 'planetographic longitude is: ', AMPM */
/* $ Restrictions */
/* This routine relies on being able to determine the name */
/* of the body-fixed frame associated with BODY through the */
/* frames subsystem. If the BODY specified is NOT one of the */
/* nine planets or their satellites, you will need to load */
/* an appropriate frame definition kernel that contains */
/* the relationship between the body id and the body-fixed frame */
/* name. See the FRAMES required reading for more details */
/* on specifying this relationship. */
/* The routine determines the body rotation sense using the PCK */
/* keyword BODY#_PM. Therefore, you will need to a text PCK file */
/* defining the complete set of the standard PCK body rotation */
/* keywords for the body of interest. The text PCK file must be */
/* loaded independently of whether a binary PCK file providing */
/* rotation data for the same body is loaded or not. */
/* Although it is not currently the case for any of the Solar System */
/* bodies, it is possible that the retrograde rotation rate of a */
/* body would be slower than the orbital rate of the body rotation */
/* around the Sun. The routine does not account for such cases; for */
/* them it will compute incorrect the local time progressing */
/* backwards. */
/* $ Literature_References */
/* None. */
/* $ Author_and_Institution */
/* W.L. Taber (JPL) */
/* $ Version */
/* - SPICELIB Version 3.0.2, 18-APR-2014 (BVS) */
/* Minor edits to long error messages. */
/* - SPICELIB Version 3.0.1, 09-SEP-2009 (EDW) */
/* Header edits: deleted a spurious C$ marker from the */
/* "Detailed_Output" section. The existence of the marker */
/* caused a failure in the HTML documentation creation script. */
/* Deleted the "Revisions" section as it contained several */
/* identical entries from the "Version" section. */
/* Corrected order of header sections. */
/* - SPICELIB Version 3.0.0, 28-OCT-2006 (BVS) */
/* Bug fix: incorrect computation of the local time for the */
/* bodies with the retrograde rotation causing the local time to */
/* flow backwards has been fixed. The local time for all types of */
/* bodies now progresses as expected -- midnight, increasing AM */
/* hours, noon, increasing PM hours, next midnight, and so on. */
/* - SPICELIB Version 2.0.0, 03-NOV-2005 (NJB) */
/* Bug fix: treatment of planetographic longitude has been */
/* updated to be consistent with the SPICE planetographic/ */
/* rectangular coordinate conversion routines. The effect of */
/* this change is that the default sense of positive longitude */
/* for the moon is now east; also, the default sense of positive */
/* planetographic longitude now may be overridden for any body */
/* (see Particulars above). */
/* Updated to remove non-standard use of duplicate arguments */
/* in RMAIND calls. */
/* - SPICELIB Version 1.1.0, 24-MAR-1998 (WLT) */
/* The integer variable SUN was never initialized in the */
/* previous version of the routine. Now it is set to */
/* the proper value of 10. */
/* - SPICELIB Version 1.0.0, 9-JUL-1997 (WLT) */
/* -& */
/* $ Index_Entries */
/* Compute the local time for a point on a body. */
/* -& */
/* SPICELIB Functions */
/* Local parameters */
/* Local Variables */
/* Standard SPICE error handling. */
if (return_()) {
return 0;
}
chkin_("ET2LST", (ftnlen)6);
ljust_(type__, mytype, type_len, (ftnlen)32);
ucase_(mytype, mytype, (ftnlen)32, (ftnlen)32);
if (s_cmp(mytype, "PLANETOGRAPHIC", (ftnlen)32, (ftnlen)14) == 0) {
/* Find planetocentric longitude corresponding to the input */
/* longitude. We first represent in rectangular coordinates */
/* a surface point having zero latitude, zero altitude, and */
/* the input planetographic longitude. We then find the */
/* planetocentric longitude of this point. */
/* Since PGRREC accepts a body name, map the input code to */
/* a name, if possible. Otherwise, just convert the input code */
/* to a string. */
bodc2n_(body, bodnam, &found, (ftnlen)36);
if (! found) {
intstr_(body, bodnam, (ftnlen)36);
}
/* Convert planetographic coordinates to rectangular coordinates. */
/* All we care about here is longitude. Set the other inputs */
/* as follows: */
/* Latitude = 0 */
/* Altitude = 0 */
/* Equatorial radius = 1 */
/* Flattening factor = 0 */
pgrrec_(bodnam, long__, &c_b4, &c_b4, &c_b6, &c_b4, spoint, (ftnlen)
36);
/* The output MYLONG is planetocentric longitude. The other */
/* outputs are not used. Note that the variable RANGE appears */
/* later in another RECLAT call; it's not used after that. */
reclat_(spoint, &range, &mylong, &lat);
} else if (s_cmp(mytype, "PLANETOCENTRIC", (ftnlen)32, (ftnlen)14) == 0) {
mylong = *long__;
} else {
setmsg_("The coordinate system '#' is not a recognized system of lon"
"gitude. The recognized systems are 'PLANETOCENTRIC' and 'PL"
"ANETOGRAPHIC'. ", (ftnlen)134);
errch_("#", type__, (ftnlen)1, type_len);
sigerr_("SPICE(UNKNOWNSYSTEM)", (ftnlen)20);
chkout_("ET2LST", (ftnlen)6);
return 0;
}
/* It's always noon on the surface of the sun. */
if (*body == 10) {
*hr = 12;
*mn = 0;
*sc = 0;
s_copy(time, "12:00:00", time_len, (ftnlen)8);
s_copy(ampm, "12:00:00 P.M.", ampm_len, (ftnlen)13);
chkout_("ET2LST", (ftnlen)6);
return 0;
}
/* Get the body-fixed position of the sun. */
cidfrm_(body, &frcode, frame, &found, (ftnlen)32);
if (! found) {
setmsg_("The body-fixed frame associated with body # could not be de"
"termined. This information needs to be \"loaded\" via a fra"
"mes definition kernel. See frames.req for more details. ", (
ftnlen)174);
errint_("#", body, (ftnlen)1);
sigerr_("SPICE(CANTFINDFRAME)", (ftnlen)20);
chkout_("ET2LST", (ftnlen)6);
return 0;
}
spkez_(&c__10, et, frame, "LT+S", body, state, <, (ftnlen)32, (ftnlen)4)
;
reclat_(state, &range, &slong, &slat);
angle = mylong - slong;
/* Force the angle into the region from -PI to PI */
d__1 = twopi_();
rmaind_(&angle, &d__1, &q, &tmpang);
angle = tmpang;
if (angle > pi_()) {
angle -= twopi_();
}
/* Get the rotation sense of the body and invert the angle if the */
/* rotation sense is retrograde. Use the BODY#_PM PCK keyword to */
/* determine the sense of the body rotation. */
s_copy(bpmkwd, "BODY#_PM", (ftnlen)32, (ftnlen)8);
repmi_(bpmkwd, "#", body, bpmkwd, (ftnlen)32, (ftnlen)1, (ftnlen)32);
dtpool_(bpmkwd, &found, &n, kwtype, (ftnlen)32, (ftnlen)1);
if (! found || *(unsigned char *)kwtype != 'N' || n < 2) {
setmsg_("The rotation type for the body # could not be determined be"
"cause the # keyword was either not found in the POOL or or i"
"t was not of the expected type and/or dimension. This keywor"
"d is usually provided via a planetary constants kernel. See "
"pck.req for more details. ", (ftnlen)265);
errint_("#", body, (ftnlen)1);
errch_("#", bpmkwd, (ftnlen)1, (ftnlen)32);
sigerr_("SPICE(CANTGETROTATIONTYPE)", (ftnlen)26);
chkout_("ET2LST", (ftnlen)6);
return 0;
} else {
/* If the rotation rate is negative, invert the angle. */
gdpool_(bpmkwd, &c__2, &c__1, &n, &rate, &found, (ftnlen)32);
if (rate < 0.) {
angle = -angle;
}
}
/* Convert the angle to "angle seconds" before or after local noon. */
secnds = angle * 86400. / twopi_();
secnds = brcktd_(&secnds, &c_b32, &c_b33);
/* Get the hour, and minutes components of the local time. */
rmaind_(&secnds, &c_b34, &hours, &tmpsec);
rmaind_(&tmpsec, &c_b35, &mins, &secnds);
/* Construct the integer components of the local time. */
*hr = (integer) hours + 12;
*mn = (integer) mins;
*sc = (integer) secnds;
/* Set the A.M./P.M. components of local time. */
if (*hr == 24) {
*hr = 0;
hrampm = 12;
s_copy(amorpm, "A.M.", (ftnlen)4, (ftnlen)4);
} else if (*hr > 12) {
hrampm = *hr - 12;
s_copy(amorpm, "P.M.", (ftnlen)4, (ftnlen)4);
} else if (*hr == 12) {
hrampm = 12;
s_copy(amorpm, "P.M.", (ftnlen)4, (ftnlen)4);
} else if (*hr == 0) {
hrampm = 12;
s_copy(amorpm, "A.M.", (ftnlen)4, (ftnlen)4);
} else {
hrampm = *hr;
s_copy(amorpm, "A.M.", (ftnlen)4, (ftnlen)4);
}
/* Now construct the two strings we need. */
hours = (doublereal) (*hr);
mins = (doublereal) (*mn);
secnds = (doublereal) (*sc);
dpfmt_(&hours, "0x", h__, (ftnlen)2, (ftnlen)2);
dpfmt_(&mins, "0x", m, (ftnlen)2, (ftnlen)2);
dpfmt_(&secnds, "0x", s, (ftnlen)2, (ftnlen)2);
/* Writing concatenation */
i__1[0] = 2, a__1[0] = h__;
i__1[1] = 1, a__1[1] = ":";
i__1[2] = 2, a__1[2] = m;
i__1[3] = 1, a__1[3] = ":";
i__1[4] = 2, a__1[4] = s;
s_cat(time, a__1, i__1, &c__5, time_len);
hours = (doublereal) hrampm;
dpfmt_(&hours, "0x", h__, (ftnlen)2, (ftnlen)2);
/* Writing concatenation */
i__2[0] = 2, a__2[0] = h__;
i__2[1] = 1, a__2[1] = ":";
i__2[2] = 2, a__2[2] = m;
i__2[3] = 1, a__2[3] = ":";
i__2[4] = 2, a__2[4] = s;
i__2[5] = 1, a__2[5] = " ";
i__2[6] = 4, a__2[6] = amorpm;
s_cat(ampm, a__2, i__2, &c__7, ampm_len);
chkout_("ET2LST", (ftnlen)6);
return 0;
} /* et2lst_ */
/* $Procedure SUBPT ( Sub-observer point ) */
/* Subroutine */ int subpt_(char *method, char *target, doublereal *et, char *
abcorr, char *obsrvr, doublereal *spoint, doublereal *alt, ftnlen
method_len, ftnlen target_len, ftnlen abcorr_len, ftnlen obsrvr_len)
{
/* Initialized data */
static doublereal origin[3] = { 0.,0.,0. };
doublereal radii[3];
extern /* Subroutine */ int chkin_(char *, ftnlen), errch_(char *, char *,
ftnlen, ftnlen);
logical found;
extern doublereal vdist_(doublereal *, doublereal *);
extern /* Subroutine */ int spkez_(integer *, doublereal *, char *, char *
, integer *, doublereal *, doublereal *, ftnlen, ftnlen);
extern logical eqstr_(char *, char *, ftnlen, ftnlen);
extern /* Subroutine */ int bods2c_(char *, integer *, logical *, ftnlen);
integer obscde;
doublereal lt;
extern /* Subroutine */ int bodvcd_(integer *, char *, integer *, integer
*, doublereal *, ftnlen);
integer frcode;
extern /* Subroutine */ int cidfrm_(integer *, integer *, char *, logical
*, ftnlen);
integer nradii;
char frname[80];
integer trgcde;
extern /* Subroutine */ int nearpt_(doublereal *, doublereal *,
doublereal *, doublereal *, doublereal *, doublereal *), sigerr_(
char *, ftnlen), chkout_(char *, ftnlen), setmsg_(char *, ftnlen);
doublereal tstate[6];
extern logical return_(void);
extern /* Subroutine */ int vminus_(doublereal *, doublereal *), surfpt_(
doublereal *, doublereal *, doublereal *, doublereal *,
doublereal *, doublereal *, logical *);
doublereal pos[3];
/* $ Abstract */
/* Deprecated: This routine has been superseded by the SPICELIB */
/* routine SUBPNT. This routine is supported for purposes of */
/* backward compatibility only. */
/* Compute the rectangular coordinates of the sub-observer point on */
/* a target body at a particular epoch, optionally corrected for */
/* planetary (light time) and stellar aberration. Return these */
/* coordinates expressed in the body-fixed frame associated with the */
/* target body. Also, return the observer's altitude above the */
/* target body. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Required_Reading */
/* FRAMES */
/* PCK */
/* SPK */
/* TIME */
/* $ Keywords */
/* GEOMETRY */
/* $ Declarations */
/* $ Brief_I/O */
/* Variable I/O Description */
/* -------- --- -------------------------------------------------- */
/* METHOD I Computation method. */
/* TARGET I Name of target body. */
/* ET I Epoch in ephemeris seconds past J2000 TDB. */
/* ABCORR I Aberration correction. */
/* OBSRVR I Name of observing body. */
/* SPOINT O Sub-observer point on the target body. */
/* ALT O Altitude of the observer above the target body. */
/* $ Detailed_Input */
/* METHOD is a short string specifying the computation method */
/* to be used. The choices are: */
/* 'Near point' The sub-observer point is */
/* defined as the nearest point on */
/* the target relative to the */
/* observer. */
/* 'Intercept' The sub-observer point is */
/* defined as the target surface */
/* intercept of the line */
/* containing the observer and the */
/* target's center. */
/* In both cases, the intercept computation treats the */
/* surface of the target body as a triaxial ellipsoid. */
/* The ellipsoid's radii must be available in the kernel */
/* pool. */
/* Neither case nor white space are significant in */
/* METHOD. For example, the string ' NEARPOINT' is */
/* valid. */
/* TARGET is the name of a target body. Optionally, you may */
/* supply the integer ID code for the object as */
/* an integer string. For example both 'MOON' and */
/* '301' are legitimate strings that indicate the */
/* moon is the target body. This routine assumes */
/* that this body is modeled by a tri-axial ellipsoid, */
/* and that a PCK file containing its radii has been */
/* loaded into the kernel pool via FURNSH. */
/* ET is the epoch in ephemeris seconds past J2000 at which */
/* the sub-observer point on the target body is to be */
/* computed. */
/* ABCORR indicates the aberration corrections to be applied */
/* when computing the observer-target state. ABCORR */
/* may be any of the following. */
/* 'NONE' Apply no correction. Return the */
/* geometric sub-observer point on the */
/* target body. */
/* 'LT' Correct for planetary (light time) */
/* aberration. Both the state and rotation */
/* of the target body are corrected for */
/* light time. */
/* 'LT+S' Correct for planetary (light time) and */
/* stellar aberrations. Both the state and */
/* rotation of the target body are */
/* corrected for light time. */
/* 'CN' Converged Newtonian light time */
/* corrections. This is the same as LT */
/* corrections but with further iterations */
/* to a converged Newtonian light time */
/* solution. Given that relativistic */
/* effects may be as large as the higher */
/* accuracy achieved by this computation, */
/* this is correction is seldom worth the */
/* additional computations required unless */
/* the user incorporates additional */
/* relativistic corrections. Both the */
/* state and rotation of the target body */
/* are corrected for light time. */
/* 'CN+S' Converged Newtonian light time */
/* corrections and stellar aberration. */
/* Both the state and rotation of the */
/* target body are corrected for light */
/* time. */
/* OBSRVR is the name of the observing body. This is typically */
/* a spacecraft, the earth, or a surface point on the */
/* earth. Optionally, you may supply the ID code of */
/* the object as an integer string. For example, both */
/* 'EARTH' and '399' are legitimate strings to supply */
/* to indicate the observer is Earth. */
/* $ Detailed_Output */
/* SPOINT is the sub-observer point on the target body at ET */
/* expressed relative to the body-fixed frame of the */
/* target body. */
/* The sub-observer point is defined either as the point */
/* on the target body that is closest to the observer, */
/* or the target surface intercept of the line from the */
/* observer to the target's center; the input argument */
/* METHOD selects the definition to be used. */
/* The body-fixed frame, which is time-dependent, is */
/* evaluated at ET if ABCORR is 'NONE'; otherwise the */
/* frame is evaluated at ET-LT, where LT is the one-way */
/* light time from target to observer. */
/* The state of the target body is corrected for */
/* aberration as specified by ABCORR; the corrected */
/* state is used in the geometric computation. As */
/* indicated above, the rotation of the target is */
/* retarded by one-way light time if ABCORR specifies */
/* that light time correction is to be done. */
/* ALT is the "altitude" of the observer above the target */
/* body. When METHOD specifies a "near point" */
/* computation, ALT is truly altitude in the standard */
/* geometric sense: the length of a segment dropped from */
/* the observer to the target's surface, such that the */
/* segment is perpendicular to the surface at the */
/* contact point SPOINT. */
/* When METHOD specifies an "intercept" computation, ALT */
/* is still the length of the segment from the observer */
/* to the surface point SPOINT, but this segment in */
/* general is not perpendicular to the surface. */
/* $ Parameters */
/* None. */
/* $ Exceptions */
/* If any of the listed errors occur, the output arguments are */
/* left unchanged. */
/* 1) If the input argument METHOD is not recognized, the error */
/* SPICE(DUBIOUSMETHOD) is signaled. */
/* 2) If either of the input body names TARGET or OBSRVR cannot be */
/* mapped to NAIF integer codes, the error SPICE(IDCODENOTFOUND) */
/* is signaled. */
/* 3) If OBSRVR and TARGET map to the same NAIF integer ID codes, the */
/* error SPICE(BODIESNOTDISTINCT) is signaled. */
/* 4) If frame definition data enabling the evaluation of the state */
/* of the target relative to the observer in target body-fixed */
/* coordinates have not been loaded prior to calling SUBPT, the */
/* error will be diagnosed and signaled by a routine in the call */
/* tree of this routine. */
/* 5) If the specified aberration correction is not recognized, the */
/* error will be diagnosed and signaled by a routine in the call */
/* tree of this routine. */
/* 6) If insufficient ephemeris data have been loaded prior to */
/* calling SUBPT, the error will be diagnosed and signaled by a */
/* routine in the call tree of this routine. */
/* 7) If the triaxial radii of the target body have not been loaded */
/* into the kernel pool prior to calling SUBPT, the error will be */
/* diagnosed and signaled by a routine in the call tree of this */
/* routine. */
/* 8) The target must be an extended body: if any of the radii of */
/* the target body are non-positive, the error will be diagnosed */
/* and signaled by routines in the call tree of this routine. */
/* 9) If PCK data supplying a rotation model for the target body */
/* have not been loaded prior to calling SUBPT, the error will be */
/* diagnosed and signaled by a routine in the call tree of this */
/* routine. */
/* $ Files */
/* Appropriate SPK, PCK, and frame kernels must be loaded */
/* prior by the calling program before this routine is called. */
/* The following data are required: */
/* - SPK data: ephemeris data for target and observer must be */
/* loaded. If aberration corrections are used, the states of */
/* target and observer relative to the solar system barycenter */
/* must be calculable from the available ephemeris data. */
/* Typically ephemeris data are made available by loading one */
/* or more SPK files via FURNSH. */
/* - PCK data: triaxial radii for the target body must be loaded */
/* into the kernel pool. Typically this is done by loading a */
/* text PCK file via FURNSH. */
/* - Further PCK data: rotation data for the target body must */
/* be loaded. These may be provided in a text or binary PCK */
/* file. Either type of file may be loaded via FURNSH. */
/* - Frame data: if a frame definition is required to convert */
/* the observer and target states to the body-fixed frame of */
/* the target, that definition must be available in the kernel */
/* pool. Typically the definition is supplied by loading a */
/* frame kernel via FURNSH. */
/* In all cases, kernel data are normally loaded once per program */
/* run, NOT every time this routine is called. */
/* $ Particulars */
/* SUBPT computes the sub-observer point on a target body. */
/* (The sub-observer point is commonly called the sub-spacecraft */
/* point when the observer is a spacecraft.) SUBPT also */
/* determines the altitude of the observer above the target body. */
/* There are two different popular ways to define the sub-observer */
/* point: "nearest point on target to observer" or "target surface */
/* intercept of line containing observer and target." These */
/* coincide when the target is spherical and generally are distinct */
/* otherwise. */
/* When comparing sub-point computations with results from sources */
/* other than SPICE, it's essential to make sure the same geometric */
/* definitions are used. */
/* $ Examples */
/* The numerical results shown for this example may differ across */
/* platforms. The results depend on the SPICE kernels used as */
/* input, the compiler and supporting libraries, and the machine */
/* specific arithmetic implementation. */
/* In the following example program, the file */
/* spk_m_031103-040201_030502.bsp */
/* is a binary SPK file containing data for Mars Global Surveyor, */
/* Mars, and the Sun for a time interval bracketing the date */
/* 2004 JAN 1 12:00:00 UTC. */
/* pck00007.tpc is a planetary constants kernel file containing */
/* radii and rotation model constants. naif0007.tls is a */
/* leapseconds kernel. */
/* Find the sub-observer point of the Mars Global Surveyor (MGS) */
/* spacecraft on Mars for a specified time. Perform the computation */
/* twice, using both the "intercept" and "near point" options. */
/* IMPLICIT NONE */
/* CHARACTER*25 METHOD ( 2 ) */
/* INTEGER I */
/* DOUBLE PRECISION ALT */
/* DOUBLE PRECISION DPR */
/* DOUBLE PRECISION ET */
/* DOUBLE PRECISION LAT */
/* DOUBLE PRECISION LON */
/* DOUBLE PRECISION RADIUS */
/* DOUBLE PRECISION SPOINT ( 3 ) */
/* DATA METHOD / 'Intercept', 'Near point' / */
/* C */
/* C Load kernel files. */
/* C */
/* CALL FURNSH ( 'naif0007.tls' ) */
/* CALL FURNSH ( 'pck00007.tpc' ) */
/* CALL FURNSH ( 'spk_m_031103-040201_030502.bsp' ) */
/* C */
/* C Convert the UTC request time to ET (seconds past */
/* C J2000, TDB). */
/* C */
/* CALL STR2ET ( '2004 JAN 1 12:00:00', ET ) */
/* C */
/* C Compute sub-spacecraft point using light time and stellar */
/* C aberration corrections. Use the "target surface intercept" */
/* C definition of sub-spacecraft point on the first loop */
/* C iteration, and use the "near point" definition on the */
/* C second. */
/* C */
/* DO I = 1, 2 */
/* CALL SUBPT ( METHOD(I), */
/* . 'MARS', ET, 'LT+S', */
/* . 'MGS', SPOINT, ALT ) */
/* C */
/* C Convert rectangular coordinates to planetocentric */
/* C latitude and longitude. Convert radians to degrees. */
/* C */
/* CALL RECLAT ( SPOINT, RADIUS, LON, LAT ) */
/* LON = LON * DPR () */
/* LAT = LAT * DPR () */
/* C */
/* C Write the results. */
/* C */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) 'Computation method: ', METHOD(I) */
/* WRITE (*,*) ' ' */
/* WRITE (*,*) ' Radius (km) = ', RADIUS */
/* WRITE (*,*) ' Planetocentric Latitude (deg) = ', LAT */
/* WRITE (*,*) ' Planetocentric Longitude (deg) = ', LON */
/* WRITE (*,*) ' Altitude (km) = ', ALT */
/* WRITE (*,*) ' ' */
/* END DO */
/* END */
/* When this program is executed, the output will be: */
/* Computation method: Intercept */
/* Radius (km) = 3387.97077 */
/* Planetocentric Latitude (deg) = -39.7022724 */
/* Planetocentric Longitude (deg) = -159.226663 */
/* Altitude (km) = 373.173506 */
/* Computation method: Near point */
/* Radius (km) = 3387.9845 */
/* Planetocentric Latitude (deg) = -39.6659329 */
/* Planetocentric Longitude (deg) = -159.226663 */
/* Altitude (km) = 373.166636 */
/* $ Restrictions */
/* None. */
/* $ Literature_References */
/* None. */
/* $ Author_and_Institution */
/* C.H. Acton (JPL) */
/* N.J. Bachman (JPL) */
/* J.E. McLean (JPL) */
/* $ Version */
/* - SPICELIB Version 1.2.3, 18-MAY-2010 (BVS) */
/* Index line now states that this routine is deprecated. */
/* - SPICELIB Version 1.2.2, 17-MAR-2009 (EDW) */
/* Typo correction in Required_Reading, changed */
/* FRAME to FRAMES. */
/* - SPICELIB Version 1.2.1, 07-FEB-2008 (NJB) */
/* Abstract now states that this routine is deprecated. */
/* - SPICELIB Version 1.2.0, 24-OCT-2005 (NJB) */
/* Replaced call to BODVAR with call to BODVCD. */
/* - SPICELIB Version 1.1.0, 21-JUL-2004 (EDW) */
/* Changed BODN2C call to BODS2C giving the routine */
/* the capability to accept string representations of */
/* interger IDs for TARGET and OBSRVR. */
/* - SPICELIB Version 1.0.1, 27-JUL-2003 (NJB) (CHA) */
/* Various header corrections were made. The example program */
/* was upgraded to use real kernels, and the program's output is */
/* shown. */
/* - SPICELIB Version 1.0.0, 03-SEP-1999 (NJB) (JEM) */
/* -& */
/* $ Index_Entries */
/* DEPRECATED sub-observer point */
/* -& */
/* SPICELIB functions */
/* Local parameters */
/* Local variables */
/* Saved variables */
/* Initial values */
/* Standard SPICE error handling. */
if (return_()) {
return 0;
} else {
chkin_("SUBPT", (ftnlen)5);
}
/* Obtain integer codes for the target and observer. */
/* Target... */
bods2c_(target, &trgcde, &found, target_len);
if (! found) {
setmsg_("The target, '#', is not a recognized name for an ephemeris "
"object. The cause of this problem may be that you need an up"
"dated version of the SPICE Toolkit. ", (ftnlen)155);
errch_("#", target, (ftnlen)1, target_len);
sigerr_("SPICE(IDCODENOTFOUND)", (ftnlen)21);
chkout_("SUBPT", (ftnlen)5);
return 0;
}
/* ...observer. */
bods2c_(obsrvr, &obscde, &found, obsrvr_len);
if (! found) {
setmsg_("The observer, '#', is not a recognized name for an ephemeri"
"s object. The cause of this problem may be that you need an "
"updated version of the SPICE Toolkit. ", (ftnlen)157);
errch_("#", obsrvr, (ftnlen)1, obsrvr_len);
sigerr_("SPICE(IDCODENOTFOUND)", (ftnlen)21);
chkout_("SUBPT", (ftnlen)5);
return 0;
}
/* Check the input body codes. If they are equal, signal */
/* an error. */
if (obscde == trgcde) {
setmsg_("In computing the sub-observer point, the observing body and"
" target body are the same. Both are #.", (ftnlen)97);
errch_("#", obsrvr, (ftnlen)1, obsrvr_len);
sigerr_("SPICE(BODIESNOTDISTINCT)", (ftnlen)24);
chkout_("SUBPT", (ftnlen)5);
return 0;
}
/* Get the radii of the target body from the kernel pool. */
bodvcd_(&trgcde, "RADII", &c__3, &nradii, radii, (ftnlen)5);
/* Find the name of the body-fixed frame associated with the */
/* target body. We'll want the state of the target relative to */
/* the observer in this body-fixed frame. */
cidfrm_(&trgcde, &frcode, frname, &found, (ftnlen)80);
if (! found) {
setmsg_("No body-fixed frame is associated with target body #; a fra"
"me kernel must be loaded to make this association. Consult "
"the FRAMES Required Reading for details.", (ftnlen)159);
errch_("#", target, (ftnlen)1, target_len);
sigerr_("SPICE(NOFRAME)", (ftnlen)14);
chkout_("SUBPT", (ftnlen)5);
return 0;
}
/* Determine the position of the observer in target */
/* body-fixed coordinates. */
/* - Call SPKEZR to compute the position of the target */
/* body as seen from the observing body and the light time */
/* (LT) between them. SPKEZR returns a state which is */
/* the position and velocity, but we'll only use the position */
/* which is the first three elements. We request that the */
/* coordinates of POS be returned relative to the body fixed */
/* reference frame associated with the target body, using */
/* aberration corrections specified by the input argument */
/* ABCORR. */
/* - Call VMINUS to negate the direction of the vector (POS) */
/* so it will be the position of the observer as seen from */
/* the target body in target body fixed coordinates. */
/* Note that this result is not the same as the result of */
/* calling SPKEZR with the target and observer switched. We */
/* computed the vector FROM the observer TO the target in */
/* order to get the proper light time and stellar aberration */
/* corrections (if requested). Now we need the inverse of */
/* that corrected vector in order to compute the sub-point. */
spkez_(&trgcde, et, frname, abcorr, &obscde, tstate, <, (ftnlen)80,
abcorr_len);
/* Negate the target's state to obtain the position of the observer */
/* relative to the target. */
vminus_(tstate, pos);
/* Find the sub-point and "altitude" (distance from observer to */
/* sub-point) using the specified geometric definition. */
if (eqstr_(method, "Near point", method_len, (ftnlen)10)) {
/* Locate the nearest point to the observer on the target. */
nearpt_(pos, radii, &radii[1], &radii[2], spoint, alt);
} else if (eqstr_(method, "Intercept", method_len, (ftnlen)9)) {
surfpt_(origin, pos, radii, &radii[1], &radii[2], spoint, &found);
/* Since the line in question passes through the center of the */
/* target, there will always be a surface intercept. So we should */
/* never have FOUND = .FALSE. */
if (! found) {
setmsg_("Call to SURFPT returned FOUND=FALSE even though vertex "
"of ray is at target center. This indicates a bug. Please"
" contact NAIF.", (ftnlen)125);
sigerr_("SPICE(BUG)", (ftnlen)10);
chkout_("SUBPT", (ftnlen)5);
return 0;
}
/* SURFPT doesn't compute altitude, so do it here. */
*alt = vdist_(pos, spoint);
} else {
setmsg_("The computation method # was not recognized. Allowed values"
" are \"Near point\" and \"Intercept.\"", (ftnlen)93);
errch_("#", method, (ftnlen)1, method_len);
sigerr_("SPICE(DUBIOUSMETHOD)", (ftnlen)20);
chkout_("SUBPT", (ftnlen)5);
return 0;
}
chkout_("SUBPT", (ftnlen)5);
return 0;
} /* subpt_ */
