예제 #1
0
/* $Procedure   STCF01 (STAR catalog type 1, find stars in RA-DEC box) */
/* Subroutine */ int stcf01_(char *catnam, doublereal *westra, doublereal *
	eastra, doublereal *sthdec, doublereal *nthdec, integer *nstars, 
	ftnlen catnam_len)
{
    /* Builtin functions */
    /* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen);

    /* Local variables */
    extern /* Subroutine */ int chkin_(char *, ftnlen), errch_(char *, char *,
	     ftnlen, ftnlen);
    doublereal ramin;
    extern /* Subroutine */ int repmc_(char *, char *, char *, char *, ftnlen,
	     ftnlen, ftnlen, ftnlen);
    doublereal ramax;
    extern /* Subroutine */ int repmd_(char *, char *, doublereal *, integer *
	    , char *, ftnlen, ftnlen, ftnlen);
    logical error;
    char query[512], qrytm1[512], qrytm2[512];
    doublereal decmin;
    extern /* Subroutine */ int ekfind_(char *, integer *, logical *, char *, 
	    ftnlen, ftnlen);
    doublereal decmax;
    extern /* Subroutine */ int sigerr_(char *, ftnlen), chkout_(char *, 
	    ftnlen);
    char errmsg[512];
    extern /* Subroutine */ int setmsg_(char *, ftnlen);
    extern logical return_(void);
    extern doublereal dpr_(void);

/* $ Abstract */

/*     Search through a type 1 star catalog and return the number of */
/*     stars within a specified RA - DEC rectangle. */

/* $ 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 */

/*     EK */

/* $ Keywords */

/*     None. */

/* $ Declarations */
/* $ Brief_I/O */

/*     Variable  I/O  Description */
/*     --------  ---  -------------------------------------------------- */
/*     CATNAM      I   Catalog table name. */
/*     WESTRA      I   Western most right ascension in radians. */
/*     EASTRA      I   Eastern most right ascension in radians. */
/*     STHDEC      I   Southern most declination in radians. */
/*     NTHDEC      I   Northern most declination in radians. */
/*     NSTARS      O   Number of stars found. */

/* $ Detailed_Input */

/*     CATNAM      is name of the catalog data table. This name is */
/*                 returned by the catalog loader routine STCL01. */

/*     WESTRA      are right ascension and declination constraints */
/*     EASTRA      giving the western, eastern, southern and northern */
/*     STHDEC      boundaries of a search rectangle as follows: */
/*     NTHDEC */
/*                       RA  BETWEEN WESTRA  AND EASTRA  and */
/*                       DEC BETWEEN STHDEC AND NTHDEC */

/*                 where RA and DEC are the right ascension and */
/*                 declination of a star. WESTRA always represents */
/*                 "west" side of this rectangle and EASTRA -- the */
/*                 "east" side.  STHDEC represents the "south" side */
/*                 of the rectangle, NTHDEC represents the "north" */
/*                 side of the rectangle. */

/*                 For an observer standing on the surface */
/*                 of the earth at the equator, the west side of the */
/*                 rectangle ( the side associated with WESTRA) rises */
/*                 first. The east side (the side associated with */
/*                 EASTRA) rises last.  All meridians that rise between */
/*                 the rising of the west and east edges of the */
/*                 rectangle  cross through the RA-DEC rectangle. */

/*                 To specify the 6 degrees wide RA-DEC */
/*                 square centered on the celestical equator that */
/*                 has western most right ascension of 357 degrees, */
/*                 use the following values for WESTRA, EASTRA, STHDEC, */
/*                 and NTHDEC (we multiply the angles by the SPICELIB */
/*                 function RPD to convert degrees to radians). */

/*                      WESTRA  = 357.0D0 * RPD() */
/*                      EASTRA  =   3.0D0 * RPD() */
/*                      STHDEC  =  -3.0D0 * RPD() */
/*                      DEXMAX  =   3.0D0 * RPD() */

/*                 To specify a 5 degree wide RA-DEC square that has */
/*                 western most right ascension 10 degrees and */
/*                 eastern most right ascension 15 degrees and southern */
/*                 most declination of 45 degrees, assign the following */
/*                 values to WESTRA, EASTRA, STHDEC and NTHDEC. */

/*                      WESTRA  =  10.0D0 * RPD() */
/*                      EASTRA  =  15.0D0 * RPD() */
/*                      STHDEC  =  45.0D0 * RPD() */
/*                      DEXMAX  =  50.0D0 * RPD() */

/*                 All RA and DECS should be in radians and relative */
/*                 to the J2000 inertial frame. */

/*                 All Right Ascension values should be in the */
/*                 interval [0, 2*pi ).  This routine does */
/*                 not "fold" Right Ascension values into the this */
/*                 interval.  For example if you request stars in */
/*                 whose right ascensions lie between 3*pi and 4*pi */
/*                 no stars will be found. */

/*                 All Declination values should be in the interval */
/*                 [-pi,pi]. */

/* $ Detailed_Output */

/*     NSTARS      is number of catalog stars found within the */
/*                 specified RA - DEC rectangle. */

/* $ Parameters */

/*     None. */

/* $ Exceptions */

/*     1) If no star catalog has been loaded, an error will be */
/*        signalled by a routine in the call tree of this routine. */

/*     2) If the catalog query fails for any reason then */
/*        the error 'SPICE(QUERYFAILURE)'is signalled. */

/* $ Files */

/*     This routine searches for stars within SPICE type 1 star catalog */
/*     files that have been loaded by calls to the STCL01 routine and */
/*     that contain that catalog data table named CATNAM. */

/*     SPICE type 1 star catalog files MUST contain a single data table. */
/*     It can occupy a single segment or it can spread across multiple */
/*     segments. This table MUST include the following columns: */

/*        column name                data type          units */
/*     ------------------------------------------------------- */
/*        RA                   DOUBLE PRECISION        DEGREES */
/*        DEC                  DOUBLE PRECISION        DEGREES */
/*        RA_SIGMA             DOUBLE PRECISION        DEGREES */
/*        DEC_SIGMA            DOUBLE PRECISION        DEGREES */
/*        CATALOG_NUMBER       INTEGER */
/*        SPECTRAL_TYPE        CHARACTER*(4) */
/*        VISUAL_MAGNITUDE     DOUBLE PRECISION */

/*     Nulls are not allowed in any of the columns. */
/*     Other columns can also be present in the table but their data */
/*     will NOT be accessible through STCF01 and STCG01 -- */
/*     the interface used to access data in the catalog. Note */
/*     that the names and attributes of these additional columns */
/*     must be identical for all segments containing this table. */

/* $ Particulars */

/*     This routine is intended to be a part of the user interface to */
/*     the SPICE type 1 star catalog. It allows the caller to find all */
/*     stars within a specified RA - DEC rectangle in the SPICE */
/*     EK type 1 star catalog files loaded by STCL01. This */
/*     subroutine MUST NOT be called before a catalog file has */
/*     been loaded. */

/*     Other routines in the SPICE type 1 star catalog access */
/*     family are: */

/*        STCL01  load the catalog file and make its data */
/*                available for search and retrieval. */

/*        STCG01  retrieve position and characteristics for */
/*                a specified star in the set found by this */
/*                routine. */

/* $ Examples */

/*     In the following code fragment, STCF01 is used to find */
/*     all stars within a specified RA - DEC rectangle in a SPICE */
/*     EK type 1 star catalog. */

/*     C */
/*     C     Load catalog file. */
/*     C */
/*           CALL STCL01 ( CATFN, TABNAM, HANDLE ) */
/*     C */
/*     C     Search through the loaded catalog. */
/*     C */
/*           CALL STCF01 ( TABNAM, WESTRA,  EASTRA, */
/*          .              STHDEC, NTHDEC, NSTARS ) */
/*     C */
/*     C     Retrieve data for every star found. */
/*     C */
/*           DO I = 1, NSTARS */

/*              CALL STCG01 ( I, RA, DEC, RASIG, DECSIG, */
/*          .                 CATNUM, SPTYPE, VMAG ) */

/*           END DO */

/* $ Restrictions */

/*     1) The catalog file STCF01 searches through MUST be loaded */
/*        by STCL01 before STCF01 is called. */

/* $ Literature_References */

/*     None. */

/* $ Author_and_Institution */

/*     B.V. Semenov    (JPL) */

/* $ Version */

/* -    SPICELIB Version 1.0.0, 15-MAY-1996 (BVS) */

/* -& */
/* $ Index_Entries */

/*      find stars in RA-DEC rectangle in type 1 star catalog */

/* -& */


/*     SPICELIB functions */


/*     Local parameters. */


/*     Local variables */


/*     Standard SPICE error handling. */

    if (return_()) {
	return 0;
    } else {
	chkin_("STCF01", (ftnlen)6);
    }

/*     Query templates. */

    s_copy(qrytm1, "SELECT RA, DEC, RA_SIGMA, DEC_SIGMA,CATALOG_NUMBER, SPEC"
	    "TRAL_TYPE, VISUAL_MAGNITUDE FROM # WHERE ( RA  BETWEEN # AND # )"
	    " AND ( DEC BETWEEN # AND # ) ", (ftnlen)512, (ftnlen)149);
    s_copy(qrytm2, "SELECT RA, DEC, RA_SIGMA, DEC_SIGMA,CATALOG_NUMBER, SPEC"
	    "TRAL_TYPE, VISUAL_MAGNITUDE FROM # WHERE ( ( RA BETWEEN # AND 36"
	    "0 ) OR   ( RA BETWEEN 0 AND #   )      ) AND   ( DEC BETWEEN # A"
	    "ND # ) ", (ftnlen)512, (ftnlen)191);

/*     Choose query template to be used. */

    if (*westra <= *eastra) {
	s_copy(query, qrytm1, (ftnlen)512, (ftnlen)512);
    } else {
	s_copy(query, qrytm2, (ftnlen)512, (ftnlen)512);
    }

/*     Convert angles in radians to angles in degrees. */

    ramin = *westra * dpr_();
    ramax = *eastra * dpr_();
    decmin = *sthdec * dpr_();
    decmax = *nthdec * dpr_();

/*     Construct query using inputs and chosen template. */

    repmc_(query, "#", catnam, query, (ftnlen)512, (ftnlen)1, catnam_len, (
	    ftnlen)512);
    repmd_(query, "#", &ramin, &c__15, query, (ftnlen)512, (ftnlen)1, (ftnlen)
	    512);
    repmd_(query, "#", &ramax, &c__15, query, (ftnlen)512, (ftnlen)1, (ftnlen)
	    512);
    repmd_(query, "#", &decmin, &c__15, query, (ftnlen)512, (ftnlen)1, (
	    ftnlen)512);
    repmd_(query, "#", &decmax, &c__15, query, (ftnlen)512, (ftnlen)1, (
	    ftnlen)512);

/*     Submit query and get number of stars. Check for */
/*     errors in QUERY. */

    ekfind_(query, nstars, &error, errmsg, (ftnlen)512, (ftnlen)512);
    if (error) {
	setmsg_("Error querying type 1 star catalog. Error message: # ", (
		ftnlen)53);
	errch_("#", errmsg, (ftnlen)1, (ftnlen)512);
	sigerr_("SPICE(QUERYFAILURE)", (ftnlen)19);
	chkout_("STCF01", (ftnlen)6);
	return 0;
    }
    chkout_("STCF01", (ftnlen)6);
    return 0;
} /* stcf01_ */
예제 #2
0
/* $Procedure      SPKE15 ( Evaluate a type 15 SPK data record) */
/* Subroutine */ int spke15_(doublereal *et, doublereal *recin, doublereal *
                             state)
{
    /* System generated locals */
    doublereal d__1;

    /* Builtin functions */
    double sqrt(doublereal), d_mod(doublereal *, doublereal *), d_sign(
        doublereal *, doublereal *);

    /* Local variables */
    doublereal near__, dmdt;
    extern /* Subroutine */ int vscl_(doublereal *, doublereal *, doublereal *
                                     );
    extern doublereal vdot_(doublereal *, doublereal *), vsep_(doublereal *,
            doublereal *);
    extern /* Subroutine */ int vequ_(doublereal *, doublereal *);
    integer j2flg;
    doublereal p, angle, dnode, z__;
    extern /* Subroutine */ int chkin_(char *, ftnlen);
    doublereal epoch, speed, dperi, theta, manom;
    extern /* Subroutine */ int moved_(doublereal *, integer *, doublereal *),
           errdp_(char *, doublereal *, ftnlen), vcrss_(doublereal *,
                   doublereal *, doublereal *);
    extern doublereal twopi_(void);
    extern logical vzero_(doublereal *);
    extern /* Subroutine */ int vrotv_(doublereal *, doublereal *, doublereal
                                       *, doublereal *);
    doublereal oneme2, state0[6];
    extern /* Subroutine */ int prop2b_(doublereal *, doublereal *,
                                        doublereal *, doublereal *);
    doublereal pa[3], gm, ta, dt;
    extern doublereal pi_(void);
    doublereal tp[3], pv[3], cosinc;
    extern /* Subroutine */ int sigerr_(char *, ftnlen), vhatip_(doublereal *)
    , chkout_(char *, ftnlen), vsclip_(doublereal *, doublereal *),
    setmsg_(char *, ftnlen);
    doublereal tmpsta[6], oj2;
    extern logical return_(void);
    doublereal ecc;
    extern doublereal dpr_(void);
    doublereal dot, rpl, k2pi;

    /* $ Abstract */

    /*     Evaluates a single SPK data record from a segment of type 15 */
    /*    (Precessing Conic Propagation). */

    /* $ 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 */

    /*     SPK */

    /* $ Keywords */

    /*     EPHEMERIS */

    /* $ Declarations */
    /* $ Brief_I/O */

    /*     Variable  I/O  Description */
    /*     --------  ---  -------------------------------------------------- */
    /*     ET         I   Target epoch. */
    /*     RECIN      I   Data record. */
    /*     STATE      O   State (position and velocity). */

    /* $ Detailed_Input */

    /*     ET          is a target epoch, specified as ephemeris seconds past */
    /*                 J2000, at which a state vector is to be computed. */

    /*     RECIN       is a data record which, when evaluated at epoch ET, */
    /*                 will give the state (position and velocity) of some */
    /*                 body, relative to some center, in some inertial */
    /*                 reference frame. */

    /*                 The structure of RECIN is: */

    /*                 RECIN(1)             epoch of periapsis */
    /*                                      in ephemeris seconds past J2000. */
    /*                 RECIN(2)-RECIN(4)    unit trajectory pole vector */
    /*                 RECIN(5)-RECIN(7)    unit periapsis vector */
    /*                 RECIN(8)             semi-latus rectum---p in the */
    /*                                      equation: */

    /*                                      r = p/(1 + ECC*COS(Nu)) */

    /*                 RECIN(9)             eccentricity */
    /*                 RECIN(10)            J2 processing flag describing */
    /*                                      what J2 corrections are to be */
    /*                                      applied when the orbit is */
    /*                                      propagated. */

    /*                                      All J2 corrections are applied */
    /*                                      if this flag has a value that */
    /*                                      is not 1,2 or 3. */

    /*                                      If the value of the flag is 3 */
    /*                                      no corrections are done. */

    /*                                      If the value of the flag is 1 */
    /*                                      no corrections are computed for */
    /*                                      the precession of the line */
    /*                                      of apsides.  However, regression */
    /*                                      of the line of nodes is */
    /*                                      performed. */

    /*                                      If the value of the flag is 2 */
    /*                                      no corrections are done for */
    /*                                      the regression of the line of */
    /*                                      nodes. However, precession of the */
    /*                                      line of apsides is performed. */

    /*                                      Note that J2 effects are computed */
    /*                                      only if the orbit is elliptic and */
    /*                                      does not intersect the central */
    /*                                      body. */

    /*                 RECIN(11)-RECIN(13)  unit central body pole vector */
    /*                 RECIN(14)            central body GM */
    /*                 RECIN(15)            central body J2 */
    /*                 RECIN(16)            central body radius */

    /*                 Units are radians, km, seconds */

    /* $ Detailed_Output */

    /*     STATE       is the state produced by evaluating RECIN at ET. */
    /*                 Units are km and km/sec. */

    /* $ Parameters */

    /*      None. */

    /* $ Files */

    /*      None. */

    /* $ Exceptions */

    /*     1) If the eccentricity is less than zero, the error */
    /*        'SPICE(BADECCENTRICITY)' will be signalled. */

    /*     2) If the semi-latus rectum is non-positive, the error */
    /*        'SPICE(BADLATUSRECTUM)' is signalled. */

    /*     3) If the pole vector, trajectory pole vector or periapsis vector */
    /*        has zero length, the error 'SPICE(BADVECTOR)' is signalled. */

    /*     4) If the trajectory pole vector and the periapsis vector are */
    /*        not orthogonal, the error 'SPICE(BADINITSTATE)' is */
    /*        signalled.  The test for orthogonality is very crude.  The */
    /*        routine simply checks that the absolute value of the dot */
    /*        product of the unit vectors parallel to the trajectory pole */
    /*        and periapse vectors is less than 0.00001.  This check is */
    /*        intended to catch blunders, not to enforce orthogonality to */
    /*        double precision tolerance. */

    /*     5) If the mass of the central body is non-positive, the error */
    /*       'SPICE(NONPOSITIVEMASS)' is signalled. */

    /*     6) If the radius of the central body is negative, the error */
    /*       'SPICE(BADRADIUS)' is signalled. */

    /* $ Particulars */

    /*     This algorithm applies J2 corrections for precessing the */
    /*     node and argument of periapse for an object orbiting an */
    /*     oblate spheroid. */

    /*     Note the effects of J2 are incorporated only for elliptic */
    /*     orbits that do not intersect the central body. */

    /*     While the derivation of the effect of the various harmonics */
    /*     of gravitational field are beyond the scope of this header */
    /*     the effect of the J2 term of the gravity model are as follows */


    /*        The line of node precesses. Over one orbit average rate of */
    /*        precession,  DNode/dNu,  is given by */

    /*                                3 J2 */
    /*              dNode/dNu =  -  -----------------  DCOS( inc ) */
    /*                                2 (P/RPL)**2 */

    /*        (Since this is always less than zero for oblate spheroids, this */
    /*           should be called regression of nodes.) */

    /*        The line of apsides precesses. The average rate of precession */
    /*        DPeri/dNu is given by */
    /*                                   3 J2 */
    /*              dPeri/dNu =     ----------------- ( 5*DCOS ( inc ) - 1 ) */
    /*                                2 (P/RPL)**2 */

    /*        Details of these formulae are given in the Battin's book (see */
    /*        literature references below). */


    /*     It is assumed that this routine is used in conjunction with */
    /*     the routine SPKR15 as shown here: */

    /*        CALL SPKR15 ( HANDLE, DESCR, ET, RECIN         ) */
    /*        CALL SPKE15 (                ET, RECIN, STATE  ) */

    /*     where it is known in advance that the HANDLE, DESCR pair points */
    /*     to a type 15 data segment. */

    /* $ Examples */

    /*     The SPKEnn routines are almost always used in conjunction with */
    /*     the corresponding SPKRnn routines, which read the records from */
    /*     SPK files. */

    /*     The data returned by the SPKRnn routine is in its rawest form, */
    /*     taken directly from the segment.  As such, it will be meaningless */
    /*     to a user unless he/she understands the structure of the data type */
    /*     completely.  Given that understanding, however, the SPKRnn */
    /*     routines might be used to examine raw segment data before */
    /*     evaluating it with the SPKEnn routines. */


    /*     C */
    /*     C     Get a segment applicable to a specified body and epoch. */
    /*     C */
    /*           CALL SPKSFS ( BODY, ET, HANDLE, DESCR, IDENT, FOUND ) */

    /*     C */
    /*     C     Look at parts of the descriptor. */
    /*     C */
    /*           CALL DAFUS ( DESCR, 2, 6, DCD, ICD ) */
    /*           CENTER = ICD( 2 ) */
    /*           REF    = ICD( 3 ) */
    /*           TYPE   = ICD( 4 ) */

    /*           IF ( TYPE .EQ. 15 ) THEN */

    /*              CALL SPKR15 ( HANDLE, DESCR, ET, RECORD ) */
    /*                  . */
    /*                  .  Look at the RECORD data. */
    /*                  . */
    /*              CALL SPKE15 ( ET, RECORD, STATE ) */
    /*                  . */
    /*                  .  Check out the evaluated state. */
    /*                  . */
    /*           END IF */

    /* $ Restrictions */

    /*     None. */

    /* $ Author_and_Institution */

    /*      K.R. Gehringer  (JPL) */
    /*      S.   Schlaifer  (JPL) */
    /*      W.L. Taber      (JPL) */

    /* $ Literature_References */

    /*     [1] `Fundamentals of Celestial Mechanics', Second Edition 1989 */
    /*         by J.M.A. Danby;  Willman-Bell, Inc., P.O. Box 35025 */
    /*         Richmond Virginia;  pp 345-347. */

    /*     [2] `Astronautical Guidance', by Richard H. Battin. 1964 */
    /*          McGraw-Hill Book Company, San Francisco.  pp 199 */

    /* $ Version */

    /* -    SPICELIB Version 1.2.0, 02-SEP-2005 (NJB) */

    /*        Updated to remove non-standard use of duplicate arguments */
    /*        in VHAT, VROTV, and VSCL calls. */

    /* -    SPICELIB Version 1.1.0, 29-FEB-1996 (KRG) */

    /*        The declaration for the SPICELIB function PI is now */
    /*        preceded by an EXTERNAL statement declaring PI to be an */
    /*        external function. This removes a conflict with any */
    /*        compilers that have a PI intrinsic function. */

    /* -    SPICELIB Version 1.0.0, 15-NOV-1994 (WLT) (SS) */

    /* -& */
    /* $ Index_Entries */

    /*     evaluate type_15 spk segment */

    /* -& */
    /* $ Revisions */

    /* -    SPICELIB Version 1.2.0, 02-SEP-2005 (NJB) */

    /*        Updated to remove non-standard use of duplicate arguments */
    /*        in VHAT, VROTV, and VSCL calls. */

    /* -    SPICELIB Version 1.1.0, 29-FEB-1996 (KRG) */

    /*        The declaration for the SPICELIB function PI is now */
    /*        preceded by an EXTERNAL statement declaring PI to be an */
    /*        external function. This removes a conflict with any */
    /*        compilers that have a PI intrinsic function. */

    /* -    SPICELIB Version 1.0.0, 15-NOV-1994 (WLT) (SS) */

    /* -& */

    /*     SPICELIB Functions */


    /*     Local Variables */


    /*     Standard SPICE error handling. */

    if (return_()) {
        return 0;
    }
    chkin_("SPKE15", (ftnlen)6);

    /*     Fetch the various entities from the input record, first the epoch. */

    epoch = recin[0];

    /*     The trajectory pole vector. */

    vequ_(&recin[1], tp);

    /*     The periapsis vector. */

    vequ_(&recin[4], pa);

    /*     Semi-latus rectum ( P in the P/(1 + ECC*COS(Nu)  ), */
    /*     and eccentricity. */

    p = recin[7];
    ecc = recin[8];

    /*     J2 processing flag. */

    j2flg = (integer) recin[9];

    /*     Central body pole vector. */

    vequ_(&recin[10], pv);

    /*     The central mass, J2 and radius of the central body. */

    gm = recin[13];
    oj2 = recin[14];
    rpl = recin[15];

    /*     Check all the inputs here for obvious failures.  Yes, perhaps */
    /*     this is overkill.  However, there is a lot more computation */
    /*     going on in this routine so that the small amount of overhead */
    /*     here should not be significant. */

    if (p <= 0.) {
        setmsg_("The semi-latus rectum supplied to the SPK type 15 evaluator"
                " was non-positive.  This value must be positive. The value s"
                "upplied was #.", (ftnlen)133);
        errdp_("#", &p, (ftnlen)1);
        sigerr_("SPICE(BADLATUSRECTUM)", (ftnlen)21);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    } else if (ecc < 0.) {
        setmsg_("The eccentricity supplied for a type 15 segment is negative"
                ".  It must be non-negative. The value supplied to the type 1"
                "5 evaluator was #. ", (ftnlen)138);
        errdp_("#", &ecc, (ftnlen)1);
        sigerr_("SPICE(BADECCENTRICITY)", (ftnlen)22);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    } else if (gm <= 0.) {
        setmsg_("The mass supplied for the central body of a type 15 segment"
                " was non-positive. Masses must be positive.  The value suppl"
                "ied was #. ", (ftnlen)130);
        errdp_("#", &gm, (ftnlen)1);
        sigerr_("SPICE(NONPOSITIVEMASS)", (ftnlen)22);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    } else if (vzero_(tp)) {
        setmsg_("The trajectory pole vector supplied to SPKE15 had length ze"
                "ro. The most likely cause of this problem is a corrupted SPK"
                " (ephemeris) file. ", (ftnlen)138);
        sigerr_("SPICE(BADVECTOR)", (ftnlen)16);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    } else if (vzero_(pa)) {
        setmsg_("The periapse vector supplied to SPKE15 had length zero. The"
                " most likely cause of this problem is a corrupted SPK (ephem"
                "eris) file. ", (ftnlen)131);
        sigerr_("SPICE(BADVECTOR)", (ftnlen)16);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    } else if (vzero_(pv)) {
        setmsg_("The central pole vector supplied to SPKE15 had length zero."
                " The most likely cause of this problem is a corrupted SPK (e"
                "phemeris) file. ", (ftnlen)135);
        sigerr_("SPICE(BADVECTOR)", (ftnlen)16);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    } else if (rpl < 0.) {
        setmsg_("The central body radius was negative. It must be zero or po"
                "sitive.  The value supplied was #. ", (ftnlen)94);
        errdp_("#", &rpl, (ftnlen)1);
        sigerr_("SPICE(BADRADIUS)", (ftnlen)16);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    }

    /*     Convert TP, PV and PA to unit vectors. */
    /*     (It won't hurt to polish them up a bit here if they are already */
    /*      unit vectors.) */

    vhatip_(pa);
    vhatip_(tp);
    vhatip_(pv);

    /*     One final check.  Make sure the pole and periapse vectors are */
    /*     orthogonal. (We will use a very crude check but this should */
    /*     rule out any obvious errors.) */

    dot = vdot_(pa, tp);
    if (abs(dot) > 1e-5) {
        angle = vsep_(pa, tp) * dpr_();
        setmsg_("The periapsis and trajectory pole vectors are not orthogona"
                "l. The anglebetween them is # degrees. ", (ftnlen)98);
        errdp_("#", &angle, (ftnlen)1);
        sigerr_("SPICE(BADINITSTATE)", (ftnlen)19);
        chkout_("SPKE15", (ftnlen)6);
        return 0;
    }

    /*     Compute the distance and speed at periapse. */

    near__ = p / (ecc + 1.);
    speed = sqrt(gm / p) * (ecc + 1.);

    /*     Next get the position at periapse ... */

    vscl_(&near__, pa, state0);

    /*     ... and the velocity at periapsis. */

    vcrss_(tp, pa, &state0[3]);
    vsclip_(&speed, &state0[3]);

    /*     Determine the elapsed time from periapse to the requested */
    /*     epoch and propagate the state at periapsis to the epoch of */
    /*     interest. */

    /*     Note that we are making use of the following fact. */

    /*        If R is a rotation, then the states obtained by */
    /*        the following blocks of code are mathematically the */
    /*        same. (In reality they may differ slightly due to */
    /*        roundoff.) */

    /*        Code block 1. */

    /*           CALL MXV   ( R,  STATE0,     STATE0    ) */
    /*           CALL MXV   ( R,  STATE0(4),  STATE0(4) ) */
    /*           CALL PROP2B( GM, STATE0, DT, STATE     ) */

    /*        Code block 2. */

    /*           CALL PROP2B( GM, STATE0, DT, STATE    ) */
    /*           CALL MXV   ( R,  STATE,      STATE    ) */
    /*           CALL MXV   ( R,  STATE(4),   STATE(4) ) */


    /*     This allows us to first compute the propagation of our initial */
    /*     state and then if needed perform the precession of the line */
    /*     of nodes and apsides by simply precessing the resulting state. */

    dt = *et - epoch;
    prop2b_(&gm, state0, &dt, state);

    /*     If called for, handle precession needed due to the J2 term.  Note */
    /*     that the motion of the lines of nodes and apsides is formulated */
    /*     in terms of the true anomaly.  This means we need the accumulated */
    /*     true anomaly in order to properly transform the state. */

    if (j2flg != 3 && oj2 != 0. && ecc < 1. && near__ > rpl) {

        /*        First compute the change in mean anomaly since periapsis. */

        /* Computing 2nd power */
        d__1 = ecc;
        oneme2 = 1. - d__1 * d__1;
        dmdt = oneme2 / p * sqrt(gm * oneme2 / p);
        manom = dmdt * dt;

        /*        Next compute the angle THETA such that THETA is between */
        /*        -pi and pi and such than MANOM = THETA + K*2*pi for */
        /*        some integer K. */

        d__1 = twopi_();
        theta = d_mod(&manom, &d__1);
        if (abs(theta) > pi_()) {
            d__1 = twopi_();
            theta -= d_sign(&d__1, &theta);
        }
        k2pi = manom - theta;

        /*        We can get the accumulated true anomaly from the propagated */
        /*        state theta and the accumulated mean anomaly prior to this */
        /*        orbit. */

        ta = vsep_(pa, state);
        ta = d_sign(&ta, &theta);
        ta += k2pi;

        /*        Determine how far the line of nodes and periapsis have moved. */

        cosinc = vdot_(pv, tp);
        /* Computing 2nd power */
        d__1 = rpl / p;
        z__ = ta * 1.5 * oj2 * (d__1 * d__1);
        dnode = -z__ * cosinc;
        /* Computing 2nd power */
        d__1 = cosinc;
        dperi = z__ * (d__1 * d__1 * 2.5 - .5);

        /*        Precess the periapsis by rotating the state vector about the */
        /*        trajectory pole */

        if (j2flg != 1) {
            vrotv_(state, tp, &dperi, tmpsta);
            vrotv_(&state[3], tp, &dperi, &tmpsta[3]);
            moved_(tmpsta, &c__6, state);
        }

        /*        Regress the line of nodes by rotating the state */
        /*        about the pole of the central body. */

        if (j2flg != 2) {
            vrotv_(state, pv, &dnode, tmpsta);
            vrotv_(&state[3], pv, &dnode, &tmpsta[3]);
            moved_(tmpsta, &c__6, state);
        }

        /*        We could perform the rotations above in the other order, */
        /*        but we would also have to rotate the pole before precessing */
        /*        the line of apsides. */

    }

    /*     That's all folks.  Check out and return. */

    chkout_("SPKE15", (ftnlen)6);
    return 0;
} /* spke15_ */
예제 #3
0
파일: spkw15.c 프로젝트: Dbelsa/coft
/* $Procedure      SPKW15 ( SPK, write a type 15 segment ) */
/* Subroutine */ int spkw15_(integer *handle, integer *body, integer *center, 
	char *frame, doublereal *first, doublereal *last, char *segid, 
	doublereal *epoch, doublereal *tp, doublereal *pa, doublereal *p, 
	doublereal *ecc, doublereal *j2flg, doublereal *pv, doublereal *gm, 
	doublereal *j2, doublereal *radius, ftnlen frame_len, ftnlen 
	segid_len)
{
    /* System generated locals */
    integer i__1;

    /* Local variables */
    extern /* Subroutine */ int vhat_(doublereal *, doublereal *);
    doublereal mypa[3];
    extern doublereal vdot_(doublereal *, doublereal *), vsep_(doublereal *, 
	    doublereal *);
    extern /* Subroutine */ int vequ_(doublereal *, doublereal *);
    doublereal mytp[3];
    integer i__;
    doublereal angle;
    extern /* Subroutine */ int chkin_(char *, ftnlen);
    doublereal descr[5];
    integer value;
    extern /* Subroutine */ int errdp_(char *, doublereal *, ftnlen);
    extern logical vzero_(doublereal *);
    extern /* Subroutine */ int dafada_(doublereal *, integer *), dafbna_(
	    integer *, doublereal *, char *, ftnlen), dafena_(void);
    extern logical failed_(void);
    doublereal record[16];
    extern integer lastnb_(char *, ftnlen);
    extern /* Subroutine */ int sigerr_(char *, ftnlen), chkout_(char *, 
	    ftnlen), setmsg_(char *, ftnlen), errint_(char *, integer *, 
	    ftnlen), spkpds_(integer *, integer *, char *, integer *, 
	    doublereal *, doublereal *, doublereal *, ftnlen);
    extern logical return_(void);
    extern doublereal dpr_(void);
    doublereal dot;

/* $ Abstract */

/*     Write an SPK segment of type 15 given a type 15 data record. */

/* $ 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 */

/*     SPK */

/* $ Keywords */

/*     EPHEMERIS */

/* $ Declarations */
/* $ Brief_I/O */

/*     Variable  I/O  Description */
/*     --------  ---  -------------------------------------------------- */
/*     HANDLE     I   Handle of an SPK file open for writing. */
/*     BODY       I   Body code for ephemeris object. */
/*     CENTER     I   Body code for the center of motion of the body. */
/*     FRAME      I   The reference frame of the states. */
/*     FIRST      I   First valid time for which states can be computed. */
/*     LAST       I   Last valid time for which states can be computed. */
/*     SEGID      I   Segment identifier. */
/*     EPOCH      I   Epoch of the periapse. */
/*     TP         I   Trajectory pole vector. */
/*     PA         I   Periapsis vector. */
/*     P          I   Semi-latus rectum. */
/*     ECC        I   Eccentricity. */
/*     J2FLG      I   J2 processing flag. */
/*     PV         I   Central body pole vector. */
/*     GM         I   Central body GM. */
/*     J2         I   Central body J2. */
/*     RADIUS     I   Equatorial radius of central body. */

/* $ Detailed_Input */

/*     HANDLE      is the file handle of an SPK file that has been */
/*                 opened for writing. */

/*     BODY        is the NAIF ID for the body whose states are */
/*                 to be recorded in an SPK file. */

/*     CENTER      is the NAIF ID for the center of motion associated */
/*                 with BODY. */

/*     FRAME       is the reference frame that states are referenced to, */
/*                 for example 'J2000'. */

/*     FIRST       are the bounds on the ephemeris times, expressed as */
/*     LAST        seconds past J2000. */

/*     SEGID       is the segment identifier. An SPK segment identifier */
/*                 may contain up to 40 characters. */

/*     EPOCH       is the epoch of the orbit elements at periapse */
/*                 in ephemeris seconds past J2000. */

/*     TP          is a vector parallel to the angular momentum vector */
/*                 of the orbit at epoch expressed relative to FRAME. A */
/*                 unit vector parallel to TP will be stored in the */
/*                 output segment. */

/*     PA          is a vector parallel to the position vector of the */
/*                 trajectory at periapsis of EPOCH expressed relative */
/*                 to FRAME. A unit vector parallel to PA will be */
/*                 stored in the output segment. */

/*     P           is the semi-latus rectum--- p in the equation: */

/*                    r = p/(1 + ECC*COS(Nu)) */

/*     ECC          is the eccentricity. */

/*     J2FLG        is the J2 processing flag describing what J2 */
/*                  corrections are to be applied when the orbit is */
/*                  propagated. */

/*                  All J2 corrections are applied if the value of J2FLG */
/*                  is not 1, 2 or 3. */

/*                  If the value of the flag is 3 no corrections are */
/*                  done. */

/*                  If the value of the flag is 1 no corrections are */
/*                  computed for the precession of the line of apsides. */
/*                  However, regression of the line of nodes is */
/*                  performed. */

/*                  If the value of the flag is 2 no corrections are */
/*                  done for the regression of the line of nodes. */
/*                  However, precession of the line of apsides is */
/*                  performed. */

/*                  Note that J2 effects are computed only if the orbit */
/*                  is elliptic and does not intersect the central body. */

/*     PV           is a vector parallel to the north pole vector of the */
/*                  central body expressed relative to FRAME. A unit */
/*                  vector parallel to PV will be stored in the output */
/*                  segment. */

/*     GM           is the central body GM. */

/*     J2           is the central body J2 (dimensionless). */

/*     RADIUS       is the equatorial radius of the central body. */

/*     Units are radians, km, seconds. */

/* $ Detailed_Output */

/*     None.  A type 15 segment is written to the file attached */
/*     to HANDLE. */

/* $ Parameters */

/*     None. */

/* $ Exceptions */

/*     1) If the eccentricity is less than zero, the error */
/*        'SPICE(BADECCENTRICITY)' will be signaled. */

/*     2) If the semi-latus rectum is 0, the error */
/*        'SPICE(BADLATUSRECTUM)' is signaled. */

/*     3) If the pole vector, trajectory pole vector or periapsis vector */
/*        have zero length, the error 'SPICE(BADVECTOR)' is signaled. */

/*     4) If the trajectory pole vector and the periapsis vector are */
/*        not orthogonal, the error 'SPICE(BADINITSTATE)' is signaled. */
/*        The test for orthogonality is very crude.  The routine simply */
/*        checks that the dot product of the unit vectors parallel */
/*        to the trajectory pole and periapse vectors is less than */
/*        0.00001.  This check is intended to catch blunders, not to */
/*        enforce orthogonality to double precision capacity. */

/*     5) If the mass of the central body is non-positive, the error */
/*       'SPICE(NONPOSITIVEMASS)' is signaled. */

/*     6) If the radius of the central body is negative, the error */
/*       'SPICE(BADRADIUS)' is signaled. */

/*     7) If the segment identifier has more than 40 non-blank characters */
/*        the error 'SPICE(SEGIDTOOLONG)' is signaled. */

/*     8) If the segment identifier contains non-printing characters */
/*        the error 'SPICE(NONPRINTABLECHARS)' is signaled. */

/*     9) If there are inconsistencies in the BODY, CENTER, FRAME or */
/*        FIRST and LAST times, the problem will be diagnosed by */
/*        a routine in the call tree of this routine. */

/* $ Files */

/*     A new type 15 SPK segment is written to the SPK file attached */
/*     to HANDLE. */

/* $ Particulars */

/*     This routine writes an SPK type 15 data segment to the open SPK */
/*     file according to the format described in the type 15 section of */
/*     the SPK Required Reading. The SPK file must have been opened with */
/*     write access. */

/*     This routine is provided to provide direct support for the MASL */
/*     precessing orbit formulation. */

/* $ Examples */

/*     Suppose that at time EPOCH you have the J2000 periapsis */
/*     state of some object relative to some central body and would */
/*     like to create a type 15 SPK segment to model the motion of */
/*     the object using simple regression and precession of the */
/*     line of nodes and apsides. The following code fragment */
/*     illustrates how you can prepare such a segment.  We shall */
/*     assume that you have in hand the J2000 direction of the */
/*     central body's pole vector, its GM, J2 and equatorial */
/*     radius.  In addition we assume that you have opened an SPK */
/*     file for write access and that it is attached to HANDLE. */

/*    (If your state is at an epoch other than periapse the */
/*     fragment below will NOT produce a "correct" type 15 segment */
/*     for modeling the motion of your object.) */

/*     C */
/*     C     First we get the osculating elements. */
/*     C */
/*           CALL OSCELT ( STATE, EPOCH, GM, ELTS ) */

/*     C */
/*     C     From these collect the eccentricity and semi-latus rectum. */
/*     C */
/*           ECC = ELTS ( 2 ) */
/*           P   = ELTS ( 1 ) * ( 1.0D0 + ECC ) */
/*     C */
/*     C     Next get the trajectory pole vector and the */
/*     C     periapsis vector. */
/*     C */
/*           CALL UCRSS ( STATE(1), STATE(4), TP ) */
/*           CALL VHAT  ( STATE(1),           PA ) */

/*     C */
/*     C     Enable both J2 corrections. */
/*     C */

/*          J2FLG = 0.0D0 */

/*     C */
/*     C     Now add the segment. */
/*     C */

/*           CALL SPKW15 ( HANDLE, BODY,  CENTER, FRAME,  FIRST, LAST, */
/*           .              SEGID,  EPOCH, TP,     PA,    P,     ECC, */
/*           .              J2FLG,  PV,    GM,     J2,    RADIUS      ) */


/* $ Restrictions */

/*     None. */

/* $ Literature_References */

/*     None. */

/* $ Author_and_Institution */

/*     N.J. Bachman    (JPL) */
/*     W.L. Taber      (JPL) */

/* $ Version */

/* -    SPICELIB Version 2.0.0, 29-MAY-2012 (NJB) */

/*        Input vectors that nominally have unit length */
/*        are mapped to local copies that actually do */
/*        have unit length. The applicable inputs are TP, PA, */
/*        and PV. The Detailed Input header section was updated */
/*        to reflect the change. */

/*        Some typos in error messages were corrected. */

/* -    SPICELIB Version 1.0.0, 28-NOV-1994 (WLT) */

/* -& */
/* $ Index_Entries */

/*     Write a type 15 spk segment */

/* -& */

/*     SPICELIB Functions */


/*     Local Variables */


/*     Segment descriptor size */


/*     Segment identifier size */


/*     SPK data type */


/*     Range of printing characters */


/*     Number of items in a segment */


/*     Standard SPICE error handling. */

    if (return_()) {
	return 0;
    }
    chkin_("SPKW15", (ftnlen)6);

/*     Fetch the various entities from the inputs and put them into */
/*     the data record, first the epoch. */

    record[0] = *epoch;

/*     Convert TP and PA to unit vectors. */

    vhat_(pa, mypa);
    vhat_(tp, mytp);

/*     The trajectory pole vector. */

    vequ_(mytp, &record[1]);

/*     The periapsis vector. */

    vequ_(mypa, &record[4]);

/*     Semi-latus rectum ( P in the P/(1 + ECC*COS(Nu)  ), */
/*     and eccentricity. */

    record[7] = *p;
    record[8] = *ecc;

/*     J2 processing flag. */

    record[9] = *j2flg;

/*     Central body pole vector. */

    vhat_(pv, &record[10]);

/*     The central mass, J2 and radius of the central body. */

    record[13] = *gm;
    record[14] = *j2;
    record[15] = *radius;

/*     Check all the inputs here for obvious failures.  It's much */
/*     better to check them now and quit than it is to get a bogus */
/*     segment into an SPK file and diagnose it later. */

    if (*p <= 0.) {
	setmsg_("The semi-latus rectum supplied to the SPK type 15 evaluator"
		" was non-positive.  This value must be positive. The value s"
		"upplied was #.", (ftnlen)133);
	errdp_("#", p, (ftnlen)1);
	sigerr_("SPICE(BADLATUSRECTUM)", (ftnlen)21);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    } else if (*ecc < 0.) {
	setmsg_("The eccentricity supplied for a type 15 segment is negative"
		".  It must be non-negative. The value supplied to the type 1"
		"5 evaluator was #. ", (ftnlen)138);
	errdp_("#", ecc, (ftnlen)1);
	sigerr_("SPICE(BADECCENTRICITY)", (ftnlen)22);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    } else if (*gm <= 0.) {
	setmsg_("The mass supplied for the central body of a type 15 segment"
		" was non-positive. Masses must be positive.  The value suppl"
		"ied was #. ", (ftnlen)130);
	errdp_("#", gm, (ftnlen)1);
	sigerr_("SPICE(NONPOSITIVEMASS)", (ftnlen)22);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    } else if (vzero_(tp)) {
	setmsg_("The trajectory pole vector supplied to SPKW15 had length ze"
		"ro. The most likely cause of this problem is an uninitialize"
		"d vector.", (ftnlen)128);
	sigerr_("SPICE(BADVECTOR)", (ftnlen)16);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    } else if (vzero_(pa)) {
	setmsg_("The periapse vector supplied to SPKW15 had length zero. The"
		" most likely cause of this problem is an uninitialized vecto"
		"r.", (ftnlen)121);
	sigerr_("SPICE(BADVECTOR)", (ftnlen)16);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    } else if (vzero_(pv)) {
	setmsg_("The central pole vector supplied to SPKW15 had length zero."
		" The most likely cause of this problem is an uninitialized v"
		"ector. ", (ftnlen)126);
	sigerr_("SPICE(BADVECTOR)", (ftnlen)16);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    } else if (*radius < 0.) {
	setmsg_("The central body radius was negative. It must be zero or po"
		"sitive.  The value supplied was #. ", (ftnlen)94);
	errdp_("#", radius, (ftnlen)1);
	sigerr_("SPICE(BADRADIUS)", (ftnlen)16);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    }

/*     One final check.  Make sure the pole and periapse vectors are */
/*     orthogonal. (We will use a very crude check but this should */
/*     rule out any obvious errors.) */

    dot = vdot_(mypa, mytp);
    if (abs(dot) > 1e-5) {
	angle = vsep_(pa, tp) * dpr_();
	setmsg_("The periapsis and trajectory pole vectors are not orthogona"
		"l. The angle between them is # degrees. ", (ftnlen)99);
	errdp_("#", &angle, (ftnlen)1);
	sigerr_("SPICE(BADINITSTATE)", (ftnlen)19);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    }

/*     Make sure the segment identifier is not too long. */

    if (lastnb_(segid, segid_len) > 40) {
	setmsg_("Segment identifier contains more than 40 characters.", (
		ftnlen)52);
	sigerr_("SPICE(SEGIDTOOLONG)", (ftnlen)19);
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    }

/*     Make sure it has only printing characters. */

    i__1 = lastnb_(segid, segid_len);
    for (i__ = 1; i__ <= i__1; ++i__) {
	value = *(unsigned char *)&segid[i__ - 1];
	if (value < 32 || value > 126) {
	    setmsg_("The segment identifier contains the nonprintable charac"
		    "ter having ascii code #.", (ftnlen)79);
	    errint_("#", &value, (ftnlen)1);
	    sigerr_("SPICE(NONPRINTABLECHARS)", (ftnlen)24);
	    chkout_("SPKW15", (ftnlen)6);
	    return 0;
	}
    }

/*     All of the obvious checks have been performed on the input */
/*     record.  Create the segment descriptor. (FIRST and LAST are */
/*     checked by SPKPDS as well as consistency between BODY and CENTER). */

    spkpds_(body, center, frame, &c__15, first, last, descr, frame_len);
    if (failed_()) {
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    }

/*     Begin a new segment. */

    dafbna_(handle, descr, segid, segid_len);
    if (failed_()) {
	chkout_("SPKW15", (ftnlen)6);
	return 0;
    }
    dafada_(record, &c__16);
    if (! failed_()) {
	dafena_();
    }
    chkout_("SPKW15", (ftnlen)6);
    return 0;
} /* spkw15_ */