1 /* ckgp.f -- translated by f2c (version 19980913).
2 You must link the resulting object file with the libraries:
3 -lf2c -lm (in that order)
4 */
5
6 #include "f2c.h"
7
8 /* Table of constant values */
9
10 static integer c__2 = 2;
11 static integer c__6 = 6;
12 static integer c__9 = 9;
13
14 /* $Procedure CKGP ( C-kernel, get pointing ) */
ckgp_(integer * inst,doublereal * sclkdp,doublereal * tol,char * ref,doublereal * cmat,doublereal * clkout,logical * found,ftnlen ref_len)15 /* Subroutine */ int ckgp_(integer *inst, doublereal *sclkdp, doublereal *tol,
16 char *ref, doublereal *cmat, doublereal *clkout, logical *found,
17 ftnlen ref_len)
18 {
19 /* Initialized data */
20
21 static logical first = TRUE_;
22
23 logical pfnd, sfnd;
24 integer sclk;
25 extern /* Subroutine */ int sct2e_(integer *, doublereal *, doublereal *),
26 zznamfrm_(integer *, char *, integer *, char *, integer *,
27 ftnlen, ftnlen);
28 integer type1, type2;
29 extern /* Subroutine */ int zzctruin_(integer *);
30 char segid[40];
31 extern /* Subroutine */ int chkin_(char *, ftnlen);
32 doublereal descr[5];
33 extern /* Subroutine */ int dafus_(doublereal *, integer *, integer *,
34 doublereal *, integer *), ckbss_(integer *, doublereal *,
35 doublereal *, logical *), ckpfs_(integer *, doublereal *,
36 doublereal *, doublereal *, logical *, doublereal *, doublereal *,
37 doublereal *, logical *), moved_(doublereal *, integer *,
38 doublereal *), cksns_(integer *, doublereal *, char *, logical *,
39 ftnlen);
40 static char svref[32];
41 logical gotit;
42 static integer svctr1[2];
43 extern logical failed_(void);
44 doublereal av[3], et;
45 integer handle;
46 extern /* Subroutine */ int refchg_(integer *, integer *, doublereal *,
47 doublereal *);
48 logical needav;
49 extern /* Subroutine */ int ckmeta_(integer *, char *, integer *, ftnlen);
50 integer refseg, center;
51 extern /* Subroutine */ int frinfo_(integer *, integer *, integer *,
52 integer *, logical *);
53 integer refreq, typeid;
54 extern /* Subroutine */ int chkout_(char *, ftnlen);
55 doublereal tmpmat[9] /* was [3][3] */;
56 static integer svrefr;
57 extern logical return_(void);
58 doublereal dcd[2];
59 integer icd[6];
60 extern /* Subroutine */ int mxm_(doublereal *, doublereal *, doublereal *)
61 ;
62 doublereal rot[9] /* was [3][3] */;
63
64 /* $ Abstract */
65
66 /* Get pointing (attitude) for a specified spacecraft clock time. */
67
68 /* $ Disclaimer */
69
70 /* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
71 /* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
72 /* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
73 /* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
74 /* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
75 /* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
76 /* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
77 /* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
78 /* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
79 /* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
80
81 /* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
82 /* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
83 /* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
84 /* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
85 /* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
86 /* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
87
88 /* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
89 /* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
90 /* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
91 /* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
92
93 /* $ Required_Reading */
94
95 /* CK */
96 /* SCLK */
97
98 /* $ Keywords */
99
100 /* POINTING */
101
102 /* $ Declarations */
103 /* $ Abstract */
104
105 /* The parameters below form an enumerated list of the recognized */
106 /* frame types. They are: INERTL, PCK, CK, TK, DYN. The meanings */
107 /* are outlined below. */
108
109 /* $ Disclaimer */
110
111 /* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
112 /* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
113 /* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
114 /* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
115 /* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
116 /* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
117 /* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
118 /* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
119 /* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
120 /* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
121
122 /* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
123 /* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
124 /* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
125 /* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
126 /* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
127 /* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
128
129 /* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
130 /* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
131 /* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
132 /* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
133
134 /* $ Parameters */
135
136 /* INERTL an inertial frame that is listed in the routine */
137 /* CHGIRF and that requires no external file to */
138 /* compute the transformation from or to any other */
139 /* inertial frame. */
140
141 /* PCK is a frame that is specified relative to some */
142 /* INERTL frame and that has an IAU model that */
143 /* may be retrieved from the PCK system via a call */
144 /* to the routine TISBOD. */
145
146 /* CK is a frame defined by a C-kernel. */
147
148 /* TK is a "text kernel" frame. These frames are offset */
149 /* from their associated "relative" frames by a */
150 /* constant rotation. */
151
152 /* DYN is a "dynamic" frame. These currently are */
153 /* parameterized, built-in frames where the full frame */
154 /* definition depends on parameters supplied via a */
155 /* frame kernel. */
156
157 /* ALL indicates any of the above classes. This parameter */
158 /* is used in APIs that fetch information about frames */
159 /* of a specified class. */
160
161
162 /* $ Author_and_Institution */
163
164 /* N.J. Bachman (JPL) */
165 /* W.L. Taber (JPL) */
166
167 /* $ Literature_References */
168
169 /* None. */
170
171 /* $ Version */
172
173 /* - SPICELIB Version 4.0.0, 08-MAY-2012 (NJB) */
174
175 /* The parameter ALL was added to support frame fetch APIs. */
176
177 /* - SPICELIB Version 3.0.0, 28-MAY-2004 (NJB) */
178
179 /* The parameter DYN was added to support the dynamic frame class. */
180
181 /* - SPICELIB Version 2.0.0, 12-DEC-1996 (WLT) */
182
183 /* Various unused frames types were removed and the */
184 /* frame time TK was added. */
185
186 /* - SPICELIB Version 1.0.0, 10-DEC-1995 (WLT) */
187
188 /* -& */
189
190 /* End of INCLUDE file frmtyp.inc */
191
192 /* $ Abstract */
193
194 /* This include file defines the dimension of the counter */
195 /* array used by various SPICE subsystems to uniquely identify */
196 /* changes in their states. */
197
198 /* $ Disclaimer */
199
200 /* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
201 /* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
202 /* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
203 /* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
204 /* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
205 /* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
206 /* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
207 /* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
208 /* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
209 /* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
210
211 /* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
212 /* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
213 /* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
214 /* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
215 /* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
216 /* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
217
218 /* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
219 /* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
220 /* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
221 /* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
222
223 /* $ Parameters */
224
225 /* CTRSIZ is the dimension of the counter array used by */
226 /* various SPICE subsystems to uniquely identify */
227 /* changes in their states. */
228
229 /* $ Author_and_Institution */
230
231 /* B.V. Semenov (JPL) */
232
233 /* $ Literature_References */
234
235 /* None. */
236
237 /* $ Version */
238
239 /* - SPICELIB Version 1.0.0, 29-JUL-2013 (BVS) */
240
241 /* -& */
242
243 /* End of include file. */
244
245 /* $ Brief_I/O */
246
247 /* Variable I/O Description */
248 /* -------- --- -------------------------------------------------- */
249 /* INST I NAIF ID of instrument, spacecraft, or structure. */
250 /* SCLKDP I Encoded spacecraft clock time. */
251 /* TOL I Time tolerance. */
252 /* REF I Reference frame. */
253 /* CMAT O C-matrix pointing data. */
254 /* CLKOUT O Output encoded spacecraft clock time. */
255 /* FOUND O True when requested pointing is available. */
256
257 /* $ Detailed_Input */
258
259 /* INST is the NAIF integer ID for the instrument, spacecraft, */
260 /* or other structure for which pointing is requested. */
261 /* For brevity we will refer to this object as the */
262 /* "instrument," and the frame fixed to this object as */
263 /* the "instrument frame" or "instrument-fixed" frame. */
264
265 /* SCLKDP is the encoded spacecraft clock time for which */
266 /* pointing is requested. */
267
268 /* The SPICELIB routines SCENCD and SCE2C respectively */
269 /* convert spacecraft clock strings and ephemeris time to */
270 /* encoded spacecraft clock. The inverse conversions are */
271 /* performed by SCDECD and SCT2E. */
272
273 /* TOL is a time tolerance in ticks, the units of encoded */
274 /* spacecraft clock time. */
275
276 /* The SPICELIB routine SCTIKS converts a spacecraft */
277 /* clock tolerance duration from its character string */
278 /* representation to ticks. SCFMT performs the inverse */
279 /* conversion. */
280
281 /* The C-matrix returned by CKGP is the one whose time */
282 /* tag is closest to SCLKDP and within TOL units of */
283 /* SCLKDP. (More in Particulars, below.) */
284
285 /* In general, because using a non-zero tolerance */
286 /* affects selection of the segment from which the */
287 /* data is obtained, users are strongly discouraged */
288 /* from using a non-zero tolerance when reading CKs */
289 /* with continuous data. Using a non-zero tolerance */
290 /* should be reserved exclusively to reading CKs with */
291 /* discrete data because in practice obtaining data */
292 /* from such CKs using a zero tolerance is often not */
293 /* possible due to time round off. */
294
295 /* REF is the desired reference frame for the returned */
296 /* pointing. The returned C-matrix CMAT gives the */
297 /* orientation of the instrument designated by INST */
298 /* relative to the frame designated by REF. When a */
299 /* vector specified relative to frame REF is left- */
300 /* multiplied by CMAT, the vector is rotated to the */
301 /* frame associated with INST. See the discussion of */
302 /* CMAT below for details. */
303
304 /* Consult the SPICE document "Frames" for a discussion */
305 /* of supported reference frames. */
306
307 /* $ Detailed_Output */
308
309 /* CMAT is a rotation matrix that transforms the components of */
310 /* a vector expressed in the reference frame specified by */
311 /* REF to components expressed in the frame tied to the */
312 /* instrument, spacecraft, or other structure at time */
313 /* CLKOUT (see below). */
314
315 /* Thus, if a vector v has components x,y,z in the REF */
316 /* reference frame, then v has components x',y',z' in the */
317 /* instrument fixed frame at time CLKOUT: */
318
319 /* [ x' ] [ ] [ x ] */
320 /* | y' | = | CMAT | | y | */
321 /* [ z' ] [ ] [ z ] */
322
323 /* If you know x', y', z', use the transpose of the */
324 /* C-matrix to determine x, y, z as follows: */
325
326 /* [ x ] [ ]T [ x' ] */
327 /* | y | = | CMAT | | y' | */
328 /* [ z ] [ ] [ z' ] */
329 /* (Transpose of CMAT) */
330
331
332 /* CLKOUT is the encoded spacecraft clock time associated with */
333 /* the returned C-matrix. This value may differ from the */
334 /* requested time, but never by more than the input */
335 /* tolerance TOL. */
336
337 /* The particulars section below describes the search */
338 /* algorithm used by CKGP to satisfy a pointing */
339 /* request. This algorithm determines the pointing */
340 /* instance (and therefore the associated time value) */
341 /* that is returned. */
342
343 /* FOUND is true if a record was found to satisfy the pointing */
344 /* request. FOUND will be false otherwise. */
345
346 /* $ Parameters */
347
348 /* None. */
349
350 /* $ Exceptions */
351
352 /* 1) If a C-kernel file has not been loaded using FURNSH prior to */
353 /* a call to this routine, an error is signaled by a routine in */
354 /* the call tree of this routine. */
355
356 /* 2) If TOL is negative, found is set to .FALSE. */
357
358 /* 3) If REF is not a supported reference frame, an error is */
359 /* signaled by a routine in the call tree of this routine and */
360 /* FOUND is set to .FALSE. */
361
362 /* $ Files */
363
364 /* CKGP searches through files loaded by FURNSH to locate a */
365 /* segment that can satisfy the request for pointing for instrument */
366 /* INST at time SCLKDP. You must load a C-kernel file using FURNSH */
367 /* prior to calling this routine. */
368
369 /* $ Particulars */
370
371 /* How the tolerance argument is used */
372 /* ================================== */
373
374
375 /* Reading a type 1 CK segment (discrete pointing instances) */
376 /* --------------------------------------------------------- */
377
378 /* In the diagram below */
379
380 /* - "0" is used to represent discrete pointing instances */
381 /* (quaternions and associated time tags). */
382
383 /* - "( )" are used to represent the end points of the time */
384 /* interval covered by a segment in a CK file. */
385
386 /* - SCLKDP is the time at which you requested pointing. */
387 /* The location of SCLKDP relative to the time tags of the */
388 /* pointing instances is indicated by the "+" sign. */
389
390 /* - TOL is the time tolerance specified in the pointing */
391 /* request. The square brackets "[ ]" represent the */
392 /* endpoints of the time interval */
393
394 /* SCLKDP-TOL : SCLKDP+TOL */
395
396 /* - The quaternions occurring in the segment need not be */
397 /* evenly spaced in time. */
398
399
400 /* Case 1: pointing is available */
401 /* ------------------------------ */
402
403 /* SCLKDP */
404 /* \ TOL */
405 /* | / */
406 /* |/\ */
407 /* Your request [--+--] */
408 /* . . . */
409 /* Segment (0-----0--0--0--0--0--0---0--0------------0--0--0--0) */
410 /* ^ */
411 /* | */
412 /* CKGP returns this instance. */
413
414
415 /* Case 2: pointing is not available */
416 /* ---------------------------------- */
417
418 /* SCLKDP */
419 /* \ TOL */
420 /* | / */
421 /* |/\ */
422 /* Your request [--+--] */
423 /* . . . */
424 /* Segment (0-----0--0--0--0--0--0---0--0--0---------0--0--0--0) */
425
426
427 /* CKGP returns no pointing; the output */
428 /* FOUND flag is set to .FALSE. */
429
430
431
432 /* Reading a type 2, 3, 4, or 5 CK segment (continuous pointing) */
433 /* ------------------------------------------------------------- */
434
435 /* In the diagrams below */
436
437 /* - "==" is used to represent periods of continuous pointing. */
438
439 /* - "--" is used to represent gaps in the pointing coverage. */
440
441 /* - "( )" are used to represent the end points of the time */
442 /* interval covered by a segment in a CK file. */
443
444 /* - SCLKDP is the time at which you requested pointing. */
445 /* The location of SCLKDP relative to the time tags of the */
446 /* pointing instances is indicated by the "+" sign. */
447
448 /* - TOL is the time tolerance specified in the pointing */
449 /* request. The square brackets "[ ]" represent the */
450 /* endpoints of the time interval */
451
452 /* SCLKDP-TOL : SCLKDP+TOL */
453
454 /* - The quaternions occurring in the periods of continuous */
455 /* pointing need not be evenly spaced in time. */
456
457
458 /* Case 1: pointing is available at the request time */
459 /* -------------------------------------------------- */
460
461 /* SCLKDP */
462 /* \ TOL */
463 /* | / */
464 /* |/\ */
465 /* Your request [--+--] */
466 /* . . . */
467 /* . . . */
468 /* . . . */
469 /* Segment (==---===========---=======----------===--) */
470 /* ^ */
471 /* | */
472
473 /* The request time lies within an interval where */
474 /* continuous pointing is available. CKGP returns */
475 /* pointing at the requested epoch. */
476
477
478 /* Case 2: pointing is available "near" the request time */
479 /* ------------------------------------------------------ */
480
481 /* SCLKDP */
482 /* \ TOL */
483 /* | / */
484 /* |/\ */
485 /* Your request [--+--] */
486 /* . . . */
487 /* Segment (==---===========----=======---------===--) */
488 /* ^ */
489 /* | */
490
491 /* The request time lies in a gap: an interval where */
492 /* continuous pointing is *not* available. CKGP */
493 /* returns pointing for the epoch closest to the */
494 /* request time SCLKDP. */
495
496
497 /* Case 3: pointing is not available */
498 /* ---------------------------------- */
499
500 /* SCLKDP */
501 /* \ TOL */
502 /* | / */
503 /* |/\ */
504 /* Your request [--+--] */
505 /* . . . */
506 /* Segment (==---===========----=======---------===--) */
507
508 /* CKGP returns no pointing; the output */
509 /* FOUND flag is set to .FALSE. */
510
511
512
513 /* Tolerance and segment priority */
514 /* ============================== */
515
516 /* CKGP searches through loaded C-kernels to satisfy a pointing */
517 /* request. Last-loaded files are searched first. Individual files */
518 /* are searched in backwards order, so that between competing */
519 /* segments (segments containing data for the same object, for */
520 /* overlapping time ranges), the one closest to the end of the file */
521 /* has highest priority. */
522
523 /* The search ends when a segment is found that can provide pointing */
524 /* for the specified instrument at a time falling within the */
525 /* specified tolerance on either side of the request time. Within */
526 /* that segment, the instance closest to the input time is located */
527 /* and returned. */
528
529 /* The following four cases illustrate this search procedure. */
530 /* Segments A and B are in the same file, with segment A located */
531 /* further towards the end of the file than segment B. Both segments */
532 /* A and B contain discrete pointing data, indicated by the number */
533 /* 0. */
534
535
536 /* Case 1: Pointing is available in the first segment searched. */
537 /* Because segment A has the highest priority and can */
538 /* satisfy the request, segment B is not searched. */
539
540
541 /* SCLKDP */
542 /* \ TOL */
543 /* | / */
544 /* |/\ */
545 /* Your request [--+--] */
546 /* . . . */
547 /* Segment A (0-----------------0--------0--0-----0) */
548 /* ^ */
549 /* | */
550 /* | */
551 /* CKGP returns this instance */
552
553 /* Segment B (0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0) */
554
555
556
557 /* Case 2: Pointing is not available in the first segment searched. */
558 /* Because segment A cannot satisfy the request, segment B */
559 /* is searched. */
560
561
562 /* SCLKDP */
563 /* \ TOL */
564 /* | / */
565 /* |/\ */
566 /* Your request [--+--] */
567 /* . . . */
568 /* Segment A (0-----------------0--------0--0-----0) */
569 /* . . . */
570 /* Segment B (0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0--0) */
571 /* ^ */
572 /* | */
573 /* CKGP returns this instance */
574
575
576 /* Segments that contain continuous pointing data are searched in */
577 /* the same manner as segments containing discrete pointing data. */
578 /* For request times that fall within the bounds of continuous */
579 /* intervals, CKGP will return pointing at the request time. When */
580 /* the request time does not fall within an interval, then a time at */
581 /* an endpoint of an interval may be returned if it is the closest */
582 /* time in the segment to the user request time and is also within */
583 /* the tolerance. */
584
585 /* In the following examples, segment A is located further towards */
586 /* the end of the file than segment C. Segment A contains discrete */
587 /* pointing data and segment C contains continuous data, indicated */
588 /* by the "=" character. */
589
590
591 /* Case 3: Pointing is not available in the first segment searched. */
592 /* Because segment A cannot satisfy the request, segment C */
593 /* is searched. */
594
595 /* SCLKDP */
596 /* \ TOL */
597 /* | / */
598 /* |/\ */
599 /* Your request [--+--] */
600 /* . . . */
601 /* . . . */
602 /* Segment A (0-----------------0--------0--0-----0) */
603 /* . . . */
604 /* . . . */
605 /* Segment C (---=============-----====--------==--) */
606 /* ^ */
607 /* | */
608 /* | */
609 /* CKGP returns this instance */
610
611
612 /* In the next case, assume that the order of segments A and C in the */
613 /* file is reversed: A is now closer to the front, so data from */
614 /* segment C are considered first. */
615
616
617 /* Case 4: Pointing is available in the first segment searched. */
618 /* Because segment C has the highest priority and can */
619 /* satisfy the request, segment A is not searched. */
620
621 /* SCLKDP */
622 /* / */
623 /* | TOL */
624 /* | / */
625 /* |/\ */
626 /* Your request [--+--] */
627 /* . . . */
628 /* . . . */
629 /* Segment C (---=============-----====--------==--) */
630 /* ^ */
631 /* | */
632 /* CKGP returns this instance */
633
634 /* Segment A (0-----------------0--------0--0-----0) */
635 /* ^ */
636 /* | */
637 /* "Best" answer */
638
639
640 /* The next case illustrates an unfortunate side effect of using */
641 /* a non-zero tolerance when reading multi-segment CKs with */
642 /* continuous data. In all cases when the look-up interval */
643 /* formed using tolerance overlaps a segment boundary and */
644 /* the request time falls within the coverage of the lower */
645 /* priority segment, the data at the end of the higher priority */
646 /* segment will be picked instead of the data from the lower */
647 /* priority segment. */
648
649
650 /* Case 5: Pointing is available in the first segment searched. */
651 /* Because segment C has the highest priority and can */
652 /* satisfy the request, segment A is not searched. */
653
654 /* SCLKDP */
655 /* / */
656 /* | TOL */
657 /* | / */
658 /* |/\ */
659 /* Your request [--+--] */
660 /* . . . */
661 /* . . . */
662 /* Segment C (===============) */
663 /* ^ */
664 /* | */
665 /* CKGP returns this instance */
666
667 /* Segment A (=====================) */
668 /* ^ */
669 /* | */
670 /* "Best" answer */
671
672 /* $ Examples */
673
674 /* Suppose you have two C-kernel files containing data for the */
675 /* Voyager 2 narrow angle camera. One file contains predict values, */
676 /* and the other contains corrected pointing for a selected group */
677 /* of images, that is, for a subset of images from the first file. */
678
679 /* The following example program uses CKGP to get C-matrices for a */
680 /* set of images whose SCLK counts (un-encoded character string */
681 /* versions) are contained in the array SCLKCH. */
682
683 /* If available, the program will get the corrected pointing values. */
684 /* Otherwise, predict values will be used. */
685
686 /* For each C-matrix, a unit pointing vector is constructed */
687 /* and printed. */
688
689
690 /* C */
691 /* C Constants for this program. */
692 /* C */
693 /* C -- The code for the Voyager 2 spacecraft clock is -32 */
694 /* C */
695 /* C -- The code for the narrow angle camera on the Voyager 2 */
696 /* C spacecraft is -32001. */
697 /* C */
698 /* C -- Spacecraft clock times for successive Voyager images */
699 /* C always differ by more than 0:0:400. This is an */
700 /* C acceptable tolerance, and must be converted to "ticks" */
701 /* C (units of encoded SCLK) for input to CKGP. */
702 /* C */
703 /* C -- The reference frame we want is FK4. */
704 /* C */
705 /* C -- The narrow angle camera boresight defines the third */
706 /* C axis of the instrument-fixed coordinate system. */
707 /* C Therefore, the vector ( 0, 0, 1 ) represents */
708 /* C the boresight direction in the camera-fixed frame. */
709 /* C */
710 /* IMPLICIT NONE */
711
712 /* INTEGER FILEN */
713 /* PARAMETER ( FILEN = 255 ) */
714
715 /* INTEGER NPICS */
716 /* PARAMETER ( NPICS = 2 ) */
717
718 /* INTEGER TIMLEN */
719 /* PARAMETER ( TIMLEN = 30 ) */
720
721 /* INTEGER REFLEN */
722 /* PARAMETER ( REFLEN = 32 ) */
723
724 /* CHARACTER*(TIMLEN) CLKCH */
725 /* CHARACTER*(FILEN) CKPRED */
726 /* CHARACTER*(FILEN) CKCORR */
727 /* CHARACTER*(REFLEN) REF */
728 /* CHARACTER*(FILEN) SCLK */
729 /* CHARACTER*(TIMLEN) SCLKCH ( NPICS ) */
730 /* CHARACTER*(TIMLEN) TOLVGR */
731
732 /* DOUBLE PRECISION CLKOUT */
733 /* DOUBLE PRECISION CMAT ( 3, 3 ) */
734 /* DOUBLE PRECISION SCLKDP */
735 /* DOUBLE PRECISION TOLTIK */
736 /* DOUBLE PRECISION VCFIX ( 3 ) */
737 /* DOUBLE PRECISION VINERT ( 3 ) */
738
739 /* INTEGER SC */
740 /* INTEGER I */
741 /* INTEGER INST */
742
743 /* LOGICAL FOUND */
744
745 /* CKPRED = 'voyager2_predict.bc' */
746 /* CKCORR = 'voyager2_corrected.bc' */
747 /* SCLK = 'voyager2_sclk.tsc' */
748 /* SC = -32 */
749 /* INST = -32001 */
750 /* SCLKCH(1) = '4/08966:30:768' */
751 /* SCLKCH(2) = '4/08970:58:768' */
752 /* TOLVGR = '0:0:400' */
753 /* REF = 'FK4' */
754 /* VCFIX( 1 ) = 0.D0 */
755 /* VCFIX( 2 ) = 0.D0 */
756 /* VCFIX( 3 ) = 1.D0 */
757
758 /* C */
759 /* C Loading the files in this order ensures that the */
760 /* C corrected file will get searched first. */
761 /* C */
762 /* CALL FURNSH ( CKPRED ) */
763 /* CALL FURNSH ( CKCORR ) */
764
765 /* C */
766 /* C Need to load a Voyager 2 SCLK kernel to convert from */
767 /* C clock strings to ticks. */
768 /* C */
769 /* CALL FURNSH ( SCLK ) */
770
771 /* C */
772 /* C Convert tolerance from VGR formatted character string */
773 /* C SCLK to ticks which are units of encoded SCLK. */
774 /* C */
775 /* CALL SCTIKS ( SC, TOLVGR, TOLTIK ) */
776
777
778 /* DO I = 1, NPICS */
779 /* C */
780 /* C CKGP requires encoded spacecraft clock. */
781 /* C */
782 /* CALL SCENCD ( SC, SCLKCH( I ), SCLKDP ) */
783
784 /* CALL CKGP ( INST, SCLKDP, TOLTIK, REF, CMAT, */
785 /* . CLKOUT, FOUND ) */
786
787 /* IF ( FOUND ) THEN */
788
789 /* C */
790 /* C Use the transpose of the C-matrix to transform the */
791 /* C boresight vector from camera-fixed to reference */
792 /* C coordinates. */
793 /* C */
794 /* CALL MTXV ( CMAT, VCFIX, VINERT ) */
795 /* CALL SCDECD ( SC, CLKOUT, CLKCH ) */
796
797 /* WRITE (*,*) 'VGR 2 SCLK Time: ', CLKCH */
798 /* WRITE (*,*) 'VGR 2 NA ISS boresight ' */
799 /* . // 'pointing vector: ', VINERT */
800
801 /* ELSE */
802
803 /* WRITE (*,*) 'Pointing not found for time ', SCLKCH(I) */
804
805 /* END IF */
806
807 /* END DO */
808
809 /* END */
810
811
812 /* $ Restrictions */
813
814 /* None. */
815
816 /* $ Literature_References */
817
818 /* None. */
819
820 /* $ Author_and_Institution */
821
822 /* C.H. Acton (JPL) */
823 /* N.J. Bachman (JPL) */
824 /* W.L. Taber (JPL) */
825 /* J.M. Lynch (JPL) */
826 /* B.V. Semenov (JPL) */
827 /* M.J. Spencer (JPL) */
828 /* R.E. Thurman (JPL) */
829 /* I.M. Underwood (JPL) */
830
831 /* $ Version */
832
833 /* - SPICELIB Version 5.4.0, 23-SEP-2013 (BVS) */
834
835 /* Updated to save the input frame name and POOL state counter */
836 /* and to do frame name-ID conversion only if the counter has */
837 /* changed. */
838
839 /* - SPICELIB Version 5.3.1, 09-JUN-2010 (BVS) */
840
841 /* Header update: description of the tolerance and Particulars */
842 /* section were expanded to address some problems arising from */
843 /* using a non-zero tolerance. */
844
845 /* - SPICELIB Version 5.3.0, 23-APR-2010 (NJB) */
846
847 /* Bug fix: this routine now obtains the rotation */
848 /* from the request frame to the applicable CK segment's */
849 /* base frame via a call to REFCHG. Formerly the routine */
850 /* used FRMCHG, which required that angular velocity data */
851 /* be available for this transformation. */
852
853 /* - SPICELIB Version 5.2.0, 25-AUG-2005 (NJB) */
854
855 /* Updated to remove non-standard use of duplicate arguments */
856 /* in MXM call. */
857
858 /* - SPICELIB Version 5.1.2, 29-JAN-2004 (NJB) */
859
860 /* Header update: description of input argument REF was */
861 /* expanded. */
862
863 /* - SPICELIB Version 5.1.1, 27-JUL-2003 (CHA) (NJB) */
864
865 /* Various header corrections were made. */
866
867 /* - SPICELIB Version 3.2.0, 23-FEB-1999 (WLT) */
868
869 /* The previous editions of this routine did not properly handle */
870 /* the case when TOL was negative. The routine now returns a */
871 /* value of .FALSE. for FOUND as is advertised above. */
872
873 /* - SPICELIB Version 3.1.0, 13-APR-1998 (WLT) */
874
875 /* The call to CHKOUT in the case when FAILED returned the */
876 /* value TRUE used to check out with the name 'CKGPAV'. This */
877 /* has been changed to a CKGP. */
878
879 /* - SPICELIB Version 3.0.0, 19-SEP-1994 (WLT) */
880
881 /* The routine was upgraded to support non-inertial frames. */
882
883 /* - SPICELIB Version 2.0.1, 10-MAR-1992 (WLT) */
884
885 /* Comment section for permuted index source lines was added */
886 /* following the header. */
887
888 /* - SPICELIB Version 2.0.0, 30-AUG-1991 (JML) */
889
890 /* The Particulars section was updated to show how the */
891 /* search algorithm processes segments with continuous */
892 /* pointing data. */
893
894 /* The example program now loads an SCLK kernel. */
895
896 /* FAILED is checked after the call to IRFROT to handle the */
897 /* case where the reference frame is invalid and the error */
898 /* handling is not set to abort. */
899
900 /* FAILED is checked in the DO WHILE loop to handle the case */
901 /* where an error is detected by a SPICELIB routine inside the */
902 /* loop and the error handling is not set to abort. */
903
904 /* - SPICELIB Version 1.0.1, 02-NOV-1990 (JML) */
905
906 /* The restriction that a C-kernel file must be loaded */
907 /* was explicitly stated. */
908
909
910 /* - SPICELIB Version 1.0.0, 07-SEP-1990 (RET) (IMU) */
911
912 /* -& */
913 /* $ Index_Entries */
914
915 /* get ck pointing */
916
917 /* -& */
918 /* $ Revisions */
919
920 /* - SPICELIB Version 5.2.0, 25-AUG-2005 (NJB) */
921
922 /* Updated to remove non-standard use of duplicate arguments */
923 /* in MXM call. */
924
925 /* - SPICELIB Version 3.1.0, 20-DEC-1995 (WLT) */
926
927 /* A call to FRINFO did not have enough arguments and */
928 /* went undetected until Howard Taylor of ACT. Many */
929 /* thanks go out to Howard for tracking down this error. */
930
931 /* - SPICELIB Version 3.0.0, 19-SEP-1994 (WLT) */
932
933 /* The routine was upgraded to support non-inertial frames. */
934
935 /* Calls to NAMIRF and IRFROT were replaced with calls to */
936 /* NAMFRM and FRMCHG respectively. */
937
938
939 /* - SPICELIB Version 1.0.2, 30-AUG-1991 (JML) */
940
941 /* 1) The Particulars section was updated to show how the */
942 /* search algorithm processes segments with continuous */
943 /* pointing data. */
944
945 /* 2) The example program now loads an SCLK kernel. */
946
947 /* 3) FAILED is checked after the call to IRFROT to handle the */
948 /* case where the reference frame is invalid and the error */
949 /* handling is not set to abort. */
950
951 /* 4) FAILED is checked in the DO WHILE loop to handle the case */
952 /* where an error is detected by a SPICELIB routine inside the */
953 /* loop and the error handling is not set to abort. */
954
955 /* - SPICELIB Version 1.0.1, 02-NOV-1990 (JML) */
956
957 /* 1) The restriction that a C-kernel file must be loaded */
958 /* was explicitly stated. */
959 /* 2) Minor changes were made to the wording of the header. */
960
961
962 /* - Beta Version 1.1.0, 29-AUG-1990 (MJS) */
963
964 /* The following changes were made as a result of the */
965 /* NAIF CK Code and Documentation Review: */
966
967 /* 1) The variable SCLK was changed to SCLKDP. */
968 /* 2) The variable INSTR was changed to INST. */
969 /* 3) The variable IDENT was changed to SEGID. */
970 /* 4) The declarations for the parameters NDC, NIC, NC, and */
971 /* IDLEN were moved from the "Declarations" section of the */
972 /* header to the "Local parameters" section of the code below */
973 /* the header. These parameters are not meant to modified by */
974 /* users. */
975 /* 5) The header was updated to reflect the changes. */
976
977 /* - Beta Version 1.0.0, 04-MAY-1990 (RET) (IMU) */
978
979 /* -& */
980
981 /* SPICELIB functions */
982
983
984 /* Local parameters */
985
986 /* NDC is the number of double precision components in an */
987 /* unpacked C-kernel segment descriptor. */
988
989 /* NIC is the number of integer components in an unpacked */
990 /* C-kernel segment descriptor. */
991
992 /* NC is the number of components in a packed C-kernel */
993 /* descriptor. All DAF summaries have this formulaic */
994 /* relationship between the number of its integer and */
995 /* double precision components and the number of packed */
996 /* components. */
997
998 /* IDLEN is the length of the C-kernel segment identifier. */
999 /* All DAF names have this formulaic relationship */
1000 /* between the number of summary components and */
1001 /* the length of the name (You will notice that */
1002 /* a name and a summary have the same length in bytes.) */
1003
1004
1005 /* Saved frame name length. */
1006
1007
1008 /* Local variables */
1009
1010
1011 /* Saved frame name/ID item declarations. */
1012
1013
1014 /* Saved frame name/ID items. */
1015
1016
1017 /* Initial values. */
1018
1019
1020 /* Standard SPICE error handling. */
1021
1022 if (return_()) {
1023 return 0;
1024 } else {
1025 chkin_("CKGP", (ftnlen)4);
1026 }
1027
1028 /* Initialization. */
1029
1030 if (first) {
1031
1032 /* Initialize counter. */
1033
1034 zzctruin_(svctr1);
1035 first = FALSE_;
1036 }
1037
1038 /* Don't need angular velocity data. */
1039 /* Assume the segment won't be found until it really is. */
1040
1041 needav = FALSE_;
1042 *found = FALSE_;
1043
1044 /* If the tolerance is less than zero, we go no further. */
1045
1046 if (*tol < 0.) {
1047 chkout_("CKGP", (ftnlen)4);
1048 return 0;
1049 }
1050
1051 /* Begin a search for this instrument and time, and get the first */
1052 /* applicable segment. */
1053
1054 ckbss_(inst, sclkdp, tol, &needav);
1055 cksns_(&handle, descr, segid, &sfnd, (ftnlen)40);
1056
1057 /* Keep trying candidate segments until a segment can produce a */
1058 /* pointing instance within the specified time tolerance of the */
1059 /* input time. */
1060
1061 /* Check FAILED to prevent an infinite loop if an error is detected */
1062 /* by a SPICELIB routine and the error handling is not set to abort. */
1063
1064 while(sfnd && ! failed_()) {
1065 ckpfs_(&handle, descr, sclkdp, tol, &needav, cmat, av, clkout, &pfnd);
1066 if (pfnd) {
1067
1068 /* Found one. If the C-matrix doesn't already rotate from the */
1069 /* requested frame, convert it to one that does. */
1070
1071 dafus_(descr, &c__2, &c__6, dcd, icd);
1072 refseg = icd[1];
1073
1074 /* Look up the id code for the requested reference frame. */
1075
1076 zznamfrm_(svctr1, svref, &svrefr, ref, &refreq, (ftnlen)32,
1077 ref_len);
1078 if (refreq != refseg) {
1079
1080 /* We may need to convert the output ticks CLKOUT to ET */
1081 /* so that we can get the needed state transformation */
1082 /* matrix. This is the case if either of the frames */
1083 /* is non-inertial. */
1084
1085 frinfo_(&refreq, ¢er, &type1, &typeid, &gotit);
1086 frinfo_(&refseg, ¢er, &type2, &typeid, &gotit);
1087 if (type1 == 1 && type2 == 1) {
1088
1089 /* Any old value of ET will do in this case. We'll */
1090 /* use zero. */
1091
1092 et = 0.;
1093 } else {
1094
1095 /* Look up the spacecraft clock id to use to convert */
1096 /* the output CLKOUT to ET. */
1097
1098 ckmeta_(inst, "SCLK", &sclk, (ftnlen)4);
1099 sct2e_(&sclk, clkout, &et);
1100 }
1101
1102 /* Get the transformation from the requested frame to */
1103 /* the segment frame at ET. */
1104
1105 refchg_(&refreq, &refseg, &et, rot);
1106
1107 /* If REFCHG detects that the reference frame is invalid */
1108 /* then return from this routine with FOUND equal to false. */
1109
1110 if (failed_()) {
1111 chkout_("CKGP", (ftnlen)4);
1112 return 0;
1113 }
1114
1115 /* Transform the attitude information: convert CMAT so that */
1116 /* it maps from request frame to C-matrix frame. */
1117
1118 mxm_(cmat, rot, tmpmat);
1119 moved_(tmpmat, &c__9, cmat);
1120 }
1121 *found = TRUE_;
1122 chkout_("CKGP", (ftnlen)4);
1123 return 0;
1124 }
1125 cksns_(&handle, descr, segid, &sfnd, (ftnlen)40);
1126 }
1127 chkout_("CKGP", (ftnlen)4);
1128 return 0;
1129 } /* ckgp_ */
1130
1131