-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathpreceph.c
750 lines (670 loc) · 26.1 KB
/
preceph.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
/*------------------------------------------------------------------------------
* preceph.c : precise ephemeris and clock functions
*
* Copyright (C) 2007-2017 by T.TAKASU, All rights reserved.
*
* references :
* [1] S.Hilla, The Extended Standard Product 3 Orbit Format (SP3-c),
* 12 February, 2007
* [2] J.Ray, W.Gurtner, RINEX Extensions to Handle Clock Information,
* 27 August, 1998
* [3] D.D.McCarthy, IERS Technical Note 21, IERS Conventions 1996, July 1996
* [4] D.A.Vallado, Fundamentals of Astrodynamics and Applications 2nd ed,
* Space Technology Library, 2004
*
* version : $Revision: 1.1 $ $Date: 2008/07/17 21:48:06 $
* history : 2009/01/18 1.0 new
* 2009/01/31 1.1 fix bug on numerical error to read sp3a ephemeris
* 2009/05/15 1.2 support glonass,galileo,qzs
* 2009/12/11 1.3 support wild-card expansion of file path
* 2010/07/21 1.4 added api:
* eci2ecef(),sunmoonpos(),peph2pos(),satantoff(),
* readdcb()
* changed api:
* readsp3()
* deleted api:
* eph2posp()
* 2010/09/09 1.5 fix problem when precise clock outage
* 2011/01/23 1.6 support qzss satellite code
* 2011/09/12 1.7 fix problem on precise clock outage
* move sunmmonpos() to rtkcmn.c
* 2011/12/01 1.8 modify api readsp3()
* precede later ephemeris if ephemeris is NULL
* move eci2ecef() to rtkcmn.c
* 2013/05/08 1.9 fix bug on computing std-dev of precise clocks
* 2013/11/20 1.10 modify option for api readsp3()
* 2014/04/03 1.11 accept extenstion including sp3,eph,SP3,EPH
* 2014/05/23 1.12 add function to read sp3 velocity records
* change api: satantoff()
* 2014/08/31 1.13 add member cov and vco in peph_t sturct
* 2014/10/13 1.14 fix bug on clock error variance in peph2pos()
* 2015/05/10 1.15 add api readfcb()
* modify api readdcb()
* 2017/04/11 1.16 fix bug on antenna offset correction in peph2pos()
*-----------------------------------------------------------------------------*/
#include "rtklib.h"
#define SQR(x) ((x)*(x))
#define NMAX 10 /* order of polynomial interpolation */
#define MAXDTE 900.0 /* max time difference to ephem time (s) */
#define EXTERR_CLK 1E-3 /* extrapolation error for clock (m/s) */
#define EXTERR_EPH 5E-7 /* extrapolation error for ephem (m/s^2) */
/* satellite code to satellite system ----------------------------------------*/
static int code2sys(char code)
{
if (code=='G'||code==' ') return SYS_GPS;
if (code=='R') return SYS_GLO;
if (code=='E') return SYS_GAL; /* extension to sp3-c */
if (code=='J') return SYS_QZS; /* extension to sp3-c */
if (code=='C') return SYS_CMP; /* extension to sp3-c */
if (code=='L') return SYS_LEO; /* extension to sp3-c */
return SYS_NONE;
}
/* read sp3 header -----------------------------------------------------------*/
static int readsp3h(FILE *fp, gtime_t *time, char *type, int *sats,
double *bfact, char *tsys)
{
int i,j,k=0,ns=0,sys,prn;
char buff[1024];
trace(3,"readsp3h:\n");
for (i=0;i<22;i++) {
if (!fgets(buff,sizeof(buff),fp)) break;
if (i==0) {
*type=buff[2];
if (str2time(buff,3,28,time)) return 0;
}
else if (2<=i&&i<=6) {
if (i==2) {
ns=(int)str2num(buff,4,2);
}
for (j=0;j<17&&k<ns;j++) {
sys=code2sys(buff[9+3*j]);
prn=(int)str2num(buff,10+3*j,2);
if (k<MAXSAT) sats[k++]=satno(sys,prn);
}
}
else if (i==12) {
strncpy(tsys,buff+9,3); tsys[3]='\0';
}
else if (i==14) {
bfact[0]=str2num(buff, 3,10);
bfact[1]=str2num(buff,14,12);
}
}
return ns;
}
/* add precise ephemeris -----------------------------------------------------*/
static int addpeph(nav_t *nav, peph_t *peph)
{
peph_t *nav_peph;
if (nav->ne>=nav->nemax) {
nav->nemax+=256;
if (!(nav_peph=(peph_t *)realloc(nav->peph,sizeof(peph_t)*nav->nemax))) {
trace(1,"readsp3b malloc error n=%d\n",nav->nemax);
free(nav->peph); nav->peph=NULL; nav->ne=nav->nemax=0;
return 0;
}
nav->peph=nav_peph;
}
nav->peph[nav->ne++]=*peph;
return 1;
}
/* read sp3 body -------------------------------------------------------------*/
static void readsp3b(FILE *fp, char type, int *sats, int ns, double *bfact,
char *tsys, int index, int opt, nav_t *nav)
{
peph_t peph;
gtime_t time;
double val,std,base;
int i,j,sat,sys,prn,n=ns*(type=='P'?1:2),pred_o,pred_c,v;
char buff[1024];
trace(3,"readsp3b: type=%c ns=%d index=%d opt=%d\n",type,ns,index,opt);
while (fgets(buff,sizeof(buff),fp)) {
if (!strncmp(buff,"EOF",3)) break;
if (buff[0]!='*'||str2time(buff,3,28,&time)) {
trace(2,"sp3 invalid epoch %31.31s\n",buff);
continue;
}
if (!strcmp(tsys,"UTC")) time=utc2gpst(time); /* utc->gpst */
peph.time =time;
peph.index=index;
for (i=0;i<MAXSAT;i++) {
for (j=0;j<4;j++) {
peph.pos[i][j]=0.0;
peph.std[i][j]=0.0f;
peph.vel[i][j]=0.0;
peph.vst[i][j]=0.0f;
}
for (j=0;j<3;j++) {
peph.cov[i][j]=0.0f;
peph.vco[i][j]=0.0f;
}
}
for (i=pred_o=pred_c=v=0;i<n&&fgets(buff,sizeof(buff),fp);i++) {
if (strlen(buff)<4||(buff[0]!='P'&&buff[0]!='V')) continue;
sys=buff[1]==' '?SYS_GPS:code2sys(buff[1]);
prn=(int)str2num(buff,2,2);
if (sys==SYS_SBS) prn+=100;
else if (sys==SYS_QZS) prn+=192; /* extension to sp3-c */
if (!(sat=satno(sys,prn))) continue;
if (buff[0]=='P') {
pred_c=strlen(buff)>=76&&buff[75]=='P';
pred_o=strlen(buff)>=80&&buff[79]=='P';
}
for (j=0;j<4;j++) {
/* read option for predicted value */
if (j< 3&&(opt&1)&& pred_o) continue;
if (j< 3&&(opt&2)&&!pred_o) continue;
if (j==3&&(opt&1)&& pred_c) continue;
if (j==3&&(opt&2)&&!pred_c) continue;
val=str2num(buff, 4+j*14,14);
std=str2num(buff,61+j* 3,j<3?2:3);
if (buff[0]=='P') { /* position */
if (val!=0.0&&fabs(val-999999.999999)>=1E-6) {
peph.pos[sat-1][j]=val*(j<3?1000.0:1E-6);
v=1; /* valid epoch */
}
if ((base=bfact[j<3?0:1])>0.0&&std>0.0) {
peph.std[sat-1][j]=(float)(pow(base,std)*(j<3?1E-3:1E-12));
}
}
else if (v) { /* velocity */
if (val!=0.0&&fabs(val-999999.999999)>=1E-6) {
peph.vel[sat-1][j]=val*(j<3?0.1:1E-10);
}
if ((base=bfact[j<3?0:1])>0.0&&std>0.0) {
peph.vst[sat-1][j]=(float)(pow(base,std)*(j<3?1E-7:1E-16));
}
}
}
}
if (v) {
if (!addpeph(nav,&peph)) return;
}
}
}
/* compare precise ephemeris -------------------------------------------------*/
static int cmppeph(const void *p1, const void *p2)
{
peph_t *q1=(peph_t *)p1,*q2=(peph_t *)p2;
double tt=timediff(q1->time,q2->time);
return tt<-1E-9?-1:(tt>1E-9?1:q1->index-q2->index);
}
/* combine precise ephemeris -------------------------------------------------*/
static void combpeph(nav_t *nav, int opt)
{
int i,j,k,m;
trace(3,"combpeph: ne=%d\n",nav->ne);
qsort(nav->peph,nav->ne,sizeof(peph_t),cmppeph);
if (opt&4) return;
for (i=0,j=1;j<nav->ne;j++) {
if (fabs(timediff(nav->peph[i].time,nav->peph[j].time))<1E-9) {
for (k=0;k<MAXSAT;k++) {
if (norm(nav->peph[j].pos[k],4)<=0.0) continue;
for (m=0;m<4;m++) nav->peph[i].pos[k][m]=nav->peph[j].pos[k][m];
for (m=0;m<4;m++) nav->peph[i].std[k][m]=nav->peph[j].std[k][m];
for (m=0;m<4;m++) nav->peph[i].vel[k][m]=nav->peph[j].vel[k][m];
for (m=0;m<4;m++) nav->peph[i].vst[k][m]=nav->peph[j].vst[k][m];
}
}
else if (++i<j) nav->peph[i]=nav->peph[j];
}
nav->ne=i+1;
trace(4,"combpeph: ne=%d\n",nav->ne);
}
/* read sp3 precise ephemeris file ---------------------------------------------
* read sp3 precise ephemeris/clock files and set them to navigation data
* args : char *file I sp3-c precise ephemeris file
* (wind-card * is expanded)
* nav_t *nav IO navigation data
* int opt I options (1: only observed + 2: only predicted +
* 4: not combined)
* return : none
* notes : see ref [1]
* precise ephemeris is appended and combined
* nav->peph and nav->ne must by properly initialized before calling the
* function
* only files with extensions of .sp3, .SP3, .eph* and .EPH* are read
*-----------------------------------------------------------------------------*/
extern void readsp3(const char *file, nav_t *nav, int opt)
{
FILE *fp;
gtime_t time={0};
double bfact[2]={0};
int i,j,n,ns,sats[MAXSAT]={0};
char *efiles[MAXEXFILE],*ext,type=' ',tsys[4]="";
trace(3,"readpephs: file=%s\n",file);
for (i=0;i<MAXEXFILE;i++) {
if (!(efiles[i]=(char *)malloc(1024))) {
for (i--;i>=0;i--) free(efiles[i]);
return;
}
}
/* expand wild card in file path */
n=expath(file,efiles,MAXEXFILE);
for (i=j=0;i<n;i++) {
if (!(ext=strrchr(efiles[i],'.'))) continue;
if (!strstr(ext+1,"sp3")&&!strstr(ext+1,".SP3")&&
!strstr(ext+1,"eph")&&!strstr(ext+1,".EPH")) continue;
if (!(fp=fopen(efiles[i],"r"))) {
trace(2,"sp3 file open error %s\n",efiles[i]);
continue;
}
/* read sp3 header */
ns=readsp3h(fp,&time,&type,sats,bfact,tsys);
/* read sp3 body */
readsp3b(fp,type,sats,ns,bfact,tsys,j++,opt,nav);
fclose(fp);
}
for (i=0;i<MAXEXFILE;i++) free(efiles[i]);
/* combine precise ephemeris */
if (nav->ne>0) combpeph(nav,opt);
}
/* read satellite antenna parameters -------------------------------------------
* read satellite antenna parameters
* args : char *file I antenna parameter file
* gtime_t time I time
* nav_t *nav IO navigation data
* return : status (1:ok,0:error)
* notes : only support antex format for the antenna parameter file
*-----------------------------------------------------------------------------*/
extern int readsap(const char *file, gtime_t time, nav_t *nav)
{
pcvs_t pcvs={0};
pcv_t pcv0={0},*pcv;
int i;
trace(3,"readsap : file=%s time=%s\n",file,time_str(time,0));
if (!readpcv(file,&pcvs)) return 0;
for (i=0;i<MAXSAT;i++) {
pcv=searchpcv(i+1,"",time,&pcvs);
nav->pcvs[i]=pcv?*pcv:pcv0;
}
free(pcvs.pcv);
return 1;
}
/* read dcb parameters file --------------------------------------------------*/
static int readdcbf(const char *file, nav_t *nav, const sta_t *sta)
{
FILE *fp;
double cbias;
char buff[256],str1[32],str2[32]="";
int i,j,sat,type=0;
trace(3,"readdcbf: file=%s\n",file);
if (!(fp=fopen(file,"r"))) {
trace(2,"dcb parameters file open error: %s\n",file);
return 0;
}
while (fgets(buff,sizeof(buff),fp)) {
if (strstr(buff,"DIFFERENTIAL (P1-P2) CODE BIASES")) type=1;
else if (strstr(buff,"DIFFERENTIAL (P1-C1) CODE BIASES")) type=2;
else if (strstr(buff,"DIFFERENTIAL (P2-C2) CODE BIASES")) type=3;
if (!type||sscanf(buff,"%s %s",str1,str2)<1) continue;
if ((cbias=str2num(buff,26,9))==0.0) continue;
if (sta&&(!strcmp(str1,"G")||!strcmp(str1,"R"))) { /* receiver dcb */
for (i=0;i<MAXRCV;i++) {
if (!strcmp(sta[i].name,str2)) break;
}
if (i<MAXRCV) {
j=!strcmp(str1,"G")?0:1;
nav->rbias[i][j][type-1]=cbias*1E-9*CLIGHT; /* ns -> m */
}
}
else if ((sat=satid2no(str1))) { /* satellite dcb */
nav->cbias[sat-1][type-1]=cbias*1E-9*CLIGHT; /* ns -> m */
}
}
fclose(fp);
return 1;
}
/* read dcb parameters ---------------------------------------------------------
* read differential code bias (dcb) parameters
* args : char *file I dcb parameters file (wild-card * expanded)
* nav_t *nav IO navigation data
* sta_t *sta I station info data to inport receiver dcb
* (NULL: no use)
* return : status (1:ok,0:error)
* notes : currently only p1-c1 bias of code *.dcb file
*-----------------------------------------------------------------------------*/
extern int readdcb(const char *file, nav_t *nav, const sta_t *sta)
{
int i,j,n;
char *efiles[MAXEXFILE]={0};
trace(3,"readdcb : file=%s\n",file);
for (i=0;i<MAXSAT;i++) for (j=0;j<3;j++) {
nav->cbias[i][j]=0.0;
}
for (i=0;i<MAXEXFILE;i++) {
if (!(efiles[i]=(char *)malloc(1024))) {
for (i--;i>=0;i--) free(efiles[i]);
return 0;
}
}
n=expath(file,efiles,MAXEXFILE);
for (i=0;i<n;i++) {
readdcbf(efiles[i],nav,sta);
}
for (i=0;i<MAXEXFILE;i++) free(efiles[i]);
return 1;
}
/* add satellite fcb ---------------------------------------------------------*/
static int addfcb(nav_t *nav, gtime_t ts, gtime_t te, int sat,
const double *bias, const double *std)
{
fcbd_t *nav_fcb;
int i,j;
if (nav->nf>0&&fabs(timediff(ts,nav->fcb[nav->nf-1].ts))<=1e-3) {
for (i=0;i<3;i++) {
nav->fcb[nav->nf-1].bias[sat-1][i]=bias[i];
nav->fcb[nav->nf-1].std [sat-1][i]=std [i];
}
return 1;
}
if (nav->nf>=nav->nfmax) {
nav->nfmax=nav->nfmax<=0?2048:nav->nfmax*2;
if (!(nav_fcb=(fcbd_t *)realloc(nav->fcb,sizeof(fcbd_t)*nav->nfmax))) {
free(nav->fcb); nav->nf=nav->nfmax=0;
return 0;
}
nav->fcb=nav_fcb;
}
for (i=0;i<MAXSAT;i++) for (j=0;j<3;j++) {
nav->fcb[nav->nf].bias[i][j]=nav->fcb[nav->nf].std[i][j]=0.0;
}
for (i=0;i<3;i++) {
nav->fcb[nav->nf].bias[sat-1][i]=bias[i];
nav->fcb[nav->nf].std [sat-1][i]=std [i];
}
nav->fcb[nav->nf ].ts=ts;
nav->fcb[nav->nf++].te=te;
return 1;
}
/* read satellite fcb file ---------------------------------------------------*/
static int readfcbf(const char *file, nav_t *nav)
{
FILE *fp;
gtime_t ts,te;
double ep1[6],ep2[6],bias[3]={0},std[3]={0};
char buff[1024],str[32],*p;
int sat;
trace(3,"readfcbf: file=%s\n",file);
if (!(fp=fopen(file,"r"))) {
trace(2,"fcb parameters file open error: %s\n",file);
return 0;
}
while (fgets(buff,sizeof(buff),fp)) {
if ((p=strchr(buff,'#'))) *p='\0';
if (sscanf(buff,"%lf/%lf/%lf %lf:%lf:%lf %lf/%lf/%lf %lf:%lf:%lf %s"
"%lf %lf %lf %lf %lf %lf",ep1,ep1+1,ep1+2,ep1+3,ep1+4,ep1+5,
ep2,ep2+1,ep2+2,ep2+3,ep2+4,ep2+5,str,bias,std,bias+1,std+1,
bias+2,std+2)<17) continue;
if (!(sat=satid2no(str))) continue;
ts=epoch2time(ep1);
te=epoch2time(ep2);
if (!addfcb(nav,ts,te,sat,bias,std)) return 0;
}
fclose(fp);
return 1;
}
/* compare satellite fcb -----------------------------------------------------*/
static int cmpfcb(const void *p1, const void *p2)
{
fcbd_t *q1=(fcbd_t *)p1,*q2=(fcbd_t *)p2;
double tt=timediff(q1->ts,q2->ts);
return tt<-1E-3?-1:(tt>1E-3?1:0);
}
/* read satellite fcb data -----------------------------------------------------
* read satellite fractional cycle bias (dcb) parameters
* args : char *file I fcb parameters file (wild-card * expanded)
* nav_t *nav IO navigation data
* return : status (1:ok,0:error)
* notes : fcb data appended to navigation data
*-----------------------------------------------------------------------------*/
extern int readfcb(const char *file, nav_t *nav)
{
char *efiles[MAXEXFILE]={0};
int i,n;
trace(3,"readfcb : file=%s\n",file);
for (i=0;i<MAXEXFILE;i++) {
if (!(efiles[i]=(char *)malloc(1024))) {
for (i--;i>=0;i--) free(efiles[i]);
return 0;
}
}
n=expath(file,efiles,MAXEXFILE);
for (i=0;i<n;i++) {
readfcbf(efiles[i],nav);
}
for (i=0;i<MAXEXFILE;i++) free(efiles[i]);
if (nav->nf>1) {
qsort(nav->fcb,nav->nf,sizeof(fcbd_t),cmpfcb);
}
return 1;
}
/* polynomial interpolation by Neville's algorithm ---------------------------*/
static double interppol(const double *x, double *y, int n)
{
int i,j;
for (j=1;j<n;j++) {
for (i=0;i<n-j;i++) {
y[i]=(x[i+j]*y[i]-x[i]*y[i+1])/(x[i+j]-x[i]);
}
}
return y[0];
}
/* satellite position by precise ephemeris -----------------------------------*/
static int pephpos(gtime_t time, int sat, const nav_t *nav, double *rs,
double *dts, double *vare, double *varc)
{
double t[NMAX+1],p[3][NMAX+1],c[2],*pos,std=0.0,s[3],sinl,cosl;
int i,j,k,index;
trace(4,"pephpos : time=%s sat=%2d\n",time_str(time,3),sat);
rs[0]=rs[1]=rs[2]=dts[0]=0.0;
if (nav->ne<NMAX+1||
timediff(time,nav->peph[0].time)<-MAXDTE||
timediff(time,nav->peph[nav->ne-1].time)>MAXDTE) {
trace(3,"no prec ephem %s sat=%2d\n",time_str(time,0),sat);
return 0;
}
/* binary search */
for (i=0,j=nav->ne-1;i<j;) {
k=(i+j)/2;
if (timediff(nav->peph[k].time,time)<0.0) i=k+1; else j=k;
}
index=i<=0?0:i-1;
/* polynomial interpolation for orbit */
i=index-(NMAX+1)/2;
if (i<0) i=0; else if (i+NMAX>=nav->ne) i=nav->ne-NMAX-1;
for (j=0;j<=NMAX;j++) {
t[j]=timediff(nav->peph[i+j].time,time);
if (norm(nav->peph[i+j].pos[sat-1],3)<=0.0) {
trace(3,"prec ephem outage %s sat=%2d\n",time_str(time,0),sat);
return 0;
}
}
for (j=0;j<=NMAX;j++) {
pos=nav->peph[i+j].pos[sat-1];
#if 0
p[0][j]=pos[0];
p[1][j]=pos[1];
#else
/* correciton for earh rotation ver.2.4.0 */
sinl=sin(OMGE*t[j]);
cosl=cos(OMGE*t[j]);
p[0][j]=cosl*pos[0]-sinl*pos[1];
p[1][j]=sinl*pos[0]+cosl*pos[1];
#endif
p[2][j]=pos[2];
}
for (i=0;i<3;i++) {
rs[i]=interppol(t,p[i],NMAX+1);
}
if (vare) {
for (i=0;i<3;i++) s[i]=nav->peph[index].std[sat-1][i];
std=norm(s,3);
/* extrapolation error for orbit */
if (t[0 ]>0.0) std+=EXTERR_EPH*SQR(t[0 ])/2.0;
else if (t[NMAX]<0.0) std+=EXTERR_EPH*SQR(t[NMAX])/2.0;
*vare=SQR(std);
}
/* linear interpolation for clock */
t[0]=timediff(time,nav->peph[index ].time);
t[1]=timediff(time,nav->peph[index+1].time);
c[0]=nav->peph[index ].pos[sat-1][3];
c[1]=nav->peph[index+1].pos[sat-1][3];
if (t[0]<=0.0) {
if ((dts[0]=c[0])!=0.0) {
std=nav->peph[index].std[sat-1][3]*CLIGHT-EXTERR_CLK*t[0];
}
}
else if (t[1]>=0.0) {
if ((dts[0]=c[1])!=0.0) {
std=nav->peph[index+1].std[sat-1][3]*CLIGHT+EXTERR_CLK*t[1];
}
}
else if (c[0]!=0.0&&c[1]!=0.0) {
dts[0]=(c[1]*t[0]-c[0]*t[1])/(t[0]-t[1]);
i=t[0]<-t[1]?0:1;
std=nav->peph[index+i].std[sat-1][3]+EXTERR_CLK*fabs(t[i]);
}
else {
dts[0]=0.0;
}
if (varc) *varc=SQR(std);
return 1;
}
/* satellite clock by precise clock ------------------------------------------*/
static int pephclk(gtime_t time, int sat, const nav_t *nav, double *dts,
double *varc)
{
double t[2],c[2],std;
int i,j,k,index;
trace(4,"pephclk : time=%s sat=%2d\n",time_str(time,3),sat);
if (nav->nc<2||
timediff(time,nav->pclk[0].time)<-MAXDTE||
timediff(time,nav->pclk[nav->nc-1].time)>MAXDTE) {
trace(3,"no prec clock %s sat=%2d\n",time_str(time,0),sat);
return 1;
}
/* binary search */
for (i=0,j=nav->nc-1;i<j;) {
k=(i+j)/2;
if (timediff(nav->pclk[k].time,time)<0.0) i=k+1; else j=k;
}
index=i<=0?0:i-1;
/* linear interpolation for clock */
t[0]=timediff(time,nav->pclk[index ].time);
t[1]=timediff(time,nav->pclk[index+1].time);
c[0]=nav->pclk[index ].clk[sat-1][0];
c[1]=nav->pclk[index+1].clk[sat-1][0];
if (t[0]<=0.0) {
if ((dts[0]=c[0])==0.0) return 0;
std=nav->pclk[index].std[sat-1][0]*CLIGHT-EXTERR_CLK*t[0];
}
else if (t[1]>=0.0) {
if ((dts[0]=c[1])==0.0) return 0;
std=nav->pclk[index+1].std[sat-1][0]*CLIGHT+EXTERR_CLK*t[1];
}
else if (c[0]!=0.0&&c[1]!=0.0) {
dts[0]=(c[1]*t[0]-c[0]*t[1])/(t[0]-t[1]);
i=t[0]<-t[1]?0:1;
std=nav->pclk[index+i].std[sat-1][0]*CLIGHT+EXTERR_CLK*fabs(t[i]);
}
else {
trace(3,"prec clock outage %s sat=%2d\n",time_str(time,0),sat);
return 0;
}
if (varc) *varc=SQR(std);
return 1;
}
/* satellite antenna phase center offset ---------------------------------------
* compute satellite antenna phase center offset in ecef
* args : gtime_t time I time (gpst)
* double *rs I satellite position and velocity (ecef)
* {x,y,z,vx,vy,vz} (m|m/s)
* int sat I satellite number
* nav_t *nav I navigation data
* double *dant I satellite antenna phase center offset (ecef)
* {dx,dy,dz} (m) (iono-free LC value)
* return : none
*-----------------------------------------------------------------------------*/
extern void satantoff(gtime_t time, const double *rs, int sat, const nav_t *nav,
double *dant)
{
const double *lam=nav->lam[sat-1];
const pcv_t *pcv=nav->pcvs+sat-1;
double ex[3],ey[3],ez[3],es[3],r[3],rsun[3],gmst,erpv[5]={0};
double gamma,C1,C2,dant1,dant2;
int i,j=0,k=1;
trace(4,"satantoff: time=%s sat=%2d\n",time_str(time,3),sat);
/* sun position in ecef */
sunmoonpos(gpst2utc(time),erpv,rsun,NULL,&gmst);
/* unit vectors of satellite fixed coordinates */
for (i=0;i<3;i++) r[i]=-rs[i];
if (!normv3(r,ez)) return;
for (i=0;i<3;i++) r[i]=rsun[i]-rs[i];
if (!normv3(r,es)) return;
cross3(ez,es,r);
if (!normv3(r,ey)) return;
cross3(ey,ez,ex);
if (NFREQ>=3&&(satsys(sat,NULL)&(SYS_GAL|SYS_SBS))) k=2;
if (NFREQ<2||lam[j]==0.0||lam[k]==0.0) return;
gamma=SQR(lam[k])/SQR(lam[j]);
C1=gamma/(gamma-1.0);
C2=-1.0 /(gamma-1.0);
/* iono-free LC */
for (i=0;i<3;i++) {
dant1=pcv->off[j][0]*ex[i]+pcv->off[j][1]*ey[i]+pcv->off[j][2]*ez[i];
dant2=pcv->off[k][0]*ex[i]+pcv->off[k][1]*ey[i]+pcv->off[k][2]*ez[i];
dant[i]=C1*dant1+C2*dant2;
}
}
/* satellite position/clock by precise ephemeris/clock -------------------------
* compute satellite position/clock with precise ephemeris/clock
* args : gtime_t time I time (gpst)
* int sat I satellite number
* nav_t *nav I navigation data
* int opt I sat postion option
* (0: center of mass, 1: antenna phase center)
* double *rs O sat position and velocity (ecef)
* {x,y,z,vx,vy,vz} (m|m/s)
* double *dts O sat clock {bias,drift} (s|s/s)
* double *var IO sat position and clock error variance (m)
* (NULL: no output)
* return : status (1:ok,0:error or data outage)
* notes : clock includes relativistic correction but does not contain code bias
* before calling the function, nav->peph, nav->ne, nav->pclk and
* nav->nc must be set by calling readsp3(), readrnx() or readrnxt()
* if precise clocks are not set, clocks in sp3 are used instead
*-----------------------------------------------------------------------------*/
extern int peph2pos(gtime_t time, int sat, const nav_t *nav, int opt,
double *rs, double *dts, double *var)
{
gtime_t time_tt;
double rss[3],rst[3],dtss[1],dtst[1],dant[3]={0},vare=0.0,varc=0.0,tt=1E-3;
int i;
trace(4,"peph2pos: time=%s sat=%2d opt=%d\n",time_str(time,3),sat,opt);
if (sat<=0||MAXSAT<sat) return 0;
/* satellite position and clock bias */
if (!pephpos(time,sat,nav,rss,dtss,&vare,&varc)||
!pephclk(time,sat,nav,dtss,&varc)) return 0;
time_tt=timeadd(time,tt);
if (!pephpos(time_tt,sat,nav,rst,dtst,NULL,NULL)||
!pephclk(time_tt,sat,nav,dtst,NULL)) return 0;
/* satellite antenna offset correction */
if (opt) {
satantoff(time,rss,sat,nav,dant);
}
for (i=0;i<3;i++) {
rs[i ]=rss[i]+dant[i];
rs[i+3]=(rst[i]-rss[i])/tt;
}
/* relativistic effect correction */
if (dtss[0]!=0.0) {
dts[0]=dtss[0]-2.0*dot(rs,rs+3,3)/CLIGHT/CLIGHT;
dts[1]=(dtst[0]-dtss[0])/tt;
}
else { /* no precise clock */
dts[0]=dts[1]=0.0;
}
if (var) *var=vare+varc;
return 1;
}