source: ntrip/trunk/BNS/bnseph.cpp@ 1891

Last change on this file since 1891 was 1882, checked in by mervart, 15 years ago

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File size: 19.7 KB
Line 
1/* -------------------------------------------------------------------------
2 * BKG NTRIP Server
3 * -------------------------------------------------------------------------
4 *
5 * Class: bnseph
6 *
7 * Purpose: Retrieve broadcast ephemeris from BNC
8 *
9 * Author: L. Mervart
10 *
11 * Created: 29-Mar-2008
12 *
13 * Changes:
14 *
15 * -----------------------------------------------------------------------*/
16
17#include <iostream>
18
19#include "bnseph.h"
20#include "bnsutils.h"
21#include "bnssettings.h"
22
23#define PI 3.1415926535898
24
25using namespace std;
26
27// Constructor
28////////////////////////////////////////////////////////////////////////////
29t_bnseph::t_bnseph(QObject* parent) : QThread(parent) {
30
31 this->setTerminationEnabled(true);
32
33 _socket = 0;
34
35 bnsSettings settings;
36
37 QIODevice::OpenMode oMode;
38 if (Qt::CheckState(settings.value("fileAppend").toInt()) == Qt::Checked) {
39 oMode = QIODevice::WriteOnly | QIODevice::Unbuffered | QIODevice::Append;
40 }
41 else {
42 oMode = QIODevice::WriteOnly | QIODevice::Unbuffered;
43 }
44
45 // Echo ephemeris into a file
46 // ---------------------------
47 QString echoFileName = settings.value("ephEcho").toString();
48 if (echoFileName.isEmpty()) {
49 _echoFile = 0;
50 _echoStream = 0;
51 }
52 else {
53 _echoFile = new QFile(echoFileName);
54 if (_echoFile->open(oMode)) {
55 _echoStream = new QTextStream(_echoFile);
56 }
57 else {
58 _echoStream = 0;
59 }
60 }
61}
62
63// Destructor
64////////////////////////////////////////////////////////////////////////////
65t_bnseph::~t_bnseph() {
66 delete _socket;
67 delete _echoStream;
68 delete _echoFile;
69}
70
71// Connect the Socket
72////////////////////////////////////////////////////////////////////////////
73void t_bnseph::reconnect() {
74
75 delete _socket;
76
77 bnsSettings settings;
78 QString host = settings.value("ephHost").toString();
79 if (host.isEmpty()) {
80 host = "localhost";
81 }
82 int port = settings.value("ephPort").toInt();
83
84 _socket = new QTcpSocket();
85 _socket->connectToHost(host, port);
86
87 const int timeOut = 10*1000; // 10 seconds
88 if (!_socket->waitForConnected(timeOut)) {
89// emit(newMessage("bnseph::run Connect Timeout"));
90 emit(newMessage("Ephemeris server: Connection timeout")); // weber
91 msleep(1000);
92 }
93}
94
95// Start
96////////////////////////////////////////////////////////////////////////////
97void t_bnseph::run() {
98
99//emit(newMessage("bnseph::run Start"));
100 emit(newMessage("Ephemeris server: Connection opened")); // weber
101
102 while (true) {
103 if (_socket == 0 || _socket->state() != QAbstractSocket::ConnectedState) {
104 reconnect();
105 }
106 if (_socket && _socket->state() == QAbstractSocket::ConnectedState) {
107 readEph();
108 }
109 else {
110 msleep(10);
111 }
112 }
113}
114
115// Read One Ephemeris
116////////////////////////////////////////////////////////////////////////////
117void t_bnseph::readEph() {
118
119 int nBytes = 0;
120 t_eph* eph = 0;
121
122 QByteArray line = waitForLine(_socket);
123
124 if (line.isEmpty()) {
125 return;
126 }
127
128 if (_echoStream) {
129 *_echoStream << line;
130 _echoStream->flush();
131 }
132
133 nBytes += line.length();
134
135 QTextStream in(line);
136 QString prn;
137
138 in >> prn;
139
140 int numlines = 0;
141 if (prn.indexOf('R') != -1) {
142 eph = new t_ephGlo();
143 numlines = 4;
144 }
145 else {
146 eph = new t_ephGPS();
147 numlines = 8;
148 }
149
150 QStringList lines;
151 lines << line;
152
153 for (int ii = 2; ii <= numlines; ii++) {
154 QByteArray line = waitForLine(_socket);
155 if (line.isEmpty()) {
156 delete eph;
157 return;
158 }
159
160 if (_echoStream) {
161 *_echoStream << line;
162 _echoStream->flush();
163 }
164
165 nBytes += line.length();
166 lines << line;
167 }
168
169 eph->read(lines);
170
171 emit(newEph(eph, nBytes));
172}
173
174// Compare Time
175////////////////////////////////////////////////////////////////////////////
176bool t_eph::isNewerThan(const t_eph* eph) const {
177 if (_GPSweek > eph->_GPSweek ||
178 (_GPSweek == eph->_GPSweek && _GPSweeks > eph->_GPSweeks)) {
179 return true;
180 }
181 else {
182 return false;
183 }
184}
185
186// Read GPS Ephemeris
187////////////////////////////////////////////////////////////////////////////
188void t_ephGPS::read(const QStringList& lines) {
189
190 for (int ii = 1; ii <= lines.size(); ii++) {
191 QTextStream in(lines.at(ii-1).toAscii());
192
193 if (ii == 1) {
194 double year, month, day, hour, minute, second;
195 in >> _prn >> year >> month >> day >> hour >> minute >> second
196 >> _clock_bias >> _clock_drift >> _clock_driftrate;
197
198 if (year < 100) year += 2000;
199
200 QDateTime* dateTime = new QDateTime(QDate(int(year), int(month), int(day)),
201 QTime(int(hour), int(minute), int(second)), Qt::UTC);
202
203 GPSweekFromDateAndTime(*dateTime, _GPSweek, _GPSweeks);
204
205 delete dateTime;
206
207 _TOC = _GPSweeks;
208 }
209 else if (ii == 2) {
210 in >> _IODE >> _Crs >> _Delta_n >> _M0;
211 }
212 else if (ii == 3) {
213 in >> _Cuc >> _e >> _Cus >> _sqrt_A;
214 }
215 else if (ii == 4) {
216 in >> _TOE >> _Cic >> _OMEGA0 >> _Cis;
217 }
218 else if (ii == 5) {
219 in >> _i0 >> _Crc >> _omega >> _OMEGADOT;
220 }
221 else if (ii == 6) {
222 double GPSweek;
223 in >> _IDOT >> _L2Codes >> GPSweek >> _L2PFlag;
224 }
225 else if (ii == 7) {
226 in >> _ura >> _health >> _TGD >> _IODC;
227 }
228 else if (ii == 8) {
229 in >> _TOW;
230 }
231 }
232}
233
234// Returns nearest integer value
235////////////////////////////////////////////////////////////////////////////
236static double NearestInt(double fl, double * remain)
237{
238 bool isneg = fl < 0.0;
239 double intval;
240 if(isneg) fl *= -1.0;
241 intval = (double)((unsigned long)(fl+0.5));
242 if(isneg) {fl *= -1.0; intval *= -1.0;}
243 if(remain)
244 *remain = fl-intval;
245 return intval;
246} /* NearestInt() */
247
248// Returns CRC24
249////////////////////////////////////////////////////////////////////////////
250static unsigned long CRC24(long size, const unsigned char *buf)
251{
252 unsigned long crc = 0;
253 int i;
254
255 while(size--)
256 {
257 crc ^= (*buf++) << (16);
258 for(i = 0; i < 8; i++)
259 {
260 crc <<= 1;
261 if(crc & 0x1000000)
262 crc ^= 0x01864cfb;
263 }
264 }
265 return crc;
266} /* CRC24 */
267
268// build up RTCM3 for GPS
269////////////////////////////////////////////////////////////////////////////
270
271#define GPSTOINT(type, value) static_cast<type>(NearestInt(value,0))
272
273#define GPSADDBITS(a, b) {bitbuffer = (bitbuffer<<(a)) \
274 |(GPSTOINT(long long,b)&((1ULL<<a)-1)); \
275 numbits += (a); \
276 while(numbits >= 8) { \
277 buffer[size++] = bitbuffer>>(numbits-8);numbits -= 8;}}
278#define GPSADDBITSFLOAT(a,b,c) {long long i = GPSTOINT(long long,(b)/(c)); \
279 GPSADDBITS(a,i)};
280
281int t_ephGPS::RTCM3(unsigned char *buffer)
282{
283
284 unsigned char *startbuffer = buffer;
285 buffer= buffer+3;
286 int size = 0;
287 int numbits = 0;
288 unsigned long long bitbuffer = 0;
289 if (_ura <= 2.40){
290 _ura = 0;
291 }
292 else if (_ura <= 3.40){
293 _ura = 1;
294 }
295 else if (_ura <= 6.85){
296 _ura = 2;
297 }
298 else if (_ura <= 9.65){
299 _ura = 3;
300 }
301 else if (_ura <= 13.65){
302 _ura = 4;
303 }
304 else if (_ura <= 24.00){
305 _ura = 5;
306 }
307 else if (_ura <= 48.00){
308 _ura = 6;
309 }
310 else if (_ura <= 96.00){
311 _ura = 7;
312 }
313 else if (_ura <= 192.00){
314 _ura = 8;
315 }
316 else if (_ura <= 384.00){
317 _ura = 9;
318 }
319 else if (_ura <= 768.00){
320 _ura = 10;
321 }
322 else if (_ura <= 1536.00){
323 _ura = 11;
324 }
325 else if (_ura <= 1536.00){
326 _ura = 12;
327 }
328 else if (_ura <= 2072.00){
329 _ura = 13;
330 }
331 else if (_ura <= 6144.00){
332 _ura = 14;
333 }
334 else{
335 _ura = 15;
336 }
337
338 GPSADDBITS(12, 1019)
339 GPSADDBITS(6,_prn.right((_prn.length()-1)).toInt())
340 GPSADDBITS(10, _GPSweek)
341 GPSADDBITS(4, _ura)
342 GPSADDBITS(2,_L2Codes)
343 GPSADDBITSFLOAT(14, _IDOT, PI/static_cast<double>(1<<30)
344 /static_cast<double>(1<<13))
345 GPSADDBITS(8, _IODE)
346 GPSADDBITS(16, static_cast<int>(_TOC)>>4)
347 GPSADDBITSFLOAT(8, _clock_driftrate, 1.0/static_cast<double>(1<<30)
348 /static_cast<double>(1<<25))
349 GPSADDBITSFLOAT(16, _clock_drift, 1.0/static_cast<double>(1<<30)
350 /static_cast<double>(1<<13))
351 GPSADDBITSFLOAT(22, _clock_bias, 1.0/static_cast<double>(1<<30)
352 /static_cast<double>(1<<1))
353 GPSADDBITS(10, _IODC)
354 GPSADDBITSFLOAT(16, _Crs, 1.0/static_cast<double>(1<<5))
355 GPSADDBITSFLOAT(16, _Delta_n, PI/static_cast<double>(1<<30)
356 /static_cast<double>(1<<13))
357 GPSADDBITSFLOAT(32, _M0, PI/static_cast<double>(1<<30)/static_cast<double>(1<<1))
358 GPSADDBITSFLOAT(16, _Cuc, 1.0/static_cast<double>(1<<29))
359 GPSADDBITSFLOAT(32, _e, 1.0/static_cast<double>(1<<30)/static_cast<double>(1<<3))
360 GPSADDBITSFLOAT(16, _Cus, 1.0/static_cast<double>(1<<29))
361 GPSADDBITSFLOAT(32, _sqrt_A, 1.0/static_cast<double>(1<<19))
362 GPSADDBITS(16, static_cast<int>(_TOE)>>4)
363 GPSADDBITSFLOAT(16, _Cic, 1.0/static_cast<double>(1<<29))
364 GPSADDBITSFLOAT(32, _OMEGA0, PI/static_cast<double>(1<<30)
365 /static_cast<double>(1<<1))
366 GPSADDBITSFLOAT(16, _Cis, 1.0/static_cast<double>(1<<29))
367 GPSADDBITSFLOAT(32, _i0, PI/static_cast<double>(1<<30)/static_cast<double>(1<<1))
368 GPSADDBITSFLOAT(16, _Crc, 1.0/static_cast<double>(1<<5))
369 GPSADDBITSFLOAT(32, _omega, PI/static_cast<double>(1<<30)
370 /static_cast<double>(1<<1))
371 GPSADDBITSFLOAT(24, _OMEGADOT, PI/static_cast<double>(1<<30)
372 /static_cast<double>(1<<13))
373 GPSADDBITSFLOAT(8, _TGD, 1.0/static_cast<double>(1<<30)/static_cast<double>(1<<1))
374 GPSADDBITS(6, _health)
375 GPSADDBITS(1, _L2PFlag)
376 GPSADDBITS(1, 0) /* GPS fit interval */
377
378 startbuffer[0]=0xD3;
379 startbuffer[1]=(size >> 8);
380 startbuffer[2]=size;
381 unsigned long i = CRC24(size+3, startbuffer);
382 buffer[size++] = i >> 16;
383 buffer[size++] = i >> 8;
384 buffer[size++] = i;
385 size += 3;
386 return size;
387}
388
389// Compute GPS Satellite Position
390////////////////////////////////////////////////////////////////////////////
391void t_ephGPS::position(int GPSweek, double GPSweeks, ColumnVector& xc,
392 ColumnVector& vv) const {
393
394 static const double secPerWeek = 7 * 86400.0;
395 static const double omegaEarth = 7292115.1467e-11;
396 static const double gmWGS = 398.6005e12;
397
398 if (xc.Nrows() < 4) {
399 xc.ReSize(4);
400 }
401 xc = 0.0;
402
403 if (vv.Nrows() < 3) {
404 vv.ReSize(3);
405 }
406 vv = 0.0;
407
408 double a0 = _sqrt_A * _sqrt_A;
409 if (a0 == 0) {
410 return;
411 }
412
413 double n0 = sqrt(gmWGS/(a0*a0*a0));
414 double tk = GPSweeks - _TOE;
415 if (GPSweek != _GPSweek) {
416 tk += (GPSweek - _GPSweek) * secPerWeek;
417 }
418 double n = n0 + _Delta_n;
419 double M = _M0 + n*tk;
420 double E = M;
421 double E_last;
422 do {
423 E_last = E;
424 E = M + _e*sin(E);
425 } while ( fabs(E-E_last)*a0 > 0.001 );
426 double v = 2.0*atan( sqrt( (1.0 + _e)/(1.0 - _e) )*tan( E/2 ) );
427 double u0 = v + _omega;
428 double sin2u0 = sin(2*u0);
429 double cos2u0 = cos(2*u0);
430 double r = a0*(1 - _e*cos(E)) + _Crc*cos2u0 + _Crs*sin2u0;
431 double i = _i0 + _IDOT*tk + _Cic*cos2u0 + _Cis*sin2u0;
432 double u = u0 + _Cuc*cos2u0 + _Cus*sin2u0;
433 double xp = r*cos(u);
434 double yp = r*sin(u);
435 double OM = _OMEGA0 + (_OMEGADOT - omegaEarth)*tk -
436 omegaEarth*_TOE;
437
438 double sinom = sin(OM);
439 double cosom = cos(OM);
440 double sini = sin(i);
441 double cosi = cos(i);
442 xc(1) = xp*cosom - yp*cosi*sinom;
443 xc(2) = xp*sinom + yp*cosi*cosom;
444 xc(3) = yp*sini;
445
446 double tc = GPSweeks - _TOC;
447 if (GPSweek != _GPSweek) {
448 tc += (GPSweek - _GPSweek) * secPerWeek;
449 }
450 xc(4) = _clock_bias + _clock_drift*tc + _clock_driftrate*tc*tc
451 - 4.442807633e-10 * _e * sqrt(a0) *sin(E);
452
453 // Velocity
454 // --------
455 double tanv2 = tan(v/2);
456 double dEdM = 1 / (1 - _e*cos(E));
457 double dotv = sqrt((1.0 + _e)/(1.0 - _e)) / cos(E/2)/cos(E/2) / (1 + tanv2*tanv2)
458 * dEdM * n;
459 double dotu = dotv + (-_Cuc*sin2u0 + _Cus*cos2u0)*2*dotv;
460 double dotom = _OMEGADOT - omegaEarth;
461 double doti = _IDOT + (-_Cic*sin2u0 + _Cis*cos2u0)*2*dotv;
462 double dotr = a0 * _e*sin(E) * dEdM * n
463 + (-_Crc*sin2u0 + _Crs*cos2u0)*2*dotv;
464 double dotx = dotr*cos(u) - r*sin(u)*dotu;
465 double doty = dotr*sin(u) + r*cos(u)*dotu;
466
467 vv(1) = cosom *dotx - cosi*sinom *doty // dX / dr
468 - xp*sinom*dotom - yp*cosi*cosom*dotom // dX / dOMEGA
469 + yp*sini*sinom*doti; // dX / di
470
471 vv(2) = sinom *dotx + cosi*cosom *doty
472 + xp*cosom*dotom - yp*cosi*sinom*dotom
473 - yp*sini*cosom*doti;
474
475 vv(3) = sini *doty + yp*cosi *doti;
476}
477
478// Read Glonass Ephemeris
479////////////////////////////////////////////////////////////////////////////
480void t_ephGlo::read(const QStringList& lines) {
481
482 for (int ii = 1; ii <= lines.size(); ii++) {
483 QTextStream in(lines.at(ii-1).toAscii());
484
485 if (ii == 1) {
486 double year, month, day, hour, minute, second;
487 in >> _prn >> year >> month >> day >> hour >> minute >> second
488 >> _tau >> _gamma >> _tki;
489
490 _tau = -_tau;
491
492 if (year < 100) year += 2000;
493
494 QDateTime* dateTime = new QDateTime(QDate(int(year), int(month), int(day)),
495 QTime(int(hour), int(minute), int(second)), Qt::UTC);
496
497 GPSweekFromDateAndTime(*dateTime, _GPSweek, _GPSweeks);
498
499 delete dateTime;
500
501 //// beg test
502 //// _gps_utc = 14.0;
503 //// end test
504
505 _GPSweeks += _gps_utc;
506 }
507 else if (ii == 2) {
508 in >>_x_pos >> _x_velocity >> _x_acceleration >> _health;
509 }
510 else if (ii == 3) {
511 in >>_y_pos >> _y_velocity >> _y_acceleration >> _frequency_number;
512 }
513 else if (ii == 4) {
514 in >>_z_pos >> _z_velocity >> _z_acceleration >> _E;
515 }
516 }
517
518 // Initialize status vector
519 // ------------------------
520 _tt = _GPSweeks;
521
522 _xv(1) = _x_pos * 1.e3;
523 _xv(2) = _y_pos * 1.e3;
524 _xv(3) = _z_pos * 1.e3;
525 _xv(4) = _x_velocity * 1.e3;
526 _xv(5) = _y_velocity * 1.e3;
527 _xv(6) = _z_velocity * 1.e3;
528}
529
530
531// build up RTCM3 for GLONASS
532////////////////////////////////////////////////////////////////////////////
533#define GLONASSTOINT(type, value) static_cast<type>(NearestInt(value,0))
534
535#define GLONASSADDBITS(a, b) {bitbuffer = (bitbuffer<<(a)) \
536 |(GLONASSTOINT(long long,b)&((1ULL<<(a))-1)); \
537 numbits += (a); \
538 while(numbits >= 8) { \
539 buffer[size++] = bitbuffer>>(numbits-8);numbits -= 8;}}
540#define GLONASSADDBITSFLOATM(a,b,c) {int s; long long i; \
541 if(b < 0.0) \
542 { \
543 s = 1; \
544 i = GLONASSTOINT(long long,(-b)/(c)); \
545 if(!i) s = 0; \
546 } \
547 else \
548 { \
549 s = 0; \
550 i = GLONASSTOINT(long long,(b)/(c)); \
551 } \
552 GLONASSADDBITS(1,s) \
553 GLONASSADDBITS(a-1,i)}
554
555int t_ephGlo::RTCM3(unsigned char *buffer)
556{
557
558 int size = 0;
559 int numbits = 0;
560 long long bitbuffer = 0;
561 unsigned char *startbuffer = buffer;
562 buffer= buffer+3;
563
564 GLONASSADDBITS(12, 1020)
565 GLONASSADDBITS(6, _prn.right((_prn.length()-1)).toInt())
566 GLONASSADDBITS(5, 7+_frequency_number)
567 GLONASSADDBITS(1, 0)
568 GLONASSADDBITS(1, 0)
569 GLONASSADDBITS(2, 0)
570 _tki=_tki+3*60*60;
571 GLONASSADDBITS(5, static_cast<int>(_tki)/(60*60))
572 GLONASSADDBITS(6, (static_cast<int>(_tki)/60)%60)
573 GLONASSADDBITS(1, (static_cast<int>(_tki)/30)%30)
574 GLONASSADDBITS(1, _health)
575 GLONASSADDBITS(1, 0)
576 unsigned long long timeofday = (static_cast<int>(_tt+3*60*60-_gps_utc)%86400);
577 GLONASSADDBITS(7, timeofday/60/15)
578 GLONASSADDBITSFLOATM(24, _x_velocity*1000, 1000.0/static_cast<double>(1<<20))
579 GLONASSADDBITSFLOATM(27, _x_pos*1000, 1000.0/static_cast<double>(1<<11))
580 GLONASSADDBITSFLOATM(5, _x_acceleration*1000, 1000.0/static_cast<double>(1<<30))
581 GLONASSADDBITSFLOATM(24, _y_velocity*1000, 1000.0/static_cast<double>(1<<20))
582 GLONASSADDBITSFLOATM(27, _y_pos*1000, 1000.0/static_cast<double>(1<<11))
583 GLONASSADDBITSFLOATM(5, _y_acceleration*1000, 1000.0/static_cast<double>(1<<30))
584 GLONASSADDBITSFLOATM(24, _z_velocity*1000, 1000.0/static_cast<double>(1<<20))
585 GLONASSADDBITSFLOATM(27,_z_pos*1000, 1000.0/static_cast<double>(1<<11))
586 GLONASSADDBITSFLOATM(5, _z_acceleration*1000, 1000.0/static_cast<double>(1<<30))
587 GLONASSADDBITS(1, 0)
588 GLONASSADDBITSFLOATM(11, _gamma, 1.0/static_cast<double>(1<<30)
589 /static_cast<double>(1<<10))
590 GLONASSADDBITS(2, 0) /* GLONASS-M P */
591 GLONASSADDBITS(1, 0) /* GLONASS-M ln(3) */
592 GLONASSADDBITSFLOATM(22, _tau, 1.0/static_cast<double>(1<<30))
593 GLONASSADDBITS(5, 0) /* GLONASS-M delta tau */
594 GLONASSADDBITS(5, _E)
595 GLONASSADDBITS(1, 0) /* GLONASS-M P4 */
596 GLONASSADDBITS(4, 0) /* GLONASS-M FT */
597 GLONASSADDBITS(11, 0) /* GLONASS-M NT */
598 GLONASSADDBITS(2, 0) /* GLONASS-M active? */
599 GLONASSADDBITS(1, 0) /* GLONASS additional data */
600 GLONASSADDBITS(11, 0) /* GLONASS NA */
601 GLONASSADDBITS(32, 0) /* GLONASS tau C */
602 GLONASSADDBITS(5, 0) /* GLONASS-M N4 */
603 GLONASSADDBITS(22, 0) /* GLONASS-M tau GPS */
604 GLONASSADDBITS(1, 0) /* GLONASS-M ln(5) */
605 GLONASSADDBITS(7, 0) /* Reserved */
606
607 startbuffer[0]=0xD3;
608 startbuffer[1]=(size >> 8);
609 startbuffer[2]=size;
610 unsigned long i = CRC24(size+3, startbuffer);
611 buffer[size++] = i >> 16;
612 buffer[size++] = i >> 8;
613 buffer[size++] = i;
614 size += 3;
615 return size;
616}
617
618// Derivative of the state vector using a simple force model (static)
619////////////////////////////////////////////////////////////////////////////
620ColumnVector t_ephGlo::glo_deriv(double /* tt */, const ColumnVector& xv) {
621
622 // State vector components
623 // -----------------------
624 ColumnVector rr = xv.rows(1,3);
625 ColumnVector vv = xv.rows(4,6);
626
627 // Acceleration
628 // ------------
629 static const double GM = 398.60044e12;
630 static const double AE = 6378136.0;
631 static const double OMEGA = 7292115.e-11;
632 static const double C20 = -1082.63e-6;
633
634 double rho = rr.norm_Frobenius();
635 double t1 = -GM/(rho*rho*rho);
636 double t2 = 3.0/2.0 * C20 * (GM*AE*AE) / (rho*rho*rho*rho*rho);
637 double t3 = OMEGA * OMEGA;
638 double t4 = 2.0 * OMEGA;
639 double z2 = rr(3) * rr(3);
640
641 // Vector of derivatives
642 // ---------------------
643 ColumnVector va(6);
644 va(1) = vv(1);
645 va(2) = vv(2);
646 va(3) = vv(3);
647 va(4) = (t1 + t2*(1.0-5.0*z2/(rho*rho)) + t3) * rr(1) + t4*vv(2);
648 va(5) = (t1 + t2*(1.0-5.0*z2/(rho*rho)) + t3) * rr(2) - t4*vv(1);
649 va(6) = (t1 + t2*(3.0-5.0*z2/(rho*rho)) ) * rr(3);
650
651 return va;
652}
653
654// Compute Glonass Satellite Position
655////////////////////////////////////////////////////////////////////////////
656void t_ephGlo::position(int GPSweek, double GPSweeks, ColumnVector& xc,
657 ColumnVector& vv) const {
658
659 static const double secPerWeek = 7 * 86400.0;
660 static const double nominalStep = 10.0;
661
662 double dtPos = GPSweeks - _tt;
663 if (GPSweek != _GPSweek) {
664 dtPos += (GPSweek - _GPSweek) * secPerWeek;
665 }
666
667 int nSteps = int(fabs(dtPos) / nominalStep) + 1;
668 double step = dtPos / nSteps;
669
670 for (int ii = 1; ii <= nSteps; ii++) {
671 _xv = rungeKutta4(_tt, _xv, step, glo_deriv);
672 _tt += step;
673 }
674
675 // Position and Velocity
676 // ---------------------
677 xc(1) = _xv(1);
678 xc(2) = _xv(2);
679 xc(3) = _xv(3);
680
681 vv(1) = _xv(4);
682 vv(2) = _xv(5);
683 vv(3) = _xv(6);
684
685 // Clock Correction
686 // ----------------
687 double dtClk = GPSweeks - _GPSweeks;
688 if (GPSweek != _GPSweek) {
689 dtClk += (GPSweek - _GPSweek) * secPerWeek;
690 }
691 xc(4) = -_tau + _gamma * dtClk;
692}
693
694// Glonass IOD
695////////////////////////////////////////////////////////////////////////////
696int t_ephGlo::IOD() const {
697 //// return int(fmod(_GPSweeks,86400.0)) / 600;
698
699 //// unsigned int tb = int(fmod(_GPSweeks,86400.0)) * 1000; // msec of day
700 unsigned int tb = int(fmod(_GPSweeks,86400.0)); //sec of day
701
702 // 5 LSBs of iod are equal to 5 LSBs of tb, remaining bits are zero
703 // ----------------------------------------------------------------
704 const int shift = sizeof(tb) * 8 - 5;
705 unsigned int iod = tb << shift;
706 return (iod >> shift);
707}
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