source: ntrip/trunk/BNC/RTCM3/ephemeris.cpp@ 3274

Last change on this file since 3274 was 3269, checked in by mervart, 14 years ago
File size: 21.7 KB
Line 
1#include <math.h>
2#include <sstream>
3#include <iostream>
4#include <iomanip>
5#include <cstring>
6
7#include <newmatio.h>
8
9#include "ephemeris.h"
10#include "bncutils.h"
11#include "timeutils.h"
12#include "bnctime.h"
13
14using namespace std;
15
16#define PI 3.1415926535898
17// Returns nearest integer value
18////////////////////////////////////////////////////////////////////////////
19static double NearestInt(double fl, double * remain)
20{
21 bool isneg = fl < 0.0;
22 double intval;
23 if(isneg) fl *= -1.0;
24 intval = (double)((unsigned long)(fl+0.5));
25 if(isneg) {fl *= -1.0; intval *= -1.0;}
26 if(remain)
27 *remain = fl-intval;
28 return intval;
29} /* NearestInt() */
30
31// Returns CRC24
32////////////////////////////////////////////////////////////////////////////
33static unsigned long CRC24(long size, const unsigned char *buf)
34{
35 unsigned long crc = 0;
36 int i;
37
38 while(size--)
39 {
40 crc ^= (*buf++) << (16);
41 for(i = 0; i < 8; i++)
42 {
43 crc <<= 1;
44 if(crc & 0x1000000)
45 crc ^= 0x01864cfb;
46 }
47 }
48 return crc;
49} /* CRC24 */
50
51//
52////////////////////////////////////////////////////////////////////////////
53bool t_eph::isNewerThan(const t_eph* eph) const {
54 if (_GPSweek > eph->_GPSweek ||
55 (_GPSweek == eph->_GPSweek && _GPSweeks > eph->_GPSweeks)) {
56 return true;
57 }
58 else {
59 return false;
60 }
61}
62
63// Set GPS Satellite Position
64////////////////////////////////////////////////////////////////////////////
65void t_ephGPS::set(const gpsephemeris* ee) {
66
67 _prn = QString("G%1").arg(ee->satellite, 2, 10, QChar('0'));
68
69 // TODO: check if following two lines are correct
70 _GPSweek = ee->GPSweek;
71 _GPSweeks = ee->TOE;
72
73 _TOW = ee->TOW;
74 _TOC = ee->TOC;
75 _TOE = ee->TOE;
76 _IODE = ee->IODE;
77 _IODC = ee->IODC;
78
79 _clock_bias = ee->clock_bias ;
80 _clock_drift = ee->clock_drift ;
81 _clock_driftrate = ee->clock_driftrate;
82
83 _Crs = ee->Crs;
84 _Delta_n = ee->Delta_n;
85 _M0 = ee->M0;
86 _Cuc = ee->Cuc;
87 _e = ee->e;
88 _Cus = ee->Cus;
89 _sqrt_A = ee->sqrt_A;
90 _Cic = ee->Cic;
91 _OMEGA0 = ee->OMEGA0;
92 _Cis = ee->Cis;
93 _i0 = ee->i0;
94 _Crc = ee->Crc;
95 _omega = ee->omega;
96 _OMEGADOT = ee->OMEGADOT;
97 _IDOT = ee->IDOT;
98
99 _TGD = ee->TGD;
100}
101
102// Compute GPS Satellite Position (virtual)
103////////////////////////////////////////////////////////////////////////////
104void t_ephGPS::position(int GPSweek, double GPSweeks,
105 double* xc,
106 double* vv) const {
107
108 static const double secPerWeek = 7 * 86400.0;
109 static const double omegaEarth = 7292115.1467e-11;
110 static const double gmWGS = 398.6005e12;
111
112 memset(xc, 0, 4*sizeof(double));
113 memset(vv, 0, 3*sizeof(double));
114
115 double a0 = _sqrt_A * _sqrt_A;
116 if (a0 == 0) {
117 return;
118 }
119
120 double n0 = sqrt(gmWGS/(a0*a0*a0));
121 double tk = GPSweeks - _TOE;
122 if (GPSweek != _GPSweek) {
123 tk += (GPSweek - _GPSweek) * secPerWeek;
124 }
125 double n = n0 + _Delta_n;
126 double M = _M0 + n*tk;
127 double E = M;
128 double E_last;
129 do {
130 E_last = E;
131 E = M + _e*sin(E);
132 } while ( fabs(E-E_last)*a0 > 0.001 );
133 double v = 2.0*atan( sqrt( (1.0 + _e)/(1.0 - _e) )*tan( E/2 ) );
134 double u0 = v + _omega;
135 double sin2u0 = sin(2*u0);
136 double cos2u0 = cos(2*u0);
137 double r = a0*(1 - _e*cos(E)) + _Crc*cos2u0 + _Crs*sin2u0;
138 double i = _i0 + _IDOT*tk + _Cic*cos2u0 + _Cis*sin2u0;
139 double u = u0 + _Cuc*cos2u0 + _Cus*sin2u0;
140 double xp = r*cos(u);
141 double yp = r*sin(u);
142 double OM = _OMEGA0 + (_OMEGADOT - omegaEarth)*tk -
143 omegaEarth*_TOE;
144
145 double sinom = sin(OM);
146 double cosom = cos(OM);
147 double sini = sin(i);
148 double cosi = cos(i);
149 xc[0] = xp*cosom - yp*cosi*sinom;
150 xc[1] = xp*sinom + yp*cosi*cosom;
151 xc[2] = yp*sini;
152
153 double tc = GPSweeks - _TOC;
154 if (GPSweek != _GPSweek) {
155 tc += (GPSweek - _GPSweek) * secPerWeek;
156 }
157 xc[3] = _clock_bias + _clock_drift*tc + _clock_driftrate*tc*tc;
158
159 // Velocity
160 // --------
161 double tanv2 = tan(v/2);
162 double dEdM = 1 / (1 - _e*cos(E));
163 double dotv = sqrt((1.0 + _e)/(1.0 - _e)) / cos(E/2)/cos(E/2) / (1 + tanv2*tanv2)
164 * dEdM * n;
165 double dotu = dotv + (-_Cuc*sin2u0 + _Cus*cos2u0)*2*dotv;
166 double dotom = _OMEGADOT - omegaEarth;
167 double doti = _IDOT + (-_Cic*sin2u0 + _Cis*cos2u0)*2*dotv;
168 double dotr = a0 * _e*sin(E) * dEdM * n
169 + (-_Crc*sin2u0 + _Crs*cos2u0)*2*dotv;
170 double dotx = dotr*cos(u) - r*sin(u)*dotu;
171 double doty = dotr*sin(u) + r*cos(u)*dotu;
172
173 vv[0] = cosom *dotx - cosi*sinom *doty // dX / dr
174 - xp*sinom*dotom - yp*cosi*cosom*dotom // dX / dOMEGA
175 + yp*sini*sinom*doti; // dX / di
176
177 vv[1] = sinom *dotx + cosi*cosom *doty
178 + xp*cosom*dotom - yp*cosi*sinom*dotom
179 - yp*sini*cosom*doti;
180
181 vv[2] = sini *doty + yp*cosi *doti;
182
183 // Relativistic Correction
184 // -----------------------
185 // xc(4) -= 4.442807633e-10 * _e * sqrt(a0) *sin(E);
186 xc[3] -= 2.0 * (xc[0]*vv[0] + xc[1]*vv[1] + xc[2]*vv[2]) / t_CST::c / t_CST::c;
187}
188
189// build up RTCM3 for GPS
190////////////////////////////////////////////////////////////////////////////
191#define GPSTOINT(type, value) static_cast<type>(NearestInt(value,0))
192
193#define GPSADDBITS(a, b) {bitbuffer = (bitbuffer<<(a)) \
194 |(GPSTOINT(long long,b)&((1ULL<<a)-1)); \
195 numbits += (a); \
196 while(numbits >= 8) { \
197 buffer[size++] = bitbuffer>>(numbits-8);numbits -= 8;}}
198#define GPSADDBITSFLOAT(a,b,c) {long long i = GPSTOINT(long long,(b)/(c)); \
199 GPSADDBITS(a,i)};
200
201int t_ephGPS::RTCM3(unsigned char *buffer)
202{
203
204 unsigned char *startbuffer = buffer;
205 buffer= buffer+3;
206 int size = 0;
207 int numbits = 0;
208 unsigned long long bitbuffer = 0;
209 if (_ura <= 2.40){
210 _ura = 0;
211 }
212 else if (_ura <= 3.40){
213 _ura = 1;
214 }
215 else if (_ura <= 6.85){
216 _ura = 2;
217 }
218 else if (_ura <= 9.65){
219 _ura = 3;
220 }
221 else if (_ura <= 13.65){
222 _ura = 4;
223 }
224 else if (_ura <= 24.00){
225 _ura = 5;
226 }
227 else if (_ura <= 48.00){
228 _ura = 6;
229 }
230 else if (_ura <= 96.00){
231 _ura = 7;
232 }
233 else if (_ura <= 192.00){
234 _ura = 8;
235 }
236 else if (_ura <= 384.00){
237 _ura = 9;
238 }
239 else if (_ura <= 768.00){
240 _ura = 10;
241 }
242 else if (_ura <= 1536.00){
243 _ura = 11;
244 }
245 else if (_ura <= 1536.00){
246 _ura = 12;
247 }
248 else if (_ura <= 2072.00){
249 _ura = 13;
250 }
251 else if (_ura <= 6144.00){
252 _ura = 14;
253 }
254 else{
255 _ura = 15;
256 }
257
258 GPSADDBITS(12, 1019)
259 GPSADDBITS(6,_prn.right((_prn.length()-1)).toInt())
260 GPSADDBITS(10, _GPSweek)
261 GPSADDBITS(4, _ura)
262 GPSADDBITS(2,_L2Codes)
263 GPSADDBITSFLOAT(14, _IDOT, PI/static_cast<double>(1<<30)
264 /static_cast<double>(1<<13))
265 GPSADDBITS(8, _IODE)
266 GPSADDBITS(16, static_cast<int>(_TOC)>>4)
267 GPSADDBITSFLOAT(8, _clock_driftrate, 1.0/static_cast<double>(1<<30)
268 /static_cast<double>(1<<25))
269 GPSADDBITSFLOAT(16, _clock_drift, 1.0/static_cast<double>(1<<30)
270 /static_cast<double>(1<<13))
271 GPSADDBITSFLOAT(22, _clock_bias, 1.0/static_cast<double>(1<<30)
272 /static_cast<double>(1<<1))
273 GPSADDBITS(10, _IODC)
274 GPSADDBITSFLOAT(16, _Crs, 1.0/static_cast<double>(1<<5))
275 GPSADDBITSFLOAT(16, _Delta_n, PI/static_cast<double>(1<<30)
276 /static_cast<double>(1<<13))
277 GPSADDBITSFLOAT(32, _M0, PI/static_cast<double>(1<<30)/static_cast<double>(1<<1))
278 GPSADDBITSFLOAT(16, _Cuc, 1.0/static_cast<double>(1<<29))
279 GPSADDBITSFLOAT(32, _e, 1.0/static_cast<double>(1<<30)/static_cast<double>(1<<3))
280 GPSADDBITSFLOAT(16, _Cus, 1.0/static_cast<double>(1<<29))
281 GPSADDBITSFLOAT(32, _sqrt_A, 1.0/static_cast<double>(1<<19))
282 GPSADDBITS(16, static_cast<int>(_TOE)>>4)
283 GPSADDBITSFLOAT(16, _Cic, 1.0/static_cast<double>(1<<29))
284 GPSADDBITSFLOAT(32, _OMEGA0, PI/static_cast<double>(1<<30)
285 /static_cast<double>(1<<1))
286 GPSADDBITSFLOAT(16, _Cis, 1.0/static_cast<double>(1<<29))
287 GPSADDBITSFLOAT(32, _i0, PI/static_cast<double>(1<<30)/static_cast<double>(1<<1))
288 GPSADDBITSFLOAT(16, _Crc, 1.0/static_cast<double>(1<<5))
289 GPSADDBITSFLOAT(32, _omega, PI/static_cast<double>(1<<30)
290 /static_cast<double>(1<<1))
291 GPSADDBITSFLOAT(24, _OMEGADOT, PI/static_cast<double>(1<<30)
292 /static_cast<double>(1<<13))
293 GPSADDBITSFLOAT(8, _TGD, 1.0/static_cast<double>(1<<30)/static_cast<double>(1<<1))
294 GPSADDBITS(6, _health)
295 GPSADDBITS(1, _L2PFlag)
296 GPSADDBITS(1, 0) /* GPS fit interval */
297
298 startbuffer[0]=0xD3;
299 startbuffer[1]=(size >> 8);
300 startbuffer[2]=size;
301 unsigned long i = CRC24(size+3, startbuffer);
302 buffer[size++] = i >> 16;
303 buffer[size++] = i >> 8;
304 buffer[size++] = i;
305 size += 3;
306 return size;
307}
308
309// Derivative of the state vector using a simple force model (static)
310////////////////////////////////////////////////////////////////////////////
311ColumnVector t_ephGlo::glo_deriv(double /* tt */, const ColumnVector& xv,
312 double* acc) {
313
314 // State vector components
315 // -----------------------
316 ColumnVector rr = xv.rows(1,3);
317 ColumnVector vv = xv.rows(4,6);
318
319 // Acceleration
320 // ------------
321 static const double GM = 398.60044e12;
322 static const double AE = 6378136.0;
323 static const double OMEGA = 7292115.e-11;
324 static const double C20 = -1082.6257e-6;
325
326 double rho = rr.norm_Frobenius();
327 double t1 = -GM/(rho*rho*rho);
328 double t2 = 3.0/2.0 * C20 * (GM*AE*AE) / (rho*rho*rho*rho*rho);
329 double t3 = OMEGA * OMEGA;
330 double t4 = 2.0 * OMEGA;
331 double z2 = rr(3) * rr(3);
332
333 // Vector of derivatives
334 // ---------------------
335 ColumnVector va(6);
336 va(1) = vv(1);
337 va(2) = vv(2);
338 va(3) = vv(3);
339 va(4) = (t1 + t2*(1.0-5.0*z2/(rho*rho)) + t3) * rr(1) + t4*vv(2) + acc[0];
340 va(5) = (t1 + t2*(1.0-5.0*z2/(rho*rho)) + t3) * rr(2) - t4*vv(1) + acc[1];
341 va(6) = (t1 + t2*(3.0-5.0*z2/(rho*rho)) ) * rr(3) + acc[2];
342
343 return va;
344}
345
346// Compute Glonass Satellite Position (virtual)
347////////////////////////////////////////////////////////////////////////////
348void t_ephGlo::position(int GPSweek, double GPSweeks,
349 double* xc, double* vv) const {
350
351 static const double secPerWeek = 7 * 86400.0;
352 static const double nominalStep = 10.0;
353
354 memset(xc, 0, 4*sizeof(double));
355 memset(vv, 0, 3*sizeof(double));
356
357 double dtPos = GPSweeks - _tt;
358 if (GPSweek != _GPSweek) {
359 dtPos += (GPSweek - _GPSweek) * secPerWeek;
360 }
361
362 int nSteps = int(fabs(dtPos) / nominalStep) + 1;
363 double step = dtPos / nSteps;
364
365 double acc[3];
366 acc[0] = _x_acceleration * 1.e3;
367 acc[1] = _y_acceleration * 1.e3;
368 acc[2] = _z_acceleration * 1.e3;
369 for (int ii = 1; ii <= nSteps; ii++) {
370 _xv = rungeKutta4(_tt, _xv, step, acc, glo_deriv);
371 _tt += step;
372 }
373
374 // Position and Velocity
375 // ---------------------
376 xc[0] = _xv(1);
377 xc[1] = _xv(2);
378 xc[2] = _xv(3);
379
380 vv[0] = _xv(4);
381 vv[1] = _xv(5);
382 vv[2] = _xv(6);
383
384 // Clock Correction
385 // ----------------
386 double dtClk = GPSweeks - _GPSweeks;
387 if (GPSweek != _GPSweek) {
388 dtClk += (GPSweek - _GPSweek) * secPerWeek;
389 }
390 xc[3] = -_tau + _gamma * dtClk;
391}
392
393// IOD of Glonass Ephemeris (virtual)
394////////////////////////////////////////////////////////////////////////////
395int t_ephGlo::IOD() const {
396
397 bool old = false;
398
399 if (old) { // 5 LSBs of iod are equal to 5 LSBs of tb
400 unsigned int tb = int(fmod(_GPSweeks,86400.0)); //sec of day
401 const int shift = sizeof(tb) * 8 - 5;
402 unsigned int iod = tb << shift;
403 return (iod >> shift);
404 }
405 else {
406 bncTime tGPS(_GPSweek, _GPSweeks);
407 int hlpWeek = _GPSweek;
408 int hlpSec = int(_GPSweeks);
409 int hlpMsec = int(_GPSweeks * 1000);
410 updatetime(&hlpWeek, &hlpSec, hlpMsec, 0);
411 bncTime tHlp(hlpWeek, hlpSec);
412 double diffSec = tGPS - tHlp;
413 bncTime tMoscow = tGPS + diffSec;
414 return int(tMoscow.daysec() / 900);
415 }
416}
417
418// Set Glonass Ephemeris
419////////////////////////////////////////////////////////////////////////////
420void t_ephGlo::set(const glonassephemeris* ee) {
421
422 _prn = QString("R%1").arg(ee->almanac_number, 2, 10, QChar('0'));
423
424 int ww = ee->GPSWeek;
425 int tow = ee->GPSTOW;
426 updatetime(&ww, &tow, ee->tb*1000, 0); // Moscow -> GPS
427
428 // Check the day once more
429 // -----------------------
430 {
431 const double secPerDay = 24 * 3600.0;
432 const double secPerWeek = 7 * secPerDay;
433 int ww_old = ww;
434 int tow_old = tow;
435 int currentWeek;
436 double currentSec;
437 currentGPSWeeks(currentWeek, currentSec);
438 bncTime currentTime(currentWeek, currentSec);
439 bncTime hTime(ww, (double) tow);
440
441 bool changed = false;
442 if (hTime - currentTime > secPerDay/2.0) {
443 changed = true;
444 tow -= secPerDay;
445 if (tow < 0) {
446 tow += secPerWeek;
447 ww -= 1;
448 }
449 }
450 else if (hTime - currentTime < -secPerDay/2.0) {
451 changed = true;
452 tow += secPerDay;
453 if (tow > secPerWeek) {
454 tow -= secPerWeek;
455 ww += 1;
456 }
457 }
458
459 if (changed) {
460 bncTime newHTime(ww, (double) tow);
461 cout << "GLONASS " << ee->almanac_number << " Time Changed at "
462 << currentTime.datestr() << " " << currentTime.timestr()
463 << endl
464 << "old: " << hTime.datestr() << " " << hTime.timestr()
465 << endl
466 << "new: " << newHTime.datestr() << " " << newHTime.timestr()
467 << endl
468 << "eph: " << ee->GPSWeek << " " << ee->GPSTOW << " " << ee->tb
469 << endl
470 << "ww, tow (old): " << ww_old << " " << tow_old
471 << endl
472 << "ww, tow (new): " << ww << " " << tow
473 << endl << endl;
474 }
475 }
476
477 bncTime hlpTime(ww, (double) tow);
478 unsigned year, month, day;
479 hlpTime.civil_date(year, month, day);
480 _gps_utc = gnumleap(year, month, day);
481
482 _GPSweek = ww;
483 _GPSweeks = tow;
484 _E = ee->E;
485 _tau = ee->tau;
486 _gamma = ee->gamma;
487 _x_pos = ee->x_pos;
488 _x_velocity = ee->x_velocity;
489 _x_acceleration = ee->x_acceleration;
490 _y_pos = ee->y_pos;
491 _y_velocity = ee->y_velocity;
492 _y_acceleration = ee->y_acceleration;
493 _z_pos = ee->z_pos;
494 _z_velocity = ee->z_velocity;
495 _z_acceleration = ee->z_acceleration;
496 _health = 0;
497 _frequency_number = ee->frequency_number;
498 _tki = ee->tk-3*60*60; if (_tki < 0) _tki += 86400;
499
500 // Initialize status vector
501 // ------------------------
502 _tt = _GPSweeks;
503
504 _xv(1) = _x_pos * 1.e3;
505 _xv(2) = _y_pos * 1.e3;
506 _xv(3) = _z_pos * 1.e3;
507 _xv(4) = _x_velocity * 1.e3;
508 _xv(5) = _y_velocity * 1.e3;
509 _xv(6) = _z_velocity * 1.e3;
510}
511
512// build up RTCM3 for GLONASS
513////////////////////////////////////////////////////////////////////////////
514#define GLONASSTOINT(type, value) static_cast<type>(NearestInt(value,0))
515
516#define GLONASSADDBITS(a, b) {bitbuffer = (bitbuffer<<(a)) \
517 |(GLONASSTOINT(long long,b)&((1ULL<<(a))-1)); \
518 numbits += (a); \
519 while(numbits >= 8) { \
520 buffer[size++] = bitbuffer>>(numbits-8);numbits -= 8;}}
521#define GLONASSADDBITSFLOATM(a,b,c) {int s; long long i; \
522 if(b < 0.0) \
523 { \
524 s = 1; \
525 i = GLONASSTOINT(long long,(-b)/(c)); \
526 if(!i) s = 0; \
527 } \
528 else \
529 { \
530 s = 0; \
531 i = GLONASSTOINT(long long,(b)/(c)); \
532 } \
533 GLONASSADDBITS(1,s) \
534 GLONASSADDBITS(a-1,i)}
535
536int t_ephGlo::RTCM3(unsigned char *buffer)
537{
538
539 int size = 0;
540 int numbits = 0;
541 long long bitbuffer = 0;
542 unsigned char *startbuffer = buffer;
543 buffer= buffer+3;
544
545 GLONASSADDBITS(12, 1020)
546 GLONASSADDBITS(6, _prn.right((_prn.length()-1)).toInt())
547 GLONASSADDBITS(5, 7+_frequency_number)
548 GLONASSADDBITS(1, 0)
549 GLONASSADDBITS(1, 0)
550 GLONASSADDBITS(2, 0)
551 _tki=_tki+3*60*60;
552 GLONASSADDBITS(5, static_cast<int>(_tki)/(60*60))
553 GLONASSADDBITS(6, (static_cast<int>(_tki)/60)%60)
554 GLONASSADDBITS(1, (static_cast<int>(_tki)/30)%30)
555 GLONASSADDBITS(1, _health)
556 GLONASSADDBITS(1, 0)
557 unsigned long long timeofday = (static_cast<int>(_tt+3*60*60-_gps_utc)%86400);
558 GLONASSADDBITS(7, timeofday/60/15)
559 GLONASSADDBITSFLOATM(24, _x_velocity*1000, 1000.0/static_cast<double>(1<<20))
560 GLONASSADDBITSFLOATM(27, _x_pos*1000, 1000.0/static_cast<double>(1<<11))
561 GLONASSADDBITSFLOATM(5, _x_acceleration*1000, 1000.0/static_cast<double>(1<<30))
562 GLONASSADDBITSFLOATM(24, _y_velocity*1000, 1000.0/static_cast<double>(1<<20))
563 GLONASSADDBITSFLOATM(27, _y_pos*1000, 1000.0/static_cast<double>(1<<11))
564 GLONASSADDBITSFLOATM(5, _y_acceleration*1000, 1000.0/static_cast<double>(1<<30))
565 GLONASSADDBITSFLOATM(24, _z_velocity*1000, 1000.0/static_cast<double>(1<<20))
566 GLONASSADDBITSFLOATM(27,_z_pos*1000, 1000.0/static_cast<double>(1<<11))
567 GLONASSADDBITSFLOATM(5, _z_acceleration*1000, 1000.0/static_cast<double>(1<<30))
568 GLONASSADDBITS(1, 0)
569 GLONASSADDBITSFLOATM(11, _gamma, 1.0/static_cast<double>(1<<30)
570 /static_cast<double>(1<<10))
571 GLONASSADDBITS(2, 0) /* GLONASS-M P */
572 GLONASSADDBITS(1, 0) /* GLONASS-M ln(3) */
573 GLONASSADDBITSFLOATM(22, _tau, 1.0/static_cast<double>(1<<30))
574 GLONASSADDBITS(5, 0) /* GLONASS-M delta tau */
575 GLONASSADDBITS(5, _E)
576 GLONASSADDBITS(1, 0) /* GLONASS-M P4 */
577 GLONASSADDBITS(4, 0) /* GLONASS-M FT */
578 GLONASSADDBITS(11, 0) /* GLONASS-M NT */
579 GLONASSADDBITS(2, 0) /* GLONASS-M active? */
580 GLONASSADDBITS(1, 0) /* GLONASS additional data */
581 GLONASSADDBITS(11, 0) /* GLONASS NA */
582 GLONASSADDBITS(32, 0) /* GLONASS tau C */
583 GLONASSADDBITS(5, 0) /* GLONASS-M N4 */
584 GLONASSADDBITS(22, 0) /* GLONASS-M tau GPS */
585 GLONASSADDBITS(1, 0) /* GLONASS-M ln(5) */
586 GLONASSADDBITS(7, 0) /* Reserved */
587
588 startbuffer[0]=0xD3;
589 startbuffer[1]=(size >> 8);
590 startbuffer[2]=size;
591 unsigned long i = CRC24(size+3, startbuffer);
592 buffer[size++] = i >> 16;
593 buffer[size++] = i >> 8;
594 buffer[size++] = i;
595 size += 3;
596 return size;
597}
598
599// Set Galileo Satellite Position
600////////////////////////////////////////////////////////////////////////////
601void t_ephGal::set(const galileoephemeris* ee) {
602
603 _prn = QString("E%1").arg(ee->satellite, 2, 10, QChar('0'));
604
605 _GPSweek = ee->Week;
606 _GPSweeks = ee->TOE;
607
608 _TOC = ee->TOC;
609 _TOE = ee->TOE;
610 _IODnav = ee->IODnav;
611
612 _clock_bias = ee->clock_bias ;
613 _clock_drift = ee->clock_drift ;
614 _clock_driftrate = ee->clock_driftrate;
615
616 _Crs = ee->Crs;
617 _Delta_n = ee->Delta_n;
618 _M0 = ee->M0;
619 _Cuc = ee->Cuc;
620 _e = ee->e;
621 _Cus = ee->Cus;
622 _sqrt_A = ee->sqrt_A;
623 _Cic = ee->Cic;
624 _OMEGA0 = ee->OMEGA0;
625 _Cis = ee->Cis;
626 _i0 = ee->i0;
627 _Crc = ee->Crc;
628 _omega = ee->omega;
629 _OMEGADOT = ee->OMEGADOT;
630 _IDOT = ee->IDOT;
631}
632
633// Compute Galileo Satellite Position (virtual)
634////////////////////////////////////////////////////////////////////////////
635void t_ephGal::position(int GPSweek, double GPSweeks,
636 double* xc,
637 double* vv) const {
638
639 static const double secPerWeek = 7 * 86400.0;
640 static const double omegaEarth = 7292115.1467e-11;
641 static const double gmWGS = 398.6005e12;
642
643 memset(xc, 0, 4*sizeof(double));
644 memset(vv, 0, 3*sizeof(double));
645
646 double a0 = _sqrt_A * _sqrt_A;
647 if (a0 == 0) {
648 return;
649 }
650
651 double n0 = sqrt(gmWGS/(a0*a0*a0));
652 double tk = GPSweeks - _TOE;
653 if (GPSweek != _GPSweek) {
654 tk += (GPSweek - _GPSweek) * secPerWeek;
655 }
656 double n = n0 + _Delta_n;
657 double M = _M0 + n*tk;
658 double E = M;
659 double E_last;
660 do {
661 E_last = E;
662 E = M + _e*sin(E);
663 } while ( fabs(E-E_last)*a0 > 0.001 );
664 double v = 2.0*atan( sqrt( (1.0 + _e)/(1.0 - _e) )*tan( E/2 ) );
665 double u0 = v + _omega;
666 double sin2u0 = sin(2*u0);
667 double cos2u0 = cos(2*u0);
668 double r = a0*(1 - _e*cos(E)) + _Crc*cos2u0 + _Crs*sin2u0;
669 double i = _i0 + _IDOT*tk + _Cic*cos2u0 + _Cis*sin2u0;
670 double u = u0 + _Cuc*cos2u0 + _Cus*sin2u0;
671 double xp = r*cos(u);
672 double yp = r*sin(u);
673 double OM = _OMEGA0 + (_OMEGADOT - omegaEarth)*tk -
674 omegaEarth*_TOE;
675
676 double sinom = sin(OM);
677 double cosom = cos(OM);
678 double sini = sin(i);
679 double cosi = cos(i);
680 xc[0] = xp*cosom - yp*cosi*sinom;
681 xc[1] = xp*sinom + yp*cosi*cosom;
682 xc[2] = yp*sini;
683
684 double tc = GPSweeks - _TOC;
685 if (GPSweek != _GPSweek) {
686 tc += (GPSweek - _GPSweek) * secPerWeek;
687 }
688 xc[3] = _clock_bias + _clock_drift*tc + _clock_driftrate*tc*tc;
689
690 // Velocity
691 // --------
692 double tanv2 = tan(v/2);
693 double dEdM = 1 / (1 - _e*cos(E));
694 double dotv = sqrt((1.0 + _e)/(1.0 - _e)) / cos(E/2)/cos(E/2) / (1 + tanv2*tanv2)
695 * dEdM * n;
696 double dotu = dotv + (-_Cuc*sin2u0 + _Cus*cos2u0)*2*dotv;
697 double dotom = _OMEGADOT - omegaEarth;
698 double doti = _IDOT + (-_Cic*sin2u0 + _Cis*cos2u0)*2*dotv;
699 double dotr = a0 * _e*sin(E) * dEdM * n
700 + (-_Crc*sin2u0 + _Crs*cos2u0)*2*dotv;
701 double dotx = dotr*cos(u) - r*sin(u)*dotu;
702 double doty = dotr*sin(u) + r*cos(u)*dotu;
703
704 vv[0] = cosom *dotx - cosi*sinom *doty // dX / dr
705 - xp*sinom*dotom - yp*cosi*cosom*dotom // dX / dOMEGA
706 + yp*sini*sinom*doti; // dX / di
707
708 vv[1] = sinom *dotx + cosi*cosom *doty
709 + xp*cosom*dotom - yp*cosi*sinom*dotom
710 - yp*sini*cosom*doti;
711
712 vv[2] = sini *doty + yp*cosi *doti;
713
714 // Relativistic Correction
715 // -----------------------
716 // xc(4) -= 4.442807633e-10 * _e * sqrt(a0) *sin(E);
717 xc[3] -= 2.0 * (xc[0]*vv[0] + xc[1]*vv[1] + xc[2]*vv[2]) / t_CST::c / t_CST::c;
718}
719
720// build up RTCM3 for Galileo
721////////////////////////////////////////////////////////////////////////////
722int t_ephGal::RTCM3(unsigned char *buffer) {
723
724 return 0;
725}
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