#include <math.h>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstring>
#include <newmatio.h>
#include "ephemeris.h"
#include "bncutils.h"
#include "timeutils.h"
#include "bnctime.h"
using namespace std;
//
////////////////////////////////////////////////////////////////////////////
bool t_eph::isNewerThan(const t_eph* eph) const {
if (_GPSweek > eph->_GPSweek ||
(_GPSweek == eph->_GPSweek && _GPSweeks > eph->_GPSweeks)) {
return true;
}
else {
return false;
}
}
// Set GPS Satellite Position
////////////////////////////////////////////////////////////////////////////
void t_ephGPS::set(const gpsephemeris* ee) {
ostringstream prn;
prn << 'G' << setfill('0') << setw(2) << ee->satellite;
_prn = prn.str();
// TODO: check if following two lines are correct
_GPSweek = ee->GPSweek;
_GPSweeks = ee->TOE;
_TOW = ee->TOW;
_TOC = ee->TOC;
_TOE = ee->TOE;
_IODE = ee->IODE;
_IODC = ee->IODC;
_clock_bias = ee->clock_bias ;
_clock_drift = ee->clock_drift ;
_clock_driftrate = ee->clock_driftrate;
_Crs = ee->Crs;
_Delta_n = ee->Delta_n;
_M0 = ee->M0;
_Cuc = ee->Cuc;
_e = ee->e;
_Cus = ee->Cus;
_sqrt_A = ee->sqrt_A;
_Cic = ee->Cic;
_OMEGA0 = ee->OMEGA0;
_Cis = ee->Cis;
_i0 = ee->i0;
_Crc = ee->Crc;
_omega = ee->omega;
_OMEGADOT = ee->OMEGADOT;
_IDOT = ee->IDOT;
_TGD = ee->TGD;
}
// Compute GPS Satellite Position (virtual)
////////////////////////////////////////////////////////////////////////////
void t_ephGPS::position(int GPSweek, double GPSweeks,
double* xc,
double* vv) const {
static const double secPerWeek = 7 * 86400.0;
static const double omegaEarth = 7292115.1467e-11;
static const double gmWGS = 398.6005e12;
memset(xc, 0, 4*sizeof(double));
memset(vv, 0, 3*sizeof(double));
double a0 = _sqrt_A * _sqrt_A;
if (a0 == 0) {
return;
}
double n0 = sqrt(gmWGS/(a0*a0*a0));
double tk = GPSweeks - _TOE;
if (GPSweek != _GPSweek) {
tk += (GPSweek - _GPSweek) * secPerWeek;
}
double n = n0 + _Delta_n;
double M = _M0 + n*tk;
double E = M;
double E_last;
do {
E_last = E;
E = M + _e*sin(E);
} while ( fabs(E-E_last)*a0 > 0.001 );
double v = 2.0*atan( sqrt( (1.0 + _e)/(1.0 - _e) )*tan( E/2 ) );
double u0 = v + _omega;
double sin2u0 = sin(2*u0);
double cos2u0 = cos(2*u0);
double r = a0*(1 - _e*cos(E)) + _Crc*cos2u0 + _Crs*sin2u0;
double i = _i0 + _IDOT*tk + _Cic*cos2u0 + _Cis*sin2u0;
double u = u0 + _Cuc*cos2u0 + _Cus*sin2u0;
double xp = r*cos(u);
double yp = r*sin(u);
double OM = _OMEGA0 + (_OMEGADOT - omegaEarth)*tk -
omegaEarth*_TOE;
double sinom = sin(OM);
double cosom = cos(OM);
double sini = sin(i);
double cosi = cos(i);
xc[0] = xp*cosom - yp*cosi*sinom;
xc[1] = xp*sinom + yp*cosi*cosom;
xc[2] = yp*sini;
double tc = GPSweeks - _TOC;
if (GPSweek != _GPSweek) {
tc += (GPSweek - _GPSweek) * secPerWeek;
}
xc[3] = _clock_bias + _clock_drift*tc + _clock_driftrate*tc*tc;
// Velocity
// --------
double tanv2 = tan(v/2);
double dEdM = 1 / (1 - _e*cos(E));
double dotv = sqrt((1.0 + _e)/(1.0 - _e)) / cos(E/2)/cos(E/2) / (1 + tanv2*tanv2)
* dEdM * n;
double dotu = dotv + (-_Cuc*sin2u0 + _Cus*cos2u0)*2*dotv;
double dotom = _OMEGADOT - omegaEarth;
double doti = _IDOT + (-_Cic*sin2u0 + _Cis*cos2u0)*2*dotv;
double dotr = a0 * _e*sin(E) * dEdM * n
+ (-_Crc*sin2u0 + _Crs*cos2u0)*2*dotv;
double dotx = dotr*cos(u) - r*sin(u)*dotu;
double doty = dotr*sin(u) + r*cos(u)*dotu;
vv[0] = cosom *dotx - cosi*sinom *doty // dX / dr
- xp*sinom*dotom - yp*cosi*cosom*dotom // dX / dOMEGA
+ yp*sini*sinom*doti; // dX / di
vv[1] = sinom *dotx + cosi*cosom *doty
+ xp*cosom*dotom - yp*cosi*sinom*dotom
- yp*sini*cosom*doti;
vv[2] = sini *doty + yp*cosi *doti;
// Relativistic Correction
// -----------------------
// xc(4) -= 4.442807633e-10 * _e * sqrt(a0) *sin(E);
xc[3] -= 2.0 * (xc[0]*vv[0] + xc[1]*vv[1] + xc[2]*vv[2]) / t_CST::c / t_CST::c;
}
// Derivative of the state vector using a simple force model (static)
////////////////////////////////////////////////////////////////////////////
ColumnVector t_ephGlo::glo_deriv(double /* tt */, const ColumnVector& xv,
double* acc) {
// State vector components
// -----------------------
ColumnVector rr = xv.rows(1,3);
ColumnVector vv = xv.rows(4,6);
// Acceleration
// ------------
static const double GM = 398.60044e12;
static const double AE = 6378136.0;
static const double OMEGA = 7292115.e-11;
static const double C20 = -1082.6257e-6;
double rho = rr.norm_Frobenius();
double t1 = -GM/(rho*rho*rho);
double t2 = 3.0/2.0 * C20 * (GM*AE*AE) / (rho*rho*rho*rho*rho);
double t3 = OMEGA * OMEGA;
double t4 = 2.0 * OMEGA;
double z2 = rr(3) * rr(3);
// Vector of derivatives
// ---------------------
ColumnVector va(6);
va(1) = vv(1);
va(2) = vv(2);
va(3) = vv(3);
va(4) = (t1 + t2*(1.0-5.0*z2/(rho*rho)) + t3) * rr(1) + t4*vv(2) + acc[0];
va(5) = (t1 + t2*(1.0-5.0*z2/(rho*rho)) + t3) * rr(2) - t4*vv(1) + acc[1];
va(6) = (t1 + t2*(3.0-5.0*z2/(rho*rho)) ) * rr(3) + acc[2];
return va;
}
// Compute Glonass Satellite Position (virtual)
////////////////////////////////////////////////////////////////////////////
void t_ephGlo::position(int GPSweek, double GPSweeks,
double* xc, double* vv) const {
static const double secPerWeek = 7 * 86400.0;
static const double nominalStep = 10.0;
memset(xc, 0, 4*sizeof(double));
memset(vv, 0, 3*sizeof(double));
double dtPos = GPSweeks - _tt;
if (GPSweek != _GPSweek) {
dtPos += (GPSweek - _GPSweek) * secPerWeek;
}
int nSteps = int(fabs(dtPos) / nominalStep) + 1;
double step = dtPos / nSteps;
double acc[3];
acc[0] = _x_acceleration * 1.e3;
acc[1] = _y_acceleration * 1.e3;
acc[2] = _z_acceleration * 1.e3;
for (int ii = 1; ii <= nSteps; ii++) {
_xv = rungeKutta4(_tt, _xv, step, acc, glo_deriv);
_tt += step;
}
// Position and Velocity
// ---------------------
xc[0] = _xv(1);
xc[1] = _xv(2);
xc[2] = _xv(3);
vv[0] = _xv(4);
vv[1] = _xv(5);
vv[2] = _xv(6);
// Clock Correction
// ----------------
double dtClk = GPSweeks - _GPSweeks;
if (GPSweek != _GPSweek) {
dtClk += (GPSweek - _GPSweek) * secPerWeek;
}
xc[3] = -_tau + _gamma * dtClk;
}
// IOD of Glonass Ephemeris (virtual)
////////////////////////////////////////////////////////////////////////////
int t_ephGlo::IOD() const {
bool old = false;
if (old) { // 5 LSBs of iod are equal to 5 LSBs of tb
unsigned int tb = int(fmod(_GPSweeks,86400.0)); //sec of day
const int shift = sizeof(tb) * 8 - 5;
unsigned int iod = tb << shift;
return (iod >> shift);
}
else {
bncTime tGPS(_GPSweek, _GPSweeks);
int hlpWeek = _GPSweek;
int hlpSec = int(_GPSweeks);
int hlpMsec = int(_GPSweeks * 1000);
updatetime(&hlpWeek, &hlpSec, hlpMsec, 0);
bncTime tHlp(hlpWeek, hlpSec);
double diffSec = tGPS - tHlp;
bncTime tMoscow = tGPS + diffSec;
return int(tMoscow.daysec() / 900);
}
}
// Set Glonass Ephemeris
////////////////////////////////////////////////////////////////////////////
void t_ephGlo::set(const glonassephemeris* ee) {
ostringstream prn;
prn << 'R' << setfill('0') << setw(2) << ee->almanac_number;
_prn = prn.str();
int ww = ee->GPSWeek;
int tow = ee->GPSTOW;
updatetime(&ww, &tow, ee->tb*1000, 0); // Moscow -> GPS
_GPSweek = ww;
_GPSweeks = tow;
_E = ee->E;
_tau = ee->tau;
_gamma = ee->gamma;
_x_pos = ee->x_pos;
_x_velocity = ee->x_velocity;
_x_acceleration = ee->x_acceleration;
_y_pos = ee->y_pos;
_y_velocity = ee->y_velocity;
_y_acceleration = ee->y_acceleration;
_z_pos = ee->z_pos;
_z_velocity = ee->z_velocity;
_z_acceleration = ee->z_acceleration;
_health = 0;
_frequency_number = ee->frequency_number;
_tki = ee->tk-3*60*60; if (_tki < 0) _tki += 86400;
// Initialize status vector
// ------------------------
_tt = _GPSweeks;
_xv(1) = _x_pos * 1.e3;
_xv(2) = _y_pos * 1.e3;
_xv(3) = _z_pos * 1.e3;
_xv(4) = _x_velocity * 1.e3;
_xv(5) = _y_velocity * 1.e3;
_xv(6) = _z_velocity * 1.e3;
}