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Fix computation of time in the hybrid Galileo/GPS solution

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This commit is contained in:
Carles Fernandez 2016-05-10 21:19:09 +02:00
parent 3bd4547b57
commit fc7d3118c5
1 changed files with 14 additions and 20 deletions
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34
src/algorithms/PVT/libs/hybrid_ls_pvt.cc
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@ -69,8 +69,6 @@ hybrid_ls_pvt::hybrid_ls_pvt(int nchannels, std::string dump_filename, bool flag
} }
hybrid_ls_pvt::~hybrid_ls_pvt() hybrid_ls_pvt::~hybrid_ls_pvt()
{ {
d_dump_file.close(); d_dump_file.close();
@ -79,10 +77,6 @@ hybrid_ls_pvt::~hybrid_ls_pvt()
} }
bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, double hybrid_current_time, bool flag_averaging) bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, double hybrid_current_time, bool flag_averaging)
{ {
std::map<int,Gnss_Synchro>::iterator gnss_pseudoranges_iter; std::map<int,Gnss_Synchro>::iterator gnss_pseudoranges_iter;
@ -115,10 +109,8 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
gnss_pseudoranges_iter != gnss_pseudoranges_map.end(); gnss_pseudoranges_iter != gnss_pseudoranges_map.end();
gnss_pseudoranges_iter++) gnss_pseudoranges_iter++)
{ {
if(gnss_pseudoranges_iter->second.System == 'E')
if (gnss_pseudoranges_iter->second.System == 'E')
{ {
//std::cout << "Satellite System: " << gnss_pseudoranges_iter->second.System <<std::endl;
// 1 Gal - find the ephemeris for the current GALILEO SV observation. The SV PRN ID is the map key // 1 Gal - find the ephemeris for the current GALILEO SV observation. The SV PRN ID is the map key
galileo_ephemeris_iter = galileo_ephemeris_map.find(gnss_pseudoranges_iter->second.PRN); galileo_ephemeris_iter = galileo_ephemeris_map.find(gnss_pseudoranges_iter->second.PRN);
if (galileo_ephemeris_iter != galileo_ephemeris_map.end()) if (galileo_ephemeris_iter != galileo_ephemeris_map.end())
@ -130,7 +122,7 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
// COMMON RX TIME PVT ALGORITHM // COMMON RX TIME PVT ALGORITHM
double Rx_time = hybrid_current_time; double Rx_time = hybrid_current_time;
double Tx_time = Rx_time - gnss_pseudoranges_iter->second.Pseudorange_m/GALILEO_C_m_s; double Tx_time = Rx_time - gnss_pseudoranges_iter->second.Pseudorange_m / GALILEO_C_m_s;
// 2- compute the clock drift using the clock model (broadcast) for this SV // 2- compute the clock drift using the clock model (broadcast) for this SV
SV_clock_bias_s = galileo_ephemeris_iter->second.sv_clock_drift(Tx_time); SV_clock_bias_s = galileo_ephemeris_iter->second.sv_clock_drift(Tx_time);
@ -144,7 +136,7 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
satpos(2,obs_counter) = galileo_ephemeris_iter->second.d_satpos_Z; satpos(2,obs_counter) = galileo_ephemeris_iter->second.d_satpos_Z;
// 5- fill the observations vector with the corrected pseudoranges // 5- fill the observations vector with the corrected pseudoranges
obs(obs_counter) = gnss_pseudoranges_iter->second.Pseudorange_m + SV_clock_bias_s*GALILEO_C_m_s; obs(obs_counter) = gnss_pseudoranges_iter->second.Pseudorange_m + SV_clock_bias_s * GALILEO_C_m_s;
d_visible_satellites_IDs[valid_obs] = galileo_ephemeris_iter->second.i_satellite_PRN; d_visible_satellites_IDs[valid_obs] = galileo_ephemeris_iter->second.i_satellite_PRN;
d_visible_satellites_CN0_dB[valid_obs] = gnss_pseudoranges_iter->second.CN0_dB_hz; d_visible_satellites_CN0_dB[valid_obs] = gnss_pseudoranges_iter->second.CN0_dB_hz;
valid_obs++; valid_obs++;
@ -170,7 +162,7 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
} }
} }
else if (gnss_pseudoranges_iter->second.System == 'G') else if(gnss_pseudoranges_iter->second.System == 'G')
{ {
//std::cout << "Satellite System: " << gnss_pseudoranges_iter->second.System <<std::endl; //std::cout << "Satellite System: " << gnss_pseudoranges_iter->second.System <<std::endl;
// 1 GPS - find the ephemeris for the current GPS SV observation. The SV PRN ID is the map key // 1 GPS - find the ephemeris for the current GPS SV observation. The SV PRN ID is the map key
@ -185,7 +177,7 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
// COMMON RX TIME PVT ALGORITHM MODIFICATION (Like RINEX files) // COMMON RX TIME PVT ALGORITHM MODIFICATION (Like RINEX files)
// first estimate of transmit time // first estimate of transmit time
double Rx_time = hybrid_current_time; double Rx_time = hybrid_current_time;
double Tx_time = Rx_time - gnss_pseudoranges_iter->second.Pseudorange_m/GPS_C_m_s; double Tx_time = Rx_time - gnss_pseudoranges_iter->second.Pseudorange_m / GPS_C_m_s;
// 2- compute the clock drift using the clock model (broadcast) for this SV // 2- compute the clock drift using the clock model (broadcast) for this SV
SV_clock_bias_s = gps_ephemeris_iter->second.sv_clock_drift(Tx_time); SV_clock_bias_s = gps_ephemeris_iter->second.sv_clock_drift(Tx_time);
@ -199,7 +191,7 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
satpos(2, obs_counter) = gps_ephemeris_iter->second.d_satpos_Z; satpos(2, obs_counter) = gps_ephemeris_iter->second.d_satpos_Z;
// 5- fill the observations vector with the corrected pseudorranges // 5- fill the observations vector with the corrected pseudorranges
obs(obs_counter) = gnss_pseudoranges_iter->second.Pseudorange_m + SV_clock_bias_s*GPS_C_m_s; obs(obs_counter) = gnss_pseudoranges_iter->second.Pseudorange_m + SV_clock_bias_s * GPS_C_m_s;
d_visible_satellites_IDs[valid_obs] = gps_ephemeris_iter->second.i_satellite_PRN; d_visible_satellites_IDs[valid_obs] = gps_ephemeris_iter->second.i_satellite_PRN;
d_visible_satellites_CN0_dB[valid_obs] = gnss_pseudoranges_iter->second.CN0_dB_hz; d_visible_satellites_CN0_dB[valid_obs] = gnss_pseudoranges_iter->second.CN0_dB_hz;
valid_obs++; valid_obs++;
@ -232,15 +224,16 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
d_valid_GAL_obs = valid_obs_GALILEO_counter; d_valid_GAL_obs = valid_obs_GALILEO_counter;
LOG(INFO) << "HYBRID PVT: valid observations=" << valid_obs; LOG(INFO) << "HYBRID PVT: valid observations=" << valid_obs;
if (valid_obs >= 4) if(valid_obs >= 4)
{ {
arma::vec mypos; arma::vec mypos;
DLOG(INFO) << "satpos=" << satpos; DLOG(INFO) << "satpos=" << satpos;
DLOG(INFO) << "obs="<< obs; DLOG(INFO) << "obs=" << obs;
DLOG(INFO) << "W=" << W; DLOG(INFO) << "W=" << W;
mypos = leastSquarePos(satpos, obs, W); mypos = leastSquarePos(satpos, obs, W);
d_rx_dt_m = mypos(3)/GPS_C_m_s; // Convert RX time offset from meters to seconds d_rx_dt_m = mypos(3)/GPS_C_m_s; // Convert RX time offset from meters to seconds
double secondsperweek = 604800.0;
// Compute GST and Gregorian time // Compute GST and Gregorian time
if( GST != 0.0) if( GST != 0.0)
{ {
@ -248,14 +241,15 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
} }
else else
{ {
utc = gps_utc_model.utc_time(TX_time_corrected_s, GPS_week); utc = gps_utc_model.utc_time(TX_time_corrected_s, GPS_week) + secondsperweek * static_cast<double>(GPS_week);
} }
// get time string Gregorian calendar // get time string Gregorian calendar
double secondsperweek = 604800.0; // number of seconds in one week (7*24*60*60) boost::posix_time::time_duration t = boost::posix_time::seconds(utc);
boost::posix_time::time_duration t = boost::posix_time::seconds(utc + secondsperweek * static_cast<double>(GPS_week));
// 22 August 1999 00:00 last Galileo start GST epoch (ICD sec 5.1.2) // 22 August 1999 00:00 last Galileo start GST epoch (ICD sec 5.1.2)
boost::posix_time::ptime p_time(boost::gregorian::date(1999, 8, 22), t); boost::posix_time::ptime p_time(boost::gregorian::date(1999, 8, 22), t);
d_position_UTC_time = p_time; d_position_UTC_time = p_time;
DLOG(INFO) << "HYBRID Position at TOW=" << hybrid_current_time << " in ECEF (X,Y,Z) = " << mypos; DLOG(INFO) << "HYBRID Position at TOW=" << hybrid_current_time << " in ECEF (X,Y,Z) = " << mypos;
cart2geo(static_cast<double>(mypos(0)), static_cast<double>(mypos(1)), static_cast<double>(mypos(2)), 4); cart2geo(static_cast<double>(mypos(0)), static_cast<double>(mypos(1)), static_cast<double>(mypos(2)), 4);
@ -310,7 +304,7 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, do
} }
catch (const std::ifstream::failure& e) catch (const std::ifstream::failure& e)
{ {
LOG(WARNING) << "Exception writing PVT LS dump file "<< e.what(); LOG(WARNING) << "Exception writing PVT LS dump file " << e.what();
} }
} }