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Bug fix in LS PVT solver in troposphere corrections causing erratic position fixes in high altitude GNSS receiver operations (>15 km)

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This commit is contained in:
Javier Arribas 2017-01-11 17:31:22 +01:00
parent 938db73b43
commit 235aa77357
4 changed files with 12 additions and 27 deletions
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6
src/algorithms/PVT/libs/galileo_e1_ls_pvt.cc
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@ -178,12 +178,6 @@ bool galileo_e1_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map
cart2geo(static_cast<double>(mypos(0)), static_cast<double>(mypos(1)), static_cast<double>(mypos(2)), 4);
d_rx_dt_m = mypos(3)/GALILEO_C_m_s; // Convert RX time offset from meters to seconds
//ToDo: Find an Observables/PVT random bug with some satellite configurations that gives an erratic PVT solution (i.e. height>50 km)
if (d_height_m > 50000)
{
b_valid_position = false;
return false;
}
DLOG(INFO) << "Galileo Position at " << boost::posix_time::to_simple_string(p_time)
<< " is Lat = " << d_latitude_d << " [deg], Long = " << d_longitude_d
<< " [deg], Height= " << d_height_m << " [m]" << " RX time offset= " << d_rx_dt_m << " [s]";

9
src/algorithms/PVT/libs/gps_l1_ca_ls_pvt.cc
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@ -174,13 +174,6 @@ bool gps_l1_ca_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map,
d_rx_dt_m = mypos(3)/GPS_C_m_s; // Convert RX time offset from meters to seconds
//ToDo: Find an Observables/PVT random bug with some satellite configurations that gives an erratic PVT solution (i.e. height>50 km)
if (d_height_m > 50000)
{
DLOG(INFO)<<"LS: bad height\n";
b_valid_position = false;
return false;
}
// Compute UTC time and print PVT solution
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 + secondsperweek * static_cast<double>(GPS_week));
@ -188,7 +181,7 @@ bool gps_l1_ca_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map,
boost::posix_time::ptime p_time(boost::gregorian::date(1999, 8, 22), t);
d_position_UTC_time = p_time;
LOG(INFO) << "(new)Position at " << boost::posix_time::to_simple_string(p_time)
DLOG(INFO) << "Position at " << boost::posix_time::to_simple_string(p_time)
<< " is Lat = " << d_latitude_d << " [deg], Long = " << d_longitude_d
<< " [deg], Height= " << d_height_m << " [m]" << " RX time offset= " << d_rx_dt_m << " [s]";

11
src/algorithms/PVT/libs/hybrid_ls_pvt.cc
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@ -297,17 +297,8 @@ bool hybrid_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_observables_map, dou
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);
//ToDo: Find an Observables/PVT random bug with some satellite configurations that gives an erratic PVT solution (i.e. height>50 km)
if (d_height_m > 50000)
{
b_valid_position = false;
LOG(INFO) << "Hybrid Position at " << boost::posix_time::to_simple_string(p_time)
<< " is Lat = " << d_latitude_d << " [deg], Long = " << d_longitude_d
<< " [deg], Height= " << d_height_m << " [m]" << " RX time offset= " << mypos(3) << " [s]";
return false;
}
LOG(INFO) << "Hybrid Position at " << boost::posix_time::to_simple_string(p_time)
DLOG(INFO) << "Hybrid Position at " << boost::posix_time::to_simple_string(p_time)
<< " is Lat = " << d_latitude_d << " [deg], Long = " << d_longitude_d
<< " [deg], Height= " << d_height_m << " [m]" << " RX time offset= " << d_rx_dt_m << " [s]";

13
src/algorithms/PVT/libs/ls_pvt.cc
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@ -116,10 +116,17 @@ arma::vec Ls_Pvt::leastSquarePos(const arma::mat & satpos, const arma::vec & obs
{
//--- Find receiver's height
Ls_Pvt::togeod(&dphi, &dlambda, &h, 6378137.0, 298.257223563, pos(0), pos(1), pos(2));
// Add troposphere correction if the receiver is below the troposphere
if (h > 15000)
{
//receiver is above the troposphere
trop = 0.0;
}else{
//--- Find delay due to troposphere (in meters)
Ls_Pvt::tropo(&trop, sin(d_visible_satellites_El[i] * GPS_PI / 180.0), h / 1000.0, 1013.0, 293.0, 50.0, 0.0, 0.0, 0.0);
if(trop > 5.0 ) trop = 0.0; //check for erratic values
}
//--- Find delay due to troposphere (in meters)
Ls_Pvt::tropo(&trop, sin(d_visible_satellites_El[i] * GPS_PI / 180.0), h / 1000.0, 1013.0, 293.0, 50.0, 0.0, 0.0, 0.0);
if(trop > 50.0 ) trop = 0.0;
}
}
//--- Apply the corrections ----------------------------------------