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Fix in rx time correction and adding the missing code phase to the observables. More test required

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This commit is contained in:
Javier Arribas 2018-05-17 18:10:48 +02:00
parent eeb2893f9c
commit 2b7663e70c
3 changed files with 38 additions and 10 deletions
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10
src/algorithms/PVT/gnuradio_blocks/rtklib_pvt_cc.cc
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@ -600,6 +600,13 @@ int rtklib_pvt_cc::work(int noutput_items, gr_vector_const_void_star& input_item
// ############ 2 COMPUTE THE PVT ################################
if (gnss_observables_map.size() > 0)
{
// correct the observable to account for the receiver clock offset
//observables fix
//std::cout << TEXT_RED << "(internal) accumulated RX clock offset: " << d_ls_pvt->get_time_offset_s() << "[s]" << TEXT_RESET << std::endl;
for (std::map<int, Gnss_Synchro>::iterator it = gnss_observables_map.begin(); it != gnss_observables_map.end(); ++it)
{
it->second.Pseudorange_m = it->second.Pseudorange_m - d_ls_pvt->get_time_offset_s() * GPS_C_m_s;
}
double current_RX_time = gnss_observables_map.begin()->second.RX_time;
if (std::fabs(current_RX_time - d_rx_time) * 1000.0 >= static_cast<double>(d_output_rate_ms))
@ -665,7 +672,6 @@ int rtklib_pvt_cc::work(int noutput_items, gr_vector_const_void_star& input_item
}
// correct the observable to account for the receiver clock offset
for (std::map<int, Gnss_Synchro>::iterator it = gnss_observables_map.begin(); it != gnss_observables_map.end(); ++it)
{
it->second.Pseudorange_m = it->second.Pseudorange_m - d_ls_pvt->get_time_offset_s() * GPS_C_m_s;
@ -2075,7 +2081,7 @@ int rtklib_pvt_cc::work(int noutput_items, gr_vector_const_void_star& input_item
std::cout << TEXT_BOLD_GREEN << "Position at " << boost::posix_time::to_simple_string(d_ls_pvt->get_position_UTC_time())
<< " UTC using " << d_ls_pvt->get_num_valid_observations() << " observations is Lat = " << d_ls_pvt->get_latitude() << " [deg], Long = " << d_ls_pvt->get_longitude()
<< " [deg], Height= " << d_ls_pvt->get_height() << " [m]" << TEXT_RESET << std::endl;
std::cout << TEXT_RED << "accumulated RX clock offset: " << d_ls_pvt->get_time_offset_s() << "[s]" << TEXT_RESET << std::endl;
LOG(INFO) << "Position at " << boost::posix_time::to_simple_string(d_ls_pvt->get_position_UTC_time())
<< " UTC using " << d_ls_pvt->get_num_valid_observations() << " observations is Lat = " << d_ls_pvt->get_latitude() << " [deg], Long = " << d_ls_pvt->get_longitude()
<< " [deg], Height= " << d_ls_pvt->get_height() << " [m]";

25
src/algorithms/PVT/libs/rtklib_solver.cc
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@ -481,13 +481,26 @@ bool rtklib_solver::get_PVT(const std::map<int, Gnss_Synchro>& gnss_observables_
this->set_valid_position(true);
arma::vec rx_position_and_time(4);
rx_position_and_time(0) = pvt_sol.rr[0];
rx_position_and_time(1) = pvt_sol.rr[1];
rx_position_and_time(2) = pvt_sol.rr[2];
rx_position_and_time(3) = pvt_sol.dtr[0];
rx_position_and_time(0) = pvt_sol.rr[0]; //[m]
rx_position_and_time(1) = pvt_sol.rr[1]; //[m]
rx_position_and_time(2) = pvt_sol.rr[2]; //[m]
//todo: fix this ambiguity in the RTKLIB units in receiver clock offset!
if (rtk_.opt.mode == PMODE_SINGLE)
{
rx_position_and_time(3) = pvt_sol.dtr[0]; //if the RTKLIB solver is set to SINGLE, the dtr is already expressed in [s]
}
else
{
rx_position_and_time(3) = pvt_sol.dtr[0] / GPS_C_m_s; // the receiver clock offset is expressed in [meters]
}
//[s]
this->set_rx_pos(rx_position_and_time.rows(0, 2)); // save ECEF position for the next iteration
double offset_s = this->get_time_offset_s();
this->set_time_offset_s(offset_s + (rx_position_and_time(3) / GPS_C_m_s)); // accumulate the rx time error for the next iteration [meters]->[seconds]
//observable fix:
//double offset_s = this->get_time_offset_s();
//this->set_time_offset_s(offset_s + (rx_position_and_time(3) / GPS_C_m_s)); // accumulate the rx time error for the next iteration [meters]->[seconds]
this->set_time_offset_s(rx_position_and_time(3));
DLOG(INFO) << "RTKLIB Position at TOW=" << Rx_time << " in ECEF (X,Y,Z,t[meters]) = " << rx_position_and_time;
boost::posix_time::ptime p_time;

13
src/algorithms/observables/gnuradio_blocks/hybrid_observables_cc.cc
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@ -316,6 +316,10 @@ bool hybrid_observables_cc::interpolate_data(Gnss_Synchro &out, const unsigned i
// CARRIER DOPPLER INTERPOLATION
out.Carrier_Doppler_hz = d_gnss_synchro_history->at(ch, 0).Carrier_Doppler_hz + (d_gnss_synchro_history->at(ch, 1).Carrier_Doppler_hz - d_gnss_synchro_history->at(ch, 0).Carrier_Doppler_hz) * (ti - d_gnss_synchro_history->at(ch, 0).RX_time) / (d_gnss_synchro_history->at(ch, 1).RX_time - d_gnss_synchro_history->at(ch, 0).RX_time);
// todo: CODE PHASE IS MISSING!
// todo: convert to seconds, considering fs per channel
out.Code_phase_samples = d_gnss_synchro_history->at(ch, 0).Code_phase_samples + (d_gnss_synchro_history->at(ch, 1).Code_phase_samples - d_gnss_synchro_history->at(ch, 0).Code_phase_samples) * (ti - d_gnss_synchro_history->at(ch, 0).RX_time) / (d_gnss_synchro_history->at(ch, 1).RX_time - d_gnss_synchro_history->at(ch, 0).RX_time);
// TOW INTERPOLATION
out.TOW_at_current_symbol_s = d_gnss_synchro_history->at(ch, 0).TOW_at_current_symbol_s + (d_gnss_synchro_history->at(ch, 1).TOW_at_current_symbol_s - d_gnss_synchro_history->at(ch, 0).TOW_at_current_symbol_s) * (ti - d_gnss_synchro_history->at(ch, 0).RX_time) / (d_gnss_synchro_history->at(ch, 1).RX_time - d_gnss_synchro_history->at(ch, 0).RX_time);
@ -434,17 +438,22 @@ void hybrid_observables_cc::correct_TOW_and_compute_prange(std::vector<Gnss_Sync
///////////////////////////////////////////////////////////
double TOW_ref = std::numeric_limits<double>::lowest();
double Code_phase_ref_s = 0.0;
for (it = data.begin(); it != data.end(); it++)
{
if (it->TOW_at_current_symbol_s > TOW_ref)
{
TOW_ref = it->TOW_at_current_symbol_s;
Code_phase_ref_s = it->Code_phase_samples / static_cast<double>(it->fs);
}
}
for (it = data.begin(); it != data.end(); it++)
{
double traveltime_s = TOW_ref - it->TOW_at_current_symbol_s + GPS_STARTOFFSET_ms / 1000.0;
it->RX_time = TOW_ref + GPS_STARTOFFSET_ms / 1000.0;
//double traveltime_s = TOW_ref - it->TOW_at_current_symbol_s + GPS_STARTOFFSET_ms / 1000.0;
double traveltime_s = TOW_ref - it->TOW_at_current_symbol_s + Code_phase_ref_s - it->Code_phase_samples / static_cast<double>(it->fs) + GPS_STARTOFFSET_ms / 1000.0;
//it->RX_time = TOW_ref + GPS_STARTOFFSET_ms / 1000.0;
it->RX_time = TOW_ref + Code_phase_ref_s + GPS_STARTOFFSET_ms / 1000.0;
it->Pseudorange_m = traveltime_s * SPEED_OF_LIGHT;
}
}