mirror of https://github.com/gnss-sdr/gnss-sdr
245 lines
11 KiB
C++
245 lines
11 KiB
C++
/*!
|
|
* \file gps_l1_ca_ls_pvt.cc
|
|
* \brief Implementation of a Least Squares Position, Velocity, and Time
|
|
* (PVT) solver, based on K.Borre's Matlab receiver.
|
|
* \author Javier Arribas, 2011. jarribas(at)cttc.es
|
|
* -------------------------------------------------------------------------
|
|
*
|
|
* Copyright (C) 2010-2015 (see AUTHORS file for a list of contributors)
|
|
*
|
|
* GNSS-SDR is a software defined Global Navigation
|
|
* Satellite Systems receiver
|
|
*
|
|
* This file is part of GNSS-SDR.
|
|
*
|
|
* GNSS-SDR is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* GNSS-SDR is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
* -------------------------------------------------------------------------
|
|
*/
|
|
|
|
|
|
#include "gps_l1_ca_ls_pvt.h"
|
|
#include <gflags/gflags.h>
|
|
#include <glog/logging.h>
|
|
|
|
|
|
using google::LogMessage;
|
|
|
|
|
|
gps_l1_ca_ls_pvt::gps_l1_ca_ls_pvt(int nchannels, std::string dump_filename, bool flag_dump_to_file) : Ls_Pvt()
|
|
{
|
|
// init empty ephemeris for all the available GNSS channels
|
|
d_nchannels = nchannels;
|
|
d_ephemeris = new Gps_Navigation_Message[nchannels];
|
|
d_dump_filename = dump_filename;
|
|
d_flag_dump_enabled = flag_dump_to_file;
|
|
d_flag_averaging = false;
|
|
d_GPS_current_time = 0;
|
|
|
|
// ############# ENABLE DATA FILE LOG #################
|
|
if (d_flag_dump_enabled == true)
|
|
{
|
|
if (d_dump_file.is_open() == false)
|
|
{
|
|
try
|
|
{
|
|
d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit);
|
|
d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
|
|
LOG(INFO) << "PVT lib dump enabled Log file: " << d_dump_filename.c_str();
|
|
}
|
|
catch (std::ifstream::failure e)
|
|
{
|
|
LOG(WARNING) << "Exception opening PVT lib dump file " << e.what();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
|
|
gps_l1_ca_ls_pvt::~gps_l1_ca_ls_pvt()
|
|
{
|
|
d_dump_file.close();
|
|
delete[] d_ephemeris;
|
|
}
|
|
|
|
|
|
|
|
bool gps_l1_ca_ls_pvt::get_PVT(std::map<int,Gnss_Synchro> gnss_pseudoranges_map, double GPS_current_time, bool flag_averaging)
|
|
{
|
|
std::map<int,Gnss_Synchro>::iterator gnss_pseudoranges_iter;
|
|
std::map<int,Gps_Ephemeris>::iterator gps_ephemeris_iter;
|
|
int valid_pseudoranges = gnss_pseudoranges_map.size();
|
|
|
|
arma::mat W = arma::eye(valid_pseudoranges, valid_pseudoranges); //channels weights matrix
|
|
arma::vec obs = arma::zeros(valid_pseudoranges); // pseudoranges observation vector
|
|
arma::mat satpos = arma::zeros(3, valid_pseudoranges); //satellite positions matrix
|
|
|
|
int GPS_week = 0;
|
|
double utc = 0;
|
|
double TX_time_corrected_s;
|
|
double SV_clock_bias_s = 0;
|
|
|
|
d_flag_averaging = flag_averaging;
|
|
|
|
// ********************************************************************************
|
|
// ****** PREPARE THE LEAST SQUARES DATA (SV POSITIONS MATRIX AND OBS VECTORS) ****
|
|
// ********************************************************************************
|
|
int valid_obs = 0; //valid observations counter
|
|
int obs_counter = 0;
|
|
for(gnss_pseudoranges_iter = gnss_pseudoranges_map.begin();
|
|
gnss_pseudoranges_iter != gnss_pseudoranges_map.end();
|
|
gnss_pseudoranges_iter++)
|
|
{
|
|
// 1- find the ephemeris for the current SV observation. The SV PRN ID is the map key
|
|
gps_ephemeris_iter = gps_ephemeris_map.find(gnss_pseudoranges_iter->first);
|
|
if (gps_ephemeris_iter != gps_ephemeris_map.end())
|
|
{
|
|
/*!
|
|
* \todo Place here the satellite CN0 (power level, or weight factor)
|
|
*/
|
|
W(obs_counter, obs_counter) = 1;
|
|
|
|
// COMMON RX TIME PVT ALGORITHM MODIFICATION (Like RINEX files)
|
|
// first estimate of transmit time
|
|
double Rx_time = GPS_current_time;
|
|
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, including relativistic effect
|
|
SV_clock_bias_s = gps_ephemeris_iter->second.sv_clock_drift(Tx_time); //- gps_ephemeris_iter->second.d_TGD;
|
|
|
|
// 3- compute the current ECEF position for this SV using corrected TX time
|
|
TX_time_corrected_s = Tx_time - SV_clock_bias_s;
|
|
gps_ephemeris_iter->second.satellitePosition(TX_time_corrected_s);
|
|
|
|
satpos(0, obs_counter) = gps_ephemeris_iter->second.d_satpos_X;
|
|
satpos(1, obs_counter) = gps_ephemeris_iter->second.d_satpos_Y;
|
|
satpos(2, obs_counter) = gps_ephemeris_iter->second.d_satpos_Z;
|
|
|
|
// 4- fill the observations vector with the corrected pseudoranges
|
|
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_CN0_dB[valid_obs] = gnss_pseudoranges_iter->second.CN0_dB_hz;
|
|
valid_obs++;
|
|
|
|
// SV ECEF DEBUG OUTPUT
|
|
DLOG(INFO) << "(new)ECEF satellite SV ID=" << gps_ephemeris_iter->second.i_satellite_PRN
|
|
<< " X=" << gps_ephemeris_iter->second.d_satpos_X
|
|
<< " [m] Y=" << gps_ephemeris_iter->second.d_satpos_Y
|
|
<< " [m] Z=" << gps_ephemeris_iter->second.d_satpos_Z
|
|
<< " [m] PR_obs=" << obs(obs_counter) << " [m]";
|
|
|
|
// compute the UTC time for this SV (just to print the associated UTC timestamp)
|
|
GPS_week = gps_ephemeris_iter->second.i_GPS_week;
|
|
utc = gps_utc_model.utc_time(TX_time_corrected_s, GPS_week);
|
|
}
|
|
else // the ephemeris are not available for this SV
|
|
{
|
|
// no valid pseudorange for the current SV
|
|
W(obs_counter, obs_counter) = 0; // SV de-activated
|
|
obs(obs_counter) = 1; // to avoid algorithm problems (divide by zero)
|
|
DLOG(INFO) << "No ephemeris data for SV " << gnss_pseudoranges_iter->first;
|
|
}
|
|
obs_counter++;
|
|
}
|
|
|
|
// ********************************************************************************
|
|
// ****** SOLVE LEAST SQUARES******************************************************
|
|
// ********************************************************************************
|
|
d_valid_observations = valid_obs;
|
|
LOG(INFO) << "(new)PVT: valid observations=" << valid_obs;
|
|
|
|
if (valid_obs >= 4)
|
|
{
|
|
arma::vec mypos;
|
|
DLOG(INFO) << "satpos=" << satpos;
|
|
DLOG(INFO) << "obs=" << obs;
|
|
DLOG(INFO) << "W=" << W;
|
|
|
|
mypos = gps_l1_ca_ls_pvt::leastSquarePos(satpos, obs, W);
|
|
|
|
DLOG(INFO) << "(new)Position at TOW=" << GPS_current_time << " in ECEF (X,Y,Z) = " << mypos;
|
|
|
|
gps_l1_ca_ls_pvt::cart2geo(mypos(0), mypos(1), 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;
|
|
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));
|
|
// 22 August 1999 last GPS time roll over
|
|
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)
|
|
<< " is Lat = " << d_latitude_d << " [deg], Long = " << d_longitude_d
|
|
<< " [deg], Height= " << d_height_m << " [m]";
|
|
|
|
// ###### Compute DOPs ########
|
|
gps_l1_ca_ls_pvt::compute_DOP();
|
|
|
|
// ######## LOG FILE #########
|
|
if(d_flag_dump_enabled == true)
|
|
{
|
|
// MULTIPLEXED FILE RECORDING - Record results to file
|
|
try
|
|
{
|
|
double tmp_double;
|
|
// PVT GPS time
|
|
tmp_double = GPS_current_time;
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// ECEF User Position East [m]
|
|
tmp_double = mypos(0);
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// ECEF User Position North [m]
|
|
tmp_double = mypos(1);
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// ECEF User Position Up [m]
|
|
tmp_double = mypos(2);
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// User clock offset [s]
|
|
tmp_double = mypos(3);
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// GEO user position Latitude [deg]
|
|
tmp_double = d_latitude_d;
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// GEO user position Longitude [deg]
|
|
tmp_double = d_longitude_d;
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
// GEO user position Height [m]
|
|
tmp_double = d_height_m;
|
|
d_dump_file.write((char*)&tmp_double, sizeof(double));
|
|
}
|
|
catch (std::ifstream::failure e)
|
|
{
|
|
LOG(WARNING) << "Exception writing PVT LS dump file " << e.what();
|
|
}
|
|
}
|
|
|
|
// MOVING AVERAGE PVT
|
|
gps_l1_ca_ls_pvt::pos_averaging(flag_averaging);
|
|
}
|
|
else
|
|
{
|
|
b_valid_position = false;
|
|
}
|
|
return b_valid_position;
|
|
}
|
|
|
|
|