mirror of https://github.com/gnss-sdr/gnss-sdr
272 lines
11 KiB
C++
272 lines
11 KiB
C++
/*!
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* \file gps_l5_telemetry_decoder_cc.cc
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* \brief Implementation of a NAV message demodulator block based on
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* Kay Borre book MATLAB-based GPS receiver
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* \author Antonio Ramos, 2017. antonio.ramos(at)cttc.es
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*
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* -------------------------------------------------------------------------
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*
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* Copyright (C) 2010-2017 (see AUTHORS file for a list of contributors)
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*
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* GNSS-SDR is a software defined Global Navigation
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* Satellite Systems receiver
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*
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* This file is part of GNSS-SDR.
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*
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* GNSS-SDR is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GNSS-SDR is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
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*
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* -------------------------------------------------------------------------
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*/
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#include <bitset>
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#include <iostream>
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#include <sstream>
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#include <gnuradio/io_signature.h>
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#include <glog/logging.h>
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#include <boost/lexical_cast.hpp>
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#include "gnss_synchro.h"
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#include "gps_l5_telemetry_decoder_cc.h"
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#include "gps_cnav_ephemeris.h"
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#include "gps_cnav_iono.h"
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using google::LogMessage;
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gps_l5_telemetry_decoder_cc_sptr
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gps_l5_make_telemetry_decoder_cc(const Gnss_Satellite & satellite, bool dump)
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{
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return gps_l5_telemetry_decoder_cc_sptr(new gps_l5_telemetry_decoder_cc(satellite, dump));
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}
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gps_l5_telemetry_decoder_cc::gps_l5_telemetry_decoder_cc(
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const Gnss_Satellite & satellite, bool dump) : gr::block("gps_l5_telemetry_decoder_cc",
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gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)),
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gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
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{
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// Telemetry Bit transition synchronization port out
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this->message_port_register_out(pmt::mp("preamble_timestamp_s"));
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// Ephemeris data port out
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this->message_port_register_out(pmt::mp("telemetry"));
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// initialize internal vars
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d_dump = dump;
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d_satellite = Gnss_Satellite(satellite.get_system(), satellite.get_PRN());
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DLOG(INFO) << "GPS L5 TELEMETRY PROCESSING: satellite " << d_satellite;
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d_channel = 0;
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d_flag_valid_word = false;
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d_TOW_at_current_symbol = 0.0;
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d_TOW_at_Preamble = 0.0;
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//initialize the CNAV frame decoder (libswiftcnav)
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cnav_msg_decoder_init(&d_cnav_decoder);
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for(int aux = 0; aux < GPS_L5_NH_CODE_LENGTH; aux++)
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{
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if(GPS_L5_NH_CODE[aux] == 0)
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{
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bits_NH[aux] = -1.0;
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}
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else
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{
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bits_NH[aux] = 1.0;
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}
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}
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sync_NH = false;
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new_sym = false;
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}
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gps_l5_telemetry_decoder_cc::~gps_l5_telemetry_decoder_cc()
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{
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if(d_dump_file.is_open() == true)
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{
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try
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{
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d_dump_file.close();
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}
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catch(const std::exception & ex)
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{
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LOG(WARNING) << "Exception in destructor closing the dump file " << ex.what();
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}
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}
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}
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int gps_l5_telemetry_decoder_cc::general_work (int noutput_items __attribute__((unused)), gr_vector_int &ninput_items __attribute__((unused)),
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gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
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{
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// get pointers on in- and output gnss-synchro objects
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Gnss_Synchro *out = reinterpret_cast<Gnss_Synchro *>(output_items[0]); // Get the output buffer pointer
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const Gnss_Synchro *in = reinterpret_cast<const Gnss_Synchro *>(input_items[0]); // Get the input buffer pointer
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// UPDATE GNSS SYNCHRO DATA
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Gnss_Synchro current_synchro_data; //structure to save the synchronization information and send the output object to the next block
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//1. Copy the current tracking output
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current_synchro_data = in[0];
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consume_each(1); //one by one
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sym_hist.push_back(in[0].Prompt_I);
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int corr_NH = 0;
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int symbol_value = 0;
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//Search correlation with Neuman-Hofman Code (see IS-GPS-705D)
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if(sym_hist.size() == GPS_L5_NH_CODE_LENGTH)
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{
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for(int i = 0; i < GPS_L5_NH_CODE_LENGTH; i++)
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{
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if((bits_NH[i] * sym_hist.at(i)) > 0.0) {corr_NH += 1;}
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else {corr_NH -= 1;}
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}
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if(abs(corr_NH) == GPS_L5_NH_CODE_LENGTH)
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{
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sync_NH = true;
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if(corr_NH > 0) {symbol_value = 1;}
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else {symbol_value = -1;}
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new_sym = true;
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sym_hist.clear();
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}
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else
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{
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sym_hist.pop_front();
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sync_NH = false;
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new_sym = false;
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}
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}
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bool flag_new_cnav_frame = false;
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cnav_msg_t msg;
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u32 delay = 0;
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//add the symbol to the decoder
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if(new_sym)
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{
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u8 symbol_clip = static_cast<u8>(symbol_value > 0) * 255;
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flag_new_cnav_frame = cnav_msg_decoder_add_symbol(&d_cnav_decoder, symbol_clip, &msg, &delay);
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new_sym = false;
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}
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//2. Add the telemetry decoder information
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//check if new CNAV frame is available
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if (flag_new_cnav_frame == true)
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{
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std::bitset<GPS_L5_CNAV_DATA_PAGE_BITS> raw_bits;
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//Expand packet bits to bitsets. Notice the reverse order of the bits sequence, required by the CNAV message decoder
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for (u32 i = 0; i < GPS_L5_CNAV_DATA_PAGE_BITS ; i++)
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{
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raw_bits[GPS_L5_CNAV_DATA_PAGE_BITS - 1 - i] = ((msg.raw_msg[i/8] >> (7 - i%8)) & 1u);
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}
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d_CNAV_Message.decode_page(raw_bits);
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//Push the new navigation data to the queues
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if (d_CNAV_Message.have_new_ephemeris() == true)
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{
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// get ephemeris object for this SV
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std::shared_ptr<Gps_CNAV_Ephemeris> tmp_obj = std::make_shared<Gps_CNAV_Ephemeris>(d_CNAV_Message.get_ephemeris());
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std::cout << "New GPS L5 CNAV message received: ephemeris from satellite " << d_satellite << std::endl;
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this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
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}
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if (d_CNAV_Message.have_new_iono() == true)
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{
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std::shared_ptr<Gps_CNAV_Iono> tmp_obj = std::make_shared<Gps_CNAV_Iono>(d_CNAV_Message.get_iono());
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std::cout << "New GPS L5 CNAV message received: iono model parameters from satellite " << d_satellite << std::endl;
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this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
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}
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if (d_CNAV_Message.have_new_utc_model() == true)
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{
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std::shared_ptr<Gps_CNAV_Utc_Model> tmp_obj = std::make_shared<Gps_CNAV_Utc_Model>(d_CNAV_Message.get_utc_model());
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std::cout << "New GPS L5 CNAV message received: UTC model parameters from satellite " << d_satellite << std::endl;
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this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
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}
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//update TOW at the preamble instant
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d_TOW_at_Preamble = static_cast<double>(msg.tow) * 6.0;
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//* The time of the last input symbol can be computed from the message ToW and
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//* delay by the formulae:
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//* \code
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//* symbolTime_ms = msg->tow * 6000 + *pdelay * 10 + (12 * 10); 12 symbols of the encoder's transitory
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d_TOW_at_current_symbol = (static_cast<double>(msg.tow) * 6.0) + (static_cast<double>(delay) + 12.0) * GPS_L5i_SYMBOL_PERIOD;
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d_TOW_at_current_symbol = floor(d_TOW_at_current_symbol * 1000.0) / 1000.0;
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d_flag_valid_word = true;
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}
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else
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{
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d_TOW_at_current_symbol += GPS_L5i_PERIOD;
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if (current_synchro_data.Flag_valid_symbol_output == false)
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{
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d_flag_valid_word = false;
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}
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}
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current_synchro_data.TOW_at_current_symbol_s = d_TOW_at_current_symbol;
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current_synchro_data.Flag_valid_word = d_flag_valid_word;
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if(d_dump == true)
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{
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// MULTIPLEXED FILE RECORDING - Record results to file
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try
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{
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double tmp_double;
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unsigned long int tmp_ulong_int;
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tmp_double = d_TOW_at_current_symbol;
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d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
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tmp_ulong_int = current_synchro_data.Tracking_sample_counter;
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d_dump_file.write(reinterpret_cast<char*>(&tmp_ulong_int), sizeof(unsigned long int));
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tmp_double = d_TOW_at_Preamble;
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d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
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}
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catch (const std::ifstream::failure & e)
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{
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LOG(WARNING) << "Exception writing Telemetry GPS L5 dump file " << e.what();
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}
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}
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//3. Make the output (copy the object contents to the GNURadio reserved memory)
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out[0] = current_synchro_data;
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return 1;
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}
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void gps_l5_telemetry_decoder_cc::set_satellite(const Gnss_Satellite & satellite)
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{
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d_satellite = Gnss_Satellite(satellite.get_system(), satellite.get_PRN());
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LOG(INFO) << "GPS L5 CNAV telemetry decoder in channel " << this->d_channel << " set to satellite " << d_satellite;
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d_CNAV_Message.reset();
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}
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void gps_l5_telemetry_decoder_cc::set_channel(int channel)
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{
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d_channel = channel;
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d_CNAV_Message.reset();
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LOG(INFO) << "GPS L5 CNAV channel set to " << channel;
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// ############# ENABLE DATA FILE LOG #################
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if (d_dump == true)
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{
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if (d_dump_file.is_open() == false)
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{
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try
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{
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d_dump_filename = "telemetry_L5_";
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d_dump_filename.append(boost::lexical_cast<std::string>(d_channel));
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d_dump_filename.append(".dat");
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d_dump_file.exceptions ( std::ifstream::failbit | std::ifstream::badbit );
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d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
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LOG(INFO) << "Telemetry decoder dump enabled on channel " << d_channel
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<< " Log file: " << d_dump_filename.c_str();
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}
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catch (const std::ifstream::failure &e)
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{
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LOG(WARNING) << "channel " << d_channel << " Exception opening Telemetry GPS L5 dump file " << e.what();
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}
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}
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}
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}
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