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/*!
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* \ file gps_l1_ca_dll_pll_c_aid_tracking_sc . cc
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* \ brief Implementation of a code DLL + carrier PLL tracking block
* \ author Javier Arribas , 2015. 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/>.
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
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# include "gps_l1_ca_dll_pll_c_aid_tracking_sc.h"
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# include <cmath>
# include <iostream>
# include <memory>
# include <sstream>
# include <boost/lexical_cast.hpp>
# include <gnuradio/io_signature.h>
# include <volk/volk.h>
# include <glog/logging.h>
# include "gnss_synchro.h"
# include "gps_sdr_signal_processing.h"
# include "tracking_discriminators.h"
# include "lock_detectors.h"
# include "GPS_L1_CA.h"
# include "control_message_factory.h"
/*!
* \ todo Include in definition header file
*/
# define CN0_ESTIMATION_SAMPLES 20
# define MINIMUM_VALID_CN0 25
# define MAXIMUM_LOCK_FAIL_COUNTER 50
# define CARRIER_LOCK_THRESHOLD 0.85
using google : : LogMessage ;
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gps_l1_ca_dll_pll_c_aid_tracking_sc_sptr
gps_l1_ca_dll_pll_c_aid_make_tracking_sc (
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long if_freq ,
long fs_in ,
unsigned int vector_length ,
boost : : shared_ptr < gr : : msg_queue > queue ,
bool dump ,
std : : string dump_filename ,
float pll_bw_hz ,
float dll_bw_hz ,
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float pll_bw_narrow_hz ,
float dll_bw_narrow_hz ,
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float early_late_space_chips )
{
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return gps_l1_ca_dll_pll_c_aid_tracking_sc_sptr ( new gps_l1_ca_dll_pll_c_aid_tracking_sc ( if_freq ,
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fs_in , vector_length , queue , dump , dump_filename , pll_bw_hz , dll_bw_hz , pll_bw_narrow_hz , dll_bw_narrow_hz , early_late_space_chips ) ) ;
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}
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void gps_l1_ca_dll_pll_c_aid_tracking_sc : : forecast ( int noutput_items ,
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gr_vector_int & ninput_items_required )
{
if ( noutput_items ! = 0 )
{
ninput_items_required [ 0 ] = static_cast < int > ( d_vector_length ) * 2 ; //set the required available samples in each call
}
}
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gps_l1_ca_dll_pll_c_aid_tracking_sc : : gps_l1_ca_dll_pll_c_aid_tracking_sc (
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long if_freq ,
long fs_in ,
unsigned int vector_length ,
boost : : shared_ptr < gr : : msg_queue > queue ,
bool dump ,
std : : string dump_filename ,
float pll_bw_hz ,
float dll_bw_hz ,
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float pll_bw_narrow_hz ,
float dll_bw_narrow_hz ,
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float early_late_space_chips ) :
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gr : : block ( " gps_l1_ca_dll_pll_c_aid_tracking_sc " , gr : : io_signature : : make ( 1 , 1 , sizeof ( lv_16sc_t ) ) ,
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gr : : io_signature : : make ( 1 , 1 , sizeof ( Gnss_Synchro ) ) )
{
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// Telemetry bit synchronization message port input
this - > message_port_register_in ( pmt : : mp ( " preamble_timestamp_s " ) ) ;
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// initialize internal vars
d_queue = queue ;
d_dump = dump ;
d_if_freq = if_freq ;
d_fs_in = fs_in ;
d_vector_length = vector_length ;
d_dump_filename = dump_filename ;
d_correlation_length_samples = static_cast < int > ( d_vector_length ) ;
// Initialize tracking ==========================================
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d_pll_bw_hz = pll_bw_hz ;
d_dll_bw_hz = dll_bw_hz ;
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d_pll_bw_narrow_hz = pll_bw_narrow_hz ;
d_dll_bw_narrow_hz = dll_bw_narrow_hz ;
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d_code_loop_filter . set_DLL_BW ( dll_bw_hz ) ;
d_carrier_loop_filter . set_params ( 10.0 , pll_bw_hz , 2 ) ;
//--- DLL variables --------------------------------------------------------
d_early_late_spc_chips = early_late_space_chips ; // Define early-late offset (in chips)
// Initialization of local code replica
// Get space for a vector with the C/A code replica sampled 1x/chip
d_ca_code = static_cast < gr_complex * > ( volk_malloc ( static_cast < int > ( GPS_L1_CA_CODE_LENGTH_CHIPS ) * sizeof ( gr_complex ) , volk_get_alignment ( ) ) ) ;
d_ca_code_16sc = static_cast < lv_16sc_t * > ( volk_malloc ( static_cast < int > ( GPS_L1_CA_CODE_LENGTH_CHIPS ) * sizeof ( lv_16sc_t ) , volk_get_alignment ( ) ) ) ;
// correlator outputs (scalar)
d_n_correlator_taps = 3 ; // Early, Prompt, and Late
d_correlator_outs_16sc = static_cast < lv_16sc_t * > ( volk_malloc ( d_n_correlator_taps * sizeof ( lv_16sc_t ) , volk_get_alignment ( ) ) ) ;
for ( int n = 0 ; n < d_n_correlator_taps ; n + + )
{
d_correlator_outs_16sc [ n ] = lv_16sc_t ( 0 , 0 ) ;
}
d_local_code_shift_chips = static_cast < float * > ( volk_malloc ( d_n_correlator_taps * sizeof ( float ) , volk_get_alignment ( ) ) ) ;
// Set TAPs delay values [chips]
d_local_code_shift_chips [ 0 ] = - d_early_late_spc_chips ;
d_local_code_shift_chips [ 1 ] = 0.0 ;
d_local_code_shift_chips [ 2 ] = d_early_late_spc_chips ;
multicorrelator_cpu_16sc . init ( 2 * d_correlation_length_samples , d_n_correlator_taps ) ;
//--- Perform initializations ------------------------------
// define initial code frequency basis of NCO
d_code_freq_chips = GPS_L1_CA_CODE_RATE_HZ ;
// define residual code phase (in chips)
d_rem_code_phase_samples = 0.0 ;
// define residual carrier phase
d_rem_carrier_phase_rad = 0.0 ;
// sample synchronization
d_sample_counter = 0 ;
//d_sample_counter_seconds = 0;
d_acq_sample_stamp = 0 ;
d_enable_tracking = false ;
d_pull_in = false ;
// CN0 estimation and lock detector buffers
d_cn0_estimation_counter = 0 ;
d_Prompt_buffer = new gr_complex [ CN0_ESTIMATION_SAMPLES ] ;
d_carrier_lock_test = 1 ;
d_CN0_SNV_dB_Hz = 0 ;
d_carrier_lock_fail_counter = 0 ;
d_carrier_lock_threshold = CARRIER_LOCK_THRESHOLD ;
systemName [ " G " ] = std : : string ( " GPS " ) ;
systemName [ " S " ] = std : : string ( " SBAS " ) ;
set_relative_rate ( 1.0 / ( static_cast < double > ( d_vector_length ) * 2.0 ) ) ;
d_acquisition_gnss_synchro = 0 ;
d_channel = 0 ;
d_acq_code_phase_samples = 0.0 ;
d_acq_carrier_doppler_hz = 0.0 ;
d_carrier_doppler_hz = 0.0 ;
d_acc_carrier_phase_cycles = 0.0 ;
d_code_phase_samples = 0.0 ;
d_pll_to_dll_assist_secs_Ti = 0.0 ;
d_rem_code_phase_chips = 0.0 ;
d_code_phase_step_chips = 0.0 ;
d_carrier_phase_step_rad = 0.0 ;
//set_min_output_buffer((long int)300);
}
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void gps_l1_ca_dll_pll_c_aid_tracking_sc : : start_tracking ( )
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{
/*
* correct the code phase according to the delay between acq and trk
*/
d_acq_code_phase_samples = d_acquisition_gnss_synchro - > Acq_delay_samples ;
d_acq_carrier_doppler_hz = d_acquisition_gnss_synchro - > Acq_doppler_hz ;
d_acq_sample_stamp = d_acquisition_gnss_synchro - > Acq_samplestamp_samples ;
long int acq_trk_diff_samples ;
double acq_trk_diff_seconds ;
acq_trk_diff_samples = static_cast < long int > ( d_sample_counter ) - static_cast < long int > ( d_acq_sample_stamp ) ; //-d_vector_length;
DLOG ( INFO ) < < " Number of samples between Acquisition and Tracking = " < < acq_trk_diff_samples ;
acq_trk_diff_seconds = static_cast < double > ( acq_trk_diff_samples ) / static_cast < double > ( d_fs_in ) ;
//doppler effect
// Fd=(C/(C+Vr))*F
double radial_velocity = ( GPS_L1_FREQ_HZ + d_acq_carrier_doppler_hz ) / GPS_L1_FREQ_HZ ;
// new chip and prn sequence periods based on acq Doppler
double T_chip_mod_seconds ;
double T_prn_mod_seconds ;
double T_prn_mod_samples ;
d_code_freq_chips = radial_velocity * GPS_L1_CA_CODE_RATE_HZ ;
d_code_phase_step_chips = static_cast < double > ( d_code_freq_chips ) / static_cast < double > ( d_fs_in ) ;
T_chip_mod_seconds = 1 / d_code_freq_chips ;
T_prn_mod_seconds = T_chip_mod_seconds * GPS_L1_CA_CODE_LENGTH_CHIPS ;
T_prn_mod_samples = T_prn_mod_seconds * static_cast < double > ( d_fs_in ) ;
d_correlation_length_samples = round ( T_prn_mod_samples ) ;
double T_prn_true_seconds = GPS_L1_CA_CODE_LENGTH_CHIPS / GPS_L1_CA_CODE_RATE_HZ ;
double T_prn_true_samples = T_prn_true_seconds * static_cast < double > ( d_fs_in ) ;
double T_prn_diff_seconds = T_prn_true_seconds - T_prn_mod_seconds ;
double N_prn_diff = acq_trk_diff_seconds / T_prn_true_seconds ;
double corrected_acq_phase_samples , delay_correction_samples ;
corrected_acq_phase_samples = fmod ( ( d_acq_code_phase_samples + T_prn_diff_seconds * N_prn_diff * static_cast < double > ( d_fs_in ) ) , T_prn_true_samples ) ;
if ( corrected_acq_phase_samples < 0 )
{
corrected_acq_phase_samples = T_prn_mod_samples + corrected_acq_phase_samples ;
}
delay_correction_samples = d_acq_code_phase_samples - corrected_acq_phase_samples ;
d_acq_code_phase_samples = corrected_acq_phase_samples ;
d_carrier_doppler_hz = d_acq_carrier_doppler_hz ;
d_carrier_phase_step_rad = GPS_TWO_PI * d_carrier_doppler_hz / static_cast < double > ( d_fs_in ) ;
// DLL/PLL filter initialization
d_carrier_loop_filter . initialize ( d_acq_carrier_doppler_hz ) ; //The carrier loop filter implements the Doppler accumulator
d_code_loop_filter . initialize ( ) ; // initialize the code filter
// generate local reference ALWAYS starting at chip 1 (1 sample per chip)
gps_l1_ca_code_gen_complex ( d_ca_code , d_acquisition_gnss_synchro - > PRN , 0 ) ;
volk_gnsssdr_32fc_convert_16ic ( d_ca_code_16sc , d_ca_code , static_cast < int > ( GPS_L1_CA_CODE_LENGTH_CHIPS ) ) ;
multicorrelator_cpu_16sc . set_local_code_and_taps ( static_cast < int > ( GPS_L1_CA_CODE_LENGTH_CHIPS ) , d_ca_code_16sc , d_local_code_shift_chips ) ;
for ( int n = 0 ; n < d_n_correlator_taps ; n + + )
{
d_correlator_outs_16sc [ n ] = lv_16sc_t ( 0 , 0 ) ;
}
d_carrier_lock_fail_counter = 0 ;
d_rem_code_phase_samples = 0.0 ;
d_rem_carrier_phase_rad = 0.0 ;
d_rem_code_phase_chips = 0.0 ;
d_acc_carrier_phase_cycles = 0.0 ;
d_pll_to_dll_assist_secs_Ti = 0.0 ;
d_code_phase_samples = d_acq_code_phase_samples ;
std : : string sys_ = & d_acquisition_gnss_synchro - > System ;
sys = sys_ . substr ( 0 , 1 ) ;
// DEBUG OUTPUT
std : : cout < < " Tracking start on channel " < < d_channel < < " for satellite " < < Gnss_Satellite ( systemName [ sys ] , d_acquisition_gnss_synchro - > PRN ) < < std : : endl ;
LOG ( INFO ) < < " Starting tracking of satellite " < < Gnss_Satellite ( systemName [ sys ] , d_acquisition_gnss_synchro - > PRN ) < < " on channel " < < d_channel ;
// enable tracking
d_pull_in = true ;
d_enable_tracking = true ;
LOG ( INFO ) < < " PULL-IN Doppler [Hz]= " < < d_carrier_doppler_hz
< < " Code Phase correction [samples]= " < < delay_correction_samples
< < " PULL-IN Code Phase [samples]= " < < d_acq_code_phase_samples ;
}
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gps_l1_ca_dll_pll_c_aid_tracking_sc : : ~ gps_l1_ca_dll_pll_c_aid_tracking_sc ( )
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{
d_dump_file . close ( ) ;
volk_free ( d_local_code_shift_chips ) ;
volk_free ( d_ca_code ) ;
volk_free ( d_ca_code_16sc ) ;
volk_free ( d_correlator_outs_16sc ) ;
delete [ ] d_Prompt_buffer ;
multicorrelator_cpu_16sc . free ( ) ;
}
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int gps_l1_ca_dll_pll_c_aid_tracking_sc : : 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 )
{
// Block input data and block output stream pointers
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const lv_16sc_t * in = ( lv_16sc_t * ) input_items [ 0 ] ; //PRN start block alignment
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Gnss_Synchro * * out = ( Gnss_Synchro * * ) & output_items [ 0 ] ;
// GNSS_SYNCHRO OBJECT to interchange data between tracking->telemetry_decoder
Gnss_Synchro current_synchro_data = Gnss_Synchro ( ) ;
// process vars
double code_error_chips_Ti = 0.0 ;
double code_error_filt_chips = 0.0 ;
double code_error_filt_secs_Ti = 0.0 ;
double CURRENT_INTEGRATION_TIME_S ;
double CORRECTED_INTEGRATION_TIME_S ;
double dll_code_error_secs_Ti = 0.0 ;
double carr_phase_error_secs_Ti = 0.0 ;
double old_d_rem_code_phase_samples ;
if ( d_enable_tracking = = true )
{
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// Fill the acquisition data
current_synchro_data = * d_acquisition_gnss_synchro ;
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// Receiver signal alignment
if ( d_pull_in = = true )
{
int samples_offset ;
double acq_trk_shif_correction_samples ;
int acq_to_trk_delay_samples ;
acq_to_trk_delay_samples = d_sample_counter - d_acq_sample_stamp ;
acq_trk_shif_correction_samples = d_correlation_length_samples - fmod ( static_cast < double > ( acq_to_trk_delay_samples ) , static_cast < double > ( d_correlation_length_samples ) ) ;
samples_offset = round ( d_acq_code_phase_samples + acq_trk_shif_correction_samples ) ;
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current_synchro_data . Tracking_timestamp_secs = ( static_cast < double > ( d_sample_counter ) + static_cast < double > ( d_rem_code_phase_samples ) ) / static_cast < double > ( d_fs_in ) ;
* out [ 0 ] = current_synchro_data ;
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d_sample_counter + = samples_offset ; //count for the processed samples
d_pull_in = false ;
consume_each ( samples_offset ) ; //shift input to perform alignment with local replica
return 1 ;
}
// ################# CARRIER WIPEOFF AND CORRELATORS ##############################
// perform carrier wipe-off and compute Early, Prompt and Late correlation
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multicorrelator_cpu_16sc . set_input_output_vectors ( d_correlator_outs_16sc , in ) ;
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multicorrelator_cpu_16sc . Carrier_wipeoff_multicorrelator_resampler ( d_rem_carrier_phase_rad , d_carrier_phase_step_rad , d_rem_code_phase_chips , d_code_phase_step_chips , d_correlation_length_samples ) ;
// UPDATE INTEGRATION TIME
CURRENT_INTEGRATION_TIME_S = static_cast < double > ( d_correlation_length_samples ) / static_cast < double > ( d_fs_in ) ;
// ################## PLL ##########################################################
// Update PLL discriminator [rads/Ti -> Secs/Ti]
carr_phase_error_secs_Ti = pll_cloop_two_quadrant_atan ( std : : complex < float > ( d_correlator_outs_16sc [ 1 ] . real ( ) , d_correlator_outs_16sc [ 1 ] . imag ( ) ) ) / GPS_TWO_PI ; //prompt output
// Carrier discriminator filter
// NOTICE: The carrier loop filter includes the Carrier Doppler accumulator, as described in Kaplan
//d_carrier_doppler_hz = d_acq_carrier_doppler_hz + carr_phase_error_filt_secs_ti/INTEGRATION_TIME;
// Input [s/Ti] -> output [Hz]
d_carrier_doppler_hz = d_carrier_loop_filter . get_carrier_error ( 0.0 , carr_phase_error_secs_Ti , CURRENT_INTEGRATION_TIME_S ) ;
// PLL to DLL assistance [Secs/Ti]
d_pll_to_dll_assist_secs_Ti = ( d_carrier_doppler_hz * CURRENT_INTEGRATION_TIME_S ) / GPS_L1_FREQ_HZ ;
// code Doppler frequency update
d_code_freq_chips = GPS_L1_CA_CODE_RATE_HZ + ( ( d_carrier_doppler_hz * GPS_L1_CA_CODE_RATE_HZ ) / GPS_L1_FREQ_HZ ) ;
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips_Ti = dll_nc_e_minus_l_normalized ( std : : complex < float > ( d_correlator_outs_16sc [ 0 ] . real ( ) , d_correlator_outs_16sc [ 0 ] . imag ( ) ) , std : : complex < float > ( d_correlator_outs_16sc [ 2 ] . real ( ) , d_correlator_outs_16sc [ 2 ] . imag ( ) ) ) ; //[chips/Ti] //early and late
// Code discriminator filter
code_error_filt_chips = d_code_loop_filter . get_code_nco ( code_error_chips_Ti ) ; //input [chips/Ti] -> output [chips/second]
code_error_filt_secs_Ti = code_error_filt_chips * CURRENT_INTEGRATION_TIME_S / d_code_freq_chips ; // [s/Ti]
// DLL code error estimation [s/Ti]
// TODO: PLL carrier aid to DLL is disabled. Re-enable it and measure performance
dll_code_error_secs_Ti = - code_error_filt_secs_Ti + d_pll_to_dll_assist_secs_Ti ;
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
// keep alignment parameters for the next input buffer
double T_chip_seconds ;
double T_prn_seconds ;
double T_prn_samples ;
double K_blk_samples ;
// Compute the next buffer length based in the new period of the PRN sequence and the code phase error estimation
T_chip_seconds = 1 / d_code_freq_chips ;
T_prn_seconds = T_chip_seconds * GPS_L1_CA_CODE_LENGTH_CHIPS ;
T_prn_samples = T_prn_seconds * static_cast < double > ( d_fs_in ) ;
K_blk_samples = T_prn_samples + d_rem_code_phase_samples - dll_code_error_secs_Ti * static_cast < double > ( d_fs_in ) ;
d_correlation_length_samples = round ( K_blk_samples ) ; //round to a discrete samples
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old_d_rem_code_phase_samples = d_rem_code_phase_samples ;
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d_rem_code_phase_samples = K_blk_samples - static_cast < double > ( d_correlation_length_samples ) ; //rounding error < 1 sample
// UPDATE REMNANT CARRIER PHASE
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CORRECTED_INTEGRATION_TIME_S = ( static_cast < double > ( d_correlation_length_samples ) / static_cast < double > ( d_fs_in ) ) ;
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//remnant carrier phase [rad]
d_rem_carrier_phase_rad = fmod ( d_rem_carrier_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * CORRECTED_INTEGRATION_TIME_S , GPS_TWO_PI ) ;
// UPDATE CARRIER PHASE ACCUULATOR
//carrier phase accumulator prior to update the PLL estimators (accumulated carrier in this loop depends on the old estimations!)
d_acc_carrier_phase_cycles - = d_carrier_doppler_hz * CORRECTED_INTEGRATION_TIME_S ;
//################### PLL COMMANDS #################################################
//carrier phase step (NCO phase increment per sample) [rads/sample]
d_carrier_phase_step_rad = GPS_TWO_PI * d_carrier_doppler_hz / static_cast < double > ( d_fs_in ) ;
//################### DLL COMMANDS #################################################
//code phase step (Code resampler phase increment per sample) [chips/sample]
d_code_phase_step_chips = d_code_freq_chips / static_cast < double > ( d_fs_in ) ;
//remnant code phase [chips]
d_rem_code_phase_chips = d_rem_code_phase_samples * ( d_code_freq_chips / static_cast < double > ( d_fs_in ) ) ;
// ####### CN0 ESTIMATION AND LOCK DETECTORS #######################################
if ( d_cn0_estimation_counter < CN0_ESTIMATION_SAMPLES )
{
// fill buffer with prompt correlator output values
d_Prompt_buffer [ d_cn0_estimation_counter ] = std : : complex < float > ( d_correlator_outs_16sc [ 1 ] . real ( ) , d_correlator_outs_16sc [ 1 ] . imag ( ) ) ; //prompt
d_cn0_estimation_counter + + ;
}
else
{
d_cn0_estimation_counter = 0 ;
// Code lock indicator
d_CN0_SNV_dB_Hz = cn0_svn_estimator ( d_Prompt_buffer , CN0_ESTIMATION_SAMPLES , d_fs_in , GPS_L1_CA_CODE_LENGTH_CHIPS ) ;
// Carrier lock indicator
d_carrier_lock_test = carrier_lock_detector ( d_Prompt_buffer , CN0_ESTIMATION_SAMPLES ) ;
// Loss of lock detection
if ( d_carrier_lock_test < d_carrier_lock_threshold or d_CN0_SNV_dB_Hz < MINIMUM_VALID_CN0 )
{
d_carrier_lock_fail_counter + + ;
}
else
{
if ( d_carrier_lock_fail_counter > 0 ) d_carrier_lock_fail_counter - - ;
}
if ( d_carrier_lock_fail_counter > MAXIMUM_LOCK_FAIL_COUNTER )
{
std : : cout < < " Loss of lock in channel " < < d_channel < < " ! " < < std : : endl ;
LOG ( INFO ) < < " Loss of lock in channel " < < d_channel < < " ! " ;
std : : unique_ptr < ControlMessageFactory > cmf ( new ControlMessageFactory ( ) ) ;
if ( d_queue ! = gr : : msg_queue : : sptr ( ) )
{
d_queue - > handle ( cmf - > GetQueueMessage ( d_channel , 2 ) ) ;
}
d_carrier_lock_fail_counter = 0 ;
d_enable_tracking = false ; // TODO: check if disabling tracking is consistent with the channel state machine
}
}
// ########### Output the tracking data to navigation and PVT ##########
current_synchro_data . Prompt_I = static_cast < double > ( ( d_correlator_outs_16sc [ 1 ] ) . real ( ) ) ;
current_synchro_data . Prompt_Q = static_cast < double > ( ( d_correlator_outs_16sc [ 1 ] ) . imag ( ) ) ;
// Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!)
current_synchro_data . Tracking_timestamp_secs = ( static_cast < double > ( d_sample_counter ) + old_d_rem_code_phase_samples ) / static_cast < double > ( d_fs_in ) ;
// This tracking block aligns the Tracking_timestamp_secs with the start sample of the PRN, thus, Code_phase_secs=0
current_synchro_data . Code_phase_secs = 0 ;
current_synchro_data . Carrier_phase_rads = GPS_TWO_PI * d_acc_carrier_phase_cycles ;
current_synchro_data . Carrier_Doppler_hz = d_carrier_doppler_hz ;
current_synchro_data . CN0_dB_hz = d_CN0_SNV_dB_Hz ;
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current_synchro_data . Flag_valid_symbol_output = true ;
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current_synchro_data . correlation_length_ms = 1 ;
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* out [ 0 ] = current_synchro_data ;
}
else
{
for ( int n = 0 ; n < d_n_correlator_taps ; n + + )
{
d_correlator_outs_16sc [ n ] = lv_16sc_t ( 0 , 0 ) ;
}
current_synchro_data . System = { ' G ' } ;
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current_synchro_data . Tracking_timestamp_secs = static_cast < double > ( d_sample_counter ) / static_cast < double > ( d_fs_in ) ;
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* out [ 0 ] = current_synchro_data ;
}
if ( d_dump )
{
// MULTIPLEXED FILE RECORDING - Record results to file
float prompt_I ;
float prompt_Q ;
float tmp_E , tmp_P , tmp_L ;
double tmp_double ;
prompt_I = d_correlator_outs_16sc [ 1 ] . real ( ) ;
prompt_Q = d_correlator_outs_16sc [ 1 ] . imag ( ) ;
tmp_E = std : : abs < float > ( std : : complex < float > ( d_correlator_outs_16sc [ 0 ] . real ( ) , d_correlator_outs_16sc [ 0 ] . imag ( ) ) ) ;
tmp_P = std : : abs < float > ( std : : complex < float > ( d_correlator_outs_16sc [ 1 ] . real ( ) , d_correlator_outs_16sc [ 1 ] . imag ( ) ) ) ;
tmp_L = std : : abs < float > ( std : : complex < float > ( d_correlator_outs_16sc [ 2 ] . real ( ) , d_correlator_outs_16sc [ 2 ] . imag ( ) ) ) ;
try
{
// EPR
d_dump_file . write ( reinterpret_cast < char * > ( & tmp_E ) , sizeof ( float ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & tmp_P ) , sizeof ( float ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & tmp_L ) , sizeof ( float ) ) ;
// PROMPT I and Q (to analyze navigation symbols)
d_dump_file . write ( reinterpret_cast < char * > ( & prompt_I ) , sizeof ( float ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & prompt_Q ) , sizeof ( float ) ) ;
// PRN start sample stamp
//tmp_float=(float)d_sample_counter;
d_dump_file . write ( reinterpret_cast < char * > ( & d_sample_counter ) , sizeof ( unsigned long int ) ) ;
// accumulated carrier phase
d_dump_file . write ( reinterpret_cast < char * > ( & d_acc_carrier_phase_cycles ) , sizeof ( double ) ) ;
// carrier and code frequency
d_dump_file . write ( reinterpret_cast < char * > ( & d_carrier_doppler_hz ) , sizeof ( double ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & d_code_freq_chips ) , sizeof ( double ) ) ;
//PLL commands
d_dump_file . write ( reinterpret_cast < char * > ( & carr_phase_error_secs_Ti ) , sizeof ( double ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & d_carrier_doppler_hz ) , sizeof ( double ) ) ;
//DLL commands
d_dump_file . write ( reinterpret_cast < char * > ( & code_error_chips_Ti ) , sizeof ( double ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & code_error_filt_chips ) , sizeof ( double ) ) ;
// CN0 and carrier lock test
d_dump_file . write ( reinterpret_cast < char * > ( & d_CN0_SNV_dB_Hz ) , sizeof ( double ) ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & d_carrier_lock_test ) , sizeof ( double ) ) ;
// AUX vars (for debug purposes)
tmp_double = d_rem_code_phase_samples ;
d_dump_file . write ( reinterpret_cast < char * > ( & tmp_double ) , sizeof ( double ) ) ;
tmp_double = static_cast < double > ( d_sample_counter + d_correlation_length_samples ) ;
d_dump_file . write ( reinterpret_cast < char * > ( & tmp_double ) , sizeof ( double ) ) ;
}
catch ( const std : : ifstream : : failure * e )
{
LOG ( WARNING ) < < " Exception writing trk dump file " < < e - > what ( ) ;
}
}
consume_each ( d_correlation_length_samples ) ; // this is necessary in gr::block derivates
d_sample_counter + = d_correlation_length_samples ; //count for the processed samples
return 1 ; //output tracking result ALWAYS even in the case of d_enable_tracking==false
}
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void gps_l1_ca_dll_pll_c_aid_tracking_sc : : set_channel ( unsigned int channel )
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{
d_channel = channel ;
LOG ( INFO ) < < " Tracking Channel set to " < < d_channel ;
// ############# ENABLE DATA FILE LOG #################
if ( d_dump = = true )
{
if ( d_dump_file . is_open ( ) = = false )
{
try
{
d_dump_filename . append ( boost : : lexical_cast < std : : string > ( d_channel ) ) ;
d_dump_filename . append ( " .dat " ) ;
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 ) < < " Tracking dump enabled on channel " < < d_channel < < " Log file: " < < d_dump_filename . c_str ( ) < < std : : endl ;
}
catch ( const std : : ifstream : : failure * e )
{
LOG ( WARNING ) < < " channel " < < d_channel < < " Exception opening trk dump file " < < e - > what ( ) < < std : : endl ;
}
}
}
}
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void gps_l1_ca_dll_pll_c_aid_tracking_sc : : set_gnss_synchro ( Gnss_Synchro * p_gnss_synchro )
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{
d_acquisition_gnss_synchro = p_gnss_synchro ;
}