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Bug fixes in GPS CA L1 20 extended correlator

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This commit is contained in:
Javier Arribas 2016-03-15 17:58:58 +01:00
parent 6e076e8143
commit 6c2f3d8f43
2 changed files with 22 additions and 13 deletions
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30
src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_cc.cc
View File

@ -198,6 +198,7 @@ gps_l1_ca_dll_pll_c_aid_tracking_cc::gps_l1_ca_dll_pll_c_aid_tracking_cc(
d_acq_code_phase_samples = 0.0;
d_acq_carrier_doppler_hz = 0.0;
d_carrier_doppler_hz = 0.0;
d_code_error_filt_chips_Ti = 0.0;
d_acc_carrier_phase_cycles = 0.0;
d_code_phase_samples = 0.0;
@ -324,8 +325,8 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
// process vars
double code_error_filt_secs_Ti = 0.0;
double CURRENT_INTEGRATION_TIME_S;
double CORRECTED_INTEGRATION_TIME_S;
double CURRENT_INTEGRATION_TIME_S = 0.0;
double CORRECTED_INTEGRATION_TIME_S = 0.0;
double dll_code_error_secs_Ti = 0.0;
double old_d_rem_code_phase_samples;
if (d_enable_tracking == true)
@ -392,14 +393,16 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
if (d_preamble_synchronized==false)
{
d_code_loop_filter.set_DLL_BW(d_dll_bw_narrow_hz);
d_carrier_loop_filter.set_params(10.0, d_pll_bw_narrow_hz,2);
d_preamble_synchronized=true;
std::cout<<"dll="<<d_dll_bw_hz<<" dll_n="<<d_dll_bw_narrow_hz<<" pll="<<d_pll_bw_hz<<" pll_n="<<d_pll_bw_narrow_hz<<std::endl;
}
current_synchro_data.symbol_integration_enabled=true;
// UPDATE INTEGRATION TIME
CURRENT_INTEGRATION_TIME_S = static_cast<double>(GPS_CA_TELEMETRY_SYMBOLS_PER_BIT)*GPS_L1_CA_CODE_PERIOD;
d_code_loop_filter.set_DLL_BW(d_dll_bw_narrow_hz);
d_carrier_loop_filter.set_params(10.0, d_pll_bw_narrow_hz,2);
enable_dll_pll=true;
}else{
@ -407,7 +410,9 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
if(d_preamble_synchronized==true)
{
// continue extended coherent correlation
d_rem_carrier_phase_rad = fmod(d_rem_carrier_phase_rad + d_carrier_phase_step_rad * d_correlation_length_samples, GPS_TWO_PI);
//remnant carrier phase [rads]
d_rem_carrier_phase_rad = fmod(d_rem_carrier_phase_rad + d_carrier_phase_step_rad * static_cast<double>(d_correlation_length_samples), GPS_TWO_PI);
// Compute the next buffer length based on the period of the PRN sequence and the code phase error estimation
double T_chip_seconds = 1 / d_code_freq_chips;
@ -416,8 +421,7 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
int K_prn_samples = round(T_prn_samples);
double K_T_prn_error_samples=K_prn_samples-T_prn_samples;
old_d_rem_code_phase_samples=d_rem_code_phase_samples;
d_rem_code_phase_samples= d_rem_code_phase_samples - K_T_prn_error_samples -dll_code_error_secs_Ti * static_cast<double>(d_fs_in);
d_rem_code_phase_samples= d_rem_code_phase_samples - K_T_prn_error_samples;
d_rem_code_phase_integer_samples=round(d_rem_code_phase_samples);
d_correlation_length_samples = K_prn_samples + d_rem_code_phase_integer_samples; //round to a discrete samples
d_rem_code_phase_samples=d_rem_code_phase_samples-d_rem_code_phase_integer_samples;
@ -463,10 +467,12 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
// DLL discriminator
d_code_error_chips_Ti = dll_nc_e_minus_l_normalized(d_correlator_outs[0], d_correlator_outs[2]); //[chips/Ti] //early and late
// Code discriminator filter
d_code_error_filt_chips = d_code_loop_filter.get_code_nco(d_code_error_chips_Ti); //input [chips/Ti] -> output [chips/second]
code_error_filt_secs_Ti = d_code_error_filt_chips*CURRENT_INTEGRATION_TIME_S/d_code_freq_chips; // [s/Ti]
d_code_error_filt_chips_s = d_code_loop_filter.get_code_nco(d_code_error_chips_Ti); //input [chips/Ti] -> output [chips/second]
d_code_error_filt_chips_Ti = d_code_error_filt_chips_s*CURRENT_INTEGRATION_TIME_S;
code_error_filt_secs_Ti = d_code_error_filt_chips_Ti/d_code_freq_chips; // [s/Ti]
// DLL code error estimation [s/Ti]
dll_code_error_secs_Ti = - code_error_filt_secs_Ti + d_pll_to_dll_assist_secs_Ti;
// PLL to DLL assistance is disable due to the use of a fractional resampler that allows the correction of the code Doppler effect.
dll_code_error_secs_Ti = - code_error_filt_secs_Ti;// + d_pll_to_dll_assist_secs_Ti;
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
@ -663,14 +669,14 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
//DLL commands
d_dump_file.write(reinterpret_cast<char*>(&d_code_error_chips_Ti), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_code_error_filt_chips), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&d_code_error_filt_chips_Ti), 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_code_phase_step_chips;
tmp_double = d_code_error_chips_Ti*CURRENT_INTEGRATION_TIME_S;
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));

5
src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_cc.h
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@ -48,6 +48,7 @@
#include "gnss_synchro.h"
#include "tracking_2nd_DLL_filter.h"
#include "tracking_FLL_PLL_filter.h"
#include "tracking_loop_filter.h"
#include "cpu_multicorrelator.h"
class gps_l1_ca_dll_pll_c_aid_tracking_cc;
@ -141,6 +142,7 @@ private:
int d_rem_code_phase_integer_samples;
// PLL and DLL filter library
//Tracking_2nd_DLL_filter d_code_loop_filter;
Tracking_2nd_DLL_filter d_code_loop_filter;
Tracking_FLL_PLL_filter d_carrier_loop_filter;
@ -161,7 +163,8 @@ private:
double d_code_phase_samples;
double d_pll_to_dll_assist_secs_Ti;
double d_code_error_chips_Ti;
double d_code_error_filt_chips;
double d_code_error_filt_chips_s;
double d_code_error_filt_chips_Ti;
double d_carr_phase_error_secs_Ti;
// symbol history to detect bit transition