diff --git a/conf/gnss-sdr_Hybrid_byte_sim.conf b/conf/gnss-sdr_Hybrid_byte_sim.conf index 1ebb882fc..9730e6363 100644 --- a/conf/gnss-sdr_Hybrid_byte_sim.conf +++ b/conf/gnss-sdr_Hybrid_byte_sim.conf @@ -158,7 +158,7 @@ Resampler.sample_freq_out=2600000 ;######### CHANNELS GLOBAL CONFIG ############ ;#count: Number of available GPS satellite channels. -Channels_1C.count=10 +Channels_1C.count=12 ;#count: Number of available Galileo satellite channels. Channels_1B.count=0 ;#in_acquisition: Number of channels simultaneously acquiring for the whole receiver @@ -250,7 +250,7 @@ Tracking_1C.dump_filename=../data/epl_tracking_ch_ Tracking_1C.pll_bw_hz=20.0; ;#dll_bw_hz: DLL loop filter bandwidth [Hz] -Tracking_1C.dll_bw_hz=2.0; +Tracking_1C.dll_bw_hz=1.5; ;#fll_bw_hz: FLL loop filter bandwidth [Hz] Tracking_1C.fll_bw_hz=10.0; diff --git a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_artemisa_tracking_cc.cc b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_artemisa_tracking_cc.cc index 9cc70d150..6c287a4c2 100644 --- a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_artemisa_tracking_cc.cc +++ b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_artemisa_tracking_cc.cc @@ -290,13 +290,10 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ double code_error_chips_Ti=0.0; double code_error_filt_chips=0.0; double code_error_filt_secs_Ti=0.0; - double INTEGRATION_TIME; - INTEGRATION_TIME=GPS_L1_CA_CODE_PERIOD; // [Ti] + double CURRENT_INTEGRATION_TIME_S; double dll_code_error_secs_Ti=0.0; double carr_phase_error_secs_Ti=0.0; - double carr_phase_error_filt_secs_ti=0.0; double old_d_rem_code_phase_samples; - double old_d_acc_carrier_phase_cycles; if (d_enable_tracking == true) { // Receiver signal alignment @@ -320,37 +317,42 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ // Fill the acquisition data current_synchro_data = *d_acquisition_gnss_synchro; + // ################# CARRIER WIPEOFF AND CORRELATORS ############################## + // perform carrier wipe-off and compute Early, Prompt and Late correlation multicorrelator_cpu.set_input_output_vectors(d_correlator_outs,in); - - // ################# perform carrier wipe-off and compute Early, Prompt and Late correlation ################ multicorrelator_cpu.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_current_prn_length_samples); + // UPDATE INTEGRATION TIME + CURRENT_INTEGRATION_TIME_S=(static_cast(d_current_prn_length_samples)/static_cast(d_fs_in)); + // UPDATE REMNANT CARRIER PHASE + //remnant carrier phase [rad] + d_rem_carrier_phase_rad = fmod(d_rem_carrier_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * CURRENT_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*CURRENT_INTEGRATION_TIME_S; + + // ################## PLL ########################################################## + // Update PLL discriminator [rads/Ti -> Secs/Ti] + carr_phase_error_secs_Ti = pll_cloop_two_quadrant_atan(d_correlator_outs[1])/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(d_correlator_outs[0], d_correlator_outs[2]); //[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*GPS_L1_CA_CHIP_PERIOD*GPS_L1_CA_CODE_PERIOD; // [s/Ti] + 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] dll_code_error_secs_Ti=-code_error_filt_secs_Ti+d_pll_to_dll_assist_secs_Ti; - // ################## PLL ########################################################## - // PLL discriminator [rads/Ti -> Secs/Ti] - carr_phase_error_secs_Ti = pll_cloop_two_quadrant_atan(d_correlator_outs[1])/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, INTEGRATION_TIME); - //carrier phase accumulator for (K) doppler estimation - //d_acc_carrier_phase_cycles -= (d_carrier_doppler_hz*INTEGRATION_TIME); - old_d_acc_carrier_phase_cycles=d_acc_carrier_phase_cycles; - d_acc_carrier_phase_cycles += static_cast(d_carrier_doppler_hz)*d_current_prn_length_samples/static_cast(d_fs_in);//INTEGRATION_TIME; - // PLL to DLL assistance [Secs/Ti] - d_pll_to_dll_assist_secs_Ti = (d_carrier_doppler_hz*GPS_L1_CA_CODE_PERIOD)/GPS_L1_FREQ_HZ; - // code frequency (include code Doppler estimation here) - d_code_freq_chips = GPS_L1_CA_CODE_RATE_HZ + ((d_carrier_doppler_hz * GPS_L1_CA_CODE_RATE_HZ) / GPS_L1_FREQ_HZ);//GPS_L1_CA_CODE_RATE_HZ; - // ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT ####################### // keep alignment parameters for the next input buffer double T_chip_seconds; @@ -358,10 +360,10 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ 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 / static_cast(d_code_freq_chips); + 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(d_fs_in); - K_blk_samples = T_prn_samples + d_rem_code_phase_samples - static_cast(dll_code_error_secs_Ti) * static_cast(d_fs_in); + K_blk_samples = T_prn_samples + d_rem_code_phase_samples - dll_code_error_secs_Ti * static_cast(d_fs_in); d_current_prn_length_samples = round(K_blk_samples); //round to a discrete samples old_d_rem_code_phase_samples=d_rem_code_phase_samples; d_rem_code_phase_samples = K_blk_samples - static_cast(d_current_prn_length_samples); //rounding error < 1 sample @@ -369,16 +371,15 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ //################### 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(d_fs_in); - //remnant carrier phase [rad] - d_rem_carrier_phase_rad = fmod(d_rem_carrier_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * GPS_L1_CA_CODE_PERIOD,GPS_TWO_PI);//GPS_TWO_PI*carr_phase_error_filt_secs_ti; //################### DLL COMMANDS ################################################# //code phase step (Code resampler phase increment per sample) [chips/sample] - d_code_phase_step_chips = static_cast(d_code_freq_chips) / static_cast(d_fs_in); + d_code_phase_step_chips = d_code_freq_chips / static_cast(d_fs_in); //remnant code phase [chips] d_rem_code_phase_chips = d_rem_code_phase_samples * (d_code_freq_chips / static_cast(d_fs_in)); - // ####### CN0 ESTIMATION AND LOCK DETECTORS ###### + + // ####### CN0 ESTIMATION AND LOCK DETECTORS ####################################### if (d_cn0_estimation_counter < CN0_ESTIMATION_SAMPLES) { // fill buffer with prompt correlator output values @@ -415,19 +416,16 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ } } - // ########### Output the tracking data to navigation and PVT ########## current_synchro_data.Prompt_I = static_cast((d_correlator_outs[1]).real()); current_synchro_data.Prompt_Q = static_cast((d_correlator_outs[1]).imag()); - - // Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!, but some glitches??) + // Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!) current_synchro_data.Tracking_timestamp_secs = (static_cast(d_sample_counter) + old_d_rem_code_phase_samples) / static_cast(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*static_cast(d_acc_carrier_phase_cycles); - current_synchro_data.Carrier_Doppler_hz = static_cast(d_carrier_doppler_hz); - current_synchro_data.CN0_dB_hz = static_cast(d_CN0_SNV_dB_Hz); + 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; current_synchro_data.Flag_valid_pseudorange = false; *out[0] = current_synchro_data; @@ -492,7 +490,6 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ float prompt_I; float prompt_Q; float tmp_E, tmp_P, tmp_L; - float tmp_float; double tmp_double; prompt_I = d_correlator_outs[1].real(); prompt_Q = d_correlator_outs[1].imag(); @@ -548,8 +545,6 @@ int gps_l1_ca_dll_pll_artemisa_tracking_cc::general_work (int noutput_items, gr_ return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false } - - void gps_l1_ca_dll_pll_artemisa_tracking_cc::set_channel(unsigned int channel) { d_channel = channel; diff --git a/src/core/system_parameters/GPS_L1_CA.h b/src/core/system_parameters/GPS_L1_CA.h index 3c4a3bd0d..a2cef3d95 100644 --- a/src/core/system_parameters/GPS_L1_CA.h +++ b/src/core/system_parameters/GPS_L1_CA.h @@ -53,7 +53,7 @@ const double GPS_L1_FREQ_HZ = 1.57542e9; //!< L1 [Hz] const double GPS_L1_CA_CODE_RATE_HZ = 1.023e6; //!< GPS L1 C/A code rate [chips/s] const double GPS_L1_CA_CODE_LENGTH_CHIPS = 1023.0; //!< GPS L1 C/A code length [chips] const double GPS_L1_CA_CODE_PERIOD = 0.001; //!< GPS L1 C/A code period [seconds] -const double GPS_L1_CA_CHIP_PERIOD = 1.0e-6; //!< GPS L1 C/A chip period [seconds] +const double GPS_L1_CA_CHIP_PERIOD = 9.7752e-07; //!< GPS L1 C/A chip period [seconds] /*! * \brief Maximum Time-Of-Arrival (TOA) difference between satellites for a receiver operated on Earth surface is 20 ms