Fixing bugs in extended correlator for GPS L1

conf/gnss-sdr_Hybrid_gr_complex.conf

@@ -0,0 +1,347 @@
+; Default configuration file
+; You can define your own receiver and invoke it by doing
+; gnss-sdr --config_file=my_GNSS_SDR_configuration.conf
+;
+
+[GNSS-SDR]
+
+;######### GLOBAL OPTIONS ##################
+;internal_fs_hz: Internal signal sampling frequency after the signal conditioning stage [Hz].
+GNSS-SDR.internal_fs_hz=4092000
+
+;######### CONTROL_THREAD CONFIG ############
+ControlThread.wait_for_flowgraph=false
+;######### SIGNAL_SOURCE CONFIG ############
+;#implementation: Use [File_Signal_Source] [Nsr_File_Signal_Source] or [UHD_Signal_Source] or [GN3S_Signal_Source] (experimental)
+SignalSource.implementation=File_Signal_Source
+
+;#filename: path to file with the captured GNSS signal samples to be processed
+SignalSource.filename=/home/javier/signals/GPS_sim1.dat
+
+;#item_type: Type and resolution for each of the signal samples. Use only gr_complex in this version.
+SignalSource.item_type=gr_complex
+
+;#sampling_frequency: Original Signal sampling frequency in [Hz]
+SignalSource.sampling_frequency=4092000
+
+;#freq: RF front-end center frequency in [Hz]
+SignalSource.freq=1575420000
+
+;#samples: Number of samples to be processed. Notice that 0 indicates the entire file.
+SignalSource.samples=0
+
+;#repeat: Repeat the processing file. Disable this option in this version
+SignalSource.repeat=false
+
+;#dump: Dump the Signal source data to a file. Disable this option in this version
+SignalSource.dump=false
+
+SignalSource.dump_filename=../data/signal_source.dat
+
+
+;#enable_throttle_control: Enabling this option tells the signal source to keep the delay between samples in post processing.
+; it helps to not overload the CPU, but the processing time will be longer.
+SignalSource.enable_throttle_control=false
+
+
+;######### SIGNAL_CONDITIONER CONFIG ############
+;## It holds blocks to change data type, filter and resample input data.
+
+;#implementation: Use [Pass_Through] or [Signal_Conditioner]
+;#[Pass_Through] disables this block and the [DataTypeAdapter], [InputFilter] and [Resampler] blocks
+;#[Signal_Conditioner] enables this block. Then you have to configure [DataTypeAdapter], [InputFilter] and [Resampler] blocks
+SignalConditioner.implementation=Pass_Through
+
+;######### DATA_TYPE_ADAPTER CONFIG ############
+;## Changes the type of input data.
+;#implementation: [Pass_Through] disables this block
+DataTypeAdapter.implementation=Pass_Through
+DataTypeAdapter.item_type=gr_complex
+
+;######### INPUT_FILTER CONFIG ############
+;## Filter the input data. Can be combined with frequency translation for IF signals
+
+;#implementation: Use [Pass_Through] or [Fir_Filter] or [Freq_Xlating_Fir_Filter]
+;#[Freq_Xlating_Fir_Filter] enables FIR filter and a composite frequency translation
+;# that shifts IF down to zero Hz.
+
+InputFilter.implementation=Pass_Through
+
+;#dump: Dump the filtered data to a file.
+InputFilter.dump=false
+
+;#dump_filename: Log path and filename.
+InputFilter.dump_filename=../data/input_filter.dat
+
+;#The following options are used in the filter design of Fir_Filter and Freq_Xlating_Fir_Filter implementation.
+;#These options are based on parameters of gnuradio's function: gr_remez.
+;#These function calculates the optimal (in the Chebyshev/minimax sense) FIR filter inpulse
+;#reponse given a set of band edges, the desired reponse on those bands,
+;#and the weight given to the error in those bands.
+
+;#input_item_type: Type and resolution for input signal samples. Use only gr_complex in this version.
+InputFilter.input_item_type=gr_complex
+
+;#outut_item_type: Type and resolution for output filtered signal samples. Use only gr_complex in this version.
+InputFilter.output_item_type=gr_complex
+
+;#taps_item_type: Type and resolution for the taps of the filter. Use only float in this version.
+InputFilter.taps_item_type=float
+
+;#number_of_taps: Number of taps in the filter. Increasing this parameter increases the processing time
+InputFilter.number_of_taps=5
+
+;#number_of _bands: Number of frequency bands in the filter.
+InputFilter.number_of_bands=2
+
+;#bands: frequency at the band edges [ b1 e1 b2 e2 b3 e3 ...].
+;#Frequency is in the range [0, 1], with 1 being the Nyquist frequency (Fs/2)
+;#The number of band_begin and band_end elements must match the number of bands
+
+InputFilter.band1_begin=0.0
+InputFilter.band1_end=0.45
+InputFilter.band2_begin=0.55
+InputFilter.band2_end=1.0
+
+;#ampl: desired amplitude at the band edges [ a(b1) a(e1) a(b2) a(e2) ...].
+;#The number of ampl_begin and ampl_end elements must match the number of bands
+
+InputFilter.ampl1_begin=1.0
+InputFilter.ampl1_end=1.0
+InputFilter.ampl2_begin=0.0
+InputFilter.ampl2_end=0.0
+
+;#band_error: weighting applied to each band (usually 1).
+;#The number of band_error elements must match the number of bands
+InputFilter.band1_error=1.0
+InputFilter.band2_error=1.0
+
+;#filter_type: one of "bandpass", "hilbert" or "differentiator"
+InputFilter.filter_type=bandpass
+
+;#grid_density: determines how accurately the filter will be constructed.
+;The minimum value is 16; higher values are slower to compute the filter.
+InputFilter.grid_density=16
+
+;# Original sampling frequency stored in the signal file
+InputFilter.sampling_frequency=4092000
+
+;#The following options are used only in Freq_Xlating_Fir_Filter implementation.
+;#InputFilter.IF is the intermediate frequency (in Hz) shifted down to zero Hz
+
+InputFilter.IF=5499998.47412109
+
+;# Decimation factor after the frequency tranaslating block
+InputFilter.decimation_factor=8
+
+
+;######### RESAMPLER CONFIG ############
+;## Resamples the input data.
+
+;#implementation: Use [Pass_Through] or [Direct_Resampler]
+;#[Pass_Through] disables this block
+;#[Direct_Resampler] enables a resampler that implements a nearest neigbourhood interpolation
+Resampler.implementation=Pass_Through
+
+;######### CHANNELS GLOBAL CONFIG ############
+;#count: Number of available GPS satellite channels.
+Channels_1C.count=1
+;#count: Number of available Galileo satellite channels.
+Channels_1B.count=0
+;#in_acquisition: Number of channels simultaneously acquiring for the whole receiver
+Channels.in_acquisition=1
+
+;#signal:
+;# "1C" GPS L1 C/A
+;# "2S" GPS L2 L2C (M)
+;# "1B" GALILEO E1 B (I/NAV OS/CS/SoL)
+;# "5X" GALILEO E5a I+Q
+
+;#if the option is disabled by default is assigned "1C" GPS L1 C/A
+Channel0.signal=1C
+Channel1.signal=1B
+Channel2.signal=1B
+Channel3.signal=1B
+Channel4.signal=1B
+Channel5.signal=1B
+Channel6.signal=1B
+Channel7.signal=1B
+Channel8.signal=1B
+Channel9.signal=1B
+Channel10.signal=1B
+Channel11.signal=1B
+Channel12.signal=1B
+Channel13.signal=1B
+Channel14.signal=1B
+Channel15.signal=1B
+
+
+;######### GPS ACQUISITION CONFIG ############
+
+;#dump: Enable or disable the acquisition internal data file logging [true] or [false]
+Acquisition_1C.dump=false
+;#filename: Log path and filename
+Acquisition_1C.dump_filename=./acq_dump.dat
+;#item_type: Type and resolution for each of the signal samples. Use only gr_complex in this version.
+Acquisition_1C.item_type=gr_complex
+;#if: Signal intermediate frequency in [Hz]
+Acquisition_1C.if=0
+;#sampled_ms: Signal block duration for the acquisition signal detection [ms]
+Acquisition_1C.sampled_ms=1
+;#implementation: Acquisition algorithm selection for this channel: [GPS_L1_CA_PCPS_Acquisition] or [Galileo_E1_PCPS_Ambiguous_Acquisition]
+Acquisition_1C.implementation=GPS_L1_CA_PCPS_Acquisition
+Acquisition_1C.use_CFAR_algorithm=false;
+;#threshold: Acquisition threshold
+Acquisition_1C.threshold=30
+;#pfa: Acquisition false alarm probability. This option overrides the threshold option. Only use with implementations: [GPS_L1_CA_PCPS_Acquisition] or [Galileo_E1_PCPS_Ambiguous_Acquisition]
+;Acquisition_1C.pfa=0.01
+;#doppler_max: Maximum expected Doppler shift [Hz]
+Acquisition_1C.doppler_max=5000
+;#doppler_max: Doppler step in the grid search [Hz]
+Acquisition_1C.doppler_step=100
+
+
+;######### GALILEO ACQUISITION CONFIG ############
+
+;#dump: Enable or disable the acquisition internal data file logging [true] or [false]
+Acquisition_1B.dump=false
+;#filename: Log path and filename
+Acquisition_1B.dump_filename=./acq_dump.dat
+;#item_type: Type and resolution for each of the signal samples. Use only gr_complex in this version.
+Acquisition_1B.item_type=gr_complex
+;#if: Signal intermediate frequency in [Hz]
+Acquisition_1B.if=0
+;#sampled_ms: Signal block duration for the acquisition signal detection [ms]
+Acquisition_1B.sampled_ms=4
+;#implementation: Acquisition algorithm selection for this channel: [GPS_L1_CA_PCPS_Acquisition] or [Galileo_E1_PCPS_Ambiguous_Acquisition]
+Acquisition_1B.implementation=Galileo_E1_PCPS_Ambiguous_Acquisition
+;#threshold: Acquisition threshold
+;Acquisition_1B.threshold=0
+;#pfa: Acquisition false alarm probability. This option overrides the threshold option. Only use with implementations: [GPS_L1_CA_PCPS_Acquisition] or [Galileo_E1_PCPS_Ambiguous_Acquisition]
+Acquisition_1B.pfa=0.0000002
+;#doppler_max: Maximum expected Doppler shift [Hz]
+Acquisition_1B.doppler_max=15000
+;#doppler_max: Doppler step in the grid search [Hz]
+Acquisition_1B.doppler_step=125
+
+;######### TRACKING GPS CONFIG ############
+
+;#implementation: Selected tracking algorithm: [GPS_L1_CA_DLL_PLL_Tracking] or [GPS_L1_CA_DLL_FLL_PLL_Tracking] or [GPS_L1_CA_TCP_CONNECTOR_Tracking] or [Galileo_E1_DLL_PLL_VEML_Tracking]
+Tracking_1C.implementation=GPS_L1_CA_DLL_PLL_C_Aid_Tracking
+;#item_type: Type and resolution for each of the signal samples. Use only [gr_complex] in this version.
+Tracking_1C.item_type=gr_complex
+
+;#sampling_frequency: Signal Intermediate Frequency in [Hz]
+Tracking_1C.if=0
+
+;#dump: Enable or disable the Tracking internal binary data file logging [true] or [false]
+Tracking_1C.dump=true
+
+;#dump_filename: Log path and filename. Notice that the tracking channel will add "x.dat" where x is the channel number.
+Tracking_1C.dump_filename=../data/epl_tracking_ch_
+
+;#pll_bw_hz: PLL loop filter bandwidth [Hz]
+Tracking_1C.pll_bw_hz=20;
+Tracking_1C.pll_bw_narrow_hz=5;
+
+;#dll_bw_hz: DLL loop filter bandwidth [Hz]
+Tracking_1C.dll_bw_hz=4.0;
+
+Tracking_1C.dll_bw_narrow_hz=1.5;
+
+;#fll_bw_hz: FLL loop filter bandwidth [Hz]
+Tracking_1C.fll_bw_hz=2.0;
+
+;#order: PLL/DLL loop filter order [2] or [3]
+Tracking_1C.order=3;
+
+;######### TRACKING GALILEO CONFIG ############
+
+;#implementation: Selected tracking algorithm: [GPS_L1_CA_DLL_PLL_Tracking] or [GPS_L1_CA_DLL_FLL_PLL_Tracking] or [GPS_L1_CA_TCP_CONNECTOR_Tracking] or [Galileo_E1_DLL_PLL_VEML_Tracking]
+Tracking_1B.implementation=Galileo_E1_DLL_PLL_VEML_Tracking
+;#item_type: Type and resolution for each of the signal samples. Use only [gr_complex] in this version.
+Tracking_1B.item_type=gr_complex
+
+;#sampling_frequency: Signal Intermediate Frequency in [Hz]
+Tracking_1B.if=0
+
+;#dump: Enable or disable the Tracking internal binary data file logging [true] or [false]
+Tracking_1B.dump=false
+
+;#dump_filename: Log path and filename. Notice that the tracking channel will add "x.dat" where x is the channel number.
+Tracking_1B.dump_filename=../data/veml_tracking_ch_
+
+;#pll_bw_hz: PLL loop filter bandwidth [Hz]
+Tracking_1B.pll_bw_hz=15.0;
+
+;#dll_bw_hz: DLL loop filter bandwidth [Hz]
+Tracking_1B.dll_bw_hz=2.0;
+
+;#fll_bw_hz: FLL loop filter bandwidth [Hz]
+Tracking_1B.fll_bw_hz=10.0;
+
+;#order: PLL/DLL loop filter order [2] or [3]
+Tracking_1B.order=3;
+
+;#early_late_space_chips: correlator early-late space [chips]. Use [0.5] for GPS and [0.15] for Galileo
+Tracking_1B.early_late_space_chips=0.15;
+
+;#very_early_late_space_chips: only for [Galileo_E1_DLL_PLL_VEML_Tracking], correlator very early-late space [chips]. Use [0.6]
+Tracking_1B.very_early_late_space_chips=0.6;
+
+
+;######### TELEMETRY DECODER GPS CONFIG ############
+;#implementation: Use [GPS_L1_CA_Telemetry_Decoder] for GPS L1 C/A
+TelemetryDecoder_1C.implementation=GPS_L1_CA_Telemetry_Decoder
+TelemetryDecoder_1C.dump=false
+;#decimation factor
+TelemetryDecoder_1C.decimation_factor=4;
+
+;######### TELEMETRY DECODER GALILEO CONFIG ############
+;#implementation: Use [Galileo_E1B_Telemetry_Decoder] for Galileo E1B
+TelemetryDecoder_1B.implementation=Galileo_E1B_Telemetry_Decoder
+TelemetryDecoder_1B.dump=false
+TelemetryDecoder_1B_factor=4;
+
+;######### OBSERVABLES CONFIG ############
+;#implementation: Use [GPS_L1_CA_Observables] for GPS L1 C/A.
+Observables.implementation=Hybrid_Observables
+
+;#dump: Enable or disable the Observables internal binary data file logging [true] or [false]
+Observables.dump=false
+
+;#dump_filename: Log path and filename.
+Observables.dump_filename=./observables.dat
+
+
+;######### PVT CONFIG ############
+;#implementation: Position Velocity and Time (PVT) implementation algorithm: Use [GPS_L1_CA_PVT] in this version.
+PVT.implementation=Hybrid_PVT
+
+;#averaging_depth: Number of PVT observations in the moving average algorithm
+PVT.averaging_depth=10
+
+;#flag_average: Enables the PVT averaging between output intervals (arithmetic mean) [true] or [false]
+PVT.flag_averaging=false
+
+;#output_rate_ms: Period between two PVT outputs. Notice that the minimum period is equal to the tracking integration time (for GPS CA L1 is 1ms) [ms]
+PVT.output_rate_ms=10;
+
+;#display_rate_ms: Position console print (std::out) interval [ms]. Notice that output_rate_ms<=display_rate_ms.
+PVT.display_rate_ms=500;
+
+;#dump: Enable or disable the PVT internal binary data file logging [true] or [false]
+PVT.dump=false
+
+PVT.flag_rtcm_server=false
+PVT.flag_rtcm_tty_port=false
+PVT.rtcm_dump_devname=/dev/pts/1
+
+;#dump_filename: Log path and filename without extension. Notice that PVT will add ".dat" to the binary dump and ".kml" to GoogleEarth dump.
+PVT.dump_filename=./PVT
+
+;######### OUTPUT_FILTER CONFIG ############
+;# Receiver output filter: Leave this block disabled in this version
+OutputFilter.implementation=Null_Sink_Output_Filter
+OutputFilter.filename=data/gnss-sdr.dat
+OutputFilter.item_type=gr_complex

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_cc.cc

@@ -323,13 +323,10 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
     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)
         {
@@ -396,6 +393,7 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
 		            if (d_preamble_synchronized==false)
 		            {
 		            		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
@@ -409,10 +407,25 @@ 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_correlation_length_samples=d_correlation_length_samples-d_rem_code_phase_integer_samples;
-						d_rem_code_phase_integer_samples=0;
 						d_rem_carrier_phase_rad = fmod(d_rem_carrier_phase_rad + d_carrier_phase_step_rad * d_correlation_length_samples, GPS_TWO_PI);
-						d_rem_code_phase_chips = fmod(d_rem_code_phase_chips + d_code_phase_step_chips*d_correlation_length_samples,GPS_L1_CA_CODE_LENGTH_CHIPS);
+
+						// 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;
+						double T_prn_seconds = T_chip_seconds * GPS_L1_CA_CODE_LENGTH_CHIPS;
+						double T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
+						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_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;
+						//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));
+
 						// disable tracking loop and inform telemetry decoder
 						enable_dll_pll=false;
 					}else{
@@ -435,12 +448,12 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
 			{
 				// ################## 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
+				d_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);
+				d_carrier_doppler_hz = d_carrier_loop_filter.get_carrier_error(0.0, d_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
@@ -448,10 +461,10 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
 
 				// ################## 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
+				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
-				code_error_filt_chips = d_code_loop_filter.get_code_nco(code_error_chips_Ti); //input [chips/Ti] -> output [chips/second]
+				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 = code_error_filt_chips*CURRENT_INTEGRATION_TIME_S/d_code_freq_chips; // [s/Ti]
+				code_error_filt_secs_Ti = d_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;
 
@@ -645,19 +658,19 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items, gr_vec
                     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_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*>(&d_code_error_chips_Ti), sizeof(double));
-                    d_dump_file.write(reinterpret_cast<char*>(&code_error_filt_chips), sizeof(double));
+                    d_dump_file.write(reinterpret_cast<char*>(&d_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;
+                    tmp_double = d_code_phase_step_chips;
                     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));

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_cc.h

@@ -160,6 +160,9 @@ private:
     double d_acc_carrier_phase_cycles;
     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_carr_phase_error_secs_Ti;
 
     // symbol history to detect bit transition
     std::deque<gr_complex> d_E_history;

src/algorithms/tracking/libs/cpu_multicorrelator.cc

@@ -85,22 +85,21 @@ bool cpu_multicorrelator::set_input_output_vectors(std::complex<float>* corr_out
     return true;
 }
 
-
-
 void cpu_multicorrelator::update_local_code(int correlator_length_samples,float rem_code_phase_chips, float code_phase_step_chips)
 {
-    float local_code_chip_index;
+    int local_code_chip_index;
     for (int current_correlator_tap = 0; current_correlator_tap < d_n_correlators; current_correlator_tap++)
-        {
+	{
-            for (int n = 0; n < correlator_length_samples; n++)
+		for (int n = 0; n < correlator_length_samples; n++)
-                {
+		{
-                    // resample code for current tap
+		   // resample code for current tap
-                    local_code_chip_index = std::fmod(code_phase_step_chips*static_cast<float>(n)+ d_shifts_chips[current_correlator_tap] - rem_code_phase_chips, d_code_length_chips);
+		   local_code_chip_index = floor(code_phase_step_chips*static_cast<float>(n) + d_shifts_chips[current_correlator_tap]- rem_code_phase_chips);
-                    //Take into account that in multitap correlators, the shifts can be negative!
+		   local_code_chip_index = local_code_chip_index % d_code_length_chips;
-                    if (local_code_chip_index < 0.0) local_code_chip_index += d_code_length_chips;
+		   //Take into account that in multitap correlators, the shifts can be negative!
-                    d_local_codes_resampled[current_correlator_tap][n] = d_local_code_in[static_cast<int>(round(local_code_chip_index))];
+		   if (local_code_chip_index < 0) local_code_chip_index += d_code_length_chips;
-                }
+		   d_local_codes_resampled[current_correlator_tap][n] = d_local_code_in[local_code_chip_index];
-        }
+		}
+	}
 }