Simulink tracking block updated: generation of the Simulink model from a script MATLAB and improvement of the tracking algorithm (both PLL and DLL). Added multi-threading support for MATLAB.

git-svn-id: https://svn.code.sf.net/p/gnss-sdr/code/trunk@208 64b25241-fba3-4117-9849-534c7e92360d
2025-04-12 22:03:20 +00:00 · 2012-07-03 12:52:12 +00:00 · 2012-07-03 12:52:12 +00:00 · aab40c963d
commit aab40c963d
parent fb287c0de3
13 changed files with 58208 additions and 3028 deletions
--- a/conf/gnss-sdr_tcp_connector_tracking.conf
+++ b/conf/gnss-sdr_tcp_connector_tracking.conf
@ -9,7 +9,7 @@ GNSS-SDR.internal_fs_hz=4000000
 ControlThread.wait_for_flowgraph=false

 ;######### SIGNAL_SOURCE CONFIG ############
-;#implementation: Use only File_Signal_Source in this version
+;#implementation: Use 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
@ -20,6 +20,7 @@ SignalSource.item_type=gr_complex

 ;#sampling_frequency: Original Signal sampling frequency in [Hz] 
 SignalSource.sampling_frequency=4000000
+;SignalSource.sampling_frequency=100000000

 ;#freq: RF front-end center frequency in [Hz] 
 SignalSource.freq=1575420000
@ -32,10 +33,6 @@ SignalSource.subdevice=B:0

 ;#samples: Number of samples to be processed. Notice that 0 indicates the entire file.
 SignalSource.samples=0
-;SignalSource.samples=80000000
-;SignalSource.samples=40000000
-;SignalSource.samples=20000000
-

 ;#repeat: Repeat the processing file. Disable this option in this version
 SignalSource.repeat=false
@ -43,10 +40,15 @@ 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
+
+SignalSource.dump_filename=../data/SignalSource.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: Pass_Through disables this block
@ -68,7 +70,7 @@ InputFilter.implementation=Pass_Through
 InputFilter.dump=false

 ;#dump_filename: Log path and filename.
-InputFilter.dump=../data/input_filter.dat
+InputFilter.dump_filename=../data/input_filter.dat

 ;#The following options are used in the filter design of Fir_Filter implementation. 
 ;#These options are based on parameters of gnuradio's function: gr_remez.
@ -142,8 +144,8 @@ Resampler.sample_freq_out=4000000

 ;######### CHANNELS GLOBAL CONFIG ############
 ;#count: Number of available satellite channels.
-Channels.count=8
-Channels.in_acquisition=8
+Channels.count=7
+Channels.in_acquisition=7

 ;######### CHANNEL 0 CONFIG ############
 ;#system: GPS, GLONASS, GALILEO, SBAS or COMPASS
@ -210,42 +212,55 @@ Channel0.system=GPS
 Channel0.signal=1C

 ;#satellite: Satellite PRN ID for this channel. Disable this option to random search
-;Channel0.satellite=2
+;Channel0.satellite=15
+;Channel0.repeat_satellite=true

 ;######### CHANNEL 1 CONFIG ############

 Channel1.system=GPS
 Channel1.signal=1C
-;Channel1.satellite=14
+;Channel1.satellite=18
+;Channel1.repeat_satellite=true

 ;######### CHANNEL 2 CONFIG ############

 Channel2.system=GPS
 Channel2.signal=1C
-;Channel2.satellite=21
+;Channel2.satellite=16
+;Channel2.repeat_satellite=true

 ;######### CHANNEL 3 CONFIG ############

 Channel3.system=GPS
 Channel3.signal=1C
-;Channel3.satellite=13
+;Channel3.satellite=23
+;Channel3.repeat_satellite=true
+
+;######### CHANNEL 4 CONFIG ############
+
+Channel4.system=GPS
+Channel4.signal=1C
+;Channel4.satellite=3
+;Channel4.repeat_satellite=true
+
+;######### CHANNEL 3 CONFIG ############
+
+Channel5.system=GPS
+Channel5.signal=1C
+;Channel5.satellite=21
+;Channel5.repeat_satellite=true


 ;######### ACQUISITION GLOBAL CONFIG ############

 ;#dump: Enable or disable the acquisition internal data file logging [true] or [false] 
 Acquisition.dump=false
-
 ;#filename: Log path and filename
 Acquisition.dump_filename=./acq_dump.dat
-
 ;#item_type: Type and resolution for each of the signal samples. Use only gr_complex in this version.
 Acquisition.item_type=gr_complex
-
-
 ;#if: Signal intermediate frequency in [Hz] 
 Acquisition.if=0
-
 ;#sampled_ms: Signal block duration for the acquisition signal detection [ms]
 Acquisition.sampled_ms=1

@ -254,74 +269,77 @@ Acquisition.sampled_ms=1
 ;######### ACQUISITION CH 0 CONFIG ############
 ;#implementation: Acquisition algorithm selection for this channel: [GPS_L1_CA_PCPS_Acquisition]
 Acquisition0.implementation=GPS_L1_CA_PCPS_Acquisition
-
 ;#threshold: Acquisition threshold
-Acquisition0.threshold=70
-
+Acquisition0.threshold=100
 ;#doppler_max: Maximum expected Doppler shift [Hz]
 Acquisition0.doppler_max=10000
-
 ;#doppler_max: Doppler step in the grid search [Hz]
 Acquisition0.doppler_step=250
+;#repeat_satellite: Use only jointly with the satellite PRN ID option. 

-;#repeat_satellite: Use only jointly with the satellte PRN ID option. 
-;#Enable repeat_satellite to keep searching the same satellite during the runtime.
-;Acquisition0.repeat_satellite=true

 ;######### ACQUISITION CH 1 CONFIG ############
 Acquisition1.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition1.threshold=70
+Acquisition1.threshold=100
 Acquisition1.doppler_max=10000
 Acquisition1.doppler_step=250
-;Acquisition1.repeat_satellite=true
+

 ;######### ACQUISITION CH 2 CONFIG ############
 Acquisition2.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition2.threshold=70
+Acquisition2.threshold=100
 Acquisition2.doppler_max=10000
 Acquisition2.doppler_step=250
-;Acquisition2.repeat_satellite=true
+

 ;######### ACQUISITION CH 3 CONFIG ############
 Acquisition3.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition3.threshold=70
+Acquisition3.threshold=100
 Acquisition3.doppler_max=10000
 Acquisition3.doppler_step=250
-;Acquisition3.repeat_satellite=true
+

 ;######### ACQUISITION CH 4 CONFIG ############
 Acquisition4.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition4.threshold=70
+Acquisition4.threshold=100
 Acquisition4.doppler_max=10000
 Acquisition4.doppler_step=250
-;Acquisition4.repeat_satellite=true
+

 ;######### ACQUISITION CH 5 CONFIG ############
 Acquisition5.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition5.threshold=70
+Acquisition5.threshold=100
 Acquisition5.doppler_max=10000
 Acquisition5.doppler_step=250
-;Acquisition5.repeat_satellite=true
+

 ;######### ACQUISITION CH 6 CONFIG ############
 Acquisition6.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition6.threshold=70
+Acquisition6.threshold=100
 Acquisition6.doppler_max=10000
 Acquisition6.doppler_step=250
-;Acquisition6.repeat_satellite=true
+

 ;######### ACQUISITION CH 7 CONFIG ############
 Acquisition7.implementation=GPS_L1_CA_PCPS_Acquisition
-Acquisition7.threshold=70
+Acquisition7.threshold=100
 Acquisition7.doppler_max=10000
 Acquisition7.doppler_step=250
-;Acquisition7.repeat_satellite=true
+
+
+;######### ACQUISITION CH 8 CONFIG ############
+Acquisition8.implementation=GPS_L1_CA_PCPS_Acquisition
+Acquisition8.threshold=100
+Acquisition8.doppler_max=10000
+Acquisition8.doppler_step=250
+
+

 ;######### TRACKING GLOBAL CONFIG ############

 ;#implementatiion: Selected tracking algorithm: [GPS_L1_CA_DLL_PLL_Tracking], [GPS_L1_CA_DLL_FLL_PLL_Tracking] or [GPS_L1_CA_TCP_CONNECTOR_Tracking]
-Tracking.implementation=GPS_L1_CA_TCP_CONNECTOR_Tracking
-
+Tracking.implementation= GPS_L1_CA_TCP_CONNECTOR_Tracking
+;Tracking.implementation=GPS_L1_CA_DLL_FLL_PLL_Tracking
 ;#item_type: Type and resolution for each of the signal samples. Use only [gr_complex] in this version.
 Tracking.item_type=gr_complex

@ -341,7 +359,7 @@ Tracking.pll_bw_hz=50.0;
 Tracking.dll_bw_hz=2.0;

 ;#fll_bw_hz: FLL loop filter bandwidth [Hz]
-Tracking.fll_bw_hz=20.0;
+Tracking.fll_bw_hz=10.0;

 ;#order: PLL/DLL loop filter order [2] or [3]
 Tracking.order=2;
@ -350,19 +368,17 @@ Tracking.order=2;
 Tracking.early_late_space_chips=0.5;

 ;#port_ch0: local TCP port for channel 0
-Tracking.port_ch0=2060;
+Tracking.port_ch0=2070;

 ;######### TELEMETRY DECODER CONFIG ############
 ;#implementation: Use [GPS_L1_CA_Telemetry_Decoder] for GPS L1 C/A.
 TelemetryDecoder.implementation=GPS_L1_CA_Telemetry_Decoder
+TelemetryDecoder.dump=false

 ;######### OBSERVABLES CONFIG ############
 ;#implementation: Use [GPS_L1_CA_Observables] for GPS L1 C/A.
 Observables.implementation=GPS_L1_CA_Observables

-;#output_rate_ms: Period between two psudoranges outputs. Notice that the minimum period is equal to the tracking integration time (for GPS CA L1 is 1ms) [ms]
-Observables.output_rate_ms=100
-
 ;#dump: Enable or disable the Observables internal binary data file logging [true] or [false] 
 Observables.dump=false

@ -375,11 +391,18 @@ Observables.dump_filename=./observables.dat
 PVT.implementation=GPS_L1_CA_PVT

 ;#averaging_depth: Number of PVT observations in the moving average algorithm
+;PVT.averaging_depth=100
 PVT.averaging_depth=2

 ;#flag_average: Enables the PVT averaging between output intervals (arithmetic mean) [true] or [false] 
 PVT.flag_averaging=true

+;#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=100;
+
+;#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

--- a/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_tcp_connector_tracking_cc.cc
+++ b/src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_tcp_connector_tracking_cc.cc
@ -61,8 +61,8 @@
 #define CN0_ESTIMATION_SAMPLES 10
 #define MINIMUM_VALID_CN0 25
 #define MAXIMUM_LOCK_FAIL_COUNTER 200
-#define NUM_TX_VARIABLES 7
-#define NUM_RX_VARIABLES 3
+#define NUM_TX_VARIABLES 9
+#define NUM_RX_VARIABLES 4

 using google::LogMessage;

@ -190,6 +190,7 @@ Gps_L1_Ca_Tcp_Connector_Tracking_cc::Gps_L1_Ca_Tcp_Connector_Tracking_cc(
    systemName["S"] = std::string("SBAS");
    systemName["E"] = std::string("Galileo");
    systemName["C"] = std::string("Compass");
+
 }

 void Gps_L1_Ca_Tcp_Connector_Tracking_cc::start_tracking()
@ -204,6 +205,15 @@ void Gps_L1_Ca_Tcp_Connector_Tracking_cc::start_tracking()

    unsigned long int acq_trk_diff_samples;
    float acq_trk_diff_seconds;
+    // jarribas: this patch correct a situation where the tracking sample counter
+    // is equal to 0 (remains in the initial state) at the first acquisition to tracking transition
+    // of the receiver operation when is connecting to simulink server.
+//    if (d_sample_counter<d_acq_sample_stamp)
+//    {
+//    	acq_trk_diff_samples=0; //disable the correction
+//    }else{
+//    	acq_trk_diff_samples = d_sample_counter - d_acq_sample_stamp;//-d_vector_length;
+//    }
    acq_trk_diff_samples = d_sample_counter - d_acq_sample_stamp;//-d_vector_length;
    std::cout << "acq_trk_diff_samples=" << acq_trk_diff_samples << std::endl;
    acq_trk_diff_seconds = (float)acq_trk_diff_samples / (float)d_fs_in;
@ -341,6 +351,7 @@ tcp_packet_data::tcp_packet_data() {

 	proc_pack_code_error = 0;
    proc_pack_carr_error = 0;
+    proc_pack_carrier_doppler_hz = 0;
 }

 tcp_packet_data::~tcp_packet_data() {
@ -363,13 +374,6 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec

    tcp_packet_data tcp_data;

-	//! Listen for connections on a TCP port
-    if (d_listen_connection == true)
-	{
-		d_port = d_port_ch0 + d_channel;
-		d_listen_connection = d_tcp_com.listen_tcp_connection(d_port);
-	}
-
    if (d_enable_tracking == true)
        {
            /*
@ -448,25 +452,17 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
            d_control_id++;

            //! Send and receive a TCP packet
-            boost::array<float, NUM_TX_VARIABLES> tx_variables_array = {{(*d_Early).imag(),(*d_Early).real(),(*d_Late).imag(),(*d_Late).real(),(*d_Prompt).imag(),(*d_Prompt).real(), d_control_id}};
-            d_tcp_com.send_receive_tcp_packet(tx_variables_array, &tcp_data);
+             boost::array<float, NUM_TX_VARIABLES> tx_variables_array = {{d_control_id,(*d_Early).imag(),(*d_Early).real(),(*d_Late).imag(),(*d_Late).real(),(*d_Prompt).imag(),(*d_Prompt).real(),d_acq_carrier_doppler_hz,1}};
+             d_tcp_com.send_receive_tcp_packet(tx_variables_array, &tcp_data);

-            //! Recover the data
-            code_error = tcp_data.proc_pack_code_error;
-            carr_error = tcp_data.proc_pack_carr_error;
-
-
-            // Compute PLL error and update carrier NCO -
-//SIM            carr_error = pll_cloop_two_quadrant_atan(*d_Prompt) / (float)GPS_TWO_PI;
-            // Implement carrier loop filter and generate NCO command
-            carr_nco = d_carrier_loop_filter.get_carrier_nco(carr_error);
-            // Modify carrier freq based on NCO command
-            d_carrier_doppler_hz = d_acq_carrier_doppler_hz + carr_nco;
-
-            // Compute DLL error and update code NCO
-//SIM            code_error = dll_nc_e_minus_l_normalized(*d_Early, *d_Late);
+             //! Recover the tracking data
+             code_error = tcp_data.proc_pack_code_error;
+             carr_error = tcp_data.proc_pack_carr_error;
+             // Modify carrier freq based on NCO command
+             d_carrier_doppler_hz = tcp_data.proc_pack_carrier_doppler_hz;
            // Modify code freq based on NCO command
-            d_code_freq_hz = 1/(1/GPS_L1_CA_CODE_RATE_HZ - code_nco/GPS_L1_CA_CODE_LENGTH_CHIPS);
+            code_nco=1/(1/GPS_L1_CA_CODE_RATE_HZ-code_error/GPS_L1_CA_CODE_LENGTH_CHIPS);
+            d_code_freq_hz = code_nco;

            // Update the phasestep based on code freq (variable) and
            // sampling frequency (fixed)
@ -480,7 +476,18 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
            T_prn_seconds = T_chip_seconds * GPS_L1_CA_CODE_LENGTH_CHIPS;
            T_prn_samples = T_prn_seconds * d_fs_in;
            d_rem_code_phase_samples = d_next_rem_code_phase_samples;
-            K_blk_samples = T_prn_samples + d_rem_code_phase_samples;
+            K_blk_samples = T_prn_samples + d_rem_code_phase_samples;//-code_error*(float)d_fs_in;
+
+            // Update the current PRN delay (code phase in samples)
+            float T_prn_true_seconds = GPS_L1_CA_CODE_LENGTH_CHIPS / GPS_L1_CA_CODE_RATE_HZ;
+            float T_prn_true_samples = T_prn_true_seconds * (float)d_fs_in;
+            d_code_phase_samples = d_code_phase_samples + T_prn_samples - T_prn_true_samples;
+            if (d_code_phase_samples < 0)
+                {
+                    d_code_phase_samples = T_prn_true_samples + d_code_phase_samples;
+                }
+
+            d_code_phase_samples = fmod(d_code_phase_samples, T_prn_true_samples);
            d_next_prn_length_samples = round(K_blk_samples); //round to a discrete samples
            d_next_rem_code_phase_samples = K_blk_samples - d_next_prn_length_samples; //rounding error

@ -511,8 +518,6 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
                    if (d_carrier_lock_fail_counter > MAXIMUM_LOCK_FAIL_COUNTER)
                        {
                            std::cout << "Channel " << d_channel << " loss of lock!" << std::endl ;
-//                            tracking_message = 3; //loss of lock
-//                            d_channel_internal_queue->push(tracking_message);
                        	ControlMessageFactory* cmf = new ControlMessageFactory();
                        	if (d_queue != gr_msg_queue_sptr()) {
                        		d_queue->handle(cmf->GetQueueMessage(d_channel, 2));
@ -522,9 +527,18 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
                            d_enable_tracking = false; // TODO: check if disabling tracking is consistent with the channel state machine

                        }
-                    //std::cout<<"d_carrier_lock_fail_counter"<<d_carrier_lock_fail_counter<<"\r\n";
                }

+            // ########### Output the tracking data to navigation and PVT ##########
+
+            current_synchro_data.Prompt_I = (double)(*d_Prompt).imag();
+            current_synchro_data.Prompt_Q = (double)(*d_Prompt).real();
+            current_synchro_data.Tracking_timestamp_secs = d_sample_counter_seconds;
+            current_synchro_data.Carrier_phase_rads = (double)d_acc_carrier_phase_rad;
+            current_synchro_data.Code_phase_secs = (double)d_code_phase_samples * (1/(float)d_fs_in);
+            current_synchro_data.CN0_dB_hz = (double)d_CN0_SNV_dB_Hz;
+            *out[0] = current_synchro_data;
+
            // ########## DEBUG OUTPUT
            /*!
             *  \todo The stop timer has to be moved to the signal source!
@ -538,8 +552,6 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
                            std::cout << "Current input signal time = " << d_last_seg << " [s]" << std::endl;
                            std::cout << "Tracking CH " << d_channel <<  ": Satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN)
                                                    << ", CN0 = " << d_CN0_SNV_dB_Hz << " [dB-Hz]" << std::endl;
-                            //std::cout<<"TRK CH "<<d_channel<<" Carrier_lock_test="<<d_carrier_lock_test<< std::endl;
-                            //if (d_last_seg==5) d_carrier_lock_fail_counter=500; //DEBUG: force unlock!
                        }
                }
            else
@ -549,22 +561,8 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
                            d_last_seg = floor(d_sample_counter / d_fs_in);
                            std::cout << "Tracking CH " << d_channel <<  ": Satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN)
                                                    << ", CN0 = " << d_CN0_SNV_dB_Hz << " [dB-Hz]" << std::endl;
-                            //std::cout<<"TRK CH "<<d_channel<<" Carrier_lock_test="<<d_carrier_lock_test<< std::endl;
                        }
                }
-
-            // ########### Output the tracking data to navigation and PVT ##########
-
-            current_synchro_data.Prompt_I = (double)(*d_Prompt).imag();
-            current_synchro_data.Prompt_Q = (double)(*d_Prompt).real();
-            // Tracking_timestamp_secs is aligned with the PRN start sample
-            current_synchro_data.Tracking_timestamp_secs=((double)d_sample_counter+(double)d_next_prn_length_samples+(double)d_next_rem_code_phase_samples)/(double)d_fs_in;
-            // This tracking block aligns the Tracking_timestamp_secs with the start sample of the PRN, Code_phase_secs=0
-            current_synchro_data.Code_phase_secs=0;
-            current_synchro_data.Tracking_timestamp_secs = d_sample_counter_seconds;
-            current_synchro_data.Carrier_phase_rads = (double)d_acc_carrier_phase_rad;
-            current_synchro_data.CN0_dB_hz = (double)d_CN0_SNV_dB_Hz;
-            *out[0] = current_synchro_data;
        }
    else
        {
@ -572,13 +570,12 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
            *d_Prompt = gr_complex(0,0);
            *d_Late = gr_complex(0,0);
            Gnss_Synchro **out = (Gnss_Synchro **) &output_items[0]; //block output streams pointer
-            //std::cout<<output_items.size()<<std::endl;
            // GNSS_SYNCHRO OBJECT to interchange data between tracking->telemetry_decoder
            Gnss_Synchro current_synchro_data;
            *out[0] = current_synchro_data;

            //! When tracking is disabled an array of 1's is sent to maintain the TCP connection
-            boost::array<float, NUM_TX_VARIABLES> tx_variables_array = {{1,1,1,1,1,1,1}};
+            boost::array<float, NUM_TX_VARIABLES> tx_variables_array = {{1,1,1,1,1,1,1,1,0}};
            d_tcp_com.send_receive_tcp_packet(tx_variables_array, &tcp_data);
        }

@ -589,7 +586,6 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
            float prompt_Q;
            float tmp_E, tmp_P, tmp_L;
            float tmp_float;
-            double tmp_double;
            prompt_I = (*d_Prompt).imag();
            prompt_Q = (*d_Prompt).real();
            tmp_E = std::abs<float>(*d_Early);
@ -627,10 +623,9 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
                    d_dump_file.write((char*)&d_carrier_lock_test, sizeof(float));

                    // AUX vars (for debug purposes)
-                    tmp_float = d_rem_code_phase_samples;
+                    tmp_float=0;
                    d_dump_file.write((char*)&tmp_float, sizeof(float));
-                    tmp_double=(double)(d_sample_counter+d_current_prn_length_samples);
-                    d_dump_file.write((char*)&tmp_double, sizeof(double));
+                    d_dump_file.write((char*)&d_sample_counter_seconds, sizeof(double));
            }
            catch (std::ifstream::failure e)
            {
@ -639,7 +634,7 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items, gr_vec
        }

    consume_each(d_current_prn_length_samples); // this is necesary in gr_block derivates
-    //d_sample_counter_seconds = d_sample_counter_seconds + ( ((double)d_current_prn_length_samples) / (double)d_fs_in );
+    d_sample_counter_seconds = d_sample_counter_seconds + ( ((double)d_current_prn_length_samples) / (double)d_fs_in );
    d_sample_counter += d_current_prn_length_samples; //count for the processed samples
    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
 }
@ -669,6 +664,13 @@ void Gps_L1_Ca_Tcp_Connector_Tracking_cc::set_channel(unsigned int channel)
                    }
                }
        }
+
+	//! Listen for connections on a TCP port
+    if (d_listen_connection == true)
+	{
+		d_port = d_port_ch0 + d_channel;
+		d_listen_connection = d_tcp_com.listen_tcp_connection(d_port,d_port_ch0);
+	}
 }


--- a/src/algorithms/tracking/libs/tcp_communication.cc
+++ b/src/algorithms/tracking/libs/tcp_communication.cc
@ -35,8 +35,8 @@
 #include <string>


-#define NUM_TX_VARIABLES 7
-#define NUM_RX_VARIABLES 3
+#define NUM_TX_VARIABLES 9
+#define NUM_RX_VARIABLES 4


 tcp_communication::tcp_communication() : tcp_socket_(io_service_)
@ -49,7 +49,7 @@ tcp_communication::~tcp_communication()



-int tcp_communication::listen_tcp_connection(size_t d_port_)
+int tcp_communication::listen_tcp_connection(size_t d_port_, size_t d_port_ch0_)
 {
    try
    {
@ -57,11 +57,14 @@ int tcp_communication::listen_tcp_connection(size_t d_port_)
            boost::asio::ip::tcp::endpoint endpoint(boost::asio::ip::tcp::v4(), d_port_);
            boost::asio::ip::tcp::acceptor acceptor(io_service_, endpoint);

+	    	if (d_port_ == d_port_ch0_)
+    		{
+	    		std::cout << "Server ready. Listening for TCP connections..." << std::endl;
+    		}
+
            // Reuse the IP address for each connection
            acceptor.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true));

-            std::cout << "Server ready on port " << d_port_ << std::endl;
-
            // Listen for a connection and accept it
            acceptor.listen(12);
            acceptor.accept(tcp_socket_);
@ -81,9 +84,9 @@ int tcp_communication::listen_tcp_connection(size_t d_port_)

 void tcp_communication::send_receive_tcp_packet(boost::array<float, NUM_TX_VARIABLES> buf, tcp_packet_data *tcp_data_)
 {
-    int controlc = 0;
-    boost::array<float, NUM_RX_VARIABLES> readbuf;
-    float d_control_id_ = buf.data()[6];
+	int controlc = 0;
+	boost::array<float, NUM_RX_VARIABLES> readbuf;
+	float d_control_id_ = buf.data()[0];

    try
    {
@ -92,16 +95,17 @@ void tcp_communication::send_receive_tcp_packet(boost::array<float, NUM_TX_VARIA

            // Read the received TCP packet
            tcp_socket_.read_some(boost::asio::buffer(readbuf));
+    	
+    		//! Control. The GNSS-SDR program ends if an error in a TCP packet is detected.
+	    	if (d_control_id_ != readbuf.data()[0])
+    		{
+    			throw "Packet error!";
+    		}

-            // Recover the variables received
-            tcp_data_->proc_pack_code_error = readbuf.data()[0];
-            tcp_data_->proc_pack_carr_error = readbuf.data()[1];
-
-            // Control. The GNSS-SDR program ends if an error in a TCP packet is detected.
-            if (d_control_id_ != readbuf.data()[2])
-                {
-                    throw "Packet error!";
-                }
+			// Recover the variables received
+    		tcp_data_->proc_pack_code_error = readbuf.data()[1];
+    		tcp_data_->proc_pack_carr_error = readbuf.data()[2];
+    		tcp_data_->proc_pack_carrier_doppler_hz = readbuf.data()[3];
    }

    catch(std::exception& e)
--- a/src/algorithms/tracking/libs/tcp_communication.h
+++ b/src/algorithms/tracking/libs/tcp_communication.h
@ -44,9 +44,9 @@ public:
    tcp_communication();
    ~tcp_communication();

-    int listen_tcp_connection(size_t d_port_);
-    void send_receive_tcp_packet(boost::array<float,7> buf, tcp_packet_data *tcp_data_);
-    void close_tcp_connection(size_t d_port_);
+	int listen_tcp_connection(size_t d_port_, size_t d_port_ch0_);
+	void send_receive_tcp_packet(boost::array<float, 9> buf, tcp_packet_data *tcp_data_);
+	void close_tcp_connection(size_t d_port_);

 private:
    boost::asio::io_service io_service_;
--- a/src/algorithms/tracking/libs/tcp_packet_data.h
+++ b/src/algorithms/tracking/libs/tcp_packet_data.h
@ -39,6 +39,7 @@ public:
    ~tcp_packet_data();
    float proc_pack_code_error;
    float proc_pack_carr_error;
+    float proc_pack_carrier_doppler_hz;
 };

 #endif
--- a/src/core/receiver/control_thread.cc
+++ b/src/core/receiver/control_thread.cc
@ -47,7 +47,7 @@
 using google::LogMessage;

 DEFINE_string(config_file, "../conf/gnss-sdr.conf",
-        "Path to the file containing the configuration parameters");
+		"Path to the file containing the configuration parameters");

 ControlThread::ControlThread()
 {
--- a/Thread/README_gnss_sdr_tcp_connector_parallel_tracking.txt
+++ b/Thread/README_gnss_sdr_tcp_connector_parallel_tracking.txt
@ -0,0 +1,159 @@
+ /*! 
+  * \file README.txt
+  * \brief How to add a block to the Simulink Library repository of Matlab,
+  * how to use the "gnss_sdr_tcp_connector_parallel_tracking_start.m" script
+  * and how to replace the tracking block of the library. Parallel Computing 
+  * version.
+  *
+  * \author David Pubill, 2012. dpubill(at)cttc.es
+  *
+  * -------------------------------------------------------------------------
+  *
+  * Copyright (C) 2010-2012  (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/>.
+  *
+  * -------------------------------------------------------------------------
+  */
+
+
+IMPORTANT: Please, to use this tracking check the configuration file called
+'gnss-sdr_tcp_connector_tracking.conf'. There are two major changes:
+	1.- Choose the [GPS_L1_CA_TCP_CONNECTOR_Tracking] tracking algorithm.
+	2.- Choose a tcp port for channel 0 (e.g. Tracking.port_ch0=2070;) 
+
+
+A) HOW TO add a block to the Simulink Library repository of your Matlab installation
+   ---------------------------------------------------------------------------------
+ (These steps should be followed only the first time)
+
+1.- Copy the content of this folder to a folder accessible from Simulink.
+
+2.- In the Matlab Command Window type:
+	>> simulink;
+    to open the Simulink Library Browser.
+
+3.- Right-click on the Simulink/User-Defined Functions of the Simulink 
+    Library menu, and click on "Open User-Defined Functions library" 
+    (Window_1).
+
+4.- Open the library model 'gnss_sdr_tcp_connector_tracking_lib.mdl'
+    (Window_2)
+
+5.- If this is not the first time there should be an existing 'gnss-sdr' 
+    block in the 'User-Defined Functions' window that should be deleted 
+    before drag and drop the new 'gnss_sdr' block (which includes 3 blocks: 
+        - 'gnss_sdr_tcp_connector_tracking_rx' block
+        - 'gnss_sdr_tcp_connector_tracking' block
+        - 'gnss_sdr_tcp_connector_tracking_tx' block) 
+    from Window_2 to Window_1. A new message should appear: "This library 
+    is locked. The action performed requires it to be unlocked". Then, 
+    click on the "Unlock" button (the block will be copied) and close 
+    Window_2.
+
+6.- Right-click on the 'gnss-sdr' block and click on "Link Options --> 
+    Disable link", repeat the action but now clicking on "Link Options --> 
+    Break link". This action disables and breaks the link with the 
+    original library model.
+
+7.- On Window_1 save the "simulink/User-Defined Functions" library. 
+    To do that go to "File > Save". Then, close Window_1.
+
+8.- From "Simulink Library Browser" window, press F5 to refresh and generate 
+    the new Simulink Library repository (it may take a few seconds). This 
+    completes the installation of the custom Simulink block.
+
+
+B) HOW TO use the "gnss_sdr_tcp_connector_parallel_tracking_start.m" script:
+   ----------------------------------------------------------------
+
+-----------------------     ------------------     -----------------------    
+|                     |     |                |     |                     |    
+| gnss_sdr_tcp_       |     | gnss_sdr_tcp_  |     | gnss_sdr_tcp_       |  
+| connector_tracking_ | --> | connector_     | --> | connector_tracking_ |
+| rx                  |     | tracking       |     | tx                  |     
+|                     |     |                |     |                     |     
+-----------------------     ------------------     -----------------------     
+
+The 'gnss_sdr_tcp_connector_parallel_tracking_start.m' is the script that 
+builds and configures a Simulink model for interacting with the GNSS-SDR 
+platform through a TCP communication. Some 'User parameters' can be 
+modified but, by default, these are the values assigned:
+
+%User parameters 
+    host = '84.88.61.86'; %Remote IP address (GNSS-SDR computer IP)
+    port = 2070;          %Remote port (GNSS-SDR computer port for Ch0)
+    num_vars_rx = 9;      %Number of variables expected from GNSS-SDR
+    num_vars_tx = 4;      %Number of variable to be transmitted to GNSS-SDR
+    timeout = '40';       %Timeout in seconds
+
+'host', 'port' and 'timeout' parameters configure both 
+'gnss_sdr_tcp_connector_tracking_rx' and 'gnss_sdr_tcp_connector_tracking_tx' 
+blocks. The 'port' parameter sets the base port number for the first 
+channel (ch0). Each of the subsequent channels increases their port by one 
+unit (e.g. ch0_port=2070, ch1_port=2071,...).
+
+Also the name of the tracking block can be modified. It must match with 
+the Simulink model name:
+
+    %Name of the tracking block, it must match the Simulink model name
+    tracking_block_name = 'gnss_sdr_tcp_connector_tracking';
+
+To configure the MATLAB to work in parallel mode (the 'Parallel Computing' 
+Toolbox must be installed in the MATLAB) type in the Matlab Command Window 
+the following:
+
+>> matlabpool(C)
+
+where C is the number of cores of the computer to be used.
+
+Then it should appear a message like this one:
+
+"Destroying 1 pre-existing parallel job(s) created by matlabpool that were 
+in the finished or failed state.
+
+Starting matlabpool using the 'local' configuration ... connected to 4 
+labs."
+
+Once the MATLAB is configured to work in parallel mode, type the following 
+to run the script:
+
+>> gnss_sdr_tcp_connector_parallel_tracking_start(N,C);
+
+where N must match the number of channels configured in the GNSS-SDR
+platform and C is the same as before.
+
+Note: to stop working with the parallel mode type in the Command Window 
+the following:
+
+>> matlabpool close
+
+
+C) HOW TO replace the tracking block of the library
+   ------------------------------------------------
+
+1.- Open the library model 'gnss_sdr_tcp_connector_tracking_lib.mdl'
+2.- Unlock the library. Click on "Edit > Unlock Library".
+3.- Open the "gnss-sdr" block and change the "gnss_sdr_tcp_connector_tracking"
+    block by another one. If the name is different it must be updated in
+    the "gnss_sdr_tcp_connector_parallel_tracking_start.m" code (see 
+    section B)
+4.- Save the new library.
+5.- Go to section A and follow the instructions. 
+
--- a/Thread/gnss_sdr_tcp_connector_parallel_tracking_start.m
+++ b/Thread/gnss_sdr_tcp_connector_parallel_tracking_start.m
@ -0,0 +1,201 @@
+% /*! 
+%  * \file gnss_sdr_tcp_connector_tracking_start.m
+%  * \brief This MATLAB function builds and configures a Simulink model 
+%  * for interacting with the GNSS-SDR platform through a TCP
+%  * communication. Parallel Computing version.
+%  * \author David Pubill, 2012. dpubill(at)cttc.es
+%  *
+%  * ----------------------------------------------------------------------
+%  *
+%  * Copyright (C) 2010-2012  (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/>.
+%  *
+%  * ----------------------------------------------------------------------
+%  */
+
+function gnss_sdr_tcp_connector_parallel_tracking_start(num_channels, num_cores)
+    
+    %The parallel for (parfor) loop allows to build and run a Simulink
+    %model in parallel mode, programming different threads
+    parfor i = 0:num_cores-1;
+    
+        %Open and close the Simulink Library
+        simulink('open');
+        simulink('close');
+        
+        %User parameters 
+        host = '84.88.61.86'; %Remote IP address (GNSS-SDR computer IP)
+        port = 2070;          %Remote port (GNSS-SDR computer port for Ch0)
+        num_vars_rx = 9;      %Number of variables expected from GNSS-SDR
+        num_vars_tx = 4;      %Number of variable to be transmitted to GNSS-SDR
+        timeout = '40';       %Timeout [s]
+            
+        %Name of the tracking block, it must match the Simulink model name
+        tracking_block_name = 'gnss_sdr_tcp_connector_tracking';
+    
+        % Layout coordinates for the gnss_sdr_tcp_connector_tracking blocks
+        X0 = 20;
+        X1 = 170;
+        Y0 = 20;
+        Y1 = 140;
+        X_offset = 200;
+        Y_offset = 160;
+    
+        %Calculate the size of the data received from GNSS-SDR 
+        %(float = 4 bytes each variable)
+        datasize_RX = num_vars_rx*4;
+        
+        %Create a Simulink model
+        model_name = ['gnss_sdr_tcp_connector_parallel_tracking_aux_', num2str(i)];
+        new_system(model_name);
+        open_system(model_name);
+                
+        %Set parameters to avoid warnings in the Command Window
+        set_param(model_name,...
+        'InheritedTsInSrcMsg', 'none');
+        warning('off', 'Simulink:Commands:SetParamLinkChangeWarn');
+        
+        %Assign values to the variables used by Simulink in the base workspace
+        assignin('base', 'Ti', 1e-3);
+        assignin('base', 'f0', 1.57542e9);
+        assignin('base', 'SFunSlope', 3.5);
+        assignin('base', 'Tc', 4e-3/4092);
+        assignin('base', 'T', 1e-3);
+        assignin('base', 'B_PLL', 50);
+        assignin('base', 'B_DLL', 2);
+                
+        %Calculate some variables to control the number of blocks that 
+        %should content each Simulink model in function of the number of
+        %cores specified
+        min_num_blocks_per_model = floor(num_channels/num_cores);
+        id = rem(num_channels,num_cores);
+        
+        if(i<id)
+            aux=1;
+        else
+            aux=0;
+        end
+        
+        %Build the Simulink model for the core 'i'
+        for m = 0:min_num_blocks_per_model+aux-1
+        
+            index = m + min_num_blocks_per_model*i + min(id,i);
+            
+            %Add and prepare an empty block to become the TCP connector block
+            tcp_connector_block=[model_name, '/gnss_sdr_tcp_connector_tracking_', num2str(index)]; 
+
+            add_block('simulink/Ports & Subsystems/Subsystem', tcp_connector_block);
+            delete_line(tcp_connector_block, 'In1/1', 'Out1/1')
+
+            tcp_connector_tracking_i_In1 = [model_name,'/gnss_sdr_tcp_connector_tracking_',num2str(index),'/In1'];
+            tcp_connector_tracking_i_Out1 = [model_name,'/gnss_sdr_tcp_connector_tracking_',num2str(index),'/Out1'];
+
+            delete_block(tcp_connector_tracking_i_In1);
+            delete_block(tcp_connector_tracking_i_Out1);
+
+            %Add to the TCP connector block the receiver, the tracking and the
+            %transmitter blocks
+            tcp_connector_tracking_rx_block = [model_name,'/gnss_sdr_tcp_connector_tracking_',num2str(index),'/gnss_sdr_tcp_connector_tracking_rx'];
+            tcp_connector_tracking_block = [model_name,'/gnss_sdr_tcp_connector_tracking_',num2str(index),'/', tracking_block_name];
+            tcp_connector_tracking_tx_block = [model_name,'/gnss_sdr_tcp_connector_tracking_',num2str(index),'/gnss_sdr_tcp_connector_tracking_tx'];
+
+            add_block('simulink/User-Defined Functions/gnss_sdr/gnss_sdr_tcp_connector_tracking_rx',tcp_connector_tracking_rx_block);
+
+            path_to_tracking_block = ['simulink/User-Defined Functions/gnss_sdr/', tracking_block_name];
+            add_block(path_to_tracking_block, tcp_connector_tracking_block);
+
+            add_block('simulink/User-Defined Functions/gnss_sdr/gnss_sdr_tcp_connector_tracking_tx',tcp_connector_tracking_tx_block);
+
+            %Connect the receiver block to the tracking block
+            for j=1:num_vars_rx;
+                rx_out_ports =['gnss_sdr_tcp_connector_tracking_rx/', num2str(j)];
+                tracking_in_ports =[tracking_block_name, '/', num2str(j)];
+
+                add_line(tcp_connector_block, rx_out_ports, tracking_in_ports)
+            end
+
+            %Connect the tracking block to the transmitter block
+            for k=1:num_vars_tx;
+                tracking_out_ports =[tracking_block_name, '/', num2str(k)];
+                tx_in_ports =['gnss_sdr_tcp_connector_tracking_tx/',num2str(k)];
+
+                add_line(tcp_connector_block, tracking_out_ports, tx_in_ports)
+            end
+
+            %Add, place and connect two scopes in the TCP connector block
+            name_scope_1 = [tcp_connector_block,'/Scope'];
+            add_block('simulink/Sinks/Scope', name_scope_1, 'Position', [500 300 550 350]);
+            set_param(name_scope_1, 'NumInputPorts', '4', 'LimitDataPoints', 'off');
+            add_line(tcp_connector_block, 'gnss_sdr_tcp_connector_tracking_rx/9', 'Scope/1', 'autorouting','on')
+
+            tracking_scope_port2 = [tracking_block_name,'/2'];
+            add_line(tcp_connector_block, tracking_scope_port2, 'Scope/2', 'autorouting','on')
+            tracking_scope_port3 = [tracking_block_name,'/3'];
+            add_line(tcp_connector_block, tracking_scope_port3, 'Scope/3', 'autorouting','on')
+            tracking_scope_port4 = [tracking_block_name,'/4'];
+            add_line(tcp_connector_block, tracking_scope_port4, 'Scope/4', 'autorouting','on')
+
+            name_scope_2 = [tcp_connector_block,'/EPL'];
+            add_block('simulink/Sinks/Scope', name_scope_2, 'Position', [500 400 550 450]);
+            set_param(name_scope_2, 'LimitDataPoints', 'off');
+            tracking_scope2_port5 = [tracking_block_name,'/5'];
+            add_line(tcp_connector_block, tracking_scope2_port5, 'EPL/1', 'autorouting','on')
+
+            num_port = port+index;
+
+            %Set the TCP receiver parameters
+            tcp_receiver = [model_name,'/gnss_sdr_tcp_connector_tracking_',num2str(index),'/gnss_sdr_tcp_connector_tracking_rx/RX'];
+            set_param(tcp_receiver, 'Port', num2str(num_port), 'Host', host, 'DataSize', num2str(datasize_RX), 'Timeout', timeout);
+
+            %Set the TCP transmitter parameters
+            tcp_transmitter = [model_name, '/gnss_sdr_tcp_connector_tracking_',num2str(index),'/gnss_sdr_tcp_connector_tracking_tx/TX'];
+            set_param(tcp_transmitter, 'Port', num2str(num_port), 'Host', host,'Timeout', timeout);
+
+            %New layout coordinates for each block
+            X2 = X0 + floor(m/4)*X_offset;
+            X3 = X1 + floor(m/4)*X_offset;
+            Y2 = Y0 + (m-4*floor(m/4))*Y_offset;
+            Y3 = Y1 + (m-4*floor(m/4))*Y_offset;
+            
+            %Place the block in the layout
+            set_param(tcp_connector_block, 'Position', [X2 Y2 X3 Y3]);
+        end
+        
+        %Set parameters to configure the model Solver
+        set_param(model_name,...
+            'SolverType', 'Fixed-step', 'Solver', 'FixedStepDiscrete',...
+            'FixedStep', 'auto', 'StopTime', 'inf');
+            
+        %Save the model with a definitive name
+        model_name_ready = ['gnss_sdr_tcp_connector_parallel_tracking_ready_', num2str(i)]; 
+        save_system(model_name, model_name_ready);
+        
+        %Pause the thread 'i*5' seconds in function of the number of core.
+        %This allows the system to establish the TCP connections in the
+        %correct order
+        if (aux == 0)
+               pause(i*5);
+        end
+               
+        %Run the Simulink model
+        set_param(model_name_ready,'simulationcommand','start');
+                
+    end    
+end
--- a/src/utils/simulink/gnss_sdr_tcp_connector_tracking_lib.mdl
+++ b/src/utils/simulink/gnss_sdr_tcp_connector_tracking_lib.mdl
--- a/src/utils/simulink/README_gnss_sdr_tcp_connector_tracking.txt
+++ b/src/utils/simulink/README_gnss_sdr_tcp_connector_tracking.txt
@ -1,7 +1,8 @@
 /*! 
  * \file README.txt
-  * \brief How to add a block to the Simulink Library repository of Matlab
-  * and how to use the "gnss_sdr_tcp_connector_tracking_start.m" script.
+  * \brief How to add a block to the Simulink Library repository of Matlab,
+  * how to use the "gnss_sdr_tcp_connector_tracking_start.m" script and how
+  * to replace the tracking block of the library.
  *
  * \author David Pubill, 2012. dpubill(at)cttc.es
  *
@ -35,7 +36,7 @@ IMPORTANT: Please, to use this tracking check the configuration file called
 'gnss-sdr_tcp_connector_tracking.conf'. There are two major changes:
 	1.- Choose the [GPS_L1_CA_TCP_CONNECTOR_Tracking] tracking algorithm.
 	2.- Choose a tcp port for channel 0 (e.g. Tracking.port_ch0=2060;) 
-	
+

 A) HOW TO add a block to the Simulink Library repository of your Matlab installation
   ---------------------------------------------------------------------------------
@ -51,19 +52,31 @@ A) HOW TO add a block to the Simulink Library repository of your Matlab installa
    Library menu, and click on "Open User-Defined Functions library" 
    (Window_1)

-4.- Open the library model 'gnss_sdr_tcp_connector_tracking_lib.mdl'(Window_2)
+4.- Open the library model 'gnss_sdr_tcp_connector_tracking_lib.mdl'
+    (Window_2)

-5.- Drag and drop the gnss_sdr_tcp_connector_tracking block from Window_2 
-    to Window_1. A new message should appear: "This library is locked. The 
-    action performed requires it to be unlocked". Then, click on the "Unlock" 
-    button (the block will be copied) and close Window_2.
+5.- If this is not the first time there should be an existing 'gnss-sdr' 
+    block in the 'User-Defined Functions' window that should be deleted 
+    before drag and drop the new 'gnss_sdr' block (which includes 3 blocks: 
+        - 'gnss_sdr_tcp_connector_tracking_rx' block
+        - 'gnss_sdr_tcp_connector_tracking' block
+        - 'gnss_sdr_tcp_connector_tracking_tx' block) 
+    from Window_2 to Window_1. A new message should appear: "This library 
+    is locked. The action performed requires it to be unlocked". Then, 
+    click on the "Unlock" button (the block will be copied) and close 
+    Window_2.

-6.- On Window_1 save the "simulink/User-Defined Functions" library. 
+6.- Right-click on the 'gnss-sdr' block and click on "Link Options --> 
+    Disable link", repeat the action but now clicking on "Link Options --> 
+    Break link". This action disables and breaks the link with the 
+    original library model.
+
+7.- On Window_1 save the "simulink/User-Defined Functions" library. 
    To do that go to "File > Save". Then, close Window_1.

-7.- From "Simulink Library Browser" window, press F5 to refresh and generate 
-    the new Simulink Library repository. This may take a few seconds, and 
-    this finish the installation of the custom Simulink block.
+8.- From "Simulink Library Browser" window, press F5 to refresh and generate 
+    the new Simulink Library repository (it may take a few seconds). This 
+    completes the installation of the custom Simulink block.


 B) HOW TO use the "gnss_sdr_tcp_connector_tracking_start.m" script:
@ -71,9 +84,9 @@ B) HOW TO use the "gnss_sdr_tcp_connector_tracking_start.m" script:

 -----------------------     ------------------     -----------------------    
 |                     |     |                |     |                     |    
-| gnss_sdr_tcp_       |     |                |     | gnss_sdr_tcp_       |  
-| connector_tracking_ | --> |      Core      | --> | connector_tracking_ |
-| receive             |     |                |     | send                |     
+| gnss_sdr_tcp_       |     | gnss_sdr_tcp_  |     | gnss_sdr_tcp_       |  
+| connector_tracking_ | --> | connector_     | --> | connector_tracking_ |
+| rx                  |     | tracking       |     | tx                  |     
 |                     |     |                |     |                     |     
 -----------------------     ------------------     -----------------------     

@ -81,22 +94,25 @@ The 'gnss_sdr_tcp_connector_tracking_start.m' is the script that builds and
 configures a simulink model for interacting with the GNSS-SDR platform 
 through a TCP communication. 'User parameters' can be modified but, by 
 default, these are the values assigned:
- 
+
 %User parameters 
-    host = '84.88.61.86'; //Remote IP address (GNSS-SDR computer IP)
-    port = 2060;          //Remote port (GNSS-SDR computer port for Ch0)
-    datasize_RX = '28';   //Data size
-    timeout = '10';       //Timeout in seconds
+    host = '84.88.61.86'; %Remote IP address (GNSS-SDR computer IP)
+    port = 2070;          %Remote port (GNSS-SDR computer port for Ch0)
+    num_vars_rx = 9;      %Number of variables expected from GNSS-SDR
+    num_vars_tx = 4;      %Number of variable to be transmitted to GNSS-SDR
+    timeout = '40';       %Timeout in seconds

-'host', 'port' and 'timeout' parameters configure both 'gnss_sdr_tcp_connector_tracking_receive'
-and 'gnss_sdr_tcp_connector_tracking_send' blocks. The 'port' parameter 
-sets the base port number for the first channel (ch0). Each of the 
-subsequent channels increases their port by one unit (e.g. ch0_port=2060, 
-ch1_port=2061,...)
+'host', 'port' and 'timeout' parameters configure both 
+'gnss_sdr_tcp_connector_tracking_rx' and 'gnss_sdr_tcp_connector_tracking_tx' 
+blocks. The 'port' parameter sets the base port number for the first 
+channel (ch0). Each of the subsequent channels increases their port by one 
+unit (e.g. ch0_port=2070, ch1_port=2071,...).

-'datasize_RX' is the size (in bytes) of the received TCP packet data field. 
-For example, if the number of float (4 bytes) variables to be received from 
-the the GNSS-SDR computer is 7, this parameter must be set to 7*4=28.
+Also the name of the tracking block can be modified. It must match with 
+the Simulink model name:
+
+    %Name of the tracking block, it must match the Simulink model name
+    tracking_block_name = 'gnss_sdr_tcp_connector_tracking';

 To run the script just type in the Matlab Command window the following:

@ -106,8 +122,15 @@ where N must match the number of channels configured in the GNSS-SDR
 platform.


+C) HOW TO replace the tracking block of the library
+   ------------------------------------------------

-
-
-
+1.- Open the library model 'gnss_sdr_tcp_connector_tracking_lib.mdl'
+2.- Unlock the library. Click on "Edit > Unlock Library".
+3.- Open the "gnss-sdr" block and change the "gnss_sdr_tcp_connector_tracking"
+    block by another one. If the name is different it must be updated in
+    the "gnss_sdr_tcp_connector_parallel_tracking_start.m" code (see 
+    section B)
+4.- Save the new library.
+5.- Go to section A and follow the instructions. 

--- a/Thread/gnss_sdr_tcp_connector_tracking_lib.mdl
+++ b/Thread/gnss_sdr_tcp_connector_tracking_lib.mdl
--- a/Thread/gnss_sdr_tcp_connector_tracking_start.m
+++ b/Thread/gnss_sdr_tcp_connector_tracking_start.m
@ -0,0 +1,170 @@
+% /*! 
+%  * \file gnss_sdr_tcp_connector_tracking_start.m
+%  * \brief This MATLAB function builds and configures a simulink model 
+%  * for interacting with the GNSS-SDR platform through a TCP communication.
+%  * \author David Pubill, 2012. dpubill(at)cttc.es
+%  *
+%  * ----------------------------------------------------------------------
+%  *
+%  * Copyright (C) 2010-2012  (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/>.
+%  *
+%  * ----------------------------------------------------------------------
+%  */
+
+function gnss_sdr_tcp_connector_tracking_start(num_channels)
+    
+    %User parameters 
+    host = '84.88.61.86'; %Remote IP address (GNSS-SDR computer IP)
+    port = 2070;          %Remote port (GNSS-SDR computer port for Ch0)
+    num_vars_rx = 9;      %Number of variables expected from GNSS-SDR
+    num_vars_tx = 4;      %Number of variable to be transmitted to GNSS-SDR
+    timeout = '40';       %Timeout [s]
+    
+    %name of the tracking block, it must match the name of the Simulink
+    %model
+    tracking_block_name = 'gnss_sdr_tcp_connector_tracking';
+    
+    % Layout coordinates for the first gnss_sdr_tcp_connector_tracking
+    % block and offset definitions
+    X0 = 20;
+    X1 = 170;
+    Y0 = 20;
+    Y1 = 140;
+    X_offset = 200;
+    Y_offset = 160;
+    
+    %Calculate the size of the data received from GNSS-SDR 
+    %(float = 4 bytes each variable)
+    datasize_RX = num_vars_rx*4;
+    
+    %Create a Simulink model
+    simulink('open');
+    new_system('gnss_sdr_tcp_connector_tracking_aux');
+    open_system('gnss_sdr_tcp_connector_tracking_aux');
+    
+    %Set parameters to avoid warnings in the Command Window
+    set_param('gnss_sdr_tcp_connector_tracking_aux',...
+        'InheritedTsInSrcMsg', 'none');
+    warning('off', 'Simulink:Commands:SetParamLinkChangeWarn');
+    
+    %Assign values to the variables used by Simulink in the base workspace
+    assignin('base', 'Ti', 1e-3);
+    assignin('base', 'f0', 1.57542e9);
+    assignin('base', 'SFunSlope', 3.5);
+    assignin('base', 'Tc', 4e-3/4092);
+    assignin('base', 'T', 1e-3);
+    assignin('base', 'B_PLL', 50);
+    assignin('base', 'B_DLL', 2);
+    
+    %Block generation from the Simulink Library
+    for i = 0:num_channels-1;
+           
+        %Add and prepare an empty block to become the TCP connector block
+        tcp_connector_block=['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_', num2str(i)]; 
+        
+        add_block('simulink/Ports & Subsystems/Subsystem', tcp_connector_block);
+        delete_line(tcp_connector_block,'In1/1', 'Out1/1')
+        
+        tcp_connector_tracking_i_In1 = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/In1'];
+        tcp_connector_tracking_i_Out1 = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/Out1'];
+        
+        delete_block(tcp_connector_tracking_i_In1);
+        delete_block(tcp_connector_tracking_i_Out1);
+       
+        %Add to the TCP connector block the receiver, the tracking and the
+        %transmitter blocks
+        tcp_connector_tracking_rx_block = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/gnss_sdr_tcp_connector_tracking_rx'];
+        tcp_connector_tracking_block = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/',tracking_block_name];
+        tcp_connector_tracking_tx_block = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/gnss_sdr_tcp_connector_tracking_tx'];
+        
+        add_block('simulink/User-Defined Functions/gnss_sdr/gnss_sdr_tcp_connector_tracking_rx',tcp_connector_tracking_rx_block);
+        
+        path_to_tracking_block = ['simulink/User-Defined Functions/gnss_sdr/', tracking_block_name];
+        add_block(path_to_tracking_block, tcp_connector_tracking_block);
+        
+        add_block('simulink/User-Defined Functions/gnss_sdr/gnss_sdr_tcp_connector_tracking_tx',tcp_connector_tracking_tx_block);
+                
+        %Connect the receiver block to the tracking block
+        for j=1:num_vars_rx;
+            rx_out_ports =['gnss_sdr_tcp_connector_tracking_rx/',num2str(j)];
+            tracking_in_ports =[tracking_block_name,'/',num2str(j)];
+            
+            add_line(tcp_connector_block, rx_out_ports, tracking_in_ports)
+        end
+        
+        %Connect the tracking block to the transmitter block
+        for k=1:num_vars_tx;
+            tracking_out_ports =[tracking_block_name,'/',num2str(k)];
+            tx_in_ports =['gnss_sdr_tcp_connector_tracking_tx/',num2str(k)];
+            
+            add_line(tcp_connector_block, tracking_out_ports, tx_in_ports)
+        end
+        
+        %Add, place and connect two scopes in the TCP connector block
+        name_scope_1 = [tcp_connector_block,'/Scope'];
+        add_block('simulink/Sinks/Scope', name_scope_1, 'Position', [500 300 550 350]);
+        set_param(name_scope_1, 'NumInputPorts', '4', 'LimitDataPoints', 'off');
+        add_line(tcp_connector_block, 'gnss_sdr_tcp_connector_tracking_rx/9', 'Scope/1', 'autorouting','on')
+        
+        tracking_scope_port2 = [tracking_block_name,'/2'];
+        add_line(tcp_connector_block, tracking_scope_port2, 'Scope/2', 'autorouting','on')
+        tracking_scope_port3 = [tracking_block_name,'/3'];
+        add_line(tcp_connector_block, tracking_scope_port3, 'Scope/3', 'autorouting','on')
+        tracking_scope_port4 = [tracking_block_name,'/4'];
+        add_line(tcp_connector_block, tracking_scope_port4, 'Scope/4', 'autorouting','on')
+        
+        name_scope_2 = [tcp_connector_block,'/EPL'];
+        add_block('simulink/Sinks/Scope', name_scope_2, 'Position', [500 400 550 450]);
+        set_param(name_scope_2, 'LimitDataPoints', 'off');
+        tracking_scope2_port5 = [tracking_block_name,'/5'];
+        add_line(tcp_connector_block, tracking_scope2_port5, 'EPL/1', 'autorouting','on')
+        
+        %Set the TCP receiver parameters
+        tcp_receiver = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/gnss_sdr_tcp_connector_tracking_rx/RX'];
+        set_param(tcp_receiver, 'Port', num2str(port+i), 'Host', host, 'DataSize', num2str(datasize_RX), 'Timeout', timeout);
+        
+        %Set the TCP transmitter parameters
+        tcp_transmitter = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',num2str(i),'/gnss_sdr_tcp_connector_tracking_tx/TX'];
+        set_param(tcp_transmitter, 'Port', num2str(port+i), 'Host', host,'Timeout', timeout);
+
+        %New layout coordinates for each block
+        X2 = X0 + floor(i/4)*X_offset;
+        X3 = X1 + floor(i/4)*X_offset;
+        Y2 = Y0 + (i-4*floor(i/4))*Y_offset;
+        Y3 = Y1 + (i-4*floor(i/4))*Y_offset;
+
+        %Place the block in the layout
+        set_param(tcp_connector_block, 'Position', [X2 Y2 X3 Y3]);
+    end
+    
+    %Set parameters to configure the model Solver
+    set_param('gnss_sdr_tcp_connector_tracking_aux',...
+        'SolverType', 'Fixed-step', 'Solver', 'FixedStepDiscrete',...
+        'FixedStep', 'auto', 'StopTime', 'inf');
+    
+    %Save the model with a definitive name
+    save_system('gnss_sdr_tcp_connector_tracking_aux', 'gnss_sdr_tcp_connector_tracking_ready');
+    simulink('close');
+    
+    %Run the Simulink model
+    set_param('gnss_sdr_tcp_connector_tracking_ready','simulationcommand','start');
+    
+end
--- a/src/utils/simulink/gnss_sdr_tcp_connector_tracking_start.m
+++ b/src/utils/simulink/gnss_sdr_tcp_connector_tracking_start.m
@ -1,100 +0,0 @@
-% /*! 
-%  * \file gnss_sdr_tcp_connector_tracking_start.m
-%  * \brief This MATLAB function builds and configures a simulink model 
-%  * for interacting with the GNSS-SDR platform through a TCP communication.
-%  * \author David Pubill, 2012. dpubill(at)cttc.es
-%  *
-%  * ----------------------------------------------------------------------
-%  *
-%  * Copyright (C) 2010-2012  (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/>.
-%  *
-%  * ----------------------------------------------------------------------
-%  */
-
-function gnss_sdr_tcp_connector_tracking_start(num_channels)
-    
-    %User parameters 
-    host = '84.88.61.86'; %Remote IP address (GNSS-SDR computer IP)
-    port = 2060;          %Remote port (GNSS-SDR computer port for Ch0)
-    datasize_RX = '28';   %Data size
-    timeout = '10';       %Timeout in seconds
-    
-    % Layout coordinates for the first gnss_sdr_tcp_connector_tracking
-    % block and offset definitions
-    X0 = 20;
-    X1 = 170;
-    Y0 = 20;
-    Y1 = 140;
-    X_offset = 200;
-    Y_offset = 160;
-    
-    %Create a Simulink model
-    simulink('open');
-    new_system('gnss_sdr_tcp_connector_tracking_aux');
-    open_system('gnss_sdr_tcp_connector_tracking_aux');
-    
-    %Set parameters to configure the model Solver
-    set_param('gnss_sdr_tcp_connector_tracking_aux',...
-        'SolverType', 'Fixed-step', 'Solver', 'FixedStepDiscrete',...
-        'FixedStep', '100', 'StopTime', 'inf');
-    
-    %Set parameters to avoid warnings in the Command Window
-    set_param('gnss_sdr_tcp_connector_tracking_aux',...
-        'InheritedTsInSrcMsg', 'none');
-    warning('off', 'Simulink:Commands:SetParamLinkChangeWarn');
-    
-    %Block generation from the Simulink Library
-    for i=0:num_channels-1;
-        
-        name_new_block=['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',...
-            num2str(i)]; 
-        
-        add_block('simulink/User-Defined Functions/gnss_sdr_tcp_connector_tracking',...
-            name_new_block);
-                
-        name_RX = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',...
-            num2str(i),'/gnss_sdr_tcp_connector_tracking_receive'];
-        
-        set_param(name_RX, 'Port', num2str(port+i), 'Host', host,...
-            'DataSize', datasize_RX, 'Timeout', timeout);
-               
-        name_TX = ['gnss_sdr_tcp_connector_tracking_aux/gnss_sdr_tcp_connector_tracking_',...
-            num2str(i),'/gnss_sdr_tcp_connector_tracking_send'];
-        
-        set_param(name_TX, 'Port', num2str(port+i), 'Host', host,...
-            'Timeout', timeout);
-
-        %New layout coordinates for each block
-        X2 = X0 + floor(i/4)*X_offset;
-        X3 = X1 + floor(i/4)*X_offset;
-        Y2 = Y0 + (i-4*floor(i/4))*Y_offset;
-        Y3 = Y1 + (i-4*floor(i/4))*Y_offset;
-
-        set_param(name_new_block, 'Position', [X2 Y2 X3 Y3]);
-    end
-    
-    save_system('gnss_sdr_tcp_connector_tracking_aux', 'gnss_sdr_tcp_connector_tracking_ready');
-    simulink('close');
-    
-    %Start Simulink simulation
-    set_param('gnss_sdr_tcp_connector_tracking_ready','simulationcommand','start');
-    
-end