Merge branch 'contrib' of https://github.com/odrisci/gnss-sdr into

odrisci-contrib

# Conflicts:
#	src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_tracking_cc.cc
#	src/algorithms/tracking/libs/tracking_discriminators.cc

CMakeLists.txt

@@ -364,6 +364,9 @@ if(NOT GNURADIO_RUNTIME_FOUND)
        message("You can install it easily via Macports.")
        message("Open a terminal and type:")
        message("sudo port install gnuradio ")
+       message("Alternatively you can use homebrew.")
+       message("brew tap odrisci/gnuradio")
+       message("brew install gnuradio" )
        message(FATAL_ERROR "GNU Radio 3.7.3 or later is required to build gnss-sdr")
    endif(OS_IS_MACOSX)
 endif(NOT GNURADIO_RUNTIME_FOUND)

README.md

@@ -390,7 +390,11 @@ Agree to Xcode license:
 $ sudo xcodebuild -license
 ~~~~~~ 
 
-Then, you need a package manager. For example, you can [install Macports](http://www.macports.org/install.php "Macports"). If you are upgrading from a previous installation, please follow the [migration rules](http://trac.macports.org/wiki/Migration).
+Software pre-requisites can be installed using either [Macports](#macports) or [Homebrew](#homebrew).
+
+####<a name"macports">Macports</a>
+
+First, [install Macports](http://www.macports.org/install.php). If you are upgrading from a previous installation, please follow the [migration rules](http://trac.macports.org/wiki/Migration).
 
 In a terminal, type:
 
@@ -416,12 +420,43 @@ and you can activate a certain version (2.7 works well) by typing:
 $ sudo port select --set python python27
 ~~~~~~ 
 
+#### <a name="homebrew">Homebrew</a>
+
+Instructions for installing gnuradio using [homebrew](http://www.brew.sh) can be found [here](http://github.com/odrisci/homebrew-gnuradio) - please ensure to install all dependencies as required.
+
+Install Armadillo and dependencies:
+
+~~~~~~
+$ brew tap homebrew/science
+$ brew install cmake hdf5 arpack superlu
+$ brew install armadillo
+$ brew install glog gflags
+~~~~~~
+
+#### Build GNSS-SDR
+
 Finally, you are ready to clone the GNSS-SDR repository and build the software:
 
 ~~~~~~ 
 $ git clone https://github.com/gnss-sdr/gnss-sdr
 $ cd gnss-sdr/build
+~~~~~~
+
+If using Macports, run:
+
+~~~~~~
+$ cmake -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DCMAKE_PREFIX_PATH=/opt/local -DUSE_MACPORTS_PYTHON=/opt/local/bin/python ../
+~~~~~~
+
+If using homebrew, run:
+
+~~~~~~
 $ cmake ../
+~~~~~~
+
+Finally, run:
+
+~~~~~~
 $ make
 ~~~~~~ 
 
@@ -431,7 +466,7 @@ This will create three executables at gnss-sdr/install, namely ```gnss-sdr```, `
 $ sudo make install
 ~~~~~~ 
 
-
+Note, it is advisable not to run the install step in a homebrew environment.
 
 The documentation can be built by:
 

src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc

@@ -97,6 +97,10 @@ GalileoE1PcpsAmbiguousAcquisition::GalileoE1PcpsAmbiguousAcquisition(
 
     vector_length_ = sampled_ms_ * samples_per_ms;
 
+    if( bit_transition_flag_ ){
+        vector_length_ *= 2;
+    }
+
     code_ = new gr_complex[vector_length_];
 
     if (item_type_.compare("gr_complex") == 0)

src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition_cc.cc

@@ -40,6 +40,7 @@
 #include <volk/volk.h>
 #include "gnss_signal_processing.h"
 #include "control_message_factory.h"
+#include <boost/filesystem.hpp>
 
 using google::LogMessage;
 
@@ -65,8 +66,8 @@ pcps_acquisition_cc::pcps_acquisition_cc(
                          gr::msg_queue::sptr queue, bool dump,
                          std::string dump_filename) :
     gr::block("pcps_acquisition_cc",
-    gr::io_signature::make(1, 1, sizeof(gr_complex) * sampled_ms * samples_per_ms),
+    gr::io_signature::make(1, 1, sizeof(gr_complex) * sampled_ms * samples_per_ms * ( bit_transition_flag ? 2 : 1 )),
-    gr::io_signature::make(0, 0, sizeof(gr_complex) * sampled_ms * samples_per_ms))
+    gr::io_signature::make(0, 0, sizeof(gr_complex) * sampled_ms * samples_per_ms * ( bit_transition_flag ? 2 : 1 )) )
 {
     d_sample_counter = 0;    // SAMPLE COUNTER
     d_active = false;
@@ -92,6 +93,24 @@ pcps_acquisition_cc::pcps_acquisition_cc(
     d_channel = 0;
     d_doppler_freq = 0.0;
 
+    //set_relative_rate( 1.0/d_fft_size );
+
+    // COD:
+    // Experimenting with the overlap/save technique for handling bit trannsitions
+    // The problem: Circular correlation is asynchronous with the received code.
+    // In effect the first code phase used in the correlation is the current
+    // estimate of the code phase at the start of the input buffer. If this is 1/2
+    // of the code period a bit transition would move all the signal energy into
+    // adjacent frequency bands at +/- 1/T where T is the integration time.
+    //
+    // We can avoid this by doing linear correlation, effectively doubling the
+    // size of the input buffer and padding the code with zeros.
+    if( d_bit_transition_flag )
+    {
+        d_fft_size *= 2;
+        d_max_dwells = 1;
+    }
+
     d_fft_codes = static_cast<gr_complex*>(volk_malloc(d_fft_size * sizeof(gr_complex), volk_get_alignment()));
     d_magnitude = static_cast<float*>(volk_malloc(d_fft_size * sizeof(float), volk_get_alignment()));
 
@@ -135,7 +154,17 @@ pcps_acquisition_cc::~pcps_acquisition_cc()
 
 void pcps_acquisition_cc::set_local_code(std::complex<float> * code)
 {
-    memcpy(d_fft_if->get_inbuf(), code, sizeof(gr_complex) * d_fft_size);
+    // COD
+    // Here we want to create a buffer that looks like this:
+    // [ 0 0 0 ... 0 c_0 c_1 ... c_L]
+    // where c_i is the local code and there are L zeros and L chips
+    int offset = 0;
+    if( d_bit_transition_flag )
+    {
+        std::fill_n( d_fft_if->get_inbuf(), d_samples_per_code, gr_complex( 0.0, 0.0 ) );
+        offset = d_samples_per_code;
+    }
+    memcpy(d_fft_if->get_inbuf() + offset, code, sizeof(gr_complex) * d_samples_per_code);
     d_fft_if->execute(); // We need the FFT of local code
     volk_32fc_conjugate_32fc(d_fft_codes, d_fft_if->get_outbuf(), d_fft_size);
 }
@@ -157,7 +186,7 @@ void pcps_acquisition_cc::init()
         {
             d_grid_doppler_wipeoffs[doppler_index] = static_cast<gr_complex*>(volk_malloc(d_fft_size * sizeof(gr_complex), volk_get_alignment()));
             int doppler = -static_cast<int>(d_doppler_max) + d_doppler_step * doppler_index;
-            complex_exp_gen(d_grid_doppler_wipeoffs[doppler_index], d_freq - doppler, d_fs_in, d_fft_size);
+            complex_exp_gen(d_grid_doppler_wipeoffs[doppler_index], -d_freq - doppler, d_fs_in, d_fft_size);
         }
 }
 
@@ -222,6 +251,8 @@ int pcps_acquisition_cc::general_work(int noutput_items,
             d_sample_counter += d_fft_size * ninput_items[0]; // sample counter
             consume_each(ninput_items[0]);
 
+            //DLOG(INFO) << "Consumed " << ninput_items[0] << " items";
+
             break;
         }
 
@@ -232,7 +263,13 @@ int pcps_acquisition_cc::general_work(int noutput_items,
             unsigned int indext = 0;
             float magt = 0.0;
             const gr_complex *in = (const gr_complex *)input_items[0]; //Get the input samples pointer
-            float fft_normalization_factor = static_cast<float>(d_fft_size) * static_cast<float>(d_fft_size);
+
+            int effective_fft_size = ( d_bit_transition_flag ? d_fft_size/2 : d_fft_size );
+            size_t offset = ( d_bit_transition_flag ? effective_fft_size : 0 );
+
+            float fft_normalization_factor = static_cast<float>(d_fft_size)
+                * static_cast<float>(d_fft_size);
+
             d_input_power = 0.0;
             d_mag = 0.0;
 
@@ -273,8 +310,9 @@ int pcps_acquisition_cc::general_work(int noutput_items,
                     d_ifft->execute();
 
                     // Search maximum
-                    volk_32fc_magnitude_squared_32f(d_magnitude, d_ifft->get_outbuf(), d_fft_size);
+                    size_t offset = ( d_bit_transition_flag ? effective_fft_size : 0 );
-                    volk_32f_index_max_16u(&indext, d_magnitude, d_fft_size);
+                    volk_32fc_magnitude_squared_32f(d_magnitude, d_ifft->get_outbuf() + offset, effective_fft_size);
+                    volk_32f_index_max_16u(&indext, d_magnitude, effective_fft_size);
 
                     // Normalize the maximum value to correct the scale factor introduced by FFTW
                     magt = d_magnitude[indext] / (fft_normalization_factor * fft_normalization_factor);
@@ -309,9 +347,19 @@ int pcps_acquisition_cc::general_work(int noutput_items,
                             std::stringstream filename;
                             std::streamsize n = 2 * sizeof(float) * (d_fft_size); // complex file write
                             filename.str("");
-                            filename << "../data/test_statistics_" << d_gnss_synchro->System
+
+                            boost::filesystem::path p = d_dump_filename;
+                            filename << p.parent_path().string()
+                                     << boost::filesystem::path::preferred_separator
+                                     << p.stem().string()
+                                     << "_" << d_gnss_synchro->System
                                      <<"_" << d_gnss_synchro->Signal << "_sat_"
-                                     << d_gnss_synchro->PRN << "_doppler_" <<  doppler << ".dat";
+                                     << d_gnss_synchro->PRN << "_doppler_"
+                                     <<  doppler
+                                     << p.extension().string();
+
+                            DLOG(INFO) << "Writing ACQ out to " << filename.str();
+
                             d_dump_file.open(filename.str().c_str(), std::ios::out | std::ios::binary);
                             d_dump_file.write((char*)d_ifft->get_outbuf(), n); //write directly |abs(x)|^2 in this Doppler bin?
                             d_dump_file.close();
@@ -346,6 +394,8 @@ int pcps_acquisition_cc::general_work(int noutput_items,
 
             consume_each(1);
 
+            DLOG(INFO) << "Done. Consumed 1 item.";
+
             break;
         }
 
@@ -402,3 +452,18 @@ int pcps_acquisition_cc::general_work(int noutput_items,
 
     return noutput_items;
 }
+
+
+//void pcps_acquisition_cc::forecast (int noutput_items, gr_vector_int &ninput_items_required)
+//{
+    //// COD:
+    //// For zero-padded case we need one extra code period
+    //if( d_bit_transition_flag )
+    //{
+        //ninput_items_required[0] = noutput_items*(d_samples_per_code * d_max_dwells + d_samples_per_code);
+    //}
+    //else
+    //{
+        //ninput_items_required[0] = noutput_items*d_fft_size*d_max_dwells;
+    //}
+//}

src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition_fine_doppler_cc.cc

@@ -201,7 +201,7 @@ void pcps_acquisition_fine_doppler_cc::update_carrier_wipeoff()
             doppler_hz = d_config_doppler_min + d_doppler_step*doppler_index;
             // doppler search steps
             // compute the carrier doppler wipe-off signal and store it
-            phase_step_rad = static_cast<float>(GPS_TWO_PI) * doppler_hz / static_cast<float>(d_fs_in);
+            phase_step_rad = static_cast<float>(GPS_TWO_PI) * ( d_freq + doppler_hz ) / static_cast<float>(d_fs_in);
             d_grid_doppler_wipeoffs[doppler_index] = new gr_complex[d_fft_size];
             fxp_nco(d_grid_doppler_wipeoffs[doppler_index], d_fft_size,0, phase_step_rad);
         }
@@ -316,7 +316,7 @@ int pcps_acquisition_fine_doppler_cc::estimate_Doppler(gr_vector_const_void_star
 {
 
     // Direct FFT
-    int zero_padding_factor = 16;
+    int zero_padding_factor = 2;
     int fft_size_extended = d_fft_size * zero_padding_factor;
     gr::fft::fft_complex *fft_operator = new gr::fft::fft_complex(fft_size_extended, true);
 

src/algorithms/signal_source/adapters/file_signal_source.cc

@@ -58,6 +58,8 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
     std::string default_item_type = "short";
     std::string default_dump_filename = "./my_capture.dat";
 
+    double default_seconds_to_skip = 0.0;
+    size_t header_size = 0;
     samples_ = configuration->property(role + ".samples", 0);
     sampling_frequency_ = configuration->property(role + ".sampling_frequency", 0);
     filename_ = configuration->property(role + ".filename", default_filename);
@@ -72,6 +74,11 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
     enable_throttle_control_ = configuration->property(role + ".enable_throttle_control", false);
     std::string s = "InputFilter";
     //double IF = configuration->property(s + ".IF", 0.0);
+    double seconds_to_skip = configuration->property(role + ".seconds_to_skip", default_seconds_to_skip );
+    header_size = configuration->property( role + ".header_size", 0 );
+    long samples_to_skip = 0;
+
+    bool is_complex = false;
 
     if (item_type_.compare("gr_complex") == 0)
         {
@@ -88,6 +95,7 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
     else if (item_type_.compare("ishort") == 0)
         {
             item_size_ = sizeof(int16_t);
+            is_complex = true;
         }
     else if (item_type_.compare("byte") == 0)
         {
@@ -96,6 +104,7 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
     else if (item_type_.compare("ibyte") == 0)
         {
     		item_size_ = sizeof(int8_t);
+            is_complex = true;
         }
     else
         {
@@ -107,6 +116,30 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
     {
             file_source_ = gr::blocks::file_source::make(item_size_, filename_.c_str(), repeat_);
 
+            if( seconds_to_skip > 0 )
+            {
+                samples_to_skip = static_cast< long >(
+                        seconds_to_skip * sampling_frequency_ );
+
+                if( is_complex )
+                {
+                    samples_to_skip *= 2;
+                }
+            }
+            if( header_size > 0 )
+            {
+                samples_to_skip += header_size;
+            }
+
+            if( samples_to_skip > 0 )
+            {
+                LOG(INFO) << "Skipping " << samples_to_skip << " samples of the input file";
+                if( not file_source_->seek( samples_to_skip, SEEK_SET ) )
+                {
+                    LOG(INFO) << "Error skipping bytes!";
+                }
+            }
+
     }
     catch (const std::exception &e)
     {
@@ -174,7 +207,9 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
 
             if (size > 0)
                 {
-                    samples_ = floor(static_cast<double>(size) / static_cast<double>(item_size()) - ceil(0.002 * static_cast<double>(sampling_frequency_))); //process all the samples available in the file excluding at least the last 1 ms
+                    long bytes_to_skip = samples_to_skip*item_size_;
+                    long bytes_to_process = static_cast<long>(size) - bytes_to_skip;
+                    samples_ = floor(static_cast<double>(bytes_to_process) / static_cast<double>(item_size()) - ceil(0.002 * static_cast<double>(sampling_frequency_))); //process all the samples available in the file excluding at least the last 1 ms
                 }
         }
 
@@ -182,10 +217,11 @@ FileSignalSource::FileSignalSource(ConfigurationInterface* configuration,
     double signal_duration_s;
     signal_duration_s = static_cast<double>(samples_) * ( 1 / static_cast<double>(sampling_frequency_));
 
-    if ((item_type_.compare("gr_complex") != 0) || (item_type_.compare("ishort") != 0) || (item_type_.compare("ibyte") != 0) )  // signal is complex (interleaved)
+    if( is_complex )
     {
-            signal_duration_s /= 2;
+        signal_duration_s /= 2.0;
     }
+
     DLOG(INFO) << "Total number samples to be processed= " << samples_ << " GNSS signal duration= " << signal_duration_s << " [s]";
     std::cout << "GNSS signal recorded time to be processed: " << signal_duration_s << " [s]" << std::endl;
 

src/algorithms/tracking/gnuradio_blocks/galileo_e1_dll_pll_veml_tracking_cc.cc

@@ -210,10 +210,10 @@ void galileo_e1_dll_pll_veml_tracking_cc::start_tracking()
 
     d_carrier_lock_fail_counter = 0;
     d_rem_code_phase_samples = 0.0;
-    d_rem_carr_phase_rad = 0;
+    d_rem_carr_phase_rad = 0.0;
-    d_acc_carrier_phase_rad = 0;
+    d_acc_carrier_phase_rad = 0.0;
 
-    d_acc_code_phase_secs = 0;
+    d_acc_code_phase_secs = 0.0;
     d_carrier_doppler_hz = d_acq_carrier_doppler_hz;
     d_current_prn_length_samples = d_vector_length;
 
@@ -249,17 +249,17 @@ void galileo_e1_dll_pll_veml_tracking_cc::update_local_code()
     code_phase_step_chips = d_code_freq_chips / (static_cast<double>(d_fs_in));
     code_phase_step_half_chips = (2.0 * d_code_freq_chips) / (static_cast<double>(d_fs_in));
 
-    rem_code_phase_half_chips = d_rem_code_phase_samples * (2*d_code_freq_chips / d_fs_in);
+    rem_code_phase_half_chips = d_rem_code_phase_samples * (2.0 * d_code_freq_chips / static_cast<double>(d_fs_in));
     tcode_half_chips = - rem_code_phase_half_chips;
 
-    early_late_spc_samples = round(d_early_late_spc_chips / code_phase_step_chips);
+    early_late_spc_samples = std::round(d_early_late_spc_chips / code_phase_step_chips);
-    very_early_late_spc_samples = round(d_very_early_late_spc_chips / code_phase_step_chips);
+    very_early_late_spc_samples = std::round(d_very_early_late_spc_chips / code_phase_step_chips);
 
     epl_loop_length_samples = d_current_prn_length_samples + very_early_late_spc_samples * 2;
 
     for (int i = 0; i < epl_loop_length_samples; i++)
         {
-            associated_chip_index = 2 + round(fmod(tcode_half_chips - 2 * d_very_early_late_spc_chips, code_length_half_chips));
+            associated_chip_index = 2 + std::round(std::fmod(tcode_half_chips - 2.0 * d_very_early_late_spc_chips, static_cast<double>(code_length_half_chips)));
             d_very_early_code[i] = d_ca_code[associated_chip_index];
             tcode_half_chips = tcode_half_chips + code_phase_step_half_chips;
         }
@@ -273,7 +273,7 @@ void galileo_e1_dll_pll_veml_tracking_cc::update_local_code()
 void galileo_e1_dll_pll_veml_tracking_cc::update_local_carrier()
 {
     float sin_f, cos_f;
-    float phase_step_rad = static_cast<float>(2 * GALILEO_PI) * d_carrier_doppler_hz / static_cast<float>(d_fs_in);
+    float phase_step_rad = static_cast<float>(2.0 * GALILEO_PI) * d_carrier_doppler_hz / static_cast<float>(d_fs_in);
     int phase_step_rad_i = gr::fxpt::float_to_fixed(phase_step_rad);
     int phase_rad_i = gr::fxpt::float_to_fixed(d_rem_carr_phase_rad);
 
@@ -315,7 +315,6 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
     double code_error_chips = 0.0;
     double code_error_filt_chips = 0.0;
 
-
     if (d_enable_tracking == true)
         {
             if (d_pull_in == true)
@@ -327,8 +326,8 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
                     double acq_trk_shif_correction_samples;
                     int acq_to_trk_delay_samples;
                     acq_to_trk_delay_samples = d_sample_counter - d_acq_sample_stamp;
-                    acq_trk_shif_correction_samples = d_current_prn_length_samples - fmod(static_cast<float>(acq_to_trk_delay_samples), static_cast<float>(d_current_prn_length_samples));
+                    acq_trk_shif_correction_samples = static_cast<double>(d_current_prn_length_samples) - static_cast<double>(std::fmod(static_cast<double>(acq_to_trk_delay_samples), static_cast<double>(d_current_prn_length_samples)));
-                    samples_offset = round(d_acq_code_phase_samples + acq_trk_shif_correction_samples);
+                    samples_offset = static_cast<int>(std::round(d_acq_code_phase_samples + acq_trk_shif_correction_samples));
                     d_sample_counter = d_sample_counter + samples_offset; //count for the processed samples
                     d_pull_in = false;
                     consume_each(samples_offset); //shift input to perform alignment with local replica
@@ -365,7 +364,7 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
 
             // ################## PLL ##########################################################
             // PLL discriminator
-            carr_error_hz = pll_cloop_two_quadrant_atan(*d_Prompt) / static_cast<float>(GPS_TWO_PI);
+            carr_error_hz = pll_cloop_two_quadrant_atan(*d_Prompt) / static_cast<double>(GPS_TWO_PI);
             // Carrier discriminator filter
             carr_error_filt_hz = d_carrier_loop_filter.get_carrier_nco(carr_error_hz);
             // New carrier Doppler frequency estimation
@@ -376,7 +375,7 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
             d_acc_carrier_phase_rad -= GPS_TWO_PI * d_carrier_doppler_hz * Galileo_E1_CODE_PERIOD;
             //remnant carrier phase to prevent overflow in the code NCO
             d_rem_carr_phase_rad = d_rem_carr_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * Galileo_E1_CODE_PERIOD;
-            d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
+            d_rem_carr_phase_rad = std::fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
 
             // ################## DLL ##########################################################
             // DLL discriminator
@@ -400,7 +399,7 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
             T_prn_seconds = T_chip_seconds * Galileo_E1_B_CODE_LENGTH_CHIPS;
             T_prn_samples = T_prn_seconds * static_cast<double>(d_fs_in);
             K_blk_samples = T_prn_samples + d_rem_code_phase_samples + code_error_filt_secs * static_cast<double>(d_fs_in);
-            d_current_prn_length_samples = round(K_blk_samples); //round to a discrete samples
+            d_current_prn_length_samples = static_cast<int>(std::round(K_blk_samples)); //round to a discrete samples
             //d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; //rounding error < 1 sample
 
             // ####### CN0 ESTIMATION AND LOCK DETECTORS ######
@@ -457,7 +456,7 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
             // Tracking_timestamp_secs is aligned with the CURRENT PRN start sample (Hybridization OK!, but some glitches??)
             current_synchro_data.Tracking_timestamp_secs = (static_cast<double>(d_sample_counter) + static_cast<double>(d_rem_code_phase_samples)) / static_cast<double>(d_fs_in);
             //compute remnant code phase samples AFTER the Tracking timestamp
-            d_rem_code_phase_samples = K_blk_samples - d_current_prn_length_samples; //rounding error < 1 sample
+            d_rem_code_phase_samples = K_blk_samples - static_cast<double>(d_current_prn_length_samples); //rounding error < 1 sample
 
             // 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;
@@ -472,10 +471,9 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
              *  \todo The stop timer has to be moved to the signal source!
              */
             // stream to collect cout calls to improve thread safety
-            std::stringstream tmp_str_stream;
+            if (std::floor(d_sample_counter / d_fs_in) != d_last_seg)
-            if (floor(d_sample_counter / d_fs_in) != d_last_seg)
                 {
-                    d_last_seg = floor(d_sample_counter / d_fs_in);
+                    d_last_seg = std::floor(d_sample_counter / d_fs_in);
 
                     if (d_channel == 0)
                         {
@@ -498,9 +496,9 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items,gr_vect
     	 */
     	// stream to collect cout calls to improve thread safety
     	std::stringstream tmp_str_stream;
-    	if (floor(d_sample_counter / d_fs_in) != d_last_seg)
+    	if (std::floor(d_sample_counter / d_fs_in) != d_last_seg)
     	{
-    		d_last_seg = floor(d_sample_counter / d_fs_in);
+    		d_last_seg = std::floor(d_sample_counter / d_fs_in);
 
     		if (d_channel == 0)
     		{

src/algorithms/tracking/gnuradio_blocks/galileo_e1_dll_pll_veml_tracking_cc.h

@@ -126,8 +126,8 @@ private:
     long d_if_freq;
     long d_fs_in;
 
-    double d_early_late_spc_chips;
+    float d_early_late_spc_chips;
-    double d_very_early_late_spc_chips;
+    float d_very_early_late_spc_chips;
 
     gr_complex* d_ca_code;
 
@@ -146,22 +146,22 @@ private:
 
     // remaining code phase and carrier phase between tracking loops
     double d_rem_code_phase_samples;
-    double d_rem_carr_phase_rad;
+    float d_rem_carr_phase_rad;
 
     // PLL and DLL filter library
     Tracking_2nd_DLL_filter d_code_loop_filter;
     Tracking_2nd_PLL_filter d_carrier_loop_filter;
 
     // acquisition
-    double d_acq_code_phase_samples;
+    float d_acq_code_phase_samples;
-    double d_acq_carrier_doppler_hz;
+    float d_acq_carrier_doppler_hz;
 
     // correlator
     Correlator d_correlator;
 
     // tracking vars
     double d_code_freq_chips;
-    double d_carrier_doppler_hz;
+    float d_carrier_doppler_hz;
     double d_acc_carrier_phase_rad;
     double d_acc_code_phase_secs;
 
@@ -175,9 +175,9 @@ private:
     // CN0 estimation and lock detector
     int d_cn0_estimation_counter;
     gr_complex* d_Prompt_buffer;
-    double d_carrier_lock_test;
+    float d_carrier_lock_test;
-    double d_CN0_SNV_dB_Hz;
+    float d_CN0_SNV_dB_Hz;
-    double d_carrier_lock_threshold;
+    float d_carrier_lock_threshold;
     int d_carrier_lock_fail_counter;
 
     // control vars

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_tracking_cc.cc

@@ -297,7 +297,7 @@ void Gps_L1_Ca_Dll_Pll_Tracking_cc::update_local_code()
 void Gps_L1_Ca_Dll_Pll_Tracking_cc::update_local_carrier()
 {
     float sin_f, cos_f;
-    float phase_step_rad = static_cast<float>(GPS_TWO_PI) * static_cast<float>(d_carrier_doppler_hz) / static_cast<float>(d_fs_in);
+    float phase_step_rad = static_cast<float>(GPS_TWO_PI) * ( d_if_freq + d_carrier_doppler_hz ) / static_cast<float>(d_fs_in);
     int phase_step_rad_i = gr::fxpt::float_to_fixed(phase_step_rad);
     int phase_rad_i = gr::fxpt::float_to_fixed(d_rem_carr_phase_rad);
 
@@ -424,7 +424,7 @@ int Gps_L1_Ca_Dll_Pll_Tracking_cc::general_work (int noutput_items, gr_vector_in
             //carrier phase accumulator for (K) doppler estimation
             d_acc_carrier_phase_rad -= GPS_TWO_PI * d_carrier_doppler_hz * GPS_L1_CA_CODE_PERIOD;
             //remanent carrier phase to prevent overflow in the code NCO
-            d_rem_carr_phase_rad = d_rem_carr_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * GPS_L1_CA_CODE_PERIOD;
+            d_rem_carr_phase_rad = d_rem_carr_phase_rad + GPS_TWO_PI * ( d_if_freq + d_carrier_doppler_hz ) * GPS_L1_CA_CODE_PERIOD;
             d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
 
             // ################## DLL ##########################################################

src/algorithms/tracking/libs/CMakeLists.txt

@@ -40,6 +40,7 @@ set(TRACKING_LIB_SOURCES
      tracking_2nd_PLL_filter.cc
      tracking_discriminators.cc
      tracking_FLL_PLL_filter.cc
+     tracking_loop_filter.cc
 )
 
 include_directories(

src/algorithms/tracking/libs/correlator.cc

@@ -151,3 +151,50 @@ void Correlator::Carrier_wipeoff_and_EPL_volk_custom(int signal_length_samples,
     volk_cw_epl_corr_u(input, carrier, E_code, P_code, L_code, E_out, P_out, L_out, signal_length_samples);
 }
 #endif
+void Correlator::Carrier_rotate_and_EPL_volk(int signal_length_samples,
+                                             const gr_complex* input,
+                                             gr_complex *phase_as_complex,
+                                             gr_complex phase_inc_as_complex,
+                                             const gr_complex* E_code,
+                                             const gr_complex* P_code,
+                                             const gr_complex* L_code,
+                                             gr_complex* E_out,
+                                             gr_complex* P_out,
+                                             gr_complex* L_out )
+{
+    gr_complex* bb_signal = static_cast<gr_complex*>(volk_malloc(signal_length_samples * sizeof(gr_complex), volk_get_alignment()));
+
+    volk_32fc_s32fc_x2_rotator_32fc(bb_signal, input, phase_inc_as_complex, phase_as_complex, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(E_out, bb_signal, E_code, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(P_out, bb_signal, P_code, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(L_out, bb_signal, L_code, signal_length_samples);
+
+    volk_free(bb_signal);
+}
+
+void Correlator::Carrier_rotate_and_VEPL_volk(int signal_length_samples,
+                                              const gr_complex* input,
+                                              gr_complex *phase_as_complex,
+                                              gr_complex phase_inc_as_complex,
+                                              const gr_complex* VE_code,
+                                              const gr_complex* E_code,
+                                              const gr_complex* P_code,
+                                              const gr_complex* L_code,
+                                              const gr_complex* VL_code,
+                                              gr_complex* VE_out,
+                                              gr_complex* E_out,
+                                              gr_complex* P_out,
+                                              gr_complex* L_out,
+                                              gr_complex* VL_out )
+{
+    gr_complex* bb_signal = static_cast<gr_complex*>(volk_malloc(signal_length_samples * sizeof(gr_complex), volk_get_alignment()));
+
+    volk_32fc_s32fc_x2_rotator_32fc(bb_signal, input, phase_inc_as_complex, phase_as_complex, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(VE_out, bb_signal, VE_code, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(E_out, bb_signal, E_code, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(P_out, bb_signal, P_code, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(L_out, bb_signal, L_code, signal_length_samples);
+    volk_32fc_x2_dot_prod_32fc(VL_out, bb_signal, VL_code, signal_length_samples);
+
+    volk_free(bb_signal);
+}

src/algorithms/tracking/libs/correlator.h

@@ -56,13 +56,40 @@
 class Correlator
 {
 public:
+    Correlator();
+    ~Correlator();
     void Carrier_wipeoff_and_EPL_generic(int signal_length_samples, const gr_complex* input, gr_complex* carrier, gr_complex* E_code, gr_complex* P_code, gr_complex* L_code, gr_complex* E_out, gr_complex* P_out, gr_complex* L_out);
     void Carrier_wipeoff_and_EPL_volk(int signal_length_samples, const gr_complex* input, gr_complex* carrier, gr_complex* E_code, gr_complex* P_code, gr_complex* L_code, gr_complex* E_out, gr_complex* P_out, gr_complex* L_out);
     void Carrier_wipeoff_and_VEPL_volk(int signal_length_samples, const gr_complex* input, gr_complex* carrier, gr_complex* VE_code, gr_complex* E_code, gr_complex* P_code, gr_complex* L_code, gr_complex* VL_code, gr_complex* VE_out, gr_complex* E_out, gr_complex* P_out, gr_complex* L_out, gr_complex* VL_out);
     // void Carrier_wipeoff_and_EPL_volk_IQ(int prn_length_samples,int integration_time ,const gr_complex* input, gr_complex* carrier, gr_complex* E_code, gr_complex* P_code, gr_complex* L_code, gr_complex* P_data_code, gr_complex* E_out, gr_complex* P_out, gr_complex* L_out, gr_complex* P_data_out);
     void Carrier_wipeoff_and_EPL_volk_IQ(int signal_length_samples, const gr_complex* input, gr_complex* carrier, gr_complex* E_code, gr_complex* P_code, gr_complex* L_code, gr_complex* P_data_code, gr_complex* E_out, gr_complex* P_out, gr_complex* L_out, gr_complex* P_data_out);
-    Correlator();
+
-    ~Correlator();
+    void Carrier_rotate_and_EPL_volk(int signal_length_samples,
+            const gr_complex* input,
+            gr_complex *phase_as_complex,
+            gr_complex phase_inc_as_complex,
+            const gr_complex* E_code,
+            const gr_complex* P_code,
+            const gr_complex* L_code,
+            gr_complex* E_out,
+            gr_complex* P_out,
+            gr_complex* L_out );
+
+    void Carrier_rotate_and_VEPL_volk(int signal_length_samples,
+            const gr_complex* input,
+            gr_complex *phase_as_complex,
+            gr_complex phase_inc_as_complex,
+            const gr_complex* VE_code,
+            const gr_complex* E_code,
+            const gr_complex* P_code,
+            const gr_complex* L_code,
+            const gr_complex* VL_code,
+            gr_complex* VE_out,
+            gr_complex* E_out,
+            gr_complex* P_out,
+            gr_complex* L_out,
+            gr_complex* VL_out );
+
 #if USING_VOLK_CW_EPL_CORR_CUSTOM
     void Carrier_wipeoff_and_EPL_volk_custom(int signal_length_samples, const gr_complex* input, gr_complex* carrier, gr_complex* E_code, gr_complex* P_code, gr_complex* L_code, gr_complex* E_out, gr_complex* P_out, gr_complex* L_out);
 #endif

src/algorithms/tracking/libs/tracking_discriminators.cc

@@ -91,7 +91,7 @@ double pll_cloop_two_quadrant_atan(gr_complex prompt_s1)
 /*
  * DLL Noncoherent Early minus Late envelope normalized discriminator:
  * \f{equation}
- * 	error=\frac{E-L}{E+L},
+ * 	error=\frac{1}{2}\frac{E-L}{E+L},
  * \f}
  * where \f$E=\sqrt{I_{ES}^2+Q_{ES}^2}\f$ is the Early correlator output absolute value and
  * \f$L=\sqrt{I_{LS}^2+Q_{LS}^2}\f$ is the Late correlator output absolute value. The output is in [chips].
@@ -101,7 +101,14 @@ double dll_nc_e_minus_l_normalized(gr_complex early_s1, gr_complex late_s1)
     double P_early, P_late;
     P_early = std::abs(early_s1);
     P_late  = std::abs(late_s1);
-    return 0.5*(P_early - P_late) / ((P_early + P_late));
+    if( P_early + P_late == 0.0 )
+        {
+            return 0.0;
+        }
+    else
+        {
+            return 0.5 * (P_early - P_late) / ((P_early + P_late));
+        }
 }
 
 /*
@@ -118,5 +125,12 @@ double dll_nc_vemlp_normalized(gr_complex very_early_s1, gr_complex early_s1, gr
     double P_early, P_late;
     P_early = std::sqrt(std::norm(very_early_s1) + std::norm(early_s1));
     P_late  = std::sqrt(std::norm(very_late_s1) + std::norm(late_s1));
+    if( P_early + P_late == 0.0 )
+        {
+            return 0.0;
+        }
+    else
+        {
             return (P_early - P_late) / ((P_early + P_late));
+        }
 }

src/algorithms/tracking/libs/tracking_loop_filter.cc

@@ -0,0 +1,284 @@
+/*!
+ * \file tracking_loop_filter.cc
+ * \brief Generic 1st to 3rd order loop filter implementation
+ * \author Cillian O'Driscoll, 2015. cillian.odriscoll(at)gmail.com
+ *
+ * Class implementing a generic 1st, 2nd or 3rd order loop filter. Based
+ * on the bilinear transform of the standard Weiner filter.
+ *
+ * -------------------------------------------------------------------------
+ *
+ * Copyright (C) 2010-2015  (see AUTHORS file for a list of contributors)
+ *
+ * GNSS-SDR is a software defined Global Navigation
+ *          Satellite Systems receiver
+ *
+ * This file is part of GNSS-SDR.
+ *
+ * GNSS-SDR is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GNSS-SDR is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * -------------------------------------------------------------------------
+ */
+
+
+#include "tracking_loop_filter.h"
+#include <cmath>
+#include <glog/logging.h>
+
+
+#define MAX_LOOP_ORDER 3
+#define MAX_HISTORY_LENGTH 4
+
+Tracking_loop_filter::Tracking_loop_filter( float update_interval,
+                                            float noise_bandwidth,
+                                            int loop_order,
+                                            bool include_last_integrator )
+: d_loop_order( loop_order ),
+    d_current_index( 0 ),
+    d_include_last_integrator( include_last_integrator ),
+    d_noise_bandwidth( noise_bandwidth ),
+    d_update_interval( update_interval )
+{
+    d_inputs.resize( MAX_HISTORY_LENGTH, 0.0 );
+    d_outputs.resize( MAX_HISTORY_LENGTH, 0.0 );
+    update_coefficients();
+}
+
+Tracking_loop_filter::Tracking_loop_filter()
+: d_loop_order( 2 ),
+    d_current_index( 0 ),
+    d_include_last_integrator( false ),
+    d_noise_bandwidth( 15.0 ),
+    d_update_interval( 0.001 )
+{
+    d_inputs.resize( MAX_HISTORY_LENGTH, 0.0 );
+    d_outputs.resize( MAX_HISTORY_LENGTH, 0.0 );
+    update_coefficients();
+}
+
+Tracking_loop_filter::~Tracking_loop_filter()
+{
+    // Don't need to do anything here
+}
+
+float Tracking_loop_filter::apply( float current_input )
+{
+
+    // Now apply the filter coefficients:
+    float result  = 0;
+
+    // Hanlde the old outputs first:
+    for( unsigned int ii=0; ii < d_output_coefficients.size(); ++ii )
+    {
+        result += d_output_coefficients[ii] * d_outputs[ (d_current_index+ii)%MAX_HISTORY_LENGTH ];
+    }
+
+    // Now update the index to handle the inputs.
+    // DO NOT CHANGE THE ORDER OF THE ABOVE AND BELOW CODE
+    // SNIPPETS!!!!!!!
+
+    // Implementing a sort of circular buffer for the inputs and outputs
+    // the current input/output is at d_current_index, the nth previous
+    // input/output is at (d_current_index+n)%d_loop_order
+    d_current_index--;
+    if( d_current_index < 0 )
+    {
+        d_current_index += MAX_HISTORY_LENGTH;
+    }
+
+    d_inputs[d_current_index] = current_input;
+
+
+    for( unsigned int ii=0; ii < d_input_coefficients.size(); ++ii )
+    {
+        result += d_input_coefficients[ii] * d_inputs[ (d_current_index+ii)%MAX_HISTORY_LENGTH ];
+    }
+
+
+    d_outputs[d_current_index] = result;
+
+
+    return result;
+}
+
+void Tracking_loop_filter::update_coefficients( void )
+{
+    // Analog gains:
+    float g1;
+    float g2;
+    float g3;
+
+    // Natural frequency
+    float wn;
+    float T = d_update_interval;
+
+    float zeta = 1/std::sqrt(2);
+
+    // The following is based on the bilinear transform approximation of
+    // the analog integrator. The loop format is from Kaplan & Hegarty
+    // Table 5.6. The basic concept is that the loop has a cascade of
+    // integrators:
+    // 1 for a 1st order loop
+    // 2 for a 2nd order loop
+    // 3 for a 3rd order loop
+    // The bilinear transform approximates 1/s as
+    // T/2(1 + z^-1)/(1-z^-1) in the z domain.
+
+    switch( d_loop_order )
+    {
+        case 1:
+            wn = d_noise_bandwidth*4.0;
+            g1 = wn;
+            if( d_include_last_integrator )
+            {
+                d_input_coefficients.resize(2);
+                d_input_coefficients[0] = g1*T/2.0;
+                d_input_coefficients[1] = g1*T/2.0;
+
+                d_output_coefficients.resize(1);
+                d_output_coefficients[0] = 1;
+            }
+            else
+            {
+                d_input_coefficients.resize(1);
+                d_input_coefficients[0] = g1;
+
+                d_output_coefficients.resize(0);
+            }
+            break;
+        case 2:
+            wn = d_noise_bandwidth * (8*zeta)/ (4*zeta*zeta + 1 );
+            g1 = wn*wn;
+            g2 = wn*2*zeta;
+            if( d_include_last_integrator )
+            {
+                d_input_coefficients.resize(3);
+                d_input_coefficients[0] = T/2*( g1*T/2 + g2 );
+                d_input_coefficients[1] = T*T/2*g1;
+                d_input_coefficients[2] = T/2*( g1*T/2 - g2 );
+
+                d_output_coefficients.resize(2);
+                d_output_coefficients[0] = 2;
+                d_output_coefficients[1] = -1;
+            }
+            else
+            {
+                d_input_coefficients.resize(2);
+                d_input_coefficients[0] = ( g1*T/2.0+g2 );
+                d_input_coefficients[1] = g1*T/2-g2;
+
+                d_output_coefficients.resize(1);
+                d_output_coefficients[0] = 1;
+            }
+            break;
+
+        case 3:
+            wn = d_noise_bandwidth / 0.7845; // From Kaplan
+            float a3 = 1.1;
+            float b3 = 2.4;
+            g1 = wn*wn*wn;
+            g2 = a3*wn*wn;
+            g3 = b3*wn;
+
+            if( d_include_last_integrator )
+            {
+                d_input_coefficients.resize(4);
+                d_input_coefficients[0] = T/2*(  g3 + T/2*( g2 +   T/2*g1 ) );
+                d_input_coefficients[1] = T/2*( -g3 + T/2*( g2 + 3*T/2*g1 ) );
+                d_input_coefficients[2] = T/2*( -g3 - T/2*( g2 - 3*T/2*g1 ) );
+                d_input_coefficients[3] = T/2*(  g3 - T/2*( g2 -   T/2*g1 ) );
+
+                d_output_coefficients.resize(3);
+                d_output_coefficients[0] = 3;
+                d_output_coefficients[1] = -3;
+                d_output_coefficients[2] = 1;
+            }
+            else
+            {
+                d_input_coefficients.resize(3);
+                d_input_coefficients[0] = g3 + T/2*( g2 + T/2*g1 );
+                d_input_coefficients[1] = g1*T*T/2 -2*g3;
+                d_input_coefficients[2] = g3 + T/2*( -g2 + T/2*g1 );
+
+
+                d_output_coefficients.resize(2);
+                d_output_coefficients[0] = 2;
+                d_output_coefficients[1] = -1;
+            }
+            break;
+
+    };
+
+}
+
+void Tracking_loop_filter::set_noise_bandwidth( float noise_bandwidth )
+{
+    d_noise_bandwidth = noise_bandwidth;
+    update_coefficients();
+}
+
+float Tracking_loop_filter::get_noise_bandwidth( void ) const
+{
+    return d_noise_bandwidth;
+}
+
+void Tracking_loop_filter::set_update_interval( float update_interval )
+{
+    d_update_interval = update_interval;
+    update_coefficients();
+}
+
+float Tracking_loop_filter::get_update_interval( void ) const
+{
+    return d_update_interval;
+}
+
+void Tracking_loop_filter::set_include_last_integrator( bool include_last_integrator )
+{
+    d_include_last_integrator = include_last_integrator;
+    update_coefficients();
+}
+
+bool Tracking_loop_filter::get_include_last_integrator( void ) const
+{
+    return d_include_last_integrator;
+}
+
+void Tracking_loop_filter::set_order( int loop_order )
+{
+    if( loop_order < 1 || loop_order > MAX_LOOP_ORDER )
+    {
+        LOG(ERROR) << "Ignoring attempt to set loop order to " << loop_order
+            << ". Maximum allowed order is: " << MAX_LOOP_ORDER
+            << ". Not changing current value of " << d_loop_order;
+
+        return;
+
+    }
+
+    d_loop_order = loop_order;
+    update_coefficients();
+}
+
+int Tracking_loop_filter::get_order( void ) const
+{
+    return d_loop_order;
+}
+
+void Tracking_loop_filter::initialize( float initial_output )
+{
+    d_inputs.assign( MAX_HISTORY_LENGTH, 0.0 );
+    d_outputs.assign( MAX_HISTORY_LENGTH, initial_output );
+    d_current_index = MAX_HISTORY_LENGTH - 1;
+}

src/algorithms/tracking/libs/tracking_loop_filter.h

@@ -0,0 +1,98 @@
+/*!
+ * \file tracking_loop_filter.h
+ * \brief Generic 1st to 3rd order loop filter implementation
+ * \author Cillian O'Driscoll, 2015. cillian.odriscoll(at)gmail.com
+ *
+ * Class implementing a generic 1st, 2nd or 3rd order loop filter. Based
+ * on the bilinear transform of the standard Weiner filter.
+ *
+ * -------------------------------------------------------------------------
+ *
+ * Copyright (C) 2010-2015  (see AUTHORS file for a list of contributors)
+ *
+ * GNSS-SDR is a software defined Global Navigation
+ *          Satellite Systems receiver
+ *
+ * This file is part of GNSS-SDR.
+ *
+ * GNSS-SDR is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GNSS-SDR is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#ifndef GNSS_SDR_TRACKING_LOOP_FILTER_H_
+#define GNSS_SDR_TRACKING_LOOP_FILTER_H_
+
+#include <vector>
+
+
+/*!
+ * \brief This class implements a generic 1st, 2nd or 3rd order loop filter
+ *
+ */
+class Tracking_loop_filter
+{
+private:
+    // Store the last inputs and outputs:
+    std::vector< float > d_inputs;
+    std::vector< float > d_outputs;
+
+    // Store the filter coefficients:
+    std::vector< float > d_input_coefficients;
+    std::vector< float > d_output_coefficients;
+
+    // The loop order:
+    int d_loop_order;
+
+    // The current index in the i/o arrays:
+    int d_current_index;
+
+    // Should the last integrator be included?
+    bool d_include_last_integrator;
+
+    // The noise bandwidth (in Hz)
+    // Note this is an approximation only valid when the product of this
+    // number and the update interval (T) is small.
+    float d_noise_bandwidth;
+
+    // Loop update interval
+    float d_update_interval;
+
+    // Compute the filter coefficients:
+    void update_coefficients(void);
+
+
+public:
+    float get_noise_bandwidth(void) const;
+    float get_update_interval(void) const;
+    bool get_include_last_integrator(void) const;
+    int get_order(void) const;
+
+    void set_noise_bandwidth( float noise_bandwidth );
+    void set_update_interval( float update_interval );
+    void set_include_last_integrator( bool include_last_integrator );
+    void set_order( int loop_order );
+
+    void initialize(float initial_output = 0.0);
+    float apply(float current_input );
+
+    Tracking_loop_filter(float update_interval, float noise_bandwidth,
+            int loop_order = 2,
+            bool include_last_integrator = false );
+
+    Tracking_loop_filter();
+    ~Tracking_loop_filter();
+};
+
+#endif

src/core/receiver/gnss_flowgraph.cc

@@ -34,10 +34,13 @@
 
 #include "gnss_flowgraph.h"
 #include "unistd.h"
+
+#include <algorithm>
 #include <exception>
 #include <iostream>
 #include <set>
 #include <boost/lexical_cast.hpp>
+#include <boost/tokenizer.hpp>
 #include <glog/logging.h>
 #include "configuration_interface.h"
 #include "gnss_block_interface.h"
@@ -313,12 +316,12 @@ void GNSSFlowgraph::connect()
                 }
             channels_.at(i)->set_signal(available_GNSS_signals_.front());
             LOG(INFO) << "Channel " << i << " assigned to " << available_GNSS_signals_.front();
-            available_GNSS_signals_.pop_front();
             channels_.at(i)->start();
 
             if (channels_state_[i] == 1)
                 {
                     channels_.at(i)->start_acquisition();
+                    available_GNSS_signals_.pop_front();
                     LOG(INFO) << "Channel " << i << " connected to observables and ready for acquisition";
                 }
             else
@@ -413,13 +416,20 @@ void GNSSFlowgraph::apply_action(unsigned int who, unsigned int what)
         LOG(INFO) << "Channel " << who << " ACQ SUCCESS satellite " << channels_.at(who)->get_signal().get_satellite();
         channels_state_[who] = 2;
         acq_channels_count_--;
-        if (acq_channels_count_ < max_acq_channels_)
+        if (!available_GNSS_signals_.empty() && acq_channels_count_ < max_acq_channels_)
             {
                 for (unsigned int i = 0; i < channels_count_; i++)
                     {
                         if (channels_state_[i] == 0)
                             {
                                 channels_state_[i] = 1;
+                                while (channels_.at(i)->get_signal().get_signal_str().compare(available_GNSS_signals_.front().get_signal_str()) != 0 )
+                                    {
+                                        available_GNSS_signals_.push_back(available_GNSS_signals_.front());
+                                        available_GNSS_signals_.pop_front();
+                                    }
+                                channels_.at(i)->set_signal(available_GNSS_signals_.front());
+                                available_GNSS_signals_.pop_front();
                                 acq_channels_count_++;
                                 channels_.at(i)->start_acquisition();
                                 break;
@@ -442,6 +452,7 @@ void GNSSFlowgraph::apply_action(unsigned int who, unsigned int what)
             {
                 channels_state_[who] = 0;
                 channels_.at(who)->standby();
+                available_GNSS_signals_.push_back( channels_.at(who)->get_signal() );
             }
 
         // for (unsigned int i = 0; i < channels_count_; i++)
@@ -593,8 +604,55 @@ void GNSSFlowgraph::set_signals_list()
                     11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,
                     29, 30, 31, 32, 33, 34, 35, 36};
 
+    std::string sv_list = configuration_->property("Galileo.prns", std::string("") );
 
 
+    if( sv_list.length() > 0 )
+    {
+        // Reset the available prns:
+        std::set< unsigned int > tmp_set;
+        boost::tokenizer<> tok( sv_list );
+        std::transform( tok.begin(), tok.end(), std::inserter( tmp_set, tmp_set.begin() ),
+                boost::lexical_cast<unsigned int, std::string> );
+
+        if( tmp_set.size() > 0 )
+        {
+            available_galileo_prn = tmp_set;
+        }
+    }
+
+    sv_list = configuration_->property("GPS.prns", std::string("") );
+
+    if( sv_list.length() > 0 )
+    {
+        // Reset the available prns:
+        std::set< unsigned int > tmp_set;
+        boost::tokenizer<> tok( sv_list );
+        std::transform( tok.begin(), tok.end(), std::inserter( tmp_set, tmp_set.begin() ),
+                boost::lexical_cast<unsigned int, std::string> );
+
+        if( tmp_set.size() > 0 )
+        {
+            available_gps_prn = tmp_set;
+        }
+    }
+
+    sv_list = configuration_->property("SBAS.prns", std::string("") );
+
+    if( sv_list.length() > 0 )
+    {
+        // Reset the available prns:
+        std::set< unsigned int > tmp_set;
+        boost::tokenizer<> tok( sv_list );
+        std::transform( tok.begin(), tok.end(), std::inserter( tmp_set, tmp_set.begin() ),
+                boost::lexical_cast<unsigned int, std::string> );
+
+        if( tmp_set.size() > 0 )
+        {
+            available_sbas_prn = tmp_set;
+        }
+    }
+
     if ((configuration_->property("Channels_1C.count", 0) > 0) or (default_system.find(std::string("GPS")) != std::string::npos) or (default_signal.compare("1C") == 0) or (configuration_->property("Channels_GPS.count", 0) > 0) )
         {
             /*
@@ -691,8 +749,16 @@ void GNSSFlowgraph::set_signals_list()
                 }
             else
                 {
-                    Gnss_Signal signal_value = Gnss_Signal(Gnss_Satellite(gnss_system, gnss_it->get_satellite().get_PRN()), gnss_signal);
+                    Gnss_Signal signal_value = Gnss_Signal(Gnss_Satellite(gnss_system, ( sat != 0 ? sat : gnss_it->get_satellite().get_PRN())), gnss_signal);
+                    if( gnss_it == available_GNSS_signals_.begin() )
+                    {
                         available_GNSS_signals_.remove(signal_value);
+                        gnss_it = available_GNSS_signals_.begin();
+                    }
+                    else
+                    {
+                        available_GNSS_signals_.remove(signal_value);
+                    }
                     available_GNSS_signals_.insert(gnss_it, signal_value);
                 }
         }

src/core/system_parameters/gnss_signal.cc

@@ -73,7 +73,7 @@ bool operator==(const Gnss_Signal &sig1, const Gnss_Signal &sig2)
 
     if (sig1.get_satellite() == sig2.get_satellite())
         {
-            if (sig1.get_signal_str().compare(sig1.get_signal_str()))
+            if (sig1.get_signal_str().compare(sig1.get_signal_str()) == 0)
                 {
                     equal = true;
                 }

src/core/system_parameters/gnss_synchro.h

@@ -32,7 +32,7 @@
 #define GNSS_SDR_GNSS_SYNCHRO_H_
 
 #include "gnss_signal.h"
-#include <deque>
+
 
 /*!
  * \brief This is the class that contains the information that is shared

src/tests/CMakeLists.txt

@@ -337,6 +337,7 @@ endif(NOT ${GTEST_DIR_LOCAL})
 add_executable(trk_test
      ${CMAKE_CURRENT_SOURCE_DIR}/single_test_main.cc
      ${CMAKE_CURRENT_SOURCE_DIR}/gnss_block/galileo_e1_dll_pll_veml_tracking_test.cc
+     ${CMAKE_CURRENT_SOURCE_DIR}/arithmetic/tracking_loop_filter_test.cc
 )
 if(NOT ${ENABLE_PACKAGING})
      set_property(TARGET trk_test PROPERTY EXCLUDE_FROM_ALL TRUE)

src/tests/arithmetic/tracking_loop_filter_test.cc

@@ -0,0 +1,234 @@
+/*!
+ * \file tracking_loop_filter_test.cc
+ * \brief  This file implements tests for the general loop filter
+ * \author Cillian O'Driscoll, 2015. cillian.odriscoll(at)gmail.com
+ *
+ *
+ * -------------------------------------------------------------------------
+ *
+ * Copyright (C) 2010-2015  (see AUTHORS file for a list of contributors)
+ *
+ * GNSS-SDR is a software defined Global Navigation
+ *          Satellite Systems receiver
+ *
+ * This file is part of GNSS-SDR.
+ *
+ * GNSS-SDR is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GNSS-SDR is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * -------------------------------------------------------------------------
+ */
+
+#include "tracking_loop_filter.h"
+#include "tracking_2nd_PLL_filter.h"
+
+#include <gtest/gtest.h>
+
+TEST(TrackingLoopFilterTest, FirstOrderLoop)
+{
+    int loop_order = 1;
+    float noise_bandwidth = 5.0;
+    float update_interval = 0.001;
+    bool include_last_integrator = false;
+
+    Tracking_loop_filter theFilter( update_interval,
+            noise_bandwidth,
+            loop_order,
+            include_last_integrator );
+
+    EXPECT_EQ( theFilter.get_noise_bandwidth(), noise_bandwidth );
+    EXPECT_EQ( theFilter.get_update_interval(), update_interval );
+    EXPECT_EQ( theFilter.get_include_last_integrator(), include_last_integrator );
+    EXPECT_EQ( theFilter.get_order(), loop_order );
+
+    std::vector< float > sample_data = { 0, 0, 1.0, 0.0, 0.0, 0.0 };
+
+    theFilter.initialize( 0.0 );
+
+    float g1 = noise_bandwidth*4.0;
+
+    float result = 0.0;
+    for( unsigned int i = 0; i < sample_data.size(); ++i )
+    {
+        result = theFilter.apply( sample_data[i] );
+
+        ASSERT_FLOAT_EQ( result, sample_data[i]*g1 );
+    }
+}
+
+TEST(TrackingLoopFilterTest, FirstOrderLoopWithLastIntegrator)
+{
+    int loop_order = 1;
+    float noise_bandwidth = 5.0;
+    float update_interval = 0.001;
+    bool include_last_integrator = true;
+
+    Tracking_loop_filter theFilter( update_interval,
+            noise_bandwidth,
+            loop_order,
+            include_last_integrator );
+
+    EXPECT_EQ( theFilter.get_noise_bandwidth(), noise_bandwidth );
+    EXPECT_EQ( theFilter.get_update_interval(), update_interval );
+    EXPECT_EQ( theFilter.get_include_last_integrator(), include_last_integrator );
+    EXPECT_EQ( theFilter.get_order(), loop_order );
+
+    std::vector< float > sample_data = { 0, 0, 1.0, 0.0, 0.0, 0.0 };
+    std::vector< float > expected_out = { 0.0, 0.0, 0.01, 0.02, 0.02, 0.02 };
+
+    theFilter.initialize( 0.0 );
+
+    float g1 = noise_bandwidth*4.0;
+
+    float result = 0.0;
+    for( unsigned int i = 0; i < sample_data.size(); ++i )
+    {
+        result = theFilter.apply( sample_data[i] );
+        ASSERT_NEAR( result, expected_out[i], 1e-4 );
+    }
+    std::cout << std::endl;
+}
+
+
+
+TEST(TrackingLoopFilterTest, SecondOrderLoop)
+{
+    int loop_order = 2;
+    float noise_bandwidth = 5.0;
+    float update_interval = 0.001;
+    bool include_last_integrator = false;
+
+    Tracking_loop_filter theFilter( update_interval,
+            noise_bandwidth,
+            loop_order,
+            include_last_integrator );
+
+    EXPECT_EQ( theFilter.get_noise_bandwidth(), noise_bandwidth );
+    EXPECT_EQ( theFilter.get_update_interval(), update_interval );
+    EXPECT_EQ( theFilter.get_include_last_integrator(), include_last_integrator );
+    EXPECT_EQ( theFilter.get_order(), loop_order );
+
+    std::vector< float > sample_data = { 0, 0, 1.0, 0.0, 0.0, 0.0 };
+    std::vector< float > expected_out = { 0.0, 0.0, 13.37778, 0.0889, 0.0889, 0.0889 };
+
+    theFilter.initialize( 0.0 );
+
+    float result = 0.0;
+    for( unsigned int i = 0; i < sample_data.size(); ++i )
+    {
+        result = theFilter.apply( sample_data[i] );
+
+        ASSERT_NEAR( result, expected_out[i], 1e-4 );
+    }
+}
+
+TEST(TrackingLoopFilterTest, SecondOrderLoopWithLastIntegrator)
+{
+    int loop_order = 2;
+    float noise_bandwidth = 5.0;
+    float update_interval = 0.001;
+    bool include_last_integrator = true;
+
+    Tracking_loop_filter theFilter( update_interval,
+            noise_bandwidth,
+            loop_order,
+            include_last_integrator );
+
+    EXPECT_EQ( theFilter.get_noise_bandwidth(), noise_bandwidth );
+    EXPECT_EQ( theFilter.get_update_interval(), update_interval );
+    EXPECT_EQ( theFilter.get_include_last_integrator(), include_last_integrator );
+    EXPECT_EQ( theFilter.get_order(), loop_order );
+
+    std::vector< float > sample_data = { 0, 0, 1.0, 0.0, 0.0, 0.0 };
+    std::vector< float > expected_out = { 0.0, 0.0,  0.006689, 0.013422, 0.013511, 0.013600 };
+
+    theFilter.initialize( 0.0 );
+
+    float g1 = noise_bandwidth*4.0;
+
+    float result = 0.0;
+    for( unsigned int i = 0; i < sample_data.size(); ++i )
+    {
+        result = theFilter.apply( sample_data[i] );
+
+        ASSERT_NEAR( result, expected_out[i], 1e-4 );
+    }
+    std::cout << std::endl;
+}
+
+
+TEST(TrackingLoopFilterTest, ThirdOrderLoop)
+{
+    int loop_order = 3;
+    float noise_bandwidth = 5.0;
+    float update_interval = 0.001;
+    bool include_last_integrator = false;
+
+    Tracking_loop_filter theFilter( update_interval,
+            noise_bandwidth,
+            loop_order,
+            include_last_integrator );
+
+    EXPECT_EQ( theFilter.get_noise_bandwidth(), noise_bandwidth );
+    EXPECT_EQ( theFilter.get_update_interval(), update_interval );
+    EXPECT_EQ( theFilter.get_include_last_integrator(), include_last_integrator );
+    EXPECT_EQ( theFilter.get_order(), loop_order );
+
+    std::vector< float > sample_data = { 0, 0, 1.0, 0.0, 0.0, 0.0 };
+    std::vector< float > expected_out = { 0.0, 0.0, 15.31877, 0.04494, 0.04520, 0.04546};
+
+    theFilter.initialize( 0.0 );
+
+    float result = 0.0;
+    for( unsigned int i = 0; i < sample_data.size(); ++i )
+    {
+        result = theFilter.apply( sample_data[i] );
+
+        ASSERT_NEAR( result, expected_out[i], 1e-4 );
+    }
+}
+
+TEST(TrackingLoopFilterTest, ThirdOrderLoopWithLastIntegrator)
+{
+    int loop_order = 3;
+    float noise_bandwidth = 5.0;
+    float update_interval = 0.001;
+    bool include_last_integrator = true;
+
+    Tracking_loop_filter theFilter( update_interval,
+            noise_bandwidth,
+            loop_order,
+            include_last_integrator );
+
+    EXPECT_EQ( theFilter.get_noise_bandwidth(), noise_bandwidth );
+    EXPECT_EQ( theFilter.get_update_interval(), update_interval );
+    EXPECT_EQ( theFilter.get_include_last_integrator(), include_last_integrator );
+    EXPECT_EQ( theFilter.get_order(), loop_order );
+
+    std::vector< float > sample_data = { 0, 0, 1.0, 0.0, 0.0, 0.0 };
+    std::vector< float > expected_out = { 0.0, 0.0, 0.007659, 0.015341, 0.015386, 0.015432};
+
+    theFilter.initialize( 0.0 );
+
+    float g1 = noise_bandwidth*4.0;
+
+    float result = 0.0;
+    for( unsigned int i = 0; i < sample_data.size(); ++i )
+    {
+        result = theFilter.apply( sample_data[i] );
+        ASSERT_NEAR( result, expected_out[i], 1e-4 );
+    }
+    std::cout << std::endl;
+}
+
+

src/utils/matlab/libs/gps_l1_ca_dll_pll_read_tracking_dump.m

@@ -35,7 +35,7 @@ function [GNSS_tracking] = gps_l1_ca_dll_pll_read_tracking_dump (filename, count
 
   m = nargchk (1,2,nargin);
   num_float_vars=16;
-  num_double_vars=1;
+  num_double_vars=2;
   double_size_bytes=8;
   float_size_bytes=4;
   skip_bytes_each_read=float_size_bytes*num_float_vars+double_size_bytes*num_double_vars;
@@ -100,6 +100,9 @@ function [GNSS_tracking] = gps_l1_ca_dll_pll_read_tracking_dump (filename, count
             bytes_shift=bytes_shift+float_size_bytes;
     fseek(f,bytes_shift,'bof'); % move to next interleaved float
     v17 = fread (f, count, 'float64',skip_bytes_each_read-double_size_bytes);
+            bytes_shift=bytes_shift+double_size_bytes;
+    fseek(f,bytes_shift,'bof'); % move to next interleaved float
+    v18 = fread (f, count, 'float64',skip_bytes_each_read-double_size_bytes);
     fclose (f);
     
     %%%%%%%% output vars %%%%%%%%
@@ -155,6 +158,7 @@ function [GNSS_tracking] = gps_l1_ca_dll_pll_read_tracking_dump (filename, count
     carrier_lock_test=v15;
     var1=v16;
     var2=v17;
+    var3=v18;
     
     GNSS_tracking.E=E;
     GNSS_tracking.P=P;
@@ -173,5 +177,6 @@ function [GNSS_tracking] = gps_l1_ca_dll_pll_read_tracking_dump (filename, count
     GNSS_tracking.carrier_lock_test=carrier_lock_test;
     GNSS_tracking.var1=var1;
     GNSS_tracking.var2=var2;
+    GNSS_tracking.var3=var3;
   end