Merge branch 'next' of https://github.com/carlesfernandez/gnss-sdr into next

.clang-format

@@ -51,7 +51,7 @@ IncludeBlocks: Merge
 IncludeCategories:
   - Regex:           '^.*.h"'
     Priority:        1
-  - Regex:           '^.*(boost|gflags|glog|gtest|gnuradio|volk|gnsssdr)/'
+  - Regex:           '^.*(boost|gflags|glog|gtest|gnsssdr|gnuradio|pmt|uhd|volk)/'
     Priority:        2
   - Regex:           '^.*(armadillo|matio)'
     Priority:        2

src/algorithms/acquisition/adapters/galileo_e1_pcps_8ms_ambiguous_acquisition.h

@@ -131,6 +131,9 @@ public:
 
     void set_state(int state __attribute__((unused))) override{};
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
+
 private:
     ConfigurationInterface* configuration_;
     galileo_pcps_8ms_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc

@@ -50,7 +50,6 @@ GalileoE1PcpsAmbiguousAcquisition::GalileoE1PcpsAmbiguousAcquisition(
                                 in_streams_(in_streams),
                                 out_streams_(out_streams)
 {
-    Acq_Conf acq_parameters;
     configuration_ = configuration;
     std::string default_item_type = "gr_complex";
     std::string default_dump_filename = "./acquisition.mat";
@@ -61,41 +60,67 @@ GalileoE1PcpsAmbiguousAcquisition::GalileoE1PcpsAmbiguousAcquisition(
 
     int64_t fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 4000000);
     fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
-    acq_parameters.fs_in = fs_in_;
+    acq_parameters_.fs_in = fs_in_;
-    acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E1_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
     doppler_max_ = configuration_->property(role + ".doppler_max", 5000);
     if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
-    acq_parameters.doppler_max = doppler_max_;
+    acq_parameters_.doppler_max = doppler_max_;
-    acq_parameters.ms_per_code = 4;
+    acq_parameters_.ms_per_code = 4;
-    sampled_ms_ = configuration_->property(role + ".coherent_integration_time_ms", acq_parameters.ms_per_code);
+    sampled_ms_ = configuration_->property(role + ".coherent_integration_time_ms", acq_parameters_.ms_per_code);
-    acq_parameters.sampled_ms = sampled_ms_;
+    acq_parameters_.sampled_ms = sampled_ms_;
-    if ((acq_parameters.sampled_ms % acq_parameters.ms_per_code) != 0)
+    if ((acq_parameters_.sampled_ms % acq_parameters_.ms_per_code) != 0)
         {
             LOG(WARNING) << "Parameter coherent_integration_time_ms should be a multiple of 4. Setting it to 4";
-            acq_parameters.sampled_ms = acq_parameters.ms_per_code;
+            acq_parameters_.sampled_ms = acq_parameters_.ms_per_code;
         }
     bit_transition_flag_ = configuration_->property(role + ".bit_transition_flag", false);
-    acq_parameters.bit_transition_flag = bit_transition_flag_;
+    acq_parameters_.bit_transition_flag = bit_transition_flag_;
     use_CFAR_algorithm_flag_ = configuration_->property(role + ".use_CFAR_algorithm", true);  //will be false in future versions
-    acq_parameters.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
+    acq_parameters_.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
     acquire_pilot_ = configuration_->property(role + ".acquire_pilot", false);  //will be true in future versions
     max_dwells_ = configuration_->property(role + ".max_dwells", 1);
-    acq_parameters.max_dwells = max_dwells_;
+    acq_parameters_.max_dwells = max_dwells_;
     dump_ = configuration_->property(role + ".dump", false);
-    acq_parameters.dump = dump_;
+    acq_parameters_.dump = dump_;
-    acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);
+    acq_parameters_.dump_channel = configuration_->property(role + ".dump_channel", 0);
     blocking_ = configuration_->property(role + ".blocking", true);
-    acq_parameters.blocking = blocking_;
+    acq_parameters_.blocking = blocking_;
     dump_filename_ = configuration_->property(role + ".dump_filename", default_dump_filename);
-    acq_parameters.dump_filename = dump_filename_;
+    acq_parameters_.dump_filename = dump_filename_;
-    //--- Find number of samples per spreading code (4 ms)  -----------------
-    code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (Galileo_E1_CODE_CHIP_RATE_HZ / Galileo_E1_B_CODE_LENGTH_CHIPS)));
 
-    float samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+    acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    acq_parameters.samples_per_ms = samples_per_ms;
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
-    acq_parameters.samples_per_code = acq_parameters.samples_per_ms * static_cast<float>(Galileo_E1_CODE_PERIOD_MS);
+        {
-    vector_length_ = sampled_ms_ * samples_per_ms;
+            LOG(WARNING) << "Galileo E1 acqisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
+            acq_parameters_.use_automatic_resampler = false;
+        }
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            if (acq_parameters_.fs_in > Galileo_E1_OPT_ACQ_FS_HZ)
+                {
+                    acq_parameters_.resampler_ratio = floor(static_cast<float>(acq_parameters_.fs_in) / Galileo_E1_OPT_ACQ_FS_HZ);
+                    uint32_t decimation = acq_parameters_.fs_in / Galileo_E1_OPT_ACQ_FS_HZ;
+                    while (acq_parameters_.fs_in % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    acq_parameters_.resampler_ratio = decimation;
+                    acq_parameters_.resampled_fs = acq_parameters_.fs_in / static_cast<int>(acq_parameters_.resampler_ratio);
+                }
+            //--- Find number of samples per spreading code (4 ms)  -----------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(acq_parameters_.resampled_fs) / (Galileo_E1_CODE_CHIP_RATE_HZ / Galileo_E1_B_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(acq_parameters_.resampled_fs) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E1_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters_.resampled_fs)));
+        }
+    else
+        {
+            //--- Find number of samples per spreading code (4 ms)  -----------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (Galileo_E1_CODE_CHIP_RATE_HZ / Galileo_E1_B_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E1_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters_.fs_in)));
+        }
 
+    acq_parameters_.samples_per_code = acq_parameters_.samples_per_ms * static_cast<float>(Galileo_E1_CODE_PERIOD_MS);
+    vector_length_ = sampled_ms_ * acq_parameters_.samples_per_ms;
     if (bit_transition_flag_)
         {
             vector_length_ *= 2;
@@ -111,12 +136,12 @@ GalileoE1PcpsAmbiguousAcquisition::GalileoE1PcpsAmbiguousAcquisition(
         {
             item_size_ = sizeof(gr_complex);
         }
-    acq_parameters.it_size = item_size_;
+    acq_parameters_.it_size = item_size_;
-    acq_parameters.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
+    acq_parameters_.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
-    acq_parameters.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
+    acq_parameters_.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
-    acq_parameters.make_2_steps = configuration_->property(role + ".make_two_steps", false);
+    acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
-    acq_parameters.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
+    acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
-    acquisition_ = pcps_make_acquisition(acq_parameters);
+    acquisition_ = pcps_make_acquisition(acq_parameters_);
     DLOG(INFO) << "acquisition(" << acquisition_->unique_id() << ")";
 
     if (item_type_ == "cbyte")
@@ -227,13 +252,29 @@ void GalileoE1PcpsAmbiguousAcquisition::set_local_code()
         {
             //set local signal generator to Galileo E1 pilot component (1C)
             char pilot_signal[3] = "1C";
-            galileo_e1_code_gen_complex_sampled(code, pilot_signal,
+            if (acq_parameters_.use_automatic_resampler)
-                cboc, gnss_synchro_->PRN, fs_in_, 0, false);
+                {
+                    galileo_e1_code_gen_complex_sampled(code, pilot_signal,
+                        cboc, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0, false);
+                }
+            else
+                {
+                    galileo_e1_code_gen_complex_sampled(code, pilot_signal,
+                        cboc, gnss_synchro_->PRN, fs_in_, 0, false);
+                }
         }
     else
         {
-            galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+            if (acq_parameters_.use_automatic_resampler)
-                cboc, gnss_synchro_->PRN, fs_in_, 0, false);
+                {
+                    galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+                        cboc, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0, false);
+                }
+            else
+                {
+                    galileo_e1_code_gen_complex_sampled(code, gnss_synchro_->Signal,
+                        cboc, gnss_synchro_->PRN, fs_in_, 0, false);
+                }
         }
 
 
@@ -352,3 +393,8 @@ gr::basic_block_sptr GalileoE1PcpsAmbiguousAcquisition::get_right_block()
 {
     return acquisition_;
 }
+
+void GalileoE1PcpsAmbiguousAcquisition::set_resampler_latency(uint32_t latency_samples)
+{
+    acquisition_->set_resampler_latency(latency_samples);
+}

src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.h

@@ -32,6 +32,7 @@
 #ifndef GNSS_SDR_GALILEO_E1_PCPS_AMBIGUOUS_ACQUISITION_H_
 #define GNSS_SDR_GALILEO_E1_PCPS_AMBIGUOUS_ACQUISITION_H_
 
+#include "acq_conf.h"
 #include "acquisition_interface.h"
 #include "complex_byte_to_float_x2.h"
 #include "gnss_synchro.h"
@@ -137,8 +138,16 @@ public:
      */
     void stop_acquisition() override;
 
+    /*!
+     * \brief Sets the resampler latency to account it in the acquisition code delay estimation
+     */
+
+    void set_resampler_latency(uint32_t latency_samples) override;
+
+
 private:
     ConfigurationInterface* configuration_;
+    Acq_Conf acq_parameters_;
     pcps_acquisition_sptr acquisition_;
     gr::blocks::float_to_complex::sptr float_to_complex_;
     complex_byte_to_float_x2_sptr cbyte_to_float_x2_;

src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition_fpga.h

@@ -142,6 +142,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     //pcps_acquisition_sptr acquisition_;

src/algorithms/acquisition/adapters/galileo_e1_pcps_cccwsr_ambiguous_acquisition.h

@@ -131,6 +131,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_cccwsr_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/galileo_e1_pcps_quicksync_ambiguous_acquisition.h

@@ -135,6 +135,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_quicksync_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/galileo_e1_pcps_tong_ambiguous_acquisition.h

@@ -134,6 +134,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_tong_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/galileo_e5a_noncoherent_iq_acquisition_caf.h

@@ -137,6 +137,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     galileo_e5a_noncoherentIQ_acquisition_caf_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc

@@ -49,7 +49,6 @@ GalileoE5aPcpsAcquisition::GalileoE5aPcpsAcquisition(ConfigurationInterface* con
                                 in_streams_(in_streams),
                                 out_streams_(out_streams)
 {
-    Acq_Conf acq_parameters = Acq_Conf();
     configuration_ = configuration;
     std::string default_item_type = "gr_complex";
     std::string default_dump_filename = "./acquisition.mat";
@@ -60,8 +59,7 @@ GalileoE5aPcpsAcquisition::GalileoE5aPcpsAcquisition(ConfigurationInterface* con
 
     int64_t fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 32000000);
     fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
-    acq_parameters.fs_in = fs_in_;
+    acq_parameters_.fs_in = fs_in_;
-    acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E5a_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
     acq_pilot_ = configuration_->property(role + ".acquire_pilot", false);
     acq_iq_ = configuration_->property(role + ".acquire_iq", false);
     if (acq_iq_)
@@ -69,22 +67,58 @@ GalileoE5aPcpsAcquisition::GalileoE5aPcpsAcquisition(ConfigurationInterface* con
             acq_pilot_ = false;
         }
     dump_ = configuration_->property(role + ".dump", false);
-    acq_parameters.dump = dump_;
+    acq_parameters_.dump = dump_;
-    acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);
+    acq_parameters_.dump_channel = configuration_->property(role + ".dump_channel", 0);
     doppler_max_ = configuration_->property(role + ".doppler_max", 5000);
     if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
-    acq_parameters.doppler_max = doppler_max_;
+    acq_parameters_.doppler_max = doppler_max_;
     sampled_ms_ = 1;
     max_dwells_ = configuration_->property(role + ".max_dwells", 1);
-    acq_parameters.max_dwells = max_dwells_;
+    acq_parameters_.max_dwells = max_dwells_;
     dump_filename_ = configuration_->property(role + ".dump_filename", default_dump_filename);
-    acq_parameters.dump_filename = dump_filename_;
+    acq_parameters_.dump_filename = dump_filename_;
     bit_transition_flag_ = configuration_->property(role + ".bit_transition_flag", false);
-    acq_parameters.bit_transition_flag = bit_transition_flag_;
+    acq_parameters_.bit_transition_flag = bit_transition_flag_;
     use_CFAR_ = configuration_->property(role + ".use_CFAR_algorithm", false);
-    acq_parameters.use_CFAR_algorithm_flag = use_CFAR_;
+    acq_parameters_.use_CFAR_algorithm_flag = use_CFAR_;
     blocking_ = configuration_->property(role + ".blocking", true);
-    acq_parameters.blocking = blocking_;
+    acq_parameters_.blocking = blocking_;
+
+
+    acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
+        {
+            LOG(WARNING) << "Galileo E5a acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
+            acq_parameters_.use_automatic_resampler = false;
+        }
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            if (acq_parameters_.fs_in > Galileo_E5a_OPT_ACQ_FS_HZ)
+                {
+                    acq_parameters_.resampler_ratio = floor(static_cast<float>(acq_parameters_.fs_in) / Galileo_E5a_OPT_ACQ_FS_HZ);
+                    uint32_t decimation = acq_parameters_.fs_in / Galileo_E5a_OPT_ACQ_FS_HZ;
+                    while (acq_parameters_.fs_in % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    acq_parameters_.resampler_ratio = decimation;
+                    acq_parameters_.resampled_fs = acq_parameters_.fs_in / static_cast<int>(acq_parameters_.resampler_ratio);
+                }
+
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(acq_parameters_.resampled_fs) / (Galileo_E5a_CODE_CHIP_RATE_HZ / Galileo_E5a_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(acq_parameters_.resampled_fs) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E5a_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters_.resampled_fs)));
+        }
+    else
+        {
+            acq_parameters_.resampled_fs = fs_in_;
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (Galileo_E5a_CODE_CHIP_RATE_HZ / Galileo_E5a_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E5a_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters_.fs_in)));
+        }
+
     //--- Find number of samples per spreading code (1ms)-------------------------
     code_length_ = static_cast<unsigned int>(std::round(static_cast<double>(fs_in_) / Galileo_E5a_CODE_CHIP_RATE_HZ * static_cast<double>(Galileo_E5a_CODE_LENGTH_CHIPS)));
     vector_length_ = code_length_ * sampled_ms_;
@@ -104,16 +138,15 @@ GalileoE5aPcpsAcquisition::GalileoE5aPcpsAcquisition(ConfigurationInterface* con
             item_size_ = sizeof(gr_complex);
             LOG(WARNING) << item_type_ << " unknown acquisition item type";
         }
-    acq_parameters.it_size = item_size_;
+    acq_parameters_.it_size = item_size_;
-    acq_parameters.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+    acq_parameters_.sampled_ms = sampled_ms_;
-    acq_parameters.sampled_ms = sampled_ms_;
+    acq_parameters_.ms_per_code = 1;
-    acq_parameters.ms_per_code = 1;
+    acq_parameters_.samples_per_code = acq_parameters_.samples_per_ms * static_cast<float>(GALILEO_E5a_CODE_PERIOD_MS);
-    acq_parameters.samples_per_code = acq_parameters.samples_per_ms * static_cast<float>(GALILEO_E5a_CODE_PERIOD_MS);
+    acq_parameters_.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
-    acq_parameters.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
+    acq_parameters_.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
-    acq_parameters.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
+    acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
-    acq_parameters.make_2_steps = configuration_->property(role + ".make_two_steps", false);
+    acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
-    acq_parameters.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
+    acquisition_ = pcps_make_acquisition(acq_parameters_);
-    acquisition_ = pcps_make_acquisition(acq_parameters);
 
     channel_ = 0;
     threshold_ = 0.0;
@@ -224,7 +257,14 @@ void GalileoE5aPcpsAcquisition::set_local_code()
             strcpy(signal_, "5I");
         }
 
-    galileo_e5_a_code_gen_complex_sampled(code, signal_, gnss_synchro_->PRN, fs_in_, 0);
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            galileo_e5_a_code_gen_complex_sampled(code, signal_, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0);
+        }
+    else
+        {
+            galileo_e5_a_code_gen_complex_sampled(code, signal_, gnss_synchro_->PRN, fs_in_, 0);
+        }
 
     for (unsigned int i = 0; i < sampled_ms_; i++)
         {
@@ -311,3 +351,8 @@ gr::basic_block_sptr GalileoE5aPcpsAcquisition::get_right_block()
 {
     return acquisition_;
 }
+
+void GalileoE5aPcpsAcquisition::set_resampler_latency(uint32_t latency_samples)
+{
+    acquisition_->set_resampler_latency(latency_samples);
+}

src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.h

@@ -128,13 +128,19 @@ public:
      */
     void stop_acquisition() override;
 
+    /*!
+     * \brief Sets the resampler latency to account it in the acquisition code delay estimation
+     */
+
+    void set_resampler_latency(uint32_t latency_samples) override;
+
 private:
     float calculate_threshold(float pfa);
 
     ConfigurationInterface* configuration_;
 
     pcps_acquisition_sptr acquisition_;
-
+    Acq_Conf acq_parameters_;
     size_t item_size_;
 
     std::string item_type_;

src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition_fpga.h

@@ -130,6 +130,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     //float calculate_threshold(float pfa);
 

src/algorithms/acquisition/adapters/glonass_l1_ca_pcps_acquisition.h

@@ -137,6 +137,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_acquisition_sptr acquisition_;

src/algorithms/acquisition/adapters/glonass_l2_ca_pcps_acquisition.h

@@ -136,6 +136,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_acquisition_sptr acquisition_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc

@@ -54,7 +54,6 @@ GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
                                 in_streams_(in_streams),
                                 out_streams_(out_streams)
 {
-    Acq_Conf acq_parameters = Acq_Conf();
     configuration_ = configuration;
     std::string default_item_type = "gr_complex";
     std::string default_dump_filename = "./acquisition.mat";
@@ -64,36 +63,64 @@ GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
     item_type_ = configuration_->property(role + ".item_type", default_item_type);
     int64_t fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
     fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
-    acq_parameters.fs_in = fs_in_;
+    acq_parameters_.fs_in = fs_in_;
-    acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters.fs_in)));
     dump_ = configuration_->property(role + ".dump", false);
-    acq_parameters.dump = dump_;
+    acq_parameters_.dump = dump_;
-    acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);
+    acq_parameters_.dump_channel = configuration_->property(role + ".dump_channel", 0);
     blocking_ = configuration_->property(role + ".blocking", true);
-    acq_parameters.blocking = blocking_;
+    acq_parameters_.blocking = blocking_;
     doppler_max_ = configuration_->property(role + ".doppler_max", 5000);
     if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
-    acq_parameters.doppler_max = doppler_max_;
+    acq_parameters_.doppler_max = doppler_max_;
     sampled_ms_ = configuration_->property(role + ".coherent_integration_time_ms", 1);
-    acq_parameters.sampled_ms = sampled_ms_;
+    acq_parameters_.sampled_ms = sampled_ms_;
-    acq_parameters.ms_per_code = 1;
+    acq_parameters_.ms_per_code = 1;
     bit_transition_flag_ = configuration_->property(role + ".bit_transition_flag", false);
-    acq_parameters.bit_transition_flag = bit_transition_flag_;
+    acq_parameters_.bit_transition_flag = bit_transition_flag_;
     use_CFAR_algorithm_flag_ = configuration_->property(role + ".use_CFAR_algorithm", true);  //will be false in future versions
-    acq_parameters.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
+    acq_parameters_.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
     max_dwells_ = configuration_->property(role + ".max_dwells", 1);
-    acq_parameters.max_dwells = max_dwells_;
+    acq_parameters_.max_dwells = max_dwells_;
     dump_filename_ = configuration_->property(role + ".dump_filename", default_dump_filename);
-    acq_parameters.dump_filename = dump_filename_;
+    acq_parameters_.dump_filename = dump_filename_;
-    acq_parameters.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
+    acq_parameters_.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
-    acq_parameters.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
+    acq_parameters_.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
-    acq_parameters.make_2_steps = configuration_->property(role + ".make_two_steps", false);
+    acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
-    //--- Find number of samples per spreading code -------------------------
+    acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
-    code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (GPS_L1_CA_CODE_RATE_HZ / GPS_L1_CA_CODE_LENGTH_CHIPS)));
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
-    acq_parameters.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+        {
-    acq_parameters.samples_per_code = acq_parameters.samples_per_ms * static_cast<float>(GPS_L1_CA_CODE_PERIOD * 1000.0);
+            LOG(WARNING) << "GPS L1 CA acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
+            acq_parameters_.use_automatic_resampler = false;
+        }
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            if (acq_parameters_.fs_in > GPS_L1_CA_OPT_ACQ_FS_HZ)
+                {
+                    acq_parameters_.resampler_ratio = floor(static_cast<float>(acq_parameters_.fs_in) / GPS_L1_CA_OPT_ACQ_FS_HZ);
+                    uint32_t decimation = acq_parameters_.fs_in / GPS_L1_CA_OPT_ACQ_FS_HZ;
+                    while (acq_parameters_.fs_in % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    acq_parameters_.resampler_ratio = decimation;
+                    acq_parameters_.resampled_fs = acq_parameters_.fs_in / static_cast<int>(acq_parameters_.resampler_ratio);
+                }
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(acq_parameters_.resampled_fs) / (GPS_L1_CA_CODE_RATE_HZ / GPS_L1_CA_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(acq_parameters_.resampled_fs) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters_.resampled_fs)));
+        }
+    else
+        {
+            acq_parameters_.resampled_fs = fs_in_;
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (GPS_L1_CA_CODE_RATE_HZ / GPS_L1_CA_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters_.fs_in)));
+        }
 
-    vector_length_ = std::floor(acq_parameters.sampled_ms * acq_parameters.samples_per_ms) * (acq_parameters.bit_transition_flag ? 2 : 1);
+    acq_parameters_.samples_per_code = acq_parameters_.samples_per_ms * static_cast<float>(GPS_L1_CA_CODE_PERIOD * 1000.0);
+    vector_length_ = std::floor(acq_parameters_.sampled_ms * acq_parameters_.samples_per_ms) * (acq_parameters_.bit_transition_flag ? 2 : 1);
     code_ = new gr_complex[vector_length_];
 
     if (item_type_ == "cshort")
@@ -105,9 +132,9 @@ GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
             item_size_ = sizeof(gr_complex);
         }
 
-    acq_parameters.it_size = item_size_;
+    acq_parameters_.it_size = item_size_;
-    acq_parameters.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
+    acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
-    acquisition_ = pcps_make_acquisition(acq_parameters);
+    acquisition_ = pcps_make_acquisition(acq_parameters_);
     DLOG(INFO) << "acquisition(" << acquisition_->unique_id() << ")";
 
     if (item_type_ == "cbyte")
@@ -208,8 +235,14 @@ void GpsL1CaPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+    if (acq_parameters_.use_automatic_resampler)
-
+        {
+            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, acq_parameters_.resampled_fs, 0);
+        }
+    else
+        {
+            gps_l1_ca_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_, 0);
+        }
     for (unsigned int i = 0; i < sampled_ms_; i++)
         {
             memcpy(&(code_[i * code_length_]), code,
@@ -325,3 +358,8 @@ gr::basic_block_sptr GpsL1CaPcpsAcquisition::get_right_block()
 {
     return acquisition_;
 }
+
+void GpsL1CaPcpsAcquisition::set_resampler_latency(uint32_t latency_samples)
+{
+    acquisition_->set_resampler_latency(latency_samples);
+}

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.h

@@ -36,6 +36,7 @@
 #ifndef GNSS_SDR_GPS_L1_CA_PCPS_ACQUISITION_H_
 #define GNSS_SDR_GPS_L1_CA_PCPS_ACQUISITION_H_
 
+#include "acq_conf.h"
 #include "acquisition_interface.h"
 #include "complex_byte_to_float_x2.h"
 #include "gnss_synchro.h"
@@ -141,9 +142,17 @@ public:
      */
     void stop_acquisition() override;
 
+    /*!
+     * \brief Sets the resampler latency to account it in the acquisition code delay estimation
+     */
+
+    void set_resampler_latency(uint32_t latency_samples) override;
+
+
 private:
     ConfigurationInterface* configuration_;
     pcps_acquisition_sptr acquisition_;
+    Acq_Conf acq_parameters_;
     gr::blocks::float_to_complex::sptr float_to_complex_;
     complex_byte_to_float_x2_sptr cbyte_to_float_x2_;
     size_t item_size_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition_fine_doppler.h

@@ -132,6 +132,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     pcps_acquisition_fine_doppler_cc_sptr acquisition_cc_;
     size_t item_size_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition_fpga.h

@@ -140,6 +140,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_acquisition_fpga_sptr acquisition_fpga_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_assisted_acquisition.h

@@ -128,6 +128,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     pcps_assisted_acquisition_cc_sptr acquisition_cc_;
     size_t item_size_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_opencl_acquisition.h

@@ -130,6 +130,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_opencl_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_quicksync_acquisition.h

@@ -136,6 +136,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_quicksync_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/gps_l1_ca_pcps_tong_acquisition.h

@@ -135,6 +135,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     pcps_tong_acquisition_cc_sptr acquisition_cc_;

src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc

@@ -52,7 +52,6 @@ GpsL2MPcpsAcquisition::GpsL2MPcpsAcquisition(
                                 in_streams_(in_streams),
                                 out_streams_(out_streams)
 {
-    Acq_Conf acq_parameters = Acq_Conf();
     configuration_ = configuration;
     std::string default_item_type = "gr_complex";
     std::string default_dump_filename = "./acquisition.mat";
@@ -60,42 +59,73 @@ GpsL2MPcpsAcquisition::GpsL2MPcpsAcquisition(
     LOG(INFO) << "role " << role;
 
     item_type_ = configuration_->property(role + ".item_type", default_item_type);
-    //float pfa =  configuration_->property(role + ".pfa", 0.0);
-
     int64_t fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
     fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
-    acq_parameters.fs_in = fs_in_;
+    acq_parameters_.fs_in = fs_in_;
-    acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L2_M_CODE_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
     dump_ = configuration_->property(role + ".dump", false);
-    acq_parameters.dump = dump_;
+    acq_parameters_.dump = dump_;
-    acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);
+    acq_parameters_.dump_channel = configuration_->property(role + ".dump_channel", 0);
     blocking_ = configuration_->property(role + ".blocking", true);
-    acq_parameters.blocking = blocking_;
+    acq_parameters_.blocking = blocking_;
     doppler_max_ = configuration->property(role + ".doppler_max", 5000);
     if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
-    acq_parameters.doppler_max = doppler_max_;
+    acq_parameters_.doppler_max = doppler_max_;
     bit_transition_flag_ = configuration_->property(role + ".bit_transition_flag", false);
-    acq_parameters.bit_transition_flag = bit_transition_flag_;
+    acq_parameters_.bit_transition_flag = bit_transition_flag_;
     use_CFAR_algorithm_flag_ = configuration_->property(role + ".use_CFAR_algorithm", true);  //will be false in future versions
-    acq_parameters.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
+    acq_parameters_.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
     max_dwells_ = configuration_->property(role + ".max_dwells", 1);
-    acq_parameters.max_dwells = max_dwells_;
+    acq_parameters_.max_dwells = max_dwells_;
     dump_filename_ = configuration_->property(role + ".dump_filename", default_dump_filename);
-    acq_parameters.dump_filename = dump_filename_;
+    acq_parameters_.dump_filename = dump_filename_;
-    //--- Find number of samples per spreading code -------------------------
+    acq_parameters_.ms_per_code = 20;
-    acq_parameters.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+    acq_parameters_.sampled_ms = configuration_->property(role + ".coherent_integration_time_ms", acq_parameters_.ms_per_code);
-    acq_parameters.ms_per_code = 20;
+    if ((acq_parameters_.sampled_ms % acq_parameters_.ms_per_code) != 0)
-    acq_parameters.sampled_ms = configuration_->property(role + ".coherent_integration_time_ms", acq_parameters.ms_per_code);
-    if ((acq_parameters.sampled_ms % acq_parameters.ms_per_code) != 0)
         {
             LOG(WARNING) << "Parameter coherent_integration_time_ms should be a multiple of 20. Setting it to 20";
-            acq_parameters.sampled_ms = acq_parameters.ms_per_code;
+            acq_parameters_.sampled_ms = acq_parameters_.ms_per_code;
         }
 
-    code_length_ = acq_parameters.ms_per_code * acq_parameters.samples_per_ms;
+    acq_parameters_.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
+    acq_parameters_.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
+    acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
+    acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
+    acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
+        {
+            LOG(WARNING) << "GPS L2CM acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
+            acq_parameters_.use_automatic_resampler = false;
+        }
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            if (acq_parameters_.fs_in > GPS_L2C_OPT_ACQ_FS_HZ)
+                {
+                    acq_parameters_.resampler_ratio = floor(static_cast<float>(acq_parameters_.fs_in) / GPS_L2C_OPT_ACQ_FS_HZ);
+                    uint32_t decimation = acq_parameters_.fs_in / GPS_L2C_OPT_ACQ_FS_HZ;
+                    while (acq_parameters_.fs_in % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    acq_parameters_.resampler_ratio = decimation;
+                    acq_parameters_.resampled_fs = acq_parameters_.fs_in / static_cast<int>(acq_parameters_.resampler_ratio);
+                }
 
-    vector_length_ = acq_parameters.sampled_ms * acq_parameters.samples_per_ms * (acq_parameters.bit_transition_flag ? 2 : 1);
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(acq_parameters_.resampled_fs) / (GPS_L2_M_CODE_RATE_HZ / GPS_L2_M_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(acq_parameters_.resampled_fs) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L2_M_CODE_RATE_HZ) * static_cast<float>(acq_parameters_.resampled_fs)));
+        }
+    else
+        {
+            acq_parameters_.resampled_fs = fs_in_;
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (GPS_L2_M_CODE_RATE_HZ / GPS_L2_M_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L2_M_CODE_RATE_HZ) * static_cast<float>(acq_parameters_.fs_in)));
+        }
 
+    acq_parameters_.samples_per_code = acq_parameters_.samples_per_ms * static_cast<float>(GPS_L2_M_PERIOD * 1000.0);
+    vector_length_ = acq_parameters_.sampled_ms * acq_parameters_.samples_per_ms * (acq_parameters_.bit_transition_flag ? 2 : 1);
     code_ = new gr_complex[vector_length_];
 
     if (item_type_ == "cshort")
@@ -107,14 +137,8 @@ GpsL2MPcpsAcquisition::GpsL2MPcpsAcquisition(
             item_size_ = sizeof(gr_complex);
         }
 
-    acq_parameters.samples_per_code = acq_parameters.samples_per_ms * static_cast<float>(GPS_L2_M_PERIOD * 1000.0);
+    acq_parameters_.it_size = item_size_;
-    acq_parameters.it_size = item_size_;
+    acquisition_ = pcps_make_acquisition(acq_parameters_);
-
-    acq_parameters.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
-    acq_parameters.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
-    acq_parameters.make_2_steps = configuration_->property(role + ".make_two_steps", false);
-    acq_parameters.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
-    acquisition_ = pcps_make_acquisition(acq_parameters);
     DLOG(INFO) << "acquisition(" << acquisition_->unique_id() << ")";
 
     if (item_type_ == "cbyte")
@@ -127,7 +151,7 @@ GpsL2MPcpsAcquisition::GpsL2MPcpsAcquisition(
     threshold_ = 0.0;
     doppler_step_ = 0;
     gnss_synchro_ = nullptr;
-    num_codes_ = acq_parameters.sampled_ms / acq_parameters.ms_per_code;
+    num_codes_ = acq_parameters_.sampled_ms / acq_parameters_.ms_per_code;
     if (in_streams_ > 1)
         {
             LOG(ERROR) << "This implementation only supports one input stream";
@@ -223,7 +247,16 @@ void GpsL2MPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    gps_l2c_m_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_);
+
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            gps_l2c_m_code_gen_complex_sampled(code, gnss_synchro_->PRN, acq_parameters_.resampled_fs);
+        }
+    else
+        {
+            gps_l2c_m_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_);
+        }
+
 
     for (unsigned int i = 0; i < num_codes_; i++)
         {
@@ -339,3 +372,7 @@ gr::basic_block_sptr GpsL2MPcpsAcquisition::get_right_block()
 {
     return acquisition_;
 }
+void GpsL2MPcpsAcquisition::set_resampler_latency(uint32_t latency_samples)
+{
+    acquisition_->set_resampler_latency(latency_samples);
+}

src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.h

@@ -139,9 +139,17 @@ public:
      */
     void stop_acquisition() override;
 
+    /*!
+     * \brief Sets the resampler latency to account it in the acquisition code delay estimation
+     */
+
+    void set_resampler_latency(uint32_t latency_samples) override;
+
+
 private:
     ConfigurationInterface* configuration_;
     pcps_acquisition_sptr acquisition_;
+    Acq_Conf acq_parameters_;
     gr::blocks::float_to_complex::sptr float_to_complex_;
     complex_byte_to_float_x2_sptr cbyte_to_float_x2_;
     size_t item_size_;

src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition_fpga.h

@@ -140,6 +140,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     //pcps_acquisition_sptr acquisition_;

src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc

@@ -52,7 +52,6 @@ GpsL5iPcpsAcquisition::GpsL5iPcpsAcquisition(
                                 in_streams_(in_streams),
                                 out_streams_(out_streams)
 {
-    Acq_Conf acq_parameters = Acq_Conf();
     configuration_ = configuration;
     std::string default_item_type = "gr_complex";
     std::string default_dump_filename = "./acquisition.mat";
@@ -63,32 +62,24 @@ GpsL5iPcpsAcquisition::GpsL5iPcpsAcquisition(
 
     int64_t fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
     fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
-    acq_parameters.fs_in = fs_in_;
+    acq_parameters_.fs_in = fs_in_;
-    acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L5i_CODE_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
     dump_ = configuration_->property(role + ".dump", false);
-    acq_parameters.dump = dump_;
+    acq_parameters_.dump = dump_;
-    acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);
+    acq_parameters_.dump_channel = configuration_->property(role + ".dump_channel", 0);
     blocking_ = configuration_->property(role + ".blocking", true);
-    acq_parameters.blocking = blocking_;
+    acq_parameters_.blocking = blocking_;
     doppler_max_ = configuration->property(role + ".doppler_max", 5000);
     if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
-    acq_parameters.doppler_max = doppler_max_;
+    acq_parameters_.doppler_max = doppler_max_;
     bit_transition_flag_ = configuration_->property(role + ".bit_transition_flag", false);
-    acq_parameters.bit_transition_flag = bit_transition_flag_;
+    acq_parameters_.bit_transition_flag = bit_transition_flag_;
     use_CFAR_algorithm_flag_ = configuration_->property(role + ".use_CFAR_algorithm", true);  //will be false in future versions
-    acq_parameters.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
+    acq_parameters_.use_CFAR_algorithm_flag = use_CFAR_algorithm_flag_;
     max_dwells_ = configuration_->property(role + ".max_dwells", 1);
-    acq_parameters.max_dwells = max_dwells_;
+    acq_parameters_.max_dwells = max_dwells_;
     dump_filename_ = configuration_->property(role + ".dump_filename", default_dump_filename);
-    acq_parameters.dump_filename = dump_filename_;
+    acq_parameters_.dump_filename = dump_filename_;
-    acq_parameters.sampled_ms = configuration_->property(role + ".coherent_integration_time_ms", 1);
+    acq_parameters_.sampled_ms = configuration_->property(role + ".coherent_integration_time_ms", 1);
-    //--- Find number of samples per spreading code -------------------------
-    code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (GPS_L5i_CODE_RATE_HZ / GPS_L5i_CODE_LENGTH_CHIPS)));
-    acq_parameters.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
-    acq_parameters.samples_per_code = acq_parameters.samples_per_ms * static_cast<float>(GPS_L5i_PERIOD * 1000.0);
-
-    vector_length_ = std::floor(acq_parameters.sampled_ms * acq_parameters.samples_per_ms) * (acq_parameters.bit_transition_flag ? 2 : 1);
-    code_ = new gr_complex[vector_length_];
 
     if (item_type_ == "cshort")
         {
@@ -99,14 +90,51 @@ GpsL5iPcpsAcquisition::GpsL5iPcpsAcquisition(
             item_size_ = sizeof(gr_complex);
         }
 
-    acq_parameters.ms_per_code = 1;
+    acq_parameters_.ms_per_code = 1;
-    acq_parameters.it_size = item_size_;
+    acq_parameters_.it_size = item_size_;
-    num_codes_ = acq_parameters.sampled_ms;
+    num_codes_ = acq_parameters_.sampled_ms;
-    acq_parameters.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
+    acq_parameters_.num_doppler_bins_step2 = configuration_->property(role + ".second_nbins", 4);
-    acq_parameters.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
+    acq_parameters_.doppler_step2 = configuration_->property(role + ".second_doppler_step", 125.0);
-    acq_parameters.make_2_steps = configuration_->property(role + ".make_two_steps", false);
+    acq_parameters_.make_2_steps = configuration_->property(role + ".make_two_steps", false);
-    acq_parameters.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
+    acq_parameters_.blocking_on_standby = configuration_->property(role + ".blocking_on_standby", false);
-    acquisition_ = pcps_make_acquisition(acq_parameters);
+    acq_parameters_.use_automatic_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
+    if (acq_parameters_.use_automatic_resampler == true and item_type_ != "gr_complex")
+        {
+            LOG(WARNING) << "GPS L5 acquisition disabled the automatic resampler feature because its item_type is not set to gr_complex";
+            acq_parameters_.use_automatic_resampler = false;
+        }
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            if (acq_parameters_.fs_in > GPS_L5_OPT_ACQ_FS_HZ)
+                {
+                    acq_parameters_.resampler_ratio = floor(static_cast<float>(acq_parameters_.fs_in) / GPS_L5_OPT_ACQ_FS_HZ);
+                    uint32_t decimation = acq_parameters_.fs_in / GPS_L5_OPT_ACQ_FS_HZ;
+                    while (acq_parameters_.fs_in % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    acq_parameters_.resampler_ratio = decimation;
+                    acq_parameters_.resampled_fs = acq_parameters_.fs_in / static_cast<int>(acq_parameters_.resampler_ratio);
+                }
+
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(acq_parameters_.resampled_fs) / (GPS_L5i_CODE_RATE_HZ / GPS_L5i_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(acq_parameters_.resampled_fs) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L5i_CODE_RATE_HZ) * static_cast<float>(acq_parameters_.resampled_fs)));
+        }
+    else
+        {
+            acq_parameters_.resampled_fs = fs_in_;
+            //--- Find number of samples per spreading code -------------------------
+            code_length_ = static_cast<unsigned int>(std::floor(static_cast<double>(fs_in_) / (GPS_L5i_CODE_RATE_HZ / GPS_L5i_CODE_LENGTH_CHIPS)));
+            acq_parameters_.samples_per_ms = static_cast<float>(fs_in_) * 0.001;
+            acq_parameters_.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L5i_CODE_RATE_HZ) * static_cast<float>(acq_parameters_.fs_in)));
+        }
+
+    acq_parameters_.samples_per_code = acq_parameters_.samples_per_ms * static_cast<float>(GPS_L5i_PERIOD * 1000.0);
+    vector_length_ = std::floor(acq_parameters_.sampled_ms * acq_parameters_.samples_per_ms) * (acq_parameters_.bit_transition_flag ? 2 : 1);
+    code_ = new gr_complex[vector_length_];
+    acquisition_ = pcps_make_acquisition(acq_parameters_);
     DLOG(INFO) << "acquisition(" << acquisition_->unique_id() << ")";
 
     if (item_type_ == "cbyte")
@@ -114,6 +142,7 @@ GpsL5iPcpsAcquisition::GpsL5iPcpsAcquisition(
             cbyte_to_float_x2_ = make_complex_byte_to_float_x2();
             float_to_complex_ = gr::blocks::float_to_complex::make();
         }
+
     channel_ = 0;
     threshold_ = 0.0;
     doppler_step_ = 0;
@@ -211,7 +240,15 @@ void GpsL5iPcpsAcquisition::set_local_code()
 {
     auto* code = new std::complex<float>[code_length_];
 
-    gps_l5i_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_);
+
+    if (acq_parameters_.use_automatic_resampler)
+        {
+            gps_l5i_code_gen_complex_sampled(code, gnss_synchro_->PRN, acq_parameters_.resampled_fs);
+        }
+    else
+        {
+            gps_l5i_code_gen_complex_sampled(code, gnss_synchro_->PRN, fs_in_);
+        }
 
     for (unsigned int i = 0; i < num_codes_; i++)
         {
@@ -327,3 +364,8 @@ gr::basic_block_sptr GpsL5iPcpsAcquisition::get_right_block()
 {
     return acquisition_;
 }
+
+void GpsL5iPcpsAcquisition::set_resampler_latency(uint32_t latency_samples)
+{
+    acquisition_->set_resampler_latency(latency_samples);
+}

src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.h

@@ -139,9 +139,16 @@ public:
      */
     void stop_acquisition() override;
 
+    /*!
+     * \brief Sets the resampler latency to account it in the acquisition code delay estimation
+     */
+
+    void set_resampler_latency(uint32_t latency_samples) override;
+
 private:
     ConfigurationInterface* configuration_;
     pcps_acquisition_sptr acquisition_;
+    Acq_Conf acq_parameters_;
     gr::blocks::float_to_complex::sptr float_to_complex_;
     complex_byte_to_float_x2_sptr cbyte_to_float_x2_;
     size_t item_size_;

src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition_fpga.h

@@ -140,6 +140,8 @@ public:
      */
     void stop_acquisition() override;
 
+    void set_resampler_latency(uint32_t latency_samples __attribute__((unused))) override{};
+
 private:
     ConfigurationInterface* configuration_;
     //pcps_acquisition_sptr acquisition_;

src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc

@@ -221,6 +221,12 @@ pcps_acquisition::~pcps_acquisition()
 }
 
 
+void pcps_acquisition::set_resampler_latency(uint32_t latency_samples)
+{
+    gr::thread::scoped_lock lock(d_setlock);  // require mutex with work function called by the scheduler
+    acq_parameters.resampler_latency_samples = latency_samples;
+}
+
 void pcps_acquisition::set_local_code(std::complex<float>* code)
 {
     // reset the intermediate frequency
@@ -280,7 +286,15 @@ bool pcps_acquisition::is_fdma()
 
 void pcps_acquisition::update_local_carrier(gr_complex* carrier_vector, int32_t correlator_length_samples, float freq)
 {
-    float phase_step_rad = GPS_TWO_PI * freq / static_cast<float>(acq_parameters.fs_in);
+    float phase_step_rad;
+    if (acq_parameters.use_automatic_resampler)
+        {
+            phase_step_rad = GPS_TWO_PI * freq / static_cast<float>(acq_parameters.resampled_fs);
+        }
+    else
+        {
+            phase_step_rad = GPS_TWO_PI * freq / static_cast<float>(acq_parameters.fs_in);
+        }
     float _phase[1];
     _phase[0] = 0.0;
     volk_gnsssdr_s32f_sincos_32fc(carrier_vector, -phase_step_rad, _phase, correlator_length_samples);
@@ -716,9 +730,20 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
                 {
                     d_test_statistics = first_vs_second_peak_statistic(indext, doppler, d_num_doppler_bins, acq_parameters.doppler_max, d_doppler_step);
                 }
-            d_gnss_synchro->Acq_delay_samples = static_cast<double>(std::fmod(static_cast<float>(indext), acq_parameters.samples_per_code));
+            if (acq_parameters.use_automatic_resampler)
-            d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
+                {
-            d_gnss_synchro->Acq_samplestamp_samples = samp_count;
+                    //take into account the acquisition resampler ratio
+                    d_gnss_synchro->Acq_delay_samples = static_cast<double>(std::fmod(static_cast<float>(indext), acq_parameters.samples_per_code)) * acq_parameters.resampler_ratio;
+                    d_gnss_synchro->Acq_delay_samples -= static_cast<double>(acq_parameters.resampler_latency_samples);  //account the resampler filter latency
+                    d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
+                    d_gnss_synchro->Acq_samplestamp_samples = rint(static_cast<double>(samp_count) * acq_parameters.resampler_ratio);
+                }
+            else
+                {
+                    d_gnss_synchro->Acq_delay_samples = static_cast<double>(std::fmod(static_cast<float>(indext), acq_parameters.samples_per_code));
+                    d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
+                    d_gnss_synchro->Acq_samplestamp_samples = samp_count;
+                }
         }
     else
         {
@@ -762,10 +787,23 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
                 {
                     d_test_statistics = first_vs_second_peak_statistic(indext, doppler, d_num_doppler_bins_step2, static_cast<int32_t>(d_doppler_center_step_two - (static_cast<float>(d_num_doppler_bins_step2) / 2.0) * acq_parameters.doppler_step2), acq_parameters.doppler_step2);
                 }
-            d_gnss_synchro->Acq_delay_samples = static_cast<double>(std::fmod(static_cast<float>(indext), acq_parameters.samples_per_code));
+
-            d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
+            if (acq_parameters.use_automatic_resampler)
-            d_gnss_synchro->Acq_samplestamp_samples = samp_count;
+                {
-            d_gnss_synchro->Acq_doppler_step = acq_parameters.doppler_step2;
+                    //take into account the acquisition resampler ratio
+                    d_gnss_synchro->Acq_delay_samples = static_cast<double>(std::fmod(static_cast<float>(indext), acq_parameters.samples_per_code)) * acq_parameters.resampler_ratio;
+                    d_gnss_synchro->Acq_delay_samples -= static_cast<double>(acq_parameters.resampler_latency_samples);  //account the resampler filter latency
+                    d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
+                    d_gnss_synchro->Acq_samplestamp_samples = rint(static_cast<double>(samp_count) * acq_parameters.resampler_ratio);
+                    d_gnss_synchro->Acq_doppler_step = acq_parameters.doppler_step2;
+                }
+            else
+                {
+                    d_gnss_synchro->Acq_delay_samples = static_cast<double>(std::fmod(static_cast<float>(indext), acq_parameters.samples_per_code));
+                    d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
+                    d_gnss_synchro->Acq_samplestamp_samples = samp_count;
+                    d_gnss_synchro->Acq_doppler_step = acq_parameters.doppler_step2;
+                }
         }
 
     lk.lock();
@@ -865,6 +903,12 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
         }
 }
 
+// Called by gnuradio to enable drivers, etc for i/o devices.
+bool pcps_acquisition::start()
+{
+    d_sample_counter = 0ULL;
+    return true;
+}
 
 int pcps_acquisition::general_work(int noutput_items __attribute__((unused)),
     gr_vector_int& ninput_items, gr_vector_const_void_star& input_items,

src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.h

@@ -98,6 +98,9 @@ private:
     float first_vs_second_peak_statistic(uint32_t& indext, int32_t& doppler, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step);
     float max_to_input_power_statistic(uint32_t& indext, int32_t& doppler, float input_power, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step);
 
+    bool start();
+
+
     Acq_Conf acq_parameters;
     bool d_active;
     bool d_worker_active;
@@ -233,6 +236,9 @@ public:
         d_doppler_step = doppler_step;
     }
 
+
+    void set_resampler_latency(uint32_t latency_samples);
+
     /*!
       * \brief Parallel Code Phase Search Acquisition signal processing.
       */

src/algorithms/acquisition/libs/acq_conf.cc

@@ -53,4 +53,8 @@ Acq_Conf::Acq_Conf()
     dump_channel = 0U;
     it_size = sizeof(char);
     blocking_on_standby = false;
+    use_automatic_resampler = false;
+    resampler_ratio = 1.0;
+    resampled_fs = 0LL;
+    resampler_latency_samples = 0U;
 }

src/algorithms/acquisition/libs/acq_conf.h

@@ -56,6 +56,10 @@ public:
     bool blocking;
     bool blocking_on_standby;  // enable it only for unit testing to avoid sample consume on idle status
     bool make_2_steps;
+    bool use_automatic_resampler;
+    float resampler_ratio;
+    int64_t resampled_fs;
+    uint32_t resampler_latency_samples;
     std::string dump_filename;
     uint32_t dump_channel;
     size_t it_size;

src/algorithms/channel/adapters/channel.cc

@@ -38,12 +38,10 @@
 using google::LogMessage;
 
 // Constructor
-Channel::Channel(ConfigurationInterface* configuration, uint32_t channel,
+Channel::Channel(ConfigurationInterface* configuration, uint32_t channel, std::shared_ptr<AcquisitionInterface> acq,
-    std::shared_ptr<GNSSBlockInterface> pass_through, std::shared_ptr<AcquisitionInterface> acq,
     std::shared_ptr<TrackingInterface> trk, std::shared_ptr<TelemetryDecoderInterface> nav,
     std::string role, std::string implementation, gr::msg_queue::sptr queue)
 {
-    pass_through_ = std::move(pass_through);
     acq_ = std::move(acq);
     trk_ = std::move(trk);
     nav_ = std::move(nav);
@@ -112,32 +110,15 @@ Channel::~Channel() = default;
 
 void Channel::connect(gr::top_block_sptr top_block)
 {
-    if (connected_)
-        {
-            LOG(WARNING) << "channel already connected internally";
-            return;
-        }
-    if (flag_enable_fpga == false)
-        {
-            pass_through_->connect(top_block);
-        }
     acq_->connect(top_block);
     trk_->connect(top_block);
     nav_->connect(top_block);
 
     //Synchronous ports
-    if (flag_enable_fpga == false)
-        {
-            top_block->connect(pass_through_->get_right_block(), 0, acq_->get_left_block(), 0);
-            DLOG(INFO) << "pass_through_ -> acquisition";
-            top_block->connect(pass_through_->get_right_block(), 0, trk_->get_left_block(), 0);
-            DLOG(INFO) << "pass_through_ -> tracking";
-        }
     top_block->connect(trk_->get_right_block(), 0, nav_->get_left_block(), 0);
     DLOG(INFO) << "tracking -> telemetry_decoder";
 
     // Message ports
-
     top_block->msg_connect(acq_->get_right_block(), pmt::mp("events"), channel_msg_rx, pmt::mp("events"));
     top_block->msg_connect(trk_->get_right_block(), pmt::mp("events"), channel_msg_rx, pmt::mp("events"));
 
@@ -153,17 +134,8 @@ void Channel::disconnect(gr::top_block_sptr top_block)
             return;
         }
 
-    if (flag_enable_fpga == false)
-        {
-            top_block->disconnect(pass_through_->get_right_block(), 0, acq_->get_left_block(), 0);
-            top_block->disconnect(pass_through_->get_right_block(), 0, trk_->get_left_block(), 0);
-        }
     top_block->disconnect(trk_->get_right_block(), 0, nav_->get_left_block(), 0);
 
-    if (flag_enable_fpga == false)
-        {
-            pass_through_->disconnect(top_block);
-        }
     acq_->disconnect(top_block);
     trk_->disconnect(top_block);
     nav_->disconnect(top_block);
@@ -173,9 +145,19 @@ void Channel::disconnect(gr::top_block_sptr top_block)
 
 gr::basic_block_sptr Channel::get_left_block()
 {
-    return pass_through_->get_left_block();
+    LOG(ERROR) << "Deprecated call to get_left_block() in channel interface";
+    return nullptr;
 }
 
+gr::basic_block_sptr Channel::get_left_block_trk()
+{
+    return trk_->get_left_block();
+}
+
+gr::basic_block_sptr Channel::get_left_block_acq()
+{
+    return acq_->get_left_block();
+}
 
 gr::basic_block_sptr Channel::get_right_block()
 {

src/algorithms/channel/adapters/channel.h

@@ -60,16 +60,17 @@ class Channel : public ChannelInterface
 {
 public:
     //! Constructor
-    Channel(ConfigurationInterface* configuration, uint32_t channel,
+    Channel(ConfigurationInterface* configuration, uint32_t channel, std::shared_ptr<AcquisitionInterface> acq,
-        std::shared_ptr<GNSSBlockInterface> pass_through, std::shared_ptr<AcquisitionInterface> acq,
         std::shared_ptr<TrackingInterface> trk, std::shared_ptr<TelemetryDecoderInterface> nav,
         std::string role, std::string implementation, gr::msg_queue::sptr queue);
     //! Virtual destructor
     virtual ~Channel();
 
-    void connect(gr::top_block_sptr top_block) override;
+    void connect(gr::top_block_sptr top_block) override;  //!< connects the tracking block to the top_block and to the telemetry
     void disconnect(gr::top_block_sptr top_block) override;
-    gr::basic_block_sptr get_left_block() override;
+    gr::basic_block_sptr get_left_block() override;      //!< gets the gnuradio tracking block pointer
+    gr::basic_block_sptr get_left_block_trk() override;  //!< gets the gnuradio tracking block pointer
+    gr::basic_block_sptr get_left_block_acq() override;  //!< gets the gnuradio tracking block pointer
     gr::basic_block_sptr get_right_block() override;
 
     inline std::string role() override { return role_; }
@@ -88,7 +89,6 @@ public:
 
 private:
     channel_msg_receiver_cc_sptr channel_msg_rx;
-    std::shared_ptr<GNSSBlockInterface> pass_through_;
     std::shared_ptr<AcquisitionInterface> acq_;
     std::shared_ptr<TrackingInterface> trk_;
     std::shared_ptr<TelemetryDecoderInterface> nav_;

src/algorithms/resampler/adapters/mmse_resampler_conditioner.cc

@@ -69,7 +69,7 @@ MmseResamplerConditioner::MmseResamplerConditioner(
             std::vector<float> taps = gr::filter::firdes::low_pass(1.0,
                 sample_freq_in_,
                 sample_freq_out_ / 2.1,
-                sample_freq_out_ / 10,
+                sample_freq_out_ / 5,
                 gr::filter::firdes::win_type::WIN_HAMMING);
             std::cout << "Enabled fractional resampler low pass filter with " << taps.size() << " taps" << std::endl;
             fir_filter_ccf_ = gr::filter::fir_filter_ccf::make(1, taps);

src/algorithms/signal_source/adapters/uhd_signal_source.cc

@@ -33,10 +33,10 @@
 #include "configuration_interface.h"
 #include "gnss_sdr_valve.h"
 #include <glog/logging.h>
-#include <volk/volk.h>
-#include <iostream>
 #include <uhd/exception.hpp>
 #include <uhd/types/device_addr.hpp>
+#include <volk/volk.h>
+#include <iostream>
 #include <utility>
 
 

src/algorithms/tracking/gnuradio_blocks/glonass_l1_ca_dll_pll_c_aid_tracking_cc.cc

@@ -47,11 +47,11 @@
 #include <glog/logging.h>
 #include <gnuradio/io_signature.h>
 #include <matio.h>
+#include <pmt/pmt.h>
 #include <volk_gnsssdr/volk_gnsssdr.h>
 #include <cmath>
 #include <iostream>
 #include <memory>
-#include <pmt/pmt.h>
 #include <sstream>
 #include <utility>
 

src/algorithms/tracking/gnuradio_blocks/glonass_l1_ca_dll_pll_c_aid_tracking_cc.h

@@ -45,10 +45,10 @@
 //#include "tracking_loop_filter.h"
 #include "cpu_multicorrelator.h"
 #include <gnuradio/block.h>
+#include <pmt/pmt.h>
 #include <deque>
 #include <fstream>
 #include <map>
-#include <pmt/pmt.h>
 #include <string>
 
 class glonass_l1_ca_dll_pll_c_aid_tracking_cc;

src/algorithms/tracking/gnuradio_blocks/glonass_l1_ca_dll_pll_c_aid_tracking_sc.cc

@@ -47,10 +47,10 @@
 #include <glog/logging.h>
 #include <gnuradio/io_signature.h>
 #include <matio.h>
+#include <pmt/pmt.h>
 #include <cmath>
 #include <iostream>
 #include <memory>
-#include <pmt/pmt.h>
 #include <sstream>
 #include <utility>
 

src/algorithms/tracking/gnuradio_blocks/glonass_l2_ca_dll_pll_c_aid_tracking_cc.cc

@@ -45,11 +45,11 @@
 #include <glog/logging.h>
 #include <gnuradio/io_signature.h>
 #include <matio.h>
+#include <pmt/pmt.h>
 #include <volk_gnsssdr/volk_gnsssdr.h>
 #include <cmath>
 #include <iostream>
 #include <memory>
-#include <pmt/pmt.h>
 #include <sstream>
 #include <utility>
 

src/algorithms/tracking/gnuradio_blocks/glonass_l2_ca_dll_pll_c_aid_tracking_cc.h

@@ -43,10 +43,10 @@
 //#include "tracking_loop_filter.h"
 #include "cpu_multicorrelator.h"
 #include <gnuradio/block.h>
+#include <pmt/pmt.h>
 #include <deque>
 #include <fstream>
 #include <map>
-#include <pmt/pmt.h>
 #include <string>
 
 class glonass_l2_ca_dll_pll_c_aid_tracking_cc;

src/algorithms/tracking/gnuradio_blocks/glonass_l2_ca_dll_pll_c_aid_tracking_sc.cc

@@ -45,10 +45,10 @@
 #include <glog/logging.h>
 #include <gnuradio/io_signature.h>
 #include <matio.h>
+#include <pmt/pmt.h>
 #include <cmath>
 #include <iostream>
 #include <memory>
-#include <pmt/pmt.h>
 #include <sstream>
 #include <utility>
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_cc.h

@@ -43,10 +43,10 @@
 //#include "tracking_loop_filter.h"
 #include "cpu_multicorrelator.h"
 #include <gnuradio/block.h>
+#include <pmt/pmt.h>
 #include <deque>
 #include <fstream>
 #include <map>
-#include <pmt/pmt.h>
 #include <string>
 
 class gps_l1_ca_dll_pll_c_aid_tracking_cc;

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_sc.cc

@@ -39,10 +39,10 @@
 #include <glog/logging.h>
 #include <gnuradio/io_signature.h>
 #include <matio.h>
+#include <pmt/pmt.h>
 #include <cmath>
 #include <iostream>
 #include <memory>
-#include <pmt/pmt.h>
 #include <sstream>
 #include <utility>
 

src/core/interfaces/acquisition_interface.h

@@ -65,6 +65,7 @@ public:
     virtual signed int mag() = 0;
     virtual void reset() = 0;
     virtual void stop_acquisition() = 0;
+    virtual void set_resampler_latency(uint32_t latency_samples) = 0;
 };
 
 #endif /* GNSS_SDR_ACQUISITION_INTERFACE */

src/core/interfaces/channel_interface.h

@@ -51,6 +51,10 @@
 class ChannelInterface : public GNSSBlockInterface
 {
 public:
+    virtual gr::basic_block_sptr get_left_block_trk() = 0;
+    virtual gr::basic_block_sptr get_left_block_acq() = 0;
+    virtual gr::basic_block_sptr get_left_block() = 0;
+    virtual gr::basic_block_sptr get_right_block() = 0;
     virtual Gnss_Signal get_signal() const = 0;
     virtual void start_acquisition() = 0;
     virtual void stop_channel() = 0;

src/core/receiver/gnss_block_factory.cc

@@ -360,12 +360,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_1C(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(config, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_1C" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_1C" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_1C" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),
@@ -425,12 +424,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_2S(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(configuration, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_2S" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_2S" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_2S" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),
@@ -493,12 +491,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_1B(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(configuration, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_1B" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_1B" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_1B" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),
@@ -561,12 +558,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_5X(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(configuration, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_5X" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_5X" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_5X" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),
@@ -630,12 +626,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_1G(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(config, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_1G" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_1G" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_1G" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),
@@ -699,12 +694,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_2G(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(config, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_2G" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_2G" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_2G" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),
@@ -767,12 +761,11 @@ std::unique_ptr<GNSSBlockInterface> GNSSBlockFactory::GetChannel_L5(
         }
     config->set_property("Channel.item_type", acq_item_type);
 
-    std::unique_ptr<GNSSBlockInterface> pass_through_ = GetBlock(configuration, "Channel", "Pass_Through", 1, 1, queue);
     std::unique_ptr<AcquisitionInterface> acq_ = GetAcqBlock(configuration, "Acquisition_L5" + appendix1, acq, 1, 0);
     std::unique_ptr<TrackingInterface> trk_ = GetTrkBlock(configuration, "Tracking_L5" + appendix2, trk, 1, 1);
     std::unique_ptr<TelemetryDecoderInterface> tlm_ = GetTlmBlock(configuration, "TelemetryDecoder_L5" + appendix3, tlm, 1, 1);
 
-    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel, std::move(pass_through_),
+    std::unique_ptr<GNSSBlockInterface> channel_(new Channel(configuration.get(), channel,
         std::move(acq_),
         std::move(trk_),
         std::move(tlm_),

src/core/receiver/gnss_flowgraph.cc

@@ -33,18 +33,28 @@
  */
 
 #include "gnss_flowgraph.h"
+#include "GPS_L1_CA.h"
+#include "GPS_L2C.h"
+#include "GPS_L5.h"
+#include "Galileo_E1.h"
+#include "Galileo_E5a.h"
+#include "channel.h"
 #include "channel_interface.h"
 #include "configuration_interface.h"
 #include "gnss_block_factory.h"
-#include "gnss_block_interface.h"
-#include "gnss_synchro.h"
 #include <boost/lexical_cast.hpp>
 #include <boost/tokenizer.hpp>
 #include <glog/logging.h>
+#include <gnuradio/filter/firdes.h>
 #include <algorithm>
 #include <exception>
 #include <iostream>
 #include <set>
+#ifdef GR_GREATER_38
+#include <gnuradio/filter/fir_filter_blk.h>
+#else
+#include <gnuradio/filter/fir_filter_ccf.h>
+#endif
 
 
 #define GNSS_SDR_ARRAY_SIGNAL_CONDITIONER_CHANNELS 8
@@ -343,6 +353,8 @@ void GNSSFlowgraph::connect()
 #endif
     // Signal conditioner (selected_signal_source) >> channels (i) (dependent of their associated SignalSource_ID)
     int selected_signal_conditioner_ID = 0;
+    bool use_acq_resampler = configuration_->property("GNSS-SDR.use_acquisition_resampler", false);
+    uint32_t fs = configuration_->property("GNSS-SDR.internal_fs_sps", 0);
     for (unsigned int i = 0; i < channels_count_; i++)
         {
             if (FPGA_enabled == false)
@@ -357,8 +369,119 @@ void GNSSFlowgraph::connect()
                         }
                     try
                         {
-                            top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                            // Enable automatic resampler for the acquisition, if required
-                                channels_.at(i)->get_left_block(), 0);
+                            if (use_acq_resampler == true)
+                                {
+                                    //create acquisition resamplers if required
+                                    double resampler_ratio = 1.0;
+                                    double acq_fs = fs;
+                                    //find the signal associated to this channel
+                                    switch (mapStringValues_[channels_.at(i)->implementation()])
+                                        {
+                                        case evGPS_1C:
+                                            acq_fs = GPS_L1_CA_OPT_ACQ_FS_HZ;
+                                            break;
+                                        case evGPS_2S:
+                                            acq_fs = GPS_L2C_OPT_ACQ_FS_HZ;
+                                            break;
+                                        case evGPS_L5:
+                                            acq_fs = GPS_L5_OPT_ACQ_FS_HZ;
+                                            break;
+                                        case evSBAS_1C:
+                                            acq_fs = GPS_L1_CA_OPT_ACQ_FS_HZ;
+                                            break;
+                                        case evGAL_1B:
+                                            acq_fs = Galileo_E1_OPT_ACQ_FS_HZ;
+                                            break;
+                                        case evGAL_5X:
+                                            acq_fs = Galileo_E5a_OPT_ACQ_FS_HZ;
+                                            break;
+                                        case evGLO_1G:
+                                            acq_fs = fs;
+                                            break;
+                                        case evGLO_2G:
+                                            acq_fs = fs;
+                                            break;
+                                        }
+
+                                    if (acq_fs < fs)
+                                        {
+                                            //check if the resampler is already created for the channel system/signal and for the specific RF Channel
+                                            std::string map_key = channels_.at(i)->implementation() + std::to_string(selected_signal_conditioner_ID);
+                                            resampler_ratio = static_cast<double>(fs) / acq_fs;
+                                            int decimation = floor(resampler_ratio);
+                                            while (fs % decimation > 0)
+                                                {
+                                                    decimation--;
+                                                };
+                                            double acq_fs = fs / decimation;
+
+                                            if (decimation > 1)
+                                                {
+                                                    //create a FIR low pass filter
+                                                    std::vector<float> taps;
+                                                    taps = gr::filter::firdes::low_pass(1.0,
+                                                        fs,
+                                                        acq_fs / 2.1,
+                                                        acq_fs / 10,
+                                                        gr::filter::firdes::win_type::WIN_HAMMING);
+
+                                                    gr::basic_block_sptr fir_filter_ccf_ = gr::filter::fir_filter_ccf::make(decimation, taps);
+
+                                                    std::pair<std::map<std::string, gr::basic_block_sptr>::iterator, bool> ret;
+                                                    ret = acq_resamplers_.insert(std::pair<std::string, gr::basic_block_sptr>(map_key, fir_filter_ccf_));
+                                                    if (ret.second == true)
+                                                        {
+                                                            top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                                                acq_resamplers_.at(map_key), 0);
+                                                            LOG(INFO) << "Created "
+                                                                      << channels_.at(i)->implementation()
+                                                                      << " acquisition resampler for RF channel " << std::to_string(signal_conditioner_ID) << " with " << taps.size() << " taps and decimation factor of " << decimation;
+                                                        }
+                                                    else
+                                                        {
+                                                            LOG(INFO) << "Found existing "
+                                                                      << channels_.at(i)->implementation()
+                                                                      << " acquisition resampler for RF channel " << std::to_string(signal_conditioner_ID) << " with " << taps.size() << " taps and decimation factor of " << decimation;
+                                                        }
+
+
+                                                    top_block_->connect(acq_resamplers_.at(map_key), 0,
+                                                        channels_.at(i)->get_left_block_acq(), 0);
+
+                                                    top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                                        channels_.at(i)->get_left_block_trk(), 0);
+
+                                                    std::shared_ptr<Channel> channel_ptr;
+                                                    channel_ptr = std::dynamic_pointer_cast<Channel>(channels_.at(i));
+                                                    channel_ptr->acquisition()->set_resampler_latency((taps.size() - 1) / 2);
+                                                }
+                                            else
+                                                {
+                                                    LOG(INFO) << "Disabled acquisition resampler because the input sampling frequency is too low";
+                                                    //resampler not required!
+                                                    top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                                        channels_.at(i)->get_left_block_acq(), 0);
+                                                    top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                                        channels_.at(i)->get_left_block_trk(), 0);
+                                                }
+                                        }
+                                    else
+                                        {
+                                            LOG(INFO) << "Disabled acquisition resampler because the input sampling frequency is too low";
+                                            top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                                channels_.at(i)->get_left_block_acq(), 0);
+                                            top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                                channels_.at(i)->get_left_block_trk(), 0);
+                                        }
+                                }
+                            else
+                                {
+                                    top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                        channels_.at(i)->get_left_block_acq(), 0);
+                                    top_block_->connect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
+                                        channels_.at(i)->get_left_block_trk(), 0);
+                                }
                         }
                     catch (const std::exception& e)
                         {
@@ -678,7 +801,7 @@ void GNSSFlowgraph::disconnect()
             try
                 {
                     top_block_->disconnect(sig_conditioner_.at(selected_signal_conditioner_ID)->get_right_block(), 0,
-                        channels_.at(i)->get_left_block(), 0);
+                        channels_.at(i)->get_left_block_trk(), 0);
                 }
             catch (const std::exception& e)
                 {

src/core/receiver/gnss_flowgraph.h

@@ -55,6 +55,7 @@
 #include <queue>
 #include <string>
 #include <vector>
+#include <map>
 
 #if ENABLE_FPGA
 #include "gnss_sdr_fpga_sample_counter.h"
@@ -166,6 +167,7 @@ private:
     std::shared_ptr<GNSSBlockInterface> observables_;
     std::shared_ptr<GNSSBlockInterface> pvt_;
 
+    std::map<std::string, gr::basic_block_sptr> acq_resamplers_;
     std::vector<std::shared_ptr<ChannelInterface>> channels_;
     gnss_sdr_sample_counter_sptr ch_out_sample_counter;
 #if ENABLE_FPGA

src/core/system_parameters/GPS_L1_CA.h

@@ -57,6 +57,9 @@ const double GPS_L1_CA_CODE_PERIOD = 0.001;         //!< GPS L1 C/A code period
 const uint32_t GPS_L1_CA_CODE_PERIOD_MS = 1U;       //!< GPS L1 C/A code period [ms]
 const double GPS_L1_CA_CHIP_PERIOD = 9.7752e-07;    //!< GPS L1 C/A chip period [seconds]
 
+//optimum parameters
+const uint32_t GPS_L1_CA_OPT_ACQ_FS_HZ = 1000000;  //!< Sampling frequncy that maximizes the acquisition SNR while using a non-multiple of chip rate
+
 /*!
  * \brief Maximum Time-Of-Arrival (TOA) difference between satellites for a receiver operated on Earth surface is 20 ms
  *

src/core/system_parameters/GPS_L2C.h

@@ -63,6 +63,10 @@ const double GPS_L2_L_PERIOD = 1.5;                 //!< GPS L2 L code period [s
 
 const int32_t GPS_L2C_HISTORY_DEEP = 5;
 
+//optimum parameters
+const uint32_t GPS_L2C_OPT_ACQ_FS_HZ = 1000000;  //!< Sampling frequncy that maximizes the acquisition SNR while using a non-multiple of chip rate
+
+
 const int32_t GPS_L2C_M_INIT_REG[115] =
     {0742417664, 0756014035, 0002747144, 0066265724,     // 1:4
         0601403471, 0703232733, 0124510070, 0617316361,  // 5:8

src/core/system_parameters/GPS_L5.h

@@ -64,6 +64,9 @@ const double GPS_L5q_PERIOD = 0.001;              //!< GPS L5 code period [secon
 
 const int32_t GPS_L5_HISTORY_DEEP = 5;
 
+//optimum parameters
+const uint32_t GPS_L5_OPT_ACQ_FS_HZ = 10000000;  //!< Sampling frequncy that maximizes the acquisition SNR while using a non-multiple of chip rate
+
 const int32_t GPS_L5i_INIT_REG[210] =
     {266, 365, 804, 1138,
         1509, 1559, 1756, 2084,

src/core/system_parameters/Galileo_E1.h

@@ -63,6 +63,11 @@ const int32_t Galileo_E1_B_SAMPLES_PER_SYMBOL = 1;        //!< (Galileo_E1_CODE_
 const int32_t Galileo_E1_C_SECONDARY_CODE_LENGTH = 25;    //!< Galileo E1-C secondary code length [chips]
 const int32_t Galileo_E1_NUMBER_OF_CODES = 50;
 
+
+//optimum parameters
+const uint32_t Galileo_E1_OPT_ACQ_FS_HZ = 2000000;  //!< Sampling frequncy that maximizes the acquisition SNR while using a non-multiple of chip rate
+
+
 const double GALILEO_STARTOFFSET_ms = 68.802;  //[ms] Initial sign. travel time (this cannot go here)
 
 

src/core/system_parameters/Galileo_E5a.h

@@ -57,6 +57,9 @@ const int32_t Galileo_E5a_NUMBER_OF_CODES = 50;
 const int32_t GALILEO_E5A_HISTORY_DEEP = 20;
 const int32_t GALILEO_E5A_CRC_ERROR_LIMIT = 6;
 
+//optimum parameters
+const uint32_t Galileo_E5a_OPT_ACQ_FS_HZ = 10000000;  //!< Sampling frequncy that maximizes the acquisition SNR while using a non-multiple of chip rate
+
 // F/NAV message structure
 
 const int32_t GALILEO_FNAV_PREAMBLE_LENGTH_BITS = 12;

src/tests/common-files/tracking_tests_flags.h

@@ -42,6 +42,7 @@ DEFINE_double(external_signal_acquisition_threshold, 2.5, "Threshold for satelli
 DEFINE_int32(external_signal_acquisition_dwells, 5, "Maximum dwells count for satellite acquisition when external file is used");
 DEFINE_double(external_signal_acquisition_doppler_max_hz, 5000.0, "Doppler max for satellite acquisition when external file is used");
 DEFINE_double(external_signal_acquisition_doppler_step_hz, 125.0, "Doppler step for satellite acquisition when external file is used");
+DEFINE_bool(use_acquisition_resampler, false, "Reduce the sampling rate of the input signal for the acquisition in order to optimize the SNR and decrease the processor load");
 
 DEFINE_string(signal_file, std::string("signal_out.bin"), "Path of the external signal capture file");
 DEFINE_double(CN0_dBHz_start, std::numeric_limits<double>::infinity(), "Enable noise generator and set the CN0 start sweep value [dB-Hz]");

src/tests/system-tests/position_test.cc

@@ -33,6 +33,7 @@
  */
 
 #include "MATH_CONSTANTS.h"
+#include "acquisition_msg_rx.h"
 #include "concurrent_map.h"
 #include "concurrent_queue.h"
 #include "control_thread.h"
@@ -45,6 +46,7 @@
 #include "signal_generator_flags.h"
 #include "spirent_motion_csv_dump_reader.h"
 #include "test_flags.h"
+#include "tracking_tests_flags.h"  //acquisition resampler
 #include <armadillo>
 #include <boost/filesystem.hpp>
 #include <glog/logging.h>
@@ -183,6 +185,11 @@ int PositionSystemTest::configure_receiver()
             const int output_rate_ms = 100;
 
             config->set_property("GNSS-SDR.internal_fs_sps", std::to_string(sampling_rate_internal));
+            // Enable automatic resampler for the acquisition, if required
+            if (FLAGS_use_acquisition_resampler == true)
+                {
+                    config->set_property("GNSS-SDR.use_acquisition_resampler", "true");
+                }
 
             // Set the assistance system parameters
             config->set_property("GNSS-SDR.SUPL_read_gps_assistance_xml", "false");

src/tests/unit-tests/signal-processing-blocks/observables/hybrid_observables_test.cc

@@ -31,6 +31,10 @@
  */
 
 #include "GPS_L1_CA.h"
+#include "GPS_L2C.h"
+#include "GPS_L5.h"
+#include "Galileo_E1.h"
+#include "Galileo_E5a.h"
 #include "acquisition_msg_rx.h"
 #include "galileo_e1_pcps_ambiguous_acquisition.h"
 #include "galileo_e5a_noncoherent_iq_acquisition_caf.h"
@@ -64,6 +68,7 @@
 #include <gnuradio/blocks/file_source.h>
 #include <gnuradio/blocks/interleaved_char_to_complex.h>
 #include <gnuradio/blocks/null_sink.h>
+#include <gnuradio/filter/firdes.h>
 #include <gnuradio/top_block.h>
 #include <gtest/gtest.h>
 #include <matio.h>
@@ -75,6 +80,11 @@
 #include <gpstk/Rinex3ObsStream.hpp>
 #include <gpstk/RinexUtilities.hpp>
 #include <unistd.h>
+#ifdef GR_GREATER_38
+#include <gnuradio/filter/fir_filter_blk.h>
+#else
+#include <gnuradio/filter/fir_filter_ccf.h>
+#endif
 
 
 // ######## GNURADIO BLOCK MESSAGE RECEVER FOR TRACKING MESSAGES #########
@@ -186,6 +196,19 @@ HybridObservablesTest_tlm_msg_rx::~HybridObservablesTest_tlm_msg_rx()
 class HybridObservablesTest : public ::testing::Test
 {
 public:
+    enum StringValue
+    {
+        evGPS_1C,
+        evGPS_2S,
+        evGPS_L5,
+        evSBAS_1C,
+        evGAL_1B,
+        evGAL_5X,
+        evGLO_1G,
+        evGLO_2G
+    };
+    std::map<std::string, StringValue> mapStringValues_;
+
     std::string generator_binary;
     std::string p1;
     std::string p2;
@@ -247,6 +270,13 @@ public:
         factory = std::make_shared<GNSSBlockFactory>();
         config = std::make_shared<InMemoryConfiguration>();
         item_size = sizeof(gr_complex);
+        mapStringValues_["1C"] = evGPS_1C;
+        mapStringValues_["2S"] = evGPS_2S;
+        mapStringValues_["L5"] = evGPS_L5;
+        mapStringValues_["1B"] = evGAL_1B;
+        mapStringValues_["5X"] = evGAL_5X;
+        mapStringValues_["1G"] = evGLO_1G;
+        mapStringValues_["2G"] = evGLO_2G;
     }
 
     ~HybridObservablesTest()
@@ -328,6 +358,11 @@ bool HybridObservablesTest::acquire_signal()
     tmp_gnss_synchro.Channel_ID = 0;
     config = std::make_shared<InMemoryConfiguration>();
     config->set_property("GNSS-SDR.internal_fs_sps", std::to_string(baseband_sampling_freq));
+    // Enable automatic resampler for the acquisition, if required
+    if (FLAGS_use_acquisition_resampler == true)
+        {
+            config->set_property("GNSS-SDR.use_acquisition_resampler", "true");
+        }
     config->set_property("Acquisition.blocking_on_standby", "true");
     config->set_property("Acquisition.blocking", "true");
     config->set_property("Acquisition.dump", "false");
@@ -337,11 +372,12 @@ bool HybridObservablesTest::acquire_signal()
     std::shared_ptr<AcquisitionInterface> acquisition;
 
     std::string System_and_Signal;
+    std::string signal;
     //create the correspondign acquisition block according to the desired tracking signal
     if (implementation.compare("GPS_L1_CA_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'G';
-            std::string signal = "1C";
+            signal = "1C";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -353,7 +389,7 @@ bool HybridObservablesTest::acquire_signal()
     else if (implementation.compare("Galileo_E1_DLL_PLL_VEML_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'E';
-            std::string signal = "1B";
+            signal = "1B";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -364,7 +400,7 @@ bool HybridObservablesTest::acquire_signal()
     else if (implementation.compare("GPS_L2_M_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'G';
-            std::string signal = "2S";
+            signal = "2S";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -375,7 +411,7 @@ bool HybridObservablesTest::acquire_signal()
     else if (implementation.compare("Galileo_E5a_DLL_PLL_Tracking_b") == 0)
         {
             tmp_gnss_synchro.System = 'E';
-            std::string signal = "5X";
+            signal = "5X";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -391,7 +427,7 @@ bool HybridObservablesTest::acquire_signal()
     else if (implementation.compare("Galileo_E5a_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'E';
-            std::string signal = "5X";
+            signal = "5X";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -402,7 +438,7 @@ bool HybridObservablesTest::acquire_signal()
     else if (implementation.compare("GPS_L5_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'G';
-            std::string signal = "L5";
+            signal = "L5";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -433,10 +469,88 @@ bool HybridObservablesTest::acquire_signal()
     file_source->seek(2 * FLAGS_skip_samples, 0);  //skip head. ibyte, two bytes per complex sample
     gr::blocks::interleaved_char_to_complex::sptr gr_interleaved_char_to_complex = gr::blocks::interleaved_char_to_complex::make();
     //gr::blocks::head::sptr head_samples = gr::blocks::head::make(sizeof(gr_complex), baseband_sampling_freq * FLAGS_duration);
+    //top_block->connect(head_samples, 0, acquisition->get_left_block(), 0);
 
     top_block->connect(file_source, 0, gr_interleaved_char_to_complex, 0);
-    top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+
-    //top_block->connect(head_samples, 0, acquisition->get_left_block(), 0);
+    // Enable automatic resampler for the acquisition, if required
+    if (FLAGS_use_acquisition_resampler == true)
+        {
+            //create acquisition resamplers if required
+            double resampler_ratio = 1.0;
+
+            double opt_fs = baseband_sampling_freq;
+            //find the signal associated to this channel
+            switch (mapStringValues_[signal])
+                {
+                case evGPS_1C:
+                    opt_fs = GPS_L1_CA_OPT_ACQ_FS_HZ;
+                    break;
+                case evGPS_2S:
+                    opt_fs = GPS_L2C_OPT_ACQ_FS_HZ;
+                    break;
+                case evGPS_L5:
+                    opt_fs = GPS_L5_OPT_ACQ_FS_HZ;
+                    break;
+                case evSBAS_1C:
+                    opt_fs = GPS_L1_CA_OPT_ACQ_FS_HZ;
+                    break;
+                case evGAL_1B:
+                    opt_fs = Galileo_E1_OPT_ACQ_FS_HZ;
+                    break;
+                case evGAL_5X:
+                    opt_fs = Galileo_E5a_OPT_ACQ_FS_HZ;
+                    break;
+                case evGLO_1G:
+                    opt_fs = baseband_sampling_freq;
+                    break;
+                case evGLO_2G:
+                    opt_fs = baseband_sampling_freq;
+                    break;
+                }
+            if (opt_fs < baseband_sampling_freq)
+                {
+                    resampler_ratio = baseband_sampling_freq / opt_fs;
+                    int decimation = floor(resampler_ratio);
+                    while (baseband_sampling_freq % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    double acq_fs = baseband_sampling_freq / decimation;
+
+                    if (decimation > 1)
+                        {
+                            //create a FIR low pass filter
+                            std::vector<float> taps;
+                            taps = gr::filter::firdes::low_pass(1.0,
+                                baseband_sampling_freq,
+                                acq_fs / 2.1,
+                                acq_fs / 10,
+                                gr::filter::firdes::win_type::WIN_HAMMING);
+                            std::cout << "Enabled decimation low pass filter with " << taps.size() << " taps and decimation factor of " << decimation << std::endl;
+                            acquisition->set_resampler_latency((taps.size() - 1) / 2);
+                            gr::basic_block_sptr fir_filter_ccf_ = gr::filter::fir_filter_ccf::make(decimation, taps);
+                            top_block->connect(gr_interleaved_char_to_complex, 0, fir_filter_ccf_, 0);
+                            top_block->connect(fir_filter_ccf_, 0, acquisition->get_left_block(), 0);
+                        }
+                    else
+                        {
+                            std::cout << "Disabled acquisition resampler because the input sampling frequency is too low\n";
+                            top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+                        }
+                }
+            else
+                {
+                    std::cout << "Disabled acquisition resampler because the input sampling frequency is too low\n";
+                    top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+                }
+        }
+    else
+        {
+            top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+            //top_block->connect(head_samples, 0, acquisition->get_left_block(), 0);
+        }
+
 
     boost::shared_ptr<Acquisition_msg_rx> msg_rx;
     try

src/tests/unit-tests/signal-processing-blocks/tracking/tracking_pull-in_test.cc

@@ -30,8 +30,11 @@
  * -------------------------------------------------------------------------
  */
 
-
 #include "GPS_L1_CA.h"
+#include "GPS_L2C.h"
+#include "GPS_L5.h"
+#include "Galileo_E1.h"
+#include "Galileo_E5a.h"
 #include "acquisition_msg_rx.h"
 #include "control_message_factory.h"
 #include "galileo_e1_pcps_ambiguous_acquisition.h"
@@ -58,12 +61,18 @@
 #include <gnuradio/blocks/interleaved_char_to_complex.h>
 #include <gnuradio/blocks/null_sink.h>
 #include <gnuradio/blocks/skiphead.h>
+#include <gnuradio/filter/firdes.h>
 #include <gnuradio/msg_queue.h>
 #include <gnuradio/top_block.h>
 #include <gtest/gtest.h>
 #include <chrono>
 #include <cstdint>
 #include <vector>
+#ifdef GR_GREATER_38
+#include <gnuradio/filter/fir_filter_blk.h>
+#else
+#include <gnuradio/filter/fir_filter_ccf.h>
+#endif
 
 
 // ######## GNURADIO TRACKING BLOCK MESSAGE RECEVER #########
@@ -126,6 +135,19 @@ TrackingPullInTest_msg_rx::~TrackingPullInTest_msg_rx()
 class TrackingPullInTest : public ::testing::Test
 {
 public:
+    enum StringValue
+    {
+        evGPS_1C,
+        evGPS_2S,
+        evGPS_L5,
+        evSBAS_1C,
+        evGAL_1B,
+        evGAL_5X,
+        evGLO_1G,
+        evGLO_2G
+    };
+    std::map<std::string, StringValue> mapStringValues_;
+
     std::string generator_binary;
     std::string p1;
     std::string p2;
@@ -171,6 +193,13 @@ public:
         config = std::make_shared<InMemoryConfiguration>();
         item_size = sizeof(gr_complex);
         gnss_synchro = Gnss_Synchro();
+        mapStringValues_["1C"] = evGPS_1C;
+        mapStringValues_["2S"] = evGPS_2S;
+        mapStringValues_["L5"] = evGPS_L5;
+        mapStringValues_["1B"] = evGAL_1B;
+        mapStringValues_["5X"] = evGAL_5X;
+        mapStringValues_["1G"] = evGLO_1G;
+        mapStringValues_["2G"] = evGLO_2G;
     }
 
     ~TrackingPullInTest()
@@ -289,7 +318,7 @@ void TrackingPullInTest::configure_receiver(
             System_and_Signal = "GPS L2CM";
             signal.copy(gnss_synchro.Signal, 2, 0);
             config->set_property("Tracking.early_late_space_chips", "0.5");
-            config->set_property("Tracking.track_pilot", "false");
+            config->set_property("Tracking.track_pilot", "true");
         }
     else if (implementation.compare("Galileo_E5a_DLL_PLL_Tracking") == 0 or implementation.compare("Galileo_E5a_DLL_PLL_Tracking_b") == 0)
         {
@@ -302,7 +331,7 @@ void TrackingPullInTest::configure_receiver(
                     config->supersede_property("Tracking.implementation", std::string("Galileo_E5a_DLL_PLL_Tracking"));
                 }
             config->set_property("Tracking.early_late_space_chips", "0.5");
-            config->set_property("Tracking.track_pilot", "false");
+            config->set_property("Tracking.track_pilot", "true");
             config->set_property("Tracking.order", "2");
         }
     else if (implementation.compare("GPS_L5_DLL_PLL_Tracking") == 0)
@@ -312,7 +341,7 @@ void TrackingPullInTest::configure_receiver(
             System_and_Signal = "GPS L5I";
             signal.copy(gnss_synchro.Signal, 2, 0);
             config->set_property("Tracking.early_late_space_chips", "0.5");
-            config->set_property("Tracking.track_pilot", "false");
+            config->set_property("Tracking.track_pilot", "true");
             config->set_property("Tracking.order", "2");
         }
     else
@@ -345,8 +374,15 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     // Satellite signal definition
     Gnss_Synchro tmp_gnss_synchro;
     tmp_gnss_synchro.Channel_ID = 0;
+
+
     config = std::make_shared<InMemoryConfiguration>();
     config->set_property("GNSS-SDR.internal_fs_sps", std::to_string(baseband_sampling_freq));
+    // Enable automatic resampler for the acquisition, if required
+    if (FLAGS_use_acquisition_resampler == true)
+        {
+            config->set_property("GNSS-SDR.use_acquisition_resampler", "true");
+        }
     config->set_property("Acquisition.blocking_on_standby", "true");
     config->set_property("Acquisition.blocking", "true");
     config->set_property("Acquisition.dump", "false");
@@ -356,11 +392,12 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     std::shared_ptr<AcquisitionInterface> acquisition;
 
     std::string System_and_Signal;
+    std::string signal;
     //create the correspondign acquisition block according to the desired tracking signal
     if (implementation.compare("GPS_L1_CA_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'G';
-            std::string signal = "1C";
+            signal = "1C";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -372,7 +409,7 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     else if (implementation.compare("Galileo_E1_DLL_PLL_VEML_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'E';
-            std::string signal = "1B";
+            signal = "1B";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -383,7 +420,7 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     else if (implementation.compare("GPS_L2_M_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'G';
-            std::string signal = "2S";
+            signal = "2S";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -394,7 +431,7 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     else if (implementation.compare("Galileo_E5a_DLL_PLL_Tracking_b") == 0)
         {
             tmp_gnss_synchro.System = 'E';
-            std::string signal = "5X";
+            signal = "5X";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -410,7 +447,7 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     else if (implementation.compare("Galileo_E5a_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'E';
-            std::string signal = "5X";
+            signal = "5X";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -421,7 +458,7 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     else if (implementation.compare("GPS_L5_DLL_PLL_Tracking") == 0)
         {
             tmp_gnss_synchro.System = 'G';
-            std::string signal = "L5";
+            signal = "L5";
             const char* str = signal.c_str();                                  // get a C style null terminated string
             std::memcpy(static_cast<void*>(tmp_gnss_synchro.Signal), str, 3);  // copy string into synchro char array: 2 char + null
             tmp_gnss_synchro.PRN = SV_ID;
@@ -449,13 +486,90 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
     std::string file = FLAGS_signal_file;
     const char* file_name = file.c_str();
     file_source = gr::blocks::file_source::make(sizeof(int8_t), file_name, false);
-    file_source->seek(2 * FLAGS_skip_samples, 0);  //skip head. ibyte, two bytes per complex sample
+    file_source->seek(2 * FLAGS_skip_samples, SEEK_SET);  //skip head. ibyte, two bytes per complex sample
     gr::blocks::interleaved_char_to_complex::sptr gr_interleaved_char_to_complex = gr::blocks::interleaved_char_to_complex::make();
     //gr::blocks::head::sptr head_samples = gr::blocks::head::make(sizeof(gr_complex), baseband_sampling_freq * FLAGS_duration);
 
     top_block->connect(file_source, 0, gr_interleaved_char_to_complex, 0);
-    top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+
-    //top_block->connect(head_samples, 0, acquisition->get_left_block(), 0);
+    // Enable automatic resampler for the acquisition, if required
+    if (FLAGS_use_acquisition_resampler == true)
+        {
+            //create acquisition resamplers if required
+            double resampler_ratio = 1.0;
+
+            double opt_fs = baseband_sampling_freq;
+            //find the signal associated to this channel
+            switch (mapStringValues_[signal])
+                {
+                case evGPS_1C:
+                    opt_fs = GPS_L1_CA_OPT_ACQ_FS_HZ;
+                    break;
+                case evGPS_2S:
+                    opt_fs = GPS_L2C_OPT_ACQ_FS_HZ;
+                    break;
+                case evGPS_L5:
+                    opt_fs = GPS_L5_OPT_ACQ_FS_HZ;
+                    break;
+                case evSBAS_1C:
+                    opt_fs = GPS_L1_CA_OPT_ACQ_FS_HZ;
+                    break;
+                case evGAL_1B:
+                    opt_fs = Galileo_E1_OPT_ACQ_FS_HZ;
+                    break;
+                case evGAL_5X:
+                    opt_fs = Galileo_E5a_OPT_ACQ_FS_HZ;
+                    break;
+                case evGLO_1G:
+                    opt_fs = baseband_sampling_freq;
+                    break;
+                case evGLO_2G:
+                    opt_fs = baseband_sampling_freq;
+                    break;
+                }
+            if (opt_fs < baseband_sampling_freq)
+                {
+                    resampler_ratio = baseband_sampling_freq / opt_fs;
+                    int decimation = floor(resampler_ratio);
+                    while (baseband_sampling_freq % decimation > 0)
+                        {
+                            decimation--;
+                        };
+                    double acq_fs = baseband_sampling_freq / decimation;
+
+                    if (decimation > 1)
+                        {
+                            //create a FIR low pass filter
+                            std::vector<float> taps;
+                            taps = gr::filter::firdes::low_pass(1.0,
+                                baseband_sampling_freq,
+                                acq_fs / 2.1,
+                                acq_fs / 10,
+                                gr::filter::firdes::win_type::WIN_HAMMING);
+                            std::cout << "Enabled decimation low pass filter with " << taps.size() << " taps and decimation factor of " << decimation << std::endl;
+                            acquisition->set_resampler_latency((taps.size() - 1) / 2);
+                            gr::basic_block_sptr fir_filter_ccf_ = gr::filter::fir_filter_ccf::make(decimation, taps);
+                            top_block->connect(gr_interleaved_char_to_complex, 0, fir_filter_ccf_, 0);
+                            top_block->connect(fir_filter_ccf_, 0, acquisition->get_left_block(), 0);
+                        }
+                    else
+                        {
+                            std::cout << "Disabled acquisition resampler because the input sampling frequency is too low\n";
+                            top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+                        }
+                }
+            else
+                {
+                    std::cout << "Disabled acquisition resampler because the input sampling frequency is too low\n";
+                    top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+                }
+        }
+    else
+        {
+            top_block->connect(gr_interleaved_char_to_complex, 0, acquisition->get_left_block(), 0);
+            //top_block->connect(head_samples, 0, acquisition->get_left_block(), 0);
+        }
+
 
     boost::shared_ptr<Acquisition_msg_rx> msg_rx;
     try
@@ -531,7 +645,7 @@ bool TrackingPullInTest::acquire_signal(int SV_ID)
                     std::cout << " . ";
                 }
             top_block->stop();
-            file_source->seek(2 * FLAGS_skip_samples, 0);  //skip head. ibyte, two bytes per complex sample
+            file_source->seek(2 * FLAGS_skip_samples, SEEK_SET);  //skip head. ibyte, two bytes per complex sample
             std::cout.flush();
         }
     std::cout << "]" << std::endl;