Implementation of a missing output decimation for the Galileo E1

telemetry
decoder block

src/algorithms/telemetry_decoder/adapters/galileo_e1b_telemetry_decoder.cc

@@ -76,6 +76,11 @@ GalileoE1BTelemetryDecoder::GalileoE1BTelemetryDecoder(ConfigurationInterface* c
     telemetry_decoder_->set_iono_queue(&global_galileo_iono_queue);
     telemetry_decoder_->set_almanac_queue(&global_galileo_almanac_queue);
     telemetry_decoder_->set_utc_model_queue(&global_galileo_utc_model_queue);
+
+    //decimation factor
+    int decimation_factor = configuration->property(role + ".decimation_factor", 1);
+    telemetry_decoder_->set_decimation(decimation_factor);
+
     channel_ = 0;
 }
 

src/algorithms/telemetry_decoder/gnuradio_blocks/galileo_e1b_telemetry_decoder_cc.cc

@@ -180,6 +180,8 @@ galileo_e1b_telemetry_decoder_cc::galileo_e1b_telemetry_decoder_cc(
     d_channel = 0;
     Prn_timestamp_at_preamble_ms = 0.0;
     flag_TOW_set = false;
+    d_average_count = 0;
+    d_decimation_output_factor = 1;
 }
 
 
@@ -495,13 +497,29 @@ int galileo_e1b_telemetry_decoder_cc::general_work (int noutput_items, gr_vector
                     LOG(WARNING) << "Exception writing observables dump file " << e.what();
             }
         }
-    //3. Make the output (copy the object contents to the GNURadio reserved memory)
+    //todo: implement averaging
-    *out[0] = current_synchro_data;
+    d_average_count++;
+    if (d_average_count == d_decimation_output_factor)
+        {
+            d_average_count = 0;
+            //3. Make the output (copy the object contents to the GNURadio reserved memory)
+            *out[0] = current_synchro_data;
+            //std::cout<<"GPS L1 TLM output on CH="<<this->d_channel << " SAMPLE STAMP="<<d_sample_counter/d_decimation_output_factor<<std::endl;
+            return 1;
+        }
+    else
+        {
+            return 0;
+        }
 
-    return 1;
 }
 
 
+void galileo_e1b_telemetry_decoder_cc::set_decimation(int decimation)
+{
+    d_decimation_output_factor = decimation;
+}
+
 void galileo_e1b_telemetry_decoder_cc::set_satellite(Gnss_Satellite satellite)
 {
     d_satellite = Gnss_Satellite(satellite.get_system(), satellite.get_PRN());

src/algorithms/telemetry_decoder/gnuradio_blocks/galileo_e1b_telemetry_decoder_cc.h

@@ -72,6 +72,12 @@ public:
     void set_iono_queue(concurrent_queue<Galileo_Iono> *iono_queue);                //!< Set the iono data queue
     void set_almanac_queue(concurrent_queue<Galileo_Almanac> *almanac_queue);       //!< Set the almanac data queue
     void set_utc_model_queue(concurrent_queue<Galileo_Utc_Model> *utc_model_queue); //!< Set the UTC model queue
+
+    /*!
+     * \brief Set decimation factor to average the GPS synchronization estimation output from the tracking module.
+     */
+    void set_decimation(int decimation);
+
     /*!
      * \brief This is where all signal processing takes place
      */
@@ -132,6 +138,10 @@ private:
     Gnss_Satellite d_satellite;
     int d_channel;
 
+    // output averaging and decimation
+    int d_average_count;
+    int d_decimation_output_factor;
+
     double d_preamble_time_seconds;
 
     double d_TOW_at_Preamble;