Removing gnuradio output buffer request on observables and disabling the gnss_synchro output for all trackings that are not tracking any satellite. This is a bug fix to avoid gnuradio flowgraph deadlocks when different GNSS integration times are used in satellite channels

src/algorithms/observables/gnuradio_blocks/hybrid_observables_cc.cc

@@ -66,11 +66,6 @@ hybrid_observables_cc::hybrid_observables_cc(unsigned int nchannels, bool dump,
         {
             d_gnss_synchro_history_queue.push_back(std::deque<Gnss_Synchro>());
         }
-    // todo: this is a gnuradio scheduler hack.
-    // Migrate the queues to gnuradio set_history to see if the scheduler can handle
-    // the multiple output flow
-    d_max_noutputs = 100;
-    this->set_min_noutput_items(100);
 
     // ############# ENABLE DATA FILE LOG #################
     if (d_dump == true)
@@ -328,8 +323,15 @@ bool Hybrid_valueCompare_gnss_synchro_d_TOW(const Gnss_Synchro& a, double b)
     return (a.TOW_at_current_symbol_s) < (b);
 }
 
+void hybrid_observables_cc::forecast (int noutput_items __attribute__((unused)), gr_vector_int &ninput_items_required)
+{
+    for(unsigned int i = 0; i < d_nchannels; i++)
+        {
+            ninput_items_required[i] = 0; //set the required available samples in each call
+        }
+}
 
-int hybrid_observables_cc::general_work (int noutput_items __attribute__((unused)),
+int hybrid_observables_cc::general_work (int noutput_items ,
         gr_vector_int &ninput_items,
         gr_vector_const_void_star &input_items,
         gr_vector_void_star &output_items)
@@ -351,15 +353,27 @@ int hybrid_observables_cc::general_work (int noutput_items __attribute__((unused
      *  Multi-rate GNURADIO Block. Read how many input items are avaliable in each channel
      *  Record all synchronization data into queues
      */
+    bool zero_samples=true;
     for (unsigned int i = 0; i < d_nchannels; i++)
         {
             n_consume[i] = ninput_items[i];// full throttle
             for (int j = 0; j < n_consume[i]; j++)
                 {
                     d_gnss_synchro_history_queue[i].push_back(in[i][j]);
+                    zero_samples=false;
                 }
         }
 
+    //check if there are new channel data available
+    //This is required because the combination of several GNSS tracking signals
+    //leads to a multirrate inputs that can not warantee that every channel will have new data
+    //and forecast method is set to zero samples for each channel to avoid blockings
+    if (zero_samples==true)
+        {
+            usleep(500); // run this task at up to 2 kHz rate
+            return 0; // No new samples in this call, thus, return.
+        }
+
     bool channel_history_ok;
     do
         {
@@ -561,7 +575,7 @@ int hybrid_observables_cc::general_work (int noutput_items __attribute__((unused
                                 }
                         }
                 }
-        } while(channel_history_ok == true && d_max_noutputs > n_outputs);
+        } while(channel_history_ok == true && noutput_items > n_outputs);
 
     // Multi-rate consume!
     for (unsigned int i = 0; i < d_nchannels; i++)

src/algorithms/observables/gnuradio_blocks/hybrid_observables_cc.h

@@ -55,7 +55,7 @@ public:
     ~hybrid_observables_cc ();
     int general_work (int noutput_items, gr_vector_int &ninput_items,
             gr_vector_const_void_star &input_items, gr_vector_void_star &output_items);
-
+    void forecast (int noutput_items, gr_vector_int &ninput_items_required);
 private:
     friend hybrid_observables_cc_sptr
     hybrid_make_observables_cc(unsigned int nchannels, bool dump, std::string dump_filename, unsigned int deep_history);
@@ -66,7 +66,6 @@ private:
 
     double T_rx_s;
     double T_rx_step_s;
-    int d_max_noutputs;
     bool d_dump;
     unsigned int d_nchannels;
     unsigned int history_deep;

src/algorithms/tracking/gnuradio_blocks/galileo_e1_dll_pll_veml_tracking_cc.cc

@@ -953,7 +953,7 @@ int galileo_e1_dll_pll_veml_tracking_cc::general_work (int noutput_items __attri
 
     if (current_synchro_data.Flag_valid_symbol_output)
     {
-        return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+        return 1;
     }else{
         return 0;
     }

src/algorithms/tracking/gnuradio_blocks/galileo_e1_tcp_connector_tracking_cc.cc

@@ -513,7 +513,12 @@ int Galileo_E1_Tcp_Connector_Tracking_cc::general_work (int noutput_items __attr
     consume_each(d_current_prn_length_samples); // this is needed in gr::block derivates
     d_sample_counter += d_current_prn_length_samples; //count for the processed samples
 
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/galileo_e5a_dll_pll_tracking_cc.cc

@@ -733,7 +733,13 @@ int Galileo_E5a_Dll_Pll_Tracking_cc::general_work (int noutput_items __attribute
     d_secondary_delay = (d_secondary_delay + 1) % Galileo_E5a_Q_SECONDARY_CODE_LENGTH;
     d_sample_counter += d_current_prn_length_samples; //count for the processed samples
     consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+
+    if (current_synchro_data.Flag_valid_symbol_output)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_cc.cc

@@ -875,7 +875,12 @@ int gps_l1_ca_dll_pll_c_aid_tracking_cc::general_work (int noutput_items __attri
     consume_each(d_correlation_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_correlation_length_samples; //count for the processed samples
 
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_fpga_sc.cc

@@ -694,7 +694,12 @@ int gps_l1_ca_dll_pll_c_aid_tracking_fpga_sc::general_work(
     //consume_each(d_correlation_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_correlation_length_samples; //count for the processed samples
 
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_c_aid_tracking_sc.cc

@@ -879,7 +879,12 @@ int gps_l1_ca_dll_pll_c_aid_tracking_sc::general_work (int noutput_items __attri
     consume_each(d_correlation_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_correlation_length_samples; //count for the processed samples
 
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_tracking_cc.cc

@@ -736,7 +736,13 @@ int Gps_L1_Ca_Dll_Pll_Tracking_cc::general_work (int noutput_items __attribute__
 
     consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_current_prn_length_samples; // count for the processed samples
-    return 1; // output tracking result ALWAYS even in the case of d_enable_tracking==false
+
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_dll_pll_tracking_gpu_cc.cc

@@ -536,7 +536,12 @@ int Gps_L1_Ca_Dll_Pll_Tracking_GPU_cc::general_work (int noutput_items __attribu
     consume_each(d_correlation_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_correlation_length_samples; //count for the processed samples
 
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l1_ca_tcp_connector_tracking_cc.cc

@@ -549,7 +549,12 @@ int Gps_L1_Ca_Tcp_Connector_Tracking_cc::general_work (int noutput_items __attri
     d_sample_counter_seconds = d_sample_counter_seconds + ( static_cast<double>(d_current_prn_length_samples) / static_cast<double>(d_fs_in) );
     d_sample_counter += d_current_prn_length_samples; //count for the processed samples
 
-    return 1; //output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l2_m_dll_pll_tracking_cc.cc

@@ -729,7 +729,12 @@ int gps_l2_m_dll_pll_tracking_cc::general_work (int noutput_items __attribute__(
         }
     consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_current_prn_length_samples; // count for the processed samples
-    return 1; // output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }
 
 

src/algorithms/tracking/gnuradio_blocks/gps_l5i_dll_pll_tracking_cc.cc

@@ -729,7 +729,12 @@ int gps_l5i_dll_pll_tracking_cc::general_work (int noutput_items __attribute__((
         }
     consume_each(d_current_prn_length_samples); // this is necessary in gr::block derivates
     d_sample_counter += d_current_prn_length_samples; // count for the processed samples
-    return 1; // output tracking result ALWAYS even in the case of d_enable_tracking==false
+    if (d_enable_tracking)
+    {
+        return 1;
+    }else{
+        return 0;
+    }
 }