diff --git a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
index bd72d4cde..ed358e9b5 100644
--- a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
+++ b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
@@ -153,6 +153,19 @@ gps_l1_ca_telemetry_decoder_gs::~gps_l1_ca_telemetry_decoder_gs()
 {
     DLOG(INFO) << "GPS L1 C/A Telemetry decoder block (channel " << d_channel << ") destructor called.";
     size_t pos = 0;
+
+    if( subframe_data_file.is_open())
+    {
+         try
+                {
+                    subframe_data_file.close();
+                }
+            catch (const std::exception &ex)
+                {
+                    LOG(WARNING) << "*** Exception in destructor closing the subframe file " << ex.what();
+                }
+    }
+
     if (d_dump_file.is_open() == true)
         {
             pos = d_dump_file.tellp();
@@ -228,6 +241,20 @@ void gps_l1_ca_telemetry_decoder_gs::set_channel(int32_t channel)
     d_nav.set_channel(channel);
     DLOG(INFO) << "Navigation channel set to " << channel;
     // ############# ENABLE DATA FILE LOG #################
+    if( subframe_data_file.is_open()==false)
+    {       
+        try
+        {
+            std::string file_name = subframe_file_prefix+std::to_string(channel)+std::string(".csv");
+            subframe_data_file.open(file_name.data());
+        }
+        catch(const std::ofstream::failure &e)
+        {
+            std::cerr << "*** Fail to open subframe file for channel "+ channel << "\n"
+            << e.what() << "\n";
+        }        
+    }
+
     if (d_dump == true)
         {
             if (d_dump_file.is_open() == false)
@@ -349,7 +376,7 @@ bool gps_l1_ca_telemetry_decoder_gs::decode_subframe(double cn0, bool flag_inver
                         }
                     d_nav_msg_packet.nav_message = subframe_bits.to_string();
                 }
-            const int32_t subframe_ID = d_nav.subframe_decoder(subframe.data());  // decode the subframe
+            const int32_t subframe_ID = d_nav.subframe_decoder(subframe.data(),&subframe_data_file);  // decode the subframe
             if (subframe_ID > 0 && subframe_ID < 6)
                 {
                     switch (subframe_ID)
diff --git a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.h b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.h
index 5939163bc..9a6d99143 100644
--- a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.h
+++ b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.h
@@ -89,6 +89,9 @@ private:
     std::string d_dump_filename;
     std::ofstream d_dump_file;
 
+    std::ofstream subframe_data_file;
+    std::string subframe_file_prefix = "/mnt/c/Documents and Settings/Admin/gnss-sdr/data_treatment/subframes/subframe_";
+
     boost::circular_buffer<float> d_symbol_history;
 
     uint64_t d_sample_counter;
diff --git a/src/core/system_parameters/gps_navigation_message.cc b/src/core/system_parameters/gps_navigation_message.cc
index b17458da7..fc65aaadb 100644
--- a/src/core/system_parameters/gps_navigation_message.cc
+++ b/src/core/system_parameters/gps_navigation_message.cc
@@ -24,6 +24,8 @@
 #include <iostream>  // for operator<<, cout
 #include <limits>    // for std::numeric_limits
 
+#include <fstream>
+
 
 Gps_Navigation_Message::Gps_Navigation_Message()
 {
@@ -78,7 +80,7 @@ int64_t Gps_Navigation_Message::read_navigation_signed(const std::bitset<GPS_SUB
 }
 
 
-int32_t Gps_Navigation_Message::subframe_decoder(const char* subframe)
+int32_t Gps_Navigation_Message::subframe_decoder(const char* subframe, std::ofstream* subframe_writer)
 {
     uint32_t gps_word;
 
@@ -97,6 +99,12 @@ int32_t Gps_Navigation_Message::subframe_decoder(const char* subframe)
 
     const auto subframe_ID = static_cast<int32_t>(read_navigation_unsigned(subframe_bits, SUBFRAME_ID));
 
+    if(subframe_writer!=nullptr)
+    {        
+        *subframe_writer << "*" << subframe_ID << "*";
+        *subframe_writer << subframe_bits << "\n"; 
+    }    
+
     // Decode all 5 sub-frames
     switch (subframe_ID)
         {
diff --git a/src/core/system_parameters/gps_navigation_message.h b/src/core/system_parameters/gps_navigation_message.h
index 16e8b2a9f..d378b912d 100644
--- a/src/core/system_parameters/gps_navigation_message.h
+++ b/src/core/system_parameters/gps_navigation_message.h
@@ -68,7 +68,7 @@ public:
     /*!
      * \brief Decodes the GPS NAV message
      */
-    int32_t subframe_decoder(const char* subframe);
+    int32_t subframe_decoder(const char* subframe, std::ofstream*  subframe_writer=nullptr);
 
     /*!
      * \brief Computes the Coordinated Universal Time (UTC) and