diff --git a/src/algorithms/PVT/gnuradio_blocks/rtklib_pvt_cc.cc b/src/algorithms/PVT/gnuradio_blocks/rtklib_pvt_cc.cc
index 1554884b0..4914bf020 100644
--- a/src/algorithms/PVT/gnuradio_blocks/rtklib_pvt_cc.cc
+++ b/src/algorithms/PVT/gnuradio_blocks/rtklib_pvt_cc.cc
@@ -1713,11 +1713,9 @@ int rtklib_pvt_cc::work (int noutput_items, gr_vector_const_void_star &input_ite
                     // DEBUG MESSAGE: Display position in console output
                     if( (d_ls_pvt->is_valid_position() == true) && (flag_display_pvt == true) )
                         {
-                            std::string text_green = "\033[32m";
-                            std::string text_reset = "\033[0m";
-                            std::cout << text_green << "Position at " << boost::posix_time::to_simple_string(d_ls_pvt->get_position_UTC_time())
+                            std::cout << TEXT_GREEN << "Position at " << boost::posix_time::to_simple_string(d_ls_pvt->get_position_UTC_time())
                                       << " UTC using " << d_ls_pvt->get_num_valid_observations() << " observations is Lat = " << d_ls_pvt->get_latitude() << " [deg], Long = " << d_ls_pvt->get_longitude()
-                                      << " [deg], Height= " << d_ls_pvt->get_height() << " [m]" << text_reset << std::endl;
+                                      << " [deg], Height= " << d_ls_pvt->get_height() << " [m]" << TEXT_RESET << std::endl;
 
                             LOG(INFO) << "Position at " << boost::posix_time::to_simple_string(d_ls_pvt->get_position_UTC_time())
                                       << " UTC using "<< d_ls_pvt->get_num_valid_observations() << " observations is Lat = " << d_ls_pvt->get_latitude() << " [deg], Long = " << d_ls_pvt->get_longitude()
diff --git a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_cc.cc b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_cc.cc
index 79810f000..f0766f528 100644
--- a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_cc.cc
+++ b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_cc.cc
@@ -350,11 +350,19 @@ int gps_l1_ca_telemetry_decoder_cc::general_work (int noutput_items __attribute_
             //double decoder_latency_ms=(double)(current_symbol.Tracking_sample_counter-d_symbol_history.at(0).Tracking_sample_counter)
             //        /(double)current_symbol.fs;
             // update TOW at the preamble instant (account with decoder latency)
-            d_TOW_at_Preamble = d_GPS_FSM.d_nav.d_TOW + 2 * GPS_L1_CA_CODE_PERIOD + GPS_CA_PREAMBLE_DURATION_S;
+            double tmp_tow = d_TOW_at_current_symbol + GPS_L1_CA_CODE_PERIOD;
 
+            d_TOW_at_Preamble = d_GPS_FSM.d_nav.d_TOW + 2 * GPS_L1_CA_CODE_PERIOD + GPS_CA_PREAMBLE_DURATION_S;
             d_TOW_at_current_symbol = floor(d_TOW_at_Preamble * 1000.0) / 1000.0;
             flag_TOW_set = true;
             d_flag_new_tow_available = false;
+            double tmp_diff = std::fabs(tmp_tow - d_TOW_at_current_symbol);
+            if ((tmp_tow != 0) or (tmp_diff > 0.0))
+            {
+                std::cout << TEXT_RED <<
+                        "GPS L1 C/A. TOW incoherence on channel: "<< d_channel << ". TOW difference = " <<
+                        tmp_diff * 1000.0 << " [ms]" << TEXT_RESET << std::endl;
+            }
         }
     else
         {
diff --git a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2c_telemetry_decoder_cc.cc b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2c_telemetry_decoder_cc.cc
index 20be2dcf9..be426b70a 100644
--- a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2c_telemetry_decoder_cc.cc
+++ b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2c_telemetry_decoder_cc.cc
@@ -156,17 +156,15 @@ int gps_l2c_telemetry_decoder_cc::general_work (int noutput_items __attribute__(
             //* delay by the formulae:
             //* \code
             //* symbolTime_ms = msg->tow * 6000 + *pdelay * 20 + (12 * 20); 12 symbols of the encoder's transitory
-            double tmp_tow= d_TOW_at_current_symbol += GPS_L2_M_PERIOD;
+            double tmp_tow = d_TOW_at_current_symbol + GPS_L2_M_PERIOD;
             d_TOW_at_current_symbol = static_cast<double>(msg.tow) * 6.0 + static_cast<double>(delay) * GPS_L2_M_PERIOD + 12 * GPS_L2_M_PERIOD;
             d_TOW_at_current_symbol = floor(d_TOW_at_current_symbol * 1000.0) / 1000.0;
-            double tmp_diff = std::fabs(tmp_tow-d_TOW_at_current_symbol);
+            double tmp_diff = std::fabs(tmp_tow - d_TOW_at_current_symbol);
             if ((tmp_tow != 0) or (tmp_diff > 0.0))
             {
-                std::string text_red = "\033[31m";
-                std::string text_reset = "\033[0m";
-                std::cout << text_red <<
+                std::cout << TEXT_RED <<
                         "GPS L2C. TOW incoherence on channel: "<< d_channel << ". TOW difference = " <<
-                        tmp_diff * 1000.0 << " [ms]" << text_reset << std::endl;
+                        tmp_diff * 1000.0 << " [ms]" << TEXT_RESET << std::endl;
             }
             d_flag_valid_word = true;
         }
diff --git a/src/core/system_parameters/MATH_CONSTANTS.h b/src/core/system_parameters/MATH_CONSTANTS.h
index 8c8dfbbe5..2a5f376e6 100644
--- a/src/core/system_parameters/MATH_CONSTANTS.h
+++ b/src/core/system_parameters/MATH_CONSTANTS.h
@@ -31,6 +31,8 @@
 #ifndef GNSS_SDR_MATH_CONSTANTS_H_
 #define GNSS_SDR_MATH_CONSTANTS_H_
 
+#include<string>
+
 /* Constants for scaling the ephemeris found in the data message
         the format is the following: TWO_N5 -> 2^-5, TWO_P4 -> 2^4, PI_TWO_N43 -> Pi*2^-43, etc etc
         Additionally some of the PI*2^N terms are used in the tracking stuff
@@ -41,6 +43,11 @@
         ONE_PI_TWO_PX = (1/Pi)*2^X
 */
 
+const std::string TEXT_RED   = "\033[31m";
+const std::string TEXT_GREEN = "\033[32m";
+const std::string TEXT_RESET = "\033[0m";
+
+
 const double PI = 3.1415926535897932;             //!<  pi
 const double PI_2 = 2.0 * PI;                     //!<  2 * pi