diff --git a/src/core/libs/osnma_msg_receiver.cc b/src/core/libs/osnma_msg_receiver.cc
index 1f96afb61..1131ffbc3 100644
--- a/src/core/libs/osnma_msg_receiver.cc
+++ b/src/core/libs/osnma_msg_receiver.cc
@@ -127,9 +127,11 @@ void osnma_msg_receiver::msg_handler_osnma(const pmt::pmt_t& msg)
 
                     // compare local time with OSNMA subframe time
                     d_GST_SIS = nma_msg->TOW_sf0 + nma_msg->WN_sf0 * 604800; // TODO - unsure about this operation and of the -24 seconds,...
-                    auto utc = galileo_utc_model.GST_to_UTC_time(d_GST_SIS, static_cast<int>(nma_msg->WN_sf0));
-                    double_t T_L = 15; // TODO - to define the maximum allowed time difference between local time and OSNMA subframe time
-                    if(abs(d_GST_SIS - d_receiver_time) <= T_L)
+                    // instantiate galileo_utc_model and call init function, then call GST_to_UTC_time
+                    Galileo_Utc_Model::init(nma_msg->utc_data);
+                    double_t utc = Galileo_Utc_Model::GST_to_UTC_time(static_cast<double>(d_GST_SIS), static_cast<int>(nma_msg->WN_sf0));
+                    double_t T_L = 15.0; // TODO - to define the maximum allowed time difference between local time and OSNMA subframe time
+                    if(abs(utc - d_receiver_time) <= T_L)
                         {
                             process_osnma_message(nma_msg);
                         }
diff --git a/src/core/libs/osnma_msg_receiver.h b/src/core/libs/osnma_msg_receiver.h
index 27c07ae56..efaadd6a2 100644
--- a/src/core/libs/osnma_msg_receiver.h
+++ b/src/core/libs/osnma_msg_receiver.h
@@ -72,6 +72,7 @@ private:
     void read_mack_body();
     void process_mack_message(const std::shared_ptr<OSNMA_msg>& osnma_msg);
 
+//    Galileo_Utc_Model galileo_utc_model;
     boost::circular_buffer<MACK_message> d_old_mack_message;
     boost::circular_buffer<NavData> d_old_navdata_buffer; // buffer that holds last 10 received navdata messages
     std::unique_ptr<OSNMA_DSM_Reader> d_dsm_reader;
@@ -91,7 +92,7 @@ private:
     uint8_t d_Lt_min {}; // minimum equivalent tag length
     uint32_t d_GST_0 {};
     uint32_t d_GST_SIS {};
-    std::time_t d_receiver_time {};
+    std::time_t d_receiver_time {}; // PVT time computed by the local receiver
 };
 
 
diff --git a/src/core/system_parameters/galileo_utc_model.cc b/src/core/system_parameters/galileo_utc_model.cc
index d14aa8c42..74ea2ba43 100644
--- a/src/core/system_parameters/galileo_utc_model.cc
+++ b/src/core/system_parameters/galileo_utc_model.cc
@@ -17,8 +17,19 @@
 #include "galileo_utc_model.h"
 #include <cmath>
 
+void Galileo_Utc_Model::init(const Galileo_Utc_Model& data)
+{
+    A0 = data.A0;
+    A1 = data.A1;
+    Delta_tLS = data.Delta_tLS;
+    Delta_tLSF = data.Delta_tLSF;
+    DN = data.DN;
+    tot = data.tot;
+    WNot = data.WNot;
+    WN_LSF = data.WN_LSF;
 
-double Galileo_Utc_Model::GST_to_UTC_time(double t_e, int32_t WN) const
+}
+double Galileo_Utc_Model::GST_to_UTC_time(double t_e, int32_t WN)
 {
     double t_Utc;
     double t_Utc_daytime;
@@ -76,4 +87,5 @@ double Galileo_Utc_Model::GST_to_UTC_time(double t_e, int32_t WN) const
 double Galileo_Utc_Model::UTC_time_to_GST(double t_Utc, int32_t WN) const
 {
     // TODO
+    return 0;
 }
\ No newline at end of file
diff --git a/src/core/system_parameters/galileo_utc_model.h b/src/core/system_parameters/galileo_utc_model.h
index 6024a41d0..c762c428f 100644
--- a/src/core/system_parameters/galileo_utc_model.h
+++ b/src/core/system_parameters/galileo_utc_model.h
@@ -41,19 +41,29 @@ public:
      */
     Galileo_Utc_Model() = default;
 
+    /**
+     * @brief Initialize the Galileo_UTC_Model with the provided data.
+     *
+     * This function initializes the Galileo_UTC_Model object with the given data.
+     *
+     * @param data The Galileo_UTC_Model object containing the data.
+     */
+    static void init(const Galileo_Utc_Model& data);
+
     // double TOW;
-    double GST_to_UTC_time(double t_e, int32_t WN) const;  //!< GST-UTC Conversion Algorithm and Parameters
+    static double GST_to_UTC_time(double t_e, int32_t WN);  //!< GST-UTC Conversion Algorithm and Parameters
     double UTC_time_to_GST(double t_Utc, int32_t WN) const;
 
+    // TODO - make them private?
     // Word type 6: GST-UTC conversion parameters
-    double A0{};
-    double A1{};
-    int32_t Delta_tLS{};
-    int32_t tot{};   //!< UTC data reference Time of Week [s]
-    int32_t WNot{};  //!< UTC data reference Week number [week]
-    int32_t WN_LSF{};
-    int32_t DN{};
-    int32_t Delta_tLSF{};
+    static double A0;
+    static double A1;
+    static int32_t Delta_tLS;
+    static int32_t tot;   //!< UTC data reference Time of Week [s]
+    static int32_t WNot;  //!< UTC data reference Week number [week]
+    static int32_t WN_LSF;
+    static int32_t DN;
+    static int32_t Delta_tLSF;
 
     // GPS to Galileo GST conversion parameters
     double A_0G{};