Implement reading of reduced CED data in Galileo E1B INAV message. Used if found

docs/changelog.md

@@ -10,20 +10,13 @@ SPDX-FileCopyrightText: 2011-2021 Carles Fernandez-Prades <carles.fernandez@cttc
 
 ## [Unreleased](https://github.com/gnss-sdr/gnss-sdr/tree/next)
 
-### Improvements in Portability:
+### Improvements in Availability:
 
-- Avoid collision of the `cpu_features` library when installing the
+- Added the reading of reduced clock and ephemeris data (CED) in the Galileo E1B
-  `volk_gnsssdr` library by its own, and VOLK has already installed its version.
+  INAV message introduced in Galileo ICD v2.0. If the reduced CED is available
-  Added a new building option `ENABLE_OWN_CPUFEATURES`, defaulting to `ON` when
+  before the full ephemeris set, it is used for PVT computation until the full
-  building `gnss-sdr` but defaulting to `OFF` when building a stand-alone
+  set has not yet been received. This can contribute to shorten the
-  version of `volk_gnsssdr`. When this building option is set to `ON`, it forces
+  Time-To-First-Fix.
-  the building of the local version of the cpu_features library, regardless of
-  whether it is already installed or not.
-- Fix building when using the Xcode generator, Xcode >= 12 and CMake >= 3.19.
-- Fix building of FPGA blocks when linking against GNU Radio >= 3.9 and/or
-  Boost >= 1.74.
-- Fix linking of the `<filesystem>` library when using GCC 8.x and GNU Radio >=
-  3.8.
 
 ### Improvements in Maintainability:
 
@@ -46,6 +39,21 @@ SPDX-FileCopyrightText: 2011-2021 Carles Fernandez-Prades <carles.fernandez@cttc
   providing a common nomenclature for ephemeris' parameters. New generated XML
   files make use of the new parameters' name.
 
+### Improvements in Portability:
+
+- Avoid collision of the `cpu_features` library when installing the
+  `volk_gnsssdr` library by its own, and VOLK has already installed its version.
+  Added a new building option `ENABLE_OWN_CPUFEATURES`, defaulting to `ON` when
+  building `gnss-sdr` but defaulting to `OFF` when building a stand-alone
+  version of `volk_gnsssdr`. When this building option is set to `ON`, it forces
+  the building of the local version of the cpu_features library, regardless of
+  whether it is already installed or not.
+- Fix building when using the Xcode generator, Xcode >= 12 and CMake >= 3.19.
+- Fix building of FPGA blocks when linking against GNU Radio >= 3.9 and/or
+  Boost >= 1.74.
+- Fix linking of the `<filesystem>` library when using GCC 8.x and GNU Radio >=
+  3.8.
+
 ### Improvements in Usability:
 
 - Avoid segmentation faults in the flow graph connection and/or starting due to

src/algorithms/telemetry_decoder/gnuradio_blocks/galileo_telemetry_decoder_gs.cc

@@ -208,6 +208,9 @@ galileo_telemetry_decoder_gs::galileo_telemetry_decoder_gs(
     d_state0.reserve(max_states);
     d_state1.reserve(max_states);
 
+    d_inav_nav.init_PRN(d_satellite.get_PRN());
+    d_first_eph_sent = false;
+
     // create appropriate transition matrices
     nsc_transit(d_out0.data(), d_state0.data(), 0, g_encoder.data(), d_KK, d_nn);
     nsc_transit(d_out1.data(), d_state1.data(), 1, g_encoder.data(), d_KK, d_nn);
@@ -354,7 +357,19 @@ void galileo_telemetry_decoder_gs::decode_INAV_word(float *page_part_symbols, in
                     std::cout << TEXT_BLUE << "New Galileo E5b I/NAV message received in channel " << d_channel << ": ephemeris from satellite " << d_satellite << TEXT_RESET << '\n';
                 }
             this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
+            d_first_eph_sent = true;  // do not send reduced CED anymore, since we have the full ephemeris set
         }
+    else
+        {
+            // If we still do not have ephemeris, check if we have a reduced CED
+            if ((d_band == '1') && !d_first_eph_sent && (d_inav_nav.have_new_reduced_ced() == true))
+                {
+                    const std::shared_ptr<Galileo_Ephemeris> tmp_obj = std::make_shared<Galileo_Ephemeris>(d_inav_nav.get_reduced_ced());
+                    std::cout << "New Galileo E1 I/NAV reduced CED message received in channel " << d_channel << " from satellite " << d_satellite << '\n';
+                    this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
+                }
+        }
+
     if (d_inav_nav.have_new_iono_and_GST() == true)
         {
             // get object for this SV (mandatory)

src/algorithms/telemetry_decoder/gnuradio_blocks/galileo_telemetry_decoder_gs.h

@@ -139,6 +139,7 @@ private:
     bool d_dump;
     bool d_dump_mat;
     bool d_remove_dat;
+    bool d_first_eph_sent;
 };
 
 

src/core/system_parameters/CMakeLists.txt

@@ -17,6 +17,7 @@ set(SYSTEM_PARAMETERS_SOURCES
     galileo_cnav_message.cc
     galileo_fnav_message.cc
     galileo_inav_message.cc
+    galileo_reduced_ced.cc
     beidou_dnav_navigation_message.cc
     beidou_dnav_ephemeris.cc
     sbas_ephemeris.cc
@@ -52,6 +53,7 @@ set(SYSTEM_PARAMETERS_HEADERS
     galileo_fnav_message.h
     galileo_has_data.h
     galileo_inav_message.h
+    galileo_reduced_ced.h
     sbas_ephemeris.h
     gps_cnav_ephemeris.h
     gps_cnav_navigation_message.h

src/core/system_parameters/Galileo_INAV.h

@@ -245,12 +245,44 @@ const std::vector<std::pair<int32_t, int32_t>> T_0_G_10_BIT({{115, 8}});
 constexpr int32_t T_0_G_10_LSB = 3600;
 const std::vector<std::pair<int32_t, int32_t>> WN_0_G_10_BIT({{123, 6}});
 
+/* Page 16 */
+constexpr double CED_DeltaAred_LSB = TWO_P8;
+const std::vector<std::pair<int32_t, int32_t>> CED_DeltaAred_BIT({{7, 5}});
+constexpr double CED_exred_LSB = TWO_N22;
+const std::vector<std::pair<int32_t, int32_t>> CED_exred_BIT({{12, 13}});
+constexpr double CED_eyred_LSB = TWO_N22;
+const std::vector<std::pair<int32_t, int32_t>> CED_eyred_BIT({{25, 13}});
+constexpr double CED_Deltai0red_LSB = TWO_N22;
+const std::vector<std::pair<int32_t, int32_t>> CED_Deltai0red_BIT({{38, 17}});
+constexpr double CED_Omega0red_LSB = TWO_N22;
+const std::vector<std::pair<int32_t, int32_t>> CED_Omega0red_BIT({{55, 23}});
+constexpr double CED_lambda0red_LSB = TWO_N22;
+const std::vector<std::pair<int32_t, int32_t>> CED_lambda0red_BIT({{78, 23}});
+constexpr double CED_af0red_LSB = TWO_N26;
+const std::vector<std::pair<int32_t, int32_t>> CED_af0red_BIT({{101, 22}});
+constexpr double CED_af1red_LSB = TWO_N35;
+const std::vector<std::pair<int32_t, int32_t>> CED_af1red_BIT({{123, 6}});
+
+/* Pages 17, 18, 19, 20 */
+const std::vector<std::pair<int32_t, int32_t>> RS_IODNAV_LSBS({{15, 2}});
+constexpr size_t INAV_RS_SUBVECTOR_LENGTH = 15;
+constexpr size_t INAV_RS_PARITY_VECTOR_LENGTH = 60;
+constexpr int32_t BITS_IN_OCTET = 8;
+constexpr int32_t FIRST_RS_BIT = 7;
+constexpr int32_t FIRST_RS_BIT_AFTER_IODNAV = 17;
 
 /* Page 0 */
 const std::vector<std::pair<int32_t, int32_t>> TIME_0_BIT({{7, 2}});
 const std::vector<std::pair<int32_t, int32_t>> WN_0_BIT({{97, 12}});
 const std::vector<std::pair<int32_t, int32_t>> TOW_0_BIT({{109, 20}});
 
+/* Secondary Synchronization Patters */
+constexpr char GALILEO_INAV_PLAIN_SSP1[9] = "00000100";
+constexpr char GALILEO_INAV_PLAIN_SSP2[9] = "00101011";
+constexpr char GALILEO_INAV_PLAIN_SSP3[9] = "00101111";
+constexpr char GALILEO_INAV_ENCODED_SSP1[17] = "1110100100100101";
+constexpr char GALILEO_INAV_ENCODED_SSP2[17] = "0110110001001110";
+constexpr char GALILEO_INAV_ENCODED_SSP3[17] = "1101000000111110";
 
 /** \} */
 /** \} */

src/core/system_parameters/MATH_CONSTANTS.h

@@ -58,6 +58,7 @@ constexpr double TWO_PI = 2.0 * GNSS_PI;     //!< 2 * pi
 
 constexpr double TWO_P3 = 8.0;                      //!< 2^3
 constexpr double TWO_P4 = 16.0;                     //!< 2^4
+constexpr double TWO_P8 = 256.0;                    //!< 2^8
 constexpr double TWO_P11 = 2048.0;                  //!< 2^11
 constexpr double TWO_P12 = 4096.0;                  //!< 2^12
 constexpr double TWO_P14 = 16384.0;                 //!< 2^14
@@ -83,9 +84,11 @@ constexpr double TWO_N18 = 3.814697265625000e-006;  //!< 2^-18
 constexpr double TWO_N19 = 1.907348632812500e-006;  //!< 2^-19
 constexpr double TWO_N20 = 9.536743164062500e-007;  //!< 2^-20
 constexpr double TWO_N21 = 4.768371582031250e-007;  //!< 2^-21
+constexpr double TWO_N22 = 2.384185791015625e-007;  //!< 2^-22
 constexpr double TWO_N23 = 1.192092895507810e-007;  //!< 2^-23
 constexpr double TWO_N24 = 5.960464477539063e-008;  //!< 2^-24
 constexpr double TWO_N25 = 2.980232238769531e-008;  //!< 2^-25
+constexpr double TWO_N26 = 1.490116119384765e-009;  //!< 2^-26
 constexpr double TWO_N27 = 7.450580596923828e-009;  //!< 2^-27
 constexpr double TWO_N29 = 1.862645149230957e-009;  //!< 2^-29
 constexpr double TWO_N30 = 9.313225746154785e-010;  //!< 2^-30

src/core/system_parameters/galileo_inav_message.cc

@@ -17,6 +17,7 @@
  */
 
 #include "galileo_inav_message.h"
+#include "galileo_reduced_ced.h"
 #include <boost/crc.hpp>             // for boost::crc_basic, boost::crc_optimal
 #include <boost/dynamic_bitset.hpp>  // for boost::dynamic_bitset
 #include <glog/logging.h>            // for DLOG
@@ -262,6 +263,18 @@ bool Galileo_Inav_Message::have_new_almanac()  // Check if we have a new almanac
 }
 
 
+bool Galileo_Inav_Message::have_new_reduced_ced()
+{
+    // Check if we have a new CED data set stored in the galileo navigation class
+    if ((flag_CED == true) && (WN_5 > 0))  // We need the week number to compute GST
+        {
+            flag_CED = false;
+            return true;
+        }
+    return false;
+}
+
+
 Galileo_Ephemeris Galileo_Inav_Message::get_ephemeris() const
 {
     Galileo_Ephemeris ephemeris;
@@ -416,6 +429,42 @@ Galileo_Almanac_Helper Galileo_Inav_Message::get_almanac() const
 }
 
 
+Galileo_Ephemeris Galileo_Inav_Message::get_reduced_ced() const
+{
+    Galileo_Reduced_CED ced{};
+    ced.PRN = SV_ID_PRN_4;
+    if (TOW_5 > TOW_6)
+        {
+            ced.TOTRedCED = WN_5 * 604800 + TOW_5 + 4;  // According to ICD 2.0, Table 38
+        }
+    else
+        {
+            ced.TOTRedCED = WN_5 * 604800 + TOW_6 + 10;  // According to ICD 2.0, Table 38
+        }
+    std::array<int32_t, 4> iod_navs = {IOD_nav_1, IOD_nav_2, IOD_nav_3, IOD_nav_4};
+    int32_t max_IOD_nav = IOD_nav_1;
+    for (int i = 1; i < 4; i++)
+        {
+            if (iod_navs[i] > max_IOD_nav)
+                {
+                    max_IOD_nav = iod_navs[i];
+                }
+        }
+    ced.IODnav = max_IOD_nav;
+    ced.DeltaAred = ced_DeltaAred;
+    ced.exred = ced_exred;
+    ced.eyred = ced_eyred;
+    ced.Deltai0red = ced_Deltai0red;
+    ced.Omega0red = ced_Omega0red;
+    ced.lambda0red = ced_lambda0red;
+    ced.af0red = ced_af0red;
+    ced.af1red = ced_af1red;
+
+    Galileo_Ephemeris eph = ced.compute_eph();
+    return eph;
+}
+
+
 int32_t Galileo_Inav_Message::page_jk_decoder(const char* data_jk)
 {
     const std::string data_jk_string = data_jk;
@@ -750,6 +799,99 @@ int32_t Galileo_Inav_Message::page_jk_decoder(const char* data_jk)
             DLOG(INFO) << "flag_tow_set" << flag_TOW_set;
             break;
 
+        case 16:  // Word type 16: Reduced Clock and Ephemeris Data (CED) parameters
+            DLOG(INFO) << "Word type 16 arrived";
+            ced_DeltaAred = static_cast<double>(read_navigation_signed(data_jk_bits, CED_DeltaAred_BIT));
+            ced_DeltaAred = ced_DeltaAred * CED_DeltaAred_LSB;
+            DLOG(INFO) << "DeltaAred = " << ced_DeltaAred;
+            ced_exred = static_cast<double>(read_navigation_signed(data_jk_bits, CED_exred_BIT));
+            ced_exred = ced_exred * CED_exred_LSB;
+            DLOG(INFO) << "exred = " << ced_exred;
+            ced_eyred = static_cast<double>(read_navigation_signed(data_jk_bits, CED_eyred_BIT));
+            ced_eyred = ced_eyred * CED_eyred_LSB;
+            DLOG(INFO) << "eyred = " << ced_eyred;
+            ced_Deltai0red = static_cast<double>(read_navigation_signed(data_jk_bits, CED_Deltai0red_BIT));
+            ced_Deltai0red = ced_Deltai0red * CED_Deltai0red_LSB;
+            DLOG(INFO) << "Deltai0red = " << ced_Deltai0red;
+            ced_Omega0red = static_cast<double>(read_navigation_signed(data_jk_bits, CED_Omega0red_BIT));
+            ced_Omega0red = ced_Omega0red * CED_Omega0red_LSB;
+            DLOG(INFO) << "Omega0red = " << ced_Omega0red;
+            ced_lambda0red = static_cast<double>(read_navigation_signed(data_jk_bits, CED_lambda0red_BIT));
+            ced_lambda0red = ced_lambda0red * CED_lambda0red_LSB;
+            DLOG(INFO) << "lambda0red = " << ced_lambda0red;
+            ced_af0red = static_cast<double>(read_navigation_signed(data_jk_bits, CED_af0red_BIT));
+            ced_af0red = ced_af0red * CED_af0red_LSB;
+            DLOG(INFO) << "af0red = " << ced_af0red;
+            ced_af1red = static_cast<double>(read_navigation_signed(data_jk_bits, CED_af1red_BIT));
+            ced_af1red = ced_af1red * CED_af1red_LSB;
+            DLOG(INFO) << "af1red = " << ced_af1red;
+            flag_CED = true;
+            break;
+
+        case 17:  // Word type 17: FEC2 Reed-Solomon for CED
+            {
+                std::vector<std::pair<int32_t, int32_t>> gamma_octet_bits({{FIRST_RS_BIT, BITS_IN_OCTET}});
+                gamma_rs0[0] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                IODnav_LSB17 = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, RS_IODNAV_LSBS));
+                DLOG(INFO) << "IODnav 2 LSBs in Word type 17: " << static_cast<float>(IODnav_LSB17);
+                int32_t start_bit = FIRST_RS_BIT_AFTER_IODNAV;
+                for (size_t i = 1; i < INAV_RS_SUBVECTOR_LENGTH; i++)
+                    {
+                        gamma_octet_bits[0] = std::pair<int32_t, int32_t>({start_bit, BITS_IN_OCTET});
+                        gamma_rs0[i] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                        start_bit += BITS_IN_OCTET;
+                    }
+                break;
+            }
+
+        case 18:  // Word type 18: FEC2 Reed-Solomon for CED
+            {
+                std::vector<std::pair<int32_t, int32_t>> gamma_octet_bits({{FIRST_RS_BIT, BITS_IN_OCTET}});
+                gamma_rs1[0] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                IODnav_LSB18 = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, RS_IODNAV_LSBS));
+                DLOG(INFO) << "IODnav 2 LSBs in Word type 18: " << static_cast<float>(IODnav_LSB18);
+                int32_t start_bit = FIRST_RS_BIT_AFTER_IODNAV;
+                for (size_t i = 1; i < INAV_RS_SUBVECTOR_LENGTH; i++)
+                    {
+                        gamma_octet_bits[0] = std::pair<int32_t, int32_t>({start_bit, BITS_IN_OCTET});
+                        gamma_rs1[i] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                        start_bit += BITS_IN_OCTET;
+                    }
+                break;
+            }
+
+        case 19:  // Word type 19: FEC2 Reed-Solomon for CED
+            {
+                std::vector<std::pair<int32_t, int32_t>> gamma_octet_bits({{FIRST_RS_BIT, BITS_IN_OCTET}});
+                gamma_rs2[0] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                IODnav_LSB19 = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, RS_IODNAV_LSBS));
+                DLOG(INFO) << "IODnav 2 LSBs in Word type 19: " << static_cast<float>(IODnav_LSB19);
+                int32_t start_bit = FIRST_RS_BIT_AFTER_IODNAV;
+                for (size_t i = 1; i < INAV_RS_SUBVECTOR_LENGTH; i++)
+                    {
+                        gamma_octet_bits[0] = std::pair<int32_t, int32_t>({start_bit, BITS_IN_OCTET});
+                        gamma_rs2[i] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                        start_bit += BITS_IN_OCTET;
+                    }
+                break;
+            }
+
+        case 20:  // Word type 20: FEC2 Reed-Solomon for CED
+            {
+                std::vector<std::pair<int32_t, int32_t>> gamma_octet_bits({{FIRST_RS_BIT, BITS_IN_OCTET}});
+                gamma_rs3[0] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                IODnav_LSB20 = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, RS_IODNAV_LSBS));
+                DLOG(INFO) << "IODnav 2 LSBs in Word type 20: " << static_cast<float>(IODnav_LSB20);
+                int32_t start_bit = FIRST_RS_BIT_AFTER_IODNAV;
+                for (size_t i = 1; i < INAV_RS_SUBVECTOR_LENGTH; i++)
+                    {
+                        gamma_octet_bits[0] = std::pair<int32_t, int32_t>({start_bit, BITS_IN_OCTET});
+                        gamma_rs3[i] = static_cast<uint8_t>(read_navigation_unsigned(data_jk_bits, gamma_octet_bits));
+                        start_bit += BITS_IN_OCTET;
+                    }
+                break;
+            }
+
         case 0:  // Word type 0: I/NAV Spare Word
             Time_0 = static_cast<int32_t>(read_navigation_unsigned(data_jk_bits, TIME_0_BIT));
             DLOG(INFO) << "Time_0= " << Time_0;

src/core/system_parameters/galileo_inav_message.h

@@ -78,6 +78,11 @@ public:
      */
     bool have_new_almanac();
 
+    /*
+     * \brief Returns true if new Reduced CED parameters have arrived. The flag is set to false when the function is executed
+     */
+    bool have_new_reduced_ced();
+
     /*
      * \brief Returns a Galileo_Ephemeris object filled with the latest navigation data received
      */
@@ -98,6 +103,11 @@ public:
      */
     Galileo_Almanac_Helper get_almanac() const;
 
+    /*
+     * \brief Returns a Galileo_Ephemeris object filled with the latest reduced CED received
+     */
+    Galileo_Ephemeris get_reduced_ced() const;
+
     inline bool get_flag_CRC_test() const
     {
         return flag_CRC_test;
@@ -173,6 +183,14 @@ public:
         return WN_0G_10;
     }
 
+    /*
+     * \brief Initialize PRN field so we do not need to wait for page 4.
+     */
+    inline void init_PRN(uint32_t prn)
+    {
+        SV_ID_PRN_4 = prn;
+    }
+
 private:
     bool CRC_test(std::bitset<GALILEO_DATA_FRAME_BITS> bits, uint32_t checksum) const;
     bool read_navigation_bool(std::bitset<GALILEO_DATA_JK_BITS> bits, const std::vector<std::pair<int32_t, int32_t>>& parameter) const;
@@ -321,6 +339,27 @@ private:
     int32_t WN_0{};
     int32_t TOW_0{};
 
+    // Word type 16: Reduced Clock and Ephemeris Data (CED) parameters
+    double ced_DeltaAred{};
+    double ced_exred{};
+    double ced_eyred{};
+    double ced_Deltai0red{};
+    double ced_Omega0red{};
+    double ced_lambda0red{};
+    double ced_af0red{};
+    double ced_af1red{};
+
+    // Word types 17, 18, 19, 20: Reed-Solomon parity vector
+    std::vector<uint8_t> gamma_rs0{INAV_RS_SUBVECTOR_LENGTH, 0};
+    std::vector<uint8_t> gamma_rs1{INAV_RS_SUBVECTOR_LENGTH, 0};
+    std::vector<uint8_t> gamma_rs2{INAV_RS_SUBVECTOR_LENGTH, 0};
+    std::vector<uint8_t> gamma_rs3{INAV_RS_SUBVECTOR_LENGTH, 0};
+    std::vector<uint8_t> rs_parity_vector{INAV_RS_PARITY_VECTOR_LENGTH, 0};
+    uint8_t IODnav_LSB17{};
+    uint8_t IODnav_LSB18{};
+    uint8_t IODnav_LSB19{};
+    uint8_t IODnav_LSB20{};
+
     double Galileo_satClkDrift{};
 
     bool flag_CRC_test{};
@@ -346,6 +385,8 @@ private:
     bool flag_GGTO_2{};
     bool flag_GGTO_3{};
     bool flag_GGTO_4{};
+
+    bool flag_CED{};
 };
 
 

src/core/system_parameters/galileo_reduced_ced.cc

@@ -0,0 +1,56 @@
+/*!
+ * \file galileo_reduced_ced.cc
+ * \brief Galileo Reduced Clock and Ephemeris Data storage class
+ * \author Carles Fernandez, 2021. cfernandez(at)cttc.cat
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
+ * This file is part of GNSS-SDR.
+ *
+ * Copyright (C) 2010-2021  (see AUTHORS file for a list of contributors)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * -----------------------------------------------------------------------------
+ */
+
+#include "galileo_reduced_ced.h"
+#include "MATH_CONSTANTS.h"
+#include <cmath>
+
+
+Galileo_Ephemeris Galileo_Reduced_CED::compute_eph() const
+{
+    Galileo_Ephemeris eph{};
+
+    const double A_nominal = 29600000;  // meters (Table 1 Galileo ICD 2.0)
+    const double Ared = DeltaAred + A_nominal;
+    eph.sqrtA = std::sqrt(Ared);    // Square root of the semi-major axis [meters^1/2]
+    const double i_nominal = 56.0;  // degrees (Table 1 Galileo ICD 2.0)
+    const double i0red = Deltai0red + i_nominal / 180.0;
+    eph.i_0 = i0red;                                     // Inclination angle at reference time  [semi-circles]
+    eph.ecc = std::sqrt(exred * exred + eyred * eyred);  // Eccentricity
+    const double omega_semicircles = std::atan2(eyred, exred) / GNSS_PI;
+    eph.omega = omega_semicircles;             // Argument of perigee [semi-circles]
+    eph.M_0 = lambda0red - omega_semicircles;  // Mean anomaly at reference time [semi-circles]
+    eph.OMEGA_0 = Omega0red;                   // Longitude of ascending node of orbital plane at weekly epoch [semi-circles]
+
+    eph.flag_all_ephemeris = true;
+    eph.IOD_ephemeris = IODnav;
+    eph.IOD_nav = IODnav;
+    eph.PRN = PRN;
+
+    int32_t t0r = (30 * (TOTRedCED / 30) + 1) % 604800;
+    eph.toe = t0r;  // Ephemeris reference time [s]
+
+    // Clock correction parameters
+    eph.toc = t0r;     // Clock correction data reference Time of Week [sec]
+    eph.af0 = af0red;  // SV clock bias correction coefficient [s]
+    eph.af1 = af1red;  // SV clock drift correction coefficient [s/s]
+
+    // GST
+    eph.WN = TOTRedCED / 604800;   // Week number
+    eph.tow = TOTRedCED % 604800;  // Time of Week
+
+    return eph;
+}

src/core/system_parameters/galileo_reduced_ced.h

@@ -0,0 +1,62 @@
+/*!
+ * \file galileo_reduced_ced.h
+ * \brief Galileo Reduced Clock and Ephemeris Data storage class
+ * \author Carles Fernandez, 2021. cfernandez(at)cttc.cat
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
+ * This file is part of GNSS-SDR.
+ *
+ * Copyright (C) 2010-2021  (see AUTHORS file for a list of contributors)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * -----------------------------------------------------------------------------
+ */
+
+
+#ifndef GNSS_SDR_GALILEO_REDUCED_CED_H
+#define GNSS_SDR_GALILEO_REDUCED_CED_H
+
+#include "galileo_ephemeris.h"
+#include <cstdint>
+
+/** \addtogroup Core
+ * \{ */
+/** \addtogroup System_Parameters
+ * \{ */
+
+
+/*!
+ * \brief This class manages the Galileo Reduced Clock and Ephemeris Data
+ */
+class Galileo_Reduced_CED
+{
+public:
+    /*!
+     * Default constructor
+     */
+    Galileo_Reduced_CED() = default;
+
+    /*!
+     * Convert to Galileo_Ephemeris
+     */
+    Galileo_Ephemeris compute_eph() const;
+
+    uint32_t PRN{};       //!< Satellite ID
+    int32_t TOTRedCED{};  //!< Start time of transmission of the Reduced CED word in GST
+    int32_t IODnav{};     //!< Issue of Data
+    double DeltaAred{};   //!< Difference between the Reduced CED semi-major axis and the nominal semi-major axis [meters]
+    double exred{};       //!< Reduced CED eccentricity vector component x
+    double eyred{};       //!< Reduced CED eccentricity vector component y
+    double Deltai0red{};  //!< Difference between the Reduced CED inclination angle at reference time and the nominal inclination [semi-circles]
+    double Omega0red{};   //!< Reduced CED longitude of ascending node at weekly epoch [semi-circles]
+    double lambda0red{};  //!< Reduced CED mean argument of latitude [semi-circles]
+    double af0red{};      //!< Reduced CED satellite clock bias correction coefficient [seconds]
+    double af1red{};      //!< Reduced CED satellite clock drift correction coefficient [seconds/seconds]
+};
+
+
+/** \} */
+/** \} */
+#endif  // GNSS_SDR_GALILEO_REDUCED_CED_H