Get PVT fixes from a standalone Galileo E5b receiver

GnssTao · Feb 10, 2022 · df1820e · df1820e
1 parent 7a0259f
commit df1820e
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Showing 4 changed files with 25 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -36,8 +36,9 @@ In the L2 band:
 
 In the L5 band:
 
-- &#128752; GPS L5 (centered at 1176.45 MHz) :white_check_mark:
-- &#128752; Galileo E5a (centered at 1176.45 MHz) :white_check_mark:
+- &#128752; Galileo E5b (centered at 1207.140 MHz) :white_check_mark:
+- &#128752; Galileo E5a (centered at 1176.450 MHz) :white_check_mark:
+- &#128752; GPS L5 (centered at 1176.450 MHz) :white_check_mark:
 
 GNSS-SDR provides interfaces for a wide range of radio frequency front-ends and
 raw sample file formats, generates processing outputs in standard formats,
@@ -1662,6 +1663,7 @@ identifiers:
 | Glonass L2 C/A |       2G       |
 | GPS L5         |       L5       |
 | Galileo E5a    |       5X       |
+| Galileo E5b    |       7X       |
 
 Example: Eight GPS L1 C/A channels.
 

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
@@ -16,6 +16,8 @@ All notable changes to GNSS-SDR will be documented in this file.
 
 ### Improvements in Availability:
 
+- Added the Galileo E5b receiving chain. The software is now able to compute PVT
+  solutions as a standalone Galileo E5b receiver.
 - Improved Time-To-First-Fix when using GPS L1 C/A signals, fixing a bug that
   was making the receiver to drop the satellite if the PLL got locked at 180
   degrees, and making some optimizations on bit transition detection.

diff --git a/src/algorithms/PVT/libs/rtklib_solver.cc b/src/algorithms/PVT/libs/rtklib_solver.cc
@@ -406,6 +406,7 @@ bool Rtklib_Solver::get_PVT(const std::map<int, Gnss_Synchro> &gnss_observables_
     bool gps_dual_band = false;
     bool band1 = false;
     bool band2 = false;
+    bool gal_e5_is_e5b = false;
     for (gnss_observables_iter = gnss_observables_map.cbegin();
          gnss_observables_iter != gnss_observables_map.cend();
          ++gnss_observables_iter)
@@ -468,7 +469,7 @@ bool Rtklib_Solver::get_PVT(const std::map<int, Gnss_Synchro> &gnss_observables_
                             }
 
                         // Galileo E5
-                        if (sig_ == "5X")
+                        if ((sig_ == "5X") || (sig_ == "7X"))
                             {
                                 // 1 Gal - find the ephemeris for the current GALILEO SV observation. The SV PRN ID is the map key
                                 galileo_ephemeris_iter = galileo_ephemeris_map.find(gnss_observables_iter->second.PRN);
@@ -508,6 +509,10 @@ bool Rtklib_Solver::get_PVT(const std::map<int, Gnss_Synchro> &gnss_observables_
                                     {
                                         DLOG(INFO) << "No ephemeris data for SV " << gnss_observables_iter->second.PRN;
                                     }
+                                if (sig_ == "7X")
+                                    {
+                                        gal_e5_is_e5b = true;
+                                    }
                             }
                         break;
                     }
@@ -874,7 +879,15 @@ bool Rtklib_Solver::get_PVT(const std::map<int, Gnss_Synchro> &gnss_observables_
                 {
                     for (int j = 0; j < NFREQ; j++)
                         {
-                            nav_data.lam[i][j] = satwavelen(i + 1, j, &nav_data);
+                            if (j == 2 && gal_e5_is_e5b)
+                                {
+                                    // frq = 4 corresponds to E5B in that function
+                                    nav_data.lam[i][j] = satwavelen(i + 1, 4, &nav_data);
+                                }
+                            else
+                                {
+                                    nav_data.lam[i][j] = satwavelen(i + 1, j, &nav_data);
+                                }
                         }
                 }
 

diff --git a/src/algorithms/libs/rtklib/rtklib_conversions.cc b/src/algorithms/libs/rtklib/rtklib_conversions.cc
@@ -71,6 +71,10 @@ obsd_t insert_obs_to_rtklib(obsd_t& rtklib_obs, const Gnss_Synchro& gnss_synchro
             break;
         case 'E':
             rtklib_obs.sat = gnss_synchro.PRN + NSATGPS + NSATGLO;
+            if (sig_ == "7X")
+                {
+                    rtklib_obs.code[band] = static_cast<unsigned char>(CODE_L7X);
+                }
             break;
         case 'R':
             rtklib_obs.sat = gnss_synchro.PRN + NSATGPS;