From 07a8a985c458acc45815fae69623b95aefc5b326 Mon Sep 17 00:00:00 2001
From: Carles Fernandez <carles.fernandez@cttc.es>
Date: Thu, 5 Mar 2026 08:00:07 +0100
Subject: [PATCH] Fix PRN in QZSS L5 ephemeris

---
 .../system_parameters/gps_cnav_navigation_message.cc | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/core/system_parameters/gps_cnav_navigation_message.cc b/src/core/system_parameters/gps_cnav_navigation_message.cc
index 6c2c6be39..66df5de45 100644
--- a/src/core/system_parameters/gps_cnav_navigation_message.cc
+++ b/src/core/system_parameters/gps_cnav_navigation_message.cc
@@ -18,9 +18,8 @@
 
 #include "gps_cnav_navigation_message.h"
 #include "gnss_satellite.h"
-#include <cmath>   // for std::sqrt
-#include <limits>  // for std::numeric_limits
-
+#include <cmath>     // for std::sqrt
+#include <limits>    // for std::numeric_limits
 
 Gps_CNAV_Navigation_Message::Gps_CNAV_Navigation_Message(CnavSystem system)
     : d_system(system)
@@ -81,7 +80,11 @@ void Gps_CNAV_Navigation_Message::decode_page(const std::bitset<GPS_CNAV_DATA_PA
     bool alert_flag;
 
     // common to all messages
-    const auto PRN = static_cast<int32_t>(read_navigation_unsigned(data_bits, CNAV_PRN));
+    auto PRN = static_cast<int32_t>(read_navigation_unsigned(data_bits, CNAV_PRN));
+    if (d_system == CnavSystem::QZSS)
+        {
+            PRN += 192;
+        }
     ephemeris_record.PRN = PRN;
 
     d_TOW = static_cast<int32_t>(read_navigation_unsigned(data_bits, CNAV_TOW));
@@ -93,7 +96,6 @@ void Gps_CNAV_Navigation_Message::decode_page(const std::bitset<GPS_CNAV_DATA_PA
 
     page_type = static_cast<int32_t>(read_navigation_unsigned(data_bits, CNAV_MSG_TYPE));
 
-
     switch (page_type)
         {
         case 10:  // Ephemeris 1/2