Add leap seconds to raw GPS time

src/config.h

@@ -57,6 +57,9 @@
 // Threshold for time-synchronized modes regarding how far from scheduled transmission time the transmission is still allowed
 #define RADIO_TIME_SYNC_THRESHOLD_MS 2000
 
+// Number of leap seconds to add to the raw GPS time reported by the GPS chip (see https://timetoolsltd.com/gps/what-is-gps-time/ for more info)
+#define GPS_TIME_LEAP_SECONDS 18
+
 // Enable this setting to require 3D fix (altitude required, enable for airborne use), otherwise 2D fix is enough
 #define GPS_REQUIRE_3D_FIX true
 

src/radio.c

@@ -712,7 +712,7 @@ bool radio_handle_time_sync()
         return false;
     }
 
-    uint32_t time_millis = gps.time_of_week_millis;
+    uint32_t time_millis = gps.time_of_week_millis + (GPS_TIME_LEAP_SECONDS * 1000);
 
     if (time_millis == radio_previous_time_sync_scheduled) {
         // The GPS chip has not provided an updated time yet for some reason