AP_Notify: add gps glitching and failsafe flags

libraries/AP_Notify/ToneAlarm_PX4.cpp

@@ -85,6 +85,24 @@ void ToneAlarm_PX4::update()
             play_tune(TONE_BATTERY_WARNING_FAST_TUNE);
         }
     }
+
+    // check gps glitch
+    if (flags.gps_glitching != AP_Notify::flags.gps_glitching) {
+        flags.gps_glitching = AP_Notify::flags.gps_glitching;
+        if (flags.gps_glitching) {
+            // gps glitch warning tune
+            play_tune(TONE_GPS_WARNING_TUNE);
+        }
+    }
+
+    // check gps failsafe
+    if (flags.failsafe_gps != AP_Notify::flags.failsafe_gps) {
+        flags.failsafe_gps = AP_Notify::flags.failsafe_gps;
+        if (flags.failsafe_gps) {
+            // gps glitch warning tune
+            play_tune(TONE_GPS_WARNING_TUNE);
+        }
+    }
 }
 
 #endif // CONFIG_HAL_BOARD == HAL_BOARD_PX4

libraries/AP_Notify/ToneAlarm_PX4.h

@@ -39,6 +39,8 @@ private:
     struct tonealarm_type {
         uint8_t armed              : 1;    // 0 = disarmed, 1 = armed
         uint8_t failsafe_battery   : 1;    // 1 if battery failsafe
+        uint8_t gps_glitching      : 1;    // 1 if gps position is not good
+        uint8_t failsafe_gps       : 1;    // 1 if gps failsafe
     } flags;
 };