AP_Notify: add gps glitch notification

libraries/AP_Notify/AP_Notify.h

@@ -76,6 +76,7 @@ public:
         uint32_t leak_detected      : 1;    // 1 if leak detected
         float    battery_voltage       ;    // battery voltage
         uint32_t gps_fusion         : 1;    // 0 = GPS fix rejected by EKF, not usable for flight. 1 = GPS in use by EKF, usable for flight
+        uint32_t gps_glitching      : 1;    // 1 if gps is glitching
 
         // additional flags
         uint32_t external_leds      : 1;    // 1 if external LEDs are enabled (normally only used for copter)

libraries/AP_Notify/RGBLed.cpp

@@ -180,7 +180,7 @@ void RGBLed::update_colours(void)
     // gps failsafe pattern : flashing yellow and blue
     // ekf_bad pattern : flashing yellow and red
     if (AP_Notify::flags.failsafe_radio || AP_Notify::flags.failsafe_battery ||
-            AP_Notify::flags.ekf_bad || AP_Notify::flags.leak_detected) {
+            AP_Notify::flags.ekf_bad || AP_Notify::flags.gps_glitching || AP_Notify::flags.leak_detected) {
         switch(step) {
             case 0:
             case 1:
@@ -207,6 +207,11 @@ void RGBLed::update_colours(void)
                     _red_des = brightness;
                     _blue_des = _led_off;
                     _green_des = _led_off;
+                } else if (AP_Notify::flags.gps_glitching) {
+                    // blue on gps glitch
+                    _red_des = _led_off;
+                    _blue_des = brightness;
+                    _green_des = _led_off;
                 }else{
                     // all off for radio or battery failsafe
                     _red_des = _led_off;