AP_Vehicle: instantiate the AHRS object

libraries/AP_Vehicle/AP_Vehicle.h

@@ -136,6 +136,15 @@ protected:
     // false disables external leds)
     AP_Notify notify;
 
+    // Inertial Navigation EKF
+#if AP_AHRS_NAVEKF_AVAILABLE
+    NavEKF2 EKF2{&ahrs, rangefinder};
+    NavEKF3 EKF3{&ahrs, rangefinder};
+    AP_AHRS_NavEKF ahrs{EKF2, EKF3};
+#else
+    AP_AHRS_DCM ahrs;
+#endif
+
 private:
 
     static AP_Vehicle *_singleton;