Plane : NavEKF Mavlink tunable parameter - first attempt

ArduPlane/Parameters.h

@@ -153,6 +153,9 @@ public:
         k_param_barometer,   // barometer ground calibration
         k_param_airspeed,  // AP_Airspeed parameters
         k_param_curr_amp_offset,
+#if AP_AHRS_NAVEKF_AVAILABLE
+        k_param_NavEKF,  // Extended Kalman Filter Inertial Navigation Group
+#endif
 
         //
         // 150: Navigation parameters

ArduPlane/Parameters.pde

@@ -973,6 +973,12 @@ const AP_Param::Info var_info[] PROGMEM = {
     GOBJECT(obc,  "FS_", APM_OBC),
 #endif
 
+#if AP_AHRS_NAVEKF_AVAILABLE
+    // @Group: EKF_
+    // @Path: ../libraries/AP_NavEKF/AP_NavEKF.cpp
+    GOBJECT(NavEKF, "EKF_", AP_NavEKF),
+#endif
+
     AP_VAREND
 };