AP_NavEKF : Mavlink tunable parameter - first attempt

libraries/AP_NavEKF/AP_NavEKF.cpp

@@ -21,6 +21,19 @@ extern const AP_HAL::HAL& hal;
 
 #define earthRate 0.000072921f // earth rotation rate (rad/sec)
 
+// Define tuning parameters
+const AP_Param::GroupInfo AP_NavEKF::var_info[] PROGMEM = {
+
+    // @Param: TEST PARAM
+    // @DisplayName: Blah (units)
+    // @Description: Blah blah.
+	// @Increment: 0.1
+	// @User: advanced
+    AP_GROUPINFO("BLAH",    0, AP_NavEKF, _blah, 1.0f),
+
+    AP_GROUPEND
+};
+
 // constructor
 NavEKF::NavEKF(const AP_AHRS *ahrs, AP_Baro &baro) :
     _ahrs(ahrs),

libraries/AP_NavEKF/AP_NavEKF.h

@@ -26,6 +26,7 @@
 #include <AP_Baro.h>
 #include <AP_Airspeed.h>
 #include <AP_Compass.h>
+#include <AP_Param.h>
 
 // #define MATH_CHECK_INDEXES 1
 
@@ -254,6 +255,9 @@ public:
     uint32_t _hgtRetryTimeMode12;   // height measurement retry time following innovation consistency fail if GPS fusion mode is > 0
 
 private:
+    // EKF tuneable parameters
+    AP_Float _blah;
+
     bool statesInitialised;         // boolean true when filter states have been initialised
     bool staticModeDemanded;        // boolean true when staticMode has been demanded externally.
     bool velHealth;                 // boolean true if velocity measurements have failed innovation consistency check