diff --git a/libraries/AP_AHRS/AP_AHRS.h b/libraries/AP_AHRS/AP_AHRS.h
index 0d44f6d9a1..ed0457ab9a 100644
--- a/libraries/AP_AHRS/AP_AHRS.h
+++ b/libraries/AP_AHRS/AP_AHRS.h
@@ -107,7 +107,14 @@ public:
 		return Vector3f(0,0,0);
 	}
 
+	// return true if yaw has been initialised
+	bool yaw_initialised(void) { 
+		return _have_initial_yaw;
+	}
+
 protected:
+	// whether the yaw value has been intialised with a reference
+	bool		_have_initial_yaw;
 
 	// pointer to compass object, if available
 	Compass 	* _compass;
diff --git a/libraries/AP_AHRS/AP_AHRS_DCM.h b/libraries/AP_AHRS/AP_AHRS_DCM.h
index 885c18f8b7..79dd774d82 100644
--- a/libraries/AP_AHRS/AP_AHRS_DCM.h
+++ b/libraries/AP_AHRS/AP_AHRS_DCM.h
@@ -64,7 +64,6 @@ public:
 private:
 	float		_ki;
 	float		_ki_yaw;
-	bool		_have_initial_yaw;
 
 	// Methods
 	void 		matrix_update(float _G_Dt);
diff --git a/libraries/AP_AHRS/AP_AHRS_MPU6000.h b/libraries/AP_AHRS/AP_AHRS_MPU6000.h
index 0a3aa8e8c3..7cbe8bdc3b 100644
--- a/libraries/AP_AHRS/AP_AHRS_MPU6000.h
+++ b/libraries/AP_AHRS/AP_AHRS_MPU6000.h
@@ -67,7 +67,6 @@ public:
 private:
 	float		_ki;
 	float		_ki_yaw;
-	bool		_have_initial_yaw;
 	AP_InertialSensor_MPU6000	*_mpu6000;
 
 	// Methods
diff --git a/libraries/AP_AHRS/AP_AHRS_Quaternion.h b/libraries/AP_AHRS/AP_AHRS_Quaternion.h
index 91c41e2ea4..fe322e3958 100644
--- a/libraries/AP_AHRS/AP_AHRS_Quaternion.h
+++ b/libraries/AP_AHRS/AP_AHRS_Quaternion.h
@@ -58,8 +58,6 @@ private:
 	void 		update_IMU(float deltat, Vector3f &gyro, Vector3f &accel);
 	void 		update_MARG(float deltat, Vector3f &gyro, Vector3f &accel, Vector3f &mag);
 
-	bool		_have_initial_yaw;
-
 	// Methods
 	void 		accel_adjust(void);