Location based AR with Vuforia unity3d plugin

Question

I successfully integrated Vuforia plugin in unity3d, I set World Center Mode of Vuforia AR Camera object in scene to DEVICE_TRACKING to apply handheld device rotation to AR Camera object, it works fine and when I look around by my android mobile phone the Vuforia AR camera move in the scene too.
I set my location markers (Point of Interests) in their location in unity scene where x = latitude and z = longitude and set AR Camera transform.position to Input.location.lastData on each frame so when user move in real world the AR Camera also moves in unity scene, so far everything is OK!
the problem is here : How set x and z axis of unity scene to real world North and East axis ?
each time I run the app the my markers have different position in real world! I think Vuforia AR camera assume initial angle of the camera as North.

in image you see Point1 AR Marker which remain at same point when I rotate device camera, but I want it to be at north , each time I run the app it is at my forward not on real world North axis
I use Unity 5.6.1f1 and Vuforia 6.2.6.

Edit:
How can I set unity Z axis point to real world North and unity X axis points to real world East?