title: IOS ARKit Swift how can I get distance between me and a SCNNode when I move
body: <p>I have an issue with ARkit, I use ARWorldTrackingConfiguration and when I have a SCNNode one meter away from me, when I use Iphone X and move to the SCNNode, the Z position of my camera SCNNode updates and I know that I am closer to the node, but with other Iphones (Iphone 8) I don't get an update to Z position.</p>
  
  <p>Also with GPS even with kCLLocationAccuracyBestForNavigation I don't have accuracy. </p>
  
  <p>How can I know that I am closer to the SCNNode?? Thank you</p>