You need a phisical phone to test this. iOS simulator doesn't work.
When launching on an iPhone we get this kind of data:
Position: <5900d0f4 b8f1bec4 c0fff3ff 55ff>
Position: <59006c01 4cf322bf c2ffecff 53ff>
Position: <5900b804 8cf900c2 c7ffeaff 51ff>
Position: <5900f602 c2fffebe c7ffeeff af00>
Position: <59008602 200172c0 c6ffefff af00>
Position: <5900d8fb 26fdb8c0 c5fff1ff b000>
Position: <5900f801 64ff7cc0 c4fff2ff b100>
Position: <59009c01 60ff46c0 c4fff3ff b100>
Position: <5900f201 84ff16c0 c4fff4ff b100>
Position: <5900a601 82ffdabf c5fff5ff b200>
Position: <5900f601 caff12c0 c5fff6ff b200>
Position: <5900d401 9effaebf c6fffbff b300>
Position: <59001602 f2ffa4bf c6fffbff b300>
Position: <59000e02 c0ffc4bf c6fffcff b300>
Position: <5900a401 82ff14c0 c6fffcff b300>
Position: <59009601 60ffe4bf c7fffdff b300>
Position: <59000a02 60ffaebf c7fffdff 4dff>
Position: <5900d601 d2ff28c0 c7fffeff 4dff>
More info: http://www.hackster.io/cedric/twi