> how will it determine its position without a reference It won't. It needs a starting position from an external source, and without periodic updates from some

> how will it determine its position without a reference It won't. It needs a starting position from an external source, and without periodic updates from some external source, errors will build up in this system just as with any inertial navigation system. As I understand it, this system is just supposed to build up errors much more slowly than existing inertial navigation systems, so it can go longer between updates from an external source before its error becomes too large to be acceptable.