Regarding dead reckoning - http://www.telegraph.co.uk/technology/news/10833087/MoD-creates-coldest-object-in-the-universe-to-trump-GPS.html http://www.telegraph

Regarding dead reckoning - http://www.telegraph.co.uk/technology/news/10833087/MoD-creates-coldest-object-in-the-universe-to-trump-GPS.html http://www.telegraph.co.uk/technology/news/10833087/MoD-crea... seems very interesting. If anyone has any up to date information or papers on this approach, I'd be very interested. (It seems to be also known as a quantum compass)