There have been discussions before calling for reliable and accurate alternatives to GPS. The Vikings may have had the answer without knowing the physics. They were adept navigators at latitudes where frequent cloudiness and low sun angle(winter) could have made direct observation of the sun difficult. Legend has it that they had a magic stone, called a Sunstone, that allowed them to navigate by the sun even after dark. You're wondering how maybe, and I'm wondering when will this be available on a chip.