NavList:

This is one for you mathematicians to ponder.  Smartphone and Raspberry Pie sextants have been suggested before.  They’ve been discounted by receiver experts, because the onboard sensors are just not accurate enough to give a decent vertical. However, maybe the clue is in ‘Once the altitudes of several stars, or the moon, and sun are determined, the smartphone navigation app can map your position.’ What if the app is applying the same mathematics which is used to slew the receiver clock to ensure the GNSS tetrahedron shrinks to a point?  Might the same mathematics be used to slew the smartphone vertical until the three or four position lines meet at a point? And for Bill Lionheart, which point would this be?  Just a thought. DaveP