Actually the tilt of the earth and the fact that we circle the sun has nothing to do with it. The stars they saw 40,000 years ago would not be in the same place they are today as they will not be in the same place in another 40,000 years. This has to do with their positions in the milky way galaxy that we are part of and other galaxies they are part of due to the still expanding universe and the drift potential of the stars from their current positions.
I can see that ancient man just like modern man have used stars to get around and to mark time and days.