Hi,
I was reading about the "relativistic hall effect":
It shows an asymmetrical relativistic effect that should be able to be measured and thus determine the absolute direction of motion and also the velocity:
That link shows the relativistic hall effect of a flywheel translating at relativistic speeds while at the same time rotating on its axis radially to the direction of translation. If the flywheel is stationary there is no asymmetrical effect from the rotation, but if the flywheel rotation occurs during relativistic translation then the flywheel will undergo an asymmetrical Lorentz transformation, ie. length contraction and mass increase on the side of the flywheel that has a rotational velocity that increases with the translating motion, and length stretching and mass decrease on the side of the flywheel that has a rotational velocity that decreases with the translating motion. If a clock was put on one of the flywheel spokes, it should then count slower on the flywheel side that is rotating towards the direction of the translating motion. So if you have three of these flywheels like a 3axis gyroscope, you could use them as a 3axis relativistic translation detection device!
cheers, Jamie