A method and system is disclosed for determining a flight characteristic
of an object in a flight path, the flight characteristic to be determined
can be the object's position while in flight, a linear velocity, a
rotational velocity or an acceleration of the object. In one embodiment,
the method comprises arranging a radiation source in a plane, the plane
being located to intersect the flight path of the object. The radiation
source irradiates the object at least at the intersection with the flight
path. The object is provided with at least first and second surface
features having a predetermined configuration such as, for example,
equally spaced parallel lines painted on the surface of the object.
Reflected radiation from the object is measured with a sensor from the
surface features and a flight characteristic of the object is determined
based on the measured reflected radiation and the predetermined
configuration of the surface features.