Methods are provided where: a signal is transmitted from an illuminating
source and received cavity waveguides disposed on an object; a position
and/or orientation of the object is determined based on the signal
received in the waveguides; and data representing the determined position
and/or orientation is transmitted to a remote location or generated for
use in the object. The illuminating source can also be moved to indicate
a change in a predetermined trajectory or target position where a new
position and/or orientation of the object is determined based on the
signal received in the waveguides and the object is controlled to change
the predetermined trajectory or target position to the indicated new
predetermined trajectory or new target position. A change can also be
detected in the predetermined trajectory or target position and the
object controlled to correct the change.