  Linear Collider Alignment and Survey (LiCAS) R&D group is proposing a novel
automated metrology instrument dedicated to align and monitor the mechanical
stability of a future linear high energy e+e- collider. LiCAS uses Laser
Straightness Monitors (LSM) and Frequency Scanning Interferometry (FSI) for
straightness and absolute distance measurements, respectively. This paper
presents detailed simulations of a LiCAS system operating inside a Rapid Tunnel
Reference Surveyor (RTRS train). With the proposed design it is feasible to
achieve the required vertical accuracy of the order of 200 micons over 600 m
tunnel sections meeting the specification for the TESLA collider.
