  Lock acquisition of a suspended optical cavity can be a highly stochastic
process and is therefore nontrivial. Guided lock is a method to make lock
acquisition less stochastic by decelerating the motion of the cavity length
based on an extrapolation of the motion from an instantaneous velocity
measurement. We propose an improved scheme which is less susceptible to seismic
disturbances by incorporating the acceleration as a higher order correction in
the extrapolation. We implemented the new scheme in a 300-m suspended
Fabry-Perot cavity and improved the success rate of lock acquisition by a
factor of 30.
