Active cross-path correlation for autonomous vehicle path following

There are several applications where it is advantageous for a follower vehicle to closely repeat the path established by a leader vehicle. Common examples include platooning and convoying. In some of these applications, the leader vehicle cannot be directly sensed by the follower vehicle, and thus the follower must rely on a recorded representation of the leader's path. This implies a common position reference for both vehicles.; There are no current position estimation systems with both the precision and flexibility required for either indoor or outdoor urban path following operation. Radio beacon systems and GPS either require expensive infrastructure or lack accuracy and/or coverage. Inertial systems and dead-reckoning systems accumulate errors proportional to either time (inertial) or distance traveled (dead reckoning). Guide-wire and known-point update systems are too restrictive, and the infrastructure may be too expensive.; We have developed and demonstrated a technique to use a dead-reckoning position-estimating system in both the leader and follower vehicles (which may be the same vehicle re-traversing its own path). The leader records the range-to-obstruction to either or both sides as well as vehicle position and orientation estimate. A non-model-based correlation technique is used to correlate the follower's trajectory and side-range profile to the leader's. The technique is tolerant of changes in the environment between passes of the leader and follower, and eliminates the correspondence problem in a model-based system where both the leader and follower need to correctly identify a particular object as being the same landmark.; The principles used in this technique can be easily generalized to update a dead-reckoning navigator for a robot operating within a known area, such as a room or warehouse. This is especially useful because the technique is usable in a dynamic environment.