Localization with an a priori Map

Abstract

This chapter concerns the use of MSIS to solve the localization problem for an underwater vehicle navigating in a structured environment when an a priori map is available. The initial objective of this work was to develop a system to locate the Ictineu AUV within the square water tank which served as the theatre of operation during the SAUC-E competition. The availability of such a localization system made it possible to pre-define a series of waypoints to be followed by the vehicle and therefore optimize the exploration of the scenario in search of the various necessary targets to accomplish the proposed tasks. However, solving the navigation problem for an AUV moving in a water tankwas not only useful for the SAUC-E competition. Further work has been undertaken to develop improved localization algorithms to work under laboratory conditions, since we believe that such a system opens the door to further advanced control experiments.

Section 5.1 reviews different strategies to perform data association in localization problems, while Sections 5.2 and 5.3 present two map-based localization methods developed for the competition. The first is a simple algorithm which determines the vehicle’s position by means of a voting strategy, while the second relies on an EKF to merge the information from several sensors and the tank map. A third method, which combines several aspects of the two other algorithms to improve the estimation process, is presented in Section 5.4. The chapter concludes with a summary of the advantages of the different methods and some guidelines for further work.