Accurate positioning for real-time control purpose integration of GPS, NAV200 and encoder data

Positioning of a mobile robot is critical to its movement in an outdoor environment to accomplish tasks with success and accuracy. For outdoor automation with a fleet of mobile robots in a local area, a common positioning system for all vehicles is essential for maneuvering and coordination. The positioning system should be referenced to a global coordinate frame and requires few artificial landmarks only for the areas that are out of the GPS positioning system. In addition, positioning system is desirable to have a high update rate for real-time control purposes. In this paper, we propose an integrated positioning system (IPS), which is able to provide an accurate and high update rate position estimate. The integrated system utilizes GPS as the global coordinate positioning system, Nav200 as the local positioning system for areas that are not covered by GPS signals and encoders/compass as the supplementary relative positioning system. The structure of the IPS and techniques are described. Experimental results are presented to show the working and output of the IPS.