The aim of the Unmanned Ground Vehicle (UGV) project at the University of Massachusetts is to develop a system capable of navigating both on-road and cross country, avoiding obstacles, and determining its position using landmarks. Complex problems, such as driving, can be solved more easily by decomposing them into smaller sub-problems, solving each sub-problem, and then integrating the solutions. In the case of an autonomous vehicle, the integrated system should be able to \react" in real time to a changing environment and to \reason" about ways to achieve its goals. This paper describes the approach taken on the UMass Mobile Perception Laboratory (MPL) to integrate independent processes (each solving a particular aspect of the navigation problem) into a fully capable autonomous vehicle.