In this paper we present two approaches for tracking of people in dynamic environments with a moving sensor system. The trajectories of persons are used to extract simple motion patterns. Object detection and tracking is based on range and color information which is provided by a laser range finder and a omnidirectional color camera. Without any predefined person-model the system acquires an internal representation of the person at an initialization phase. This representation is tracked in real-time in dynamic environments. During the tracking procedure illumination conditions are continuously monitored. The tracking approaches were implemented on a robotic wheelchair and evaluated experimentally in different dynamic environments.