A Fast Onboard Relative Positioning Module for Multirobot Systems

We present an onboard robotic module that can determine relative positions among miniature robots. The module uses high-frequency-modulated infrared emissions to enable nearby robots to determine the range, bearing, and message of the sender with a rapid update rate. A carrier sense multiple access protocol is employed for scalable operation. We describe a technique for calculating the range and bearing between robots, which can be generalized for use with more sophisticated relative positioning systems. Using this method, we characterize the accuracy of positioning between robots and identify different sources of imprecision. Finally, the utility of this module is clearly demonstrated with several robotic formation experiments, where precise multirobot formations are maintained throughout difficult maneuvers.