Towards a Radio-Based Swarm Navigation System on Mars – Key Technologies and Performance Assessment

Kurzfassung

Robust localization and navigation are essential for the success of robotic exploration, especially in remote and harsh environments. Navigation in feature-less areas becomes challenging when laser scanners or cameras can not provide relative or global localization. Moreover, complementary positioning solutions like a Global Navigation Satellite System or mobile radio based localization are not available on Mars. State of the art systems focus on single partial autonomous robots for specific scientific tasks, e.g., the Curiosity rover. We propose autonomous robotic swarms as promising approach to explore the Valles Marineris canyon system. Our swarm navigation uses relative radio positioning and return-tobase navigation, exploiting wireless signals in a smart fashion and aims to complement existing laser/camera based solutions. It employs a hybrid time-division access and frequency-division multiple access scheme with interleaved round-trip delay ranging measurements. Ranging measurements are online processed in a distributed particle filter with local, partial connectivity to surrounding swarm elements. Furthermore, our swarm navigation is jointly designed for localization and communication. Thus, the very same wireless links used for ranging are simultaneously used for high-rate communications among swarm elements. The performance of our approach is evaluated through simulations and with real measurement data obtained from our ranging prototype. We achieve sub-meter accuracy for anchorfree localization which highlights our promising and applicable solution for robotic swarms.