Radio Localization for Robotic Planetary Exploration: Lessons Learned from a Space-Analogue Mission

Kurzfassung

Autonomous robotic systems will be the future of planetary exploration missions. For autonomous robotic exploration, reliable pose estimation is required. This is provided by cooperative radio localization, where radio signals are exchanged among the robots and other mission entities. Range and direction information is obtained by measuring the signal round-trip time (RTT) and direction-of-arrival (DoA), which enables position and orientation estimation of the robots. For the first time, we have demonstrated cooperative radio localization within a space-analogue exploration mission with two robotic rovers on the volcano Mt Etna. With this paper, we share our main lessons learned and provide tangible numbers on the localization accuracy in a realistic environment. By thoroughly evaluating the measurement data, we identify estimation biases as the main error source. We then show how to estimate and compensate the biases during the mission by simultaneous localization and calibration (SLAC). We further demonstrate the benefit of cooperation and the feasibility of single-link localization.