Autonomous navigation refers to navigating without satellite signals. It is needed inside buildings and tunnels (shielding) as well as for the exploration of other planets. The appropriate methods have many commonalities and are therefore grouped together within one mission.
Simultaneous localisation and mapping
Pedestrians in corporate or administrative buildings, shopping centers, and transit subway stations need guidance to reach their destination quickly. Due to the complex ownership and business relations in large buildings, it is typically difficult to install and operate a positioning infrastructure. Even the provision of up-to-date maps is an almost unsolvable problem. Therefore, the institute has developed methods for infrastructurefree positioning and mapping. The sensors consist of inertial measuring units and magnetometers, and their measurements are turned into positions and maps through Bayesian estimation processes. These maps show routes through buildings. They do not generate a floor plan in a traditional sense but this is not needed. Routes are sufficient for navigation. The accuracy of the mapping increases with the amount of data reported during the usage of the building. Industry has shown great interest in this technology as developed at the institute.
The mapping of unknown territory and the search for water or organic molecules are typical tasks for exploratory missions. Today, large rovers controlled from Earth are used for exploration. However, this approach is inherently slow, since the time for a signal to reach Mars may be up to 20 minutes. It also requires a permanent radio link between the rover and the controller. The associated constraints prompted the institute to develop a new concept. It uses many small rovers or crawlers, which cooperate and take decisions autonomously. The individual swarm elements measure their relative positions using radio signals and possibly other sensors to avoid collisions. In addition, they sense their environment with cameras, radar, Geiger counters, gas detectors and other analyzers, and exchange their findings. In this way, they develop a joint model of the environment. Areas where the parameters of interest are essentially constant are less interesting for further exploration. Exploring them in more detail would be a waste of resources. As a consequence, the exploration strategies developed at the institute focus on maximizing the entropy. Recently, a swarm could be programed to perform an exploration task cooperatively but in a completely decentralized manner. This makes for a very robust system in which individual rovers may even drop out without endangering the mission.