Tether-Based Localization for Cooperative Ground and Aerial Vehicles

Considering a multi-robot system composed of a ground vehicle and a multi-copter connected each other with a tether, it is crucial for them to know their relative positions in order to carry out any operating task. Localization is usually accomplished by using GPS in outdoor environments. However, such a system does not work in indoor and more generally in so-called GPS denied environments. We investigated a solution which exploits the catenary configuration assumed by tether and does not require any computationally demanding resource or complex cable tension sensors. Different approaches have been experimentally tested, compared and validated with classical localization systems in both indoor and outdoor environments.