Adaptive Cooperative Navigation Strategies for Complex Environments

Multi-UAV Cooperation is a promising strategy to enhance navigation performance. In this framework, a UAV, termed chief, can exploit cooperative vehicles, deemed deputies, who share positioning information and enable relative measurements by ranging and/or bearing sensors, to improve its state estimation accuracy. Different cooperative strategies are available depending on the status of the formation. Specifically, based on the GNSS coverage conditions, cooperative aiding can be used to support position and/or attitude estimation. This paper introduces an adaptive navigation filter that automatically selects the relevant strategy to be used in each phase of flight. In addition, within a multi-UAV scenario, the effect of simultaneous exploitation of different cooperative navigation strategies onboard different UAVs is investigated. The adaptive filter is tested both on simulated and experimental flight data, showing the benefit of adaptively using shared data within the cooperative multi-vehicle system.