A Centerless Network-Enable Cooperative Relative Positioning Method for Multi-drones in Non-GNSS Area

Multi-drones’ cooperative tasks highly rely on continuous and accurate relative positioning, while the positioning methods rely on traditional commercial satellite navigation technology has growing potential risks, and a substitute positioning method in non-GNSS area is highly needed. A cooperative relative method by flight ad-hoc is putted forward: all drones forming a centerless network, ranging with each other by integrated signal and three-way method, then each drone could calculate the relative positioning by a rigid frame algorithm and achieve 3 × n relative position matrix result, if the drones’ links meet the spatial rigidity conditions. In order to verify the feasibility of the network enable cooperative positioning method, an airborne prototype installed on drones and a flight test & evaluation system are developed, through outdoor static test and indoor flight test, the measured data show that the method could achieved continuous positioning results with sub-meter precision without using GNSS receiver or wireless anchors: the minimum and maximum 3-D relative positioning error of 5 prototypes flying in similar height are 0.2 m (75%) and 0.8 m (75%).