Design And Implementation Of Indoor Nano-quadcopter Formation Flight System Based On UWB Positioning Technology

In recent years,the four-rotor unmanned aerial vehicles(UAVs)have been widely used in military and civilian fields due to their hovering,flexible movement and high stability.On the basis of the single UAV,the formation of multiple UAVs can be used for more complicated work.Hence,the UAV formation technology is the development trend and research hotspot of UAV technology in recent years.At present,the navigation of UAVs mainly relies on GPS outdoors.However,the UAVs are unable to correctly estimate its position indoors because the GPS singals are too weak to support autonomous flight.Based on the background of indoor UAV formation flight,this paper proposes an indoor positioning and navigation system based on the ultra-wideband indoor positioning technology and inertial navigation track derivation algorithm.The main work is concluded below:Firstly,this paper deeply investigates the research status of domestic and foreign UAV formation technology and indoor positioning technology,and proposes a positioning and communication scheme suitable for indoor UAV formation flight.The system is mainly composed of UWB three-dimensional positioning subsystem,nano-quadcopter subsystem,navigation subsystem and coordinator.Secondly,this paper designs an improved TDOA positioning algorithm based on time division,which can be applied to the scenarios of multiple positioning targets.Aiming at the problem that the extreme value point is easy to appear when the UWB positioning technology is used alone,the EKF algorithm is used to fuse the UWB positioning algorithm with the inertial navigation track derivation algorithm to improve the accuracy and stability of the positioning system.Finally,the software and hardware design and implementation of the system are completed,and the indoor positioning performance test and indoor navigation flight test were carried out.The test results show that the UWB three-dimensional positioning system has a positioning accuracy of±10 cm with high precision,multi-label,high real-time and anti-occlusion which can meet the requirements of UAV formation flight indoors.Therefore,the indoor positioning and navigation system of UAV formation designed in this paper is feasible.