UWB And Optical Flow Assisted Positioning For Four-rotor UAV Indoor Navigation

With the development of science and technology,the application of small multi-rotor unmanned aerial vehicles(UAV)is becoming more and more extensive and more intelligent.But in the absence of GPS signal environment,UAV can not know its own location,which can not be positioned and navigation flight,making its intelligence greatly limited.In recent years,many scientific research institutions and experts put forward a variety of unmanned indoor navigation program.With the background of UAV indoor navigation flight,this paper puts forward the method of four-rotor unmanned aerial vehicle indoor navigation based on ultra-wideband positioning and optical flow assisted positioning.Compared with other indoor navigation schemes,there are advantages that the positioning area is not restricted,the positioning accuracy is high and the cost is low.The main contents of this paper include:First of all,this paper presents the structure and frame of the whole indoor positioning system,and clarifies the system composition.The flight principle of the four-rotor UAV and the coordinate system defined are emphatically introduced of this paper.Secondly,design the system hardware platform,divided into UAV flight control circuit board,remote control circuit board and ultra-wideband communication base station circuit board.Among them,in order to enhance the safety of UAV indoor flight process,I design the dual controller and dual inertial navigation sensor's hardware architecture on the flying control circuit board,which greatly enhance the UAV flight's anti-jamming capability and security.Again,the software algorithm in the UAV system is realized.In this paper,we use the quaternion attitude algorithm to calculate the euler angle of UAV,which have the advantages of small computation.In view of the interference caused by the vibration of the four-rotor UAV during flight,the extended Kalman filter is designed to filter the sensor data,and the whole process was deduced.Taking into the project implementation and unmanned aerial vehicle control needs,multi-level serial PID controller is designed for UAV location and attitude control.Then,the general method of UWB communication is introduced,and an ultrawideband multi-base station fusion location algorithm is proposed to improve the positioning accuracy.In order to solve the shortcomings of low sampling frequency,low dynamic response and high frequency noise in UWB communication,this paper designs the location data of ultra wideband communication and optical flow sensor to fuse the filter.So that we can obtain the dynamic response more quickly and positioning data with lower high-frequency noise to enhance the positioning of the accuracy and dynamic response characteristics.Finally,the four-rotor unmanned aerial vehicle indoor flight and indoor navigation flight test were carried out.The experimental results show that the four-rotor UAV indoor positioning and navigation flight system is reasonable and effective.