Research On The CSI-based Inertial Localization System For UAV

With the increasing application of UAV,the research on the positioning system for UAV is becoming more and more popular.To guide the UAV in the process of application or to recycle it after the completion of tasks,the location information of the UAV need to be known.The cost of the GPS-based UAV positioning system is low and it can achieve ten meters level accuracy,but when in the non-line-of-sight environment,such as complex indoor environment,the areas covered by something,the city areas where there are skyscrapers closely lined,the GPS signals will be blocked and the location error will increase sharply.Therefore,this paper aims to explore a new technology which takes the advantage of Channel State Information(CSI)of WiFi channel frequency response,and combines the CSI acquisition data with the IMU data to achieve the real-time localization for the dynamic UAV.This study explores the feasibility of using the WiFi signal to achieve the UAV positioning,and provides the basis for the future research of the indoor UAV positioning system based on WiFi.To combine WiFi signal with IMU measurement technology to realize the UAV positioning,this paper has proposed the CSI-Based Inertial Localization System,named CILS.Firstly,the framework of CILS is presented,and the feature of CSI signals and Inertial measurement technology are introduced.Firstly,the framework of CILS is presented,the feature of CSI is introduced and the key technologies are analyzed.Then,a CSI-Based AOA algorithm is proposed to extract angle of arrival information by combining a small antenna array consisted of two omnidirectional antennas with CSI data provided by intel 5300 WiFi card.In order to realize the fusion of AOA information and IMU measurement data,the WiFi measurement model and the IMU measurement model will be analyzed to derive the measurement formula for CSI and IMU respectively.On the basis of the measurement formulas,the linear sliding window estimator is deduced to fuse these two kinds of data,and the optimal solution of the CILS system state vector can be solved by minimizing the sum of the Mahalanobis norm of these two measurement errors.From the optimal solution vector,the key information of the UAV are calculated,including the UAV's localization,so the aim of localizing the UAV is achieved.In order to prove the effectiveness of the CSI-IMU combination method,both the simulation and field experiments about CILS are performed in this paper.The results show that compared with the existing GPS-IMU inertial positioning system,the CSI-IMU inertial positioning system for UAV can realize the quite positioning accuracy without raising the computational complexity.Thus,the system stability has been significantly improved,and the average positioning accuracy of the CILS system can reach 1.6m.