Research On Unmanned Aerial Vehicle Flight Trajectory Measurement Method Based On Ultra Wideband And Inertial Navigation Fusion

In recent years,with the rapid development of civil unmanned aerial vehicle industry in China,its application is becoming more and more extensive.It is urgent to construct the evaluation method and system of unmanned aerial vehicle flight performance.Flight trajectory detection is an important aspect of unmanned aerial vehicle flight performance evaluation.Unmanned aerial vehicle flight path detection has the requirements of large-scale,dynamic and real-time measurement.Light and small unmanned aerial vehicle puts forward the requirements of small volume and light weight for the detection load.In this paper,taking advantage of the characteristics of ultra wideband high precision,light load and good dynamic performance of inertial navigation,a flight trajectory measurement method based on the fusion of ultra wideband and inertial navigation is proposed.The research is carried out from the aspects of ultra wideband trajectory point positioning method,inertial navigation motion and error model,fusion filter state and observation model,The flight trajectory measurement system of unmanned aerial vehicle based on the fusion of ultra wideband and inertial navigation is developed,and the experimental verification is completed.The main work of this paper is as follows:1.This paper analyzes the measurement requirements and common trajectory measurement methods of unmanned aerial vehicle flight trajectory measurement with high precision,high dynamic performance,large range and light load,and designs a flight trajectory measurement scheme based on the integration of ultra wideband and inertial navigation.The unmanned aerial vehicle mounts the ultra wideband tag and inertial navigation sensor,and uses ultra wideband to realize the high-precision measurement of trajectory coordinate refresh rate of 10 sps,then the light load inertial navigation and ultra wideband are combined to realize the trajectory coordinate100 sps interpolation,and the inertial navigation measurement error is corrected by filtering to complete the high-precision dynamic trajectory measurement.2.A unmanned aerial vehicle tag coordinate solution method based on iteration and weighted least squares is proposed.According to the characteristics of redundant base stations,an ultra wideband high-precision coordinate solution model based on signal arrival time difference is established.Through equation simplification and derivation,the initial value iterative solution of tag three-dimensional coordinates is directly realized by two-step weighted least squares,Then,the accurate solution of coordinates is realized by Taylor method.The simulation shows that adding the second step least square iteration can improve the accuracy of initial value solution.The source of ultra wideband measurement error is analyzed and the error model is established.The experimental results show that the proposed method has similar measurement accuracy and simpler steps compared with Chan + Taylor method,which proves the effectiveness of the proposed method.3.The flight trajectory measurement model of unmanned aerial vehicle based on the fusion of ultra wideband and inertial navigation is established.The inertial navigation error is used as the state quantity,and the measurement information of ultra wideband pseudo range,single position,position combined speed and arrival time difference are used as the observation measurement respectively.The inertial navigation error is estimated and compensated by Kalman filter.Finally,the compensated inertial navigation data is used to interpolate the ultra wideband measurement coordinates,and the fusion measurement of flight trajectory is realized.4.The unmanned aerial vehicle flight trajectory measurement system is developed and the trajectory measurement experiment is carried out.The results show that the position refresh rate of the method proposed in this paper reaches 100 sps,the horizontal error of trajectory coordinate measurement is less than 0.1m,and the elevation error is less than 0.15 m in 120m×60m×40m test site,which can meet the index requirements of unmanned aerial vehicle flight trajectory measurement system.