Research On GNSS/UWB Air-ground Collaborative High-precision Positioning Model And Method In Sheltered Areas

With the high-quality transformation and development of society,ecology,and economy,accelerating the process of rural intellectualization,digitization,and networking is becoming increasingly important for China to build a smart village and complete the rural revitalization strategy.However,the rapid and high-precision positioning of villages and towns in complex environments and weak GNSS environments such as sheltered areas still lacks key practical intelligent technologies and equipment,and there are shortcomings in positioning models and methods.Therefore,this article focuses on the topic of rapid and high-precision positioning of sheltered areas,and conducts research on air-ground collaborative positioning models and methods based on unmanned aerial vehicles,GNSS,UWB,and other technologies in sheltered areas.The content includes UWB ranging error optimization model,GNSS/UWB air-ground collaborative positioning method,air-ground collaborative positioning network geometry optimization,and GNSS/UWB positioning model.The following main innovative achievements have been achieved:(1)The UWB ranging and positioning technology is described.Aiming at the problem of UWB ranging error in the air-ground cooperative positioning system in the sheltered area,the source of UWB ranging error is analyzed.An error correction model for the ranging system is established based on a polynomial fitting function,and a range gross error detection and repair model is established based on an improved range filtering KF.Through these two models,the UWB air-ground ranging error is optimized and compensated,the experiment proves that the average ranging accuracy of the 70 meter ranging distance optimized by the model has been significantly improved,indicating that it can effectively weaken the ranging error,effectively reducing ranging errors.Finally,a simulation experiment is designed to analyze the impact of ranging error,number of base stations,and network configuration of base stations on location performance.(2)Aiming at the need for rapid air-ground collaborative positioning in sheltered areas,a single machine multi-point collaborative positioning method was proposed.Through the UAV carrying GNSS/UWB and cooperating with ground targets,the sheltered area positioning measurement was completed in the manner of single machine flying around and multi-point network ranging.In addition,a "meter" shaped air-ground collaborative positioning method was designed for areas with very severe sheltering.After experimental testing,the method can effectively achieve sheltered area positioning,Improves the efficiency of masking area positioning.(3)In response to the problem of unsatisfactory positioning of base stations caused by obstruction of buildings(structures),trees,and other structures in sheltered areas,the drone status and spatial network structure in sheltered scenes are studied.Based on the motion state model of aerial drones,a 1-minute time sliding window technology is proposed to interpret the drone position information and motion status,screen out the observation information during the hovering measurement period,and optimize and compensate the observation data.Based on the positioning accuracy factor,a GDOP value model and a DOP value minimization criterion were established.Two unmanned aerial vehicle deployment methods,geometric optimization deployment and optimal combination deployment,were proposed.A fast and efficient unmanned aerial vehicle observation station deployment principle was determined,and in order to ensure measurement efficiency,the number of observation points was minimized as much as possible while meeting the DOP value requirements.The number of observation stations did not exceed 9.Simulation and actual measurement experiments showed that:,The square and Yshaped regular geometric configurations have high positioning accuracy.(4)In response to the challenges of high-precision,high-efficiency,and high reliability positioning in complex environments in shaded areas,based on the principle of spatial distance resection,considering the variance component of ranging error and drone position error,an LSGN hybrid positioning model and a robust KF positioning model for abnormal observation information were constructed.The RKF model has better robustness than LS,achieving centimeter level positioning accuracy in shaded areas.Based on the above research results,an air ground collaborative positioning and calculation system integrating control,ranging,positioning,calculation,and communication has been formed.This paper selects multiple scenarios in the sheltered area to conduct validation experiments and analysis.In the face of complex environments,houses,trees,and other obstructed environments,rapid and reliable positioning measurement of target points in the sheltered area has been achieved,with positioning accuracy reaching centimeter level,This fully verifies the efficiency and reliability of the air ground collaborative positioning model and method proposed in this article..