Research On Unmanned Aerial Vehicle Indoor Positioning Technology With Ultra Wide Band Fusion Optical Flow

In recent years,with the rapid development of unmanned aerial vehicle related technology,its application field has been widened.It has expanded from the early military field to the civil field,from outdoor application to indoor application.In recent years,indoor unmanned aerial vehicle is slowly emerging,such as catering,warehousing,office and other industries.It is expected that there will be more room for application in the future,Compared with open outdoor environment,the indoor environment is narrow and complex,so in order to make the unmanned aerial vehicle better used in the indoor environment,it needs more precise positioning technology support.And the mature outdoor global positioning system,because of the building block barrier makes the satellite signal fast attenuation,even completely refuses,it can not meet the needs of the indoor scene positioning.At the same time,because of the complexity of the unmanned aerial vehicle,the existing indoor positioning technology is difficult to better apply to the unmanned aerial vehicle positioning.Therefore,the research of the unmanned aerial vehicle indoor positioning technology has become a hot spot of common concern in the industry and the academia.In recent years,although there are a small number of achievements on the research of unmanned aerial vehicle indoor positioning technology,most of them are limited to the theoretical level,and it is rarely reported to be actually put into practice.Therefore,it is of great practical significance to explore and study the indoor positioning technology of unmanned aerial vehicle with high practicability and high positioning accuracy.In order to further improve the positioning accuracy of unmanned aerial vehicle in the indoor scene,this paper proposes a new type of Ultra Wide Band(UWB)indoor positioning technology and the machine vision based optical flow positioning technology,which combines the advantages of the them and uses the federal Kalman filter to locate and fuse the new unmanned aerial vehicle indoor location method.Among them,UWB positioning adopts the method of circumferential positioning based on arrival time,The centimeter level positioning of unmanned aerial vehicle in sight distance is realized.At the same time,considering that when the UWB signal propagates in the non line of sight condition,it will bring greater non line of sight error to the positioning result.A high-precision optical flow localization algorithm with pose compensation is introduced to match the UWB location algorithm.In order to maximize the advantages of the two positioning methods,we further enhance the performance of the localization algorithm.The federal Kalman filtering algorithm with two sub Kalman filters is introduced to achieve the efficient and organic filtering fusion of the two location algorithms of optical flow localization and UWB positioning.Based on the non sight distance identification based on cross area,the non sight distance is identified.According to the non sight distance identification results,the dynamic adaptive adjustment of the information distribution coefficient of the federal Kalman filter and the measurement error covariance matrix of the UWB Kalman filter in the federated Kalman filter positioning fusion algorithm.To ensure that the result of fusion positioning is biased towards a more accurate positioning method.In addition,because the optical flow positioning is the same as the inertial navigation position,so with the increase of positioning distance,the positioning error will continue to accumulate.For this reason,we use the federated filter to localize the fusion results to compensate the optical flow location periodically,and constantly correct the optical flow localization results,so as to ensure the positioning accuracy.The algorithm does not increase the time of calculation too much,And the high accuracy positioning of indoor unmanned aerial vehicle is realized.In order to verify the feasibility and practicability of the unmanned aerial vehicle positioning and optical flow localization method for unmanned aerial vehicle indoor positioning,In this paper,the UWB positioning system is built in the laboratory environment,and the four rotor unmanned aerial vehicle platform with a optical flow sensor is used to carry out the indoor positioning experiment.The real-time rendering of the unmanned aerial vehicle flight path and the record of the positioning result are realized by the upper computer.The analysis of the experimental results shows that this method can solve the non sight distance problem well in UWB positioning,and give full play to the advantages of UWB positioning and optical flow positioning.On the basis of ensuring real-time positioning,the positioning accuracy of indoor unmanned aerial vehicle is further improved.The positioning results show that this method can meet the requirements of unmanned aerial vehicle in general indoor scene.