Sensor Fusion-based Indoor Multi-hop Localization For UAV Swarm

Over the last decade,UAV technology has been continuously improved and widely applied in various fields.In order to improve the efficiency of UAVs,the related technology of using UAV swarm to replace a single UAV is concerned.A typical application of UAV swarm technology is to take inventory of goods in a large warehouse.In order to perform tasks safely and efficiently,it is necessary to localize the UAVs in the swarm precisely.Conventional computer vision-based solutions only work in well-lighted and texture-rich environments.Wireless signal-based solutions are only suitable for small indoor environments.While the indoor area becomes larger,many anchor nodes are needed,which results in a sharp increase in cost.In response to the above problems,we propose a sensor fusion-based indoor multi-hop localization solution for UAV swarm,using ultra-wideband(UWB)signals,inertial measurement units(IMU)and ultrasonic sensors to achieve indoor localization of UAV swarm.Compared with other solutions,this solution has no requirements for lighting and environmental texture;and only a few UWB anchor nodes need to be pre-arranged to enable high-precision localization of UAV swarm in large indoor spaces.In this solution,multi-hop localization can use the UAVs as virtual anchor nodes to expand the localization coverage,which makes the UAVs far away from the anchor nodes can also be localized precisely.By carefully designing the multi-hop communication protocol between the anchor nodes and the UAVs,the entire localization system can still ensure a high real-time performance when facing a large UAV swarm.Sensor fusion algorithm can fuse UWB measurement information,IMU measurement information and ultrasonic ranging information,which makes the localization result better than those using only UWB measurement information.In addition,sensor fusion algorithm can improve the localization stability of the UAVs when the UWB measurement information is insufficient.Simulation results show that in a large indoor environment with a size of 1008)× 1008)× 88),this solution only needs to prearrange 5 UWB anchor nodes to meet the localization requirements of UAVs.For UAVs near the UWB anchor nodes,97% of the localization errors are within 0.2 meters.For UAVs far away from the UWB anchor nodes,91% of the localization errors are within 0.2 meters when get enough ranging information.