Grid A*:A fast path planning algorithm for air-ground cooperative response of emergency rescue in the field
Disasters and accidents often occur in remote areas that are inaccessible by conventional transportation.Common map navigation software also fails to provide a passable path.Therefore,only Sport Utility Vehicles(SUVs)can be used in field rescues.However,ground vehicles have limited awareness of their surroundings,so we chose to set up an air-ground cooperative system to overcome these vehicles'shortcoming.In the air-ground cooperative system,Unmanned Aerial Vehicles(UAVs)can provide environmental images surrounding the SUV for the ground terminal to obtain the navigation path of the vehicle by quickly extracting the type of surface and terrain undulations in the images.To better meet the above application requirement,this paper improves the existing A*algorithm with three main innovations.First,we proposed a passability cost function that integrates surface type and surface elevation information considering the application characteristics of the outdoor surface environment.Second,we proposed a fast path search algorithm based on grid cells given the scale relationship between the resolution of UAV images and the actual vehicle paths.Third,we chose the marginal feature points of the grid for the passability path search in view of the connected surface-type distribution inside the grid cell.This approach improves the search efficiency of the algorithm while taking into account the terrain information inside the grid cell,such that the algorithm could make full use of the detailed information of the UAV images and optimize the calculation.The 3D visualization experiments show that the paths searched by the Grid A*algorithm are more reliable and meet the needs of SUVs.The Grid A*algorithm proposed in this paper,aiming at the high-resolution images obtained by UAV,synthesizes image classification,slope calculation,and other methods to structure a passability cost function so that the paths are more reliable.In addition,the time cost of the algorithm is reduced to 15％of the traditional A*algorithm,which improves the timeliness of emergency rescue in the field.
remote sensingpath planningGrid A*algorithmA*algorithmair-ground coordinationpassability cost function
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