Search Pattern Generation and Path Management for Search over Rough Terrain with a Small UAV
Search operations can be described by the interaction between three entities: the target, the sensor, and the environment. Past treatments of the search problem have focused primarily on the interaction between the sensor and the target. The effects that the environment has on the target and sensor...
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| Format: | Others |
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BYU ScholarsArchive
2010
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| Online Access: | https://scholarsarchive.byu.edu/etd/2275 https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3274&context=etd |
| Summary: | Search operations can be described by the interaction between three entities: the target, the sensor, and the environment. Past treatments of the search problem have focused primarily on the interaction between the sensor and the target. The effects that the environment has on the target and sensor have been greatly simplified or ignored completely. The wilderness search and rescue scenario is one case in which these interactions cannot be safely ignored. Using the wilderness search and rescue problem as our motivating example, we develop an algorithm for planning search paths for a small unmanned aerial vehicle (UAV) over rough terrain environments that provide complete coverage of the specified terrain region while minimizing effort wasted on duplicate coverage. The major components of this algorithm include 1) breaking the search region into smaller sub-regions that are easier to deal with, and 2) planning the search for each of these sub-regions. The original contributions of this thesis focus on the latter of these two components. We use a method based on the directional offset of terrain contours to produce paths on the terrain for the sensor to observe as the UAV follows the flight path. We then employ directional-offset methods again by moving in the direction along the terrain normal from the sensor path to generate a flight path that lies in the air a specified distance away from the points on the terrain that are to be observed. These two paths are linked in a way that provides the sensor with an ample viewing opportunity of the terrain regions below. We implement this planning algorithm in software with Matlab, and provide a complete simulation of a UAV that follows the planned search pattern. Our planning algorithm produced search paths that were 94 to 100 percent complete in test scenarios for several rough-terrain regions. Missed regions for these plans were near the search boundaries, and coverage could easily be provided by subsequent plans. We recommend the study of region segmentation, with careful consideration of planning algorithms as the major focus of future work. |
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