无人机发展迅速,已经在地球科学领域得到了广泛应用.前人以中误差(root mean square error,RMSE)为精度评价指标对影响无人机摄影测量精度的各类因素进行了大量研究.但是,基于无人机摄影测量的地形建模误差往往空间上变化分布,中误差无...无人机发展迅速,已经在地球科学领域得到了广泛应用.前人以中误差(root mean square error,RMSE)为精度评价指标对影响无人机摄影测量精度的各类因素进行了大量研究.但是,基于无人机摄影测量的地形建模误差往往空间上变化分布,中误差无法反映误差的空间分布特征.因此,本文从误差空间分布的视角出发,通过计算误差空间分布图、误差的莫兰指数、样区整体的平均误差和标准误差,分析了相机倾角、航高和控制点数量对地形建模高程误差的大小及空间分布的影响.在黄土高原两个小流域的实验结果表明:(1)在无控制测量的情况下,误差受相机倾角的影响较大,采用较大角度的倾斜摄影不仅可以降低整体误差,还能改善误差的空间分布,减少误差的空间自相关性.(2)航高方面,尽管航高(60~160 m)变高会增大误差,但是航高对误差的空间分布影响不大.(3)在有控制测量的情况下,控制点的使用不仅降低了整体误差也优化了误差空间分布.在整体误差方面,使用少量的控制点即能达到一个稳定的精度水平.但此时,误差的空间分布还可以继续优化,要使样区的误差空间分布达到稳定的水平,需要相对较多的控制点.本研究为使用消费级无人机进行地形建模提供了有益的参考,在实际应用中可根据本文的结论优化航线设计方案和控制点布设.展开更多
In order to reduce the accident rate of consumer-grade unmanned aerial vehicles(UAVs)in daily use scenarios,the accident causes are analyzed based on the accident cases of consumer-grade UAVs.By extracting accident ca...In order to reduce the accident rate of consumer-grade unmanned aerial vehicles(UAVs)in daily use scenarios,the accident causes are analyzed based on the accident cases of consumer-grade UAVs.By extracting accident causing factors based on the Grounded theory,the relationship between these factors is analyzed.The Bayesian network for consumer-grade UAV accidents is constructed.With the Grounded theory-Bayesian network,the probability of four types of accidents is inferred:fall,air collision,disappearance,and personal injury.With the posterior probability of each factor being reversely reasoned,the causal chain with the maximum probability of each accident is obtained.After the sensitivity of each factor is analyzed,the key nodes in the network accordingly are inferred.Then the causing factors of consumer-grade UAV accidents are analyzed.The results show that the probability of fall accident is the highest,the fall accident is associated with the probabilistic maximum causal chain of personal injury,and the sensitivity analysis results of each type of accident as the result node are inconsistent.展开更多
文摘无人机发展迅速,已经在地球科学领域得到了广泛应用.前人以中误差(root mean square error,RMSE)为精度评价指标对影响无人机摄影测量精度的各类因素进行了大量研究.但是,基于无人机摄影测量的地形建模误差往往空间上变化分布,中误差无法反映误差的空间分布特征.因此,本文从误差空间分布的视角出发,通过计算误差空间分布图、误差的莫兰指数、样区整体的平均误差和标准误差,分析了相机倾角、航高和控制点数量对地形建模高程误差的大小及空间分布的影响.在黄土高原两个小流域的实验结果表明:(1)在无控制测量的情况下,误差受相机倾角的影响较大,采用较大角度的倾斜摄影不仅可以降低整体误差,还能改善误差的空间分布,减少误差的空间自相关性.(2)航高方面,尽管航高(60~160 m)变高会增大误差,但是航高对误差的空间分布影响不大.(3)在有控制测量的情况下,控制点的使用不仅降低了整体误差也优化了误差空间分布.在整体误差方面,使用少量的控制点即能达到一个稳定的精度水平.但此时,误差的空间分布还可以继续优化,要使样区的误差空间分布达到稳定的水平,需要相对较多的控制点.本研究为使用消费级无人机进行地形建模提供了有益的参考,在实际应用中可根据本文的结论优化航线设计方案和控制点布设.
基金supported by the Fun⁃damental Research Funds for the Central Universities(No.3122022103).
文摘In order to reduce the accident rate of consumer-grade unmanned aerial vehicles(UAVs)in daily use scenarios,the accident causes are analyzed based on the accident cases of consumer-grade UAVs.By extracting accident causing factors based on the Grounded theory,the relationship between these factors is analyzed.The Bayesian network for consumer-grade UAV accidents is constructed.With the Grounded theory-Bayesian network,the probability of four types of accidents is inferred:fall,air collision,disappearance,and personal injury.With the posterior probability of each factor being reversely reasoned,the causal chain with the maximum probability of each accident is obtained.After the sensitivity of each factor is analyzed,the key nodes in the network accordingly are inferred.Then the causing factors of consumer-grade UAV accidents are analyzed.The results show that the probability of fall accident is the highest,the fall accident is associated with the probabilistic maximum causal chain of personal injury,and the sensitivity analysis results of each type of accident as the result node are inconsistent.
