To address the issue of premature convergence and slow convergence rate in three-dimensional (3D) route planning of unmanned aerial vehicle (UAV) low-altitude penetration,a novel route planning method was proposed.Fir...To address the issue of premature convergence and slow convergence rate in three-dimensional (3D) route planning of unmanned aerial vehicle (UAV) low-altitude penetration,a novel route planning method was proposed.First and foremost,a coevolutionary multi-agent genetic algorithm (CE-MAGA) was formed by introducing coevolutionary mechanism to multi-agent genetic algorithm (MAGA),an efficient global optimization algorithm.A dynamic route representation form was also adopted to improve the flight route accuracy.Moreover,an efficient constraint handling method was used to simplify the treatment of multi-constraint and reduce the time-cost of planning computation.Simulation and corresponding analysis show that the planning results of CE-MAGA have better performance on terrain following,terrain avoidance,threat avoidance (TF/TA2) and lower route costs than other existing algorithms.In addition,feasible flight routes can be acquired within 2 s,and the convergence rate of the whole evolutionary process is very fast.展开更多
[ Objective ] The paper was to study the occurrence and damage regularity of tobacco cutworm moth （Spodoptera Litura Fabricius） in low-altitude area in Lincang city. [ Method] The adult sex attractant monitoring, fi...[ Objective ] The paper was to study the occurrence and damage regularity of tobacco cutworm moth （Spodoptera Litura Fabricius） in low-altitude area in Lincang city. [ Method] The adult sex attractant monitoring, field investigation of occurrence and damage, and observation of continuous generation development of natural populations were carried out in natural flue-cured tobacco fields. [ Result] In field growth period of flue-cured tobacco under low-altitude of 1 000 - 1300 m, tobacco cutworm moth occurred for 4 generations, the duration of each generation was about 33 d, and the main injurious generation was the third generation. [ Conclusion] The paper provided reference for comprehensive control of tobacco cutworm moth in the low altitude areas.展开更多
Atmospheric inversion phenomenon directly affects the vertical movement of air, which causes the cooling heat of the cooling tower in the power plant to be blocked. Therefore, it is necessary to analyze the atmospheri...Atmospheric inversion phenomenon directly affects the vertical movement of air, which causes the cooling heat of the cooling tower in the power plant to be blocked. Therefore, it is necessary to analyze the atmospheric inversion characteristics of the research project during the design of the air cooling system. Using the low-altitude observing system of the tethered balloon, the on-site observation of the temperature below 300 m in summer is carried out for a coal-fired power integration project in Yulin, Shaanxi, China. Observations were made at 10 fixed times per day, with a cumulative observation of 46 days and 247 effective detections. The data were quality-controlled, and then linearly interpolated. According to the requirements of the project designer, the temperature data of 20, 50, 100, 150, 200, 250, 300 m was used for low-temperature inversion analysis. The research shows that the grounding inversion and low-altitude inversion can be observed at the same time. In the time and space changes, the grounding inversion temperature and intensity are significantly higher than the low-altitude inversion. The maximum inversion of grounding inversion and low-altitude inversion is 2.3?C/hm, 1.0?C/hm. Grounding inversion temperature occurs every time, the frequency is the highest at 20 o’clock, the average intensity is maximum at 17 o’clock, and the average height, maximum intensity and maximum height are maximum at 7 o’clock. When the low-altitude inversion temperature is 18 o’clock, other times can occur, and the frequency is the highest at 15 o’clock, but the inversion layer is shallow, the bottom is high and the intensity is small. Grounding inversion and low-altitude inversion can occur in all levels, and as the height increases, the grounding inversion decreases and the low-temperature inversion increases. The design of the project air cooling tower needs to fully consider the impact caused by the inverse temperature below 300 m.展开更多
Infrared windshear prediction is one of airborne LLWS remote sensing methods.Before it is applied,the prediction system should be tested on ground to prove it’s feasibility.The LLWS simulation system isused to check ...Infrared windshear prediction is one of airborne LLWS remote sensing methods.Before it is applied,the prediction system should be tested on ground to prove it’s feasibility.The LLWS simulation system isused to check whether the infrared windshear prediction system operate properly.In this paper,according tothe requirement of the LLWS detection and the characteristic of LLWS＂source＂,we will analyze the theoryof the LLWS simulation and give a basic description of the system construction in which we pay more atten-tion to optical simulation and flight simulation.The optical simulation is used to simulate the atmospherc in-frared radiation as a LLWS occurs.The flight simulation is used to simulate the aircraft airspeed,pitch,alti-tude etc..The works presented here are necessary for the LLWS infrared prediction system.展开更多
为识别复杂地形影响下香港国际机场(HKIA,Hong Kong International Airport)低空风切变的易发空域,采用大涡模拟方法(LES,large eddy simulation)对机场及其周边地形进行了风场精细化数值模拟。结合风速云图比较东、东南、南、西南风背...为识别复杂地形影响下香港国际机场(HKIA,Hong Kong International Airport)低空风切变的易发空域,采用大涡模拟方法(LES,large eddy simulation)对机场及其周边地形进行了风场精细化数值模拟。结合风速云图比较东、东南、南、西南风背景下3条跑道起降航道上的风速变化,分析得出了地形与风场分布间的因果关系。通过与无地形情况下的对照试验结果对比,采用F因子(识别逆风)和7节标准(识别侧风)识别机场跑道低空风切变易发区间。结果表明,东风易造成飞机进离场的逆风风速发生时空变化;西南风影响跑道东侧着陆路径上的逆风风速,但几乎不影响跑道西侧离场路径的风速;在东南风和南风背景下,3条跑道起降航道低空段的侧风均受地形影响显著。根据3条跑道进离场航道上的低空风切变易发空域,得到了地形因素对香港国际机场低空风切变的影响范围,研究结果可为机场风切变风险防控提供主动规避措施和建议。展开更多
The concepts of “digital twins”, “3D real scene”, “metacosm” and others were the technical paths for building digital cities with the development of emerging surveying and mapping science and technology, which w...The concepts of “digital twins”, “3D real scene”, “metacosm” and others were the technical paths for building digital cities with the development of emerging surveying and mapping science and technology, which was to build a digital and virtualized city that matched the real physical world, to achieve a one-to-one correspondence between all elements of the physical world and the digital virtual world. And one of its basic geographic information data was a highly similar, virtual simulation of the 3D real scene. After exploring the traditional manual 3DsMax modeling, UAV low-altitude digital oblique photogrammetry modeling, airborne laser scanning modeling and other single modeling technologies, this paper discussed the 3D digital modeling technology used by the UAV airborne laser scanning point cloud and low-altitude digital oblique photogrammetry for complementary integration, constructing the 3D scene of the digital city. This paper expounded the technical route and production process of 3D digital modeling, in order to provide technical references for related projects.展开更多
基金Project(60925011) supported by the National Natural Science Foundation for Distinguished Young Scholars of ChinaProject(9140A06040510BQXXXX) supported by Advanced Research Foundation of General Armament Department,China
文摘To address the issue of premature convergence and slow convergence rate in three-dimensional (3D) route planning of unmanned aerial vehicle (UAV) low-altitude penetration,a novel route planning method was proposed.First and foremost,a coevolutionary multi-agent genetic algorithm (CE-MAGA) was formed by introducing coevolutionary mechanism to multi-agent genetic algorithm (MAGA),an efficient global optimization algorithm.A dynamic route representation form was also adopted to improve the flight route accuracy.Moreover,an efficient constraint handling method was used to simplify the treatment of multi-constraint and reduce the time-cost of planning computation.Simulation and corresponding analysis show that the planning results of CE-MAGA have better performance on terrain following,terrain avoidance,threat avoidance (TF/TA2) and lower route costs than other existing algorithms.In addition,feasible flight routes can be acquired within 2 s,and the convergence rate of the whole evolutionary process is very fast.
基金Supported by Project of China National Tobacco Corporation Yunnan Branch( 2010YN77)
文摘[ Objective ] The paper was to study the occurrence and damage regularity of tobacco cutworm moth （Spodoptera Litura Fabricius） in low-altitude area in Lincang city. [ Method] The adult sex attractant monitoring, field investigation of occurrence and damage, and observation of continuous generation development of natural populations were carried out in natural flue-cured tobacco fields. [ Result] In field growth period of flue-cured tobacco under low-altitude of 1 000 - 1300 m, tobacco cutworm moth occurred for 4 generations, the duration of each generation was about 33 d, and the main injurious generation was the third generation. [ Conclusion] The paper provided reference for comprehensive control of tobacco cutworm moth in the low altitude areas.
文摘Atmospheric inversion phenomenon directly affects the vertical movement of air, which causes the cooling heat of the cooling tower in the power plant to be blocked. Therefore, it is necessary to analyze the atmospheric inversion characteristics of the research project during the design of the air cooling system. Using the low-altitude observing system of the tethered balloon, the on-site observation of the temperature below 300 m in summer is carried out for a coal-fired power integration project in Yulin, Shaanxi, China. Observations were made at 10 fixed times per day, with a cumulative observation of 46 days and 247 effective detections. The data were quality-controlled, and then linearly interpolated. According to the requirements of the project designer, the temperature data of 20, 50, 100, 150, 200, 250, 300 m was used for low-temperature inversion analysis. The research shows that the grounding inversion and low-altitude inversion can be observed at the same time. In the time and space changes, the grounding inversion temperature and intensity are significantly higher than the low-altitude inversion. The maximum inversion of grounding inversion and low-altitude inversion is 2.3?C/hm, 1.0?C/hm. Grounding inversion temperature occurs every time, the frequency is the highest at 20 o’clock, the average intensity is maximum at 17 o’clock, and the average height, maximum intensity and maximum height are maximum at 7 o’clock. When the low-altitude inversion temperature is 18 o’clock, other times can occur, and the frequency is the highest at 15 o’clock, but the inversion layer is shallow, the bottom is high and the intensity is small. Grounding inversion and low-altitude inversion can occur in all levels, and as the height increases, the grounding inversion decreases and the low-temperature inversion increases. The design of the project air cooling tower needs to fully consider the impact caused by the inverse temperature below 300 m.
文摘Infrared windshear prediction is one of airborne LLWS remote sensing methods.Before it is applied,the prediction system should be tested on ground to prove it’s feasibility.The LLWS simulation system isused to check whether the infrared windshear prediction system operate properly.In this paper,according tothe requirement of the LLWS detection and the characteristic of LLWS＂source＂,we will analyze the theoryof the LLWS simulation and give a basic description of the system construction in which we pay more atten-tion to optical simulation and flight simulation.The optical simulation is used to simulate the atmospherc in-frared radiation as a LLWS occurs.The flight simulation is used to simulate the aircraft airspeed,pitch,alti-tude etc..The works presented here are necessary for the LLWS infrared prediction system.
文摘为识别复杂地形影响下香港国际机场(HKIA,Hong Kong International Airport)低空风切变的易发空域,采用大涡模拟方法(LES,large eddy simulation)对机场及其周边地形进行了风场精细化数值模拟。结合风速云图比较东、东南、南、西南风背景下3条跑道起降航道上的风速变化,分析得出了地形与风场分布间的因果关系。通过与无地形情况下的对照试验结果对比,采用F因子(识别逆风)和7节标准(识别侧风)识别机场跑道低空风切变易发区间。结果表明,东风易造成飞机进离场的逆风风速发生时空变化;西南风影响跑道东侧着陆路径上的逆风风速,但几乎不影响跑道西侧离场路径的风速;在东南风和南风背景下,3条跑道起降航道低空段的侧风均受地形影响显著。根据3条跑道进离场航道上的低空风切变易发空域,得到了地形因素对香港国际机场低空风切变的影响范围,研究结果可为机场风切变风险防控提供主动规避措施和建议。
文摘The concepts of “digital twins”, “3D real scene”, “metacosm” and others were the technical paths for building digital cities with the development of emerging surveying and mapping science and technology, which was to build a digital and virtualized city that matched the real physical world, to achieve a one-to-one correspondence between all elements of the physical world and the digital virtual world. And one of its basic geographic information data was a highly similar, virtual simulation of the 3D real scene. After exploring the traditional manual 3DsMax modeling, UAV low-altitude digital oblique photogrammetry modeling, airborne laser scanning modeling and other single modeling technologies, this paper discussed the 3D digital modeling technology used by the UAV airborne laser scanning point cloud and low-altitude digital oblique photogrammetry for complementary integration, constructing the 3D scene of the digital city. This paper expounded the technical route and production process of 3D digital modeling, in order to provide technical references for related projects.
