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Accuracy assessment of real-time kinematics(RTK)measurements on unmanned aerial vehicles(UAV)for direct geo-referencing

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Geo-Spatial Information Science 2020年第2期23卷 165-181页

作者： Desta Ekaso Francesco Nex Norman Kerle Department of Earth Systems Analysis ITC-Faculty of Geo-Information Science and Earth Observation of the University of TwenteEnschedeThe NetherlandsDepartment of Earth Systems AnalysisITC-Faculty of Geo-Information Science and Earth Observation of the University of TwenteEnschedeThe NetherlandsDepartment of Earth Systems AnalysisITC-Faculty of Geo-Information Science and Earth Observation of the University of TwenteEnschedeThe Netherlands

Geospatial information acquired with Unmanned aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data *** consequence is a research and development focus on more accurately referenced images and derivatives,which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit(IMU)and Global Navigation Satellite System(GNSS)*** research evaluates the positional accuracy of the real-time kinematics(RTK)GNSS on the DJI Matrice 600 Pro,one of the first available and widely used UAVs with potentially surveying-grade *** a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI,the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not *** begin with,the actual GNSS RTK position of reference center(the physical point on the antenna)on the drone is not indicated,and uncertainty regarding this also exists among the professional user *** this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK *** RTK positioning data from the drone were then used for direct georeferencing,and its results were *** flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground,with a ground sampling distance of 1.3 *** against ground control points,the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 *** of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results.

关键词： UAV GNSS RTK direct georeferencing aerial triangulation lever arm offset

Modeling novel methodologies for unmanned aerial systems–Applications to the UAS-S4 Ehecatl and the UAS-S45 Bálaam

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Chinese Journal of Aeronautics 2019年第1期32卷 58-77页

作者： Maxime Alex Junior KUITCHE Ruxandra Mihaela BOTEZ ETS Laboratory of Active ControlsAvionics and AeroServoElasticity LARCASE

The rising demand for Unmanned aerial Systems(UASs) to perform tasks in hostile environments has emphasized the need for their simulation models for the preliminary evaluations of their missions. The efficiency of the UAS model is directly related to its capacity to estimate its flight dynamics with minimum computational resources. The literature describes several techniques to estimate accurate aircraft flight dynamics. Most of them are based on system identification. This paper presents an alternative methodology to obtain complete model of the S4 and S45 unmanned aerial systems. The UAS-S4 and the UAS-S45 models were divided into four sub-models, each corresponding to a specific discipline: aerodynamics, propulsion, mass and inertia, and actuator. The‘‘aerodynamic" sub-model was built using the Fderivatives in-house code, which is an improvement of the classical DATCOM procedure. The ‘‘propulsion" sub-model was obtained by coupling a two-stroke engine model based on the ideal Otto cycle and a Blade Element Theory(BET) analysis of the propeller. The ‘‘mass and the inertia" sub-model was designed utilizing the Raymer and DATCOM methodologies. A sub-model of an actuator using servomotor characteristics was employed to complete the model. The total model was then checked by validation of each submodel with numerical and experimental data. The results indicate that the obtained model was accurate and could be used to design a flight simulator.

关键词： Aerodynamics Aerospace propulsion Flight dynamics Unmanned aerial vehicles modeling

FBCRI Based Real-time Path Planning for Unmanned aerial Vehicles in Unknown Environments with Uncertainty

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机器人 2013年第6期35卷 641-650页

作者： LIU Wei HAO Peng ZHENG Zheng CAI Kaiyuan School of Automation Science and Electrical Engineering Beihang University Science and Technology on Aircraft Control Laboratory High-Tech Institute of Xi'an

This paper presents an FBCRI(feedback based compositional rule of inference)based novel path planning method to satisfy the requirements of real-time navigation,smoothness optimization and probabilistic obstacle *** local path-searching behaviors in regional ranges and global goal-seeking behaviors in holistic ranges,the method infers behavior weights using fuzzy reasoning embedded with feedback,and then coordinates the behaviors to generate new reference *** view of the deterministic decisions and the uncertain states of a UAV(unmanned air vehicle),chance constraints are adopted to probabilistically guarantee the UAV’s safety at a required *** results in representative scenes prove that the method is able to rapidly generate convergent paths in obstacle-rich environments,as well as highly improve the path quality with respect to smoothness and probabilistic safety.

关键词： unmanned aerial vehicle path planning fuzzy reasoning FBCRI(feedback based compositional rule of inference) uncertainty

Geo-location for Ground Target with Multiple Observations Using Unmanned aerial Vehicle

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第5期35卷 829-837页

作者： Xu Cheng He Chenglong Huang Daqing Key Laboratory of UAV’s Advanced Technology(Nanjing University of Aeronautics and Astronautics) Ministry of Industry and Information TechnologyNanjing 210016P.R.China State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang 050081P.R.China

In order to improve the target location accuracy of unmanned aerial vehicle(UAV),a novel target location method using multiple observations is ***,the camera intrinsic parameters are ***,the weighted least squares estimation is used to improve the localization precision because the traditional crossover method is vulnerable to noise and has low *** repeatedly measuring the same target point,a nonlinear observation equation is established and then covered to linear equations using Taylor *** weighted matrix is obtained according to the height of the measurement point and the camera optic axis pointing angle,and then the weighted least squares estimation is used to calculate the target position ***,the effectiveness and robustness of this method is verified by numerical simulation and flight *** results show that this method can effectively improve the precision of target location.

关键词： unmanned aerial vehicle target location camera calibration weighted least squares estimation

A two-stage optimization method for unmanned aerial vehicle inspection of an oil and gas pipeline network

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Petroleum Science 2019年第2期16卷 458-468页

作者： Yamin Yan Yongtu Liang Haoran Zhang Wan Zhang Huixia Feng Bohong Wang Qi Liao Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum-Beijing

Oil and gas pipeline networks are a key link in the coordinated development of oil and gas both upstream and *** improve the reliability and safety of the oil and gas pipeline network, inspections are implemented to minimize the risk of leakage, spill and theft, as well as documenting actual incidents. In recent years, unmanned aerial vehicles have been recognized as a promising option for inspection due to their high efficiency. However, the integrated optimization of unmanned aerial vehicle inspection for oil and gas pipeline networks, including physical feasibility, the performance of mission, cooperation, real-time implementation and three-dimensional(3-D) space, is a strategic problem due to its large-scale,complexity as well as the need for efficiency. In this work, a novel mixed-integer nonlinear programming model is proposed that takes into account the constraints of the mission scenario and the safety performance of unmanned aerial vehicles. To minimize the total length of the inspection path, the model is solved by a two-stage solution method. Finally, a virtual pipeline network and a practical pipeline network are set as two examples to demonstrate the performance of the optimization schemes. Moreover, compared with the traditional genetic algorithm and simulated annealing algorithm, the self-adaptive genetic simulated annealing algorithm proposed in this paper provides strong stability.

关键词： Pipeline network Unmanned aerial vehicle inspection Mixed-integer nonlinear programming Two-stage solution

Multi-objective Optimization Design of Vented Cylindrical Airbag Cushioning System for Unmanned aerial Vehicle

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第2期33卷 208-214页

作者： Shao Zhijian He Cheng Pei Jinhua Research Institute of Pilotless Aircraft Nanjing University of Aeronautics and Astronautics

Multi-objective optimization design of the gas-filled bag cushion landing system is ***,the landing process of airbag is decomposed into a adiabatic compression and a release of landing shock energy,and the differential equation of cylindrical gas-filled bag is presented from a theoretical perspective based on the ideal gas state equation and dynamic ***,the effects of exhaust areas and blasting pressure on buffer characteristics are studied,taking those parameters as design variable for the multiobjective optimization problem,and the solution can be determined by comparing Pareto set,which is gained by NSGA-Ⅱ.Finally,the feasibility of the design scheme is verified by experimental results of the ground test.

关键词： airbag vent orifice soft landing multi-objective optimization unmanned aerial vehicle (UAV)

PermissibleWind Conditions for Optimal Dynamic Soaring with a Small Unmanned aerial Vehicle

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Computer Modeling in Engineering & Sciences 2016年第6期111卷 531-565页

作者： Liu Duo-Neng Hou Zhong-Xi Guo Zheng Yang Xi-Xiang Gao Xian-Zhong College of Aerospace Sciences and Engineering National University of Defense TechnologyChangshaHunan410073China

Dynamic soaring is a flight maneuver to exploit gradient wind field to extend endurance and traveling *** trajectories for permissible wind conditions are generated for loitering dynamic soaring as well as for traveling patterns with a small unmanned aerial *** efficient direct collection approach based on the Runge-Kutta integrator is used to solve the optimization *** fast convergence of the optimization process leads to the potential for real-time *** on the results of trajectory optimizations,the general permissible wind conditions which involve the allowable power law exponents and feasible reference wind strengths supporting dynamic soaring are *** the smallest allowable wingtip clearance to trade for robustness and safety of the vehicle system and improving the maximum traveling speed results in shrunken permissible domain of wind conditions for loitering and traveling dynamic soaring *** analyses of vehicle model parameters show that properly reducing the wingspan and increasing the maximum lift-to-drag ratio and the wing loading can enlarge the permissible *** domains for different traveling directions show that the downwind dynamic soaring benefitting from the drift is more efficient than the upwind traveling pattern in terms of permissible domain size and net traveling speed.

关键词： Dynamic soaring Permissible wind conditions Trajectory optimization Unmanned aerial vehicle(UAV)

Measuring the area of cultivated land reclaimed from rural settlements using an unmanned aerial vehicle

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Journal of Geographical Sciences 2019年第5期29卷 846-860页

作者：杨存建许光洪李何超杨德菲黄河倪静李晓向筱 Research Center of Remote Sensing and Geographic Information System Application Key Laboratory of Land Resources Evaluation and Monitoring in SouthwestMinistry of EducationSichuan Normal University Chongqing University of Posts and Telecommunications Sichuan Land Consolidation and Rehabilitation Center College of Landscape Architecture Nanjing Forestry University College of Fundamental Education Sichuan Normal University Sichuan Land Survey and Planning Research Institute

Investigating and monitoring the area of cultivated land reclaimed from rural settlements is important to optimize rural land use and understand spatial patterns. Measuring cultivated land area is costly and inefficient, however, as this land use type is often widely dispersed and scattered. A new method is therefore explored in this study that utilizes a Phantom2 Vision +(P2V), one kind of Dajiang(DJI) unmanned aerial vehicle(UAV). The method proposed here includes generating rural settlement images using a P2V UAV, subsequently correcting them using a camera lens model, matching them with geo-coded high resolution alternatives, mosaicking them, measuring the area of cultivated land reclaimed from rural settlements, evaluating measurement accuracy, and analyzing overall *** results of this study show that use of a P2V UAV is reasonable in price, less than 8000 yuan(RMB), and that this method is able to measure cultivated land area reclaimed from rural settlements with 99% accuracy. This method is therefore low cost, highly efficient, and low risk, as well as being easy to learn and use. This UAV-based approach is also likely to be easily popularized and be particularly useful both for application across plains and flats as well as over mountains and hills. The method proposed in this study is also likely to prove beneficial for monitoring and managing rural land use and future consolidation.

关键词： unmanned aerial vehicle remote sensing reclaimed cultivated land rural settlements image mosaic

Photosynthetic Responses to Inorganic Carbon in Ulva lactuca Under Aquatic and aerial States

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Acta Botanica Sinica 2002年第11期44卷 1291-1296页

作者：邹定辉高坤山汕头大学科技中心海洋生物研究所广东汕头515063

Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated in the common intertidal macroalga Ulva lactuca L. along the coast of Shantou between aquatic and aerial state. The inorganic carbon dissolved in seawater at present could fully (at 10 ℃ or 20 ℃) or nearly (at 30 ℃) saturate the aquatic photosynthesis of U. lactuca . However, the aerial photosynthesis was limited by current ambient atmospheric CO 2 level, and such a limitation was more severe at higher temperature (20-30 ℃) than at lower temperature (10 ℃). The carbon_saturated maximal photosynthesis of U. lactuca under aerial state was much greater than that under aquatic state at 10 ℃ and 20 ℃, while the maximal photosynthesis under both states was similar at 30 ℃. The aerial values of K m (CO 2) for photosynthesis were higher than the aquatic values. On the contrary, the values of apparent photosynthetic CO 2 conductance under aerial state were considerably lower than that under aquatic state. It was concluded that the increase of atmospheric CO 2 would enhance the primary productivity of U. lactuca through stimulating the photosynthesis under aerial state during low tide.

关键词： Ulva lactuca photosynthesis inorganic carbon aquatic aerial atmospheric CO 2 rise