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[IEEE 2019 6th International Conference on Control, Decision and Information Technologies (CoDIT) - Paris, France (2019.4.23-2019.4.26)] 2019 6th International Conference on Control, Decision and Information Technologies (CoDIT) - 3D Mapping Based on Fusion of 2D Laser and IMU Data Acquired by Unmanned Aerial Vehicle
摘要： The paper deals with the three-dimensional (3D) modelling based on data acquired from 2D laser sensor and IMU (Inertial Measurement Unit) attached to the UAV (Unmanned Aerial Vehicle). The used multi-sensor unit produces 2D scans and provides information about Euler angles or quaternions. These angles are used to describe the UAV orientation in 3D space, more precisely the orientation of the laser sensor. In order to generate 3D occupancy map it is necessary to rotate the laser sensor around its axis yielding the 2D scans being mapped on 3D space using quaternions. Inertial sensor and Sweep LiDAR laser measurements are transmitted to the single board computer Odroid XU4 (SBC). The data fusion was performed under ROS (Robot Operating System) installed on the SBC, producing 3D space points. These points are transmitted over the network to the central computer on which the UAV localization and mapping processes are done within the ROS. The effectiveness of the proposed system for 3D modelling of the UAV environment is verified by experiment.
关键词： 2D laser,Octree,ICP,UAV,ROS,3D mapping,IMU,SLAM
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Intelligent Techniques in Control, Optimization and Signal Processing (INCOS) - Tamilnadu, India (2019.4.11-2019.4.13)] 2019 IEEE International Conference on Intelligent Techniques in Control, Optimization and Signal Processing (INCOS) - Implementation of MPPT for Flexible Solar Cells embedded on Unmanned Aerial Vehicles
摘要： This paper presents a Maximum Power Point Tracking (MPPT)method for a flexible organic polymer solar cell (FOPSC) under varyingshading condition. FOPSC was fabricated using a composite of three conjugated polymers namely PFO, PEO-at-co-MEH-PPV, and MEH-PPV as active layer, CNT/rGO composite as counter electrode (CE), substratemade of Poly-Ethylene Terephthalate (PET). The fabricated OPSC showed around 0.69 asfill factor (FF), a 0.67 V of voltage at open circuit condition(Voc), a 6.37% of 13.69 power mA/cm2 circuit density condition.The PCE of OPSC was comparable to that of OPSC with Pt CE (η = 7.82%).Four OPSC strips where connected in series, aground-based UAV model and different shading conditions were recreated and the power to voltage relationships were obtained. Based on the experimental data obtained, a MPPT techniques was developed using second order derivative of output voltagewith respect to duty cycle The buck a ratio PWM controlled using a microcontroller to implement the D2VOC based MPPT.
关键词： MPPT and UAV,TEM,organic polymer solar cell,CNT/rGO composite,second order derivative of output voltagewith respect to duty cycle ratio (D2VOC),FEM
更新于2025-09-16 10:30:52
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A UAV-Mounted Free Space Optical Communication: Trajectory Optimization for Flight Time
摘要： In this work, we address the trajectory optimization of a fixed-wing unmanned aerial vehicle (UAV) using free space optical communication (FSOC). Here, we focus on maximizing the flight time of the UAV by considering practical constraints for wireless UAV communication, including limited propulsion energy and required data rates. We find optimized trajectories in various atmospheric environments (e.g., moderate-fog and heavy-fog conditions), while also considering the channel characteristics of FSOC. In addition to maximizing the flight time, we consider the energy efficiency maximization and operation-time minimization problem to find the suboptimal solutions required to meet those constraints. Furthermore, we introduce a low-complexity approach to the proposed framework. In order to address the optimization problem, we conduct a bisection method and sequential programming and introduce a new feasibility check algorithm. Although our design considers suboptimal solutions owing to the nonconvexity of the problems, our simulations indicate that the proposed scheme exhibits a gain of approximately 44.12% in terms of service time when compared to the conventional scheme.
关键词： trajectory design,Free space optical communication (FSOC),wireless communications with an unmanned aerial vehicle (UAV),flight time maximization,UAV-mounted FSOC
更新于2025-09-12 10:27:22
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Non-destructive tree volume estimation through quantitative structure modelling: Comparing UAV laser scanning with terrestrial LIDAR
摘要： Above-Ground Biomass (AGB) product calibration and validation require ground reference plots at hectometric scales to match space-borne missions' resolution. Traditional forest inventory methods that use allometric equations for single tree AGB estimation suffer from biases and low accuracy, especially when dealing with large trees. Terrestrial Laser Scanning (TLS) and explicit tree modelling show high potential for direct estimates of tree volume, but at the cost of time demanding fieldwork. This study aimed to assess if novel Unmanned Aerial Vehicle Laser Scanning (UAV-LS) could overcome this limitation, while delivering comparable results. For this purpose, the performance of UAV-LS in comparison with TLS for explicit tree modelling was tested in a Dutch temperate forest. In total, 200 trees with Diameter at Breast Height (DBH) ranging from 6 to 91 cm from 5 stands, including coniferous and deciduous species, have been scanned, segmented and subsequently modelled with TreeQSM. TreeQSM is a method that builds explicit tree models from laser scanner point clouds. Direct comparison with TLS derived models showed that UAV-LS reliably modelled the volume of trunks and branches with diameter ≥30 cm in the mature beech and oak stand with Concordance Correlation Coefficient (CCC) of 0.85 and RMSE of1.12 m3. Including smaller branch volume led to a considerable overestimation and decrease in correspondence to CCC of 0.51 and increase in RMSE to 6.59 m3. Denser stands prevented sensing of trunks and further decreased CCC to 0.36 in the Norway spruce stand. Also small, young trees posed problems by preventing a proper depiction of the trunk circumference and decreased CCC to 0.01. This dependence on stand indicated a strong impact of canopy structure on the UAV-LS volume modelling capacity. Improved flight paths, repeated acquisition flights or alternative modelling strategies could improve UAV-LS modelling performance under these conditions. This study contributes to the use of UAV-LS for fast tree volume and AGB estimation on scales relevant for satellite AGB product calibration and validation.
关键词： Above-Ground Biomass (AGB),Forest,UAV,Laser scanning,Quantitative Structure Model (QSM)
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Torino, Italy (2019.6.19-2019.6.21)] 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Wireless Local Positioning System for Controlled UAV Landing in GNSS-Denied Environment
摘要： A novel concept for ad-hoc landing of unmanned aerial vehicles (UAV) in GNSS-denied environment is presented in this paper. In our concept at the beginning of the landing phase the UAV drops several active beacons down to the landing site. It enables the UAV to localize itself via distance and angle information to the deployed beacons. The presented wireless local positioning system is based on 24 GHz secondary radar sensors and allows for accurate and robust 3D-positioning even in harsh weather conditions. The specially designed antennas with large angular coverage assure UAV localization disregarding the beacon’s position and orientation. The developed beacon design has small size, low weight and power consumption that perfectly suits the application goal. Measurements of localization and landing scenario using four beacons and the radar unit installed on the drone are shown. The 3D-positioning of the UAV with the RMSE under 36 cm using only a single beacon and 31 cm using four beacons were achieved. These results verify the application of the proposed system as an accurate and redundant UAV landing solution.
关键词： UAV,landing,local positioning system,wireless localization
更新于2025-09-11 14:15:04
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Feasibility analysis of laser detection and positioning for unmanned aerial vehicles
摘要： In order to carry out effective anti-reconnaissance for unmanned aerial vehicles（UAV）, the feasibility of effective monitoring of UAV by laser detection system has been analyzed. The models of laser transmitting and receiving system and the photoelectric imaging system on UAV are established. The characteristics of specular scattering and focal plane reflection of UAV imaging lens are simulated. Taking the UAV located at a height of 10,000 m as an example, the feasibility of the application of two detection systems under reflected light has been analyzed. The range of incident angle of the detection laser, the distribution characteristics of light intensity on the photosensitive surface of the detection system and the variation characteristics of return light of the detection laser during dynamic scanning have been obtained respectively. The results show that the focal plane reflected light intensity of the UAV imaging lens is much higher than that of the specular scattered light intensity, and has a good return characteristic. Within the field coverage of the UAV imaging system, the focus plane reflected light can be used to effectively detect and locate the UAV target.
关键词： laser detection,UAV,focal plane reflection,anti-reconnaissance,specular scattering
更新于2025-09-11 14:15:04
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[American Society of Agricultural and Biological Engineers 2019 Boston, Massachusetts July 7- July 10, 2019 - ()] 2019 Boston, Massachusetts July 7- July 10, 2019 - <i>Laser detection of the boundary of UAV spray operation</i>
摘要： The agricultural plant protection UAV is beneficial to reducing pesticide, improving utilization rate, reducing harm to human beings and animals. The boundary detection and identification of the drone spray operation is an important aspect of the UAV spraying. The two-dimensional laser scanning range finder has the function of measuring object reflection characteristics. In order to obtain the detailed field information in the sampling interval, the laser detection system constructed not only measures the distance from the UAV to the rice and ridge, but also measures the reflection value of the rice and ridge. The distance between the rice and ridge is used as the threshold to identify the boundary. The signal division point appears near 1m with a variance of 0.27m. In the process of segmentation, there are many misjudgment points on the left side of the laser emission origin. Accurate identification of boundaries can provide a basis for path planning, especially the UAV spraying.
关键词： Boundary identification,UAV,2D Laser Range finder,Height measurement,GPS
更新于2025-09-11 14:15:04
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Species discrimination and individual tree detection for predicting main dendrometric characteristics in mixed temperate forests by use of airborne laser scanning and ultra-high-resolution imagery
摘要： This study aims to investigate the combined use of two types of remote sensing data — ALS derived and digital aerial photogrammetry data (based on imagery collected by airborne UAV sensors) — along with intensive field measurements for extracting and predicting tree and stand parameters in even-aged mixed forests. The study is located in South West Romania and analyzes data collected from mixed-species plots. The main tree species within each plot are Norway spruce (Picea abies L. Karst.) and Beech (Fagus sylvatica L.). The ALS data were used to extract the digital terrain model (DTM), digital surface model (DSM) and normalized canopy height model (CHM). Object-Based Image Analysis (OBIA) classification was performed to automatically detect and separate the main tree species. A local filtering algorithm with a canopy-height based variable window size was applied to identify the position, height and crown diameter of the main tree species within each plot. The filter was separately applied for each of the plots and for the areas covered with Norway spruce and beech trees, respectively (i.e. as resulted from OBIA classification). The dbh was predicted based on ALS data by statistical Monte Carlo simulations and a linear regression model that relates field dbh for each tree species with their corresponding ALS-derived tree height and crown diameter. The overall RMSE for each of the tree species within all the plots was 5.8 cm for the Norway spruce trees, respectively 5.9 cm for the beech trees. The results indicate a higher individual tree detection rate and subsequently a more precise estimation of dendrometric parameters for Norway spruce compared to beech trees located in spruce-beech even-aged mixed stands. Further investigations are required, particularly in the case of choosing the best method for individual tree detection of beech trees located in temperate even-aged mixed stands.
关键词： Monte Carlo simulation,ALS,Forest inventory,UAV,OBIA
更新于2025-09-11 14:15:04
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A comparison of UAV laser scanning, photogrammetry and airborne laser scanning for precision inventory of small-forest properties
摘要： This study addresses the use of multiple sources of auxiliary data from unmanned aerial vehicles (UAVs) and airborne laser scanning (ALS) data for inference on key biophysical parameters in small forest properties (5–300 ha). We compared the precision of the estimates using plot data alone under a design-based inference with model-based estimates that include plot data and the following four types of auxiliary data: (1) terrain-independent variables from UAV photogrammetric data (UAV-SfM); (2) variables obtained from UAV photogrammetric data normalized using external terrain data (UAV-SfMDTM); (3) UAV-LS and (4) ALS data. The inclusion of remotely sensed data increased the precision of DB estimates by factors of 1.5–2.2. The optimal data sources for top height, stem density, basal area and total stem volume were: UAV-LS, UAV-SfM, UAV-SfMDTM and UAV-SfMDTM. We conclude that the use of UAV data can increase the precision of stand-level estimates even under intensive ?eld sampling conditions.
关键词： UAV,laser scanning,photogrammetry,forest inventory,precision forestry,ALS
更新于2025-09-11 14:15:04
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NRLI-UAV: Non-rigid registration of sequential raw laser scans and images for low-cost UAV LiDAR point cloud quality improvement
摘要： Accurate registration of light detection and ranging (LiDAR) point clouds and images is a prerequisite for integrating the spectral and geometrical information collected by low-cost unmanned aerial vehicle (UAV) systems. Most registration approaches take the directly georeferenced LiDAR point cloud as a rigid body, based on the assumption that the high-precision positioning and orientation system (POS) in the LiDAR system provides sufficient precision, and that the POS errors are negligible. However, due to the large errors of the low-precision POSs commonly used in the low-cost UAV LiDAR systems (ULSs), dramatic deformation may exist in the directly georeferenced ULS point cloud, resulting in non-rigid transformation between the images and the deformed ULS point cloud. As a result, registration may fail when using a rigid transformation between the images and the directly georeferenced LiDAR point clouds. To address this problem, we proposed NRLI-UAV, which is a non-rigid registration method for registration of sequential raw laser scans and images collected by low-cost UAV systems. NRLI-UAV is a two-step registration method that exploits trajectory correction and discrepancy minimization between the depths derived from structure from motion (SfM) and the raw laser scans to achieve LiDAR point cloud quality improvement. Firstly, the coarse registration procedure utilizes global navigation satellite system (GNSS) and inertial measurement unit (IMU)-aided SfM to obtain accurate image orientation and corrects the errors of the low-precision POS. Secondly, the fine registration procedure transforms the original 2D-3D registration to 3D-3D registration. This is performed by setting the oriented images as the reference, and iteratively minimizing the discrepancy between the depth maps derived from SfM and the raw laser scans, resulting in accurate registration between the images and the LiDAR point clouds. In addition, an improved LiDAR point cloud is generated in the mapping frame. Experiments were conducted with data collected by a low-cost UAV system in three challenging scenes to evaluate NRLI-UAV. The final registration errors of the images and the LiDAR point cloud are less than one pixel in image space and less than 0.13 m in object space. The LiDAR point cloud quality was also evaluated by plane fitting, and the results show that the LiDAR point cloud quality is improved by 8.8 times from 0.45 m (root-mean-square error [RMSE] of plane fitting) to 0.05 m (RMSE of plane fitting) using NRLI-UAV, demonstrating a high level of automation, robustness, and accuracy.
关键词： Low-cost,Light detection and ranging (LiDAR),Unmanned aerial vehicle (UAV),Image sequence,Non-rigid registration
更新于2025-09-11 14:15:04