UAV or Drones for Remote Sensing Applications in GPS/GNSS Enabled and GPS/GNSS Denied Environments

The design of novel UAV systems and the use of UAV platforms integrated with robotic sensing and imaging techniques, as well as the development of processing workflows and the capacity of ultra-high temporal and spatial resolution data, have enabled a rapid uptake of UAVs and drones across several industries and application domains.This book provides a forum for high-quality peer-reviewed papers that broaden awareness and understanding of single- and multiple-UAV developments for remote sensing applications, and associated developments in sensor technology, data processing and communications, and UAV system design and sensing capabilities in GPS-enabled and, more broadly, Global Navigation Satellite System (GNSS)-enabled and GPS/GNSS-denied environments.Contributions include:UAV-based photogrammetry, laser scanning, multispectral imaging, hyperspectral imaging, and thermal imaging;UAV sensor applications; spatial ecology; pest detection; reef; forestry; volcanology; precision agriculture wildlife species tracking; search and rescue; target tracking; atmosphere monitoring; chemical, biological, and natural disaster phenomena; fire prevention, flood prevention; volcanic monitoring; pollution monitoring; microclimates; and land use;Wildlife and target detection and recognition from UAV imagery using deep learning and machine learning techniques;UAV-based change detection

대형 폐기물량 산정을 위한 UAS와 TLS 기반 공간정보 구축기법 연구

학위논문(박사)--서울대학교 대학원 :환경대학원 협동과정 조경학,2019. 8. 이동근.대형재난 발생에 대한 사전예방부터 대응단계까지 전과정의 체계적이고 효율적인 대처를 통해 인명, 재산, 환경 등의 피해를 최소화하여야 한다. 본 연구는 대형재난 발생 시 대응 과정 중 폐기물량 산정에 집중하여 연구를 수행하였다. 대형폐기물량 산정에 대한 연구는 과거부터 수행되고 있지만 실질적인 측정이 어렵기 때문에 발생 이전의 정보를 이용하여 모델링, 원격탐사 등의 기술을 이용하여 폐기물량을 예측하는 연구가 다수 수행되고 있다. 본 연구에서는 최근 활발하게 이용되고 있는 UAS (Unmanned Aerial System)를 기반으로 폐기물량을 산정하고 정확도를 평가하며 기존 기술과의 비교와 분석을 수행하고자 하였다. UAS는 UAV (Unmanned Aerial Vehicle)를 이용하여 영상을 취득하고 분석하는 전반적인 과정이라고 볼 수 있다. UAS를 이용하여 3차원 공간정보를 구축하고 정확도를 평가하는 연구가 과거부터 주로 수행되고 있으며 다양한 분야에 적용되고 있다. 이와 유사하게 TLS (Terrestrial Laser Scanning)를 이용하여 3차원 공간정보를 구축할 수 있는데 측량 분야에서 주로 이용되고 있으며 그 정확성 또한 우수하여 식생, 건축, 토목, 문화재, 지형측량 등 다양한 분야에서 널리 이용되고 있다. 대형폐기물량 또한 TLS를 이용하여 3차원 공간정보 구축 후 산정할 수 있지만 비용, 시간 등의 제약사항으로 인해 활용이 불가능하다고 볼 수 있다. 본 연구는 크게 3가지 부분으로 구분할 수 있다. 첫 번째는 UAS를 이용한 3차원 공간정보 구축과 폐기물량 산정 가능성 모색이다. UAS를 이용하여 3차원 공간정보 구축까지의 과정을 정밀 분석하여 최적의 비행변수와 기타 변수를 도출하여 폐기물량 산정의 가능성을 보고자 하였다. 두 번째는 TLS 기술과 UAS 기술 기반의 3차원 공간정보의 비교와 분석이다. 각각의 3차원 공간정보를 M3C2알고리즘을 이용하여 비교하고 분석하여 최적의 폐기물량 산정 기법을 도출하고자 하였다. 마지막으로 세 번째는 3차원 공간정보의 융합과 효율성 분석이다. 두 가지 기술을 융합하여 3차원 공간정보를 구축하고 효율성을 분석하여 UAS, TLS, 융합기법 세가지 방법론간의 차이와 최적의 폐기물량 산정 기법을 도출하고자 하였다. 주요 비행변수는 비행고도와 영상의 중복도이며 이외 변수는 지상기준점 개수이다. 이 외에도 카메라 내부표정, 짐벌의 흔들림 정도를 분석하였다. 본 연구를 통해 56개의 케이스 중 최적의 변수를 도출하였으며 과거 연구와는 다르게 고도차이가 많이 나는 폐기물 지역에서는 DW (Distance covered on the ground by on image in Width direction)에 의해 결과가 도출되었다. 일반적으로 고도가 낮을수록 높은 정확도를 가지는 3차원 공간정보를 구축하지만 본 연구에서는 고도가 낮을수록 정확도가 낮아지는 것을 확인하였다. 56개의 케이스 모두 정확도 분석을 실시하였으며 정확도와 폐기물량간의 상관성이 있음을 도출하였다. 3차원 공간정보의 정확도가 높을수록 산정한 폐기물량이 유사했으며 이와 반대로 정확도가 낮은 3차원 공간정보들에서는 폐기물량이 제각각으로 나타나는 것을 확인할 수 있었다. 이러한 일련의 과정을 통해 폐기물량 산정을 위한 UAS 최적 변수를 도출하였으며 3차원 공간정보 기반의 폐기물량 산정 가능성을 확인할 수 있었다. M3C2알고리즘을 이용하여 UAS와 TLS 기반의 3차원 공간정보를 비교하였으며 이를 통해, 각각의 공간정보가 가지고 있는 장단점을 확인할 수 있었다. 정확도의 경우, UAS기반 3차원 공간정보의 RMSE는 0.032m, TLS의 RMSE는 0.202m로 UAS의 정확도가 더 높은 것으로 나타났다. 두 가지 기술을 융합한 3차원 공간정보의 RMSE는 0.030m로써 세 가지 방법론 중에서 가장 높은 정확도를 보였다. 하지만 효율성 관점에서 분석한 결과, UAS 기반의 3차원 공간정보가 단시간에 높은 정확도를 보이는 결과로 도출됨으로써 대형폐기물량 산정에 최적화된 기술과 방법론을 가지고 있는 것으로 확인할 수 있었다. 이 외에도 비용을 분석한 결과, UAS 기반의 3차원 모형 구축까지 소비된 비용이 TLS에 비해 적은 비용이 소비된 것을 확인할 수 있었다. 대형재난 시 비교적 단시간에 대응하여 피해를 최소화 하고 다양한 의사결정을 진행해야 하는데, 본 연구를 통해 도출한 UAS 기반의 3차원 공간정보 구축 기법은 대형 폐기물량산정과 공간적 의사결정에 활용할 수 있을 기대한다.Damage to people, property, and the environment must be minimized through systematic and efficient handling of large-scale disasters throughout the entire process from prevention to the response stage. This study focused on the waste quantity calculations that are part of the response process during large-scale disasters. Studies on large-scale waste quantity calculations have been performed in the past, but actual measurements are difficult. Therefore, many studies are being performed on using information from previous instances to perform modeling and using technologies such as remote sensing to estimate waste quantities. This study calculated waste quantities based on UAS (unmanned aerial system), which is a technology that is often used these days. It evaluated the accuracy of this technology, and it analyzed and compared the technology with existing technologies. UAS can be seen as an overall process of using UAVs (Unmanned Aerial Vehicle) to capture images and analyzing them. Studies have been conducted in the past on using UAS to build 3D spatial information and evaluate accuracy, and they are being used integrally in a variety of fields. Similarly, 3D spatial information can be built using TLS (Terrestrial Laser Scanning), and these are chiefly used in the surveying field. This methods accuracy is excellent, and it is widely used in a variety of fields such as vegetation, construction, civil engineering, cultural assets, and topographical surveys. Large-scale waste can also be calculated by using TLS to build a 3D spatial information, but it is seen as unfeasible to use due to cost and time limitations. This study is broadly divided into 3 parts. The first part is examining the feasibility of using UAS to build a 3D spatial information and calculate waste quantity. The process up to the point of using UAS to build a 3D spatial information was analyzed in detail, and optimal flight variables and other variables were found in order to examine the feasibility of calculating waste quantity. The second part is comparing and analyzing 3D spatial information based on TLS and UAS technology. The 3D spatial information were compared and analyzed using the M3C2 algorithm, and the optimal waste quantity calculation methods were found. Finally, the third part is analyzing a combination of the 3D spatial information and the 3D spatial information efficiency. The two technologies were combined to build a 3D spatial information, and their efficiency was analyzed to find the differences between the three methodologies (UAS, TLS, and the combined method), as well as find the optimal waste quantity calculation method. The major flight variables are the flight altitude and image overlap. Another variable is the number of ground control points. In addition to this, the camera interior orientation and degree of gimbal shaking were analyzed. Through this study, the optimal variables among 56 cases were found. Unlike past studies, it was discovered that the results were contrary to previous studies due to the DW (Distance covered on the ground by on image in Width direction) in waste regions with a lot of altitude differences. Normally, as the altitude becomes lower, the accuracy of the 3D spatial information becomes higher, but in this study it was found that the accuracy became lower as the altitude became lower. The accuracy of all 56 cases was analyzed, and it was found that there is a correlation between accuracy and the amount of waste. As the accuracy of the 3D spatial information increased, the calculated waste amounts became similar. Conversely, in 3D spatial information with low accuracy, it was found that the waste amounts were different. Through this sequential process, the optimal UAS variables for calculating waste amounts were found, and it was possible to confirm the feasibility of calculating waste amounts based on 3D spatial iformation. The M3C2 algorithm was used to compare the UAS and TLS-based 3D spatial information, and by doing so, it was possible to confirm the advantages and disadvantages of each model. As for accuracy, the RMSE of the UAS-based 3D spatial information was 0.032 m, and the RMSE of the TLS model was 0.202, making the UAS models accuracy higher. The RMSE of the 3D spatial information which combined the two technologies was 0.030 m, and it showed the highest accuracy of the three methodologies. However, in terms of efficiency, the analyzed results were able to confirm that the UAS-based 3D spatial information had the optimal technology and methodology for large-scale waste amount calculations by creating a model which shows high accuracy in a short time. In addition, cost analysis results were able to confirm that the cost of building the UAS-based 3D spatial information was lower than that of TLS. During large-scale disasters, it is necessary to respond in a relatively short time to minimize damage and perform a variety of decision-making. The UAS-based 3D spatial information building method found in this study can be used for large-scale waste amount calculations and spatial decision-making.I. Introduction 1 II. Literature Review 7 1. Studies on Applying the UAS to Disaster Management 7 2. Accuracy of UAS-based 3D Model Construction 14 3. Disaster Waste Quantity 26 III. Materials and Methods 34 1. Optimal Flight Parameters for UAV Generating 3D Spatial Information 36 1.1. Design of UAV Flight 36 1.2. Photogrammetric Processing for the Acquisition of 3D Spatial Information 41 1.3. Assessment of the 3D Spatial Information Accuracy 43 1.4. Computation of the Amount of Waste 45 2. Comparison and Analysis of TLS and UAS Methodology for Optimal Volume Computation 47 2.1. TLS and UAS-based 3D Spatial Information Generation and Volume Computation 49 2.2. Comparison and Analysis of 3D Spatial Information 55 3. Multispace Fusion Methodology-based 3D Spatial Information Generating and Efficiency Analysis 57 3.1. Multispace Fusion Methodology-based 3D Spatial Information 57 3.2. Efficiency Analysis of 3D Spatial Information for Responding to Large-scale Disasters 58 III. Result and Discussion 59 1. Optimal Flight Parameters for UAV Generating 3D Spatial Information and Investigation of Feasibility 59 1.1. Generation of 3D Spatial Information using UAS 59 1.2. Assessment of the 3D Spatial Information Accuracy 64 1.3. Computation of the Amount of Waste and Optimal flights parameters 76 2. Comparison and Analysis of TLS and UAS-based 3D Spatial Information 84 2.1. Generation of 3D Spatial Information and Volume Computation using UAS 84 2.2. Spatial Comparison and Analysis 88 3. Multispace Fusion Methodology-based 3D Spatial Information Generating and Efficiency Analysis 93 3.1. Multispace Fusion Methodology-based 3D Spatial Information 93 3.2. 3D Spatial information Efficiency Analysis for Responding to Large-scale Disasters 96 IV. Conclusion 100 V. Bibliography 103Docto

Discrete and Distributed Error Assessment of UAS- SfM Point Clouds of Roadways

Perishable surveying, mapping, and post-disaster damage data typically require efficient and rapid field collection techniques. Such datasets permit highly detailed site investigation and characterization of civil infrastructure systems. One of the more common methods to collect, preserve, and reconstruct three-dimensional scenes digitally, is the use of an unpiloted aerial system (UAS), commonly known as a drone. Onboard photographic payloads permit scene reconstruction via structure-from-motion (SfM); however, such approaches often require direct site access and survey points for accurate and verified results, which may limit its efficiency. In this paper, the impact of the number and distribution of ground control points within a UAS SfM point cloud is evaluated in terms of error. This study is primarily motivated by the need to understand how the accuracy would vary if site access is not possible or limited. In this paper, the focus is on two remote sensing case studies, including a 0.75 by 0.50-km region of interest that contains a bridge structure, paved and gravel roadways, vegetation with a moderate elevation range of 24 m, and a low-volume gravel road of 1.0 km in length with a modest elevation range of 9 m, which represent two different site geometries. While other studies have focused primarily on the accuracy at discrete locations via checkpoints, this study examines the distributed errors throughout the region of interest via complementary light detection and ranging (lidar) datasets collected at the same time. Moreover, the international roughness index (IRI), a professional roadway surface standard, is quantified to demonstrate the impact of errors on roadway quality parameters. Via quantification and comparison of the differences, guidance is provided on the optimal number of ground control points required for a time-efficient remote UAS survey

Review article: The use of remotely piloted aircraft systems (RPASs) for natural hazards monitoring and management

The number of scientific studies that consider possible applications of remotely piloted aircraft systems (RPASs) for the management of natural hazards effects and the identification of occurred damages strongly increased in the last decade. Nowadays, in the scientific community, the use of these systems is not a novelty, but a deeper analysis of the literature shows a lack of codified complex methodologies that can be used not only for scientific experiments but also for normal codified emergency operations. RPASs can acquire on-demand ultra-high-resolution images that can be used for the identification of active processes such as landslides or volcanic activities but can also define the effects of earthquakes, wildfires and floods. In this paper, we present a review of published literature that describes experimental methodologies developed for the study and monitoring of natural hazard

Merging Unmanned Aerial System and Laser Scanning techniques for high resolution 3D modelling of Koutouki Cave, Attica

Η επιστήμη της τηλεανίχνευσης και η τεχνολογία σάρωσης αναγλύφου με λέιζερ μας έδωσαν την ευκαιρία να μελετήσουμε κλειστούς χώρους και περιβάλλοντα όπως τα σπήλαια με τη σύνθετη και μοναδική μορφολογία τους. Στόχος της παρούσας μεταπτυχιακής διατριβής είναι η δημιουργία ενός ολοκληρωμένου τρισδιάστατου μοντέλου του σπηλαίου Κουτούκι στην Παιανία, η ποσοτική ανάλυση των γεωμορφών που συνθέτουν το σπήλαιο και το πάχος των υπερκειμένων στρωμάτων πάνω από το σπήλαιο. Χρησιμοποιήσαμε ένα laser scanner χειρός για την απόκτηση 80.000.000 σημείων με πραγματικές συντεταγμένες (X, Y, Z) για την αποτύπωση ολόκληρου του σπηλαίου συμπεριλαμβανομένων των μικρότερων διαδρομών και των σκοτεινών τμημάτων. Το νέφος σημείων αποτελείται από το δάπεδο, τα τοιχώματα και την οροφή του σπηλαίου, καθώς και τους σταλακτίτες, τους σταλαγμίτες και τις κολόνες που αποτελούν τη διακόσμηση του σπηλαίου. Η απόλυτη και ακριβής τοποθέτηση του νέφους σημείων μέσα σε ένα σύστημα αναφοράς μας δίνει την ευκαιρία για τρισδιάστατες μετρήσεις και την λεπτομερή απεικόνιση των γεωμορφών. Δημιουργώντας το ψηφιακό μοντέλο αναγλύφου του δαπέδου του σπηλαίου, εντοπίσαμε 55 κολόνες όπου με στατιστική ανάλυση μπορέσαμε να τις συσχετίσουμε με το πλαίσιο της ανάπτυξης του σπηλαίου. Οι παράμετροι που προκύπτουν είναι οι ισοϋψείς του σπηλαίου, το ύψος, η γεωμετρία και ο όγκος της κάθε κολόνας, καθώς και ο όγκος της κοιλότητας του ανοιχτού χώρου. Επιπλέον, με τη χρήση μη επανδρωμένου αεροσκάφους και εφαρμόζοντας μια μεθοδολογία βασισμένη στη φωτογραμμετρική επεξεργασία των δεδομένων εικόνας, πραγματοποιήθηκε η σάρωση του αναγλύφου πάνω από το σπήλαιο που μας οδήγησε στην παραγωγή ενός ψηφιακού μοντέλου αναγλύφου του πρανούς. Το τελικό προϊόν είναι ένα επίπεδο πληροφορίας υψηλής ανάλυσης με τις μετρήσεις του πάχους των υπερκειμένων στρωμάτων του σπηλαίου καθώς και τις τοπογραφίας με υψηλή ακρίβεια. Υποστηρίζουμε ότι, με την αποδεδειγμένη μεθοδολογία, είναι δυνατόν να εντοπίσουμε με μεγάλη λεπτομέρεια και ακρίβεια τα γεωμορφολογικά χαρακτηριστικά ενός σπηλαίου, να κάνουμε εκτιμήσεις για τη σπηλαιογένεση ενός σπηλαίου και να παρακολουθήσουμε την εξέλιξη ενός καρστικού συστήματος.Remote sensing techniques and laser scanning technology have given us the opportunity to study indoor environments such as caves with their complex and unique morphology. The objective of this Msc thesis is the generation of a complete 3D model of the Koutouki Cave in Peania, Greece, the quantification analysis of the subsurface structures that consists the cave, and the thickness of the bedding between the cave and the surface. We used a handheld laser scanner for acquiring 80,000,000 points with projected coordinate information (X, Y, Z) covering the entire show cave of Koutouki, including its hidden passages and dark corners. The point cloud covers the floor, the walls and the roof of the cave, as well as the stalactites, stalagmites and the connected columns that constitute the decoration of the cave. The absolute and exact placement of the point cloud within a geographic reference frame gives us the opportunity for three-dimensional measurements and detailed visualization of the subsurface structures. Using open - source software, we managed to make a quantification analysis of the terrain and generate morphological and geometric features of the speleothems. We identified 55 columns by using digital terrain analysis and processed them statistically in order to correlate them to the frame of the cave development. The parameters that derived are the contours, each column height, the speleothem geometry and volume, as well as the volume of the open space cavity. Furthermore, we applied a methodology based on photogrammetric processing of Unmanned Aerial System image data which led us to the production of a digital terrain model of the open-air surface above the cave. The final product is a high-resolution information layer with measurements of the rock thickness between the roof of the underground karstic structure and the open-surface topography with high accuracy. We argue that, by the demonstrated methodology, it is possible to identify with high accuracy and detail the geomorphological features of a cave, estimate the speleogenesis and monitor the evolution of a karstic system

UAVs for the Environmental Sciences

This book gives an overview of the usage of UAVs in environmental sciences covering technical basics, data acquisition with different sensors, data processing schemes and illustrating various examples of application

Building an Aerial-Ground Robotics System for Precision Farming: An Adaptable Solution

[No abstract available