Analysis of the effects on the pitching, rolling and yawing rate of a v-tail configured quadcopter

Many different projects have been focused on multirotor aircraft, especially on quadcopters, but there are only a few papers relating to the dynamic effects on quadcopters with tilted motors. In this paper, a quadcopter has been modelled to allow flight simulation under differing motor tilt angle configurations. The simulation has also been validated by building a quadcopter of known physical attributes and with on-board instrumentation and telemetry to log its attitude and motor control inputs (PWM signals). The conversion from a PWM signal to the rpm was achieved by determining the relationship between the PWM signal and the thrust generated. Both of these parameters being recorded on a test bench. Thrust is calculated for each motor individually, since the angled motors generate different advance ratios and hence different thrust coefficients. The main focus of this research was on the effect of the different coefficients and the thrust components acting in the x-y plane of the quadcopter body frame

U.ph.o and mago: Two useful instruments in support of photogrammetric uav survey

In emergency and critical scenarios, the UAV could play a key role in accessing unreachable sites in a safe and rapid way, guaranteeing at the same time the necessary accuracy and precision of the survey. In this context, UAV survey campaigns have been performed by the authors in Norcia (Italy), hit by tragic seismic events in August and October 2016. The surveys were motivated by the artistic and historical value of monuments, the need to plan and design the restoring and retrofitting of buildings, and also to quantify and manage the ruins. Goal of such surveys was the description of the structures geometry with a centimetric precision and a high level of reliability. Recently, the authors have conceived two tools, U.Ph.O (Unmanned Photogrammetric Office) and MAGO (Adaptive Mesh for Orthophoto Generation), dedicated to the planning and restitution phases of the survey, respectively. U.Ph.O. and MAGO are here applied to two different buildings in Norcia, i.e. the Civic Tower of Norcia and San Salvatore Church of Campi di Norcia. The former is a standing-out structure, surrounded by the complex of the historical centre, while the latter is located in an isolated site in the countryside. These features make the survey planning and the orthophoto reconstruction completely different, mainly due to the different optimal shooting geometry and the presence or absence of obstructions

Graphical tools to the rescue. high resolution aerial photography for the location of missing persons

Since the COVID-19 pandemic changed the rules of the game in many work envi-ronments, adaptation has been a key factor. Restrictions such as social distance or confinement made searches for missing persons more difficult. Although mo-bility limitations led to a decrease in the number of disappearances, they did not stop completely and search teams had to adapt to the new scenario that prevent-ed, for example, the participation of volunteers. For these reasons, it was decided to implement a tool that has been in development for years, based on the Collab-oration Agreement signed in 2015 between the Servicio de Prevención y Extinción de Incendios de la Diputación Provincial de Zaragoza (SPEI-DPZ) and the Uni-versity of Zaragoza. The tool is called Virtual Cloud Search and Rescue (VC-SAR) and is still under development by the authors of this communication. The following is a basic description of the tool and how it was applied in a real case, in which a missing person was being searched. The device used made it possible to obtain about 5000 images of 44.7 megapixels, covering an area of over 2000 hectares. Thanks to the searches carried out, more than 100 pieces of evidence were found over the course of four days, which could be collected for on-site in-vestigation by the Navarra Fire Service. All this was possible thanks to the collab-oration of 5 different fire departments, belonging to three provinces, making pos-sible the participation of a total of 52 searchers from different locations. Keywords: Graphical tools; Aerial images; Search and rescue; Drones

UAV PHOTOGRAMMETRY FOR RESILIENCE MANAGEMENT IN RECONSTRUCTION PLAN OF URBAN HISTORICAL CENTRES AFTER SEISMIC EVENTS. A CASE STUDY

In the last decades, the UAV photogrammetry has been widely employed to obtain a complete and metric survey in different fields, especially when high resolution, speed of execution and safety are required. It is widely used in the construction sector and an interesting research field is their use to support the historical centres urban renewal projects, especially in post-earthquake reconstruction. In fact, the establishment of a construction site involves several intrinsic criticalities linked to the nature of the context, and especially in a post-earthquake scenario, additional problems arise beyond these critical elements. These conditions affect the preservation of historical centres, planned conservation, risk and resilience management. For this reason, it is necessary to develop innovative methodologies and strategy to plan interventions and to manage the construction sites in the historical centre after an earthquake.The use of UAV photogrammetry is a tool to support this activity in this field because it allows obtaining a complete and a high-resolution geometric survey of the areas to be reconstructed in a fast way and especially in total safety for the operators. For this reason, this study aims to illustrate a methodology that, starting from a series of preliminary surveys, supports the development of the program of reconstruction of a historic urban centre hit by an earthquake event. The aim of this research is to prevent problems, interferences and criticalities in order to increase the safety and rationality of the entire reconstruction process.</p

Mapping and classification of ecologically sensitive marine habitats using unmanned aerial vehicle (UAV) imagery and object-based image analysis (OBIA)

Nowadays, emerging technologies, such as long-range transmitters, increasingly miniaturized components for positioning, and enhanced imaging sensors, have led to an upsurge in the availability of new ecological applications for remote sensing based on unmanned aerial vehicles (UAVs), sometimes referred to as “drones”. In fact, structure-from-motion (SfM) photogrammetry coupled with imagery acquired by UAVs offers a rapid and inexpensive tool to produce high-resolution orthomosaics, giving ecologists a new way for responsive, timely, and cost-effective monitoring of ecological processes. Here, we adopted a lightweight quadcopter as an aerial survey tool and object-based image analysis (OBIA) workflow to demonstrate the strength of such methods in producing very high spatial resolution maps of sensitive marine habitats. Therefore, three different coastal environments were mapped using the autonomous flight capability of a lightweight UAV equipped with a fully stabilized consumer-grade RGB digital camera. In particular we investigated a Posidonia oceanica seagrass meadow, a rocky coast with nurseries for juvenile fish, and two sandy areas showing biogenic reefs of Sabelleria alveolata. We adopted, for the first time, UAV-based raster thematic maps of these key coastal habitats, produced after OBIA classification, as a new method for fine-scale, low-cost, and time saving characterization of sensitive marine environments which may lead to a more effective and efficient monitoring and management of natural resource

Use of UAS for the conservation of historical buildings in case of emergencies

The task of conservation and management of cultural heritage is quite central in Italy, which lists a high number of beautiful architectures. A quick and precise survey may be requested in case of calamity. In the present paper, the most commonly used survey techniques are discussed, focusing on their applications for the conservation of the artistic heritage in case of emergency. Particular attention is given to Unmanned Aerial Systems (UAS) photogrammetry and its potentiality in obtaining good results in terms of speed, cheapness, precision and accuracy, assuring at the same time the safety of the operators in critical situations (e.g. natural disasters). A case study, realized at the Castle of Casalbagliano (Alessandria, Italy), is discussed. Different image block configurations and acquisition geometries (nadiral and oblique images) have been exploited, with the aim of defining useful guidelines for emergencies UAS survey of partially collapsed structures. An application to a significative case study is introduced

Innovative Tools For Planning, Analysis, and Management of UAV Photogrammetric Surveys

The Unmanned Aerial System (UAV) is widely used in the photogrammetric surveys both for structures and small areas. The geomatics approach, for the several applications where the 3D modeling is required, focuses the attention on the metric quality of the final products of the survey. As widely known, the quality of results derives from the quality of images acquisition phase, which needs an accurate planning phase. Actually, the planning phase is typically managed using dedicated tools, adapted from the traditional aerial-photogrammetric flight plan. Unfortunately, UAV flight has features completely different from the traditional one, hence the use of UAV for photogrammetric applications today requires a growth in the planning knowledge. The basic idea of the present research work is to provide a tool for planning a photogrammetric survey with UAV, called \u201cUnmanned Photogrammetric Office\u201d (U.Ph.O.), that considers the morphology of the object, the effective visibility of its surface, in the respect of the metric precisions. The usual planning tools require the classical parameters of a photogrammetric planning: flight distance from the surface, images overlaps and geometric parameters of the camera. The created \u201cOffice suite\u201d U.Ph.O. allows a realistic planning of a photogrammetric survey, requiring additionally an approximate knowledge of the Digital Surface Model (DSM) and the attitude parameters, potentially changing along the route. The planning products will be the realistic overlapping of the images, the Ground Sample Distance (GSD) and the precision on each pixel taking into account the real geometry. The different tested procedures, the solution proposed to estimates the realistic precisions in the particular case of UAV surveys and the obtained results, are described in this thesis work, with an overview on the recently development of UAV surveys and technologies related to them

Active Faulting in the Northern Walker Lane and Post-Earthquake Reconnaissance in the Central Walker Lane, Nevada and Eastern California

The Walker Lane is a region of diverse tectonic activity situated along the Pacific-North American plate boundary. Unmapped and under characterized faults within the northern Walker Lane are associated with large uncertainties in the location and frequency of potential earthquakes in the greater Reno, Nevada metropolitan area. Mapping of primary and secondary earthquake features in post-event studies help understand the location of faulting and amount of damage associated with earthquakes in the central Walker Lane. Two fault systems in the northern Walker Lane are the Petersen Mountain fault located in the North Valleys region of Reno, and the Bonham Ranch fault in the Smoke Creek Desert of Pleistocene Lake Lahontan in the northern Walker Lane. A paleoseismic trench was excavated across the Petersen Mountain fault to document evidence for faulting and determine the timing of earthquake events. Optically stimulated luminescence dating methods were applied to faulted alluvial fan deposits exposed in the trench. For the Bonham Ranch fault, Uncrewed Aerial Vehicle (UAV) flight surveys were conducted in three locations to investigate differences between topographic scarps formed by tectonic displacement and shoreline processes. Cross cutting relations between the different scarp types combined with stratigraphic observations from outcrops were used to assess the timing of tectonic displacement across the fault. Additionally, UAV surveys were conducted during post-earthquake rapid response reconnaissance in the central Walker Lane immediately following the 15 May 2020 M6.4 Monte Cristo, Nevada and 8 July 2021 M6.0 Antelope Valley, California earthquakes. The drone flights assisted ground crews in determining where to look for surface rupture, earthquake secondary effects, and associated damage. These data provided insight into the amount and style of surface deformation immediately following the earthquake events, and the locations of faulting in the central Walker Lane. These studies help answer questions pertaining to the locations and effects of earthquakes in these regions. By incorporating UAV technology into tectonic studies, hi-res aerial images for mapping and Structure From Motion models can be created, and result in a permanent archive of post-earthquake surface damage as well as provide means to measure paleo and modern surface rupture offsets applicable to seismic hazard characterization