DESTinationRAIL, a Decision Support Tool for Rail Infrastructure Managers, is a 3 year project funded by the EU Horizon 2020 initiative. The project started in May 2015 and has a consortium of 15 members, full details of the project and its members can be found on the project website www.destinationrail.eu
The aim of DESTination RAIL is to provide solutions for a number of problems faced by EU infrastructure managers using novel techniques for identifying, analysing and remediating critical rail infrastructure leading to a reduction in costs of up to 20% along with improved reliability of the asset leading to improved train performance. These solutions will be implemented using a decision support tool, which allows rail infrastructure managers to make rational investment choices, based on reliable data.
The European rail Infrastructure network is aging with in some cases very poor records of the construction of the asset as many of the assets were constructed more than 150 years ago, whilst at the same time there is huge pressure on maintenance and investment budgets with available investment needing to be targeted on the key assets at risk.
The objective of the project (safer, reliable and efficient rail infrastructure) will be achieved through a holistic management tool based on the FACT (Find, Analyse, Classify, Treat) principle as shown in figure 1.
Find – Improved techniques for the assessment of existing assets are currently being developed using modern off the shelf technology.
Analyse – Advanced probabilistic models fed by performance statistics and using databases
controlled by an information management system will be used to determine the level of safety of individual assets.
Classify – The performance models will allow a step-change in risk assessment, moving from the current subjective (qualitative) basis to become fundamentally based on quantifiable data. A decision support tool will take risk ratings and assess the impact on the traffic flow and whole life cycle costs of the network.
Treat – Novel and innovative maintenance and construction techniques for treating rail infrastructure including tracks, earthworks and structures are being developed and assessed by the whole life cycle assessment model together with the impact on the traffic flow.
The aging of European rail Infrastructure network faces many problems regarding needs for assessment of its condition. A practice through which the railway managers make critical investment decisions relying mostly on a visual assessment is still present on global scale. For this, use of Unmanned Aerial Vehicles can be extremely helpful as evidenced by the increasing number of applications in this area of interest.
Further possible use of Unmanned Aerial Vehicles is in advanced engineering analysis through the formation of high resolution photos, orthophoto maps and 3D models.
An unmanned aerial vehicle (UAV), commonly known as a “drone” is an aircraft without a human pilot aboard. Drone proponents rather prefer that everyone use the term Unmanned Aerial System (UAS), in which “System” encompass the entirety of the vehicle that flies, the ground-based controller and different types of sensors that can be mounted on it. From all different types of drones currently available on market, two major types can be distinguished by construction: “Fixed wing” (Figure 1a) and “Rotary wing” (Figure 1b).
Fixed wing UAS are similar in design to aeroplanes. The simple design with one rigid wing across the top of the body allows this UAS high speeds and long flight distances. This type of drone is ideal for coverage of large areas, such as aerial mapping and surveillance applications. One of the features for this type of UAS is their ability to carry heavier payloads, meaning bigger and sometimes better sensors and cameras that can be used. They can efficiently glide through the sky thanks to the sleek structure, and having only one fixed wing drastically reduces the risk of mechanical failure. The maintenance and repair process for these units is often minimal, saving lot of time and money.
Rotary wing UAS, however, share more of their characteristics with manned helicopters. Rather than a continuous forward movement to generate airflow, these units rely on lift from the constant rotation of the rotor blades. There is no limit on how many blades an aircraft has, but the average is between one and eight. Those consisting of one rotor blade are known as helicopters, three blades are tricopters, four are quadcopters, and so on. It is the blades that provide rotary wing drones with the ability to move in any direction. Unlike fixed wing units, rotary wing units have the ability of vertical take off and landing, meaning they can be deployed from absolutely anywhere. The advantage is really seen when operation is required in a small space and the aircraft can lift from the spot, and their capacity to hover at the same position. These drones can move in any direction, hovering over important areas, collecting the most intricate data. It is this ability that makes them so well suited for inspections where precision maneuvering is critical to the operation – railroads, pipelines, power lines and bridges are all applications that would reap the benefits from rotary wing drones.
The new terminology UAS photogrammetry describes a photogrammetric measurement platform, which operates remotely controlled, semi-autonomously, or autonomously, without a pilot sitting in the vehicle. The platform can be equipped with a photogrammetric measurement system, including, but not limited to a small or medium size camera or video camera, thermal or infrared camera systems, airborne LiDAR system, or a combination of all (Figure 2).
Current standard UAS allows the registration and tracking of the position (like Global Positioning System – GPS or Inertial Navigation System – INS) and orientation of the implemented sensors in a local or global coordinate system. Accordingly, UAS photogrammetry can be understood as a new photogrammetric measurement tool. UAS photogrammetry opens various new applications in the close range domain, combining aerial and terrestrial photogrammetry, introducing new real time application and low-cost alternatives to the classical manned aerial photogrammetry, and also provides both a quick overview of a situation, as well as detailed area documentation. More details can be found on the website of the Journal of the Croatian Association of Civil Engineers http://www.casopis-gradjevinar.hr/.
Collection of 3D data by conventional surveying methods in special cases can be quite time-consuming, expensive and even dangerous for the field operator. As an example can be mentioned locations as steep slopes and cuts and locations where there are potential rockfalls, landslides or mudslides. Visual inspection of the terrain in such locations, just as geodetic data collection with classical methods can result in incomplete and insufficiently detailed display of the terrain, and thus jeopardize the secure communication of rail or road transport.
The use of drones in such locations can greatly complement, enhance and even completely replace the classical methods of mapping, determining the volume, cross-sections, contours and other parameters that are necessary for the remediation measures (Figure 3). Upon arrival at the terrain is not required to approach the hazardous location, but come to a safe proximity and send UAS (with a pre-programmed flight or manually guided) to collect the data needed for quality and correct visualization and field interpretation.
In order to create a three-dimensional model of a terrain or structure, a considerable number of photographs of the area must be taken, with longitudinal and transverse overlapping between the photographs. The principal objective of the computer program is to link these photographs into a single whole, and to generate a point cloud (Figure 4) using the following steps:
identify similarities between the photos,
1 derive the SfM (Structure from Motion) algorithm,
2 make geo-references,
3 finalise the process and make image changes as needed.
The point cloud and ortophoto map, which are fully measurable, can be used to define cross-sections (Figure 5) and calculate volumes (Figure 6) that can be transferred to CAD programs, which are readily used in most professions conducting mapping and design activities. More details can be found on the website of the Journal of the Croatian Association of Civil Engineers http://www.casopis-gradjevinar.hr/.
The use of unmanned aerial vehicles presents a number of advantages the most notable being the possibility of adjustment to various needs of the users, possibility of analysing and surveying hardly accessible areas and, in case of breakdown or fall of the unmanned device, the life of the pilot is not put to danger. Some possible drawbacks are high production and maintenance costs, high costs in case of fall or breakdown of the flying device, and the fact that it can’t be used in adverse weather conditions. In addition, the error in operation of the unmanned device can result in the fall which, in addition to damage to objects on the ground, can result in fatal accidents. Good quality photogrammetric surveys can presently be made by low-budget UAS equipped with cameras. Positive features such as great flexibility with regard to accuracy of survey results, and high level of efficiency and automation, point to the selection of the photogrammetric method, which has been standardly used for a number of years.
by Marijan Car, Danijela Juric Kacunic
University of Zagreb, Faculty of Civil Engineering, Croatia
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