Appraisal of digital terrain elevation data for low-altitude flight

The use of terrain elevation databases in advanced guidance and navigation systems has greatly expanded. However, the limitations and accuracies of these databases must be considered and established prior to safe system flight evaluation. A simple approach to quantify reasonable flight limits is presented and evaluated for a helicopter guidance system dependent on a terrain database. The flight test evaluated involved a helicopter equipped with a Global Positioning System (GPS) receiver and radar altimeter, and a ground station GPS receiver which provided improved helicopter positioning. The precision navigation and radar altimeter data was acquired while flying low-altitude missions in south-central Pennsylvania. The aircraft-determined terrain elevations were compared with the terrain predicted by the Defense Mapping Agency (DMA) Level 1 terrain elevation data for the same area. The results suggest a safe set clearance altitude of 220 ft for flight testing of a DMA-based guidance avionic in the same area

Evaluation of flight efficiency for Stockholm Arlanda Airport using OpenSky Network data

Identification of causes of the delays within transition airspace is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Services: without knowing the current performance levels, it is difficult to identify which areas could be improved. Inefficient vertical profiles within TMA and deviations from the optimal flight paths due to bad weather conditions are the main sources of performance decline. In this work, we analyse punctuality and vertical efficiency of Stockholm Arlanda airport arrivals, and seek to quantify the fuel consumption impact associated with the inefficient vertical flight profiles within the Terminal Maneuvering Area (TMA). We use Opensky Network data for evaluation of the Stockholm Arlanda airport performance, comparing it to the DDR2 data provided by Eurocontol, outlining the advantages and disadvantages of both.Peer ReviewedPostprint (author's final draft

Development and demonstration of an on-board mission planner for helicopters

Mission management tasks can be distributed within a planning hierarchy, where each level of the hierarchy addresses a scope of action, and associated time scale or planning horizon, and requirements for plan generation response time. The current work is focused on the far-field planning subproblem, with a scope and planning horizon encompassing the entire mission and with a response time required to be about two minutes. The far-feld planning problem is posed as a constrained optimization problem and algorithms and structural organizations are proposed for the solution. Algorithms are implemented in a developmental environment, and performance is assessed with respect to optimality and feasibility for the intended application and in comparison with alternative algorithms. This is done for the three major components of far-field planning: goal planning, waypoint path planning, and timeline management. It appears feasible to meet performance requirements on a 10 Mips flyable processor (dedicated to far-field planning) using a heuristically-guided simulated annealing technique for the goal planner, a modified A* search for the waypoint path planner, and a speed scheduling technique developed for this project

4DT generator and guidance system

This thesis describes a 4D Trajectories Generator and Guidance system. 4D trajectory is a concept that will improve the capacity, efficiency and safety of airspace. First a 4D trajectories synthetizer design is proposed. A flight plan composed by a set of waypoints, aircraft dynamics model and a set of limits and constraints are assembled into an optimal control problem. Optimal solution is found by making use of an optimal control solver which uses pseudo spectral parametrization together with a generic nonlinear programming solver. A 4D Trajectories generator is implemented as a stand-alone application and combined with a graphic user interface to give rise to 4D Trajectories Research Software (4DT RS) capable to generate, compare and test optimal trajectories. A basic Tracking & Guidance system with proportional navigation concept is developed. The system is implemented as a complementary module for the 4D trajectories research software. Simulation tests have been carried out to demonstrate the functionalities and capabilities of the 4DT RS software and guidance system. Tests cases are based on fuel and time optimization on a high-traffic commercial route. A standard departure procedure is optimized in order to reduce the noise perceived by village’s population situated near airport. The tracking & guidance module is tested with a commercial flight simulator for demonstrating the performance of the optimal trajectories generated by the 4DT RS software

Visual 3-D SLAM from UAVs

The aim of the paper is to present, test and discuss the implementation of Visual SLAM techniques to images taken from Unmanned Aerial Vehicles (UAVs) outdoors, in partially structured environments. Every issue of the whole process is discussed in order to obtain more accurate localization and mapping from UAVs flights. Firstly, the issues related to the visual features of objects in the scene, their distance to the UAV, and the related image acquisition system and their calibration are evaluated for improving the whole process. Other important, considered issues are related to the image processing techniques, such as interest point detection, the matching procedure and the scaling factor. The whole system has been tested using the COLIBRI mini UAV in partially structured environments. The results that have been obtained for localization, tested against the GPS information of the flights, show that Visual SLAM delivers reliable localization and mapping that makes it suitable for some outdoors applications when flying UAVs

Autonomous flight and remote site landing guidance research for helicopters

Automated low-altitude flight and landing in remote areas within a civilian environment are investigated, where initial cost, ongoing maintenance costs, and system productivity are important considerations. An approach has been taken which has: (1) utilized those technologies developed for military applications which are directly transferable to a civilian mission; (2) exploited and developed technology areas where new methods or concepts are required; and (3) undertaken research with the potential to lead to innovative methods or concepts required to achieve a manual and fully automatic remote area low-altitude and landing capability. The project has resulted in a definition of system operational concept that includes a sensor subsystem, a sensor fusion/feature extraction capability, and a guidance and control law concept. These subsystem concepts have been developed to sufficient depth to enable further exploration within the NASA simulation environment, and to support programs leading to the flight test

ATM Performance Assessment of Minimum Climate Impact Trajectories in the European Airspace

Nowadays global warming represents an inescapable problem for human being life and entire globe. Nations from all around the planet are aware of the so called greenhouse gas emission that they are taking measurements in order to reduce the environmental impact. At the beginning, it was considered CO2 as the key agent, later emission reduction was focused on NOx. Currently, scientists state that persistent contrails have a nonnegligible impact in global warming. This thesis present a study were ATM performance parameters are studied, such as fuel consumption, confl ict, number of aircraft movements, flight time. In order to perform the analysis, four air traffic fl ow scenarios have been designed and simulated with TAAM, which is is a software developed by the Jeppesen Boing Company being capable of modelling air traffic and airspace. The four case studies correspond to the same low traffic day where horizontal profiles are computed as orthodromic routes between each origin and destination. The simulated scenarios are the following: Flight Plan Case (actual navigation procedure), Aircraft Ceiling Case (cruise FL at constant operational ceiling), Minimum Climate Impact Case (prevents contrail formation by fl ying at lower FL) and Optimal Profile Case (maximizes the position altitude by fly ing at continuously climbing at cruise phase).Ingeniería Aeroespacia

Novel ATM and avionic systems for environmentally sustainable aviation

Large-scale air transport modernisation initiatives including the Single European Sky Air Traffic Management Research (SESAR), Next Generation Air Transportation System (NextGen) and Clean Sky Joint Technology Initiative for Aeronautics and Air Transport aim to improve the operational efficiency, safety and environmental sustainability of aviation. Scientific advances in Air Transport Management (ATM) and avionic systems are required to achieve the ambitious goals set by national and international aviation organisations. This paper presents the recent advances in ATM and avionic system concepts, integrated architectures and trajectory generation algorithms, to be adopted in Next Generation Avionics Flight Management Systems (NG-FMS) and ground-based 4-Dimensional Trajectory Planning, Negotiation and Validation (4-PNV) systems. Current research efforts are focussed on the development of NG-FMS and 4-PNV systems for Four Dimensional (4D) Trajectory/Intent Based Operations (TBO/IBO), enabling automated negotiation and validation of aircraft intents and thus alleviating the workload of operators. After describing the NG-FMS/4PNV concept of operations, the overall system architecture and the key mathematical models describing the 4DT optimisation algorithms are introduced. Simulation case studies utilising realistic operational scenarios highlight the generation and optimisation of a family of 4DT intents by the NG-FMS corresponding to a set of performance weightings agreed between Air Navigation Service Providers (ANSP) and Airline Operation Centres (AOC). The savings on time, fuel burn and gaseous emissions (CO2 and NOx) associated with the globally optimal 4DT intents are presented. The developed optimisation and negotiation/validation loops meet the timeframe requirements of typical online tactical routing/rerouting tasks

Architecture and Information Requirements to Assess and Predict Flight Safety Risks During Highly Autonomous Urban Flight Operations

As aviation adopts new and increasingly complex operational paradigms, vehicle types, and technologies to broaden airspace capability and efficiency, maintaining a safe system will require recognition and timely mitigation of new safety issues as they emerge and before significant consequences occur. A shift toward a more predictive risk mitigation capability becomes critical to meet this challenge. In-time safety assurance comprises monitoring, assessment, and mitigation functions that proactively reduce risk in complex operational environments where the interplay of hazards may not be known (and therefore not accounted for) during design. These functions can also help to understand and predict emergent effects caused by the increased use of automation or autonomous functions that may exhibit unexpected non-deterministic behaviors. The envisioned monitoring and assessment functions can look for precursors, anomalies, and trends (PATs) by applying model-based and data-driven methods. Outputs would then drive downstream mitigation(s) if needed to reduce risk. These mitigations may be accomplished using traditional design revision processes or via operational (and sometimes automated) mechanisms. The latter refers to the in-time aspect of the system concept. This report comprises architecture and information requirements and considerations toward enabling such a capability within the domain of low altitude highly autonomous urban flight operations. This domain may span, for example, public-use surveillance missions flown by small unmanned aircraft (e.g., infrastructure inspection, facility management, emergency response, law enforcement, and/or security) to transportation missions flown by larger aircraft that may carry passengers or deliver products. Caveat: Any stated requirements in this report should be considered initial requirements that are intended to drive research and development (R&D). These initial requirements are likely to evolve based on R&D findings, refinement of operational concepts, industry advances, and new industry or regulatory policies or standards related to safety assurance