Formation of unmanned aircraft trajectory when flying around prohibited areas

Considered the problem of flying over restricted areas by an unmanned aerial vehicle (UAV), which have various shapes and restrictions, set on the basis of the international airspace classification system for aviation in accordance with the Chicago Convention and the recommended principles for the formation of forbidden zones, rules for creating a flight route along forbidden zones and actions in case of border violations of restricted areas. The problem of analytical synthesis of the control acceleration of an unmanned aerial vehicle (UAV) is solved during its flight along a route passing along the boundaries of the forbidden zone of a given shape, along a given trajectory, which consists of subsequent segments located at the same height relative to the earth’s surface, in a given coordinate system. The optimal control synthesis problem is solved as an analytical definition of the optimal control of a linear non-stationary system based on the quadratic quality functional. A mathematical model of UAV motion in the horizontal plane is proposed, in the form of a system of ordinary differential equations in the Cauchy form. A law for measuring the control acceleration of the UAV’s center of mass is obtained on the basis of specifying the minimized quality functional and the corresponding constraints, which is a feature of the considered method of solving the problem. The proposed quality functional takes into account the parameters of coordinates and speed of the UAV, which correspond to the given points in the airspace, which characterize the necessary trajectory for flying around the restricted area. The derived mathematical dependences make it possible to implement them on board a UAV and minimize energy costs when guiding a UAV moving through specified points in space. Computer modeling of the derived analytical results, mathematical dependencies representing the optimal trajectory of the UAV flight along the boundaries of the forbidden zone, as well as the corresponding processes of changing the control acceleration and speed of the UAV movement was carried out, which made it possible to draw conclusions about the efficiency of the proposed method and the feasibility of its further use as a basis. for the initial stage of the synthesis of the UAV control system.

Stimulus-dependent orientation strategies in monarch butterflies

Insects are well-known for their ability to keep track of their heading direction based on a combination of skylight cues and visual landmarks. This allows them to navigate back to their nest, disperse throughout unfamiliar environments, as well as migrate over large distances between their breeding and non-breeding habitats. The monarch butterfly (Danaus plexippus) for instance is known for its annual southward migration from North America to certain trees in Central Mexico. To maintain a constant flight route, these butterflies use a time-compensated sun compass for orientation which is processed in a region in the brain, termed the central complex. However, to successfully complete their journey, the butterflies' brain must generate a multitude of orientation strategies, allowing them to dynamically switch from sun-compass orientation to a tactic behavior toward a certain target. To study if monarch butterflies exhibit different orientation modes and if they can switch between them, we observed the orientation behavior of tethered flying butterflies in a flight simulator while presenting different visual cues to them. We found that the butterflies' behavior depended on the presented visual stimulus. Thus, while a dark stripe was used for flight stabilization, a bright stripe was fixated by the butterflies in their frontal visual field. If we replaced a bright stripe by a simulated sun stimulus, the butterflies switched their orientation behavior and exhibited compass orientation. Taken together, our data show that monarch butterflies rely on and switch between different orientation modes, allowing them to adjust orientation to the actual behavioral demands of the animal.

Qualitative Assessment of General Aviation Pilots’ Perceptions of Preflight Weather Briefings

Prior to departing on a flight, General Aviation pilots complete a preflight planning process to ensure the safety of their flight. One aspect of the preflight planning process is obtaining a briefing on the weather conditions that the pilot might encounter along their flight route. Traditionally pilots have utilized a phone-in service, run by Flight Services, to aid in their assessment of weather conditions; however, research indicates that pilots are increasingly reliant on conducting self- briefing using online resources. The purpose of this study is to determine pilot perceptions of obtaining a phone-in brief in comparison to self-briefing.

Artificial Immune Algorithm-based Airplane Path Planning under Complicated Environment

This paper mainly studies the flight route planning in complex and uncertain environments. The improved artificial immune algorithm is used to complete the flight route planning in different complex environments. The experimental results show that the improved artificial immune algorithm has a higher success rate of route planning than the common genetic algorithm in complex environments; therefore, it also shows that this method has better adaptability in complex environment

Regular graph-based free route flight planning approach

Purpose The purpose of this study is to provide an alternative graph-based airspace model for more effective free-route flight planning. Design/methodology/approach Based on graph theory and available data sets describing airspace, as well as weather phenomena, a new FRA model is proposed. The model is applied for near to optimal flight route finding. The software tool developed during the study and complexity analysis proved the applicability and timed effectivity of the flight planning approach. Findings The sparse bidirectional graph with edges connecting only (geographically) closest neighbours can naturally model local airspace and weather phenomena. It can be naturally applied to effective near to optimal flight route planning. Research limitations/implications Practical results were acquired for one country airspace model. Practical implications More efficient and applicable flight planning methodology was introduced. Social implications Aircraft following the new routes will fly shorter trajectories, which positively influence on the natural environment, flight time and fuel consumption. Originality/value The airspace model proposed is based on standard mathematical backgrounds. However, it includes the original airspace and weather mapping idea, as well as it enables to shorten flight planning computations.

Evaluation of flight conditions at tropopause level

High-quality organization of meteorological support along the flight routes, increasing its efficiency depends on many factors. These factors include the moderate and high intensity turbulence observed in the middle and upper flight echelons, icing, jet streams, volcanic ash clouds and their distribution areas, tropopause level, its altitude, and others. In the pre-flight preparation phase, the meteorological body provides meteorological support for all types of domestic and international flights planned in the middle and upper troposphere. The organization of flight efficiency and economic profitability depends on the high-quality forecast of the above-mentioned meteorological factors. The article analyzes the characteristics of weather conditions that affect flights in the middle and upper troposphere. The main recommendations and requirements of Annex 3 (ANEX 3) and its amendments (Amendment 79), ICAO's guidelines for meteorological support for international air navigation, are relevant to many of the issues discussed in this article. Key words: turbulence, jet stream, volcanic ash, aircraft, tropopause, aviation, flight echelon, pressure, wind, temperature, meteorological support, flight route

Looking for Agency in Transnational Refugee Trajectories during the Second World War - Eric T. Jennings. Escape from Vichy: The Refugee Exodus to the French Caribbean. Cambridge, Mass.: Harvard University Press, 2018. 308 pages. ISBN: 9780674983380, $36. - Megan Koreman. The Escape Line: How the Ordinary Heroes of Dutch-Paris Resisted the Nazi Occupation of Western Europe. New York: Oxford University Press, 2018. 410 pages. 9780190662271, $29,95. - Joanna Newman. Nearly the New World: The British West Indies and the Flight from Nazism, 1933–1945. New York: Berghahn Books, 2019. 306 pages. 9781789206494, $29,95.

The authors of three recent monographs, The Escape Line, Escape from Vichy, and Nearly the New World, highlight in particular the relevance of transnational refugee and resistance networks. These books shed new light on the trajectories of refugees through war-torn Europe and their routes out of it. Megan Koreman displays in The Escape Line the relevance of researching one line of resistance functioning in several countries and thereby shifts from the common nationalistic approach in resistance research. In Escape from Vichy Eric Jennings researches the government-endorsed flight route between Marseille and Martinique and explores the lasting impact of encounters between refugees and Caribbean Negritude thinkers. Joanna Newman explores the mainly Jewish refugees who found shelter in the British West Indies, with a focus on the role of aid organisations in this flight.

Estimate of economic impact of atmospheric radiation storm associated with solar energetic particle events on aircraft operations

A solar energetic particle (SEP) event generates a shower of secondary generated particles in the Earth’s atmosphere down to lower altitudes to cause an atmospheric radiation storm (ARS). The high-energy secondary particles cause additional radiation dose at altitudes where aircraft flies. The space weather information provided by the International Civil Aviation Organization (ICAO) designated space weather centers includes advisories on the solar radiation storm. The Warning System for AVIation Exposure to Solar energetic particle (WASAVIES), we can estimate the effective dose rate (EDR) along the flight path of the aircraft. However, it has not been well established how the operators of aircraft should react with the space weather advisories on the solar radiation storm. By using a flight trajectory generation algorithm and the global EDR distribution, the economic impacts of ARS associated with SEP events on aircraft operation, namely the flight path length, flight time, and fuel consumption, are estimated. The conditions of the peak of the ARS event on 20 January 2005 are used. The economic impacts for a flight route from New York, US to Tokyo, Japan, are estimated with constraints in flight routes to avoid the hazard of radiation and compared with those of the reference case without the ARS effects. The fuel consumption is shown to increase by 39–69 tons (33–58%) for a twin-engine, wide-body jet passenger aircraft, when a constraint is imposed on the flight altitude only. When the constraints are set on the aircraft altitude and the latitude, the flight time and the fuel consumption are both increased by 2.2–2.8 h (17–20%) and 32–48 tons (27–41%), respectively. If the ARS event duration is limited for 3 h, the increase in the fuel consumption is about 7.6–14 tons (6.4–12%). This economic impact may be reduced, if the space weather nowcast and forecast for the ARS and an optimal flight trajectory generation algorithm are used together. Setting more flexible constraints on the flight route and generating optimal flight trajectories with minimal economic impacts by fully utilizing the global EDR distribution is the next step.

Bats seek refuge in cluttered environment when exposed to white and red lights at night

Background Artificial light at night is recognized as an increasing threat to biodiversity. However, information on the way highly mobile taxa such as bats spatially respond to light is limited. Following the hypothesis of a behavioural adaptation to the perceived risks of predation, we hypothesised that bats should avoid lit areas by shifting their flight route to less exposed conditions. Methods Using 3D acoustic localization at four experimentally illuminated sites, we studied how the distance to streetlights emitting white and red light affected the Probability of bats Flying Inside the Forest (PFIF) versus along the forest edge. Results We show that open-, edge-, and narrow-space foraging bats strongly change flight patterns by increasing PFIF when getting closer to white and red streetlights placed in the forest edge. These behavioural changes occurred mainly on the streetlight side where light was directed. Conclusions The results show that bats cope with light exposure by actively seeking refuge in cluttered environment, potentially due to involved predation risks. This is a clear indication that bats make use of landscape structures when reacting to light, and shows the potential of vegetation and streetlight orientation in mitigating effects of light. The study nevertheless calls for preserving darkness as the most efficient way.