Flight Direction Research Articles

Research on the Migration Law of Hornet Based on Machine Learning

Bumblebees prey on European honeybees, invade and destroy their nests, severely disrupting the local ecological balance and economic stability. In order to study the specific impact of the bumblebee, this paper establishes a gray Gaussian prediction verification model based on machine learning methods, which is used to predict the flight direction of the wasp through gray correlation analysis, and the Gaussian process regression model is used to determine the flight range; Through the discussion of negative ID, the Yolo model is used for feature extraction, the resnet101 model is used for classification prediction, and then a more summarized dimension is selected to find the corresponding bee species.

Electron multiplication and avalanching in nanovoids at the initial stage of nanosecond discharge in liquid water

This work presents a study on electron multiplication in cylindrical nanovoids formed in liquid water due to strong pulsed external electric fields. The state-of-the-art simulation toolkit Geant4-DNA is used to describe electron interactions in liquid water. Scaling laws for electron propagation are introduced, concluding that the product of the electric field strength E and the cavity radius R is a suitable parameter to compare simulation results for different values of E and R, and 1/R scaling is proposed for space and time variables. It is shown that the electron avalanche can grow inside of the nanovoid if E ⋅ R > 19.4 eV. The avalanche growth is fed by the emission of the secondary electrons from the surface of the nanovoid. This electron avalanche can also provide a higher total ionization yield along the nanovoid than the simple direct flight of electrons through the nanovoid length. Characteristic electron multiplication timescale and avalanche velocity are determined. Multiplication timescale is shown to be of the order of 1 ps or shorter for electron-multiplying conditions. The velocity of the electron avalanche is about 2.8 × 106 m s−1. The multiplication timescale and the avalanche velocity are consistent with recent experimental observations on nanosecond discharge initiation in liquid water.

Repeated training of homing pigeons reveals age-dependent idiosyncrasy and visual landmark use

Recent research into the navigational strategies of homing pigeons, Columba livia , in the familiar area has highlighted the phenomenon of route fidelity: birds forming idiosyncratic flight paths to which they are loyal over multiple releases from the same site, and even returning to this path when released from a nearby unfamiliar location. Such results highlight the potential importance of visual landmark cues in the homing process. However, not all birds have been found to produce idiosyncratic routes or show this route-joining behaviour. Here we used birds with and without flight experience to study the formation of idiosyncratic routes when released repeatedly from a single location, followed by two off-route releases with differing topography to see how flight experience and local landmark features can influence navigational strategy in the familiar area. We found that, over the course of 20 sequential releases, birds with greater flight experience tended to form idiosyncratic routes whereas less experienced birds did not show this tendency. When released from nearby sites (from which the birds had not previously been released), a range of navigational strategies were seen, including flying parallel to the learned route (suggestive of a learned compass direction), a direct flight path towards home (again indicative of compass use), rejoining the learned route and following the coastline. These latter strategies are suggestive of landmark usage. Analysis using time lag embedding was also used to assess the off-route releases, and the short-term correlation dimension values produced were also indicative of strategies using one or two factors (landmarks, compass or a combination of these two). Individual birds often showed different strategies at different sites, suggesting that the use of different navigational cues is highly flexible and situationally dependent. • Birds with greater flight experience form idiosyncratic routes more readily. • Multiple homing strategies occur when released close to a familiar site. • Age and site-specific biases occurred in which strategies were used. • Flexibility within individuals was seen in terms of strategy choice and cue use.

Mapping marine debris encountered by albatrosses tracked over oceanic waters

Anthropogenic marine debris is a threat to marine organisms. Understanding how this debris spatially distributes at sea and may become associated with marine wildlife are key steps to tackle this current issue. Using bird-borne GPS- and video-loggers on 13 black-footed albatrosses Phoebastria nigripes breeding in Torishima, Japan, we examined the distribution of large floating debris in the Kuroshio Current area, western North Pacific. A total of 16 floating debris, including styrofoam (n = 4), plastic pieces (n = 3), plastic sheet (n = 1), fishery-related items (rope or netting, n = 4), and unidentified debris (n = 4), were recorded across the 9003 km covered by nine birds. The debris was concentrated in the southern area of the Kuroshio Current, where the surface current was weak, and the albatrosses were foraging. The albatrosses displayed changes in flight direction towards the debris when at a mean distance of 4.9 km, similarly to when approaching prey, and one bird was observed pecking at a plastic sheet; indicating that albatrosses actively interacted with the debris. This paper shows the usefulness of studying wide-ranging marine predators through the use of combined biologging tools, and highlights areas with increased risk of debris exposure and behavioral responses to debris items.

A Direct Flight to Revolution: Maududi, Divine Sovereignty, and the 1979-Moment in Iran

AbstractThis article explores the engagement of the Pakistani Jamaʿat-i Islami (JI) with the Iranian Revolution. I argue that the Islamist JI was drawn to the events because it reflected a core concern and signature idea of Abu ’l-Aʿla Maududi, namely to establish the sovereignty of God (hakimiyya) on earth. My analysis of various travelogues and JI publications from the 1980s demonstrates that JI observers were deeply familiar with internal revolutionary dynamics and Iran's Shiʿi identity. The prospect of seeing a proper Islamic system in action, with potentially global consequences for their cause, initially crowded out any sectarian concerns for the JI. At the same time, certain JI leaders began to voice criticism of what they perceived as rash revolutionary policies that differed from Maududi's careful, irenic understanding of a proper Islamic revolution. They also took note of sectarian messages that damaged Iran's ecumenical outreach. It was, however, the more general geopolitical climate in the Middle East and South Asia which forced the JI to publicly downplay its ties with Iran. By the late 1980s, being accused of harbouring affinities for the ‘deviant Islam’ of Shiʿism was a charge that had to be avoided at all costs in Pakistan and beyond.

Investigation of the Powder Aerosol Deposition Method Using Shadowgraph Imaging.

The powder aerosol deposition method (PAD) is a vacuum-based spray coating technology. It allows for production of highly dense coatings at room temperature, especially of brittle-breaking materials. This yields new options for coating substrate materials that even melt at low temperatures. The film formation mechanism is called room temperature impact consolidation (RTIC). The occurrence of this mechanism is strongly linked to the gas jet used in the process. The velocity and direction of the particles in the gas jet forming between the nozzle orifice and the substrate are the main factors influencing the quality of the coating. This dependency aimed to be elaborated with a measurement setup and coating experiments and is shown in this work. We investigated the gas jet formation using a shadow optical imaging system. Regions of different gas density are visualized by this technique. Several parameter sets, in particular gas flow rates and chamber pressures, were investigated. In addition, coatings were produced on glass substrates with the same parameters. As a coating material, the superconducting ceramic-like magnesium diboride (MgB2) was chosen. A correlation between shadow images and thickness profiles of the coatings shows how the gas jet formation affects the uniformity of thickness. Shadow optical images provide valuable information on the flight direction of the particles and allow validation of simulation results.

Computational steady-thrust vector controlsupersonic secondary flow injection

This paper presents the Computational study of flow through the Rocket Nozzle in order to manoeuvre the Rocket by means of Supersonic Secondary Injection of Hot gases. Well-designed nozzles can accelerate these gases to speeds of thousands of meters per second. In addition to accelerating the gases, nozzles are often responsible for steering (or “vectoring”) the flow in order to control the rocket’s direction of flight. Due to continuous secondary injection of hot gases, the strong unsteady effects like Shear Layers, Intervention of Shockwaves with the Core fluid flow, Biased Wall Shear, etc., has to be studied precisely to appraise/evaluate the effectiveness of Nozzle contribution in role of steering the Rocket. Numerical Technique/Computational Analysis has been carried out to provide tons of insight about the meticulous behavior of Fluid particles while they interact with secondary flow. Comparative study on Supersonic Fluid Flow and the intervention of Secondary Injection of Hot gases has been carried at different angle of injection and at different injecting Pressure in order to find its optimum injection angle and optimum Injecting Pressure. It has been observed that Steering of Rocket drives well by Secondary Injection when its injecting angle becomes tangential to fluid flow direction and Injecting Pressure favors to steer the rocket when it increases its magnitude.

Phylogenetic Patterns in Mouth Posture and Echolocation Emission Behavior of Phyllostomid Bats

While phyllostomid bats show an impressive range of feeding habits, most of them emit highly similar echolocation calls. Due to the presence of an often prominent noseleaf, it has long been assumed that all phyllostomids emit echolocation calls exclusively through the nostrils rather than through the mouth. However, photo evidence documents also phyllostomid bats flying with an opened mouth. We hypothesized that all phyllostomid species emit echolocation calls only through the nostrils and therefore fly consistently with a closed mouth, and that observations of an open mouth should be a rare and random behavior among individuals and species. Using a high-speed camera and standardized conditions in a flight cage, we screened 40 phyllostomid species. Behavior varied distinctly among the species and mouth posture shows a significant phylogenetic signal. Bats of the frugivorous subfamilies Rhinophyllinae and Carolliinae, the nectarivorous subfamilies Glossophaginae and Lonchophyllinae, and the sanguivorous subfamily Desmodontinae all flew consistently with open mouths. So did the animalivorous subfamilies Glyphonycterinae, Micronycterinae and Phyllostominae, with the notable exception of species in the omnivorous genus Phyllostomus, which consistently flew with mouths closed. Bats from the frugivorous subfamily Stenodermatinae also flew exclusively with closed mouths with the single exception of the genus Sturnira, which is the sister clade to all other stenodermatine species. Further, head position angles differed significantly between bats echolocating with their mouth closed and those echolocating with their mouths opened, with closed-mouth phyllostomids pointing only the nostrils in the direction of flight and open-mouth phyllostomids pointing both the nostrils and mouth gape in the direction of flight. Ancestral trait reconstruction showed that the open mouth mode is the ancestral state within the Phyllostomidae. Based on the observed behavioral differences, we suggest that phyllostomid bats are not all nasal emitters as previously thought and discuss possible reasons. Further experiments, such as selectively obstructing sound emission through nostrils or mouth, respectively, will be necessary to clarify the actual source, plasticity and ecological relevance of sound emission of phyllostomid bats flying with their mouths open.

Phylogenetic Patterns in Mouth Posture and Echolocation Emission Behavior of Phyllostomid Bats

While phyllostomid bats show an impressive range of feeding habits, most of them emit highly similar echolocation calls. Due to the presence of an often prominent noseleaf, it has long been assumed that all phyllostomids emit echolocation calls exclusively through the nostrils rather than through the mouth. However, photo evidence documents also phyllostomid bats flying with an opened mouth. We hypothesized that all phyllostomid species emit echolocation calls only through the nostrils and therefore fly consistently with a closed mouth, and that observations of an open mouth should be a rare and random behavior among individuals and species. Using a high-speed camera and standardized conditions in a flight cage, we screened 40 phyllostomid species. Behavior varied distinctly among the species and mouth posture shows a significant phylogenetic signal. Bats of the frugivorous subfamilies Rhinophyllinae and Carolliinae, the nectarivorous subfamilies Glossophaginae and Lonchophyllinae, and the sanguivorous subfamily Desmodontinae all flew consistently with open mouths. So did the animalivorous subfamilies Glyphonycterinae, Micronycterinae and Phyllostominae, with the notable exception of species in the omnivorous genus Phyllostomus, which consistently flew with mouths closed. Bats from the frugivorous subfamily Stenodermatinae also flew exclusively with closed mouths with the single exception of the genus Sturnira, which is the sister clade to all other stenodermatine species. Further, head position angles differed significantly between bats echolocating with their mouth closed and those echolocating with their mouths opened, with closed-mouth phyllostomids pointing only the nostrils in the direction of flight and open-mouth phyllostomids pointing both the nostrils and mouth gape in the direction of flight. Ancestral trait reconstruction showed that the open mouth mode is the ancestral state within the Phyllostomidae. Based on the observed behavioral differences, we suggest that phyllostomid bats are not all nasal emitters as previously thought and discuss possible reasons. Further experiments, such as selectively obstructing sound emission through nostrils or mouth, respectively, will be necessary to clarify the actual source, plasticity and ecological relevance of sound emission of phyllostomid bats flying with their mouths open.

Efficient Quadcopter Flight Control Using Hybrid SSVEP + P300 Visual Brain Computer Interface

ABSTRACT The objective of this study was to assess the feasibility of hybrid SSVEP + P300 visual BCI systems for quad-copter flight control in physical world. Existing BCI-based quad-copter flight control has limitations of slow navigation, lower system accuracy, rigorous user training requirement and lesser number of independent control commands. So, there is need of hybrid BCI design that combines evoked SSVEP and P300 potentials to control flight direction of quad-copter movement. GUI design is developed such that user can effectively control quad-copter flight by gazing at visual stimuli buttons that produce SSVEP & P300 potentials simultaneously in human cortex. We compare the performance metrics of the proposed flight control systems with other existing BCI-based flight control as conventional SSVEP BCI and P300 BCI and commercially available keyboard flight control systems. Results proved that the proposed system outperforms the existing BCI-based flight control systems but has slightly lower performance efficiency than the commercial keyboard flight control systems. Further, the proposed quad-copter flight control system proved its suitability for patients with severe motor disabilities.

Real-Time Garbage Object Detection With Data Augmentation and Feature Fusion Using SUAV Low-Altitude Remote Sensing Images

Recently, a number of nature reserves have been shut down because of serious pollution from tourist garbage. Garbage monitoring in high-altitude natural reserves using small unmanned aerial vehicle (SUAV) remote sensing is an important and urgent need for environmental protection. In order to help cleaners to eliminate garbage more conveniently and quickly, a novel approach is proposed to detect scattered garbage regions in real time using low-altitude remote sensing videos captured by SUAVs. First, the high-resolution, low-altitude, multitemporal remote sensing images and videos containing scattered garbage were collected through SUAV and then proposed a data augmentation method to expand the training samples. Second, the Yolov4 detection network was used to classify the scattered garbage regions. Finally, the location of the object was roughly calculated according to the altitude, flight direction, global positioning system, and digital elevation model (DEM). Then, the garbage object was marked on the video, while the object location was marked on the map. Experimental results show that the proposed method achieves a mean accuracy of 91.34% and provides better performances on the real data set compared with state-of-the-art methods.

Autumn southward migration of dragonflies along the Baltic coast and the influence of weather on flight behaviour

Despite mass movements of insects being documented for decades, whether dragonflies migrate in Europe has not yet been experimentally tested. Similarly, little is known about the influence of weather on the movement decisions and intensity of dragonflies. Taking advantage of large movements of dragonflies along the Baltic Sea coast of Latvia, we investigated whether European dragonflies showed directed movements indicative of migratory behaviour and how weather influences their movements. First, we performed orientation tests with individual dragonflies of two commonly captured species, Aeshna mixta and Sympetrum vulgatum , to determine whether dragonflies showed directed flight and whether flight direction differed from wind direction. Both A. mixta and S. vulgatum displayed a uniform mean southward orientation, which differed from the prevailing overhead wind direction, indicating migratory behaviour. Second, we investigated the influence of weather conditions on the abundance of dragonflies captured. Differences in flight behaviour in relation to weather conditions were observed between A. mixta and the two smaller Sympetrum species ( S. vulgatum and S. sanguineum ). Generally, temperature, cloud cover and wind direction were the most important predictors for dragonfly abundance, with temperature positively, and cloud cover negatively, influencing abundance. Aeshna mixta appeared to select favourable tail winds (northerlies), whereas abundance of Sympetrum increased with more easterly winds. Our results provide important information on the influence of local weather conditions on the flight behaviour of dragonflies, as well as evidence of dragonfly migration along the Baltic coast. • Evidence for dragonfly migration along the Baltic coast in Europe. • Aeshna mixta and Sympetrum vulgatum show directed southward flight. • Temperature, cloud cover and wind direction predict migration intensity. • Migratory Aeshna and Sympetrum species respond differently to local weather. • The migrant hawker A. mixta selects for favourable tail winds.

Myofibrillar (Network) Structures in Skeletal Muscles: An Evolutionarily Conserved Adaptation?

Skeletal muscles play a central role in converting biological fuel to functional force via the contraction of myofibrils. Until recently, myofibrils were characterized as individual cylindrical structures that run parallel to each other along the length of the muscle cell. However, using nanoscale 3D imaging, our group demonstrated that the contractile apparatus of vertebrate muscle cells is comprised of a unified myofibrillar matrix in which myofibrils frequently connect to each other through branching and merging events. While this work established myofibrillar connectivity as a fundamental component of all striated muscle cell types in vertebrate models, including mice and humans, it is unknown whether myofibrillar connectivity is evolutionarily conserved across invertebrate models commonly used to investigate muscle cell biology. Here, we use 3-dimensional focused-ion beam electron microscopy (FIB-SEM) to evaluate myofibrillar ultrastructure in different striated muscle cell types from Drosophila melanogaster. All procedures were approved by the National Heart, Lung, and Blood Institute Animal Care and Use Committee and performed in accordance with the guidelines described in the Animal Care and Welfare Act (7 USC 2142 § 13). 3D reconstruction of myofibrillar structures revealed that, similar to vertebrates, the myofibrils within direct flight (DF), jump, and leg muscles of Drosophila link together to form highly connected myofibrillar networks. Alternatively, we found that myofibrils in indirect flight (IF) muscles do not connect to each other as each successive sarcomere was connected in series to form isolated myofibrils. Quantitative assessment of DF, jump, and leg muscles revealed that the frequency of sarcomere branching differs by muscle type with leg muscles exhibiting the highest branching compared to no branching in IF muscles (see Supporting Figures). The percentage of myofibrils within the field of view of our datasets with at least one branching sarcomere is as follows: 94 ± 4.2% (mean ± SE, 3 cells, 150 myofibrils, 690 sarcomeres) in leg muscles, 77 ± 5.0% (4 cells, 200 myofibrils, 1461 sarcomeres) in DF muscles, 50 ± 3.7% (3 cells, 150 myofibrils, 1713 sarcomeres) in jump muscles, and 0 ± 0 % (3 cells, 114 myofibrils, 982 sarcomeres) in IF muscles. Classifying the analyzed muscles by specialized biological functions (slow oxidative: leg muscle; and fast oxidative/glycolytic: jump, DF, and IF muscles) suggests that branching events are more frequent in slow-twitch muscles compared to fast-twitch muscles. Since this frequency pattern arises in both vertebrates and invertebrates, we posit that sarcomere branching is an evolutionarily conserved adaptation. Therefore, the long-standing belief that sarcomeres are only arranged in a linear fashion (i.e., end to end in series) must be revisited to improve our understanding of how muscle architecture impacts biological processes and musculoskeletal pathologies.

Massively parallel solution of the Lambert problem

This paper considers the possibility of massively parallel solution to the Lambert problem on graphics processing units. Several of the most popular solution algorithms were used for this problem. Software implementation of algorithms under consideration has been developed using Compute Unified Device Architecture technology that allows performing calculations on graphics processing units. A distinctive feature of this project is an attempt to use parallel programming within an iterative scheme. The developed algorithms have been tested on a number of typical tasks: contouring of Earth – Mars direct flight isolines and solution of the problem of a flight to a group of asteroids for the given start date and flight duration. For such tasks we give estimates of execution time and paralleling efficiency.

To what extent can the tiny parasitoid wasps, Eretmocerus mundus, fly upwind?

AbstractBody miniaturization in insects is predicted to result in decreased flight speed and therefore limited ability of these insects to fly upwind. Therefore, tiny insects are often regarded as relying on passive dispersal by winds. We tested this assumption in a wind tunnel by measuring the burst speed of Eretmocerus mundus (Mercet), a beneficial parasitoid wasp with body length <1 mm. Insects were filmed flying upwind towards a UV light source in a range of wind speed 0–0.5 m/s. The Insects flew towards the UV light in the absence and presence of wind but increased their flight speed in the presence of wind. They also changed flight direction to be directly upwind and maintained this body orientation even while drifted backwards relative to the ground by stronger winds. Field measurements showed that the average flight speed observed in the wind tunnel (0.3 m/s) is sufficient to allow flying between plants even when the wind speed above the vegetation was 3–5 folds higher. A simulation of the ability of the insects to control their flight trajectory towards a visual target (sticky traps) in winds show that the insects can manipulate their progress relative to the ground even when the wind speed exceeds their flight speed. The main factors determining the ability of the insects to reach the trap were trap diameter and the difference between insect flight speed and wind speed. The simulation also predicts the direction of arrival to the sticky target showing that many of the insects reach the target from the leeward side (i.e. by flight upwind). In light of these results, the notion that miniature insects passively disperse by winds is misleading because it disregards the ability of the insects to control their drift relative to the ground in winds that are faster than their flight speed.

Field testing an "acoustic lighthouse": Combined acoustic and visual cues provide a multimodal solution that reduces avian collision risk with tall human-made structures.

Billions of birds fatally collide with human-made structures each year. These mortalities have consequences for population viability and conservation of endangered species. This source of human-wildlife conflict also places constraints on various industries. Furthermore, with continued increases in urbanization, the incidence of collisions continues to increase. Efforts to reduce collisions have largely focused on making structures more visible to birds through visual stimuli but have shown limited success. We investigated the efficacy of a multimodal combination of acoustic signals with visual cues to reduce avian collisions with tall structures in open airspace. Previous work has demonstrated that a combination of acoustic and visual cues can decrease collision risk of birds in captive flight trials. Extending to field tests, we predicted that novel acoustic signals would combine with the visual cues of tall communication towers to reduce collision risk for birds. We broadcast two audible frequency ranges (4 to 6 and 6 to 8 kHz) in front of tall communication towers at locations in the Atlantic migratory flyway of Virginia during annual migration and observed birds' flight trajectories around the towers. We recorded an overall 12-16% lower rate of general bird activity surrounding towers during sound treatment conditions, compared with control (no broadcast sound) conditions. Furthermore, in 145 tracked "at-risk" flights, birds reduced flight velocity and deflected flight trajectories to a greater extent when exposed to the acoustic stimuli near the towers. In particular, the 4 to 6 kHz stimulus produced the greater effect sizes, with birds altering flight direction earlier in their trajectories and at larger distances from the towers, perhaps indicating that frequency range is more clearly audible to flying birds. This "acoustic lighthouse" concept reduces the risk of collision for birds in the field and could be applied to reduce collision risk associated with many human-made structures, such as wind turbines and tall buildings.

Analytic solution of in-plane vortex\u2013rotor interactions with arbitrary orientation and its impact on rotor trim

The general aerodynamic problem of arbitrarily oriented in-plane vortex-rotor interaction was investigated in the past only by numerical simulation. Just one special case of in-plane vortex-rotor interaction with the vortex axis in flight direction was recently solved analytically. In this article, the analytical solution for arbitrary in-plane vortex orientation and position relative to the rotor is given for the first time. The solution of the integrals involved as derived here encompasses and simplifies the previous derivation of the special case significantly. Results provide the vortex impact on rotor trim (thrust, aerodynamic rolling and pitching moments about the hub) and the rotor controls required to mitigate these disturbances. For the special case with the vortex axis in flight direction, the results are identical to the former solution and results for the other in-plane vortex orientations and positions agree with the numerical results obtained so far.

Interactive effects of body mass changes and species-specific morphology on flight behavior of chick-rearing Antarctic fulmarine petrels under diurnal wind patterns.

For procellariiform seabirds, wind and morphology are crucial determinants of flight costs and flight speeds. During chick‐rearing, parental seabirds commute frequently to provision their chicks, and their body mass typically changes between outbound and return legs. In Antarctica, the characteristic diurnal katabatic winds, which blow stronger in the mornings, form a natural experimental setup to investigate flight behaviors of commuting seabirds in response to wind conditions. We GPS‐tracked three closely related species of sympatrically breeding Antarctic fulmarine petrels, which differ in wing loading and aspect ratio, and investigated their flight behavior in response to wind and changes in body mass. Such information is critical for understanding how species may respond to climate change. All three species reached higher ground speeds (i.e., the speed over ground) under stronger tailwinds, especially on return legs from foraging. Ground speeds decreased under stronger headwinds. Antarctic petrels (Thalassoica antarctica; intermediate body mass, highest wing loading, and aspect ratio) responded stronger to changes in wind speed and direction than cape petrels (Daption capense; lowest body mass, wing loading, and aspect ratio) or southern fulmars (Fulmarus glacialoides; highest body mass, intermediate wing loading, and aspect ratio). Birds did not adjust their flight direction in relation to wind direction nor the maximum distance from their nests when encountering headwinds on outbound commutes. However, birds appeared to adjust the timing of commutes to benefit from strong katabatic winds as tailwinds on outbound legs and avoid strong katabatic winds as headwinds on return legs. Despite these adaptations to the predictable diurnal wind conditions, birds frequently encountered unfavorably strong headwinds, possibly as a result of weather systems disrupting the katabatics. How the predicted decrease in Antarctic near‐coastal wind speeds over the remainder of the century will affect flight costs and breeding success and ultimately population trajectories remains to be seen.

Human-Piloted Drone Racing: Visual Processing and Control

Humans race drones faster than algorithms, despite being limited to a fixed camera angle, body rate control, and response latencies in the order of hundreds of milliseconds. A better understanding of the ability of human pilots of selecting appropriate motor commands from highly dynamic visual information may provide key insights for solving current challenges in vision-based autonomous navigation. This paper investigates the relationship between human eye movements, control behavior, and flight performance in a drone racing task. We collected a multimodal dataset from 21 experienced drone pilots using a highly realistic drone racing simulator, also used to recruit professional pilots. Our results show task-specific improvements in drone racing performance over time. In particular, we found that eye gaze tracks future waypoints (i.e., gates), with first fixations occurring on average 1.5 seconds and 16 meters before reaching the gate. Moreover, human pilots consistently looked at the inside of the future flight path for lateral (i.e., left and right turns) and vertical maneuvers (i.e., ascending and descending). Finally, we found a strong correlation between pilots eye movements and the commanded direction of quadrotor flight, with an average visual-motor response latency of 220 ms. These results highlight the importance of coordinated eye movements in human-piloted drone racing. We make our dataset publicly available.

In Situ Measurements of Wind and Turbulence by a Motor Glider in the Andes

AbstractA Stemme S10-VT motor glider was equipped with a newly developed sensor suite consisting of a five-hole probe, an inertial navigation and global navigation satellite system, two temperature sensors, and a humidity sensor. By design, the system provides three-dimensional wind vector data that enable the analysis of atmospheric motion scales up to a temporal resolution of 10 Hz. We give a description of components and installation of the system, its calibration, and its performance. The accuracy for the measurement of the wind vector is estimated to be on the order of 0.5 m s−1. As part of the Southern Hemisphere Transport, Dynamics, and Chemistry (SouthTRAC) field campaign, 30 research flights were performed from September 2019 to January 2020. We present statistical analysis of the observations, discriminating pure motor flights from soaring flights in the lee waves of the Andes. We present histograms of flight altitude, airspeed, wind speed and direction, temperature, and relative humidity to document the atmospheric conditions. Probability density functions of vertical air velocity, turbulence kinetic energy (TKE), and dissipation rate complete the statistical analysis. Altogether, 41% of the flights are in weak, 14% in moderate, and 0.4% in strong mountain wave conditions according to thresholds for the measured vertical air velocity. As an exemplary case study, we compare measurements on 11 September 2019 to a high-resolution numerical weather prediction model. The case study provides a meaningful example of how data from soaring flights might be utilized for model validation on the mesoscale and within the troposphere.