Journal articles: 'High altitude flying'

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HIRAKI, Koju, Ryosuke TAKEI, and Reo MURAHASHI. "Kite-Flying in High Altitude." Proceedings of the International Conference on Motion and Vibration Control 2020.15 (2020): 10109. http://dx.doi.org/10.1299/jsmeintmovic.2020.15.10109.

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Yusoff, A. R., N. Darwin, Z. Majid, M. F. M. Ariff, and K. M. Idris. "COMPREHENSIVE ANALYSIS OF FLYING ALTITUDE FOR HIGH RESOLUTION SLOPE MAPPING USING UAV TECHNOLOGY." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W4 (March 6, 2018): 583–89. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w4-583-2018.

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<p><strong>Abstract.</strong> Unmanned Aerial Vehicle (UAV) is one of the geoinformation data acquisition technologies that popularly used for slope mapping. UAV is capable to produce high resolution imageries in a short period. In order to obtained suitable results in slope mapping, specific UAV mapping factors have to be followed and the selection of the optimum Ground Control Point (GCP) and the UAV flying altitude become the most important factors. This paper presents the production of high resolution slope map using UAV technology. The research involved with the following steps, (i) preparation of field work (i.e. determination of the number of GCPs and flying altitude) and the flight mission; (ii) processing and evaluating of UAV images, and (iii) production of slope map. The research was successfully conducted at Kulim, Kedah, Malaysia as the condition of slope in that area is prone to the landslide incidences. A micro rotary wing UAV system known as DJI Phantom 4 was used for collecting the high resolution images with various flying altitudes. Due to the un-accessibility of the slope area, all the GCPs are measured from the point cloud data that was acquired from the Pheonix AL-32 LiDAR system. The analysis shows that the coordinates (X, Y and Z) accuracy is influenced by the flying altitude. As the flying altitude increases, the coordinate’s accuracy also increased. Furthermore, the results also show that the coverage slope area and number of tie point increases when the flying altitude increases. This practical study contributed to the slope work activities where the specific requirements for flying altitudes have been clearly stated.</p>

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Melita, Carmelo Donato, Dario Calogero Guastella, Luciano Cantelli, Giuseppe Di Marco, Irene Minio, and Giovanni Muscato. "Low-Altitude Terrain-Following Flight Planning for Multirotors." Drones 4, no. 2 (June 25, 2020): 26. http://dx.doi.org/10.3390/drones4020026.

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Surveying with unmanned aerial vehicles flying close to the terrain is crucial for the collection of details that are not visible when flying at higher altitudes. This type of missions can be applied in several scenarios such as search and rescue, precision agriculture, and environmental monitoring, to name a few. We present a strategy for the generation of low-altitude trajectories for terrain following. The trajectory is generated taking into account the morphology of the area of interest, represented as a georeferenced Digital Surface Model (DSM), while ensuring a safe separation from any obstacle. The surface model of the scenario is created by using a UAV-based photogrammetry software, which processes the images acquired during a preliminary mission at high altitude. The solution was developed, tested, and verified both in simulation and in real scenarios with a multirotor equipped with low-cost sensing. The experimental results proved the validity of the generation of trajectories at altitudes lower than most of the works available in the literature. The images acquired during the low-altitude mission were processed to obtain a high-resolution reconstruction of the area as a representative application result.

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Alsahlani, Ahmad Abdulkarim, and Thurai Rahulan. "Aerofoil Design for Unmanned High-Altitude Aft-Swept Flying Wings." Journal of Aerospace Technology and Management 9, no. 3 (August 3, 2017): 335–45. http://dx.doi.org/10.5028/jatm.v9i3.838.

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Mingireanu, F. "HIGH ALTITUDE FLYING WING UAV FOR AUTOMATIC PAYLOAD RECOVERY AND HIGH ALTITUDE TESTS OF NOVEL PROPULSION UNITS." International Conference on Applied Mechanics and Mechanical Engineering 17, no. 17 (April 1, 2016): 1. http://dx.doi.org/10.21608/amme.2016.35173.

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Nazarali, Samir, Henry Liu, Maleeha Syed, Terry Wood, Samuel Asanad, Alfredo A. Sadun, and Rustum Karanjia. "Aircraft Cabin Pressurization and Concern for Non-Arteritic Anterior Ischemic Optic Neuropathy." Aerospace Medicine and Human Performance 91, no. 9 (September 1, 2020): 715–19. http://dx.doi.org/10.3357/amhp.5498.2020.

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BACKGROUND: Cabin pressurization is the process by which aircraft maintain a comfortable and safe environment for passengers flying at high altitudes. At high altitudes, most patients can tolerate changes in pressurization; however, passengers at high risk of hypoxia may experience ischemic events. The purpose of this study was to evaluate variations in pressurization of commercial aircraft at cruising altitude and describe its relevance in relation to patients with non-arteritic anterior ischemic optic neuropathy (NAION).METHODS: Altimeters were used to measure altitude and cabin altitude at cruising altitude aboard 113 commercial flights, including 53 narrow-body and 60 wide-body aircraft.RESULTS: Cabin altitude ranged from 4232 ft to 7956 ft at cruising altitudes ranging from 30,000 ft to 41,000 ft. The mean cabin altitude for all flights was 6309 876 ft. Narrow-body aircraft had a significantly higher mean cabin altitude (6739 829 ft) compared to wide-body aircraft (5929 733 ft). For all flights, the mean cruising altitude was 35,369 2881 ft with narrow-body aircraft cruising at a lower altitude of 34,238 2389 ft compared to wide-body aircraft at 36,369 2925 ft. Newer generation aircraft had a mean cabin altitude of 6066 837 ft, which was lower than the mean cabin altitude of older aircraft (6616 835 ft).DISCUSSION: Innovation in flight design has offered the ability for aircraft to fly at greater altitudes while maintaining lower cabin altitude. Those at high risk of hypoxia-induced complications may consider aircraft type when air travel is required.Nazarali S, Liu H, Syed M, Wood T, Asanad S, Sadun AA, Karanjia R. Aircraft cabin pressurization and concern for non-arteritic anterior ischemic optic neuropathy. Aerosp Med Hum Perform. 2020; 91(9):715719.

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Su, Li Chao, Zhen Xia Liu, and Ya Guo Lu. "Performance Research on the High-Altitude Valve of an Aero-Engine Ventilation System." Applied Mechanics and Materials 138-139 (November 2011): 540–47. http://dx.doi.org/10.4028/www.scientific.net/amm.138-139.540.

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For aero-engines, high-altitude valve is a key component, which is important to the high-altitude performance of ventilation system. However, theoretical researches or experimental tests of high-altitude valve are rare. To define whether the high-altitude valve can work normally during the whole flight envelope and to offer relational information for the improve design, this article focuses on the operation process and characteristic computation of high-altitude valve. Based on operational principle and structural analysis, using mechanics method, the high-altitude characteristic computation of high-altitude valve was done and the flight height where the valve closes was identified. In the same way, we analysed the static characteristic, getting the inner-cavity pressure in high-altitude flying state. Compared with the experimental results, the analytical methods and calculated values are validated to be accurate. The characteristic curves obtained can be directly used in the check and acceptance or further design of high-altitude valve.

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Xue, Fei, Gu Yunsong, Yuchao Wang, and Han Qin. "Research on control effectiveness of fluidic thrust vectoring." Science Progress 104, no. 1 (January 2021): 003685042199813. http://dx.doi.org/10.1177/0036850421998137.

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In view of the control effects of fluidic thrust vector technology for low-speed aircraft at high altitude/low density and low altitude/high density are studied. The S-A model of FLUENT software is used to simulate the flow field inside and outside the nozzle with variable control surface parameters, and the relationship between the area of control surface and the deflection effect of main flow at different altitudes is obtained. It is found that the fluidic thrust vectoring nozzle can effectively control the internal flow in the ground state and the high altitude/low density state. and the mainstream deflection angle can be continuously adjusted. The maximum deflection angle of the flow in the ground state is 21.86°, and the maximum deviation angle of the 20 km high altitude/low density state is 18.80°. The deflecting of the inner flow of the nozzle is beneficial to provide more lateral force and lateral torque for the aircraft. The high altitude/low density state is taken as an example. When the internal flow deflects 18.80°, the lateral force is 0.32 times the main thrust. For aircraft with high altitude and low density, sufficient lateral and lateral torque can make the flying aircraft more flexible, which can make up the shortcomings of the conventional rudder failure and even replace the conventional rudder surface.

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HORIGUCHI, Seiji, and Kinya OGAWA. "High altitude wind power generation system by means of a flying kite." Proceedings of the Symposium on Environmental Engineering 2004.14 (2004): 391–93. http://dx.doi.org/10.1299/jsmeenv.2004.14.391.

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Ceran, Elif Tugce, Tugce Erkilic, Elif Uysal-Biyikoglu, Tolga Girici, and Kemal Leblebicioglu. "Optimal energy allocation policies for a high altitude flying wireless access point." Transactions on Emerging Telecommunications Technologies 28, no. 4 (March 17, 2016): e3034. http://dx.doi.org/10.1002/ett.3034.

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Aralimarad, Prabhuraj, Andy M. Reynolds, Ka S. Lim, Don R. Reynolds, and Jason W. Chapman. "Flight altitude selection increases orientation performance in high-flying nocturnal insect migrants." Animal Behaviour 82, no. 6 (December 2011): 1221–25. http://dx.doi.org/10.1016/j.anbehav.2011.09.013.

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Caballero, F., L. Merino, J. Ferruz, and A. Ollero. "Vision-Based Odometry and SLAM for Medium and High Altitude Flying UAVs." Journal of Intelligent and Robotic Systems 54, no. 1-3 (July 27, 2008): 137–61. http://dx.doi.org/10.1007/s10846-008-9257-y.

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Mandlburger, G., R. Weiß, and T. Artz. "MAPPING OF WATER SURFACE LEVELS AND SLOPES WITH SINGLE PHOTON LIDAR – A CASE STUDY AT THE RIVER RHINE." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B1-2020 (August 6, 2020): 57–64. http://dx.doi.org/10.5194/isprs-archives-xliii-b1-2020-57-2020.

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Abstract. Precise knowledge of water surface level heights is crucial for safe ship navigation and as basis for calibration of hydrodynamic-numerical models. While Airborne Laser Scanning (ALS) is a well established technique for topographic mapping, ALS-based water surface mapping using conventional infrared lasers suffers from the high degree of specular reflection which leads to data voids for off-nadir angles beyond 5–7 degrees. The advent of single photon sensitive ALS systems using green laser sources presents the prospect of large-area, high-resolution water surface mapping due to the high receiver sensitivity and measurement rate of such systems. Building on previous studies on subject matters, we present the results of a pilot project initiated and conducted by the German Federal Institute of Hydrology (BfG, Koblenz) at the Rhine River. Three specific test sites with varying water surface and flow velocity properties were captured on October 30th and 31th, 2019 with the Leica SPL100 from flying altitudes of 3000 m, 2500 m, 1600 m, and 800 m, respectively. As anticipated, the water surface laser pulse density was high and exhibited 20–145 points/m2 depending on flying altitude. After quality control, strip adjustment, and point cloud analysis, three water surface classification methods were implemented based on: (i) height quantiles, (ii) point cloud segmentation, and (iii) inverse DTM filtering. All approaches featured relative and absolute water level height accuracies better than 10 cm. We conclude that Single Photon LiDAR based high resolution mapping of water surface levels and tilts is feasible when employing application specific data acquisition parameters, i.e., off-nadir angle &leq;10° and flying altitude &leq;3000 m.

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Gao, Zhen Xing, and Hong Bin Gu. "Safety Analysis of Aircraft Flying through Low Altitude Wind Shear." Applied Mechanics and Materials 97-98 (September 2011): 817–20. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.817.

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Low altitude microburst wind shear would do harm to aircrafts’ takeoff and landing. In order to analyze flight safety and advise better escape strategies, a mathematical model was built with high fidelity by a vortex ring based microburst model and a flight dynamics model with wind effects. A human pilot model which can describe characteristics of pilots such as skills, experiences, emotion, etc was embedded into the dynamics model. Since the key parameters of the microburst wind shear model and pilot model were set to be stochastic, the Monte Carlo method was adopted to obtain a numerical approximation of the probability density function of the minimum altitude and the F-factors for flight safety analysis.

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Zuppardi, G., G. Visone, R. Votta, and A. Schettino. "Analysis of Aerodynamic Performances of Experimental Flying Test Bed in High-Altitude Flight." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 225, no. 3 (August 11, 2010): 247–58. http://dx.doi.org/10.1243/09544100jaero873.

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Idkaidek, Nasir, and Ahmad Al-Ghazawi. "Effect of Flying at High Altitude on Early Exposure of Paracetamol in Humans." Drug Research 69, no. 06 (November 21, 2018): 348–51. http://dx.doi.org/10.1055/a-0790-4956.

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AbstractPharmacokinetics of paracetamol (APAP) was studied on-board during an air flight and compared to those on ground after 500 mg oral dose in 20 healthy human volunteer in parallel design study. Saliva samples were obtained every 15 min up to 2 h after dosing. Pharmacokinetic parameters were calculated by non compartmental analysis and one compartment models using Winnonlin program V5.2. Results have showed that on-board to ground ratios for area under curves AUC0→1, AUC0→2, time to reach maximum saliva concentration Tmax, absorption rate constant Ka and maximum saliva concentration Cmax were 0.62, 0.38, 1.01, 0.81 and 0.79 respectively. Effective membrane permeability coefficients were optimized by Nelder-Mead algorithm using Simcyp program V13. This showed similar rate of absorption and early exposure up to one hour, and lower bioavailability after 1 h on-board. This can be explained by the increased liver blood flow at high altitude that led to increased liver metabolism on-board. However, APAP elimination parameters were not calculated due to short sampling time. This suggests a need for dose adjustment on-board during long air flights, especially for narrow therapeutic index drugs with flow limited metabolism.

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Gao, Boya, Karl R. Wotton, Will L. S. Hawkes, Myles H. M. Menz, Don R. Reynolds, Bao-Ping Zhai, Gao Hu, and Jason W. Chapman. "Adaptive strategies of high-flying migratory hoverflies in response to wind currents." Proceedings of the Royal Society B: Biological Sciences 287, no. 1928 (June 3, 2020): 20200406. http://dx.doi.org/10.1098/rspb.2020.0406.

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Large migrating insects, flying at high altitude, often exhibit complex behaviour. They frequently elect to fly on winds with directions quite different from the prevailing direction, and they show a degree of common orientation, both of which facilitate transport in seasonally beneficial directions. Much less is known about the migration behaviour of smaller (10–70 mg) insects. To address this issue, we used radar to examine the high-altitude flight of hoverflies (Diptera: Syrphidae), a group of day-active, medium-sized insects commonly migrating over the UK. We found that autumn migrants, which must move south, did indeed show migration timings and orientation responses that would take them in this direction, despite the unfavourability of the prevailing winds. Evidently, these hoverfly migrants must have a compass (probably a time-compensated solar mechanism), and a means of sensing the wind direction (which may be determined with sufficient accuracy at ground level, before take-off). By contrast, hoverflies arriving in the UK in spring showed weaker orientation tendencies, and did not correct for wind drift away from their seasonally adaptive direction (northwards). However, the spring migrants necessarily come from the south (on warm southerly winds), so we surmise that complex orientation behaviour may not be so crucial for the spring movements.

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OOKUBO, Satoru, Toshiya SHIRAMATSU, Masayuki KURITA, Hidekazu KOHIRA, and Yoshinori TAKEUCHI. "Investigation of Mechanical Clearance Change with Thermal Flying-height Control Slider at High Altitude." Journal of Advanced Mechanical Design, Systems, and Manufacturing 4, no. 1 (2010): 32–41. http://dx.doi.org/10.1299/jamdsm.4.32.

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Bramberger, Martina, Andreas Dörnbrack, Henrike Wilms, Steffen Gemsa, Kevin Raynor, and Robert Sharman. "Vertically Propagating Mountain Waves—A Hazard for High-Flying Aircraft?" Journal of Applied Meteorology and Climatology 57, no. 9 (September 2018): 1957–75. http://dx.doi.org/10.1175/jamc-d-17-0340.1.

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AbstractStall warnings at flight level 410 (12.5 km) occurred unexpectedly during a research flight of the High Altitude and Long Range Research Aircraft (HALO) over Italy on 12 January 2016. The dangerous flight situation was mitigated by pilot intervention. At the incident location, the stratosphere was characterized by large horizontal variations in the along-track wind speed and temperature. On this particular day, strong northwesterly winds in the lower troposphere in concert with an aligned polar front jet favored the excitation and vertical propagation of large-amplitude mountain waves at and above the Apennines in Italy. These mountain waves carried large vertical energy fluxes of 8 W m−2 and propagated without significant dissipation from the troposphere into the stratosphere. While turbulence is a well-acknowledged hazard to aviation, this case study reveals that nonbreaking, vertically propagating mountain waves also pose a potential hazard, especially to high-flying aircraft. It is the wave-induced modulation of the ambient along-track wind speed that may decrease the aircraft speed toward the minimum needed stall speed.

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Liu, Juan, Yulin Zhang, Zhubin Wang, and Guozhen Zhao. "Validation of VR-based Immersive High-altitude Scene in Inducing Stress Response." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 63, no. 1 (November 2019): 2257–61. http://dx.doi.org/10.1177/1071181319631036.

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Cognitive impairment under stress is a topic of concern in the field of human factors. Compared to traditional stress-inducing paradigms, the current study aimed to establish a repeatable and easy-to-operate stress-inducing paradigm and verify its effectiveness in inducing an individual’s stress response. A VR-based immersive high-altitude scene and a corresponding simulated long prop was created and three stress-inducing tasks (“experiencing the high-altitude”, “rescuing the cat”, and “avoiding flying birds”) were designed. A cognitive task (n-back) was nested into the VR scene as well to assess the effects of stress on the cognitive performance. Participants were asked to accomplish the three stress-inducing tasks on the long board and the same n-back task before and after the stress. Both reported stress level and salivary cortisol level were collected. Results showed that the current VR-based immersive high-altitude scene was able to induce an individual’s stress response according to both subjective and objective indices, which could reach the similar level as that of the previous VR-based Trier Social Stress Test (TSST) paradigm.

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Reynolds, Andy M., Don R. Reynolds, Sanjay P. Sane, Gao Hu, and Jason W. Chapman. "Orientation in high-flying migrant insects in relation to flows: mechanisms and strategies." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1704 (September 26, 2016): 20150392. http://dx.doi.org/10.1098/rstb.2015.0392.

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High-flying insect migrants have been shown to display sophisticated flight orientations that can, for example, maximize distance travelled by exploiting tailwinds, and reduce drift from seasonally optimal directions. Here, we provide a comprehensive overview of the theoretical and empirical evidence for the mechanisms underlying the selection and maintenance of the observed flight headings, and the detection of wind direction and speed, for insects flying hundreds of metres above the ground. Different mechanisms may be used—visual perception of the apparent ground movement or mechanosensory cues maintained by intrinsic features of the wind—depending on circumstances (e.g. day or night migrations). In addition to putative turbulence-induced velocity, acceleration and temperature cues, we present a new mathematical analysis which shows that ‘jerks’ (the time-derivative of accelerations) can provide indicators of wind direction at altitude. The adaptive benefits of the different orientation strategies are briefly discussed, and we place these new findings for insects within a wider context by comparisons with the latest research on other flying and swimming organisms. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’.

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Nasir, Rizal E. M., and Wahyu Kuntjoro. "Longitudinal Flight Stability Augmentation of a Small Blended Wing-Body Aircraft with Canard as Control Surface." Applied Mechanics and Materials 393 (September 2013): 329–37. http://dx.doi.org/10.4028/www.scientific.net/amm.393.329.

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Transient response of an aircraft in longitudinal motion has two modes of oscillatory motion short period mode and phugoid modes and failure to achieve satisfactory level would mean poor flying and handling qualities leading to unnecessary pilot workload. This study proposes a stability augmentation system (SAS) in longitudinal flying modes for steady and level flight at all airspeeds and altitudes within Baseline-II E-2 BWBs operational flight envelope (OFE). The main controlling component of this stability augmentation system is a set of canard, a control surface located in front of the wing. It must be able to compensate Baseline-II E-2 BWB poor transient responses damping ratios so that good flying quality can be achieved. Observation from the transient responses of the unaugmented system signify high-frequency short-period oscillations with almost constant low damping ratio at an altitude, and low-frequency phugoid oscillation with varying damping ratio depending on airspeed. A conclusive behaviour of natural frequencies and damping ratios against dynamic pressure leads to the understanding on how dynamic pressure influences the flying qualities. Derivation of dynamic equations in terms of dynamic pressures enables one to design and device a feedback system to compensate poor flying qualities of the original unaugmented aircraft with conclusive relationship between important parameters and dynamic pressure are put in the overall dynamic equation. Two feedback gain systems, pitch attitude and pitch rate gains are scheduled based on dynamic pressure values and are combined into the aircraft longitudinal SAS. The proposed SAS has proven to be the suitable candidate for Baseline-II E-2 BWB as it is able to ensure Level 1 flying qualities, longitudinally.

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McCombs, Audrey, and Diane Debinski. "Summary of an Ongoing Population Study of Parnassius Clodius Butterflies." UW National Parks Service Research Station Annual Reports 38 (January 1, 2015): 71–74. http://dx.doi.org/10.13001/uwnpsrc.2015.4097.

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Climate change presents unique challenges to high-altitude, high-latitude flying insects such as butterflies, bees, and flies. Models predict that climate change will cause general range shifts toward the poles and high elevations (Parmesan and Yohe 2003, Root et al. 2003) and empirical studies confirm that these range shifts are occurring (Parmesan et al. 1999, Kerr et al. 2015). As the earth warms, animals already living at high elevations and/or high latitudes may have nowhere to go. Furthermore, the body temperature of insects is dependent on ambient temperatures, and therefore many aspects of their ecology and general biology (development, growth, survival, dispersal, mating) may be stressed by or incompatible with a changing climate. Finally, animal flight at altitude involves substantial aerodynamic and physiological challenges, and significant reductions in air density and oxygen constrain flight at higher elevations (Dillon and Dudley 2015). Moving up in elevation therefore may not be an option for some high-altitude fliers.

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Ji, Qi. "A Servo Control System of Dynamic Target Simulation Device for Aerial Camera." Applied Mechanics and Materials 220-223 (November 2012): 1345–49. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1345.

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This article introduces a dynamic target simulation device to evaluate dynamic image quality of the aerial camera. The device simulated the positional relationship of the sky and ground in the laboratory when aerial camera flies at high altitude. And it can be used to inspect camera image quality of aerial camera flying at high altitude in laboratory. At a same time, the article focuses on this servo control system of device, building a control model, and giving control strategy. The servo control system was proved stably and reliably after experimental verification. And it provides a strong guarantee for the test of the dynamic image.

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Guerra-Langan, Ana, Sergio Araujo-Estrada, and Shane Windsor. "Unmanned aerial vehicle control costs mirror bird behaviour when soaring close to buildings." International Journal of Micro Air Vehicles 12 (January 2020): 175682932094100. http://dx.doi.org/10.1177/1756829320941005.

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Small unmanned aerial vehicles (SUAVs) are suitable for many low-altitude operations in urban environments due to their manoeuvrability; however, their flight performance is limited by their on-board energy storage and their ability to cope with high levels of turbulence. Birds exploit the atmospheric boundary layer in urban environments, reducing their energetic flight costs by using orographic lift generated by buildings. This behaviour could be mimicked by fixed-wing SUAVs to overcome their energy limitations if flight control can be maintained in the increased turbulence present in these conditions. Here, the control effort required and energetic benefits for a SUAV flying parallel to buildings whilst using orographic lift was investigated. A flight dynamics and control model was developed for a powered SUAV and used to simulate flight control performance in different turbulent wind conditions. It was found that the control effort required decreased with increasing altitude and that the mean throttle required increased with greater radial distance to the buildings. However, the simulations showed that flying close to the buildings in strong wind speeds increased the risk of collision. Overall, the results suggested that a strategy of flying directly over the front corner of the buildings appears to minimise the control effort required for a given level of orographic lift, a strategy that mirrors the behaviour of gulls in high wind speeds.

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Govardhan, Gaurav, Sreedharan Krishnakumari Satheesh, Ravi Nanjundiah, Krishnaswamy Krishna Moorthy, and Surendran Suresh Babu. "Possible climatic implications of high-altitude black carbon emissions." Atmospheric Chemistry and Physics 17, no. 15 (August 10, 2017): 9623–44. http://dx.doi.org/10.5194/acp-17-9623-2017.

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Abstract. On account of its strong absorption of solar and terrestrial radiation, black carbon (BC) aerosol is known to impact large-scale systems, such as the Asian monsoon and the Himalayan glaciers, in addition to affecting the thermal structure of the lower atmosphere. While most studies focus on the near-surface abundance and impacts of BC, our study examines the implications of sharp and confined layers of high BC concentration (called elevated BC layers) at altitudes more than 4 km over the Indian region using the online regional chemistry transport model (WRF-Chem) simulations. These elevated BC layers were revealed in the recent in situ measurements using high-altitude balloons carried out on 17 March 2010, 8 January 2011 and 25 April 2011. Our study demonstrates that high-flying aircraft (with emissions from the regionally fine-tuned MACCity inventory) are the most likely cause of these elevated BC layers. Furthermore, we show that such aircraft-emitted BC can be transported to upper tropospheric or lower stratospheric heights ( ∼ 17 km) aided by the strong monsoonal convection occurring over the region, which is known to overshoot the tropical tropopause, leading to the injection of tropospheric air mass (along with its constituent aerosols) into the stratosphere. We show observational evidence for such an intrusion of tropospheric BC into the stratosphere over the Indian region using extinction coefficient and particle depolarisation ratio data from CALIOP Lidar on-board the CALIPSO satellite. We hypothesise that such intrusions of BC into the lower stratosphere and its consequent longer residence time in the stratosphere have significant implications for stratospheric ozone, especially considering the already reported ozone-depleting potential of BC.

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Scott, Graham R., and William K. Milsom. "Flying high: A theoretical analysis of the factors limiting exercise performance in birds at altitude." Respiratory Physiology & Neurobiology 154, no. 1-2 (November 2006): 284–301. http://dx.doi.org/10.1016/j.resp.2006.02.012.

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Hasan, Mohammad, Jelena Svorcan, Aleksandar Simonovic, Nikola Mirkov, and Olivera Kostic. "Optimal airfoil design and wing analysis for solar-powered high-altitude platform station." Thermal Science, no. 00 (2021): 241. http://dx.doi.org/10.2298/tsci210419241s.

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The ability of flying continuously over prolonged periods of time has become target of numerous research studies performed in recent years in both the fields of civil aviation and unmanned drones. High-altitude platform stations are aircrafts that can operate for an extended period of time at altitudes 17 km above sea level and higher. The aim of this paper is to design and optimize a wing for such platforms and computationally investigate its aerodynamic performance. For that purpose, two-objective genetic algorithm, class shape transformation and panel method were combined and used to define different airfoils with the highest lift-to-drag ratio and maximal lift coefficient. Once the most suitable airfoil was chosen, polyhedral half-wing was modeled and its aerodynamic performances were estimated using the computational fluid dynamics approach. Flow simulations of transitional flow at various angles-of-attack were realized in ANSYS FLUENT and various quantitative and qualitative results are presented, such as aerodynamic coefficient curves and flow visualizations. In the end, daily mission of the aircraft is simulated and its energy requirement is estimated. In order to be able to cruise above Serbia in July, an aircraft weighing 150 kg must accumulate 17 kWh of solar energy per day.

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Ånell, Rickard, Mikael Grönkvist, Mikael Gennser, and Ola Eiken. "Evolution and Preservation of Venous Gas Emboli at Alternating High and Moderate Altitude Exposures." Aerospace Medicine and Human Performance 91, no. 1 (January 1, 2020): 11–17. http://dx.doi.org/10.3357/amhp.5447.2020.

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INTRODUCTION: The evolution and preservation of venous gas emboli (VGE), as markers of decompression stress, were investigated during alternating high- and moderate altitude exposures, thus, simulating a fighter aircraft high-altitude flight, interrupted by refueling excursions to lower altitudes.METHODS: Eight men served as subjects during three normoxic simulated altitude exposures: High = 90 min at 24,000 ft; High-Low = three × 30 min at 24,000 ft, interspersed by two 30-min intervals at 15,000 ft; Low = 90 min at 15,000 ft. VGE scores were assessed by cardiac ultrasound, using a 5-grade scale. Respiratory nitrogen exchange was measured continuously using a modified closed-circuit electronic rebreather.RESULTS: Both High and High-Low induced persistent VGE, with no inter-condition difference either at rest [median (range): High: 1 (0-3), High-Low: 2 (0-3)] or during unloaded knee-bends [High: 3 (1-4), High-Low: 3 (0-4)], whereas VGE was considerably less in Low, both at rest [0 (0-1)] and during knee-bends [0 (0-2)]. In High-Low, VGE decreased temporarily during the 15,000-ft excursions, but resumed pre-excursion values upon return to 24,000 ft. During the final descent to ground level, VGE were more persistent following High-Low than High. In both High and Low, nitrogen was continuously washed out at altitude, whereas in High-Low, the washout at 24,000 ft was interrupted by nitrogen uptake at 15,000 ft.DISCUSSION: In normoxic conditions, long-duration flying at a cabin altitude of 24,000 ft is associated with substantial VGE occurrence, which is not abolished by intermittent excursions to a cabin altitude of 15,000 ft.Ånell R, Grönkvist M, Gennser M, Eiken O. Evolution and preservation of venous gas emboli at alternating high and moderate altitude exposures. Aerosp Med Hum Perform. 2020; 91(1):11–17.

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Maruca, Bennett A., Raffaele Marino, David Sundkvist, Niharika H. Godbole, Stephane Constantin, Vincenzo Carbone, and Herb Zimmerman. "Overview of and first observations from the TILDAE High-Altitude Balloon Mission." Atmospheric Measurement Techniques 10, no. 4 (April 26, 2017): 1595–607. http://dx.doi.org/10.5194/amt-10-1595-2017.

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Abstract. Though the presence of intermittent turbulence in the stratosphere has been well established, much remains unknown about it. In situ observations of this phenomenon, which have provided the greatest details of it, have mostly been achieved via sounding balloons (i.e., small balloons which burst at peak altitude) carrying constant-temperature hot-wire anemometers (CTAs). The Turbulence and Intermittency Long-Duration Atmospheric Experiment (TILDAE) was developed to test a new paradigm for stratospheric observations. Rather than flying on a sounding balloon, TILDAE was incorporated as an add-on experiment to the payload of a NASA long-duration balloon mission that launched in January 2016 from McMurdo Station, Antarctica. Furthermore, TILDAE's key instrument was a sonic anemometer, which (relative to a CTA) provides better-calibrated measurements of wind velocity and a more robust separation of velocity components. During the balloon's ascent, TILDAE's sonic anemometer provided atmospheric measurements up to an altitude of about 18 km, beyond which the ambient air pressure was too low for the instrument to function properly. Efforts are currently underway to scientifically analyze these observations of small-scale fluctuations in the troposphere, tropopause, and stratosphere and to develop strategies for increasing the maximum operating altitude of the sonic anemometer.

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Kang, Jungpyo, Kwanjung Yee, and Gyujin Shim. "Operational Feasibility Study of High Altitude Balloon Platform based on the Wind Environment in South Korea." Defence Science Journal 70, no. 2 (March 9, 2020): 153–58. http://dx.doi.org/10.14429/dsj.70.14705.

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Naval helicopters flying at extremely low altitudes often face communication problems when the helicopter is located in the distance from the mother ship. Accordingly, new attention is being cast on the high altitude balloon (HAB) to solve this problem due to its cost-effectiveness and ability of rapid deployment to the battlefield. The balloon is one of a lighter-than-air vehicle that the blowing wind determines its speed, direction, and travel distance. Therefore, it is likely that seasonal changes in wind conditions will restrict the operation of the balloon. In this paper, the feasibility study of the balloon, which is regarded as a future communication relay platform, on the theater of operation of the Republic of Korea Navy the First Fleet was performed. The trends of the balloon trajectory for five years (2014 ~ 2018) with respect to seasonal wind variations were investigated employing the numerical trajectory prediction program. Simulated balloon trajectories of summer and winter showed considerable differences due to seasonal wind. Summer season was found that it has the most favorite flight environment for the balloon campaign. Upon reflecting on the simulation results, the HAB operating procedure, which capitalised on the Ulleungdo, was also suggested.

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Misirovs, Rasads, and Shwan Mohamad. "Reverse Squeeze Maxillary Sinus Barotrauma." Ear, Nose & Throat Journal 99, no. 1 (February 15, 2019): NP9—NP10. http://dx.doi.org/10.1177/0145561319825556.

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A young female patient presented to ear, nose, and throat clinic with long history of left sided facial pain exacerbated while flying and being in high altitude. Examination of nasal cavity and computed tomography scan of sinuses suggested left maxillary sinus barotrauma. Endoscopic sinus surgery was performed completely resolving her symptoms. Based on her symptoms and examination findings she had reverse squeeze sinus barotrauma.

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Sedlock, Jodi L., Alexander M. Stuart, Finbarr G. Horgan, Buyung Hadi, Angela Como Jacobson, Phillip A. Alviola, and James D. V. Alvarez. "Local-Scale Bat Guild Activity Differs with Rice Growth Stage at Ground Level in the Philippines." Diversity 11, no. 9 (August 27, 2019): 148. http://dx.doi.org/10.3390/d11090148.

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High-flying insectivorous bats, as wide-ranging generalist insectivores, are valuable consumers of high-altitude migrating pests of rice in Southeast Asia. Here, we documented the behavior of relatively low-flying bats over irrigated rice to elucidate their potential role as predators of rice-associated pest insects in the Philippines. Specifically, we tested the local-scale effects of rice stage, particularly seedling and late vegetative stages, and time of night on acoustic activity of bats foraging near ground level within three functional guilds (based on foraging distance from background clutter). We also monitored bat activity from two 50 m-high towers to assess the vertical extent of relatively low-flying guilds, as well as document high-flying bat guild presence and temporal behavior. At ground level, the most active guild biased their activity and feeding over early growth stage fields, but also foraged at tower level. Activity of the bat guild adept at foraging closest to vegetation did not vary with time of night or rice stage and was absent from tower recordings. High-flying bats were predictably rare at rice level, but exhibited high foraging intensity at 50 m. Given the well-documented, sequential arrival of insect guilds with growth stage, these data suggest that at ground level edge-space bats may be important consumers of detritivores (e.g., mosquitoes). Moreover, our data suggest that just as habitat heterogeneity enhances the services of arthropod predators, these management practices also enhance bat activity and, presumably, their contribution to pest suppression.

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DiMaggio, Alexandria M., Humberto L. Perotto-Baldivieso, J. Alfonso Ortega-S., Chase Walther, Karelys N. Labrador-Rodriguez, Michael T. Page, Jose de la Luz Martinez, Sandra Rideout-Hanzak, Brent C. Hedquist, and David B. Wester. "A Pilot Study to Estimate Forage Mass from Unmanned Aerial Vehicles in a Semi-Arid Rangeland." Remote Sensing 12, no. 15 (July 29, 2020): 2431. http://dx.doi.org/10.3390/rs12152431.

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The application of unmanned aerial vehicles (UAVs) in the monitoring and management of rangelands has exponentially increased in recent years due to the miniaturization of sensors, ability to capture imagery with high spatial resolution, lower altitude platforms, and the ease of flying UAVs in remote environments. The aim of this research was to develop a method to estimate forage mass in rangelands using high-resolution imagery derived from the UAV using a South Texas pasture as a pilot site. The specific objectives of this research were to (1) evaluate the feasibility of quantifying forage mass in semi-arid rangelands using a double sampling technique with high-resolution imagery and (2) to compare the effect of altitude on forage mass estimation. Orthoimagery and digital surface models (DSM) with a resolution <1.5 cm were acquired with an UAV at altitudes of 30, 40, and 50 m above ground level (AGL) in Duval County, Texas. Field forage mass data were regressed on volumes obtained from a DSM. Our results show that volumes estimated with UAV data and forage mass as measured in the field have a significant relationship at all flight altitudes with best results at 30-m AGL (r2 = 0.65) and 50-m AGL (r2 = 0.63). Furthermore, the use of UAVs would allow one to collect a large number of samples using a non-destructive method to estimate available forage for grazing animals.

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Bickler, P. E., S. O. Koh, and J. W. Severinghaus. "Effects of hypoxia and hypocapnia on brain redox balance in ducks." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 257, no. 1 (July 1, 1989): R132—R135. http://dx.doi.org/10.1152/ajpregu.1989.257.1.r132.

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Low arterial CO2 tension (PaCO2) experienced by birds during high-altitude flight may result in cerebral vasoconstriction with reduced cerebral O2 delivery. To test this, brain redox balance and blood volume were studied during severe hypocapnia (PaCO2 11-20 mmHg) in ducks. Cerebrocortical redox balance, measured as relative [NADH], and blood volume were measured simultaneously with a fiber-optic fluorometer-reflectometer. Cerebrocortical blood volume (an index of blood flow) fell nearly linearly with PaCO2 during severe hypocapnia, even during severe hypoxemia. Cerebrocortical redox balance was shifted toward reduction of NADH ([NADH] increased) by both hypoxemia and hypocapnia. If hypocapnia causes similar changes in brain blood flow during high-altitude flight, tissue hypoxia will be exacerbated. Tolerance of brain tissue hypoxia during flight may be an important adaptation in high-flying birds.

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TODOROKI, Chiaki, Tomoyuki KONDO, and Yasutake TAKAHASHI. "OS0203 High Altitude Wind Power Monitoring System using Kite based Tethered Flying Robot with Lifting Mount." Proceedings of Conference of Kanto Branch 2016.22 (2016): _OS0203–1_—_OS0203–2_. http://dx.doi.org/10.1299/jsmekanto.2016.22._os0203-1_.

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Jones, A. E., P. S. Anderson, E. W. Wolff, H. K. Roscoe, G. J. Marshall, A. Richter, N. Brough, and S. R. Colwell. "Vertical structure of Antarctic tropospheric ozone depletion events: characteristics and broader implications." Atmospheric Chemistry and Physics Discussions 10, no. 3 (March 29, 2010): 8189–246. http://dx.doi.org/10.5194/acpd-10-8189-2010.

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Abstract. The majority of tropospheric ozone depletion event (ODE) studies have focussed on time-series measurements, with comparatively few studies of the vertical component. Those that exist have almost exclusively used free-flying balloon-borne ozonesondes and almost all have been conducted in the Arctic. Here we use measurements from two separate Antarctic field experiments to examine the vertical profile of ozone during Antarctic ODEs. We use tethersonde data to probe details in the lowest few hundred meters and find considerable structure in the profiles associated with complex atmospheric layering. The profiles were all measured at wind speeds less than 7 ms−1, and on each occasion the lowest inversion height lay between 10 m and 40 m. We also use data from a free-flying ozonesonde study to select events where ozone depletion was recorded at altitudes >1 km above ground level. Using ERA-40 meteorological charts, we find that on every occasion the high altitude depletion was preceded by an atmospheric low pressure system. An examination of limited published ozonesonde data from other Antarctic stations shows this to be a consistent feature. Given the link between BrO and ODEs, we also examine ground-based and satellite BrO measurements, and find a strong association between enhanced BrO and atmospheric low pressure systems. The results suggest that, in Antarctica, such depressions are responsible for driving high altitude ODEs and for generating the large-scale BrO clouds observed from satellites. In the Arctic, the prevailing meteorology differs from that in Antarctica, but we show that major low pressure systems in the Arctic, when they occur, can also generate BrO clouds. Such depressions thus appear to be fundamental when considering the broader influence of ODEs, particularly in Antarctica, such as halogen export and the radiative influence of ozone-depleted air masses.

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Jones, A. E., P. S. Anderson, E. W. Wolff, H. K. Roscoe, G. J. Marshall, A. Richter, N. Brough, and S. R. Colwell. "Vertical structure of Antarctic tropospheric ozone depletion events: characteristics and broader implications." Atmospheric Chemistry and Physics 10, no. 16 (August 24, 2010): 7775–94. http://dx.doi.org/10.5194/acp-10-7775-2010.

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Abstract. The majority of tropospheric ozone depletion event (ODE) studies have focussed on time-series measurements, with comparatively few studies of the vertical component. Those that exist have almost exclusively used free-flying balloon-borne ozonesondes and almost all have been conducted in the Arctic. Here we use measurements from two separate Antarctic field experiments to examine the vertical profile of ozone during Antarctic ODEs. We use tethersonde data to probe details in the lowest few hundred meters and find considerable structure in the profiles associated with complex atmospheric layering. The profiles were all measured at wind speeds less than 7 ms−1, and on each occasion the lowest inversion height lay between 10 m and 40 m. We also use data from a free-flying ozonesonde study to select events where ozone depletion was recorded at altitudes >1 km above ground level. Using ERA-40 meteorological charts, we find that on every occasion the high altitude depletion was preceded by an atmospheric low pressure system. An examination of limited published ozonesonde data from other Antarctic stations shows this to be a consistent feature. Given the link between BrO and ODEs, we also examine ground-based and satellite BrO measurements and find a strong association between atmospheric low pressure systems and enhanced BrO that must arise in the troposphere. The results suggest that, in Antarctica, such depressions are responsible for driving high altitude ODEs and for generating the large-scale BrO clouds observed from satellites. In the Arctic, the prevailing meteorology differs from that in Antarctica, but, while a less common effect, major low pressure systems in the Arctic can also generate BrO clouds. Such depressions thus appear to be fundamental when considering the broader influence of ODEs, certainly in Antarctica, such as halogen export and the radiative influence of ozone-depleted air masses.

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Galiński, Cezary, Magdalena Gronowska, Wieńczysław Stalewski, and Konrad Gumowski. "Design And Investigation Of Flat–Upper–Surface Airfoil." MATEC Web of Conferences 304 (2019): 02004. http://dx.doi.org/10.1051/matecconf/201930402004.

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Attempts to build solar High Altitude Long Endurance (HALE) airplanes are more and more frequent. In the future such airplanes may appear very useful for the economy because they may replace geostationary satellites in several applications for a fraction of cost. Unfortunately, necessary data on altitude effect on photovoltaic cells and batteries performance are not easily available. Therefore, flying testbed for their inexpensive testing is needed. Flat–upper surface airfoil was designed for application in small UAV dedicated for photovoltaic cells investigation at various altitudes. It should enable installation of rigid cells on the top of the wing without significant reduction of aerodynamic performance. It should also decrease a risk of damage of flexible cells due to the significant bending of long aspect ratio, elastic wings. This paper contains description of the design methodology, design assumptions and obtained results. Moreover experiment undertaken to evaluate the design is described as well. The wind tunnel and a semi–span model used for this experiment are presented together with obtained results. The model has exactly the same structure as envisaged structure of UAV, so flexibility of the wing is taken into account.

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Wang, Hao, Jian Liu, and Honghu Ji. "Ground experimental simulation method of infrared radiation of high altitude aircraft’s surface." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 8 (July 26, 2018): 2980–91. http://dx.doi.org/10.1177/0954410018790138.

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It is difficult and costly to accurately measure the spectral and spatial distributions of the infrared radiation signature of a high altitude aircraft’s surface at relatively low temperatures. To reduce the experimental cost, simulated experimental measurement on the ground is usually made to measure its infrared signature. However, there are three main difficulties in the ground measurement: (1) it is difficult to simulate the temperature at high altitude which is much lower than the temperature near the ground; (2) it is difficult to accurately measure the infrared signature of a low temperature surface on the ground; and (3) it is difficult to measure the infrared signature of a prototype aircraft surface. To solve these problems, a ground experimental simulation method to obtain the infrared signature of a high altitude aircraft’s surface is developed, which makes it possible to use a scale model (scale factor M) at relatively higher temperature ( n times the temperature of the aircraft’s surface) to experimentally simulate the infrared signature of the actual aircraft’s surface. The results show that the integrated radiation intensity in the wavelength band between λ1 and λ2 of an original flying aircraft’s surface at a temperature range from T1 to T2 is equal to [Formula: see text] times the integrated radiation intensity in the wavelength band between λ1/ n and λ2/ n of the scale test surface model on the ground at a temperature range from nT1 to nT2.

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Francis, Raymond, Ronald Vincent, Jean-Marc Noël, Pascal Tremblay, Daniel Desjardins, Alex Cushley, and Matthew Wallace. "The Flying Laboratory for the Observation of ADS-B Signals." International Journal of Navigation and Observation 2011 (November 10, 2011): 1–5. http://dx.doi.org/10.1155/2011/973656.

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Automatic dependent surveillance-broadcast (ADS-B) is a system in which aircraft continually transmit their identity and GPS-derived navigational information. ADS-B networks for air traffic monitoring have already been implemented in areas around the world, but ground stations cannot be installed in midocean and are difficult to maintain in the Arctic, leaving a coverage gap for oceanic and high latitude airspace. A potential solution for worldwide tracking of aircraft is through the monitoring of aircraft-transmitted ADS-B signals using satellite-borne receivers. To investigate this possibility, a high altitude balloon experiment was carried out in June 2009 to determine if ADS-B signals can be detected from near space. The Flying Laboratory for the Observation of ADS-B Transmissions (FLOAT) was the first stratospheric platform to collect ADS-B data. The FLOAT mission successfully demonstrated the reception of ADS-B signals from near space, paving the way to the development of a space-based ADS-B system.

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Kibzun, A. I., M. N. Krasil’shchikov, V. L. Miroshkin, and K. I. Sypalo. "Trajectory control of a high altitude hypervelocity flying vehicle in the midcourse active phase of the flight." Journal of Computer and Systems Sciences International 52, no. 4 (July 2013): 628–36. http://dx.doi.org/10.1134/s1064230713040102.

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Smith, W. L., D. K. Zhou, A. M. Larar, S. A. Mango, H. B. Howell, R. O. Knuteson, H. E. Revercomb, and W. L. Smith. "The NPOESS Airborne Sounding Testbed Interferometer—Remotely Sensed Surface and Atmospheric Conditions during CLAMS." Journal of the Atmospheric Sciences 62, no. 4 (April 1, 2005): 1118–34. http://dx.doi.org/10.1175/jas3384.1.

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Abstract During the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS), the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed-Interferometer (NAST-I), flying aboard the high-altitude Proteus aircraft, observed the spatial distribution of infrared radiance across the 650–2700 cm−1 (3.7–15.4 μm) spectral region with a spectral resolution of 0.25 cm−1. NAST-I scans cross track with a moderate spatial resolution (a linear ground resolution equal to 13% of the aircraft altitude at nadir). The broad spectral coverage and high spectral resolution of this instrument provides abundant information about the surface and three-dimensional state of the atmosphere. In this paper, the NAST-I measurements and geophysical product retrieval methodology employed for CLAMS are described. Example results of surface properties and atmospheric temperature, water vapor, ozone, and carbon monoxide distributions are provided. The CLAMS NAST-I geophysical dataset is available for use by the scientific community.

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Belmonte, Lidia M., Arturo S. García, Rafael Morales, Jose Luis de la Vara, Francisco López de la Rosa, and Antonio Fernández-Caballero. "Feeling of Safety and Comfort towards a Socially Assistive Unmanned Aerial Vehicle That Monitors People in a Virtual Home." Sensors 21, no. 3 (January 29, 2021): 908. http://dx.doi.org/10.3390/s21030908.

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Unmanned aerial vehicles (UAVs) represent a new model of social robots for home care of dependent persons. In this regard, this article introduces a study on people’s feeling of safety and comfort while watching the monitoring trajectory of a quadrotor dedicated to determining their condition. Three main parameters are evaluated: the relative monitoring altitude, the monitoring velocity and the shape of the monitoring path around the person (ellipsoidal or circular). For this purpose, a new trajectory generator based on a state machine, which is successfully implemented and simulated in MATLAB/Simulink®, is described. The study is carried out with 37 participants using a virtual reality (VR) platform based on two modules, UAV simulator and VR Visualiser, both communicating through the MQTT protocol. The participants’ preferences have been a high relative monitoring altitude, a high monitoring velocity and a circular path. These choices are a starting point for the design of trustworthy socially assistive UAVs flying in real homes.

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Lillie, C. F. "Ultraviolet Observations of the Zodiacal Light and the Origin of Interplanetary Dust Grains." International Astronomical Union Colloquium 126 (1991): 151–54. http://dx.doi.org/10.1017/s0252921100066677.

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AbstractSurface brightness photometry of the night sky from rocket and satellite experiments shows an increase in the scattering efficiency of interplanetary dust grains in the 1500 to 3000 \ region of the spectrum. This increase is best explained by the presence of small dielectric particles with a mean radius of 0.04 microns. The most likely source of these grains is the dissolution of agglomerates of these particles which are released by comets during their perihelion passage. Many of these agglomerates have been collected in the Earth’s atmosphere by high flying aircraft. Submicron particles swept up from interplanetary space may be responsible for the high altitude haze observed in planetary atmospheres.

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Nakata, Toshiyuki, Nathan Phillips, Patrício Simões, Ian J. Russell, Jorn A. Cheney, Simon M. Walker, and Richard J. Bomphrey. "Aerodynamic imaging by mosquitoes inspires a surface detector for autonomous flying vehicles." Science 368, no. 6491 (May 7, 2020): 634–37. http://dx.doi.org/10.1126/science.aaz9634.

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Some flying animals use active sensing to perceive and avoid obstacles. Nocturnal mosquitoes exhibit a behavioral response to divert away from surfaces when vision is unavailable, indicating a short-range, mechanosensory collision-avoidance mechanism. We suggest that this behavior is mediated by perceiving modulations of their self-induced airflow patterns as they enter a ground or wall effect. We used computational fluid dynamics simulations of low-altitude and near-wall flights based on in vivo high-speed kinematic measurements to quantify changes in the self-generated pressure and velocity cues at the sensitive mechanosensory antennae. We validated the principle that encoding aerodynamic information can enable collision avoidance by developing a quadcopter with a sensory system inspired by the mosquito. Such low-power sensing systems have major potential for future use in safer rotorcraft control systems.

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Langille, Jeffery, Daniel Letros, Adam Bourassa, Brian Solheim, Doug Degenstein, Fabien Dupont, Daniel Zawada, and Nick D. Lloyd. "Spatial heterodyne observations of water (SHOW) from a high-altitude airplane: characterization, performance, and first results." Atmospheric Measurement Techniques 12, no. 1 (January 25, 2019): 431–55. http://dx.doi.org/10.5194/amt-12-431-2019.

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Abstract. The Spatial Heterodyne Observations of Water instrument (SHOW) is a limb-sounding satellite prototype that utilizes the Spatial Heterodyne Spectroscopy (SHS) technique, operating in a limb-viewing configuration, to observe limb-scattered sunlight in a vibrational band of water vapour within a spectral window from 1363 to 1366 nm. The goal is to retrieve high vertical and horizontal resolution measurements of water vapour in the upper troposphere and lower stratosphere. The prototype instrument has been configured for observations from NASA's ER-2 high-altitude airborne remote science airplane. Flying at a maximum altitude of ∼21.34 km with a maximum speed of ∼760 km h−1, the ER-2 provides a stable platform to simulate observations from a low-earth orbit satellite. Demonstration flights were performed from the ER-2 during an observation campaign from 15 to 22 July 2017. In this paper, we present the laboratory characterization work and the level 0 to level 1 processing of flight data that were obtained during an engineering flight performed on 18 July 2017. Water vapour profile retrievals are presented and compared to in situ radiosonde measurements made of the same approximate column of air. These measurements are used to validate the SHOW measurement concept and examine the sensitivity of the technique.

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Albertson, R., S. Schoenung, M. Fladeland, F. Cutler, and B. Tagg. "ENABLING EARTH SCIENCE MEASUREMENTS WITH NASA UAS CAPABILITIES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-7/W3 (April 30, 2015): 1111–17. http://dx.doi.org/10.5194/isprsarchives-xl-7-w3-1111-2015.

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NASA’s Airborne Science Program (ASP) maintains a fleet of manned and unmanned aircraft for Earth Science measurements and observations. The unmanned aircraft systems (UAS) range in size from very large (Global Hawks) to medium (SIERRA, Viking) and relatively small (DragonEye). UAS fly from very low (boundary layer) to very high altitude (stratosphere). NASA also supports science and applied science projects using UAS operated by outside companies or agencies. The aircraft and accompanying data and support systems have been used in numerous investigations. For example, Global Hawks have been used to study both hurricanes and atmospheric composition. SIERRA has been used to study ice, earthquake faults, and coral reefs. DragonEye is being used to measure volcanic emissions. As a foundation for NASA’s UAS work, Altair and Ikhana not only flew wildfires in the US, but also provided major programs for the development of real-time data download and processing capabilities. In 2014, an advanced L-band Synthetic Aperture Radar flew for the first time on Global Hawk, demonstrating UAVSAR, which has been flying successfully on a manned aircraft. This paper focuses on two topics: 1) results of a NASA program called UAS-Enabled Earth Science, in which three science teams flew UAS to demonstrate platform and sensor performance, airspace integration, and applied science results from the data collected; 2) recent accomplishments with the high altitude, long-duration Global Hawks. The challenges experienced with flying UAS are discussed. Recent upgrades to data processing, communications, tracking and flight planning systems are described.

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Ahsan, Mohammad Ahmed, Umar Rashed Munir, Mushtaq Ahmad, and Md Shahidullah. "Effects of Smoking on Pilots of Bangladesh Air Force in Dhaka Area." Journal of Armed Forces Medical College, Bangladesh 12, no. 1 (January 24, 2016): 22–27. http://dx.doi.org/10.3329/jafmc.v12i1.39962.

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Introduction: Smokers have a high morbidity and mortality rate and the causes of excess morbidity and mortality include lung cancer, COPD (Chronic Obstructive Pulmonary Disease) and cor pulmonale. An estimated 100 million people died in the 20th century from tobacco-associated diseases. Smoking also affects the performance and cause physical deterioration of pilots. Objectives: To evaluate the effects of smoking on pilots of Bangladesh Air Force (BAF), Dhaka area. Materials and Methods: This cross sectional study was conducted during the period of January to June 2014 among the available pilots of different age and ranks of 6 flying squadrons of BAF Dhaka area. Data were collected by using a pre-tested semistructured questionnaire distributed among the pilots. Information were also collected from Central Medical Board (CMB), BAF about total number of pilots placed in low medical category and nature of their sickness. Finally chest X-ray and ECG of the pilots were done to find out any respiratory and cardiovascular abnormalities. Data obtained were entered into SPSS version 21.0 for analysis. Results: Total 190 pilots were interviewed and among them, 80(42%) were smokers and 110(58%) were non-smokers. Most of the pilots were within the age group of 26-30 years (30%). Out of 80 smoker, 37(46%) smoked for more than 10 years, rest smoked for 10 years and less. Stress was the most common cause of starting smoking (96.3%). Fifty eight (72.5%) pilots agreed that their stamina and physical efficiency decreased due to smoking, 21 (26.3%) experienced breathlessness at high altitude, 26(32.5%) experienced visual disturbance during night flying. Fifty three (66.3%) pilots complained of occasional episode of palpitation along with increase in pulse rate. Thirty one (39%) experienced occasional headache during high altitude flight, 58(72.5%) had heart burn related to smoking. Thirty eight (47.5%) had occasional bouts of cough with sputum and 40(50%) complained of occasional gum bleeding. These pilots also informed that they reported sick several times for headache, heart burn, cough and URTI (Upper Respiratory Tract Infection) and were unfit for flying duties. During January-June 2014, a total of 10 pilots of BAF Dhaka area were placed in low medical category out of them 6 (60%) pilots had smoking habits and suffered from IHD-4 (Ischemic Heart Disease) and HTN-2 (Hypertension). There was statistically significant association between number of the cigarette smoked, period of smoking and physical deterioration of smoker pilots (P<0.05). Those who smoked more than 10 sticks/day and more than 10 years had moderate to severe physical deterioration. Conclusion: Smoking adversely affects all systems of human body. It impairs altitude tolerance, early induction of hypoxia, impairment of night vision. It affects autonomic systems and thus impairs all compensatory mechanism needed at higher altitudes. Morbidity and mortality related to smoking have linear relation. Pilots must be indoctrinated not to smoke for the sake of their safety flight, own life, their families and the nation. Journal of Armed Forces Medical College Bangladesh Vol.12(1) 2016: 22-27

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ABD MUKTI, SHAHRUL NIZAN, and Khairul Nizam Tahar. "LOW ALTITUDE PHOTOGRAMMETRY FOR URBAN ROAD MAPPING." Built Environment Journal 18, no. 1 (February 8, 2021): 31. http://dx.doi.org/10.24191/bej.v18i1.10205.

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Road connection has high impact on the city development. It helps boost the economic environment along the road. Therefore, it is important to maintain and divide by their traffic flow and road reserve well to determine the privilege of maintenance and budget contribution for every year. Road opens up the relation of intercity and urban as it gives the impact of development along the road. To manage road over the country, geometry data of road is needed for decision making and project well management. The primary data is usually contributed by field technical support persons, such as surveyor, engineer, and others for conventional method of survey, image along the road, computer aid drawing (cad data) as built drawing or topographical plan, and others. This study proposes an urban road mapping with optimal flight parameter and flying low for detail texture acquisition of feature. It ensures the high efficiency, low cost, short cycle, strong maneuverability, convenient operation, and others of a product. The objective of the project is to determine the optimal flight parameter in mapping out a road feature inside the road reserve with detailed digital orthophoto model (DOM) and digital elevation model (DEM). The flight parameters of unmanned aerial vehicle (UAV) and requirements for focal length effectiveness, flight planning preparation, image lap percentage, UAV altitude, and ground control point (GCP) distribution setup were outlined. The study investigated the effect of different focal length effects, GCP shape-based network (pyramid square-, square-, and linear-based networks), UAV altitude (90m, 65m, and 35m), and end lap percentage of image (90%, 80%, and 70%) on the photogrammetry-derived product. The 95m and 65m altitudes gave the lowest root mean square error (RMSE) value (±5cm horizontal and ±8cm vertical). In addition, 80% consistently showed the lowest RMSE for all end lap percentage options. Meanwhile, the pyramid square-based network recovered a total of 40% accuracy higher than square- and linear-based networks. This study could help the local authorities to implement smart road maintenance within their region.

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Journal articles on the topic 'High altitude flying'

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