Techniques to Make Drones Operate at High Altitudes

A communication control system for high altitude long endurance (HALE) aircraft like stratospheric drones to ensure complete coverage of their communication beacon signal over the ground. The system adjusts the number of transmission elements in the phased array antenna based on the aircraft altitude. This compensates for the changing link budget and beam angle at different altitudes to ensure the beacon can reach the entire coverage area.

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This paper examines the approaches to control Unmanned Aerial Vehicles (UAVs) concerning energy conservation and sustainability at high altitudes long ranges. The work integrates research development activities UAVs environmental footprint by evaluating eco-friendly material selections, noise mitigation methods, life cycle assessments toward greening UAV operations, as a fleet requires operation considerations. Furthermore, autonomous navigation systems, sensor integration, data processing, AI, ML are integrated. Hence, sophisticated emphasis of this evaluation is placed on sustainable design strategies considerable measures reduce pollution for environmentally-friendly operation. More specifically, includes review construction materials, emission reduction well an extensive reference systems. techniques, sensors optimal navigation, brief real-time processing techniques. In addition, innovative use artificial intelligence, machine learning, deep learning optimization missions evaluated, enhancing their efficiency reliability in real-world conditions. Finally, UAVs analyzed conclus... Read More

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In this paper, we investigate a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS)-assisted non-orthogonal multiple access (NOMA) communication system where the STAR-RIS is mounted on an unmanned aerial vehicle (UAV) with adjustable altitude. Due to severe blockages in urban environments, direct links from base station (BS) users are assumed unavailable, signal transmission realized via STAR-RIS. We formulate joint optimization problem that maximizes sum rate by jointly optimizing UAVs altitude, BS beamforming vectors, phase shifts, while considering Rician fading channels altitude-dependent factors. To tackle maximum achievable problem, adopt block-wise framework employ semidefinite relaxation gradient descent methods. Simulation results show proposed scheme achieves up 22% improvement significant reduction bit error (BER) compared benchmark schemes, demonstrating its effectiveness integrating UAV NOMA networks.

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In both scientific and industrial fields, there has been a notable increase in attention toward High-Altitude Pseudo-Satellites (HAPS) recent years. This surge is driven by their distinct advantages over traditional satellites Remotely Piloted Aircraft Systems (RPAS). These benefits are particularly evident critical areas such as intelligent transportation systems, surveillance, remote sensing, traffic environmental monitoring, emergency communications, disaster relief efforts, the facilitation of large-scale temporary events. review provides an overview key aspects related to propellers propulsion systems HAPS. Firstly, analysis proposed literature or employed HAPS presented, focusing on technical challenges advancements this emerging field. Given that remain most efficient propulsor for applications, discussion then shifts fundamental principles propeller theory, followed innovative design methodologies intended high-altitude operations concerning evaluating performance. The unique atmospheric conditions at high altitudes result characteristics stratospheric airships compared conve... Read More

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A lightweight, high-efficiency solar cell for use in stratospheric flight vehicles that converts ultraviolet light into electricity. The solar cell has a unique structure with wavelength conversion layers on the front surface. The outermost layer converts UV light into visible light. An inner layer converts some visible light into longer wavelengths. This allows efficient use of high-UV stratospheric sunlight. The total thickness is less than 500g/m2 for weight savings. The solar cell can be integrated into stratospheric flight vehicles for extended flight times and distances.

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Unmanned aerial vehicle (UAV) system that enables sustained flight through power management and energy harvesting. The system comprises a solar-powered UAV with a battery pack that can store excess energy during the day. The battery pack is charged through a solar array and a power tracker. When the battery reaches full charge, it can be used to power the motor for ascent to a higher altitude. After sunset, the UAV can descend to a lower altitude using stored energy from the battery pack, employing advanced loitering techniques to minimize energy consumption. The system maintains optimal battery temperature while preventing overcharging and overheating.

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Air supply system for fuel cell powered aerial vehicles that ensures stable and optimized air supply to the fuel cell stack at altitude. The system compresses air from the aerial vehicle's air intake using the vehicle's drive motor, conditioning it in a chamber before supplying to the fuel cell. An opening/closing valve selectively allows air intake based on flight altitude. This provides air with optimal temperature/pressure for fuel cell operation at altitude. The drive motor compression also reduces external power needs. The air chamber stabilizes air properties versus outside temperature changes.

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Enabling reliable operation of aircraft electrical converters at high altitudes with increased cosmic radiation by actively controlling the semiconductor device temperatures. The converter controller receives altitude signals and adjusts the switching patterns of the semiconductor devices to increase their junction temperatures at high altitudes. This compensates for the increased radiation-induced reliability issues at altitude. By intentionally increasing device temperatures, it allows higher power handling capability at altitude without de-rating the converter voltage.

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Advances in drone technology have significantly improved their applications, but traditional designs often limit flexibility and efficiency different operating conditions [5]. This paper presents the concept of Xtreme reconfigurable drone, an innovative system that can dynamically change its layout flight to adapt mission requirements. The features variable-pitch adjustable-diameter propellers made flexible materials controlled by a sophisticated control module [7]. uses real-time sensor data machine-learning algorithms maintain transition balance stability [6]. Additionally, chassis has standard gearbox allows torque RPM adjustments, optimizing performance on demand Our approach incorporates origami-inspired folding techniques minimize number required actuators, thereby improving systems [10]. Prototyping included computer-aided design (CAD) modeling, 3D printing, integrating advanced electronics. Extensive testing was conducted evaluate drones various configurations environmental [3]. results showed flexibility, stability, maneuverability compared drones [1], [4]. represents ... Read More

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Reducing the wing platform area of stabilizers through innovative design offers decreased structural weight, increased aerodynamic performance, fuel efficiency, and stealth characteristics. Further, examining characteristics unmanned aerial vehicles at higher angles attack is essential for enhancing their adaptability, operational effectiveness. This study mainly investigates performance sections with lesser areas leading-edge tubercles compared to conventional attack. Numerical simulations were performed by solving Reynolds-averaged NavierStokes equations k shear stress transport turbulence model using ANSYS Fluent, covering from 0 26 in 2 increments Reynolds numbers ranging 5 105 6 106 assuming constant section zero swept angle along span. The coefficients numerical validated data obtained a six-component external pyramidal balance attached low-speed wind tunnel, they compare well. flow field over examined vorticity, turbulent kinetic energy, coefficient pressure plots. reveals that has lift sustained same large after stall stabilizer, although slightly noticed til... Read More

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Optimizing long-duration flight of UAV clusters working together to increase flight time and range of UAVs in complex terrain environments. The method involves using natural winds to enable unpowered flight or reduce power needs. UAVs cluster together, with a lead UAV planning flight paths. They build airflow models based on geographical indicators. The initial flight path airflow is expanded iteratively to create a full airspace model. Comparing with typical flight plans finds optimal paths for unpowered flight. This allows UAVs to glide efficiently with natural winds, maintain stability, and extend endurance.

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Solar-powered unmanned aerial vehicles (UAVs) can ascend to higher altitudes during the day when fully charged and then glide down to lower altitudes at night to conserve stored energy. This allows the UAVs to use excess solar power to climb to higher altitudes when the batteries are full rather than just wasting energy. The climb-up and glide-down process delays battery use until later in the night when there is less time to charge again.

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A UAV control method and system to improve cruising capability by optimizing flight parameters based on weather forecasts along the route. The method involves obtaining weather information and positioning data, determining the weather trend along the route, and adjusting flight parameters like thrust, speed, and angle to compensate for weather conditions. This allows the UAV to better match power consumption to expected weather changes, improving efficiency and endurance.

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Calibrating the altitude readings of a small stereo vision device on a UAV to accurately measure height at any altitude above ground. The method involves recording stereo vision altitude against another sensor during ascent and then adjusting the altitude readings using the calibration data. This extends the reliable altitude range beyond the stereo vision device's normal capabilities.

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An altitude control system for high-altitude unmanned aerial vehicles (UAVs) that compensates for thermal expansion mismatch. The system has a compressor assembly with a steel driveshaft inside an aluminum housing. A flexible plate applies preloading force to the bearings that change with temperature. This compensates for differential expansion rates between the steel shaft and aluminum housing to prevent bearing failure. The flexible plate moves closer to the housing as it expands, keeping the bearings loaded.

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A high-lift unmanned aerial vehicle (UAV) with adaptive flight control for operating in strong winds. The UAV has a tandem wing configuration, ducted fan, vector fan, and tether. It uses a self-adaptive flight control system to adjust fan speeds, fan deflection angles, and cable tension based on real-time wind data to maintain stability in windy conditions. The UAV can resist level 9 winds, expanding its usability compared to conventional UAVs.

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Long-stay flight planning for unmanned aerial vehicles (UAVs) that maximizes flight time by leveraging natural winds. The method involves building airflow models based on geographic indicators, comparing them to initial flight data, and expanding the models dynamically as the UAV flies. This allows the UAV to plan efficient flight paths using natural winds rather than relying solely on its own power.

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Drone with retractable wings that automatically deploy at altitude to improve efficiency and maneuverability. The drone has a rotary wing and retractable fixed wings. A control device deploys the fixed wings when the drone reaches a certain altitude. This allows efficient horizontal flight with the rotary wings at low altitude, then deploys the fixed wings for high altitude cruising. It avoids drag and wind interference during takeoff and landing with the rotary wings alone.

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Hybrid flight method for tilt-rotor drones that combines vertical takeoff/landing of a multirotor with fixed-wing flight efficiency. The method involves calculating the tilt angle required to transition between vertical and horizontal flight modes at waypoints. This allows the drone to optimize its flight path by switching between multirotor and fixed-wing flight modes at waypoints to reduce distance, time, and energy consumption. The tilt angle is calculated based on factors like wind speed, target location, and drone capabilities. By intelligently switching between multirotor and fixed-wing flight modes, the drone can fly more efficiently and accurately.

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Control method for unmanned aerial vehicles (UAVs) to enable stable flight in environments with varying atmospheric conditions like temperature and pressure. The UAV acquires atmosphere information like temperature, pressure, and gas type. Based on this, it determines flight parameters specifically for that environment. It then adjusts the UAV's thrust output using these environment-specific parameters. This allows the UAV to compensate for changing atmospheric conditions and fly more stably in environments like high-temperature or high-pressure spaces.

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