Techniques to Make Drones Operate at High Altitudes

A battery-powered flying vehicle that optimizes flight control based on the charging speed of the battery. The vehicle has a battery charged by an external power supply, and a flight control system that adjusts flight parameters like speed and altitude based on the charging rate. This allows the vehicle to balance flight capabilities with battery charging needs. For example, if the battery is charging quickly, the vehicle can fly faster and higher, but if charging is slow, it may need to conserve energy by flying slower and lower.

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Enabling user equipment (UE) like drones to seamlessly switch between terrestrial and aerial cells in a mobile communication system. The method involves the UE dynamically adjusting frequency priority for cell reselection based on altitude, allowing it to efficiently move between ground and sky cells. The network also provides specific tracking areas and frequencies for aerial cells above a threshold altitude. This prevents conflicts between ground and sky cells and enables the UE to properly reselect cells as it transitions between terrestrial and aerial environments.

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Flight controller for aerial vehicles that takes into account current environmental conditions to improve performance and avoid unachievable motor inputs. The flight controller receives environmental data from sensors, adjusts motor limits based on that data, and then converts flight inputs to motor commands that stay within the adjusted limits. This allows the aerial vehicle to adapt to changing conditions like air pressure and temperature without exceeding its capabilities.

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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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Modular payload system for high altitude drones that enables better payload equipment integration for greater precision in aiming while reducing mass and volume. The payload module includes a casing, a support structure, optical equipment, and a mirror. The support structure positions the optical equipment and mirror inside the casing. The mirror is mounted on a swivel to aim the camera view. The mirror swivel range can be offset from a centered reference position to provide flexibility. The modular payload design allows efficient integration of the optics and mirrors for aiming with reduced size and weight compared to fixed line-of-sight systems.

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High-altitude endurance unmanned aircraft (HALE UAVs) are used to augment and interdict satellite communications and surveillance. The HALE UAVs can fly at 65,000 feet, where the atmosphere is thin and clear, providing a stable, high vantage point. One use is GPS signal augmentation, where a fleet of HALE UAVs receive GPS signals and rebroadcast them to improve coverage. Another use is satellite sensor interdiction, where HALE UAVs track satellites and direct lasers to blind their sensors.

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Method for autonomously adjusting the flight trajectory of a UAV to mitigate the impact of meteorological conditions on visibility and safety. The method involves calculating the optimal flight path based on real-time cloud layer information and onboard camera images. This allows the UAV to avoid thick clouds that could obstruct visibility and pose safety risks. The UAV's onboard computer analyzes the cloud data and images to determine if adjustments are needed. If so, it generates new flight commands to maneuver the UAV away from dense clouds while still maintaining safety.

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Intelligent control device for unmanned aerial vehicles (UAVs) that uses sensors to measure wind speed and direction around the UAV, and then adjusts components like wings, tails, and vents in real-time to optimize flight efficiency by manipulating the UAV's flow field. The device has anemometers on the top surface, sensors inside rotating seats, converters to transmit data, and a controller. The UAV has features like wings, tails, and vents that can be actuated to change the flow field. This allows the controller to receive wind data and actively adjust the UAV's shape to adapt to wind conditions and improve flight performance.

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A method for controlling the flight height of a drone to mitigate the impact of wind gusts on stability and prevent sudden altitude drops. The method involves monitoring wind gusts using sensors and predicting the gust's impact on the drone's flight dynamics. Based on the predicted gust effect, the drone adjusts its flight control surfaces like ailerons and elevators to counteract the gust forces and maintain stable altitude. This active gust mitigation technique improves drone flight safety and reduces altitude fluctuations during gusty conditions.

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A method for stable height control of drones in complex weather conditions using multi-sensor fusion. The method involves combining data from multiple sensors like GPS, barometer, and lidar to accurately determine the drone's height in adverse weather. This fused height information is then used as feedback in a PID control loop to maintain stable flight altitude in challenging weather conditions where individual sensor data may be unreliable.

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Planning optimal takeoff and landing trajectories for flexible aircraft like long endurance drones that account for the aircraft's flexibility. The method involves modeling the aerodynamics, engines, atmosphere, and structural dynamics, then optimizing the trajectory using genetic algorithms to find the best takeoff and landing paths that minimize fuel consumption while satisfying constraints like maximum flexural strain and stability margins.

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An air-cooled fuel cell freeze-protection system for drones includes a heated air source, such as a combustion heater, that provides warm air to the fuel cell. The system also includes a compressor to pressurize the air delivered to the fuel cell. This warm, pressurized air prevents freezing and enables the fuel cell to operate in cold weather and at high altitudes.

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Adaptive wind estimation, trajectory generation, and flight control for aerial systems like drones that can compensate for wind disturbances without using dedicated wind sensors. The method involves estimating wind components based on aerodynamic drag identification during still-air flight. This allows generating feasible trajectories accounting for estimated winds. Motor and thrust commands are then generated using CG and attitude control to follow the wind-compensated trajectory. The approach leverages the motion of the aircraft itself rather than wind sensors, using onboard computing power.

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An advanced airborne meteorological system that uses unmanned aerial vehicles (UAVs) equipped with infrasound sensors to improve weather forecasting. The UAVs are made of lightweight foam materials with extendable wings to allow flight at different altitudes. They are fitted with infrasound sensors and other weather instruments to measure parameters like wind shear, seismic waves, magnetic storms, and severe weather.

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Optimizing flight patterns for unmanned aerial vehicles (UAVs) like high altitude long endurance solar-powered aircraft to enable efficient and safe flight in varying wind conditions. The UAVs transition between a D-loop and figure-eight loop pattern based on wind speeds. In low winds, they fly D-loops. As wind speeds exceed 40% of flight speed, they transition to figure-eight loops with gradual banking maneuvers. This allows staying close to the ground station while minimizing turn rate and bank angle. If winds drop below 40%, they exit figure-eight loops and return to D-loops.

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Communication terminal device for unmanned aerial vehicles that can dynamically adjust their antenna beam width to avoid interference from nearby ground base stations when flying at higher altitudes. The device has an altimeter to measure altitude. When altitude exceeds a threshold, the device switches to directional antenna mode.

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Unmanned aerial vehicle (UAV) that increases flight height by using dual-polarized antennas oriented in two perpendicular directions. The UAV has a horizontal antenna to transmit and receive signals over long distances along the horizontal plane and a vertical antenna to compensate for the weaker vertical polarization signals. This allows the UAV to achieve much higher vertical flight heights than a traditional UAV with only vertical antennas.

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A flight control method for solar-powered drones that enables them to autonomously seek and ascend on natural thermal updrafts to extend range and altitude beyond what solar power alone provides. The method involves using an extended Kalman filter to accurately judge the position and status of thermal updrafts in the air. The drone then flies towards the updraft center to climb altitude and convert the airflow energy into potential energy for storage. This allows the drone to leverage natural thermal energy to extend range and altitude beyond what solar power alone provides.

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Flight path optimization for high altitude long endurance of unmanned aerial vehicles (UAVs) using regenerative fuel cells and solar cells to enable continuous operation in the stratosphere. The method involves analyzing consumed/generated hydrogen and oxygen on preset flight paths through simulations to find the most efficient one. This is done by modeling the fuel cell and solar systems, simulating flights at different altitudes, and comparing hydrogen/oxygen needs.

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Optimizing flight time of drones by dynamically adjusting propeller speeds based on environmental conditions using onboard sensors. The drone has rotatable propellers that can rotate up to 90 degrees to adjust thrust direction. This allows the drone to ascend higher and stay airborne longer by optimizing lift. The drone also has sensors like wind direction, speed, and drone orientation to automatically adjust fixed and rotatable propeller speeds accordingly. This further enhances flight time by adapting to wind conditions and drone movement.

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High-altitude long endurance (HALE) drone design that can carry a substantial payload for extended periods above a target location. The drone has a large upper enclosure filled with a low-density gas like helium or hydrogen that makes it buoyant. This allows the drone to offset its weight and carry a heavy payload. The gas-filled enclosure is positioned above the drone's horizontal plane of contra-rotating propellers. This configuration enables the drone to remain stationary for weeks or months at high altitude like a stratospheric platform for applications like long-term aerial observation or telecommunications relays.

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Controlling unmanned aerial vehicles (UAVs) and cruise missiles to efficiently use tropospheric updrafts to extend flight duration and range without engines. The method involves modeling the thermally-generated ascending airflow, determining if the UAV is in an updraft region, and using a control law that allows altitude and speed reduction but not increase when in an updraft. This enables the UAV to climb using the updraft's energy, then glide using potential energy when in descending or forward flow. The UAV shuts off engines when in an updraft.

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UAV flight control system and method that optimizes UAV path planning to improve efficiency and extend range by leveraging real-time building wind data and a city air duct network. The UAV has a processor, route optimization subsystem, and wind sensors. It obtains building wind data, establishes an air duct network, and selects the best route to a destination using this information. It also adjusts propeller angles and speeds based on crosswinds. The UAV can fly through buildings, avoid crosswinds, and optimize cruise altitude for weather conditions.

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An innovative method and system to launch long endurance solar powered unmanned aerial vehicles (UAVs) using lighter-than-air aircraft. The UAV is attached to a tether on the lifting surface and suspended below the lighter-than-air craft. The tether is released at altitude and the UAV spirals up into free flight. This allows launching high altitude UAVs using a lighter-than-air craft to minimize structural weight, enabling long endurance flight.

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