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Remote Sensing Technique
Published in Ajai, Rimjhim Bhatnagar, Desertification and Land Degradation, 2022
Aircraft, unmanned aerial vehicles (UAVs), balloons, rockets and satellites have been used as platforms to carry earth observation sensors. The surveys which involve aircraft platforms for imaging are called aerial surveys. Although they are very important sometimes, such surveys are time-consuming and costly; yet they provide a wealth of information and that too at the user-defined time. They are especially suited for large-scale topographic mapping and post-disaster damage assessments. Airborne surveys have certain advantages: (i) they provide very high spatial resolution images, (ii) instrument maintenance and repairs are easy and (iii) rescheduling is simple. However, there are severe disadvantages that outweigh their advantages, e.g. a very large number of passes are required to cover the study area because of the small swath and the survey is very costly. Ground-based platforms like mobile hydraulic platforms also fall under this category as they can cover a very small area for observations. However, towers and mast form another category of ground platforms. Unmanned platforms include spacecrafts and UAVs. Space-borne remote sensing is the most popular one owing to large area coverage, repetivity and better continuity. UAVs are especially suited for remote sensing of inaccessible places where the size of the area to be covered is not very large. A special type of UAV is high-altitude long-endurance vehicles which are ultra-light remotely operated aircraft that can fly for months at a stretch at an altitude of around 20 km. Presently, imaging from UAVs like drones has become very common as these can provide quick surveys using different types of sensors, both imaging and non-imaging.
Drones in Agriculture: Soil Fertility and Crop Management
Published in K. R. Krishna, Push Button Agriculture, 2017
Based on current applications known for drones, Gogarty and Robinson (2012) classify them into micro and small drones; medium altitude drones and high altitude long endurance (HALE) drones. Medium altitude long endurance drone such as ‘Reaper’ is capable of reaching heights of 1.6 km and flying for 36 hr. without refueling. HALE drones fly at altitudes of over 9 km and for long durations during surveillance both at day and night. HALE drones are most commonly used for surveillance of international borders and military movements (Kaiser, 2006).
Autonomous Vehicles for Infrastructure Inspection Applications
Published in Diego Galar, Uday Kumar, Dammika Seneviratne, Robots, Drones, UAVs and UGVs for Operation and Maintenance, 2020
Diego Galar, Uday Kumar, Dammika Seneviratne
The following classifications, which can vary with national legal restrictions, can be taken into account when selecting a UAV for thermal imaging (Krawczyk, Mazur, Sasin, & Stokłosa, 2015): NAVs (nano air vehicles): Usually used in swarms of UAVs for radar confusion for ultra-short range surveillance. All sensors, including cameras, propulsion system, and control subsystems, need to be small (Austin, 2010).Micro UAVs: Have a close range, are portable, can be hand launched, and fly at very low altitude. Payload weight is less than 2 kg. Takeoff weight is less than 5 kg. Total power is lower than 100 W. Total time less than 1 h (Dalamagkidis, Valavanis, & Piegl, 2008).Mini UAVs: Have a close range and fly at low altitudes. Payload weight is 1–3 kg. Takeoff weight is less than 20 kg. Total power is less than 10 kW. Total time is shorter than 2 h (Dalamagkidis, Valavanis, & Piegl, 2008).Regular/small UAVs: Have medium range, medium altitude. These include launch systems. Payload weight is less than 150 kg. Takeoff weight is less than 400 kg. Total power is 10–50 kW. Total time less than 6 h.MALE (medium-altitude long-endurance) UAVs: Perform long flights at medium altitudes (Dalamagkidis, Valavanis, & Piegl, 2008).HALE (high-altitude long-endurance) UAVs: Perform long flights at high altitudes. Total flight time is 24–48 h (Dalamagkidis, Valavanis, & Piegl, 2008).
Ultra-lightweight fiber-reinforced envelope material for high-altitude airship
Published in The Journal of The Textile Institute, 2022
Rahul Vallabh, Ang Li, Philip D. Bradford, David Kim, Abdel-Fattah M. Seyam
Complex material, structural, and operational requirement continue to challenge the development of long duration, high-altitude LTA systems. None of the high-altitude airships developed so far has succeeded to remain aloft for more than a few hours (Smith et al., 2011). Three airship models (Hi-Sentinel 20, Hi-Sentinel 50, and Hi-Sentinel 80) were developed under the Hi-sentinel program, which was a tactical high-altitude, long endurance airship demonstration program conducted by US Army (Khoury & Gillett, 2004; Miller et al., 2014; Summary Report of DoD Funded Lighter-Than-Air-Vehicles, 2012). Test flights of the three models lasted for only 5 h, 3 min, and 8 h, respectively. HALE-D was another high-altitude airship, which flew in 2011, but only succeeded in rising to 9.8 km (32,000 ft) instead of flying at the intended altitude of 18.3 km (60,000 ft) (Miller et al., 2014).
Potential applications of advanced nano-composite materials for space payload
Published in Australian Journal of Mechanical Engineering, 2022
Dhaval A. Vartak, B. Satyanarayana, B. S. Munjal, K. B. Vyas, Pina Bhatt, A. K. Lal
There are many other potential orbital applications of CNTs such as a Carbon Nanotube resin mirror for an optic in a CubeSat telescope. One of the most important applications of vertically aligned CNTs is to develop a black body like venta black, useful for on-board calibration, preventing stray light from entering the telescope, improving the performance of infrared cameras of space. Other potential CNTs applications for space are: Hypersonic inflatable aerodynamic decelerators (HIADs), adaptive deployable entry and placement technology (ADEPT), high altitude long endurance vehicles (e.g., Mars and Venus airplanes), in-situ resource utilisation (ISRU), planetary rovers, parachutes, space suits, landing mechanisms, sensors, batteries (Samareh and Siochi 2017). Properties of CNTs have inspired to change the space applications in near future. However, there is often seen that there is a weak link between speculated utility and actual project demand, largely due to a lack of understanding of performance requirements and insertion opportunities for projects. There are recent advancements in manufacturing scale-up for this material, the current state of CNT maturation permits a more realistic assessment of the application of CNTs for specific functions.
A conceptual design of a solar powered UAV and assessment for continental climate flight conditions
Published in International Journal of Green Energy, 2022
Irem Turk, Emre Ozbek, Selcuk Ekici, T. Hikmet Karakoc
Many projects have also been conducted in Europe regarding high altitude, long-endurance (HALE) platforms. Solitair was developed by the DLR (German Aerospace Center) Institute of Flight Systems as part of a study carried out between 1994 and 1998. An aircraft with a wingspan of 5.2 m was built with adjustable solar panels for optimum solar radiation absorption. Flying tests were conducted successfully (André 2008). Another European study from January, 2000, to March, 2003, the Helinet project, was carried out in order to study the feasibility of a solar system and produced the 750 kg Heliplat. The production goal was to observe the world through broadband communication (Romeo et al. 2004).