Urban Remote Sensing. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

Автор: Группа авторов
Издательство: John Wiley & Sons Limited
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Жанр произведения: География
Год издания: 0
isbn: 9781119625858
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are conducted. The rapid development of UAS technology in recent years has led to a present regulatory challenge facing government officials. How do we allow UAS technology to become an integral tool in a wide variety of industries while also not creating new problems related to the increased presence of UAS in civil airspace? Different countries/states/provinces/regions have UAS regulations that are often structured with similar intentions, especially if they are regional neighbors. However, there is still a wide discrepancy in the specific details of these regulations from one regulatory body to another. Although the specific details of one country’s UAS regulations may differ from the rest, there are many common topics that the regulations are focused on. These regulatory topics generally include restrictions on flight altitude, max UAS speed during flight, which airspaces UAS can be operated within, design limitations of UAS platforms, and other potential risks posed to the public (Al Shibli, 2015). The use of UAS in civil airspace presents a host of potential risks and problems, such as surveillance and privacy concerns (West and Bowman, 2016), noise disturbances to the public (Wallace et al., 2018), and the general lack of universally standardized safety features in contemporary UAS models (Plioutsias et al., 2018). For these reasons, it is highly advised for UAS operators to look at the regulations from the specific country before conducting any aerial operations.

      3.6.2 OPERATIONAL CHALLENGES

      Operationally, accomplishing a UAS mission is no simple task. Implementing UAS missions in urban areas with intensive human activities takes efforts to address a host of issues, such as legal, safety, ethical procurement and partnerships, privacy and data protection, data transparency, informed consent, and community engagement for humanitarian purposes (Gilman, 2014). Major safety hazards of using UAS in urban areas may include bird strikes, collisions with other aircraft, and/or impacts with people or structures on the ground. Large structures like skyscrapers or transmission towers can impede the communication between the aircraft and the GCS, diminishing navigational performance by shielding the UAS from GPS satellites and increasing multipath reflection (Clothier and Walker, 2015). Low‐altitude UAS operations can be even more challenging under the presence of obstacles like trees, slopes, towers, and powerlines. Therefore, there is a need for UAS manufacturers to enrich the pool of obstacles that the safe autonomous mode can recognize and avoid in‐flight (Ippolito et al., 2016).

      UAS can also cause a higher noise floor and unintentional jamming in an urban area (Watkins et al., 2020). In some countries, such as the United States, there are significant concerns from the public regarding personal privacy and one’s reasonable expectation of it. Therefore, legal and ethical issues need to be addressed in any UAS mission, especially those operating in higher risk areas, such as urban areas (Skrzypietz, 2012). Therefore, a proficient crew of knowledgeable personnel is always essential for the deployment of UAS in a safe, legal, and ethical manner. The skillsets for the UAS team to ensure safe operations generally include (but are not limited to) a strong understanding of situational awareness, proper assignment of roles, recognition of UAS pilot fatigue, the use of a risk mitigation procedure, knowledge of UAS and all related components, and effective communication with all other crew members.

      3.6.3 SPATIAL COVERAGE AND DATA QUALITY

      Despite that a UAS supports the collection of high‐resolution imagery with elevation information, it is hard to cover a large mapping region given the limited battery life and the number of batteries that can be carried by the crew. Particularly, the FAA restricts the number of spare lithium‐ion and lithium metal batteries each passenger can carry on a flight (Federal Aviation Administration, 2013), which should be considered when air travel is necessary to complete a UAS mission. The quality of UAS products is another important consideration in research studies. Unlike conventional aerial photography or space imaging technology, UAS mapping is achieved through photogrammetrical methods building a model that defines the spatial relationships within the images and then stitches them together. Post‐processing is usually needed to make sure the UAS products meet the research‐specific requirements on geometric accuracy, radiometric accuracy, spatial extent, spatial resolution, temporal resolution, etc. Using control points is an effective way to enhance the geometric correction of the UAS imagery. It has been found that the horizontal and vertical accuracy of UAS photogrammetry results can be narrowed down to centimeter‐level with certain amounts of GCPs (Devriendt and Bonne, 2014). With accurate locational data, reliable DEM products can be derived from UAS point clouds through classification (Day et al., 2016).

      Overall,