Unmanned aircraft systems (UAS), commonly known as ‘drones’, are emerging technology with extensive applications in various domains and industries. The unique ability of UAS to collect imagery at user-defined spectral, spatial, and temporal resolutions offers new possibilities for urban applications that require rapid mapping, assessment, or management.

Recognizing a new frontier of urban applications emerging with UAS platforms, Dr. Feilin Lai (Geography alumni) and Austin Bush (EMHS researcher) as the lead authors just published a paper discussing the opportunities and challenges of UAS for urban applications that have been included in the book Urban Remote Sensing: Monitoring, Synthesis and Modeling in the Urban Environment (2nd Edition)by Wiley Blackwell (2022)

The article introduces the concept of UAS and some common types of UAS platforms and cameras onboard, followed by a discussion of a typical UAS data collection procedure, including mission planning, flight operations, and data processing. In general, the common challenges faced by UAS missions include legal regulations of air space, logistical planning, safety, privacy, social acceptance, and data protection issues. Adding to these challenges, the lack of universal regulations and/or standards for the operation of UAS in non-segregated airspace presents unique regulatory problems to UAS operators. Each UAS mission needs to be planned based on the local regulations relevant to the location and the unique mission context.

Despite that the widespread use of UAS is limited by regulations and safety concerns, the exploration of UAS applications has been initiated in research on urban location and extent, land cover and land use analyses, transportation networks and infrastructure assessments, and census-related statistics. Particularly, the article highlighted several urban applications using UAS, including disaster relief efforts, building inspections, disorder detections, and smart cities construction, along with a case study to demonstrate how UAS can be used for three-dimensional mapping of urban building structures.

Disaster management is an important component of disaster response, and UAS is increasingly being utilized as a remote sensing tool in these contexts. With UAS, disaster zones can be observed and assisted promptly, without the tremendous costs and challenges typically associated with the use of manned aircraft. For example, UAS can search for the affected population accurately and swiftly to help understand their needs (e.g., water, food, medical assistance, etc.), and therefore humanitarian relief can be more efficiently delivered.

Urban sustainability is a rising global concern regarding the increasing energy demand associated with the growing urban population. Infrastructure inspection and maintenance are necessary to maintain building energy efficiency and reduce further maintenance costs. UAS can capture building thermal patterns with infrared cameras, which can help to assess energy production and conservation of urban structures.

The physical characteristics of neighborhoods are essential information for analyzing the

effects of place on social problems. UAS can help with collecting physical disorder information (e.g., litter, unkempt lots, and building decay) at a sharp resolution without the sight-blocking issue associated with omnidirectional street imagery and temporal mismatch issues related to satellite imagery.

Smart city is an idea to integrate modern technologies to support a healthy, safe, and convenient way of urban living. In the realization of smart cities, UAS can play a role in monitoring, detecting, and predicting anomalies in urban environments and therefore safeguarding humans. Specifically, UAS can be used in traffic and crowd monitoring, 3D building mapping, and urban growth to better understand urban dynamics.

In urban areas, using UAS faces the risk of bird strikes, collisions with other aircraft, and/or impacts with people or structures on the ground. UAS can also cause a higher noise floor and unintentional jamming in an urban area, thus potentially interfering with other nearby radio signals. Based on these issues, several technical advancements have been identified that can improve the use of UAS in urban areas. Specifically, robust navigation systems should be designed to address the signal occlusion and multi-path effects caused by urban structures; more intelligent autonomous operation modes will need to be developed to account for the issue of urban obstacles; more sophisticated data processing systems that can help improve the limited performance of currently small, lightweight platforms; and automated path planning systems are urgently needed. There is still much room for the UAS technology to develop and improve for urban remote sensing. A surge of UAS applications in urban studies can be foreseen when regulations have been developed to better integrate UAS into the general airspace and when technologies have been improved for better UAS urban operations.