[1] Alex F. Drones are everywhere. Get used to it[J]. Time, 22, 24-25(2018).

[2] Stolaroff J K, Samaras C, O'Neill E R et al. Energy use and life cycle greenhouse gas emissions of drones for commercial package delivery[J]. Nature Communication, 9, 1-13(2018).

[3] Floreano D, Wood R J. Science, technology and the future of small autonomous drones[J]. Nature, 521, 460-466(2015).

[6] Mohamed N, Al-Jaroodi J, Jawhar I et al. Unmanned aerial vehicles applications in future smart cities[J]. Technological Forecasting and Social Change, 1-15(2018).

[7] Kopardekar P. Unmanned Aerial System ( UAS) Traffic Management (UTM): Enabling low-altitude airspace and UAS operations[J]. NASA Center for Aerospace Information.(2014). http://www. nasa. gov

[8] . U-Space Blueprint., 2-5(2017).

[10] Mohammed S M F B, Chi W C, Wang Z K et al. Preliminary concept of adaptive urban airspace management for unmanned aircraft operations[J]. AIAA SciTech Forum. Kissimmee, Florida(2018).

[14] 1939.1-Standard for a framework for structuring low altitude airspace for unmanned aerial vehicles (UAV) operations[J](2019). https://sagroups.ieee.org/1939-1/

[18] Handler C H. New York state creates nation's first air corridor for unmanned aerial vehicles[J](2018). https://suffolklaw.com/new-york-state-creates-nations-first-air-corridor-for-unmanned-aerial-vehicles/

[19] . Skyways: Urban air delivery explored[J](2017). https://www.airbus. com/newsroom/news/en/2017/11/skyways-urban-air-delivery-explored.html

[27] Colomina I, Molina P. Unmanned aerial systems for photogrammetry and remote sensing: A review[J]. ISPRS Journal of Photogrammetry and Remote Sensing, 92, 79-97(2014).

[29] Oliveira H C, Guizilini V C, Nunes I P et al. Failure detection in row crops from UAV images using morphological operators[J]. IEEE Geoscience Remote Sensing, 15, 991-995(2018).

[30] Ammour N, Alhichri H, Bazi Y et al. Deep learning approach for car detection in UAV imagery[J]. Remote Sensing, 9, 1-15(2017).

[31] Crommelinck S, Bennett R, Gerke M et al. Review of automatic feature extraction from high-resolution optical sensor data for UAV-based cadastral mapping[J]. Remote Sensing, 689, 1-28(2016).

[32] Yao H, Qin R J, Chen X Y. Unmanned aerial vehicle for remote sensing applications: A review[J]. Remote Sensing, 1443, 1-22(2019).

[34] Liao X H, Xu C C, Yue H Y. Enable UAVs safely flight in low-altitude: A preliminary research of the public air route network of UAVs[J]. International Conference on Unmanned Aircraft Systems (ICUAS), Atlanta, GA, USA, 959-964(2019).

[35] Caltagirone L, Scheidegger S, Svensson L et al. Fast LiDAR-based road detection using fully convolutional neural networks[C]. IEEE Intelligent Vehicles Symposium (IV). Redondo Beach, CA, USA, 1019-1024(2017).

[36] Chen Y, Fan R S, Yang X C et al. Extraction of urban water bodies from high-resolution remote-sensing imagery using deep learning[J]. Water, 10, 1-20(2018).

[37] Nijhawan R, Sharma H, Sahni H et al. A deep learning hybrid CNN framework approach for vegetation cover mapping using deep features[J]. 13th International Conference on Signal-Image Technology and Internet-Based Systems, Jaipur,India, 192-196(2017).

[38] Gilani S A N, Awrangjeb M, Lu G. Fusion of LiDAR data and multispectral imagery for effective building detection based on graph and connected component analysis[J]. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XL-3/W2, 65-72(2015).

[40] Bruijnen D, van Helvoort J, van de Molengraft R. Realtime motion path generation using subtargets in a rapidly changing environment[J]. Robotics and Autonomous Systems, 55, 470-479(2007).