[1] MENOUAR H, GUVENC I, AKKAYA K, et al. UAV-enabled intelligent transportation systems for the smart city:Applications and challenges[J]. IEEE Communications Magazine, 2017, 55(3):22-28.
[2] HOLDEN J, GOEL N. Fast-forwarding to a future of on-demand urban air transportation[EB/OL]. (2016-10-27)[2020-03-05]. https://www.uber.com/elevate.pdf.
[3] AIRBUS. Blueprint for the Sky:The roadmap for the safe integration of autonomous aircraft[EB/OL]. (2018-09-05)[2020-03-05]. https://storage.googleapis.com/blueprint/Airbus_UTM_Blueprint.pdf.
[4] THIPPHAVONG D P, APAZA R, BARMORE B, et al. Urban air mobility airspace integration concepts and considerations[C]//2018 Aviation Technology, Integration, and Operations Conference.Reston:AIAA, 2018.
[5] VASCIK P D, BALAKRISHNAN H, HANSMAN R J. Assessment of air traffic control for urban air mobility and unmanned systems[C]//8th International Conference on Research in Air Transportation, 2018.
[6] VASCIK P D, JOHN HANSMAN R. Scaling constraints for urban air mobility operations:Air traffic control, ground infrastructure, and noise[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[7] VASCIK P D, HANSMAN R J, DUNN N S. Analysis of urban air mobility operational constraints[J]. Journal of Air Transportation, 2018, 26(4):133-146.
[8] MATHUR A, PANESAR K, KIM J, et al. Paths to autonomous vehicle operations for urban air mobility[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019
[9] LASCARA B. Urban air mobility airspace integration Concepts[EB/OL]. (2019-06-11)[2020-03-05]. https://www.mitre.org/sites/default/files/publications/pr-19-00667-9-urban-air-mobility-airspace-integration.pdf.
[10] EMBRAERX. Flight plan 2030:An air traffic management concept for urban air mobility[EB/OL]. (2019-05-28)[2020-03-05]. https://daflwcl3bnxyt.cloudfront.net/m/f58fb8ea648aeb9/original/EmbraerX-White-Paper-Flight-Plan2030.pdf.
[11] 徐华翔. 亿航智能城市空中交通系统白皮书[EB/OL]. (2020-01-18)[2020-03-05]. https://www.ehang.com/app/down/%E4%BA%BF%E8%88%AA%E6%99%BA%E8%83%BD%E5%9F%8E%E5%B8%82%E7%A9%BA%E4%B8%AD%E4%BA%A4%E9%80%9A%E7%B3%BB%E7%BB%9F%E7%99%BD%E7%9A%AE%E4%B9%A6.pdf. XU H X. Ehang white paper for smart urban air mobility system[EB/OL]. (2020-01-18)[2020-03-05]. https://www.ehang.com/app/down/%E4%BA%BF%E8%88%AA%E6%99%BA%E8%83%BD%E5%9F%8E%E5%B8%82%E7%A9%BA%E4%B8%AD%E4%BA%A4%E9%80%9A%E7%B3%BB%E7%BB%9F%E7%99%BD%E7%9A%AE%E4%B9%A6.pdf (in Chinese).
[12] MUELLER E R, KOPARDEKAR P H, GOODRICH K H. Enabling airspace integration for high-density on-demand mobility operations[C]//17th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2017.
[13] NNEJI V C, STIMPSON A, CUMMINGS M (, et al. Exploring concepts of operations for on-demand passenger air transportation[C]//17th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2017.
[14] JUSTIN C Y, MAVRIS D N. Environment impact on feasibility of sub-urban air mobility using STOL vehicles[C]//AIAA Scitech 2019 Forum.. Reston:AIAA, 2019.
[15] SOMERS L A, JUSTIN C Y, MAVRIS D N. Wind and obstacles impact on airpark placement for STOL-based sub-urban air mobility[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019.
[16] SILVA C, JOHNSON W R, SOLIS E, et al. VTOL urban air mobility concept vehicles for technology development[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[17] KADHIRESAN A R, DUFFY M J. Conceptual design and mission analysis for eVTOL urban air mobility flight vehicle configurations[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019.
[18] FU M Y, ROTHFELD R, ANTONIOU C. Exploring preferences for transportation modes in an urban air mobility environment:Munich case study[J]. Transportation Research Record:Journal of the Transportation Research Board, 2019, 2673(10):427-442.
[19] SWADESIR L, BIL C. Urban air transportation for Melbourne metropolitan area[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019.
[20] CONSULTING P. The future of vertical mobility:Sizing the market for passenger, inspection, and goods services until 2035[EB/OL]. (2018-03-22)[2020-03-05]. https://www.porsche-consulting.com/fileadmin/docs/04_Medien/Publikationen/TT1371_The_Future_of_Vertical_Mobility/The_Future_of_Vertical_Mobility_A_Porsche_Consulting_study__C_2018.pdf.
[21] STANLEY M. Urban air mobility flying cars:Investment implications of autonomous urban air mobility[EB/OL]. (2018-12-2)[2020-03-05]. https://www.morganstanley.com/ideas/autonomous-aircraft.
[22] GOYAL R. Urban air mobility (UAM) market study[EB/OL]. (2018-11-21)[2020-03-05]. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20190001472.pdf.
[23] 王翔宇. 城市空中交通市场发展前景分析[J]. 航空动力, 2019(4):18-21. WANG X Y. The future of urban air mobility market[J]. Aerospace Power, 2019(4):18-21(in Chinese).
[24] JOINT D N. Concepts studies for future intracity air transportation systems:R70-2[R]. MIT:Department of AeronhUtics and Astronautics Flight Transportation Laboratory, 1970.
[25] DAVIS J E. A spot of land-the place of V/STOL aircraft in inter-and intra-city transport[C]//SAE Technical Paper Series. 400 Commonwealth Drive. Warrendale:SAE International, 1964.
[26] WOOD C. Vertical take-off aircraft for metropolitan and regional service[C]//4th Annual Meeting and Technical Display. Reston:AIAA, 1967:940.
[27] STOUT E. Study of aircraft in intraurban transportation systems:NASA-CR-1991[R]. Washington, D.C.:NASA, 1972.
[28] BRANCH M C. Urban air traffic and city planning[M]. New York:Praeger Publishers, Inc., 1973.
[29] SPECTOR S R. Helicopters-A solution to urban commercial transportation needs[C]//SAE Technical Paper Series. 400 Commonwealth Drive. Warrendale:SAE International, 1980.
[30] HARRISON S. From the archives:Los angeles airways helicopter overturns[EB/OL]. (2017-03-10)[2020-03-05]. http://www.latimes.com/visuals/photography/la-me-fw-archives-airways-helicopter-overturn-20170221-story.html.
[31] MOORE M D. Personal air vehicles:A rural/regional and intra-urban on-demand transportation system[C]//AIAA ICAS International Air and Space Symposium and Exposition:The Next 100 Years, 2003.
[32] SHEEHAN J J. Business and corporate aviation management:On-demand air transportation[M]. New York:McGraw-Hill Companies, Inc., 2003.
[33] CWERNER S B. Vertical flight and urban mobilities:The promise and reality of helicopter travel[J]. Mobilities, 2006, 1(2):191-215.
[34] TERRAFUGIA. Transition datasheet[EB/OL]. (2020-01-11)[2020-03-05]. https://terrafugia.com/wp-content/uploads/2018/10/Transition_Datasheet_RevA.pdf.
[35] LI Y. Analysis and forecast of global civil aviation accidents for the period 1942-2016[J]. Mathematical Problems in Engineering, 2019, 2019(4):1-12.
[36] KOPARDEKAR P H. Unmanned aerial system (UAS) traffic management (UTM):Enabling low-altitude airspace and UAS operations:NASA/TM-2014-218299[R]. Moffett Field:NASA Ames Research Center, 2014.
[37] KOPARDEKAR P, RIOS J, PREVOT T, et al. Unmanned aircraft system traffic management (UTM) concept of operations[C]//16th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2016.
[38] PATHIYIL L, LOW K, SOON B H, et al. Enabling safe operations of unmanned aircraft systems in an urban environment:A preliminary study[C]//International Symposium on Enhanced Solutions for Aircraft and Vehicle Surveillance Applications (ESAVS 2016). Berlin:DGON, 2016.
[39] MOHAMED SALLEH M F B, LOW K H. Concept of operations (ConOps) for traffic management of unmanned aircraft systems (TM-UAS) in urban environment[C]//AIAA Information Systems-AIAA Infotech@Aerospace. Reston:AIAA, 2017.
[40] KOPARDEKAR P. Urban air mobility:Initial reflections[EB/OL]. (2017-03-25)[2020-03-05]. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170009886.pdf.
[41] SESAR. U-space blueprint[EB/OL]. (2017-10-31)[2020-03-05]. https://www.sesarju.eu/sites/default/files/documents/reports/U-space%20Blueprint%20broch-ure%20final.PDF.
[42] ADMINISTRATION F A. Unmanned aircraft system (UAS) traffic management concept of operations V1.0[EB/OL]. (2018-06-05)[2020-03-05]. https://utm.arc.nasa.gov/docs/2018-UTM-ConOps-v1.0.pdf.
[43] HOMOLA J, DAO Q A, MARTIN L, et al. Technical capability level 2 unmanned aircraft system traffic management (UTM) flight demonstration:Description and analysis[C]//2017 IEEE/AIAA 36th Digital Avionics Systems Conference (DASC).Piscataway:IEEE Press, 2017:1-10.
[44] JOHNSON M, JUNG J, RIOS J, et al. Flight test evaluation of an unmanned aircraft system traffic management (UTM) concept for multiple beyond-visual-line-of-sight operations[C]//12th USA/Europe Air Traffic Management Research and Development Seminar (ATM2017), 2017.
[45] AWEISS A, HOMOLA J, RIOS J, et al. Flight demonstration of unmanned aircraft system (UAS) traffic management (UTM) at technical capability level 3[C]//2019 IEEE/AIAA 38th Digital Avionics Systems Conference (DASC).Piscataway:IEEE Press, 2019:1-7.
[46] CORUS. U-space concept of operations Vol1[EB/OL]. (2019-11-08)[2020-03-05]. https://www.sesarju.eu/sites/default/files/documents/u-space/CORUS%20Con-Ops%20vol1.pdf.
[47] CORUS. U-space concept of operations Vol2[EB/OL]. (2019-11-08)[2020-03-05]. https://www.sesarju.eu/sites/default/files/documents/u-space/CORUS%20Con-Ops%20vol2.pdf.
[48] SESAR. Initial view on principles for the U-space architecture[EB/OL]. (2019-07-29)[2020-03-05]. https://www.sesarju.eu/sites/default/files/documents/u-space/SESAR%20principles%20for%20U-space%20archit-ecture.pdf.
[49] ZHANG J P. UOMS in China[EB/OL]. (2018-06-11)[2020-03-05]. https://rpas-regulations.com/wp-content/uploads/2018/06/1.2-Day1_0910-1010_CAAC-SRI_Zhang-Jianping_UOMS-_EN.pdf.
[50] JARUS. JARUS Guidelines on specific operations risk assessment (SORA)[EB/OL]. (2019-03-06)[2020-03-05]. http://jarus-rpas.org/sites/jarus-rpas.org/files/jar_doc_06_jarus_sora_v2.0.pdf.
[51] 李诚龙, 屈文秋, 李彦冬, 等. 面向eVTOL航空器的城市空中运输交通管理综述[J]. 交通运输工程学报, 2020, 20(4):35-54. LI C L, QU W Q, LI Y D, et al. Overview of traffic management of urban air mobility (UAM) with eVTOL aircraft[J]. Journal of Traffic and Transportation Engineering, 2020, 20(4):35-54(in Chinese).
[52] METI. Roadmap for the application and technology development of UAVs in Japan[EB/OL]. (2019-02-01)[2020-03-05]. https://www.meti.go.jp/english/policy/mono_info_service/robot_industry/downloadfiles/uasroadmap.pdf.
[53] NAKAMURA H, HARADA K, OURA Y, et al. UTM concept demonstrations in Fukushima; requirements for UAS-port operation with different UAS operators[C]//2018 International Conference on Unmanned Aircraft Systems (ICUAS).Piscataway:IEEE Press, 2018:1295-1301.
[54] METI. UTM project in Japan[EB/OL]. (2017-08-05)[2020-03-05]. https://gutma.org/montreal-2017/wp-content/uploads/sites/2/2017/07/UTM-Project-in-Japan_METI.pdf.
[55] METI. Roadmap toward air mobility revolution[EB/OL]. (2019-01-07)[2020-03-05]. https://www.meti.go.jp/english/press/2018/pdf/1220_004a.pdf.
[56] 全权, 李刚, 柏艺琴, 等. 低空无人机交通管理概览与建议[J]. 航空学报, 2020, 41(1):023238. QUAN Q, LI G, BAI Y Q, et al. Low altitude UAV traffic management:an introductory overview and proposal[J]. Acta Aeronautica et Astronautica Sinica, 2020, 41(1):023238(in Chinese).
[57] SUNIL E, HOEKSTRA J, ELLERBROEK J, et al. Metropolis:Relating airspace structure and capacity for extreme traffic densities[C]//11th USA/Europe Air Traffic Management Research and Development Seminar (ATM2015), 2015.
[58] GHARIBI M, BOUTABA R, WASLANDER S L. Internet of drones[J]. IEEE Access, 2016, 4:1148-1162.
[59] JANG D S, IPPOLITO C A, SANKARARAMAN S, et al. Concepts of airspace structures and system analysis for UAS traffic flows for urban areas[C]//AIAA Information Systems-AIAA Infotech@Aerospace. Reston:AIAA, 2017.
[60] CLOTHIER R, WALKER R, FULTON N, et al. A casualty risk analysis for unmanned aerial system (UAS) operations over inhabited areas[C]//Second Australasian Unmanned Air Vehicle Conference, 2007:1-15.
[61] ROTHFELD R, BALAC M, PLOETNER K O, et al. Agent-based simulation of urban air mobility[C]//2018 Modeling and Simulation Technologies Conference. Reston:AIAA, 2018.
[62] QI F, ZHU X T, MANG G, et al. UAV network and IoT in the sky for future smart cities[J]. IEEE Network, 2019, 33(2):96-101.
[63] ULLAH H, GOPALAKRISHNAN NAIR N, MOORE A, et al. 5G communication:An overview of vehicle-to-everything, drones, and healthcare use-cases[J]. IEEE Access, 2019, 7:37251-37268.
[64] CHO J, YOON Y. How to assess the capacity of urban airspace:A topological approach using keep-in and keep-out geofence[J]. Transportation Research Part C:Emerging Technologies, 2018, 92:137-149.
[65] SUNIL E, ELLERBROEK J, HOEKSTRA J, et al. Analysis of airspace structure and capacity for decentralized separation using fast-time simulations[J]. Journal of Guidance, Control, and Dynamics, 2016, 40(1):38-51.
[66] ARNTZEN M, AALMOES R, BUSSINK F, et al. Noise computation for future urban air traffic systems:NLR-TP-2015-289[R]. Amsterdam:National Aerospace Laboratory NLR, 2015.
[67] VIDOSAVLJEVIC A, DELAHAYE D, SUNIL E, et al. Complexity analysis of the concepts of urban airspace design for metropolis project[C]//4th ENRI International Workshop on ATM/CNS. Tokyo:ENRI, 2015.
[68] HOEKSTRA J M, MAAS J, TRA M, et al. How do layered airspace design parameters affect airspace capacity and safety?[C]//7th International Conference on Research in Air Transportation, 2016.
[69] SUNIL E, HOEKSTRA J, ELLERBROEK J, et al. The influence of traffic structure on airspace capacity[C]//7th International Conference on Research in Air Transportation, 2016.
[70] HOEKSTRA J M, ELLERBROEK J, SUNIL E, et al. Geovectoring:reducing traffic complexity to increase the capacity of uav airspace[C]//8th International Conference on Research in Air Transportation, 2018.
[71] SUNIL E, ELLERBROEK J, HOEKSTRA J M, et al. Three-dimensional conflict count models for unstructured and layered airspace designs[J]. Transportation Research Part C:Emerging Technologies, 2018, 95:295-319.
[72] LOWRY M. Towards high-density urban air mobility[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[73] CHO J, YOON Y. Extraction and interpretation of geometrical and topological properties of urban airspace for UAS operations[C]//13th USA/Europe Air Traffic Management Research and Development Seminar (ATM 2019), 2019.
[74] MCFADYEN A, BRUGGEMANN T. Unmanned air traffic network design concepts[C]//2017 IEEE 20th International Conference on Intelligent Transportation Systems (ITSC). Piscataway:IEEE Press, 2017:1-7.
[75] MOHAMED SALLEH M F B, CHI W C, WANG Z K, et al. Preliminary concept of adaptive urban airspace management for unmanned aircraft operations[C]//2018 AIAA Information Systems-AIAA Infotech@Aerospace. Reston:AIAA, 2018.
[76] BULUSU V, POLISHCHUK V. A threshold based airspace capacity estimation method for UAS traffic management[C]//2017 Annual IEEE International Systems Conference (SysCon).Piscataway:IEEE Press, 2017:1-7.
[77] BULUSU V, POLISHCHUK V, SENGUPTA R, et al. Capacity estimation for low altitude airspace[C]//17th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2017.
[78] BULUSU V, SENGUPTA R, POLISHCHUK V, et al. Cooperative and non-cooperative UAS traffic volumes[C]//2017 International Conference on Unmanned Aircraft Systems (ICUAS).Piscataway:IEEE Press, 2017:1673-1681.
[79] BULUSU V, SENGUPTA R, MUELLER E R, et al. A throughput based capacity metric for low-altitude airspace[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[80] BULUSU V. Urban air mobility:Deconstructing the next revolution in urban transportation-feasibility, capacity and productivity[D]. Berkeley:University of California, Berkeley, 2019.
[81] KROZEL J, PETERS M, BILIMORIA K. A decentralized control strategy for distributed air/ground traffic separation[C]//AIAA Guidance, Navigation, and Control Conference and Exhibit. Reston:AIAA, 2000.
[82] CONSIGLIO M, MUÑOZ C, HAGEN G, et al. ICAROUS:Integrated configurable algorithms for reliable operations of unmanned systems[C]//2016 IEEE/AIAA 35th Digital Avionics Systems Conference (DASC). Piscataway:IEEE Press, 2016:1-5.
[83] ZHU G D, WEI P. Low-altitude UAS traffic coordination with dynamic geofencing[C]//16th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2016.
[84] BALAKRISHNAN H, CHANDRAN B. A distributed framework for traffic flow management in the presence of unmanned aircraft[C]//12th USA/Europe Air Traffic Management Research and Development Seminar (ATM2017), 2017.
[85] BRITTAIN M, WEI P. Autonomous aircraft sequencing and separation with hierarchical deep reinforcement learning[C]//8th International Conference on Research in Air Transportation, 2018.
[86] SHIHAB S A M, WEI P, RAMIREZ D S J, et al. By schedule or on demand?-A hybrid operation concept for urban air mobility[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019.
[87] ZHOU J Z, JIN L, WANG X, et al. Resilient UAV traffic congestion control using fluid queuing models[J]. IEEE Transactions on Intelligent Transportation Systems, 2020, doi:10.11091TITS.2020.3004406.
[88] BAHABRY A, GHAZZAI H, VESONDER G, et al. Space-time low complexity algorithms for scheduling a fleet of UAVs in smart cities using dimensionality reduction approaches[C]//2019 IEEE International Systems Conference (SysCon). Piscataway:IEEE Press, 2019:1-8.
[89] ROY S, HERNICZEK KOTWICZ M T, LEONARD C, et al. A multi-commodity network flow approach for optimal flight schedules for an airport shuttle air taxi service[C]//AIAA Scitech 2020 Forum.Reston:AIAA, 2020.
[90] XUE M, RIOS J, SILVA J, et al. Fe3:An evaluation tool for low-altitude air traffic operations[C]//2018 Aviation Technology, Integration, and Operations Conference.Reston:AIAA, 2018.
[91] PREVOT T, HOMOLA J, MERCER J. From rural to urban environments:human/systems simulation research for low altitude UAS traffic management (UTM)[C]//16th AIAA Aviation Technology, Integration, and Operations Conference.Reston:AIAA, 2016.
[92] BOSSON C, LAUDERDALE T A. Simulation evaluations of an autonomous urban air mobility network management and separation service[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[93] BERTRAM J, WEI P. An efficient algorithm for self-organized terminal arrival in urban air mobility[C]//AIAA Scitech 2020 Forum. Reston:AIAA, 2020.
[94] KLEINBEKMAN I C, MITICI M A, WEI P. eVTOL arrival sequencing and scheduling for on-demand urban air mobility[C]//2018 IEEE/AIAA 37th Digital Avionics Systems Conference (DASC). Piscataway:IEEE Press, 2018:1-7.
[95] PRADEEP P, WEI P. Heuristic approach for arrival sequencing and scheduling for eVTOL aircraft in on-demand urban air mobility[C]//2018 IEEE/AIAA 37th Digital Avionics Systems Conference (DASC). Piscataway:IEEE Press, 2018:1-7.
[96] PRADEEP P, WEI P. Energy optimal speed profile for arrival of tandem tilt-wing evtol aircraft with rta constraint[EB/OL]. (2018-05-18)[2020-03-05]. https://www.aere.iastate.edu/~pwei/proceedings/gncc18_vahana.pdf.
[97] PRADEEP P, WEI P. Energy efficient arrival with RTA constraint for urban eVTOL operations[C]//2018 AIAA Aerospace Sciences Meeting.Reston:AIAA, 2018.
[98] PRADEEP P, WEI P. Energy-efficient arrival with RTA constraint for multirotor eVTOL in urban air mobility[J]. Journal of Aerospace Information Systems, 2019, 16(7):263-277.
[99] BALACHANDRAN S, NARKAWICZ A, MUÑOZ C, et al. A path planning algorithm to enable well-clear low altitude UAS operation beyond visual line of sight[C]//12th USA/Europe Air Traffic Management Research and Development Seminar (ATM2017), 2017.
[100] LIU S K, ATANASOV N, MOHTA K, et al. Search-based motion planning for quadrotors using linear quadratic minimum time control[C]//2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). Piscataway:IEEE Press, 2017:2872-2879.
[101] LIU Z L, KURZHANSKIY A, SENGUPTA R. An energy-based optimal control problem for unmanned aircraft systems flight planning[C]//2017 56th Annual Conference of the Society of Instrument and Control Engineers of Japan (SICE). Piscataway:IEEE Press, 2017:1320-1325.
[102] BAHABRY A, WAN X P, GHAZZAI H, et al. Low-altitude navigation for multi-rotor drones in urban areas[J]. IEEE Access, 2019, 7:87716-87731.
[103] CHAKRABARTY A, STEPANYAN V, KRISHNAKUMAR K S, et al. Real-time path planning for multi-copters flying in UTM-TCL4[C]//AIAA Scitech 2019 Forum. Restona:AIAA, 2019.
[104] BERTRAM J, WEI P. Distributed computational guidance for high-density urban air mobility with cooperative and non-cooperative collision avoidance[C]//AIAA Scitech 2020 Forum. Reston:AIAA, 2020.
[105] CHEN J. Fast planning for joint routing and charging of autonomous drone delivery system[C]//AIAA Scitech 2020 Forum. Reston:AIAA, 2020.
[106] KOCHENDERFER M J, HOLLAND J E, CHRYSSANTHACOPOULOS J P. Next-generation airborne collision avoidance system[J]. Lincoln Laboratory Journal, 2012, 19(1):17-33.
[107] PAIELLI R A, ERZBERGER H. Conflict probability estimation for free flight[J]. Journal of Guidance, Control, and Dynamics, 1997, 20(3):588-596.
[108] PAIELLI R A, ERZBERGER H. Conflict probability estimation generalized to non-level flight[J]. Air Traffic Control Quarterly, 1999, 7(3):195-222.
[109] KUCHAR J K, YANG L C. A review of conflict detection and resolution modeling methods[J]. IEEE Transactions on Intelligent Transportation Systems, 2000, 1(4):179-189.
[110] MUELLER E R, KOCHENDERFER M. Multi-rotor aircraft collision avoidance using partially observable Markov decision processes[C]//AIAA Modeling and Simulation Technologies Conference.Reston:AIAA, 2016.
[111] MUELLER E R, KOCHENDERFER M. Simulation comparison of collision avoidance algorithms for small multi-rotor aircraft[C]//AIAA Modeling and Simulation Technologies Conference. Reston:AIAA, 2016.
[112] ONG H Y, KOCHENDERFER M J. Markov decision process-based distributed conflict resolution for drone air traffic management[J]. Journal of Guidance, Control, and Dynamics, 2016, 40(1):69-80.
[113] THANH H L N N, HONG S K. Completion of collision avoidance control algorithm for multicopters based on geometrical constraints[J]. IEEE Access, 2018, 6:27111-27126.
[114] COTTON W B. Adaptive airborne separation to enable UAM autonomy in mixed airspace[EB/OL]. (2020-01-01)[2020-03-05]. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20200000700.pdf.
[115] WEIBEL R E, JOHN H R. Safety considerations for operation of unmanned aerial vehicles in the national airspace system[J]. Transportation, 2005, 37:26-30.
[116] WASHINGTON A, CLOTHIER R A, SILVA J. A review of unmanned aircraft system ground risk models[J]. Progress in Aerospace Sciences, 2017, 95:24-44.
[117] ANCEL E, CAPRISTAN F M, FOSTER J V, et al. Real-time risk assessment framework for unmanned aircraft system (UAS) traffic management (UTM)[C]//17th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2017.
[118] LaCOUR-HARBO A L. Ground impact probability distribution for small unmanned aircraft in ballistic descent[J]. 2020 International Conference on Unmanned Aircraft Systems (ICUAS), 2020:1442-1451.
[119] PRIMATESTA S, RIZZO A, LaCOUR-HARBO A. Ground risk map for unmanned aircraft in urban environments[J]. Journal of Intelligent & Robotic Systems, 2020, 97(3-4):489-509.
[120] LaCOUR-HARBO A. Quantifying risk of ground impact fatalities for small unmanned aircraft[J]. Journal of Intelligent & Robotic Systems, 2019, 93(1-2):367-384.
[121] KIM S H. Third-party risk of mid-air collision between small unmanned aircraft systems[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019.
[122] IPPOLITO C A. Dynamic ground risk mitigation for autonomous small UAS in urban environments[C]//AIAA Scitech 2019 Forum.Reston:AIAA, 2019:0961.
[123] GRAYDON M, NEOGI N A, WASSON K. Guidance for designing safety into urban air mobility:hazard analysis techniques[C]//AIAA Scitech 2020 Forum. Reston:AIAA, 2020.
[124] GE J H, KACPRZYNSKI G, ROEMER M, et al. Automated contingency management design for UAVs[C]//AIAA 1 st Intelligent Systems Technical Conference. Reston:AIAA, 2004.
[125] PASTOR E, ROYO P, SANTAMARIA E, et al. In-flight contingency management for unmanned aerial vehicles[C]//AIAA Infotech. Reston:AIAA, 2009.
[126] FERN L, RORIE R C, SHIVELY R. UAS contingency management:The effect of different procedures on ATC in civil airspace operations[C]//14th AIAA Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2014.
[127] USACH H, TORENS C, ADOLF F, et al. Architectural considerations towards automated contingency management for unmanned aircraft[C]//AIAA Information Systems-AIAA Infotech@Aerospace. Reston:AIAA, 2017.
[128] BACULI J E, IPPOLITO C A. Onboard decision-making for nominal and contingency sUAS flight[C]//AIAA Scitech 2019 Forum. Reston:AIAA, 2019.
[129] JUNG J, NAG S. Automated management of small unmanned aircraft system communications and navigation contingency[C]//AIAA Scitech 2020 Forum. Reston:AIAA, 2020.
[130] JUNG J, RIOS J L, DREW C R, et al. Small unmanned aircraft system off-nominal operations reporting system[EB/OL]. (2020-02-20)[2020-03-05]. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20200001110.pdf.
[131] GHAZZAI H, MENOUAR H, KADRI A. On the placement of UAV docking stations for future intelligent transportation systems[C]//2017 IEEE 85th Vehicular Technology Conference (VTC Spring).Piscataway:IEEE Press, 2017:1-6.
[132] FADHIL D N. A GIS-Based Analysis for selecting ground infrastructure locations for urban air mobility[D]. Munich:Technical University of Munich, 2018.
[133] DASKILEWICZ M, GERMAN B, WARREN M, et al. Progress in vertiport placement and estimating aircraft range requirements for eVTOL daily commuting[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[134] KOHLMAN L W, PATTERSON M D. System-level urban air mobility transportation modeling and determination of energy-related constraints[C]//2018 Aviation Technology, Integration, and Operations Conference. Reston:AIAA, 2018.
[135] PATTERSON M D, ANTCLIFF K R, KOHLMAN L W. A proposed approach to studying urban air mobility missions including an initial exploration of mission requirements[C]//75th Annual Forum and Technology Display. Phoenix, AZ:Vertical Flight Society, 2018.
[136] KOHLMAN L W, PATTERSON M D, RAABE B E. Urban air mobility network and vehicle type-modeling and assessment[R]. Moffett Field, CA:NASA Ames Research Center, 2019.
[137] VASCIK P D, JOHN H R. Development of vertiport capacity envelopes and analysis of their sensitivity to topological and operational factors[C]//AIAA Scitech 2019 Forum. Reston:AIAA, 2019.
[138] YILMAZ E, WARREN M, GERMAN B. Energy and landing accuracy considerations for urban air mobility vertiport approach surfaces[C]//AIAA Aviation 2019 Forum. Reston:AIAA, 2019.
[139] JUNG J, D'SOUZA S N, JOHNSON M A, et al. Applying required navigation performance concept for traffic management of small unmanned aircraft systems[C]//30th Congress of the International Council of the Aeronautics Sciences, 2016.
[140] TEMPLIN F, JAIN R, SHEFFIELD G, et al. Requirements for an integrated UAS CNS architecture[C]//2017 Integrated Communications, Navigation and Surveillance Conference (ICNS). Piscataway:IEEE Press, 2017:1-25.
[141] PONCHAK D S, TEMPLIN F L, SHEFFIELD G, et al. Reliable and secure surveillance, communications and navigation (RSCAN) for Unmanned Air Systems (UAS) in controlled airspace[C]//2018 IEEE Aerospace Conference.Piscataway:IEEE Press, 2018:1-14.
[142] PONCHAK D S, TEMPLIN F L, SHEFFIELD G, et al. An implementation analysis of communications, navigation, and surveillance (CNS) technologies for unmanned air systems (UAS)[C]//2018 IEEE/AIAA 37th Digital Avionics Systems Conference (DASC). Piscataway:IEEE Press, 2018:1-10.
[143] KERCZEWSKI R J, APAZA R D, DOWNEY A N, et al. Assessing C2 communications for UAS traffic management[C]//2018 Integrated Communications, Navigation, Surveillance Conference (ICNS). Piscataway:IEEE Press, 2018:2D3-1.
[144] PONCHAK D S, TEMPLIN F L, SHEFFIELD G, et al. Advancing the standards for unmanned air system communications, navigation and surveillance[C]//2019 IEEE Aerospace Conference.Piscataway:IEEE Press, 2019:1-9.
[145] LI H X, ZENG H C, DOWNEY A N, et al. Cellular based small unmanned aircraft systems MIMO communications[C]//2019 Integrated Communications, Navigation and Surveillance Conference (ICNS). Piscataway:IEEE Press, 2019:1-6.
[146] BIJJAHALLI S, SABATINI R, GARDI A. GNSS performance modelling and augmentation for urban air mobility[J]. Sensors, 2019, 19(19):4209.
[147] SYD ALI B. Traffic management for drones flying in the city[J]. International Journal of Critical Infrastructure Protection, 2019, 26:100310.
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