# The Development of an Advanced Air Mobility Flight Testing and Simulation Infrastructure
## 1 Introduction
There are many other projects, such as the \"European UTM testbed for U-space\" (EuroDRONE) [34], the \"d-flight internet of drones environment\" (DIODE) [35], Uspace4 UAM [36], and the \"validation of U-space and its services by tests in urban and rural areas\" (VUTRA) [37], concerning testing of the U-space concept, safe integration, safe operations, and demonstrating U-space service capabilities focusing on various use cases. There are also research efforts focusing on developing a simulation environment for testing and evaluating the envisioned systems for the AAM concept. One of them is NASA's \"flexible engine for fast-time evaluation of flight environments\" (Fe\({}^{3}\)), which is an evaluation tool for high-density low-altitude air traffic operations with a fast time simulation capability [38]. The Fe\({}^{3}\) simulator enables a testing environment for UASs and manned aviation operations with weather uncertainty and communication, navigation, and sensor impacts, along with conflict resolution services. Boeing's SkyWay simulator, which is an integrated ATM/UTM simulator for autonomous operations, is used especially for testing contingency management procedures in the Galician SkyWay project [39; 40]. The SkyWay simulator also includes a detect-and-avoid feature for UASs to avoid collisions. Furthermore, a simulator named U-Sky was developed by Boeing, and it mainly focuses on the network perspective of AAM and provides an environment for testing advanced UTM services in a dense traffic environment and evaluating them through numerous metrics related to safety, efficiency, workload, and so forth [41; 42]. Airbus UTM's simulator USim provides a fast-time simulation environment for UAS traffic, including a set of UTM services focusing on demand-capacity balancing, strategic conflict resolution, strategic planning, and airspace assessment through metrics such as safety, efficiency, and fairness [43]. Finally, Indra's UTM ecosystem provide features such as real-time operation monitoring, data flow between stakeholders, and conflict detection and resolution [44]. The considered UTM ecosystem consists of two parts: UTM Hub, which is used for the digital coordination of every element within the system, and UTM Connect, where the individual operations are connected to the UTM Hub. The Air Mobility Urban-Large Experimental Demonstration (AMU-LED) is one of the very large demonstration (VLD) projects supported by SESAR JU [45]. AMU-LED aims to provide an integration of UAM with traditional aviation, develop and test advanced U-space services and a system-wide contingency management concept that is defined, test both centralized and decentralized UAM architectures, and validate all defined concepts via real and simulated flight trials to pave the way for a future AAM concept. Finally, AMU-LED examines the social acceptance of the UAM concept during these demo flights. This paper focuses on the technology and infrastructure development efforts for testing and demonstrating the AAM concept in action by setting system requirements, building a co-simulation environment, deciding on the vehicles and simulators to be used, developing advanced U-space services, and defining use cases and scenarios. The main novelty of the developed infrastructure is the ability to accommodate real and simulated flights at the same time and analyze their interactions. The system provides real operational experience of AAM via real platforms and an AAM simulator that presents a realistic passenger experience for the air taxi concept, while providing scalability for such operations by including numerous simulated flights. Additionally, the development of automated advanced U-space services and their integration with the operations, by considering both pre-flight and in-flight stages and the coordination between those services, is an important contribution of this study.