## 2 Architecture: The EMERGE System  
In this section, we introduce the EMERGE system and describe its architectural details from both physical/hardware and software perspectives. The EMERGE system ([[http://www.radiolabs.it/en/emerge/](http://www.radiolabs.it/en/emerge/)]([http://www.radiolabs.it/en/emerge/](http://www.radiolabs.it/en/emerge/)) accessed on 25 March 2024), or simply EMERGE, for short, is a heterogeneous platform capable of offering innovative navigation services through the integration of advanced solutions for location, communication, and cyber-security for smart vehicle equipment and distributed infrastructure dedicated to information management and service provision. Figure 1 shows a high-level overview of technologies, infrastructural components, users, and interactions between elements that form the EMERGE system. Specifically, note that the system is designed to manage and optimize various kinds of operational modes for a fleet of _smart_ vehicles, i.e., vehicles equipped with both computational resources and communication, with high-throughput 5G-based capabilities. Vehicles are assumed to start their \"operational\" daily activity from a pre-defined depot and are then allowed to move in a geographical area, according to requests or plans provided to the system by external users, to perform various types of operations. In the process, vehicles can collect data via sensors and can communicate both with each other and with a dedicated two-level infrastructure via cyber-secure protocols. Such infrastructure is organized in a hierarchical fashion, with local units of the multi-access computing type placed close to vehicles and with limited computational capabilities (to handle basic tasks), and a single, remote, ground center (named _EMERGE Ground Control_, or _EGC_ from here onward) with larger computational resources (to handle more complex tasks). Both the vehicles and local units of multi-access computing have access to cloud-based resources for data collection and processing and to satellites (multi-frequency and multi-constellation satellite positioning systems for effective positioning and geo-referencing (also known as GNSSs, such as GPS or GALILEO)). In more detail, each vehicle is equipped with both standard (e.g., tachometer, odometer) and additional (e.g., IMU, LIDAR, RADAR) sensors, advanced aggregation/processing data platforms, and multi-protocol communication. Each vehicle can be customized with different technological setups depending on two possible pre-defined _operational modes_, namely, ordinary and emergency operational modes. The vehicles are _semi-autonomous_ in the sense that they can have a driver to perform tasksthat are difficult to automate while at the same time having the ability to communicate and perform distributed tasks autonomously, without the driver's intervention. The driver can access the EMERGE network only through the vehicle, and there is no interaction between the driver's mobile device and the vehicle for EMERGE services. In terms of software architecture, the above system organization translates into the software platform in Figure 2. On one side of the figure, we observe the vehicle component: each vehicle is equipped with an _EMERGE on-board unit (OBU)_, a software/hardware unit that takes care of performing computational tasks, data collection, and analysis and implements communication with both other vehicles and the infrastructure. Such communication happens through appropriate software modules providing support to transmit, securely and reliably (by exploiting a Crypto-engine unit), over both terrestrial (LTE/5G) and satellite (e.g., Athena Fidus) protocols. On the other side of the figure, we report a description of the software units running on both edge-computing infrastructure and EMERGE Ground Control (EGC).