Advances in Surveillance and Detect and Avoid for Unmanned Aircraft Systems and Advanced Air Mobility (2025)

In the latest years, sense and avoid (SAA), or detect and avoid (DAA), has represented one of the main roadblocks to the integration of unmanned aircraft systems (UAS) operations. At the same time, new operational scenarios such as the ones envisaged in Advanced and Urban Air Mobility (AAM/UAM) have challenged traditional airspace surveillance paradigms and approaches. In this framework, this lecture outlines and reviews architectures, technologies, and algorithms for SAA, as well as recent technological advances in surveillance for AAM. First, basic SAA definitions and taxonomies are discussed. Ground-based/airborne and cooperative/non-cooperative architectures are covered. The SAA process is dissected into its fundamental tasks, which are discussed in details. Different sensing algorithms and technologies are presented, including radar and optical systems. Potential and challenges of multi-sensor-based systems and data fusion are pointed out. Techniques for conflict detection, and approaches for remotely operated or autonomous avoidance are introduced. The tutorial analyzes recent trends such as the adoption of Artificial Intelligence (AI) and of distributed sensing approaches, and ends with an overview of current perspectives relevant to SAA for UAS integration in the Air Traffic Management (ATM) system and in the framework of UAS Traffic Management (UTM) / U-Space and Advanced/Urban Air Mobility. Links with manned aviation are covered too.