With the exponential market increase in mini-and micro-drones, this technology became available for anybody around the world. Therefore, the possibility of using drones as weapons represents a danger in both the civil and military domains. In the last years, a lot of programs have been initiated to identify cost-effective measures for detection, classification, tracking and neutralization of this type of threat. In a prospective approach to mitigate these risks, the French-German Research Institute of Saint-Louis (ISL) is studying since the past ten years the technical responses that can be provided for the detection, identification, localization and tracking of small-sized aerial drones, in a variety of operational scenarios and contexts of use. In this paper, we will summary the main ISL results in this domain. Over the time, ISL participated in a lot of joint trials allowing to test acoustical and optical detection system in different operational scenarios and for a great variety of types of drones. The collected images form a database of almost 1 million of images of drones in flight at different scales, with different backgrounds and at different wavelengths (Vis, SWIR). This database is of great importance for the development of detection/localization/tracking algorithms for conventional or AI-based techniques.