Fraunhofer Institute for High Frequency Physics and Radar Techniques FHRRadar, electronic warfare, and communications are three important functions of modern multifunctional high-frequency systems (RF). In the EU project CROWN, a demonstrator was developed that unites these functions on a single aperture. Fraunhofer FHR developed a novel resource management for this purpose.
Protection against drone attacks is essential for the security and infrastructure of a country. The project “European active electronically scanned array with Combined Radar, cOmmunications, and electronic Warfare fuNctions for military applications,” short CROWN, makes a decisive contribution to European security. The system for drones and combat aircraft combines three core functions: radar, communication, and electronic warfare. CROWN will enable all these functions to be performed simultaneously.
The combination of these functions in a compact and lightweight device is so far unique in a European system. On behalf of the European Commission under the Preparatory Action on Defence Research (PADR) 2019, Fraunhofer FHR has been cooperating since 2021 with ten European partners from industry and research institutions. In doing so, the researchers also demonstrated how a resilient EU supply chain can be built to strengthen technological sovereignty. After the completion of CROWN, the successor project SCEPTER started in 2025, in which Fraunhofer FHR is again a major contributor.
Resource Management Augmented With Antenna Share
Fraunhofer FHR developed the resource management for CROWN. Traditionally, the focus is on:
- time on the antenna
- the available energy
- or the required computational power.
CROWN adds another dimension: the system should be able to perform different tasks simultaneously on different parts of the antenna. This creates, with the antenna share, the resource for maximum efficiency and flexibility.
Artificial intelligence enables more efficient solutions
The resource allocation is based on a Quality-of-Service approach rooted in telecommunications and now successfully used in many areas. This creates an optimization problem that normally requires high computational effort to solve.
For a significantly more efficient solution, Fraunhofer FHR uses methods from artificial intelligence (AI), such as reinforcement learning. To solve the antenna-element allocation problem, a Monte Carlo Tree Search-based method was developed.
Fraunhofer FHR validates the resource management in CROWN with support from a simulation environment CoRaSi (Cognitive Radar Simulator). This is continuously developed at the institute. With CoRaSi, existing and future RF systems can be virtually modeled. In any scenario, new algorithms such as tracking, classification, and indeed resource management can be tested.
Follow-up project continues development
The functionality of the CROWN demonstrator was presented to the European Defence Agency (EDA) and the defense ministries of the seven participating nations in a laboratory demonstration. This also marked the project’s completion. In December 2025, the successor project SCEPTER started with 14 European partners under the European Defence Fund (EDF). A future deployment possibility for the system is, for example, unmanned flying platforms, as they have very high requirements for Size, Weight and Power (SWaP). Fraunhofer FHR again takes a central role in the development and integration of the resource management for real systems.