NLR BVLOS technology demonstrator drone

R&D case: Detect And Avoid system (ADACORSA)

To enable safe airspace integration of unmanned aircraft, a Detect And Avoid (DAA) system is required to evade other (manned) aircraft. One solution is to use a Cooperative Traffic Sensor based on transponder signals. Such a sensor is not yet available with a small form factor suitable for unmanned aircraft. Within the Airborne Data Collection on Resilient System Architectures (ADACORSA) project, such a sensor will be developed and tested in cooperation with the partners.

The challenge

The main challenges of the project are:

  • The form factor and power requirements of current DAA systems are not suitable for small and mid-sized unmanned aircraft.
  • Due to frequency saturation of the manned aircraft transponder frequencies, drones cannot be equipped with ADS-B transponders.
  • Manned aircraft with both Mode-S and ADS-B transponders need to be detected.

The solution

  • Miniaturisation of the DAA system suitable to be integrated onboard of small and mid-sized unmanned aircraft
  • Sensor suite advancement to include a direction finder to measure the azimuth such that the relative position to the intruders is known
  • Information from ADS-B (manned intruder aircraft) will be used to further increase detection of current airspace users

What did we do?

NLR develops a Direction Finder for the Cooperative Traffic Sensor (CTS) and integrates this with a Mode-S interrogator, developed by project partner Celestia Technology Group. The DAA system uses algorithms developed by NLR for semi-automatic avoidance of other aircraft. These algorithms feature both Remain Well Clear (RWC) and Collision Avoidance (CA) functionalities.

The RWC functionality takes into account the rules-of-the-air to calculate a new route for the unmanned aircraft. The calculation is performed onboard to be independent of a data link and allows a fully autonomous system in the future. The DAA system will be integrated and flight tested in the DAA Flying Testbed at the NLR Drone Flight Test Centre. Finally, the developed system will be demonstrated in a logistic support use case

NLR BVLOS technology demonstrator drone

This project is co-financed from the Allowance for Top Consortia for Knowledge and Innovation (TKl’s) by the Ministry of Economic Affairs and Climate Policy.

NLR Marknesse

Information

Latest cases

Ariane 62 and 64 European launch systems.
Platform System Design

25 February 2026

R&D case: Wind tunnel modelling for Europe's Ariane 6 launch system

The development of the Ariane 6 launcher was geared towards creating a reliable, flexible, and competitive European launch system. NLR played an important role in this endeavour by providing wind tunnel models at various development stages.

Sustainability and Environment

16 February 2026

R&D case: Liquid hydrogen composite tanks for civil aviation

Hydrogen has been identified as a key priority to achieve the European Green Deal for a sustainable economy. By converting the construction of the hydrogen tank from existing metallic solutions to composites, the liquid hydrogen (LH2) composite tank will achieve weight savings that enable the advancement of liquid hydrogen as a sustainable fuel source for civil aviation. This will lower the carbon footprint of air travel and extend the flight range of aircraft by reducing construction weight and cost.