Radar Sensing in General Aviation: For Purposes of Detect and Avoid

J.B. Maas

Research output: ThesisDissertation (TU Delft)

70 Downloads (Pure)


Safety is crucial in aviation. This includes the category of General Aviation, which consists of flights that are not performed by commercial airliners. Many of these vehicles are small in comparison to the aircraft used for commercial transport, providing seats for two or four persons. Despite their limited size, accidents involving General Aviation aircraft can be costly or even lethal. Therefore, a high priority is placed on the prevention of accidents in General Aviation. The importance of Situation Awareness In order to prevent collisions, a pilot needs to have an accurate and complete situation awareness, so that he or she can take appropriate action to avoid hazardous situations. This awareness includes knowledge about the own aircraft, as provided by the flight instruments in the cockpit. Besides this information, the pilot needs to have information about the immediate environment. This immediate environment can contain many different objects of which the position relative to the aircraft needs to be known. Stationary obstacles such as towers, windmills and other buildings are relevant when flying at low altitudes. Also the curvature and elevation of the landscape are relevant for a pilot flying near the ground, such as when taking off or landing at an airfield. Dynamic obstacles can also pose threats to a pilot. These obstacles can be other aircraft, and birds are also known to cause dangerous situations for aircraft. And the development of unmanned air vehicles also leads to more conflicts between drones and aircraft. Situation Awareness Limitations in Visual Flights For flights taking place in Instrument Flight Rules, a situation awareness solution is guaranteed and enforced; all aircraft must be equipped with the correct transponders and aircraft that do not comply are tracked down by military radar. But for flights under Visual Flight Rules, there are no such regulations, for various reasons. In these flights, which make up the majority of General Aviation flights, the pilot relies on eyesight in order to guarantee separation with other aircraft and the ground. At times, human eyesight is insufficient to guarantee safety. This can be a consequence of a high workload for the pilot, changing weather conditions, the direction of where an object is coming from, and other reasons. This can lead to unsafe situations for the pilot and for others, both in the air and on the ground. Technical solutions have been developed that can assist the pilot in his or her situation awareness tasks. Unfortunately, these solutions all involve the use of transponders of some kinds, which makes them dependent solutions. These soluxitions can only provide an indication of safety, but no guarantee, because aircraft without transponders cannot be detected. An independent sensing solution in General Aviation for purposes of detect and avoid can contribute significantly to safety in the air. The aim of the research in this dissertation is to contribute to the actualization of such a solution…
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Delft University of Technology
  • Hoekstra, J.M., Supervisor
Award date30 Jun 2022
Print ISBNs9789463843423
Publication statusPublished - 2022


  • Airborne Radar
  • General Aviation
  • Detect and Avoid
  • Surveillance
  • Conflict Detection


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