Transponder-based ADLS: With these systems, the position of flying objects is determined by the transponder signals they emit. Only flying objects equipped with a transponder are recognized. These systems are very accurate and require less infrastructure on the ground. Radar-based ADLS: These systems use radar signals to detect aircraft in the vicinity of wind turbines. They can detect all flying objects, regardless of whether they have a transponder or not. However, radar ADLS requires more technical infrastructure and can be more expensive to install and maintain.