Automatic Extrinsic Calibration for a Drone Detection System Using Cooperative Drones

With unmanned aerial systems (UAS) becoming more commonplace, the threat they pose also increases. Therefore, Counter-UAS (C-UAS) systems become increasingly important to protect critical infrastructure and/or public events. Because UAS are difficult targets to detect, multi-sensor systems are a preferred means of detection. In order to achieve a successful fusion of the involved sensors' data, the system needs to be calibrated. For non-stationary applications the C-UAS system has to be set up each time it is deployed and needs to be extrinsically calibrated each time as well. The process of setting up and calibrating is typically conducted by the operator of the system, who often are not experts in the sensors themselves. Therefore, we propose an automated calibration process using a cooperative UAS to estimate each sensors' biases in azimuth and elevation. Additionally, different mathematical measures are used to automatically interpret the success of the calibration and provide additional information to the operator. The method is applied and evaluated on real-world data, and its accuracy and robustness are assessed.