Acoustic detection, bearing estimation and source localization of specific audio events, such as drone detection and impulsive sound localization, could play a decisive role in security applications, and in search and rescue. The current state of digital MEMS microphones, including their sensitivity and acoustic overall point, enables their use for such applications. Moreover, their tiny size and weight make the creation of smaller and lighter systems possible. These systems can be mounted on stationary platforms, such as roofs and fences, or on dynamic platforms, such as robots and drones. At Fraunhofer-Institut FKIE, we are developing the LUCY system (Listening system Using a Crow’s nest arraY). The acoustic technology is composed of microphones arranged in a so-called pseudo “Crow’s Nest Array” (CNA) in combination of array processing techniques, such as beamforming, to estimate the positions of sounds for the previously mentioned applications. The spatial distribution and number of microphones in arrays has a crucial influence on the bearing estimation of audio events. In this paper, LUCY will be presented, and its performance evaluated in various open field experiments, will be exposed.