UAVs You Can´t See or Hear - A Survey of Key Technologies

The paper addresses unmanned aerial vehicles (UAVs - aka drones) designed to be undetected by humans, i.e. stealth drones, or more generally, to have a minimal impact on living beings and environment, i.e. ´blue´ drones, in the sense of preserving unaltered the blue color of the sky. Being ´blue´ might be highly desirable in the future when drones will proliferate in large numbers, stealth is a special case, desirable to covert military and security operations. The paper explores general characteristics of blue drones and alternatives of making them, offering both system and component level solutions.