In recent years, unmanned autonomous vehicles have been used in diverse applications because of their multifaceted capabilities. In most cases, the navigation systems for these vehicles are dependent on Global Positioning System (GPS) technology. Many applications of interest, however, entail operations in environments in which GPS is intermittent or completely denied. These applications include operations in complex urban or indoor environments as well as missions in adversarial environments where GPS might be denied using jamming technology. If you ever wondered why camera technology is so effective on drones, what drives these powerful machines and how much of an impact vision-aided navigation has on various applications, your answers are encoded in this book. This will dive deep into the science behind some of these breath-taking drone technologies currently on the rise. Truthfully speaking, for the thrill-seeking engineering folks, welcome to the science behind the "Eye in the sky".