UAV Geo-Localization for Navigation: A Survey

During the flight, Unmanned Aerial Vehicles (UAVs) usually exploit internal sensors to determine their position. The most useful and used one is the Global Positioning System (GPS), or, more in general, any Global Navigation Satellite System (GNSS). Modern GPSs provide the correct device’s location with a few meters of displacement, especially in a scenario with good weather and open sky. However, the lack of these optimal conditions highly impacts the accuracy. Moreover, in restricted areas or fields of war, several anti-drone techniques are applied to limit UAVs capabilities. Without proper counter solutions, UAVs cannot continue their task and sometimes are not even able to come back since they are not aware of their position. During the last years, plenty of techniques have been developed to provide UAVs with a knowledge of their location that is not strictly connected to the availability of the GPS sensor. This research field is commonly called Geo-Localization and can be considered one of the hot topics of UAV research. Moreover, research is going further, trying to provide UAVs with fully autonomous navigation systems that do not use hijackable sensors. This survey aims to provide a quick guide to the newest and more promising methodologies for UAV Geo-Localization for Navigation tasks, showing the differences and the related application fields.