Radio Map Assisted Multi-UAV Target Searching

When acting as dynamic receivers, unmanned aerial vehicles (UAVs) have several advantages over the conventional static base stations for received signal strength (RSS) based target searching. It is highly likely that the RSS is becoming stronger as the UAV is moving towards the estimated coordinate, and this leads to a higher estimation precision for each localization update. On the other hand, despite its low cost, low energy consumption and simple hardware requirement, RSS can be severely influenced by land layouts, therefore the assumption of a simple free space propagation model may lead to poor estimation precision and even failure, especially for an area where the topography is highly complex. In this paper, we propose multi-UAV target searching with the assistance of radio maps, which contain abundant information of the topography influence on RSS. We generate radio maps from real topographic data, and derive the minimum mean square error estimator for multi-UAV target searching with the radio map knowledge for memoryless observations. Simulations for areas with complex topography, show that the localization precision and searching efficiency can be considerably improved with the assistance of radio maps.