Analysis of the Signals of Opportunity and Cooperative Based Positioning for UAS Navigation in Deep Urban Area

Autonomous navigation of most unmanned aircraft systems (UAS) is entirely dependent on GNSS. However, in deep urban area, the weak signal of Global Navigation Satellite Systems (GNSS) can be easily lost, thus UAS has no other reliable means of navigation. For this reason, autonomous navigation or surveillance like Unmanned Aircraft System Traffic Management (UTM) in deep urban area remains as a challenging problem. To tackle this problem, there have been great interests in positioning using signals of opportunity (SOP) including such as Long Term Evolution (LTE). More recently, a software defined radio for LTE positioning demonstrated a successful UAS flight test with a few LTE base stations. Although there are usually plentiful LTE base stations in urban area, they are primarily deployed to provide coverage to mobile communication users such that the base station network layout is subject to be suboptimal for positioning. And, it is not certain that SOP based on LTE could provide an appropriate positioning performance to safely navigate in deep urban area. This paper investigates the positioning performance of the current network of LTE base stations and the required augmentation of the SOP network to meet desired positioning accuracy in deep urban area of Seoul, South Korea. The paper also considers DSRC as another possible SOP ranging source and looks into the benefit of cooperative positioning with nearby UAS.