Ranging Estimation and Implementation with Cellular signals for UAV Navigation

With the shortcomings of accuracy and security in global navigation satellite systems (GNSS), the exploration of cellular signal ranging and localization methods for complementary or alternative unmanned aerial vehicle (UAV) navigation is promising. However, when the GNSS signal suddenly disappears or is spoofed, it is still highly challenging to achieve sustainable ranging and localization of UAVs on the existing mobile communication network and infrastructure. In particular, the reliability and latency of switching and combining between the two navigation systems. In this paper, we tackle this tricky problem by a ranging method based on the time of arrival (TOA) of cellular signals, where cell search process has been adopted to calculate the frame start position. The method makes ingenious use of the synchronization information of the physical broadcast channel (PBCH), avoiding the addition of extra equipment and effectively reducing costs. Moreover, the final ranging results are still unstable due to randomness of base station clock deviations. To overcome this difficulty, we first obtain the statistics of frequency division duplex (FDD) and time division duplex (TDD) base station clock deviations. And then, we predict and compensate the difference between the clock deviations with a timing prediction model. Experimental results demonstrate that the radial basis function network is more sensitive to the variation of base station clock deviations. The feasibility and superiority of the method are verified by field measurement experiments, while the accuracy of UAV navigation information can be significantly improved.