Fast Multi-target Sensing and Tracking for Directional Array-Deployed UAV Systems

Accurate sensing and fast tracking are challenging for large-antenna unmanned aerial vehicles (UAVs), due to computational capacity limits. This paper presents a novel simultaneously multi-target sensing and tracking scheme for millimeter-wave (mmWave) large-antenna UAV systems. By exploiting the low-rank and high-directivity nature of mmWave multi-antenna channels, a new directional beamformer is designed for the UAV. As a result, the horizontal angles of arrival (AOAs) can be roughly estimated and the number of targets can be quickly identified. We also propose a low-complexity multi-target azimuth and elevation AOA estimation algorithm. The asymmetric discrete Fourier transform (A-DFT) is employed to reduce the dimension of the received signals. By using the elevation estimates for azimuth AOA estimation, the mismatching of the estimated parameters for different targets is avoided. Simulations show that the proposed scheme can accomplish the task of high-accuracy multi-target sensing and tracking in a short period of time.