Rotational Doppler Resolution of Spinning Target Detection Based on OAM Beams

The rotational Doppler resolution of spinning target detection based on orbital angular momentum (OAM) beams is studied. First, the principle of rotational Doppler effect and the formulation of Doppler frequency shift are analyzed. Subsequently, the echo signal model of spinning target detection using OAM beams and its ambiguity function are derived. The resolution of angular velocity with single radar pulse is obtained. Moreover, the detection method of Doppler frequency shift and angular velocity is proposed based on multiple radar pulses. Theoretical and simulation results demonstrate that the resolution of angular velocity is decided by the OAM index and the pulse duration, and this resolution can be improved when high-order OAM beams are used to detect the spinning target. This work can benefit the development of OAM-based target detection methods and the design of radar systems.