Sub-Nyquist Affine Antenna Switching for Low-Complexity Angle–Doppler Estimation

Abstract

Antenna switching enables low-complexity sensing with a single radio-frequency chain, but target motion couples the switching sequence with Doppler-induced phase evolution. This coupling makes joint two-dimensional direction-of-arrival (DoA) and Doppler recovery rely on a computationally expensive three-dimensional (3D) search. This paper proposes an affine switching strategy for angle--Doppler estimation in integrated sensing and communication arrays. By sequentially switching across affine contours of a planar array, Doppler appears as a deterministic shift of the two-dimensional spatial spectrum in each switching sweep. Multiple sweeps with different slopes then recover the physical DoA and Doppler parameters by linear inversion after per-sweep spatial estimation. Simulations show that, compared with an implemented direct 3D grid-search baseline, the proposed method exhibits a lower signal-to-noise ratio threshold for successful initialization and substantially lowers runtime, while shifted-domain aliasing remains the main limitation in multi-target scenarios.