Dual-antenna passive synthetic aperture DOA estimation for airborne platforms

This work presents a dual-antenna passive synthetic aperture direction-of-arrival (DoA) estimation approach for compact airborne sensors. A physics-based model is employed, incorporating spherical wave propagation, Doppler effects, and a 200 km line-of-sight, and is implemented in an in-house radar simulator. The corresponding Cramér-Rao lower bound (CRLB) is derived to analyze the estimator's behavior and, in particular, to explore the trade-off between aperture length Q and number of snapshots K. Computer simulations conducted over a 0-50 dB SNR range demonstrate high azimuth and elevation accuracy, convergence of the root-mean-squared (RMS) error to the theoretical lower bound, and robustness. The proposed scheme offers a lightweight, low size, weight, and power (SWaP) solution for passive airborne sensing platforms.