Photonics-Assisted Wideband RF Source Localization Method Based on Synthetic Aperture Interferometric Detection

Angle of arrival (AOA) is one key parameter for passive signal source localization. However, with the increase in RF systems' instantaneous bandwidth and working frequency, it is a great challenge for traditional narrowband array signal processing methods to achieve effective AOA measurement of wideband RF sources. This paper proposes a photonics-assisted wideband RF source localization method based on synthetic aperture interferometer radiometer (SAIR) detection. The proposed method introduced cross-power spectrum (CPS), which can characterize the interference at different frequencies to define the wideband visibility function. Then the wideband SAIR detection is achieved from the wideband visibility function, which is Fourier transformed in the spatial domain and then performs integration in the frequency domain. Numerical simulation and proof-of-concept experiment results show that the proposed method can suppress the grating lobes caused by large element spacing. With a microwave photonic (MWP) channelizer and an antenna array, a wideband signal covering 16–20 GHz is detected. The AOA resolution of the system is 3.54°, and the power of the maximum grating lobe in the AOA measurement is suppressed by over 80%.