Photonics-based broadband radar target simulator for generating micro-Doppler signatures.

Micro-Doppler (MD) signatures provide radar systems with an additional dimension, significantly enhancing their capabilities in target detection and identification. However, there is currently a lack of broadband radar target simulators (RTSs) capable of generating MD signatures. To address this issue, this paper proposes a photonics-based RTS. The emitted signal from the radar under test (RUT) is modulated onto a broadband optical source. The optical spectra are then tailored to simulate micro-motions. Through frequency-to-time mapping, the optical spectra are converted into simulated echoes, allowing the generation of MD signatures. In the experiment, X-band radar signals with 4 GHz bandwidth are processed, and MD signatures corresponding to human walking and bird flight are successfully generated.