Multichannel Forward Scatter Radar Using Arbitrary Waveforms

This paper presents a comprehensive exploration of multichannel forward scatter radar (MC-FSR), focusing on advanced space-domain and space-time processing techniques for target detection and localization. While previous studies have introduced multichannel configurations in FSR, a generalized modeling framework that accommodates both active and passive scenarios — and supports arbitrary transmitted waveforms — remains lacking. Leveraging the core principles of FSR, we develop an advanced signal model that captures amplitude modulation induced by targets across array elements, in addition to the modulation observed over time. This spatial modulation enables target detection and direction of arrival (DOA) estimation solely from non-coherent amplitude data. We propose a spatial-domain processing scheme that exploits these amplitude variations for detection and DOA estimation, complemented by a the space-time processing approach that integrates temporal and spatial samples to generate a detailed Doppler-angle representation of the observed scene. The advantages and limitations of the MC-FSR system are thoroughly examined through technical discussion, simulations, and real-world experiments based on commercial software-defined radios. The results affirm the feasibility and effectiveness of the multichannel FSR system and the proposed processing schemes, even when exploiting amplitude modulated waveforms such as OFDM signals, demonstrating significant potential for practical applications.