Blind source separation with the generalised estimation of multipath signals algorithm

Blind source separation (BSS) techniques have traditionally been applied in wireless communication systems to separate signals of interest from multiple sources or users in the absence of training data. Such techniques have received comparatively little attention to date in the context of radar systems, and this is mainly because the signal needed for matched filtering (coherent processing) is known a priori. In practice, active and passive radar systems are required to operate in a congested spectrum where an effective interference mitigation capability is critical to successful operation. This study considers the application of the generalised estimation of multipath signals (GEMS) algorithm for BSS to estimate interference waveforms present in the same frequency channel as the signal of interest (SOI). Interference components at the receiving node(s) of the system are reconstructed using these estimates, with site-dependent complex-scales, time-delays and Doppler-shifts to account for multipath effects, and then subtracted from the data in the time domain. A practical demonstration of the proposed method is illustrated using real data from an experimental high frequency radar system that receives a mixture of frequency-modulated and amplitude-modulated continuous waveforms.