Three-Element Non-Uniform Linear Array Design Strategy for Mobile Orthogonal Frequency Division Multiplexing Radar Using Supervised Displaced Phase Centre Antenna

Abstract

In this paper, we propose a three-element nonuniform linear array (NULA) design strategy for an OFDM-based radar system installed on a moving platform. The need to suppress Doppler-spread clutter induced by platform motion requires the use of space–time cancellation approaches, such as displaced phase centre antenna (DPCA) or space–time adaptive processing (STAP). In particular, the recently introduced thresholded-DPCA reciprocal filter (T-DPCA-RF) was demonstrated to be especially effective in detecting moving targets within a stationary scene using OFDM waveforms on transmit. This is mostly due to the T-DPCA-RF capability to process the received signals in batches of arbitrary length, independent of the OFDM framing structure. The three-element receiving NULA design strategy for multi-channel DPCA processing proposed in this work builds upon this feature of the T-DPCA-RF. Although previous research studies have demonstrated the advantages of NULA in multi-channel DPCA, the antenna positions were chosen based on a heuristic criterion. The NULA design strategy proposed in this paper provides guidance for antenna positioning by enforcing a constraint on the DPCA filter response that prevents blind velocity effects within a specified target velocity range of interest. The effectiveness of the multi-channel DPCA detector using the NULA designed with our strategy is validated through experimental data, extending the scope of previous studies in this area.