A Method of Virtual Array Aperture Extension for FMCW MIMO Phase-Coded Radar

In the multiple-input multiple-output (MIMO) phase-coded radars, the virtual array aperture (VAA) depends on the maximum physical distance between the transmitting and receiving antenna. Most of the existing VAA extensions focus on the phase compensation of echoes, which introduce no extra resources in terms of the transmitting waveforms. In this paper, we proposed a method to extend the VAA by taking advantage of the phase modulation of the inter-pulse phase coding radar. This method continuously applies phase modulation to the transmitting waveforms to introduce extra azimuth information. Under this premise, less prior information and phase compensation are needed to utilize the digital beam forming (DBF) due to the pre-modulation. Moreover, the proposed method is based on binary phase modulation (BPM), in which case the modulation complexity is effectively suppressed. The effectiveness of the proposed methods is demonstrated through simulation results and experiments.