Phase compensation and processing in multiple-input-multiple-output radars

In this study, the issue of phase discontinuity in multiple-input-multiple-output (MIMO) radar systems is analysed and described in detail, together with an efficient way for processing MIMO radar data by means of discrete-time Fourier transform (DFT) fast Fourier transform (FFT). In particular, here it is shown that the phase history of a point target illuminated by an MIMO radar shows a number of discontinuities because of the geometry of the antennas. It is also shown that these become negligible in the far range, whereas they represent an issue in the short range if not compensated properly because, in turn, they prevent DFT-based algorithms correctly focusing the received signals. It is shown that data from MIMO radars have to be pre-processed in order to allow an efficient DFT-based focalisation. For this purpose, together with a theoretical description of the problem, a sub-optimal algorithm is presented, discussed and tested against real data gathered by the Joint Research Centre (JRC) MIMO radar system.