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The multiple-input multiple-output (MIMO) radar combines ultra-wide angular illumination on transmit and narrow transmission angular resolution after processing on receive. Orthogonal waveforms are needed in theory for all independent transmitters, but this property is usually not achievable in practice, therefore leading to a degraded ambiguity function. In this study, the authors focus on phase codes waveform, which gives quasi-optimal angle and range resolution. On the other hand, they induce a harmful "floor" of high-level sidelobes in the range-angle domain. The authors propose to apply the orthogonal matching pursuit (OMP) to the MIMO radar signals. Therefore, it becomes theoretically possible to detect targets initially hidden by high-level sidelobes. Nevertheless, the authors identify phenomenon (grid granularity, neighbour influence) that lead to possible localisation error resulting in ghost targets. Considering this, the authors propose an extension of the OMP rejection step that includes, in addition to the expected target position, the neighbour positions within the uncertainty area. The authors show that this extension allows them to suppress the sensibility of the OMP to localisation error, even in case of very close targets. Finally, the authors demonstrate the performance of the proposed method on simulations as well as on experimental MIMO radar signals.

Coherent collocated MIMO radar is an emerging technology from which is expected several benefits since digital and adaptive beamforming are available at both transmit and receive sides. A large number of papers are dealing with theoretical analysis of those benefits. Nevertheless, few experimental performance assessments of those benefits have been reported. During the last few years, ONERA has built a powerful and versatile surface radar testbed named HYCAM. Its design included a MIMO mode in order to test the different classes of waveforms in real conditions (hardware defaults, clutter characteristics) which can hardly be modeled with accuracy. After a recall of the MIMO processing principles, this paper sums up the benefits and drawbacks that are expected from this technology and the need of experimentation to verify those expectations. Then we will present ONERA's HYCAM MIMO testbed and first results of MIMO trials using this system as well. Those experimental results will be linked to a more general discussion on impacts of hardware defaults on MIMO radar waveforms performances.

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