Cramér–Rao Lower Bounds Comparison for 2D Hybrid–MIMO and MIMO Radar

The Hybrid MIMO Phased Array Radar (HMPAR) is a multisensor radar architecture that merges the concepts of a traditional phased array radar with the colocated multiple-input multiple-output (MIMO) radar. This radar system is composed of a large number of T/R elements, MP, organized into M subarrays of P elements each. The subarrays can be electronically steered in different directions and driven by separate transmit waveforms. Previous publications focused attention on the transmit signaling strategies and transmit beampatterns. Here, we provide the analytical Cramér-Rao lower bounds (CRLB) on the target location for a planar HMPAR. Fixing the total number of T/R elements, we create two scenarios, in order to compare the CRLB values of different HMPAR configurations to the MIMO CRLB. Moreover, we assume that the radar systems employ transmit signals that follow the intrapulse beamscan concept, namely signals that rapidly scan the field of view. Depending on the scenario, results show that the HMPAR is able to achieve lower CRLB values than the MIMO.