Beampattern optimisation for sub-arrayed MIMO radar for large arrays

The estimation of the direction of arrival (DOA) of signals in the far-field of an array has been an area of continued research. Recent advances in MIMO radar techniques have led to results whereby prior knowledge of the approximate target locations is used to generate arbitrary signals which are transmitted from an active array to improve DOA estimates. This would be a useful in a scenario such as target tracking. However, this neglects the complexities of the hardware required for larger arrays, and further, the amount of computation required on the transmit side alone. A sub-optimal method employing sub-arrays to reduce hardware requirements, and a low complexity algorithm to determine the optimal steering vectors for the arrays is presented and compared to the optimal full diversity transmit strategy.