Vehicular-Motion-Based DOA Estimation With a Limited Amount of Snapshots for Automotive MIMO Radar

The problem of high-resolution direction-of-arrival (DOA) estimation based on a limited amount of snapshots in automotive multiple-input multiple-output (MIMO) radar has been studied. The number of snapshots is restricted to minimize target spread/migration in range and/or Doppler domains. A computationally efficient approach for side-looking arrays is developed, which combines the generation of motion-enhanced snapshots and MIMO technology, thus exploiting the movement of the vehicle and the spatial diversity of the transmit and receive antennas. Due to motion, a larger virtual aperture is obtained and the angular resolution is boosted, achieving the separation of targets that the traditional MIMO approach cannot discriminate, as well as better results than with other single snapshot DOA estimation techniques. Algorithm performance has been studied in simulations, and possible limitations have been discussed. In addition, the method has been verified experimentally with pointlike and extended targets, and good agreement between simulations and experimental results has been observed.