Abstract: This article investigates the issue of direction of arrival (DOA) estimation for multi-input multi-output (MIMO) radar in symmetric αstable (SαS) clutter. Two algorithms are proposed, i.e., a fractional lower order minimum variance distortionless response (FrMVDR) DOA estimation algorithm and an infinity-norm normalization MVDR (Inf-MVDR) DOA estimation algorithm. For the FrMVDR algorithm, the characteristic exponent value of the SαS clutter is first estimated, and then the fractional lower order output power of MIMO radar is minimized to realize DOA estimation. To avoid characteristic exponent estimation, another Inf-MVDR algorithm is developed, which first transformes the SαS clutter into a clutter with bounded output power through infinity-norm normalization, then uses the conventional MVDR algorithm to estimate DOA. Computer simulations verify the effectiveness of the two proposed algorithms. The results also show that spatial diversity of MIMO radar can significantly improve the precision of DOA estimation in impulsive clutter.

Key words: impulsive clutter, MIMO radar, direction of arrival estimation, fractional lower order statistics, infinity-norm normalization