Robust mixed-order root-music

Several typical situations unfavorable for second-order direction-finding methods are known to be easily overcome by means of higher-order techniques. In turn, in typical situations unfavorable for higher-order methods, second-order algorithms often perform quite well. Therefore, appropriately combining covariance- and cumulant-based techniques into one scheme, it is possible to obtain an algorithm with an improved robustness. In this paper, we propose two modifications of such combined methods, referred to asmixed-order root-MUSIC.