A Modified Root Polynomial Algorithm

Polynomial rooting direction finding (DF) algorithms are a computationally efficient alternative to search based DF algorithms for uniform linear arrays (ULA) with equal element radiation patterns. However, in the second order (SO) statistics based root MUSIC (RM) algorithm the number of roots that has to be calculated equals 2N-2 where N represents number of array elements. The directions of arrivals (DOA) are estimated from the L pairs of roots closest to the unit circle where L represents number of sources. When number of array elements is large this leads to large computational load and can introduce significant numerical errors in the estimated DOA. In this paper we derive the SO statistics based modified root polynomial (MRP) algorithm requiring the determination of only L roots