On the Cramer-Rao Bound for Sparse Linear Arrays

Using the stochastic Cramer-Rao bound for direction estimation we study the performance of nonuniformly spaced linear antenna arrays. We show that the estimation accuracy of such arrays depends primarily on the integrated SNR and the array aperture. It depends rather weakly on the exact layout of the antennas within the aperture. We also note that almost any nonuniform linear array is capable of estimating more signals than the number of antennas, but accuracy degrades quickly once the number of signals exceeds the number of antennas.