On the Cramer-Rao Bound for Direction Finding of Correlated Signals

In this paper we present compact closed form formulas for the Cramer Rao Bound corresponding to the joint estimation of the directions-of-arrival, the signal covariance matrix, and the noise variance. Using these formulas we investigate the effect of signal correlation on the achievable accuracy of direction finding system in a correlated signal environment. As expected, estimation accuracy decreases with increasing correlation magnitude. We observe that under certain conditions (small aperture, high correlation magnitude), correlation phase has a strong effect on DOA estimation accuracy.