The Cramér-Rao Bound (CRB) for direction of arrival (DOA) estimation has been extensively studied over the past four decades. with a plethora of CRB expressions reported for various parametric models. In the literature. there are different methods to derive a closed-form CRB expression. https://www.ngetikin.com/limited-save-Apple-iPhone-14-Pro-Clear-Case-with-MagSafe-save-big/