reduction of cramer-rao bound in arbitrary pre-designed arrays using altering an element position

simultaneous estimation of the range and the angle of close emitters usually requires a multidimensional search. this paper proposes analgorithm to improve the position of an element for arrays designed on the basis of some certain or random rules. in the proposed method,one element moves along the same previous direction, maintaining its vertical distance from each source, to reach a constellation with lesscramer-rao bound (crb). the efficiency of this method has been demonstrated through simulation and a comparative study has beenconducted, contrasting both the crb and the determinant of the received signal’s covariance matrix before and after applying our proposedscheme.