▁solutions ▁ ▁Spect ral ▁based ▁algorithm ic ▁solutions ▁can ▁be ▁further ▁class ified ▁into ▁beam form ing ▁techniques ▁and ▁sub space - based ▁techniques . ▁ ▁Be am form ing ▁technique ▁ ▁The ▁first ▁method ▁used ▁to ▁specify ▁and ▁automatically ▁local ize ▁the ▁signal ▁sources ▁using ▁anten na ▁arrays ▁was ▁the ▁beam form ing ▁technique . ▁The ▁idea ▁behind ▁beam form ing ▁is ▁very ▁simple : ▁ste er ▁the ▁array ▁in ▁one ▁direction ▁at ▁a ▁time ▁and ▁measure ▁the ▁output ▁power . ▁The ▁ste ering ▁locations ▁where ▁we ▁have ▁the ▁maximum ▁power ▁yield ▁the ▁DO A ▁estimates . ▁The ▁array ▁response ▁is ▁ste ered ▁by ▁forming ▁a ▁linear ▁combination ▁of ▁the ▁sensor ▁outputs . ▁ ▁Appro ach ▁over view ▁▁ ▁Where ▁R x ▁is ▁the ▁sample ▁cov ar iance ▁matrix . ▁D ifferent ▁beam form ing ▁approaches ▁correspond ▁to ▁different ▁choices ▁of ▁the ▁weight ing ▁vector ▁F . ▁The ▁advantages ▁of ▁using ▁beam form ing ▁technique ▁are ▁the ▁simplicity , ▁easy ▁to ▁use ▁and ▁understand . ▁While ▁the ▁dis adv antage ▁of ▁using ▁this ▁technique ▁is ▁the ▁low ▁resolution . ▁ ▁Sub space - based ▁technique ▁ ▁Many ▁spectral ▁methods ▁in ▁the ▁past ▁have ▁called ▁upon ▁the ▁spectral ▁decomposition ▁of ▁a ▁cov ar iance ▁matrix ▁to ▁carry ▁out ▁the ▁analysis . ▁ ▁A ▁very ▁important ▁break through ▁came ▁about ▁when ▁the ▁eigen - structure ▁of ▁the ▁cov ar iance ▁matrix ▁was ▁explicitly ▁invoked , ▁and ▁its ▁intr insic ▁properties ▁were ▁directly ▁used ▁to ▁provide ▁a ▁solution ▁to ▁an ▁underlying ▁estimation ▁problem ▁for ▁a