Two well developed techniques in emitter location estimation using time difference of arrival (TDOA) are analyzed and compared for different situations and noise values. These techniques are a passive localization algorithm and a closed-form solution based on association by clustering. The advantages and disadvantages of these techniques are determined and supported by the simulation examples. Also, a hybrid model, using these two methods and including an iterative process based on maximum likelihood (ML) is presented and analyzed in performance. ©2008 IEEE.