(M.N. El Korso). polarized far-field sources and in [27], the authors studied the angular resolution limit for far-field sources in the presence of modeling errors. Moreover, in [28], the authors provide a novel methodology to derive an approximation of the resolution limit. Nevertheless, to the best of our knowledge, no works have been done to quantify the resolvability of two closely spaced near-field sources in the non-uniform linear array (NULA) context for the general case 1 (general case, means that the time varying source signals, the noise variance, the range and the bearing are all unknown parameters). Consequently, the goal of this paper is to fill this lack by addressing the following question: "What is, in a nearfield source scenario, the minimum source separation required, under which two near-field sources can still be correctly resolved?" To this end, one common tool is the distance resolution limit (DRL) of two closely spaced sources, defined as the minimum distance with respect to the sources for which allows a correct resolvability. The DRL can be derived based on one of the following three fundamental approaches: i) the analysis of the mean null spectrum [30], ii) the detection theory [19,23] (using a binary hypothesis test and a proper generalized likelihood ratio test [27]), or iii) the estimation accuracy (namely, based on the Cramér-Rao