Based on concentration measurements from spatially distributed electronic noses, the location of a point source is to be determined. It is assumed that the emitted substance is transported by advection caused by a known homogeneous wind field and by diffusion. A new two-step approach for solving the source localization problem is presented. The new approach overcomes the problem of poor convergence of iterative algorithms, which try to minimize the least squares output error. An optimal weighting strategy is introduced, which yields to approximate maximum-likelihood estimates for the source position.