Using in-phase and quadrature components of a received signal, spatial and temporal information is utilized to generate a maximum likelihood coefficient from the measured data to geolocate an emitter of unknown frequency. In one embodiment an iso-Doppler contour is generated having regions of high correlation to estimate location in which the maximum likelihood calculation uses two factors, one derived from a single aperture and one derived from bearing estimates, with the region of highest correlation corresponding to emitter location. Hypothesized in-phase and quadrature signals corresponding to an emitter location describe what the signals received at the aperture should be if the emitter is of a predetermined frequency and at a predetermined location, with these estimates used in the maximum likelihood algorithm.