This work describes a millimeter-wave six-port vector detector applied to time difference of arrival (TDOA) system operating around 60 GHz. The proposed system is mainly based on a MMIC six-port circuit built up with passive mixers, 90° phase-shifters, active and passive dividers and manufactured in MMIC technology. A dedicated calibration procedure is developed to yield sensitive detection enabling to determine TDOA accurately. Based on this six-port technology, an original localization technique is implemented to minimize the degradation of the location error.