Systems and method are provided for using millimeter-wave radar for terrain-aided navigation in support of autonomous guidance, landing, and mapping functions in all weather for unmanned air vehicles (UAVs). In an embodiment, a UAV can generate a map, based on millimeter-wave (MMW) radar returns, that rejects a large number of radar measurements as clutter and generates a flight path using waypoints based on the map. Embodiments of the present disclosure provide a means of correlating MMW radar returns with high resolution terrain maps to enable navigation in GPS-denied environments. This process significantly reduces cost, development time, and complexity when compared to conventional approaches.