Abstract: A radio frequency distance measuring system and method where two continuous wave carrier signals, derived from a stable frequency source, are radiated from a known reference point. The frequency of the first continuous wave carrier signal is displaced from the frequency of the second continuous wave carrier signal by a selected difference frequency. When received at the unknown point, the two continuous wave carrier signals are mixed to provide a difference or beat frequency marker signal, delayed in arrival at the unknown point from the known point by the speed of light. A locally generated marker signal is derived from a stable frequency source at the unknown point, and has the same frequency as the difference frequency signal.