Techniques for locating a remote HF transmitter from single-site measurements

Techniques are developed for the location of a remote HF transmitter from single-site DF measurements on the incoming wavefront, coupled with ionospheric data. A simple method is detailed, which utilizes the Breit-Tuve and Martyn equivalent path theorems in a flat ionosphere approximation. It is shown to break down in this application only for high elevation angles and frequencies. Curved ionosphere generalizations of these theorems are developed to remove this breakdown. These generalizations are found to be remarkably accurate within the context of the neglect of magnetic field and non-spherical ionosphere effects, and are shown to applicable to the present problem.