A simplified correlation technique for position location using earth satellites.

To derive range to a moving vehicle for surveillance and navigation purposes, the phase delays in sets of sinusoidal tones may be measured using synchronous satellites for signal relay. When the number of users is large, problems of rapid acquisition and measurement occur in multiple-access systems. This paper describes the selection and processing of an orthogonal tone set which has several useful features. The paper also presents a simulation of a simplified digital technique for the noise-free case, as well as for a composite signal buried in wideband noise. The digital simulation is also modified to include the proposed 'hard limiting' or clipping technique.