Simulation of a spread spectrum coherent beacon system for phase measurement

Satellite based coherent beacon systems have been used for ionospheric studies by measurement of the differential phase between the carriers. A simulation study of such a system is presented in this paper, along with the differences in performance occurring by using a spread spectrum beacon over this conventional one.Usage of spread spectrum has the desirable properties of exhibiting a narrowband interference suppression effect, along with robustness to fading. Such a system can resolve the initial phase ambiguity as the ground receiver tracks and acquires the pseudo-random codes separately, then extracts the carrier and combines them to provide differential phase measurement. We use band-limited spreading waveforms for the carrier and code to prevent self-interference, and we evaluate system performance over a frequency selective Rayleigh channel in the presence of various noise sources.