The Doppler-Delay Characteristic of the Aeronautical Scatter Channel

The objective of this paper is to characterize the scattered components in an aeronautical channel in terms of delay and Doppler frequency. Geometric considerations make it possible to locate the scatterers on the ground and derive analytical expressions of their shape in the Doppler-delay domain. The delay and Doppler frequencies are at first described as a function of the horizontal distance to the specular reflection point. Subsequently, the spatial relationship is used to directly link delay and Doppler frequencies in one formula. The results show a very good match of the theoretical expressions and the measured data. The presented results are currently used to develop a three-dimensional model of the scatterers that enables us to define Doppler power profiles for arbitrary delays.