Atmospheric turbulence effects on radar systems

Atmospheric turbulence has been shown to have measurable effects on several aspects of radar performance. In this paper we discuss the perturbation of the angle-of-arrival (AOA) of radar beams caused by the atmosphere, the effects of lognormal- and Weibull-distributed clutter on detection performance, and the detection probability of ultrawideband pulses propagated through the atmosphere in the presence of turbulence and Gaussian noise. We find that AOA effects are on the order of a few microradians, which is a negligible level for most applications, but that clutter and noise, when combined with turbulent fluctuations, give some surprising results when the ratio of signal to clutter and noise is calculated. The detection of ultrawideband pulses is analogous to the “needle in a haystack” problem. In this paper, we present theories describing each of these phenomena, together with calculated results. For AOA, we have made measurements for one-way propagation that agree well with this theory, but the other phenomena have yet to be measured.