Effects of Naturally-Occurring Propagation Disturbances on Discrete Focused Arrays

摘要

The disruptive effects of ionospheric irregularities on space-based surveillance radars is considered. Propagation theory is used to first describe the parameters critical to such systems and to incorporate ionospheric parameters into that model. This is done using the equivalent phase screen approach with a statistical model of the in situ irregularity structure. The primary limitation that scintillation places on radar performance is the loss of spatial coherence, i.e., the resolving power of the radar. This, in turn, depends critically upon the turbulence strength, anisotropy, and motion of kilometer-scale irregularities. Although a complete spatial and temporal morphology of high-latitude structure is not yet known, data are available for near worst case performance estimates. Spaced receiver scintillation data directly provide all of the parameters critical to the performance analysis. Samples of such data from the auroral zone and central polar cap are presented; they show that radars with moderate-sized apertures may suffer degradation at some latitudes and local times. (Author)