Multipath propagation effects on low-angle radar tracking: an experimental evaluation

Meteorological and surface roughness effects on the accuracy of low-angle radar tracking are examined based on an analysis of experimental data. The data were recorded using a large synthetic antenna with an 18.4-m vertical aperture. The antenna was equipped with meteorological sensors so that both radar and meteorological measurements could be made at the same time. In addition to making measurements of the angles of arrival of the direct and indirect signals from a beacon, the antenna and the associated equipment were used to make measurements of the refractivity gradient. It is shown that the change in refractivity gradient may seriously degrade the accuracy of a low-angle tracking radar by introducing sizable deviations in the estimated target heights and causing the radar to lose track of the target.<>