Experimental Observation and Statistics of Multipath from Terrain with Application to Overland Height Finding

Data is presented from an airborne experiment designed to evaluate electromagnetic pulse scattering from a variety of terrain types for the application of overland height finding. The one-way propagation data was collected at ultrahigh frequency (UHF) and very high frequency (VHF) frequencies using a 3-MHz pulsed CW signal with the radars mounted on two aircraft. A statistical analysis of the data shows that the probability of a detectable ground reflection and the strength of that reflection vary as a function of the terrain roughness. We introduce a broad-band synthesis technique in which Fourier theory is used to generate a time-domain response from a CW propagation model. Results from this technique agree well with the experimental observations, but the lack of detailed terrain information does not allow exact reproduction of the fine details.