Propagation effects of an intervisibility measurement system operating in the SHF band

A study was conducted to determine the limiting propagation effects on the performance of a microwave system that could be used to detect the optical visibility to one another of two vehicles, separated by up to 10 km, in irregular, obstructed terrain. The study had four objectives: (1) to demonstrate what effects signal variability has on the intervisibility decision process; (2) to identify the possible sources of the signal variability and to estimate the magnitude of each source's contribution to the total variability; (3) to obtain propagation loss data, over various types of terrain and obstructed paths, which could be used to predict received signal variability due to propagation over similar paths; and (4) to use the measured data to determine the performance of simulated intervisibility measurement system. A measurement system was prepared and sent to Ft. Hunter Liggett, CA, where propagation path loss was measured over several selected paths of varying lengths, varying path geometrics, and varying amounts of vegetation and rock outcroppings.