SEKE: A computer model for low altitude radar propagation over irregular terrain

SEKE, a new site-specific propagation model for general terrain, makes use of the original Lincoln Laboratory models geometrical optics (GOPT), low altitude propagation spherical earth (LAPSE), and low altitude propagation knife edges (LAPKE) to compute multipath, spherical earth diffraction, and multiple knife-edge diffraction losses. The proper algorithm is selected based on terrain geometry, antenna and target heights, and frequency. Comparison of model predictions with measurements over several paths ranging from level to rough at five frequencies (X-band through VHF) is presented. A brief discussion on the performance of SEKE over general terrain with respect to the expected performance of the two other general terrain-specific models (Longley-Rice and terrain integrated rough earth model (TIREM)) is given.