Effective HF Radar Installation in Challenging Terrain Environments for Homeland Security Applications

Emerging homeland security applications require low-cost and rapid installation of HF radar systems in challenging terrain environments. One example concerns hills with natural slope and surface irregularity and roughness. In this letter, through the investigation of radio-wave propagation in such an environment, we examine the effect of the slope and surface roughness of the terrain on the performance of HF radars. It is shown that the slope and surface irregularity affect the effective electrical spacing between array elements and cause beamforming and scanning errors, which lead to misdetection of targets. It is also shown by an investigation of an actual HF radar site in the area of Koko Head in Hawaii that scattering from surface roughness of the terrain adds extra error to the phase difference between antenna array elements (~30^°), hence degrades the radar performance further.